UNIT 9 - LIMBIC SYSTEM

Question 1

LIMPIC SYSTEM IS:

Answer 1

Not a structure but rather a phylogenetically* (Regarding evolution)

1. Motivation and emotion
2. Learning and memory

Question 2

Raphe Nucleus

Answer 2

Control temperature in the body (Hypothalamus)

Question 3

Hypothalamus + autonomic nervous system regulate?

Answer 3

Physiological changes associated with emotional response

It is in contract with the limbic system that is responsible for the perception and feeling of emotion

Question 4

Limpic system - PAPEZ CIRCUIT (1937)

Answer 4

First neuroscientific theory: a neural circuit responsible for the expression of emotion

Question 5

PAPEZ CIRCUIT HOW IT SENDS (oversimplification)

Answer 5

1. We start with the hippocampus,
2. then fibers travel via the fornix to the mammillary body via mammal oath Olympic
3. tract to the anterior nucleus of the thalamus,
4. then to the cingulate gyrus in the cingulum the internal cortex
   And finally back to the hippocampus

The late additional region was added to this circuit, now called LIMPIC SYSTEM.

Question 6

Limpic system consist of:

Answer 6

Consist of: 
Limbic cortex, 
Amygdala, 
Hippocampus, 
Mamillary bodies of the hypothalamus and the Septum. 

Important connections: 
Hypothalamus
Anterior Nucleus of the thalamus 
Orbitofrontal cortex 
Olfactory bulb

Question 7

Surrounding of lympic system:

Answer 7

Cingulate cortex

Medial Temporal lobe

Question 8

Amygdala (anterior to hippocampus)

Answer 8

Plays a role in emotional processing
responsible: for giving emotional significance to these stimuli and coordinating the emotional response (fear aggression)

Question 9

Amygdala - Role in emotion

• Behavioural
• Autonomic
• Hormonal

Answer 9

Behavioral Response: fight or flee

Autonomic response: facilitates behavioral response (SYPMA increase - PARA decrease

Hormonal response: release of adrenalin and noradrenalin > medulla

Question 10

Amygdala Nuclei

Question 11

Central Nuclei - 12

• Lateral nuclei
• Basal nuclei
• Central nuclei

Answer 11

Lateral nuclei: it is via these routes that sensory information about the external world reaches the amygdala
> Lateral sends a signal to the BASAL nucleus of the amygdala & DM = Process emotion and mood

Central nuclei: main output channel of amygdala: important brain structure for the expression of emotional response

Question 12

Central nucleus of Amygdala

Answer 12

Is important in the expression of emotions: if it is removed then there are no longer emotions of fearful behavior

suggesting that behavioral, autonomic, and hormonal emotional responses are somewhat under the influence of the central nucleus.

Question 13

Kluver-Bucy syndrome / Case

Answer 13

Syndrome: similar symptoms but also amnesia, aphasia (disrupted language), visual agnosia (disrupted ability to recognize objects)

WHEEN DAMAGE IS BOTH HEMISPHERES

CASE: Epilepticus patient developed this syndrome - which made weird behavior like eating paper towels, plans, urine, etc.

Question 14

Lateral nucleus is responsible for:

Answer 14

Learning stimulus that is threatning

Question 15

Olafactory system

Answer 15

The medial nuclei of the amygdala receive input from the olfactory cortex and olfactory bulb and play a role in the olfactory system.

(Pheremones chemical that carries messages from one animal to another)

Question 16

Hippocampal formation

Answer 16

For memory and learning

= Hippocampus and limbic cortex

Question 17

Hippocampal Formation - Anatomy

• Dentate gyrus
• Hippocampus proper
• Subiculum

Answer 17

A cross-section of the hippocampus shows the hippocampal formation: a composition of the dentate gyrus, CA fields* and subiculum

Intermediate layer:
- Excitatory pyramid cell neurons in the hippocampus and excitatory granule cells in the dentate gyrus: project axon to allow them to communicate

• The stratum lacunosum molecular (inner layer) of the hippocampus and the molecular layer of the dentate gyrus contain dendrites of pyramidal and granule cell

Question 18

Hippocampal formation (AFFERENT)

Answer 18

> Entorhinal cortex < receive signal from the amygdala, and processed sensory info.

Cia is the neighboring perirhinal cortex or the parahippocampal cortex.
>Alveus: medial entorhinal: axon to subiculum + CA1
>Perforant: Lateral entorhinal: all other sections of the hippocampus

Question 19

Hippocampal formation (EFFERENT)

Answer 19

Fornix: efferent pathway of the hippocampal: pyramid axon info to hypothalamic mamillary bodies

Question 20

Korsakoff syndrome

Answer 20

Chronic alcohol consumption.

Symptom: confabulation: by fabricating or guessing memory

Question 21

What influences consilidation?

Answer 21

Hippocampus efferent; influence memory consolidation

Question 22

Learning and memory

Answer 22

Declarative memory (explicit) memory refers to the conscious recollection of fact and experiences or event

Question 23

Consolidation

Answer 23

Encoding (Learning > Consolidation (memory) > Storage (memory) > Retrieval (memory)

Question 24

Consolidation in memory:

Answer 24

Memory is in episode instead of isolated memories: The order in which event occurred, the context in which a stimulus was encoded

Question 25

Flashbulb memories

Answer 25

Emotionally significant memories form quickly, e.g highly arousing event such as romantic encounters, danger, tragedy, etc

Question 26

Patient HM

Answer 26

Removed temporal lobe removed

• Surgery eliminated seizures but experienced amnesia.
• Non-Declarative (implicit) riding a bike
• Access to new memories but not old
• Hippocampus NOT THE SITE of long term memory
• Hippocampus for declarative memories