Limbic System

Question 1

the four functions of the limbic system

Answer 1

HOME: homeostasis, olfactory processing, memory processing, emotional content of memories

Question 2

the cingulate gyrus above the corpus collosum, the parahippocampal gyrus on the medial aspect of the temporal lobes, and the orbitofrontal gyri above the orbits are related in that they are all a part of the….

Answer 2

limbic lobe

Question 3

buried deep inside the parahippocampal gyri on the medial aspect of each temporal lobe are an array of structures associated with the ___

Answer 3

hippocampus

Question 4

the most medial part of the temporal lobe is known as the

Answer 4

uncus

Question 5

underneath the uncus (the most medial part of the temporal lobe) is the ____, which lies anterior to the hippocampal formation

Answer 5

amygdala

Question 6

the subcortical structures on the medial aspect of each hemisphere but on the most inferior parts of each frontal lobe are the ____ nuclei

Answer 6

septal nuclei, involved in emotional response and reward

Question 7

the olfactory mucosa contain what type of neurons?

Answer 7

bipolar neurons, which give rise to olfactory receptors embedded in mucosal lining of nasal cavity, and also to central processes that pass through the cribriform plate

Question 8

the bipolar neurons pass through this sieve-like bone found between the superior aspect of the nasal cavity and the anterior cranial fossa. what is the?

Answer 8

cribriform plate

Question 9

T/F: the olfactory nerve (CN I) is not a single nerve

Answer 9

TRUE: simply a bunch of bipolar neurons that send their central processes through the cribriform plate to synapse on 2nd neuron in overlying olfactory bulb (containing mitral cells)

Question 10

cribriform plate fracture results in this symptom

Answer 10

CSF rhinorrhea

Question 11

the ___ cells in the olfactory bulb send their axons through the olfactory tract to the primary olfactory cortex

Answer 11

mitral cells

Question 12

the olfactory bulb (mitral cells) and tract axons project to the ____ in the olfactory cortex, the ____ in the medial temporal lobe, and the ____ in the hippocampal formation in the parahippocampal gyrus

Answer 12

the olfactory bulb (mitral cells) and tract axons project to the PIRIFORM CORTEX in the olfactory cortex, the AMYGDALA in the medial temporal lobe, and the ENTORHINAL CORTEX in the hippocampal formation in the parahippocampal gyrus

Question 13

the only sensory system that reaches cortical area without relaying through the thalamus

Answer 13

olfactory system

Question 14

what are the neurons in the olfactory pathway?

Answer 14

1. bipolar neurons in nasal mucosa
2. mitral cells in olfactory bulb
3. piriform cortex in olfactory cortex, amygdala, entorhinal cortex in hippocampal formation

Question 15

major location for developing emotional content memories

Answer 15

amygdala

Question 16

what are the three components of the hippocampus, forming the shape of a seahorse?

Answer 16

hippocampus proper (Ammon’s horn)
dentate gyrus
subiculum

Question 17

lying adjacent to the hippocampus (proper, dentate gyrus, and subiculum) is the ____ cortex of the parahippocampal gyrus

Answer 17

entorhinal cortex

Question 18

the ____ cortex in the parahippocampal gyrus provides virtually all daily input that is arriving and being processed by hippocampus

Answer 18

entorhinal cortex

Question 19

besides the entorhinal cortex (parahippocampal gyrus), the hippocampus proper also receives some input from these two places:

Answer 19

septal nuclei (medial and most inferior of temporal lobe)
amygdala

Question 20

these nuclei are a major location in the brain of cholinergic neurons that project their axons via the fornix into the hippocampal formation, and they play a role in enhancing memory consolidation. what are?

Answer 20

septal nuclei (including within the basal nucleus of Meynert)

Question 21

the axons leaving the entorhinal cortex headed to the hippocampus proper exit via the ____

Answer 21

perforant path (perforates the hippocampal formation)
these synapse with granule cells in dentate gyrus of hippocampus

Question 22

the axons of the entorhinal cortex exit via the perforant path and synapse on the ___ in the ___

Answer 22

granule cells in the dentate gyrus. granule cells then project to cornu ammonis region 3 (CA3) pyramidal cells in hippocampal formation

Question 23

after receiving input from entorhinal cortex, the granule cells of the dentate gyrus (hippocampus) synapse on the cornu ammonis region 3 (CA3) pyramidal cells in the hippocampal formation, which then synapse on ____ (also in hippocampal formation)

Answer 23

pyramidal cells

Question 24

where are the 3 levels that long-term potentiation occurs in the hippocampus?

Answer 24

1. granule cells (receiving input from entorhinal cortex)
2. CA3 pyramidal cells
3. CA1 pyramidal cells

Question 25

the outflow of newly-consolidated memories within the hippocampus project to the ____

Answer 25

subiculum- major destination of hippocampal formation outflow

Question 26

major destination of hippocampal formation outflow

Answer 26

subiculum (Latin for "support")

Question 27

the axons that leave the subiculum (major destination of hippocampal formation outflow) do what?

Answer 27

coalesce on the surface to form the alveus (located on the lateral ventricle surface of the hippocampal formation) alveus axons then coalesce to form fimbria, and ultimately fornix

Question 28

major efferent pathway of the hippocampal formation?

Answer 28

fornix

Question 29

what are the neurons of the Papez circuit?

Answer 29

1. memories consolidated in hippocampal formation (granule cells, CA3, CA1), input from entorhinal cortex 2. axon outflow via fornix (subiculum) 3. post-commissural fornix axons project to mammillary body (diencephalon) [pre-commissural fornix project to septal nuclei and nucleus accumbens, but not main projection] 4. mammillary body projects to anterior nucleus (thalamus) 5. cingulate gyrus (limbic associated cortex), which closes circuit by projecting back to entorhinal cortex (parahippocampal gyrus)

Question 30

the pre-commissural axonal projections of the fornix project where?

Answer 30

septal nuclei and nucleus accumbens | post-commissural fornix is major output, going to mammillary body

Question 31

on the medial aspect of the frontal and parietal lobes above the corpus collosum is the end destination of the Papez circuit. what is the?

Answer 31

cingulate gyrus

Question 32

a chronic abuser of alcohol or someone deficient in thiamine (Vit B1) develops selective degeneration of what set of neurons? what is this condition called?

Answer 32

mammillary body in hypothalamus (diencephalon) | --> Korsakoff psychosis

Question 33

irreversible degenerative loss of mammillary neurons bilaterally

Answer 33

Korsakoff psychosis | alcoholism or vitamin B1 (thiamine) deficiency

Question 34

a person who develops Korsakoff syndrome may develop long-term gait problems (gait ataxia) due to neural changes in what area?

Answer 34

anterior vermis of cerebellum

Question 35

where does Alzheimer's dementia develop initially?

Answer 35

``` entorhinal cortex (subiculum of hippocampus) neurofibrillary tangles and senile plaques here ```

Question 36

over time, a patient with Alzheimer's may develop what kind of preferential aphasia?

Answer 36

Wernicke's (fluent) aphasia

Question 37

what are the two regions of the amygdala? what inputs do they receive?

Answer 37

basolateral region- external stimuli | corticomedial region- visceral input

Question 38

Kluver-Bucy syndrome

Answer 38

bilateral lesion of amygdala, usually includes nearby hippocampus--> profound amnesia (anterograde and retrograde) placid or docile- lacking appropriate emotional responses (esp. fear) oral tendencies (putting things in mouth), hypersexuality possible visual agnosia

Question 39

a patient presents with anterograde and retrograde amnesia, a placid disposition, hypersexual comments, and prosopagnosia (inability to recognize familiar faces). where is the lesion?

Answer 39

bilateral lesion of amygdala, and lesion of nearby hippocampus Kluver-Bucy syndrome

Question 40

near the septal nuclei of the anterior basal part of the forebrain, right near the juncture between the putamen and the caudate nucleus, just underneath the anterior limb of the internal capsule is the....

Answer 40

nucleus accumbens

Question 41

what are the 3 sources of input to the mesolimbic projection in the basal ganglia as part of the reward circuit?

Answer 41

amygdala, hippocampus, prefrontal cortex