NeuroAnatomy - Lecture 13 - Limbic System

Question 1

What is the limbic system’s function?

Answer 1

controls the functions that are necessary for self-preservation and species survival

Question 2

What are some of the roles the limbic system controls?

Answer 2

sleep/wake cycle, feeding/appetite, sexual reproduction/nurturing, fight/flight, motivation/addiction

Question 3

What cortical structures make up the limbic system?

Answer 3

cingulate gyrus, parahippocampal gyrus, amygdala

Question 4

What subcortical structures make up the limbic system?

Answer 4

hypothalamus, mammillary bodies, septal nuclei, anterior thalamic nuclei, fornix, stria terminalis, olfactory tract

Question 5

What is the function of the septal nuclei?

Answer 5

located in prefrontal cortex, associated with pleasure and reproduction

Question 6

What is the function of the fornix?

Answer 6

connects the mammillary bodies to the hippocampus

Question 7

What is the function of the stria terminales?

Answer 7

connects the amygdala to the hypothalamus

Question 8

What is the function of the cingulate gyrus?

Answer 8

processes emotions and sensations with actions // modifies behavior and communicates with motor, endocrine, and autonomic systems

Question 9

What is the function of the parahippocampal gyrus?

Answer 9

acts as a staging area for memory formation

sensory information enters the parahippocampal gyrus and is sent to hippocampus to be developed into long term memory

Question 10

What is the function of the hippocampus?

Answer 10

central role in memory formation // sensory information is sent to entorhinal cortex of parahippocampal gyrus to be stored

Question 11

What happens if there is a bilateral lesion/damage to the hippocampus?

Answer 11

patient is unable to form new long-term memories, but previous long-term memories can still be retrieved due to being stored in other areas of cortex

Question 12

What is the function of the hypothalamus?

Answer 12

maintains homeostasis, regulates endocrine/autonomic/behavioral/sexual functions

Question 13

Where is the amygdala located?

Answer 13

deep within the uncus

Question 14

What is the function of the amygdala?

Answer 14

generates behavioral responses to sensory stimuli (fear, anger, rage, anxiety) // provide instinctive behavorial responses relating to human survival

Question 15

What is the short loop pathway of the amygdala?

Answer 15

thalamus sends sensory input to amygdala –> amygdala processes info and generates emotional survival response –> stored as implicit memory

Question 16

What is the long loop pathway of the amygdala?

Answer 16

thalamus sends sensory input to cortex –> uses explicit memory to decide how to act in response to stimuli –> cortex/hippocampus shares memory with amygdala –> amygdala compares it’s implicit memory to learned explicit memory to generate a modified emotional response

Question 17

What is the difference between implicit and explicit reponses?

Answer 17

implicit = fast/quick response, instinctive or reaction, short loop // explicit = slower response, response was thought out, long loop

Question 18

What is an amygdala hijack?

Answer 18

an abrupt inappropriate emotional response followed by post-response realization of the response was inappropriate

Question 19

What occurs when there is a lesion to the amygdala?

Answer 19

reduced emotional responses to stimuli

Question 20

What is Kluver-Bucy Syndrome?

Answer 20

rare bilateral lesion to amygdala resulting in tame, non-aggressive behavior

Question 21

What occurs when there are Irritative lesions (seizures) of the amygdala?

Answer 21

strong emotions of fear/panic, loss of control, hyperactivity

Question 22

The amygdala is involved in the fear, anger, anxiety responses… but what else is it involved in?

Answer 22

pleasure and reward pathways // part of the dopaminergic pathways

Question 23

What is the memory pathway “hierarchy?”

Answer 23

sensory memory (fleeting memory) –> attention –> short term memory –> long term memory

Question 24

How long does sensory memory last?

Answer 24

a few seconds, anywhere from 0.3 - 10 seconds

Question 25

What role does attention play in memory?

Answer 25

to form short or long term memories, cortex needs to direct attention to stimulus and allow info to enter short term memory pathways

Question 26

How long does short term memory last?

Answer 26

information is temporarily stored in cortex, can be recalled within a minute. Possibly lasts anywhere from 15-60 seconds

Question 27

How long does long term memory last?

Answer 27

encoded in medial temporal lobe, stored in cortex for recall that lasts anywhere from minutes to years

Question 28

What are the components of STM?

Answer 28

attention, working memory, immediate recall

Question 29

What are the components of LTM?

Answer 29

encoding, storage, retrieval

Question 30

Which regions of the brain are involved in STM?

Answer 30

brainstem, thalamus, hypothalamus, cortex/anterior associative area

Question 31

What are the two types of LTM?

Answer 31

Implicit (Non-Declarative) Memory & Explicit (Declarative) Memory

Question 32

What are the concepts of Implicit Long Term Memory

Answer 32

things you know that you can show by doing, physical skills

Question 33

What are the concepts of Explicit Long Term Memory?

Answer 33

conscious recall of info that you can tell others // semantic and episodic

Question 34

What is Semantic Memory?

Answer 34

recall of factual knowledge of historical events/people, recognize people, academic information

Question 35

What is Episodic Memory?

Answer 35

experiential recall of events in someone’s life

Question 36

What is Amnesia?

Answer 36

loss of declarative memory

Question 37

How do unilateral lesions in declarative memory present?

Answer 37

unilateral lesion rarely causes severe declarative memory loss, in dominant hemisphere may produce verbal memory loss and in non-dominant may produce visual-spatial loss

Question 38

How do bilateral lesions in declarative memory present?

Answer 38

results in more severe declarative memory loss

Question 39

What is Anterograde Amnesia?

Answer 39

loss of ability to memorize new things after an injury

Question 40

What is Retrograde Amnesia?

Answer 40

can’t recall events prior to injury

Question 41

What is Repressed Amnesia?

Answer 41

unable to recall information often due to trauma

Question 42

What is Dissociative Amnesia?

Answer 42

fugue state // psychological trauma and is usually temporary