Limbic System

Question 1

what is the main function of the limbic system?

Answer 1

the assignment of value

**pretty much connected to everything
motivation, fear, anger, emotions, learning, memory,

Question 2

what structures are associated with the limbic system?

Answer 2

amygdala
hippocampus
septal region

Question 3

what are the 3 things that form the hippocampus?

what is the papez circuit?

Answer 3

1-dentate gyrus
2-hippocampus proper (archicortex)
3-subiculum

papez circuit -limbic system
(cingulate gyrus- hippocampus- fornix- hypothalamus (mammillary bodies)- thalamus- cortex

Question 4

what is the function of the hippocampus?

Answer 4

formation of new memories and learning

-important in converting short term memories to long term

Question 5

what would be the result of damage to the hippocampus? what is the specific name for this?

Answer 5

profound loss of recent or short-term memory and the ability to learn= anterograde amnesia

older memories from before injury are unharmed

intact hippocampus allows the animal to compare the conditions of a present threat with similar part experiences- thus enabling it to choose the best option, in order to guarantee its own survival

Question 6

what is the location of the amygdaloid nucleus?

Answer 6

deep to the uncus

Question 7

what is the function of the amygdaloid? what is its major afferent?

Answer 7

major afferent= smell

functions:

• important in behavior and emotions
• programs appropriate behavioral responses (anger, fear, sexual responses)

Question 8

what are the results of a lesion to the amygdaloid?

Answer 8

bilateral lesion results in profound behavioral alterations

loose affective meaning of the perception of outside info, like the sight of a well known person. the subject knows exactly who the person is, but it not capable to decide whether he likes or dislikes them

Question 9

what are the 3 nuclear divisions of the amygdala?

Answer 9

1- central nuclei
2-cortical nuclei
3- basolateral nuclei

Question 10

describe the basolateral nuclei:

what does it do?
where does it project?

Answer 10

thalamus, sensory cortex–> basolateral nucleus

projects to:

• frontal lobe
• thalamus
• temporal lobe

functions:

• though to attach emotional significance to a stimulus
• links stimuli with particular emotions (hearing a sound)

Question 11

what do central nuclei do?

Answer 11

mediates emotional response

regulates autonomic NS

helps shape responses to emotional stimuli

Question 12

what do the cortical nuclei do?

Answer 12

olfactory perception

role in behaviors triggered by smell

Question 13

where does the septal region send fibers to?

what is its function?

Answer 13

sends fibers to BS RF

• when the septal region is stimulated in conscious patients there are feelings of pleasure, optimism, euphoria, happiness
• involved with reward or pleasure (connection with hypothalamus)
• centers of orgasm

area of pleasure- dopamine goes here

nucleus accumbens of BG goes here

Question 14

what is the cingulate gyrus? what does it do?

Answer 14

part of the cerebrum that lies closest to the limbic system, just above the corpus collosum

provides a pathway from the thalamus to the hippocampus

seems to be responsible for focusing attention on emotionally significant events and for associating memories to smells and to pain

Question 15

what is the anterior cingulate cortex? how is it divided? what does it do?

Answer 15

can be divided anatomically- attributed to functions into:

• executive (anterior)
• evaluative (posterior)
• cognitive (dorsal)
• emotional (ventral)

ACC seems to be especially involve when effort is needed to carry out a task such as in early learning and problem solving

many studies attribute functions such as:

• error detection
• anticipation of tasks
• motivation
• modulation of emotional responses to the ACC

Question 16

what is the ventral tegmental area?

people with damage here tend to??

Answer 16

area of the BS (just below the thalamus)

consists of dopamine pathways that seem to be responsible for pleasure

people with damage here tend to have difficulty getting pleasure in life– often turn to alcohol, drugs, sweets and gambling

Question 17

what is the basal ganglia?

Answer 17

responsible for repetitive behaviors, reward experiences, focusing attention

Question 18

what is the prefrontal cortex?

Answer 18

part of the frontal lobe which lies in front of the motor area

closely linked to the limbic system

besides apparently being involved in thinking about the future, making plans, and taking action, it also appears to be involved in the same dopamine pathways at the ventral tegmental area and plays a part in pleasure and addiction

Question 19

what is Kluver-Bucy syndrome?

Answer 19

=bilateral removal of the temporal lobes

absence of emotional response so that fear, rage and aggression cease to exist (amygdaloid)

a compulsion to be overly attentive to all sensory stim (exam on object with all sensory modalities)

hypersexual

psychic blindness or visual agnosia (neocortical pathway to temporal lobe)= inability to recognize the meotional importance of events

Question 20

what are Korsakoff Syndromes?

Answer 20

=loss of recent memory and a tendency to fabricate false accounts of recent events

hippocampus, maxillary bodies and esp medial dorsal thalamic nucleus

Alzeimer’s disease

Question 21

what is alzeimer’s disease?

Answer 21

progressive dementia in patients under 65

associated with a loss of neurons in the hippocampal formation