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Transcript
COGNITIVE SCIENCE 175
Spring Quarter
Midterm I
Answer only 4 of the questions. Each is worth 25 points. Make sure to
write your name at the top of each page. Don’t forget to provide
examples from class readings.
1. Is hypnosis a distinct state of consciousness? Why or why not? What
are the behavioral correlates of hypnosis (i.e., how is a hypnotic state
defined behaviorally)? What are some of its neural substrates?
Hypnosis is a distinct state of consciousness. In a hypnotic state
people process information differently, interact with the environment
differently and have different representations of themselves and of the
world when compared to a normal state of awareness. Under hypnosis it
has been reported that bad habits can be treated, phobias can be
overcome, and the sensation of pain can be regulated. According to the
trance theory of hypnosis, people enter an altered trance-like state in
which they are highly susceptible to suggestion. Other theories,
specifically the sociological and task-motivation theories argue that
one’s willingness to play a role and eagerness to please are what
characterizes hypnosis as not being an altered state of consciousness.
Behavioral correlates of hypnosis are best summed up by Price’s
dimensions of this state: 1) increased mental relaxation 2) increased
mental absorption 3) decreased tendency to judge 4) loss of time,
orientation, and sense of self 5) automatic or extravolitional responses.
In general, people under hypnosis are extremely relaxed, have focused
attention, and are very open to suggestion.
Faymonville and Rainville have shown that there are neural
substrates underlying these behavioral phenomena. In studies on
nociception, Faymonville argued that the midcingulate cortex has
enhanced neuromodulatory activity that reduces the perception of pain
under hypnosis. In a network including somatosensory cortex, the
thalamus and the brainstem, the midcingulate cortex increases inhibition
of pain. Rainville showed support for the same structures underlying the
relaxing and attentional processes under hypnosis. Decreased rCBF in
the thalamus and the brainstem correlates with increased relaxation.
Ascending cholinergic pathways controlling sleep and wakefulness may
be involved. In other parts of the thalamus and in the upper pons,
increased rCBF correlates with highly focused attention. In light of these
studies and the observations of hypnotized people, hypnosis is clearly a
distinct state of consciousness.
2. The role of dopamine in the concept of reward and drug addiction has
changed significantly during the last few years to one based more on
changes in cognitive processes. Discuss this new view and its
significance to alternate states of consciousness.
In the “new view” on dopamine reward and drug addiction,
dopamine is still associated with reward and motivation but a new
emphasis is also put on dopamine’s role in processing saliency. Drug
addiction affects reward and saliency in the following ways: when a
drug is first administered, there is a large amount of DA released by the
nucleus accumbens – a much larger amount than is released in natural
reward situations (i.e., eating cheesecake). Despite this initial high level
of DA, long-term drug use actually results in a decrease in total
dopamine production as well as a decrease in D2 receptors. This means
that natural reinforcers (like cheesecake, everyday achievements, etc),
which do not result in as much DA output as the drug, are no longer
rewarding/salient. In addition, the drug itself takes on increased
saliency. Furthermore, drug-induced changes in frontal cortex and the
cingulate result in inability to inhibit behavior, which means that the
person will continue to use the drug even though they are cognitively
aware of the negative consequences this may entail (for example, going
to jail). People who naturally have lower D2 receptor levels will find
drugs more salient/rewarding and are more likely to use them, while
people with higher D2 levels experience unpleasant overstimulation as a
result of the DA released in drug use. There are several implications for
ASC’s:
1) The same stimulus can affect different people’s conscious
experience differently depending on their brain structure, which
implies there is individual variation in consciousness;
2) 2) ASC’s are associated with changes in the brain’s synaptic
structure and neurochemical balance as well as with
behavioral changes.
3. How would you reconcile the following observations: “Alternate
states of consciousness (ASCs) are principally due to frontal cortex
activity. However, a large body of evidence from lesion, imaging,
and electrophysiological studies suggests that the prefrontal cortex is
not necessary for basic awareness. In contrast, lesions to various
brainstem nuclei or the intralaminar nuclei of the thalamus result in
the loss of awareness.”
This observation can be reconciled by Dietrich’s theory of a
hierarchically organized consciousness. He believes that prefrontal
cortex plays an important role in consciousness, but that consciousness is
a phenomenon that involves the whole brain. Dietrich’s theory is based
on evolutionary factors. Thus our primitive brain, such as the midbrain
and hindbrain, are lower in the hierarchy and the cortex and its lobes
(temporal, occipital, frontal, parietal) are higher in the hierarchy.
Dietrich claims that all regions of the brain contribute to a person’s
consciousness, but not all regions contribute equally. He claims
prefrontal cortex is important because it is implicated for phenomena
such as memory, planning, theory-of-mind, attention, social interaction
and other higher-order functions which make a person “conscious.”
Basic awareness, on the other hand, is at a lower level of the hierarchy.
So, the lower down you go (in terms of damaging a region) the more you
are fundamentally going to affect awareness and more basic, primitive
functions like it. Consciousness is based higher on the hierarchy with the
prefrontal cortex contributing a vast amount and the other lobes
contributing as well. Thus, althougnh prefrontal cortex is not
responsible for basic awareness, it is involved in this higher-order
concept of consciousness and alternate states. Diff alternate states are
simply caused by different activation and circuits in the frontal lobe.
4. Discuss what might be the relationship between ASCs and periods of
synchronous activity represented by certain electric potential patterns
on the scalp.
Alternate states can be thought to relate to electrical rhythms found
on the scalp (in addition to the anatomical and neurochemical
descriptions discussed earlier). These different frequencies appear to
relate to different mental states and cognitive functions. According to
Pineda, the mu rhythm is an alpha-type rhythm found primarily above
motor cortices and correlates to motor action, observation and thought
in the individual. According to Vernon, the theta rhythm is a slow
rhythm which correlates with working memory and the SMR is found
over sensorimotor areas and correlates with attention. Theta rhythms
have also been implicated in “internal” states and processes such as
meditation or deep contemplation. Because of the cognitive implications
of these brain rhythms, it is reasonable to conclude that ASC’s may be
modulated by increases or decreases of certain rhythms w/in certain
areas of the brain. This may actually validate or support some of the
anatomical research that rhythm generators correspond to defined areas
in the brain.
5. Discuss what makes individuals more or less susceptible to different
methods that create distinct states of consciousness (i.e., drugs,
hypnosis, biofeedback). What might be the similarities or differences
across the various ASCs.
Individuals may be more susceptible to different methods of altering
consciousness for many reasons. Hypnosis, for example, works best on
highly suggestive people, there is even a standardized test to determine
susceptibility called the Stanford Susceptibility Test, which can determine
level of suggestiveness based on answers to particular questions.
Biofeedback also involves using individuals who are more likely to
respond, such as highly attentive individuals. I feel that attention plays
the largest role in determining susceptibility due to William James’
definition of alternate states of cons. He suggests that there is a selective
filter of consc. In hypnosis, the task-motivational theory suggests that
hypnosis occurs only because the individuals are simply choosing to
attend to what the hypnotist is saying. So there is a high level of
attention involved. In biofeedback, as well, the individuals are simply
choosing to focus all attentional resources on certain inward functions,
thus being able to alter their state internally. With drugs, however, I
don’t believe that attention plays a big role. Individuals may have a
propensity toward drug addiction due to many factors, however, mainly
either social factors or possible family history of addiction, which
suggests a gene mutation. So I feel that both hypnosis and biofeedback
susceptibility depends mainly on an individual’s ability to focus
attentional resources to enter an alternate state of consciousness. But,
drug addiction depends more on neural organization and social
propensity.