The corticobulbar tract conducts impulses from the brain to the cranial nerves.
These nerves control the muscles of the face and neck and are involved
in facial expression, mastication, swallowing, and other motor
functions.
The corticospinal tract conducts impulses from the brain to the spinal cord. It is made up of a lateral and anterior tract. The corticospinal tract is involved in voluntary movement. The majority of fibres of the corticospinal tract cross over in the medulla oblongata, resulting in muscles being controlled by the opposite side of the brain. The corticospinal tract contains the axons of the pyramidal cells, the largest of which are the Betz cells, located in the cerebral cortex.
The pyramidal tracts are named because they pass through the pyramids of the medulla oblongata. The corticospinal fibers converge to a point when descending from the internal capsule
to the brain stem from multiple directions, giving the impression of an
inverted pyramid. Involvement of the pyramidal tract at any level leads
to pyramidal signs.
The myelination of the pyramidal fibres is incomplete at birth and gradually progresses in cranio-caudal direction and thereby progressively gaining functionality.
Most of the myelination is complete by two years of age and thereafter
it progresses very slowly in cranio-caudal direction up to twelve years
of age.
There is some variation in terminology. The pyramidal tracts definitively encompass the corticospinal tracts, and many authors also include the corticobulbar tracts.
The nerve axons traveling down the tract are the efferent nerve fibers of the upper motor neurons. These axons travel down the tracts in the white matter of the spinal cord until they reach the vertebral level of the muscle that they will innervate. At this point, the axons synapse with lower motor neurons. The majority of axons do not directly synapse with lower motor neurons, but instead synapse with an interneuron that then synapses with a lower motor neuron. This generally occurs in the anterior grey column.
Nerve axons of the lateral corticospinal tract that did not cross over
in the medulla oblongata do so at the level of the spinal cord they
terminate in.
These tracts contain more than 1 million axons and the majority
of the axons are myelinated. The corticospinal tracts myelinate largely
during the first and second years after birth. The majority of nerve
axons are small (<4μm) in diameter. About 3% of nerve axons have a
much larger diameter (16μm) and arise from Betz cells,
mostly in the leg area of the primary motor cortex. These cells are
notable because of their rapid conduction rate, over 70m/sec, the
fastest conduction of any signals from the brain to the spinal cord.
Horizontal
section through the lower part of the pons, showing the fibers of the
corticospinal tract (#19) passing through the pontine nuclei
The nerves within the corticospinal tract are involved in movement of muscles
of the body. Because of the crossing-over of fibres, muscles are
supplied by the side of the brain opposite to that of the muscle. The nerves within the corticobulbar tract are involved in movement in muscles of the head. They are involved in swallowing, phonation, and movements of the tongue. By virtue of involvement with the facial nerve, the corticobulbar tract is also responsible for transmitting facial expression.
With the exception of lower muscles of facial expression, all functions
of the corticobulbar tract involve inputs from both sides of the brain.
The extrapyramidal system refers to tracts within the spinal cord involved in involuntary movement but not part of the pyramidal tracts. Their functions include the control of posture and muscle tone.
Damage to the fibres of the corticospinal tracts, anywhere along
their course from the cerebral cortex to the lower end of the spinal
cord, can cause an upper motor neuron syndrome.
A few days after the injury to the upper motor neurons, a pattern of motor signs and symptoms appears, including spasticity, hyperactive reflexes, a loss of the ability to perform fine movements, and an extensorplantar response known as the Babinski sign.
Symptoms generally occur alongside other sensory problems.
If the corticobulbar tract
is damaged on only one side, then only the lower face will be affected,
however if there is involvement of both the left and right tracts, then
the result is pseudobulbar palsy. This causes problems with swallowing, speaking, and emotional lability.
Severe disabling involuntary movements such as hemiballismus or severe chorea might exhaust the patient and become a life-threatening situation.
In the past, this condition was treated by partial section of the pyramidal tract either at the primary motor cortex or at the cerebral crus (pedunculotomy).
A
reconstruction of a pyramidal cell. Soma and dendrites are labeled in
red, axon arbor in blue. (1) Soma, (2) Basal dendrite, (3) Apical
dendrite, (4) Axon, (5) Collateral axon.
One of the main structural features of the pyramidal neuron is the conic shaped soma, or cell body, after which the neuron is named. Other key structural features of the pyramidal cell are a single axon, a large apical dendrite, multiple basal dendrites, and the presence of dendritic spines.
Apical dendrite
The
apical dendrite rises from the apex of the pyramidal cell's soma. The
apical dendrite is a single, long, thick dendrite that branches several
times as distance from the soma increases and extends towards the
cortical surface.
Basal dendrite
Basal
dendrites arise from the base of the soma. The basal dendritic tree
consists of three to five primary dendrites. As distance increases from
the soma, the basal dendrites branch profusely.
Pyramidal cells are among the largest neurons in the brain. Both
in humans and rodents, pyramidal cell bodies (somas) average around
20 μm in length. Pyramidal dendrites typically range in diameter from
half a micrometer to several micrometers. The length of a single
dendrite is usually several hundred micrometers. Due to branching, the
total dendritic length of a pyramidal cell may reach several
centimeters. The pyramidal cell's axon is often even longer and
extensively branched, reaching many centimeters in total length.
Dendritic spines receive most of the excitatory impulses (EPSPs) that enter a pyramidal cell. Dendritic spines were first noted by Ramón y Cajal in 1888 by using Golgi's method.
Ramón y Cajal was also the first person to propose the physiological
role of increasing the receptive surface area of the neuron. The greater
the pyramidal cell's surface area, the greater the neuron's ability to
process and integrate large amounts of information. Dendritic spines are
absent on the soma, while the number increases away from it.
The typical apical dendrite in a rat has at least 3,000 dendritic
spines. The average human apical dendrite is approximately twice the
length of a rat's, so the number of dendritic spines present on a human
apical dendrite could be as high as 6,000.
Growth and development
Differentiation
Pyramidal specification occurs during early development of the cerebrum. Progenitor cells are committed to the neuronal lineage in the subcortical proliferative ventricular zone (VZ) and the subventricular zone (SVZ). Immature pyramidal cells undergo migration to occupy the cortical plate, where they further diversify. Endocannabinoids (eCBs) are one class of molecules that have been shown to direct pyramidal cell development and axonal pathfinding. Transcription factors such as Ctip2 and Sox5 have been shown to contribute to the direction in which pyramidal neurons direct their axons.
Early postnatal development
Pyramidal cells in rats have been shown to undergo many rapid changes during early postnatal
life. Between postnatal days 3 and 21, pyramidal cells have been shown
to double in the size of the soma, increase in length of the apical
dendrite by fivefold, and increase in basal dendrite length by
thirteen-fold. Other changes include the lowering of the membrane's resting potential, reduction of membrane resistance, and an increase in the peak values of action potentials.
Signaling
Like
dendrites in most other neurons, the dendrites are generally the input
areas of the neuron, while the axon is the neuron's output. Both axons
and dendrites are highly branched. The large amount of branching allows
the neuron to send and receive signals to and from many different
neurons.
Pyramidal neurons, like other neurons, have numerous voltage-gated ion channels. In pyramidal cells, there is an abundance of Na+, Ca2+, and K+ channels in the dendrites, and some channels in the soma.
Ion channels within pyramidal cell dendrites have different properties
from the same ion channel type within the pyramidal cell soma. Voltage-gated Ca2+ channels in pyramidal cell dendrites are activated by subthreshold EPSPs and by back-propagating action potentials. The extent of back-propagation of action potentials within pyramidal dendrites depends upon the K+ channels. K+ channels in pyramidal cell dendrites provide a mechanism for controlling the amplitude of action potentials.
The ability of pyramidal neurons to integrate information depends
on the number and distribution of the synaptic inputs they receive. A
single pyramidal cell receives about 30,000 excitatory inputs and 1700
inhibitory (IPSPs)
inputs. Excitatory (EPSPs) inputs terminate exclusively on the
dendritic spines, while inhibitory (IPSPs) inputs terminate on dendritic
shafts, the soma, and even the axon. Pyramidal neurons can be excited
by the neurotransmitterglutamate, and inhibited by the neurotransmitter GABA.
Synaptic
inputs to a Layer V Pyramidal cell in the mouse visual cortex. Each
point represents one of > 11,000 post-synaptic sites on this neuron.
Firing classifications
Pyramidal
neurons have been classified into different subclasses based upon their
firing responses to 400-1000 millisecond current pulses. These
classification are RSad, RSna, and IB neurons.
RSna
pyramidal neurons, or non-adapting regular spiking neurons, fire a train
of action potentials after a pulse. These neurons show no signs of
adaptation.
IB
IB pyramidal neurons, or intrinsically bursting neurons, respond to threshold pulses with a burst of two to five rapid action potentials. IB pyramidal neurons show no adaptation.
Molecular classifications
There
are several studies showing that morphological and electric pyramidal
cells properties could be deduced from gene expression measured by single cell sequencing. Several studies are proposing single cell classifications in mouse and human
neurons based on gene expression could explain various neuronal
properties . Neuronal types in these classifications are split into
excitatory, inhibitory and hundreds of corresponding sub-bytes. For
example, pyramidal cells of layer 2-3 in human are classified as FREM3
type and often have high amount of Ih-current generated by HCN-channel.
Function
Corticospinal tract
Pyramidal neurons are the primary neural cell type in the corticospinal tract.
Normal motor control depends on the development of connections between
the axons in the corticospinal tract and the spinal cord. Pyramidal cell
axons follow cues such as growth factors to make specific connections.
With proper connections, pyramidal cells take part in the circuitry
responsible for vision guided motor function.
Cognition
Pyramidal
neurons in the prefrontal cortex are implicated in cognitive ability.
In mammals, the complexity of pyramidal cells increases from posterior to anterior
brain regions. The degree of complexity of pyramidal neurons is likely
linked to the cognitive capabilities of different anthropoid species.
Pyramidal cells within the prefrontal cortex appear to be responsible
for processing input from the primary auditory cortex, primary
somatosensory cortex, and primary visual cortex, all of which process
sensory modalities. These cells might also play a critical role in complex object recognition within the visual processing areas of the cortex.
Relative to other species, the larger cell size and complexity of
pyramidal neurons, along with certain patterns of cellular organization
and function, correlates with the evolution of human cognition.
Memory and learning
The
hippocampus's pyramidal cells are essential for certain types of memory
and learning. They form synapses that aid in the integration of
synaptic voltages throughout their complex dendritic trees through
interactions with mossy fibers from granule cells. Since it affects the
postsynaptic voltages produced by mossy fiber activation, the placement
of thorny excrescences
on basal and apical dendrites is important for memory formation. By
enabling dynamic control of the sensitivity of CA3 pyramidal cells, this
clustering of mossy fiber synapses on pyramidal cells may facilitate
the initiation of somatic spikes. The interactions between pyramidal
cells and an estimated 41 mossy fiber boutons, each originating from a
unique granule cell, highlight the role of these boutons in information
processing and synaptic connectivity, which are essential for memory and
learning. Fundamentally, mossy fiber input is received by pyramidal
cells in the hippocampus, which integrate synaptic voltages within their
dendritic architecture. The location of prickly protrusions and the
clustering of synapses influence sensitivity and contribute to the
processing of information pertaining to memory and learning.
Researchers are investigating which part of the brain allows people to be self-aware and how people are biologically programmed to be self-aware. V.S. Ramachandran speculates that mirror neurons may provide the neurological basis of human self-awareness. In an essay written for the Edge Foundation in 2009, Ramachandran gave the following explanation of his theory:
"[T]hese neurons can not only help simulate other people's behavior but
can be turned 'inward'—as it were—to create second-order
representations or meta-representations of your own earlier brain
processes. This could be the neural basis of introspection, and of the
reciprocity of self awareness and other awareness. There is obviously a
chicken-or-egg question here as to which evolved first, but... The main
point is that the two co-evolved, mutually enriching each other to
create the mature representation of self that characterizes modern
humans."
In health
and medicine, body awareness refers to a person's ability to direct
their focus on various internal sensations accurately. Both proprioception and interoception allow individuals to be consciously aware of multiple sensations. Proprioception allows individuals and patients to focus on sensations in their muscles and joints, posture, and balance, while interoception
is used to determine sensations of the internal organs, such as
fluctuating heartbeat, respiration, lung pain, or satiety. Over-acute
body-awareness, under-acute body-awareness, and distorted body-awareness
are symptoms present in a variety of health disorders and conditions,
such as obesity, anorexia nervosa, and chronic joint pain. For example, a distorted perception of satiety present in a patient suffering from anorexia nervosa.
Human development
Bodily self-awareness in human development refers to one's awareness
of one's body as a physical object with physical properties that can
interact with other objects. At only a few months old, toddlers know the
relationship between the proprioceptive and visual information they
receive. This is called "first-person self-awareness".
By around 18 months of age, children begin to develop reflective
self-awareness, which is the next stage of bodily awareness. It involves
children recognizing themselves in reflections, mirrors, and pictures.
Children who have not obtained this stage of bodily self-awareness tend
to view reflections of themselves as other children and respond
accordingly, as if they were looking at someone else face to face. In
contrast, those who reach this level of awareness recognize that they
see themselves, for instance, seeing dirt on their face in the
reflection and then touching their face to wipe it off.
Soon after toddlers
become reflectively self-aware, they begin to recognize their bodies as
physical objects in time and space that interact and impact other
objects. For instance, a toddler placed on a blanket, when asked to hand
someone the blanket, will recognize that they need to get off it to be
able to lift it. This is the final stage of body self-awareness and is called objective self-awareness.
Non-human animals
The mirror test is a simple measure of self-awareness.
the mark test, which involves the animals spontaneously touching a
mark on their body that would have been difficult to see without the
mirror
The red-spot technique, created by Gordon G. Gallup,
studies self-awareness in primates. This technique places a red
odorless spot on an anesthetized primate's forehead. The spot is placed
on the forehead so it can only be seen through a mirror. Once the
primate awakens, its independent movements toward the spot after it sees
its reflection in a mirror are observed.
Apes
Chimpanzees
and other apes—extensively studied species—are most similar to humans,
with the most convincing findings and straightforward evidence of
self-awareness in animals.
Chimpanzees
During
the red-spot technique, after looking in the mirror, chimpanzees used
their fingers to touch the red dot on their forehead and, after touching
the red dot they would smell their fingertips. "Animals that can recognize themselves in mirrors can conceive of themselves," says Gallup.
Three elephants
were exposed to large mirrors and experimenters studied their reactions
when the elephants saw their reflections. These elephants were given
the "litmus mark test"
to see whether they were aware of what they were looking at. This
visible mark was applied on the elephants and the researchers reported
large progress with self-awareness.
Magpies
Researchers also used the mark or mirror tests to study the magpie's self-awareness. As a majority of birds are blind below the beak, Prior et al.
marked the birds' neck with three different colors: red, yellow, and
black (as an imitation, as magpies are originally black). When placed in
front of a mirror, the birds with red and yellow spots began scratching
at their necks, signaling the understanding of something different
being on their bodies. During one trial with a mirror and a mark, three
of the five magpies showed at least one example of self-directed
behavior. The magpies explored the mirror by moving toward it and
looking behind it. One of the magpies, Harvey, during several trials
would pick up objects, pose, do some wing-flapping, all in front of the
mirror with the objects in his beak. This represents a sense of
self-awareness; knowing what is going on within himself and in the
present. The authors suggest that self-recognition in birds and mammals
may be a case of convergent evolution, where similar evolutionary pressures result in similar behaviors or traits, although they arrive at them via different routes.
A few slight occurrences of behavior towards the magpie's own
body happened in the trial with the black mark and the mirror. The
authors of this study suggest that the black
mark may have been slightly visible on the black feathers. "This is an
indirect support for the interpretation that the behavior towards the
mark region was elicited by seeing the own body in the mirror in
conjunction with an unusual spot on the body."
There was a clear contrast between the behaviors of the magpies
when a mirror was present versus absent. In the no-mirror trials, a
non-reflective gray plate was swapped in the same size and position as
the mirror. There were not any mark-directed self-behaviors when the
mark was present, in color or in black. The results show that magpies understand that a mirror image represents their own body; magpies have self-awareness.
Three "types" of self-awareness
David DeGrazia identifies three types of self-awareness which animals may share with humans:
Bodily self-awareness
This allows animals to understand that they are different from the
rest of the environment. It explains why animals do not eat themselves.
Bodily-awareness also includes proprioception and sensation.
Social self-awareness
Seen in highly social animals, this awareness allows animals to interact with each other.
Introspective self-awareness
This is how animals might sense feelings, desires, and beliefs.
Cooperation and evolutionary problems
An organism can be effectively altruistic
without being self-aware, aware of any distinction between egoism and
altruism, or aware of qualia in others. It can do this via simple
reactions to specific situations that benefit other individuals in the
organism's environment. If self-awareness led to a necessity of an
emotional empathy mechanism for altruism and egoism being default in its absence, that would have precluded evolution from a state without self-awareness to a self-aware state in all social animals.
The ability of the theory of evolution to explain self-awareness can be
rescued by abandoning the hypothesis of self-awareness being a basis
for cruelty.
Psychology
Self-awareness
has been called "arguably the most fundamental issue in psychology,
from both a developmental and an evolutionary perspective."
Self-awareness theory, developed by Duval and Wicklund in their 1972 landmark book A theory of objective self awareness,
states that when we focus on ourselves, we evaluate and compare our
current behavior to our internal standards and values. This elicits a
state of objective self-awareness. We become self-conscious as objective evaluators of ourselves. Self-awareness should not be confused with self-consciousness.
Various emotional states are intensified by self-awareness. However,
some people may seek to increase their self-awareness through these
outlets.
People are more likely to align their behavior with their standards
when they are made self-aware. People are negatively affected
if they do not live up to their personal standards. Various
environmental cues and situations induce awareness of the self, such as
mirrors, an audience, or being videotaped or recorded. These cues also
increase the accuracy of personal memory.
Albert Bandura's theory of self-efficacy
describes "the belief in one's capabilities to organize and execute the
courses of action required to manage prospective situations." A
person's belief in their ability to succeed sets the stage for how they
think, behave, and feel. Someone with a strong self-efficacy, for
example, views challenges as tasks to engage in, and is not easily
discouraged by setbacks. Such a person is aware of their flaws and
abilities and chooses to utilize these qualities to the best of their
ability. Someone with a weak sense of self-efficacy evades challenges
and quickly feels discouraged by setbacks. They may not be aware of
these negative reactions and therefore, may not be prompted to change
their attitude. This concept is central to Bandura's social cognitive
theory, "which emphasizes the role of observational learning, social
experience, and reciprocal determinism in the development of
personality."
Developmental stages
Individuals become conscious of themselves through the development of self-awareness.
This particular type of self-development pertains to becoming conscious
of one's body and one's state of mind—including thoughts, actions,
ideas, feelings, and interactions with others.
"Self-awareness does not occur suddenly through one particular
behavior: it develops gradually through a succession of different
behaviors all of which relate to the self." The monitoring of one's mental states is called metacognition and is considered to be an indicator that there is some concept of the self. It is developed through an early sense of non-self components
using sensory and memory sources. In developing self-awareness through
self-exploration and social experiences, one can broaden one's social
world and become more familiar with the self.
According to Philippe Rochat, there are five levels of
self-awareness that unfold in early human development and six potential
prospects ranging from "Level 0" (having no self-awareness) advancing
complexity to "Level 5" (explicit self-awareness):
The person is unaware of any mirror reflection or the mirroring
itself; they perceive a mirror image as an extension of their
environment. Level 0 can also be displayed when an adult frightens
themself in a mirror, mistaking their own reflection as another person
just for a moment.
Level 1—Differentiation
The individual realizes the mirror is able to reflect things. They
see that what is in the mirror is of a different nature from what is
surrounding them. At this level they can differentiate between their own
movement in the mirror and the movement of the surrounding environment.
Level 2—Situation
The individual can link the movements on the mirror to what is
perceived within their own body. This is the first hint of
self-exploration on a projected surface where what is visualized on the
mirror is special to the self.
This stage is characterized by the new ability to identify self: an
individual can now see that what's in the mirror is not another person
but actually them. This is seen when a child, instead of referring to
the mirror while referring to themselves, refers to themselves while
looking in the mirror.
Level 4—Permanence
Once an individual reaches this level they can identify the self
beyond the present mirror imagery. They are able to identify the self in
previous pictures looking different or younger. A "permanent self" is
now experienced.
At this level not only is the self seen from a first person view but
it is realized that it is also seen from a third person's view. A
person who develops self consciousness begins to understand they can be
in the mind of others: for instance, how they are seen from a public
standpoint.
Infancy and early childhood
When
a human infant comes into the world, they have no concept of what is
around them, nor the significance of others around them.
During their first year they gradually begin to acknowledge that their
body is separate from that of their mother, and that they are an
"active, causal agent in space". By the end of the first year, they
additionally realize that their movement, as well, is separate from the
movement of the mother.
At first "the infant cannot recognize its own face". By the time an average toddler reaches 18–24 months, they discover themselves and recognize their own reflection in the mirror, however the exact age varies with differing socioeconomic levels and differences relating to culture and parenting.
They begin to acknowledge the fact that the image in front of them, who
happens to be them, moves; indicating that they appreciate and can
consider the relationship between cause and effect that is happening.
By the age of 24 months the toddler will observe and relate their
own actions to actions of other people and the surrounding environment.
Once an infant has gotten a lot of experience in front of a mirror,
they can recognize themselves in the reflection, and understand that it
is them.
For example, in a study, an experimenter took a red marker and put a
fairly large red dot (so it is visible by the infant) on the infant's
nose, and placed them in front of a mirror. Prior to 15 months of age,
the infant will not react to this, but after 15 months of age, they will
either touch their nose, wondering what it is they have on their face,
or point to it. This indicates that they recognize that the image they
see in the reflection of the mirror is themselves.
A mirror-self recognition task has been used as a research tool for
years, and has led to key foundations of the infant's sense/awareness of
self. For example,[] "for Piaget, the objectification
of the bodily self occurs as the infant becomes able to represent the
body's spatial and causal relationship with the external world". Facial recognitionplaces a big pivotal point in their development of self-awareness.
By 18 months of age, an infant can communicate their name to
others, and upon being shown a picture they are in, they can identify
themselves. By two years old, they also usually acquire gender
category and age categories, saying things such as "I am a girl, not a
boy" and "I am a baby or child, not a grownup". As an infant moves to
middle childhood and onwards to adolescence, they develop more advanced
levels of self-awareness and self-description.
As infants develop their senses, using multiple senses of in
order to recognize what is around them, infants can become affected by
something known as "facial multi stimulation".
In one experiment by Filippetti, Farroni, and Johnson, an infant of
around five months in age is presented with what is known as an
"enfacement illusion".
"Infants watched a side-by-side video display of a peer's face being
systematically stroked on the cheek with a paintbrush. During the video
presentation, the infant's own cheek was stroked in synchrony with one
video and in asynchrony with the other". Infants were proven to recognize and project an image of a peer with that of their own , showing beginning signs of facial recognition cues onto one's self, with the assistance of such an illusion.
Piaget
Around
school age, a child's awareness of their memory transitions into a sense
of their self. At this stage, a child begins to develop interests,
likes, and dislikes. This transition enables a person's awareness of
their past, present, and future to grow as they remember their conscious
experiences more often.
As a preschooler, they begin to give much more specific details about
things, instead of generalizing. For example, the preschooler will talk
about the Los Angeles Lakers basketball team, and the New York Rangers
hockey team, instead of the infant just stating that they like sports.
Furthermore, they will start to express certain preferences (e.g., Tod
likes mac and cheese) and will start to identify certain possessions of
theirs (e.g., Lara has a bird as a pet at home). At this age, the infant
is in what Piaget names the pre operational
stage of development. The infant is very inaccurate at judging
themselves because they do not have much to go on. For example, an
infant at this stage will not associate that they are strong with their
ability to cross the jungle gym at their school, nor will they associate
the fact that they can solve a math problem with their ability to
count.
Adolescence
One becomes conscious of one's emotions during adolescence. Most children are aware of emotions such as shame, guilt, pride, and embarrassment by the age of two, but do not fully understand how those emotions affect their life.
By age 13, children become more in touch with these emotions and begin
to apply them to their lives. Many adolescents display happiness and
self-confidence around friends, but hopelessness and anger around
parents due to the fear of being a disappointment. Teenagers feel
intelligent and creative around teachers; shy, uncomfortable, and
nervous around people they are not familiar with.
In adolescent development, self-awareness has a more complex
emotional context than in the early childhood phase. Elements can
include self-image, self-concept, and self–consciousness among other traits that relate to Rochat's final level of self awareness, however it is still a distinct concept.
Social interactions mainly separate the element of self-awareness in
adolescent rather than in childhood, as well as further developed
emotional recognition skills in adolescents.
Mental health
As
children reach adolescence, their acute sense of emotion has widened
into a meta-cognitive state in which mental health issues can become
more prevalent due to their heightened emotional and social development. Elements of contextual behavioral science involved with adolescent self-awareness, such as Self-as-Content, Self-as-Process, and Self-as-Context, can associate with mental health.
Anger management is also associated with the concept of self-awareness in teens.
Self-awareness training may reduce anger management issues and reduce
aggressive tendencies in adolescents: "Persons having sufficient
self-awareness promote relaxation and awareness about themselves and
when going angry, at the first step they become aware of anger in their
inside and accept it, then try to handle it".
Nietzsche
would point out that this affirms "the psychology of conscience... is
not 'the voice of God in man'; it is the instinct of cruelty... one of
the oldest and most indispensable elements in the foundation of
culture."
Locke does not use the terms self-awareness or self-consciousness. According to Locke, personal identity (the self) "depends on consciousness, not on substance". A person is the same
person to the extent that the person is conscious of their past and
future thoughts and actions in the same way as they are conscious of
their present thoughts and actions. If consciousness is this "thought"
which doubles all thoughts, then personal identity is only founded on
the repeated act of consciousness: "This may show us wherein personal
identity consists: not in the identity of substance, but... in the
identity of consciousness." For example, one may claim to be a reincarnation of Plato, therefore having the same soul. However, one would be the same person
as Plato only if one had the same consciousness of Plato's thoughts and
actions that he himself did. Therefore, self-identity is not based on
the soul. One soul may have various personalities.
Locke argues that self-identity is not founded either on the body
or the substance, as the substance may change while the person remains
the same. "Animal identity is preserved in identity of life, and not of
substance", as the body of the animal grows and changes during its life.
Locke describes a case of a prince and a cobbler in which the soul of
the prince is transferred to the body of the cobbler and vice versa. The
prince still views himself as a prince, though he no longer looks like
one.
This border-case leads to the problematic thought that since personal
identity is based on consciousness, and that only oneself can be aware
of one's consciousness, exterior human judges may never know if they
really are judging—and punishing—the same person, or simply the same
body. Locke argues that one may be judged for the actions of one's body
rather than one's soul, and only God knows how to correctly judge a
man's actions. Men also are only responsible for the acts of which they
are conscious. This forms the basis of the insanity defense which argues that one cannot be held accountable for acts for which they were unconsciously irrational.
In reference to man's personality, Locke claims that "whatever past
actions it cannot reconcile or appropriate to that present self by
consciousness, it can be no more concerned in, than if they had never
been done: and to receive pleasure or pain, i.e. reward or punishment,
on the account of any such action, is all one as to be made happy or
miserable in its first being, without any demerit at all."
Disorders
The medical term for not being aware of one's deficits is anosognosia,
or more commonly known as a lack of insight. Having a lack of awareness
raises the risks of treatment and service nonadherence.
Individuals who deny having an illness may be against seeking
professional help because they are convinced that nothing is wrong with
them. Disorders of self-awareness frequently follow frontal lobe damage.
There are two common methods used to measure how severe an individual's
lack of self-awareness is. The Patient Competency Rating Scale (PCRS)
evaluates self-awareness in patients who have endured a traumatic brain
injury.
PCRS is a 30-item self-report instrument which asks the subject to use a
5-point Likert scale to rate his or her degree of difficulty in a
variety of tasks and functions. Independently, relatives or significant
others who know the patient well are also asked to rate the patient on
each of the same behavioral items. The difference between the relatives'
and patient's perceptions is considered an indirect measure of impaired
self-awareness. The limitations of this experiment rest on the answers
of the relatives. Results of their answers can lead to a bias. This
limitation prompted a second method of testing a patient's
self-awareness. Simply asking a patient why they are in the hospital or
what is wrong with their body can give compelling answers as to what
they see and are analyzing.
Anosognosia
Anosognosia was a term coined by Joseph Babinski to describe the clinical condition in which an individual suffered from left hemiplegia
following a right cerebral hemisphere stroke yet denied that there were
any problems with their left arm or leg. This condition is known as
anosognosia for hemiplegia (AHP). This condition has evolved throughout
the years and is now used to describe people who lack subjective
experience in both neurological and neuropsychological cases. A wide variety of disorders are associated with anosognosia. For example, patients who are blind from corticallesions
might in fact be unaware that they are blind and may state that they do
not suffer from any visual disturbances. Individuals with aphasia
and other cognitive disorders may also suffer from anosognosia as they
are unaware of their deficiencies and when they make certain speech
errors, they may not correct themselves due to their unawareness. Individuals who suffer from Alzheimer's disease lack awareness; this deficiency becomes more intense throughout their disease.
A key issue with this disorder is that people who do have anosognosia
and suffer from certain illnesses may not be aware of them, which
ultimately leads them to put themselves in dangerous positions and/or
environments.
To this day there are still no available treatments for AHP, but it has
been documented that temporary remission has been used following
vestibular stimulation.
Dissociative identity disorder or multiple personality disorder (MPD)
is a disorder involving a disturbance of identity in which two or more
separate and distinct personality states (or identities) control an
individual's behavior at different times.
One identity may be different from another, and when an individual with
DID is under the influence of one of their identities, they may forget
their experiences when they switch to the other identity. "When under
the control of one identity, a person is usually unable to remember some
of the events that occurred while other personalities were in control."
They may experience time loss, amnesia, and adopt different mannerisms,
attitudes, speech and ideas under different personalities. They are
often unaware of the different lives they lead or their condition in
general, feeling as though they are looking at their life through the
lens of someone else, and even being unable to recognize themselves in a
mirror.
Two cases of DID have brought awareness to the disorder, the first case
being that of Eve. This patient harbored three different personalities:
Eve White the good wife and mother, Eve Black the party girl, and Jane
the intellectual. Under stress, her episodes would worsen. She even
tried to strangle her own daughter and had no recollection of the act
afterward. Eve went through years of therapy before she was able to
learn how to control her alters and be mindful of her disorder and
episodes. Her condition, being so rare at the time, inspired the book
and film adaptation The Three Faces of Eve, as well as a memoir by Eve herself entitled I'm Eve.
Doctors speculated that growing up during the Depression and witnessing
horrific things being done to other people could have triggered
emotional distress, periodic amnesia, and eventually DID. In the second case, Shirley Ardell Mason,
or Sybil, was described as having over 16 separate personalities with
different characteristics and talents. Her accounts of horrific and
sadistic abuse by her mother during childhood prompted doctors to
believe that this trauma caused her personalities to split, furthering
the unproven idea that this disorder was rooted in child abuse, while
also making the disorder famous. In 1998 however, Sybil's case was
exposed as a sham. Her therapist would encourage Sybil to act as her
other alter ego although she felt perfectly like herself. Her condition
was exaggerated in order to seal book deals and television adaptations.
Awareness of this disorder began to crumble shortly after this finding.
To this day, no proven cause of DID has been found, but treatments such
as psychotherapy, medications, hypnotherapy, and adjunctive therapies
have proven to be very effective.
Autism spectrum disorder (ASD) is a range of neurodevelopmental
disabilities that can adversely impact social communication and create
behavioral challenges (Understanding Autism, 2003).
"Autism spectrum disorder (ASD) and autism are both general terms for a
group of complex disorders of brain development. These disorders are
characterized, in varying degrees, by difficulties in social
interaction, verbal and nonverbal communication and repetitive
behaviors."
ASDs can also cause imaginative abnormalities and can range from mild
to severe, especially in sensory-motor, perceptual and affective
dimensions.
Children with ASD may struggle with self-awareness and self acceptance.
Their different thinking patterns and brain processing functions in the
area of social thinking and actions may compromise their ability to
understand themselves and social connections to others.
About 75% diagnosed autistics are mentally handicapped in some general
way and the other 25% diagnosed with Asperger's Syndrome show average to
good cognitive functioning.
It is well known that children suffering from varying degrees of autism
struggle in social situations. Scientists at the University of
Cambridge have produced evidence that self-awareness is a main problem
for people with ASD. Researchers used functional magnetic resonance
scans (FMRI) to measure brain activity in volunteers being asked to make
judgments about their own thoughts, opinions, preferences, as well as
about someone else's. One area of the brain closely examined was the
ventromedial pre-frontal cortex (vMPFC) which is known to be active when
people think about themselves.
A study out of Stanford University has tried to map out brain
circuits with understanding self-awareness in Autism Spectrum Disorders.
This study suggests that self-awareness is primarily lacking in social
situations but when in private they are more self-aware and present. It
is in the company of others while engaging in interpersonal interaction
that the self-awareness mechanism seems to fail. Higher functioning
individuals on the ASD scale have reported that they are more self-aware
when alone unless they are in sensory overload or immediately following
social exposure.
Self-awareness dissipates when an autistic is faced with a demanding
social situation. This theory suggests that this happens due to the
behavioral inhibitory system which is responsible for self-preservation.
This is the system that prevents human from self-harm like jumping out
of a speeding bus or putting our hand on a hot stove. Once a dangerous
situation is perceived then the behavioral inhibitory system kicks in
and restrains our activities. "For individuals with ASD, this inhibitory
mechanism is so powerful, it operates on the least possible trigger and
shows an over sensitivity to impending danger and possible threats.
Some of these dangers may be perceived as being in the presence of
strangers, or a loud noise from a radio. In these situations
self-awareness can be compromised due to the desire of self
preservation, which trumps social composure and proper interaction.
The Hobson hypothesis reports that autism begins in infancy due
to a lack of cognitive and linguistic engagement, which results in
impaired reflective self-awareness. In this study ten children with
Asperger Syndrome were examined using the Self-understanding Interview.
This interview was created by Damon and Hart and focuses on seven core
areas or schemas that measure the capacity to think in increasingly
difficult levels. This interview will estimate the level of self
understanding present. "The study showed that the Asperger group
demonstrated impairment in the 'self-as-object' and 'self-as-subject'
domains of the Self-understanding Interview, which supported Hobson's
concept of an impaired capacity for self-awareness and self-reflection
in people with ASD."
Self-understanding is a self description in an individual's past,
present and future. Without self-understanding it is reported that
self-awareness is lacking in people with ASD.
Joint attention (JA) was developed as a teaching strategy to help increase positive self-awareness in those with autism spectrum disorder.
JA strategies were first used to directly teach about reflected mirror
images and how they relate to their reflected image. Mirror Self
Awareness Development (MSAD) activities were used as a four-step
framework to measure increases in self-awareness in those with ASD.
Self-awareness and knowledge is not something that can simply be taught
through direct instruction. Instead, students acquire this knowledge by
interacting with their environment.
Mirror understanding and its relation to the development of self leads
to measurable increases in self-awareness in those with ASD. It also
proves to be a highly engaging and highly preferred tool in
understanding the developmental stages of self- awareness.
There have been many different theories and studies done on what
degree of self-awareness is displayed among people with autism spectrum
disorder. Scientists have done research about the various parts of the
brain associated with understanding self and self-awareness. Studies
have shown evidence of areas of the brain that are impacted by ASD.
Other theories suggest that helping an individual learn more about
themselves through Joint Activities, such as the Mirror Self Awareness
Development may help teach positive self-awareness and growth. In
helping to build self-awareness it is also possible to build self-esteem
and self acceptance. This in turn can help to allow the individual with
ASD to relate better to their environment and have better social
interactions with others.
Schizophrenia is a chronic psychiatric illness characterized by
excessive dopamine activity in the mesolimbic tract and insufficient
dopamine activity in the mesocortical pathway, leading to symptoms of
psychosis along with poor cognition in socialization. Under the Diagnostic and Statistical Manual of Mental Disorders,
people with schizophrenia have a combination of positive, negative and
psychomotor symptoms. These cognitive disturbances involve rare beliefs
and/or thoughts of a distorted reality that creates an abnormal pattern
of functioning for the patient. The cause of schizophrenia has a
substantial genetic component involving many genes. While the heritability of schizophrenia has been found to be around 80%, only about 40% of sufferers report a positive family history of the disorder, and ultimately the cause is thought to be a combination of genetic and environmental factors.
It is believed that the experience of stressful life events is an
environmental factor that can trigger the onset of schizophrenia in
individuals who already are at risk from genetics and age. The level of self-awareness among patients with schizophrenia is a heavily studied topic.
Schizophrenia as a disease state is characterized by severe
cognitive dysfunction and it is uncertain to what extent patients are
aware of this deficiency. Medalia and Lim (2004) investigated patients'
awareness of their cognitive deficit in the areas of attention,
nonverbal memory, and verbal memory.
Results from this study (N=185) revealed large discrepancy in patients'
assessment of their cognitive functioning relative to the assessment of
their clinicians. Though it is impossible to access one's consciousness
and truly understand what a schizophrenic believes, regardless in this
study, patients were not aware of their cognitive dysfunctional
reasoning. In the DSM-5,
to receive a diagnosis of schizophrenia, they must have two or more of
the following symptoms in the duration of one month: delusions*,
hallucinations*, disorganized speech*, grossly disorganized/catatonic
behavior and negative symptoms (*these three symptoms above all other
symptoms must be present to correctly diagnose a patient.) Sometimes
these symptoms are very prominent and are treated with a combination of antipsychotics
(i.e. haloperidol, loxapine), atypical antipsychotics (such as
clozapine and risperidone) and psychosocial therapies that include
family interventions and socials skills. When a patient is undergoing
treatment and recovering from the disorder, the memory of their behavior
is present in a diminutive amount; thus, self-awareness of diagnoses of
schizophrenia after treatment is rare, as well as subsequent to onset
and prevalence in the patient.
The above findings are further supported by a study conducted by Amador and colleagues.
The study suggests a correlation exists between patient insight,
compliance, and disease progression. Investigators assess insight of
illness was assessed via Scale to Assess Unawareness of Mental Disorder
and was used along with rating of psychopathology, course of illness,
and compliance with treatments in a sample of 43 patients. Patients with
poor insight are less likely to be compliant with treatment and are
more likely to have a poorer prognosis. Patients with hallucinations
sometimes experience positive symptoms, which can include delusions of
reference, thought insertion/withdrawal, thought broadcast, delusions of
persecution, grandiosity, and many more. These psychoses skew the
patient's perspectives of reality in ways in which they truly believe
are really happening. For instance, a patient that is experiencing
delusions of reference may believe while watching the weather forecast
that when the weatherman says it will rain, he is really sending a
message to the patient in which rain symbolizes a specific warning
completely irrelevant to what the weather is. Another example would be
thought broadcast, which is when a patient believes that everyone can
hear their thoughts. These positive symptoms sometimes are so severe to
where the schizophrenic believes that something is crawling on them or
smelling something that is not there in reality. These strong
hallucinations are intense and difficult to convince the patient that
they do not exist outside of their cognitive beliefs, making it
extremely difficult for a patient to understand and become self-aware
that what they are experiencing is in fact not there.
Furthermore, a study by Bedford and Davis
(2013) was conducted to look at the association of denial vs.
acceptance of multiple facets of schizophrenia (self-reflection,
self-perception, and insight) and its effect on self-reflection (N=26).
Study results suggest patients with increased disease denial have lower
recollection for self-evaluated mental illnesses. To a great extent,
disease denial creates a hardship for patients to undergo recovery
because their feelings and sensations are intensely outstanding. But
just as this and the above studies imply, a large proportion of
schizophrenics do not have self-awareness of their illness for many
factors and severity of reasoning of their diagnoses.
Bipolar disorder is an illness that causes shifts in mood, energy,
and ability to function. Self-awareness is crucial in those suffering
from this disease, as they must be able to distinguish between feeling a
certain way because of the disorder or because of separate issues.
"Personality, behavior, and dysfunction affect your bipolar disorder, so
you must 'know' yourself in order to make the distinction."
This disorder is a difficult one to diagnose, as self-awareness changes
with mood. "For instance, what might appear to you as confidence and
clever ideas for a new business venture might be a pattern of grandiose
thinking and manic behavior".
Issues occur between understanding irrationality in a mood swing and
being completely wrapped in a manic episode, rationalizing that the
exhibited behaviors are normal.
It is important to be able to distinguish what are symptoms of
bipolar disorder and what is not. A study done by Mathew et al. was done
with the aim of "examining the perceptions of illness in self and among
other patients with bipolar disorder in remission".
The study took place at the Department of Psychiatry, Christian
Medical College, Vellore, India, which is a centre that specializes in
the "management of patients with mental and behavioural disorders". Eighty two patients (thirty two female and fifty male) agreed to partake in the study. These patients met the "International Classification of Diseases – 10 diagnostic criteria for a diagnosis of bipolar disorder I or II and were in remission"
and were put through a variety of baseline assessments before beginning
the study. These baseline assessments included using a vignette, which
was then used as an assessment tool during their follow-up. Patients
were then randomly divided into two groups, one who would be following a
"structured educational intervention programme" (experimental group), while the other would be following "usual care" (control group).
The study was based on an interview in which patients were asked
an array of open-ended questions regarding topics such as "perceived
causes, consequences, severity and its effects on body, emotion, social
network and home life, and on work, severity, possible course of action,
help-seeking behaviour and the role of the doctor/healer". The McNemar test
was then used to compare the patients perspective of the illness versus
their explanation of the illness. The results of the study show that
the beliefs that patients associated with their illness corresponds with
the possible causes of the disorder,
whereas "studies done among patients during periods of active psychosis
have recorded disagreement between their assessments of their own
illness". This ties in to how difficult self-awareness is within people who suffer from bipolar disorder.
Although this study was done on a population that were in
remission from the disease, the distinction between patients during
"active psychosis" versus those in remission shows the evolution of
their self-awareness throughout their journey to recovery.
Plants
Self-discrimination in plants is found within their roots, tendrils and flowers that avoid themselves but not others in their environment.
Self-incompatibility mechanism providing evidence for self-awareness in plants
Self-awareness
in plants is a fringe topic in the field of self-awareness, and is
researched predominantly by botanists. The claim that plants are capable
of perceiving self lies in the evidence found that plants will not
reproduce with themselves due to a gene selecting mechanism. In
addition, vining plants have been shown to avoid coiling around
themselves, due to chemical receptors in the plants' tendrils. Unique to
plants, awareness of self means that the plant can recognise self,
whereas all other known conceptions of self-awareness involve or are
centered on the ability to recognise what is not self.
Recognition and rejection of self in plant reproduction
Research
by June B. Nasrallah discovered that the plant's pollination mechanism
also serves as a mechanism against self-reproduction, which lays out the
foundation of scientific evidence that plants could be considered as
self-aware organisms. The SI (Self-incompatibility) mechanism in plants
is unique in the sense that awareness of self derives from the capacity
to recognise self, rather than non-self. The SI mechanism function
depends primarily on the interaction between genes S-locus receptor protein kinase (SRK) and S-locus cysteine-rich protein gene (SCR).
In cases of self-pollination, SRK and SCR bind to activate SKR,
Inhibiting pollen from fertilizing. In cases of cross-pollination, SRK
and SCR do not bind and therefore SRK is not activated, causing the
pollen to fertilise. In simple terms, the receptors either accept or
reject the genes present in the pollen, and when the genes are from the
same plant, the SI mechanism described above creates a reaction to
prevent the pollen from fertilising.
Self-discrimination in the tendrils of the vine Cayratia japonica mediated by physiological connection
The
research by Yuya Fukano and Akira Yamawo provides a link between
self-discrimination in vining plants and amongst other classifications
where the mechanism discovery has already been established. It also
contributes to the general foundation of evidence of self-discrimination
mechanisms in plants. The article makes the claim that the biological
self-discrimination mechanism that is present in both flowering plants
and ascidians, are also present in vining plants. They tested this
hypothesis by doing touch tests with self neighbouring and non-self
neighbouring pairs of plants. the test was performed by placing the sets
of plants close enough for their tendrils to interact with one-another.
Evidence of self-discrimination in above-ground plants is demonstrated
in the results of the touch testing, which showed that in cases of
connected self plants, severed self plants and non-self plants, the rate
of tendril activity and likeliness to coil was higher among separated
plants than those attached via rhizomes.
Theater also concerns itself with other awareness besides
self-awareness. There is a possible correlation between the experience
of the theater audience and individual self-awareness. As actors and
audiences must not "break" the fourth wall in order to maintain context, so individuals must not be aware of the artificial, or the constructed perception of his or her reality.
This suggests that both self-awareness and the social constructs
applied to others are artificial continuums just as theater is.
Theatrical efforts such as Six Characters in Search of an Author, or The Wonderful Wizard of Oz, construct yet another layer of the fourth wall, but they do not destroy the primary illusion.
Science fiction
In science fiction, self-awareness describes an essential human property that often (depending on the circumstances of the story) bestows personhood onto a non-human. If a computer, alien
or other object is described as "self-aware", the reader may assume
that it will be treated as a completely human character, with similar
rights, capabilities and desires to a normal human being. The words "sentience", "sapience" and "consciousness" are used in similar ways in science fiction.
