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Limbic by Bibb
Question | Answer |
---|---|
Describe the connections of the Papez circuit. | mammillary bodies -- anterior nucleus of thalamus -- cingulate gyrus -- hippocampus -- mammillary bodies via fornix |
Name 4 other structures now thought to be included in Papez circuit. | orbital/medial prefrontal cortex, ventral basal ganglia (nucleus accumbens), amygdala and dorsomedial nucleus of thalamus |
hypothalamus' function with regard to limbic system | coordination of somatic (extrapyramidally) and autonomic components to integrate emotional behavior |
experiment by Cannon and Bard - cats with transected brains but caudal hypothalamus left intact | autonomic and somatic manifestatsions of sham rage, display of emotions don't necessarily require the cortex |
the major target location of newly produced neurons | hippocampus receives most products of neurogenesis to allowed continual formation of declarative (episodic memory) |
major inputs of the hippocampus | entorhinal cortex and cholinergic projections from medial septal nucleus & nucleus of the diagonal band of Broca via fornix fibers |
the specific portion of the hippocampus involved in the Papez circuit | subiculum |
outputs of the hippocampus | subiculum out to mammillary bodies, septal nuclei, anterior and dorsomedial nuclei of thalamus |
What happened to HM when his bilateral medial temporal lobes were removed? | ability to form new episodic memories was devastated |
True/False: There is a complete loop between the entorhinal cortex and hippocampus. | true: input from entorhinal to hippocampus AND output from hippocampus to entorhinal cortex, which then goes to other cortical areas |
location of the amygdala | anterior medial temporal lobe, rostral to the hippocampus |
3 major divisions of the amygdala | basolateral, central and medial (corticomedial) nuclei |
the division of the amygdala important for attaching emotional significance to stimuli | basolateral nucleus |
input and output of basolateral nucleus of amygdala | input: higher order sensory cortices (orbital, medial prefrontal, temporal, insular and association) output: back to orbitofrontal and temporal cortices, cingulate gyrus and hippocampus, basal nucleus of Meynert, amygdala and thalamus |
division of amygdala important for mediating emotional responses | central nucleus |
input and output of central nucleus of amygdala | input: viscerosensory from brainstem, basolateral nucleus output: autonomic nuclei, periaqueductal gray, hypothalamus, reticular formations |
division of amygdala that may be important for food intake, reprod. behavior and/or behaviors influenced by smell | medial (corticomedial) nucleus |
input and output of medial nucleus of amygdala | input: olfactory structures output: VM nucleus of hypothalamus via stria terminalis, olfactory structures |
symptoms of Kluver-Bucy syndrome seen in Rh monkeys after removal of temporal lobes including amygdalas | placidity (lack of fear responses), hyperorality, hypersexuality |
function of the anterior cingulate gyrus | initiation, motivation and goal-directed behavior. affect division: modulating autonomic activity and emotional response. cognitive division: frontal executive functions |
function of the posterior cingulate gyrus | visospatial processing and memories of what we have seen |
lesions of the cingulate gyrus cause? | abulia, akinetic mutism, decreased response to pain, impaired social behavior (almost like depression) |
lesions of the orbital frontal cortex cause? | risk-taking behavior, failure to learn from mistakes, poor judgment and lack of empathy, can't plan ahead or reason (Phineas Gage) |
connections of the orbital frontal cortex? | bidirectional with amygdala and dorsomedial nucleus of thalamus via ventral basal ganglia |
major excitatory NT of the limbic system | glutamate |
the age when memories first start to be consolidated much better due to a large increase in the # of synaptic connections in the brain | 3 y/o |
the type of neurotransmission that regulates the excitability of fast ionotropic synapses | slow or metabotropic neurotransmission via GPCRs |
function of monoamines in the limbic system | mediate metabotropic neurotransmission to regulate excitability of circuits involved in memory formation |
A person with major depressive disorder would show abnormal metabolic activity in which brain areas? | thalamus, basal ganglia, frontal cortex |
Without these ions/molecules, recording and experiencing memories is not possible. | calcium and cAMP |