Olfactory and limbic systems

Question 1

What is the limbic system?

Answer 1

Acts as an interface between the internal environment of the individual and the external environment - projects meaning onto the external world. Essential for adaptive behaviour, emotional responsiveness and the ability to learn new responses based on previous experiences (memory). Intimately related to the olfactory system.

Question 2

Two main functional roles have been assigned to the limbic system - what are they?

Answer 2

1. role in learning
2. role in the regulation and translation of our emotional state into appropriate behaviour

Question 3

Quick way to remember the functions of the limbic system is to think about the 5 F’s - what are they?

Answer 3

1. feeding (satiety & hunger)
2. forgetting (memory)
3. fighting (emotional response)
4. family (sexual reproduction and maternal instincts)
5. fornicating (sexual arousal)

Question 4

What is the parahippocampal gyrus?

Answer 4

is in continuity with the cingulate gyrus around the splenium of the corpus callosum - part of the temporal lobe

Question 5

What are the constituents the comprise the basal ganglia?

Answer 5

basal ganglia consist of the caudate nucleus, putamen, globus pallidus and amygdala

Question 6

What term do we use for the white matter that connects the cortex of the cerebral hemisphere to other structures?

Answer 6

internal capsule

Question 7

Another way to remember what the limbic system does is with HOME - what does this stand for?

Answer 7

Homeostasis
Olfaction
Memory
Emotion

Question 8

What structures are involved in the limbic system?

Answer 8

hypothalamus, olfactory cortex, hippocampal formation, amygdala, subcallosal area, cingulate gyrus, parahippocampal gyrus, mamillary bodies and the basal forebrain

Question 9

What is the hippocampal formation involved in?

Answer 9

crucial for converting short term memories into long term memories. Also involved in spatial orientation - enables us to identify the position of our body relative to the objects around us

Question 10

What does the hippocampal formation consist of?

Answer 10

hippocampus, dentate gyrus, subiculum and entorhinal cortex
note - subiculum is the most inferior part of the hippocampal formation and is continuous with the parahippocampal gyrus

Question 11

What is the function of the hippocampus?

Answer 11

hippocampus is involved in long term memory and helps us decide what should be stored within the cerebral cortex as a memory

Question 12

What structures does the hippocampus have connections with?

Answer 12

olfactory cortex - hence why smells elicit memories
amygdala - remember emotionally significant events

Question 13

Which 3 structures are in the temporal lobe?

Answer 13

amygdala
hippocampus
inferior horn of the lateral ventricle

Question 14

principal components of the limbic lobe are connected via which circuit?

Answer 14

papez circuit

Question 15

What structures make up the corpus striatum?

Answer 15

caudate nuclei, globus pallidus and putamen

Question 16

What is the function of the caudate nucleus?

Answer 16

caudate nucleus functions not only in planning the execution of movement, but also in learning, memory, reward, motivation, emotion, and romantic interaction

Question 17

What makes up the basal ganglia?

Answer 17

caudate nucleus, putamen, globus pallidus, subthalamic nucleus, and substantia nigra.

Question 18

What makes up the neostriatum?

Answer 18

putamen and caudate nucleus

Question 19

Which are the input nuclei of the basal ganglia?

Answer 19

neostriatum = caudate nucleus and putamen

Question 20

Which are the intrinsic nuclei of the basal ganglia?

Answer 20

external globus pallidus
subthalamic nucleus
pars compacta of the substantia nigra

Question 21

Which are the output nuclei of the basal ganglia?

Answer 21

internal globus pallidus
pars reticulata of the substantia nigra

Question 22

What makes up the lentiform nucleus?

Answer 22

globus pallidus and putamen

Question 23

The arterial supply to the basal ganglia mainly comes from where?

Answer 23

the middle cerebral artery - continuation of the internal carotid artery
but the SN and subthalamic nucleus are more posterior and thus receive its vasculature from branches of the posterior cerebral and posterior communicating arteries