Limbic System Lecture

Question 1

Limbic Structures

Answer 1

1) highly interconnected structures in medial part of the telencephalon
- lie between neocortical association areas and hypothalamus
2) major route for info transfer b/w neocx and hypothalamus

Question 2

Functions of limbic system

Answer 2

Emotion and memory

Question 3

Olfactory Bulb Diagram

Answer 3

1) processed in several regions of cerebral cx
2) Olfactory sensory neuron (CN1)
- extends through cribriform plate and olfactory epithelium
- receives sensory
3) Info is transmitted from the olfactory bulb by:
- Mitral relay neurons
- Tufted relay neurons
- travel in lateral olfactory tract
4) Mitral cells project to 5 different regions of olfactory cortex
- anterior olfactory. nucleus->contralateral olfactory bulb via Medial Olfactory Stria and Anterior Commissure
- olfactory tubercle
- piriform cortex
- Amygdala
- entorhinal cortex
5) Tuft cells
- > anterior olfactory nucleus (primarily)-> contralateral olfactory bulb via medial olfactory stria and anterior commissure
- olfactory tubercle
6) Pheromone pathway
- Vomeronasal organ (not conscious)-> Accessory olfactory bulb
- where mitral cells-> only amygdala

Question 4

Olfactory-sense of smell

Answer 4

1)all sensory communicates with thalamus
EXCEPT Olfactory
-communicates w/gray matter then go to thalamus
2) strong communication to memory and emotion
3) Strongest memories are with smell

Question 5

Pheromone pathway

Answer 5

1) Big sexual driver in animals NOT humans
- not a conscious smell
- no learned
2) Vomeronasal organ-> Accessory olfactory bulb
- contain mitral cells that only project to amygdala (sexual desire)

Question 6

Entorhinal Cortex

Answer 6

1) Major input to hippocampus

- declarative memory

Question 7

Septal Area

Answer 7

Pleasure Center

Question 8

NTs involved with pleasure and addiction

Answer 8

1) Dopamine
2) endorphines
3) Enkephlins
4) Serotonin
5) GABA
2&3=opoids

Question 9

Nuclei for Addiction and Pleasure

Answer 9

1) Basal Nucleus of Meynert (BNM)
aka substantia innominata 
2) Nucleus acumen
3) Septal Nuclei
4) Ventral Tegmentum Area
2,3,4=addiction

Question 10

Basal Nucleus of Meynert

Answer 10

1) AKA substantia innominata
2) Part of limbic system
- influences emotion, motivation, and memory
3) Sends Ach efferents through the cortex
4) Degenerates w/Alzheimers
- basis for memory loss

Question 11

Nucleus Accumbens

Answer 11

1) major role in addiction
2) Dopamine receptors
3) Drugs like cocaine enhance dopamine activity in this nucleus

Question 12

Septal Nuclei

Answer 12

1) Major role in addiction
2) pleasure center
3) When stimulated=euphoric feeling->orgasm

Question 13

Ventral Tegmentum Area (VTA)

Answer 13

1) Located in midbrain
2) Strong projections to:
- Nucleus Accumbens
- Limbic system
- prefrontal cortex (judgement and behavior)
- insular cortex (behavior)
3) Addiction

Question 14

Fimbria of hippocampus

Answer 14

1) efferent fibers to maxillary bodies

Question 15

Major Afferents to hippocampus

Answer 15

1) Cingulate GYRUS
2) Entorhinal cortex (MAJOR)
3) AMygdala
4) Hypothalamus via fornix
5) Septal area-via fornix

Question 16

Major Efferents from hippocampus

Answer 16

1) Frontal Cortex
2) Nucleus accumbens
3) Septal Nucleus
4) Mammilary Bodies
5) Thalamus
6) Amygdala
7) Hypothalamus
8) Entorhinal cortex

Question 17

Uncinate Fasciculus

Answer 17

Tract from frontal cx to temporal lobe
-only has minor input to hippocampus
(minor afferent)

Question 18

L Cingulate Gyrus

• function
• anterior lesion

Answer 18

1) Maternal instinct
2) Lesion
- right sided emotion facial paralysis for involuntary movement
- voluntary movement not affected

Facial expression doesn’t match emotion