Clinical Neuroscience Chapter 14 Flashcards

Define emotions

Transient physiologic, cognitive, and behavioral outputs that
constitute adaptive responses to survival-relevant or otherwise
salient stimuli

Define Mood

Term used to characterize the predominant emotional state over time.
They interact bidirectionally with emotional responses to particular stimuli

What two categories can emotions be divied into?


What elicits negative emotions, and what do these stimuli lead to?

Danger, pain, or other noxious conditions
Generally lead to avoidance, escape, or protective responses

What elicits positive emotions, and what do these stimuli lead to?

Food, safety, comfort, or reproductive opportunities
Generally lead to approach behaviors

What is the primary function of emotion processing circuits in the brain?

To appraise the valance and potency of stimuli and activate
appropriate responses

Different emotions utilize distinct circuits involving limbic
structures, frontal regions of cortex, and the hypothalamus


Appraisal of a stimulus requires that highly processed sensory and
cognitive information from the association cortex gain access to
emotion processing circuits, which then activate adaptive
"downstream" responses
What do these downstream responses include?

Stimulation of arousal and attention - mediated via activation of
monoamine, cholinergic, and other widely distributed neurotransmitter
systems in the brain - as well as by activation of the autonomic
nervous system and certain neuroendocrine systems

Strong emotion suppresses ongoing behaviors in favor of automatic
defensive or approach behaviors - additionally experienced encoded
under the influence of strong emotions lead to:

Experiences encoded under the influence of strong emotions lead to
the enhancement of diverse types of memory processes to make
subsequent responses to similar stimuli maximally efficient

How can fear be roughly divided? (2 categories)

Innate fear
Learned (conditioned) fear

Information about threatening stimuli is transmitted from:

The sensory thalamus and sensory and association areas of the
cerebral cortex to the lateral nuclear complex of the amygdala (the
amygadala's major input nuclei)
- Information is processed and sent by both direct and indirect
routes to the central nucleus (the major output nucleus of the amygdala)

When presented with the same fearful stimuli (that isn't painful),
the afear response (signal elevation in amygdala) does this over time:


What mediates activation of the sympathetic nervous system?

Projections to the lateral hypothalamus

What induces the synthesis and release of corticotropin-releasing
factor (CRF)

Projections to the paraventricular nucleus (PVN) of the hypothalamus

The release of CRF activates a cascade that ultimately leads to what?

The release of glucocorticoids from the adrenal cortex

Glucococorticoids cause the body to:

Enter a catabolic state, suppress inflammatory responses and heighten arousal

In depression, this axis often becomes hyperactive

The hypothalamic-pituitary-adrenal (HPA) axis

This can supress pain in response to intense fear and stress

Projections from the amgydala to the periaqueductal gray matter (PAG)
in the core of the brainstem activate descending analgesic responses
that involve endogenous opioid peptides

Projections to the noradrenergic locus ceruleus, the serotonergic
raphe nuclei, and the dopaminergic ventral tegmental area do what?

Increase arousal and vigilance and enhance the formation of explicit
and implicit memories of circumstances under which danger has occurred

How is anxiety different from fear?

Anxiety, unlike fear, is triggered in the absence of an immediately
threatening stimulus

What may be the underlying cause of the generalized symptoms of anxiety?

The BNST - the bed nucleus of the stria terminalis
- Considered an extended region of the amygdala, and resembles the
central nucleus with regard to its cellular organization
May respond to less specific stimuli than the central nucleus and
have anxiety-like behaviors induced through CRF in this region

Memories produced by fearful situations have a cognitive and an
emotional component. What brain structure seems to be predominant in
each what do these brain structures do?

Cognitive - Hippocampus
- Records the precise setting in which danger was experienced and
details of the experience
Emotional - Lateral nuclear complex of the amygdala
- Activates physiologic and behavioral responses to danger when
learned predictors of danger are encountered (autonomic responses)

The enhanced memories associated with strong emotion seem to depend
on what receptors?

Beta-adrenergic receptors in the amygdala, which then interacts
strongly with the hippocampus
- This enhancement can be blocked by Beta-adrenergic receptor
antagonists such as propranolol administered prior to certain stages
of memory consolidation

If propranolol can efficiently and effectively reduce traumatic
memories to the level of ordinary memories without causing amnesia, it
may be effective against this disorder:


Positive emotional experiences also promote memory. Under normal
circumstances these memories produce reinforcement in response to
natural rewards such as food, safety, and mating opportunities.
Abnormal stimulation of reward circuitry however may be a central
cause of this:


Accumulated data suggest that circuits involved in mood regulation
and mood disorders include the

Orbital and medial F=PFC, the cingulate gyrus, the amygdala, ventral
striatum, hippocampus, and hypothalamus

Anxiety and mood disorders seem to have shared

Genetic risk factors

This brain area has been implicated in depression and may monitor
performance for signs of failure, just as the amygdala monitors
sensory inputs for signs of threat

The anterior cingulate gyrus (the subgenual cingulate cortex) AKA
Brodadmann area 25

For patients with unrelenting major depression, for whom other
therapies have not been successful, 2/3 of them have had sustained
improvement from this treatment

DBS in the subgenual cingulate cortex

The current categorization of anxiety and mood disorders is based on

Exclusively syndromal groupings of subjective and behavioral symptoms

Hyyperactivity of this brain area has been associated with PTSD in
PET and fMRI scans

The amygdala

Overall it appears that patiens with certain anxiety disorders
exhibit this in thier brain circuitry:

Hyperresponsiveness of amygdala-based fear circuitry and decreased
activity of medial and orbital prefrontal cortical regions that
normally serve to suppress fear and anxiety

Provide the treatments used for the following conditions:
- Acute anxiety
- Generalized anxiety disorder
- Panic disorder


Benzodiazepines bind here:

The alpha subunit of GABAa receptor complex, increasing the affinity
of the beta subunit for GABA

This drug, an inverse agonist of the benzodiazepine binding site on
the GABAa receptor alpha subunit, is proconvulsant and proconflict

Beta-CCE or Beta-carboline

Benzodazepines are a class of drugs with what properties?

Anxiolytic, sedative, muscle relaxant, and anticonvulsant properties.
- They produce anterograde amnesia

Anticonvulsant actions of benzodiazepines are believed to occur in the:

Cerebral cortex, hippocampus, or amygdala

Barbituates do this to Cl- channels

Increase the probability that they will open and the duration of
their opening

Barbituates can act ______ of GABA, leading to a far greater
inhibition of the nervous system than can benzodazpeines

- Increases risk of serious respiratory depression and death when overdosed

Because ethanol facilitates the GABA-mediated opening of GABAa
receptor Cl- channels, this is among the most prominent effects of ethanol:

A reduction in anxiety

What may explain actue tolerance?

Covalent modification of the GABAa receptor by phosphorylation

Longer-term tolerance and dependence may be explained by:

Altered expression of GABAa receptor subunits leading to altered
receptor levels

Describe buspirone

An azaspirodecanedione marketed as an anxiolytic
A partial agonist at 5HT1a serotonin receptors
- Approved for use in the treatment of generalized anxiety disorder,
but isn't very effective
- Virtually without abuse libability

What role does adenosine play in anxiety?

It is a purine neurotransmitter that inhibits the release of ACh, NE,
gluatamte, DA, 5Ht, and GABA in specific regions of the brain through
actions at its A1 receptors.
- Mediated through the opening of K+ channels, inhibition of Ca2+
channels opening, and the inhibition of adenylyl cyclase
Adenosine is sedative, anticovulsant, analgesic, and anxiolytic