Limbic System

Question 1

What path does the fornix take?

Answer 1

From the hippocampus to the mamillary body, sepal nuclei.

Question 2

What tract travels from the body of the mamillary body to the anterior thalamic nucleus?

Answer 2

Mamillo-thalamic tract

Question 3

What travels from the amygdala to the septal nuclei?

Answer 3

Stria terminalis

Question 4

What travels from the midbrain to the forebrain via the hypothalamus?

Answer 4

Medial forebrain bundle

Question 5

What travels from the hypothalamus to the brainstem and spinal cord, giving off branches to the pons, medulla, and spinal cord?

Answer 5

Dorsal longitudinal fasciculus

Question 6

Where does norepinephrine in the limbic system come from?

Answer 6

Locus ceruleus (LC) in the pons

Question 7

Where does serotonin (5HT) in the limbic system come from?

Answer 7

Raphe nuclei (Ra) in the midbrain, pons, and medulla

Question 8

What region in the mesolimbic system is associated with dopamine?

Answer 8

Ventral tegmental area (VTA); just medial to the substantia nigra. Axons from nucleus accumbens, medial prefrontal cortex, amygdala, & septal nuclei zip through here.

Question 9

What do cocaine and amphetamines do to dopamine levels?

Answer 9

-Cocaine blocks dopamine reuptake, thus increasing the concentration in the synaptic cleft. —Amphetamine blocks dopamine reuptake as well as promote secretion of dopamine.

Question 10

What neurotransmitter is associated with nucleus basalis and septal nucleus?

Answer 10

Acetylcholine. In alzheimers, Nucleus Basalis is lost, memory deficits. Acetylcholine is important in memory.

Question 11

What happens to learned and conditioned behavior if the amygdala is lesioned?

Answer 11

No conditioning can happen and there is immediate extinction of learned behavior.

Question 12

What symptoms are seen in a prefrontal lobe syndrome?

Answer 12

• Impairment in goal directed behavior
• Lack of emotion in decision-making (lack of risk aversion)
• Poor social judgement (antisocial behavior)
• Poor emotional control (increased impulsivity)

Question 13

What does the dorsolateral prefrontal cortex (DLPFC) play a major role in?

Answer 13

Working memory

Question 14

Why does the orbital frontal cortex play a major role in prefrontal lobe syndrome?

Answer 14

It is connected to the amygdala, inhibiting it. Without it, more prone to fits of emotion. Prefrontal cortex is inhibitory to the amygdala, which is excitatory on the hypothalamus.

Question 15

What is the hippocampus important in?

Answer 15

Memory consolidation, specifically explicit or declarative memory.

Question 16

What is anterograde amnesia?

Answer 16

No new memories

Question 17

What is temporally graded retrograde amnesia?

Answer 17

You can’t remember past events well in a graded fashion; recent past events are harder to recall then events long ago.

Question 18

Differentiate between semantic and episodic memories.

Answer 18

Semantic- facts
Episodic- experiences
*Hippocampus is needed for this

Question 19

What types of memory is the hippocampus not needed for?

Answer 19

Procedural or nondeclarative/implicit AKA motor memory

Question 20

What disease is indicative of:

• impaired recognition of emotions (fear and anger)
• Memory loss especially w/emotional content

Answer 20

Urbach-Wiethe disease (bilateral damage due to mineral deposit in amygdala)

Question 21

1. Re-experiencing phenomena i.e. flashbacks
2. Avoidance of situations that parallel initial trauma
3. Hyperarousal i.e. increased anxiety..hallmark

Answer 21

Post Traumatic Stress Disorder (PTSD)

-Hyperactivity of amygdala, little inhibition by medial prefrontal cortex

Question 22

Fragmentation of mood, thought, and action.
Positive symptoms: Delusions, hallucinations
Negative symptoms: Social withdrawal

Answer 22

Schizophrenia (1% of U.S. population)

Question 23

What is the dopamine hypothesis of schizophrenia?

Answer 23

There is an increase in DA receptor activity.

-Amphetamine psychosis from taking amphetamines too long, lots of DA

Question 24

Treatments of schizophrenia?

Answer 24

Haloperidol: D2 receptor blocker. Causes Parkinson like disorder

Clozapine (atypical anti-psychotic):

1. D2 receptor blocker, but leaves receptor fast
2. 5HT receptor blocker
3. Blocks glutamate reuptake, thus increased glutamate

Question 25

What is the glutamate hypothesis of schizophrenia?

Answer 25

Phencyclidine (PCP) aka angel dust blocks NMDA receptor, thus decreasing glutamate and causing psychotic symptoms. Treat by increasing glutamate.

Question 26

What are the symptoms of depression?

Answer 26

-Anhedonia: loss of interest in pleasurable/rewarding behaviors
-Sleep wake problems
-Social withdrawal
20% of women, 13% of men

Question 27

What are the treatments for depression?

Answer 27

Treat decreased NE and or 5HT receptor activity:

• Monoamine oxidase inhibition
• Tricyclics (Imipramine): blocks reuptake of NE and 5HT
• Serotonin specific reuptake inhibitors (SSRIs) e.g. fluoxetine

Question 28

• Disorder of immediate memory
• Disorientation
• Confabulation

*Damage to mamillary bodies or mamillo-thalamic tract

Answer 28

Korsakoff’s syndrome

-Chronic alcoholism associated with this because it ultimately leads to a vitamin b1 deficiency

Question 29

• Oral tendencies
• Changes in emotions (even keel, nothing bothers them due to loss of amygdala)
• Hypersexuality (increased number and variety of sexual activities due to loss of pathways to hypothalamus)
• Visual agnosia (AKA psychic blindness. Inability to discriminate visual stimuli due to lost input from visual cortex.)

Answer 29

Kluver-Bucy Syndrome: bilateral medial temporal lobe damage.

Question 30

• Memory loss
• Mood changes: anxiety and depression
• Motor dysfunction
• Complete loss of cognitive function

Answer 30

Alzheimers Disease (over 50% of ppl over 85)

• loss of chlinergic input to hippocampus (antiacetylcholinesterases? don’t work well)
• Loss of neurons in multiple brain areas
• Presence of NFT and beta amyloid plaques

Question 31

What disease is caused by repeated head trauma and mimics prefrontal cortex damage?

Answer 31

Chronic traumatic encephalopathy (CTE)