Lesson 10 -Neural Circuits of the Limbic System

Question 1

limbic system function

Answer 1

Emotional and behavioural expression

Question 2

function of the limbic system: 5 F’s

Answer 2

*Feeding (satiety & hunger)
*Forgetting (memory)
*Fighting (emotional response)
*Family (reproduction, maternal behavior)
*Fornicating (sexual arousal)

Question 3

limbic system etymology:

Answer 3

: Limbic from Latin limbus = edge or border (near cortex edge)

Question 4

Components of the Limbic System include:

Answer 4

(1) cortical components (limbic love)
(2) subcortical components

Question 5

Cortical Components (Limbic Lobe) of the limbic system (5) :

Answer 5

Orbitofrontal Cortex
Insular Cortex
Cingulate Gyrus Parahippocampal Gyrus
Hippocampus

Question 6

Orbitofrontal Cortex:

Answer 6

Smell perception; memory formation

Question 7

• Hippocampus:

Answer 7

Long-term memory

Question 8

insular cortex:

Answer 8

desires, cravings, addiction

Question 9

cingulate gyrus:

Answer 9

Pain perception (neuropathic, nociception)

Question 10

Parahippocampal Gyrus

Answer 10

Connects cortical areas to hippocampus

Question 11

Subcortical Components (5):HOTAS

Answer 11

amygdala
olfactory bulb
hypothalamus
thalamus
septal nuclei

Question 12

amygdala function

Answer 12

fear, anxiety
in subcortical component

Question 13

olfactory bulb

Answer 13

smell detection
subcortical component

Question 14

Hypothalamus

Answer 14

Limbic system output (autonomic and endocrine control)
Subcortical Components

Question 15

Thalamus

Answer 15

Relay between limbic and cortex

Question 16

• Septal Nuclei

Answer 16

Reward and motivation

Question 17

Limbic Structures Classified as Core vs. Extended
A. Core

Answer 17

• Hippocampus, Amygdala, Hypothalamus
• Cingulate Gyrus
• Fornix
• Entorhinal & Parahippocampal Cortices

Question 18

Limbic Structures Classified as Core vs. Extended:B. Extended

Answer 18

• Septal Nuclei
• Nucleus Accumbens
• Orbitofrontal
• Insular Cortices
• Anterior & Mediodorsal Thalamus

Question 19

Subiculum:

Answer 19

Transition area between hippocampus and entorhinal cortex

Question 20

The Hippocampus structure

Answer 20

Hippocampus proper (CA1-CA3), dentate gyrus (DG)

Question 21

Hippocampus Location:

Answer 21

Medial temporal lobe, forms floor of temporal horn of lateral ventricle

Question 22

Hippocampus output:

Answer 22

fibers of the alveus → fimbria → fornix

Question 23

Intra-Hippocampal Circuitry:* Classical Perforant Pathway

Answer 23

EC Layer II → DG → CA3 → CA1

Question 24

• Direct Perforant Pathway

Answer 24

EC Layer III → CA1 and subiculum

Question 25

* Alvear Pathway:

Answer 25

EC Layer III → CA1 (travels through alveus, bypassing DG & CA3)

Question 26

. Intra-Hippocampal Circuitry

Answer 26

Classical Perforant Pathway Direct Perforant Pathway Alvear Pathway CA1

Question 27

CA1:

Answer 27

Major output region to entorhinal cortex (layer V)

Question 28

Papez Circuit (Extra-Hippocampal): pathway

Answer 28

Hippocampus → Fornix → Mammillary bodies of the hypothalamus → Mammillothalamic tract → Anterior thalamic nuclei → Cingulate gyrus (communicates with cortex) → Parahippocampal gyrus → Hippocampus

Question 29

Papez Circuit (Extra-Hippocampal: function

Answer 29

Episodic memory integration

Question 30

amygdala function:

Answer 30

Integrates emotion, behavior, motivation

Question 31

amygdala inputs:

Answer 31

o All sensory modalities o Visceral input (e.g., hypothalamus, septal area, orbitofrontal cortex

Question 32

amygdala output(3):

Answer 32

o Ventral Amygdalofugal Pathway o Stria Terminalis o Direct projections to and from: Hippocampus, entorhinal, thalamus (dorsomedial nucleus), brainstem

Question 33

amygdala important for:

Answer 33

Associative learning (associating neutral stimuli to reward/punishment).

Question 34

for faster reactions to potentially dangerous stimuli.

Answer 34

: sensory input can fast track from thalamus/midbrain colliculi to amygdala without passing via cortex,

Question 35

The Hypothalamus function

Answer 35

Maintains homeostasis (temp, thirst, stress, circadian rhythms)

Question 36

The Hypothalamus:* Four Areas comprising various nuclei (abbreviated as n.):

Answer 36

o Preoptic (e.g., suprachiasmatic n.) o Supraoptic (e.g., paraventricular n., supraoptic n., anterior n.) o Tuberal (e.g., ventromedial n., dorsomedial n., infundibular/arcuate n.) o Mammillary (e.g., posterior n., mammillary bodies)

Question 37

o Supraoptic nuclei

Answer 37

paraventricular n., supraoptic n., anterior n.

Question 38

tuberal nuclei composed of 3

Answer 38

ventromedial n., dorsomedial n., infundibular/arcuate n

Question 39

mammillary nuclei composed of

Answer 39

posterior n., mammillary bodies

Question 40

hypo inputs: ascending

Answer 40

: from spinal cord (spinohypothalamic pain fibers) & brainstem (midbrain tegmental nuclei, Periaqueductal gray, catecholamine pathways

Question 41

input hypothalamus: descending

Answer 41

limbic system (hippocampus, amygdala, septal nuclei, dorsomedial and midline n. of thalamus, orbitofrontal cortex, piriform cortex), retina, vascular system (hormones, temperature, osmolality)

Question 42

The Circuit of Circadian Control:

Answer 42

* suprachiasmatic n. → hypothalamic paraventricular n. → intermediolateral n. of the spinal cord → superior cervical ganglion → Pineal gland → Release of Melatonin

Question 43

* Feedback to SCN regulates

Answer 43

rhythm

Question 44

Rodent vs. Human Limbic Structures : olfactory more prominent in:

Answer 44

rodents

Question 45

Rodent vs. Human Limbic Structures: both specoes have conservedÈ

Answer 45

hippocampal, amygdala and hypothalamic pathways

Question 46

Functional Themes: Reciprocal communication is common especially in

Answer 46

amygdala, hippocampus

Question 47

neural circuits of the limbic system integrate:

Answer 47

sensory, visceral, and contextual information for behavior

Question 48

* Limbic outputs influence

Answer 48

learning, memory, emotion, endocrine responses, and motivation

Question 49

3. Which of the following pathways bypasses the dentate gyrus and CA3

Answer 49

Alvear pathway

Question 50

4. The Papez circuit is primarily involved in:

Answer 50

Declarative memory

Question 51

5. Which pathway connects the hippocampus to the mammillary bodies

Answer 51

Fornix

Question 52

6. Which pathway connects the mammillary bodies to the thalamus

Answer 52

Mammillothalamic tract

Question 53

7. What hypothalamic nucleus is involved in circadian rhythm regulation?

Answer 53

) Suprachiasmatic nucleus