Limbic System HY

Question 1

papez circuit original proposed pathway

Answer 1

hippocampal fibers –> mammillary bodies –> anterior nucleus –> cingulate gyrus –> hippocampal formation

Question 2

Kluver-Bucy syndrome

Answer 2

• behavioral syndrome
• due to bilateral removal of medial temporal lobes in monkeys
• fearless/placid
• hypersexuality
• excessive sniffing/oral examination

SHOWED IMPORTANCE OF INTACT LIMBIC STRUCTURES AND CONNECTIONS TO APPROPRIATE BEHAVIORAL PATTERNS
(note: amygdala was also taken)

Question 3

Papez circuit - updated structures

Answer 3

addition of:

• prefrontal cortex
• association cortex
• amydala
• DMN thalamus
• hypothalamus

hippocampal fibers –> mammillary bodies –> anterior nucleus –> cingulate gyrus –> hippocampal formation

Question 4

function of orbital and medial prefrontal cortex

Answer 4

planning and choosing appropriate responses to life situations

Question 5

septal nuclei

Answer 5

• pleasure center
• cholinergic input to hippocampus

lesion = rage

Question 6

hippocampus has been implicated in:

Answer 6

• memory function
• Alzheimer’s disease
• schizophrenia
• hippocampal sclerosis and epilepsy
• autism
• depression
• modulating endocrine functions (via input to hypothalamus)
• modulation of aggressive behaviors

Question 7

role of hipppocampus in emotion

Answer 7

• INDIRECT role in emotion

- via connections to limbic cortex, amygdala, septal nuclei, and regulation of stress axis

Question 8

hippocampus is essential for _________

Answer 8

hippocampus is essential for FACTUAL/DECLARATIVE MEMORY

Question 9

which part of the limbic system contains stem cells?

Answer 9

DENTATE gyrus

• part of hippocampal formation
• everyone (except Alz pts) have v prolific stem cells

Question 10

HM research patient

Answer 10

• seizures
• experimental surgery to take out medial temporal structures, hippocampus (and surrounding cortex) bilaterally

After

• few seizures
• unable to form new long-term memories
• profound retrograde amnesia

Question 11

functional elements of declarative memory

Answer 11

experience –> short term memory –> consolidation process –> long term storage

• consolidation process requires hippocampal formation
• formation of long term memory requires sleep

Question 12

amygdala is implicated in:

Answer 12

• temporal lobe epilepsy
• schizophrenia
• Alzheimer’s
• autism
• anxiety states/PTSD
• affective disorders
• panic disorders
• emotional memory

Question 13

functions of amygdala

Answer 13

• determining affective perception of sensory stimuli
• attaches emotional significance to various stimuli perceived by association cortex
• plays central role in fear and fear conditioning

Question 14

“low road” to amygdala

Answer 14

emotional stimulus –> sensory thalamus –> amygdala –> emotional responses

• reflexive
• keeps us alive in dangerous situations
• problematic in police force

Question 15

“high road” to amygdala

Answer 15

emotional stimulus –> sensory thalamus –> SENSORY CORTEX –> amygdala –> emotional responses

-normal route

Question 16

effect of chronic stress on amygdala

Answer 16

• no feedback to stop stress response

- cannot protect from damage

Question 17

missing amygdala

Answer 17

SM

• has no fear
• cannot recognize fear
• cannot draw fear

Question 18

role of amygdala in memory

Answer 18

EMOTIONAL MEMORY
Amnesic patient:
-Dr shook hands w/ thumbtack
-pt never shook hand w/ Dr again
-did not recognize Dr

David (pt)

• could not recognize anyone
• drawn to those who were nice to him

Question 19

implicit vs explicit emotional memory

Answer 19

IMPLICIT

• amygdala
• emotional response (panic, fear)

EXPLICIT

• hippocampus
• facts, details

Question 20

role of noradrenaline

Answer 20

• released during stress

- thought to stabilize/strengthen memories

Question 21

effect of stress on memory

Answer 21

• mild stress enhances memory

- chronic stress interferes w/ memory (via hippocampus)