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CHAPTER 15
Sleep and
Consciousness
The Neural Bases of Consciousness
Sleep issues and disorders
• Insomnia
– inability to sleep or to obtain adequate quality sleep
– Must occur to the extent that the person feels inadequately rested.
• Insomnia can be brought on by a number of factors,
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Stress.
Health issues
Lack of physical activity
Over-medicaton or medication interactions
Occurs frequently in people with psychological problems, especially affective
disorders.
• May tie in with weight gain and obesity: people with insomnia show
– Waking release of hypocretin or orexin
– Lower levels of leptin and higher ghrelin levels
– Orexigenic or appetite enhancing effect
insomnia
• Many manifestations:
– Delayed sleep onset
– Nighttime waking
– Early waking
• Disruption of circadian rhythm often is cause
– Normally: body temp decreases as fall asleep
– If body temp still high at bedtime, takes longer or is more
difficult to fall asleep
– If rises too early- wake up early
Insomnia disorders
• Two mutations in circadian clock genes identified with
insomnia:
– Advanced sleep phase syndrome: early onset of sleep,
early waking
• Chronotype: internal clock synchronized to 24-hour day, but
depends on environment as well
• Are you a lark or an owl?
– Delayed sleep syndrome:
• Obviously, delayed getting to sleep
• Often not going to bed until wee hours of morning
• Treatment: stay up three hours later each day, until
completely reset clock!
Narcolepsy
• Individuals fall asleep suddenly during the daytime : go directly into REM
sleep.
• Cataplexy
– sudden experience of one component of REM sleep – atonia –
– falls to the floor paralyzed but fully awake.
• Not that sleep more, but “boundaries” between sleep and wakefulness are
disrupted- have sudden shifts
• Why? Mutated HLA-DQ6 gene that is responsible for hypocretin receptor
function
– Have low or undetectable levels of hypocretin, due to loss of hypocretin secreting
neurons in hypothalamus
– Also an HLA-DR15 gene mutation
• Treatment: stimulants; but targeting hypocretin would work better!
Sleep walking
• Some sleep disorders, such as sleep walking, related to specific
sleep stages (particularly stage 3).
– E.g., Bedwetting, night terrors, and sleep walking occur
during slow wave sleep.
– Although sleepwalking most frequent in childhood, about
3-8% of adults sleepwalk.
• Sleepwalking
– at least partially genetic
– Can be triggered by stress, alcohol, and sleep deprivation
REM SLEEP DISORDER
• REM sleep behavior disorder
– Individuals uncharacteristically physically active during REM sleep,
– Often injure themselves or their bed partners.
– Often associated with a neurological disorder, such as Parkinson’s
disease or a brain stem tumor.
• Why? Lewy bodies found in up to 2/3 patient’s brains
– abnormal aggregates of protein that develop inside nerve cells
– Inhibition of magnocelluar nucleus that normally produces atonia
during sleep
– Suggest that Parkinsons, brain tumors, and related disorders
preceded by development of Lewy bodies in medulla
• Sleep disturbances may be “soft” sign of these disorders
– As disease progresses, Lewy bodies progress up into higher brain
areas
Consciousness
Is this just being awake?
Is this being aware?
Does this involve thinking?
The Neural Bases
of Consciousness
• Consciousness
– refers to a state: A person is conscious or unconscious.
– The term also used to indicate sense of conscious experience, or
awareness of something.
– Consciousness involves short-term memory,
• Fully conscious humans have a sense of self,
– requires long-term memory.
• Consciousness varies in level
– coma and deep anesthesia on one extreme
– alert wakefulness on the other, and sleep in between.
Glasgow Coma Scale
Eyes
1
Does not
open eyes
Verbal
Makes no
sounds
Motor
Makes no
movements
2
Opens eyes in
response to
painful stimuli
Incomprehensible
sounds
Extension to
painful stimuli
(decerebrate
response)
Generally, brain injury is classified as:



Severe, with GCS ≤ 8
Moderate, GCS 9 - 12
Minor, GCS ≥ 13
3
Opens eyes
in response
to voice
Utters
inappropriate
words
Abnormal
flexion to
painful
stimuli
(decorticate
response)
4
5
Opens eyes
N/A
spontaneously
6
N/a
Confused,
disoriented
N/A
Flexion /
Withdrawal to
painful stimuli
Oriented,
converses
normally
Localizes
painful
stimuli
Obeys
commands
The Neural Bases
of Consciousness
• Three critical components of consciousness
– Awareness
– Attention
– Sense of self.
• Altered states of consciousness include
– hypnosis
– trances
– meditative states
awareness
• Awareness:
– Abstract concept
– Difficult to define, more difficult to study.
– Researchers focused on awareness of something.
• Prefrontal cortex appears to be key player in producing
awareness.
– May also involve hippocampus
– Hippocampus critical for declarative learning
– Declarative learning, by definition, involves awareness.
• Also Parietal lobes:
– ability to locate those objects in space which are necessary for
combining features of an object into a conscious whole.
Binding problem
• Issue of how the brain combines information from different
areas into a unitary whole: how integrate all the incoming
information
• Brain must bind information from one area to another
• Numerous studies suggest: synchronization of activity across
brain areas binds various elements of perception into a
coherent cognitive experience.
– Forming neural networks
– Networks must be linked to other networks, forming larger
networks
– Quickly goes beyond our computational ability to work with this.
Experimental evidence
for binding
• Light paired several times with
shock to the middle finger:
– CSL  USshock
• Light alone produces
synchronized firing between
visual cortex and
somatosensory cortex where
fingers represented.
• Synchrony occurs in right
hemisphere when shock
applied to left hand
• Synchrony occurs in left
hemisphere when shock
applied to right hand
attention
• Attention: Brain’s means of allocating limited resources = focusing
on some neural inputs to the exclusion of others.
– Is a physiological process
– Changes in attention accompanied by changes in neural activity.
• When an observer attends to an object:
– Firing synchronizes between brain areas involved
– E.g., prefrontal with parietal neurons or parietal neurons with visual areas,
depending on the task.
• When attention shifts:
– E.g., during binocular rivalry
– Activity shifts from one group of neurons in the visual cortex to another
– Shifts even though stimulus inputs do not change.
Sense of self
• Critical aspect of consciousness
• The sense of self includes identity: what we refer to as “I”
– Sense of agency: attribution of an action or effect to ourselves.
• Research suggests that damage to the anterior cingulate cortex
results in diminished self awareness
• Damage to right frontal-temporal cortex may produce sense of
detachment from the self.
– Farrer and Frith et al.
– Sense of agency mediated by anterior insula and inferior parietal area.
Intriguing evidence:
• Patients like HM
– Deprived of short-term memory
– But have most of long term memories of past intact,
– Typically have a strong sense of self.
• Korsakoff’s and Alzheimer’s patients
– Extensive loss of current memories, then past memories,
– Greater impairment of their sense of self.
– Indicates that loss of LTM means loss of who you are
– Interesting: occurs in reverse order
• Forget adult self and “re-enter” childhood
• Eventually, lose all of oneself
• Like randomly tearing pages from a book until all you have left
is the cover
Why sense of self
important?
• Body image contributes to a sense of self
– We have identification with our body and with its parts
– Identify actions that are “ours” versus “not ours”
– Able to identify our thoughts/actions from those of others
.
• Without long-term memory: Doubtful there can be a self
– If there is memory, there is no past there
– If there is no past, there is no sense of who the person is
• A sense of self requires distinction between our self and other
selves
– Cannot understand other selves unless understand our
self.
– Mirror neurons appear critical to developing the ability to
attribute mental states to others (theory of mind).
Mirror neurons
• Mirror Neurons fire both when one acts and when one
observes the same action performed by another
– The neuron "mirrors" the behavior of the other, as though the
observer were itself acting.
– Identified mirror neurons in primates. Dogs, birds and several
other species
• In humans, brain activity consistent with mirror neurons found in
• Premotor cortex area
• Supplementary motor area
• Primary somatosensory cortex
• Inferior parietal cortex
Why mirror neurons?
Several theories
• System provides physiological mechanism for perception-action
coupling
• Links our actions with our perceiving of an action
• Important for understanding the actions of others
• Also for learning new skills by imitation.
• Mirror systems may simulate observed actions, and thus
contribute to theory of mind skills
– Mirror neurons critical for language abilities
– Help us understand actions and intentions of others
– The neural basis of the human capacity for emotions such as
empathy
• Problems with or absence of the a mirror neuron system may
underlie cognitive disorders, particularly autism and Williams
syndrome
Sense of self =
Integration of both hemispheres
• Scientists know that need both hemispheres working
together to develop sense of self.
• Hemispherectomy:
– Surgical procedure that separates two cerebral hemispheres
– Cut the corpus callosum.
– Used to prevent severe epileptic seizures from crossing the
midline and engulfing the other side of the brain.
• Individuals with “split brain” show interesting
differences: raise important questions about
consciousness and the self.
Split brain patients and
“self”
• Split-brain outcomes:
– language-dominant hemisphere is conscious, while other hemisphere
is non-conscious automaton.
– But: each hemisphere capable of consciousness,
– Thus severing the corpus callosum divides consciousness into two
“selves”.
• Gazzaniga : Left hemisphere contains module that serves as
“brain interpreter.”
– integrates all cognitive processes going on simultaneously in other
modules of the brain
– If not have both hemispheres intact, brain interpreter cannot function
normally.
Dissociative identity
disorder
• Dissociative identity disorder
– (Formerly known as multiple personality)
– Disorder of the self
– Involves shifts in consciousness and behavior that appear to be distinct
personalities or selves.
– Causes of this disorder are not understood,
• Appears to be related to abuse
• 90 to 95% of patients report childhood physical and/or sexual abuse.
• Individual creates alternate personalities (“alters”) as a
defense against persistent emotional stress.
– The alters provide escape
– Also offers opportunity to engage in prohibited forms of behavior.
– Suggests that under stress brain can isolate “memories” to protect the
major “self”
So what is consciousness? ?
• Most neurobiological theories of consciousness assume that
consciousness requires widely distributed neuronal network.
• According to some theorists
– Consciousness occurs when functioning of widespread networks
becomes coordinated,
– Enables them to share and integrate information.
• Distribution of consciousness: Consciousness occurs
“throughout” the brain
– Means that there is no center of consciousness,
– Some researchers believe must be an executive function
• Brain integrator important
– area that coordinates or orchestrates activity of all the other structures.
Do animals show a sense of self?
• Frans deWall: ethologist who studies moral behavior
• Several studies with monkeys: do they notice and can they
compare what they get versus what others get
• Let’s take a look:
• http://www.wimp.com/moralbehavior/
Take home message
• Brain activity occurs on molecular/cellular level
– Quite complicated
– Huge amount of neurons firing at any time
• Individual cells must form networks
– Networks must work together
– Must be stable yet fluid
– Forms basis of “memories” throughout the brain
• No “centers” in brain
– Redundancy, redundancy, redundancy
– Duplication of centers; multiple mechanisms control similar
behaviors
– Allows neuroprotection
Take home message
• Only when brain networks “work together” in elaborate,
coordinated and consistent way do we become a “person”
– Damage alters who we are, what we are
– But who we are is evolving and changing as our brain changes
• If we don’t use a process/function, there is a danger we
could lose it!
• We only have one brain: use it wisely, protect it, and
respect it!
FINAL Take home message
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So why do psychology majors have to take this class?
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Understand
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When your client, relative, yourself has a brain disorder or injury
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You can be knowledgeable about how this might affect behavior, personality, sense of self
You can predict and then prevent or remediate issues by being knowledgeable about brain
anatomy, physiology, and the various treatments available
Most important: you become an educated consumer
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brain functions from molecular level on up
link between brain function and behavior
link between brain functions and mental illness
We argue with car repair shops, the handyman, the plumber about whether something is
necessary
We take the doctor’s recommendations without question
We need to be educated and understand what treatments are recommended and be able to
examine critically what is scientifically valid and what is bogus
Hopefully, as a result of this class, you have become an educated consumer
regarding brain function and treatments.