Memory, Limbic System Review

Front 1

Explain the mechanisms of habituation

Back 1

decreased number of quanta released
decreased strength of synaptic connection
decreased number of axonal branches (long-term habituation)

Front 2

Explain the mechanism of sensitization

Back 2

interneuron releases serotonin (or other neuromodulator) onto sensory neuron, sensory neuron becomes more excitable through g-protein coupled action, leads to more glutamate released

Front 3

What is the role of CA1 pyramidal neurons in long-term potentiation? (mechanisms)

Back 3

NMDA channels (that open with high frequency train) allow Ca to enter cell, which causes persistent enhancement of synaptic transmission;
structural changes to presynaptic neuron make transmission more efficient

Front 4

What is the relationship between LTP and spatial learning?

Back 4

both are mediated by NMDA-dep. processes

Front 5

What are the mechanisms by which CA1 neuron activity is increased with conditioning?

Back 5

reduction in hyperpolarizing Ca current makes neurons more excitable;
increased number of synaptic boutons on CA1 dendrites

Front 6

What is declarative memory?

Back 6

explicit memory of one's own experiences, object recognition

Front 7

What is procedural memory?

Back 7

Skilled movements, priming, habituation, simple associative learning

Front 8

Explain the pathway of hippocampal based memory from neocortex and back

Back 8

preprocessed info in neocortex - entorhinal/parahippocampal cortices - hippocampus (dentate gryus - CA3 - CA1) - subiculum (part of cortex) - entorhinal/parahippocampal cortex - neocortex

Front 9

What is the role of the medial septum in hippocampal memory?

Back 9

releases ACh and GABA on hippocampus
triggers theta rhythm in hippocampus (involved in exploration and plasticity)

Front 10

What are the two projections sites of the subiculum?

Back 10

entorhinal/parahippocampal cortices (basis of permanent memory consolidation)
forebrain structures via fimbria/fornix

Front 11

What key about memory do we learn from HM?

Back 11

Different types of memory uses different mechanisms, different anatomy
hippocampus important for short-term memory, unnecessary for mirror drawing and incomplete figure tasks

Front 12

What key about memory do we learn from RB?

Back 12

loss of CA1 neurons leads to deficits that are very similar to HM's, who lost hippocampi and amygdalas

Front 13

What does the left hippocampus specialize in? Right hippocampus?

Back 13

Left hippocampus: verbal memory
Right hippocampus: visual memory

Front 14

Why are the CA1 neurons so important for spatial learning tasks?

Back 14

CA1 neurons demonstrate "spatial fields" that fire when the organisms is at a specific location in space

Front 15

What do the London taxi drivers show?

Back 15

posterior hippocampus grows with more taxi driving (spatial learning)

Front 16

Describe the hippocampal system anatomy (of the limbic system)

Back 16

hippocampus connects to mammillary bodies and anterior thalamus via fornix; anterior thalamus connects to cingulate/parahippocampal cortex; mamillary bodies connect to anterior thalamus and septal area --> brainstem and spinal cord

Front 17

Describe the amygdaloid system anatomy (of the limbic system)

Back 17

Amygdala connects to dorsomedial thalamus and septal area/hypothalamus via stria terminalis --> brain stem and spinal cord; dorsomedial thalamus projects up to prefrontal cortex and anterior temporal cortex; amygdala also projects to other nuclei associated with autonomic activity

Front 18

What does the septum do?

Back 18

"meeting place of the limbic system"
connects preoptic area and hypothalamus, source of ACh and GABA, triggers theta rhythm in hippocampus

Front 19

What are the two major groups within the amygdala, and what projects to them?

Back 19

Cortical medial group: olfactory bulbs, septal region, hypothalamus
Basolateral group: visceral and taste afferents, sensory inputs from insular and temporal cortex

Front 20

What is a possible mechanism for how sensation and memory acquire emotional tone?

Back 20

Basolateral group of the amygdala projects back onto higher order sensory cortices

Front 21

What structures make up the basis of fear conditioning?

Back 21

Amygdala for emotional response
Hippocampus for declarative information

Front 22

What is the result of unilateral (or bilateral) amygdalar lesion?

Back 22

deficit in fear conditioning

Front 23

Explain the subset of older individuals that performs as well or better than younger subjects in cognitive tasks

Back 23

"survival of the fittest" generates long-living, healthy-brain group of old subjects

Front 24

What are the 3 key observations in standard mental decline during aging

Back 24

slower reaction times
loss of attention and working memory (decreased ability to gate irrelevant info)
poor learning and memory ability

Front 25

Describe the findings of restricted-calorie diets in mice

Back 25

extended lifetimes, presumably due to decreased buildup of free radicals, leading to less mitochondrial damage

Front 26

What is the effect of exercise on the hippocampus?

Back 26

exercise boosts brain-derived neurotrophic factor (BDNF), increases cognitive function

Front 27

Explain the physiology of deficits seen in aging neurons (2 major things)

Back 27

decreased response ACh, leading to less synaptic input
"calcium toxicity" after prolonged stimulation

Front 28

Explain the beta-amyloid hypothesis of Alzheimer's disease

Back 28

APP proteins (help neuron survive and grow) cut inappropriately - creates beta-amyloid fibrils - fibrils aggregate into plaques - destabilizes Ca homeostasis and neurons become vulnerable to glutamate-mediated toxicity

Front 29

What are the causes of Alzheimer's disease?

Back 29

Majority of cases due to environmental causes; genetic causes can lead to Alzheimer's as early as 30-40 y/o

Front 30

What are some key neurophysical changes that occur in Alzheimer's?

Back 30

impairment of memory
learning deficits
flat affect

Front 31

What are some possible treatments for Alzheimer's?

Back 31

Increased education
anti-beta-amyloid vaccination
drugs to prevent APP cleavage
cholinesterase inhibitors - current treatment

Front 32

What are the 3 primary areas of the prefrontal cortex?

Back 32

lateral prefrontal cortex
ventromedial prefrontal cortex
anterior cingulate

Front 33

What is the general function of the prefrontal cortex? (2 things)

Back 33

temporal organization of behavior
cognitive controller of movement

Front 34

What is working memory?

Back 34

Short term memory is actively engaged in influencing cognitive processes; integration of perception and stored knowledge

Front 35

What is the key to working memory tasks like the delayed response task or the wisconsin card sorting task?

Back 35

subject must remember piece of info for an amount of time with no association cues

Front 36

2 models for the function of lateral prefrontal cortex

Back 36

temporary holding site for task-relevant long-term stored representations
visuo-spatial sketchpad (R) - central executive working memory - phonological loop (L)

Front 37

What part of the prefrontal cortex is associated with temporal tag process and source memory?

Back 37

lateral prefrontal cortex

Front 38

What happens when you get damage to the prefrontal lobes (not ventromedial in particular)?

Back 38

Inability to exclude irrelevant information or ignore present stimuli (utilization and imitative behavior)

Front 39

What is Damasio's somatic marker hypothesis, and where is the machinery housed?

Back 39

integration of affective aspects into decision-making
ventromedial prefrontal cortex

Front 40

What is the role of the anterior cingulate cortex?

Back 40

supervisory attentional system/executive control system