Limbic system & amygdala

Question 1

Which two gyri make up Broca’s original “Limbic Lobe”?

Answer 1

Cingulate Gyrus and Parahippocampal Gyrus

Question 2

Which experimental condition is characterized by spontaneous anger, elevated heart rate, and pupil dilation in cats?

Answer 2

Sham Rage

Question 3

In Phillip Bard’s 1928 study, Sham Rage occurred when the cerebral hemispheres were removed but which structure was left intact?

Answer 3

Hypothalamus

Question 4

What were the results of stimulating the hypothalamus in awake cats (Walter Hess)?

Answer 4

Rage, defensive posture, or sleep (depending on location)

Question 5

What is the primary output pathway from the Hippocampus in the Papez circuit?

Answer 5

Fornix

Question 6

The Fornix connects the Hippocampus to which structure?

Answer 6

Mammillary bodies

Question 7

Which tract connects the Mammillary bodies to the Anterior Thalamus?

Answer 7

Mammillothalamic tract

Question 8

The Anterior Nucleus of the Thalamus projects to which cortical structure?

Answer 8

Cingulate Gyrus

Question 9

Which structure completes the circuit by connecting the Cingulate Gyrus back to the Hippocampus?

Answer 9

Entorhinal cortex (via Parahippocampal gyrus)

Question 10

What is the primary function of the Amygdala regarding sensory experience?

Answer 10

Attaches emotional significance to it

Question 11

The Amygdala plays a key role in what specific type of learning?

Answer 11

Aversive Learning

Question 12

What syndrome results from the bilateral removal of the medial temporal lobes (Amygdala + Hippocampus)?

Answer 12

Kluver-Bucy Syndrome

Question 13

What are the classic symptoms of Kluver-Bucy Syndrome?

Answer 13

Hyperorality, Hypersexuality, Placidity (no fear/anger), Visual Agnosia, Amnesia

Question 14

In Downer’s split-brain monkey study, which side failed to show rage to threatening visual stimuli?

Answer 14

The side without the Amygdala

Question 15

In LeDoux’s fear conditioning studies, which pathway allowed fear conditioning even after the auditory cortex was severed?

Answer 15

Medial Geniculate Nucleus (MGN) → Amygdala

Question 16

Which genetic disease did patient SM have?

Answer 16

Urbach-Wiethe disease

Question 17

What was the specific nature of SM’s brain damage?

Answer 17

Bilateral calcification/damage to the Amygdala

Question 18

Patient SM had a specific impairment in recognizing which facial expression?

Answer 18

Fear

Question 19

Did Patient SM exhibit fear responses to external threats (snakes, spiders, haunted houses)?

Answer 19

No

Question 20

What stimulus did successfully evoke panic/fear in Patient SM?

Answer 20

Inhalation of 35% CO2​ (internal threat)

Question 21

What does the CO2​ study suggest about the Amygdala’s role in fear?

Answer 21

Required for external threats, but NOT for internally triggered fear/panic

Question 22

Which cortical areas are responsible for the conscious experience of emotion?

Answer 22

Orbital and Medial Prefrontal Cortex

Question 23

Which brain region is associated with the “Reward System”?

Answer 23

Ventral Basal Ganglia (Ventral Striatum)

Question 24

What condition is linked to dopaminergic dysregulation in the Ventral Striatum?

Answer 24

Addiction

Question 25

What is the function of the Mediodorsal (MD) Nucleus of the Thalamus in the limbic system?

Answer 25

Reward devaluation (satiety)

Question 26

Which brain structure activates during uncertainty surrounding suspicion?

Answer 26

Parahippocampal Gyrus

Question 27

Which brain structure activates when a subject is suspicious of another?

Answer 27

Amygdala

Question 28

Damage to the Parahippocampal Cortex (PHC) results in indifference to what auditory stimulus?

Answer 28

Dissonant (unpleasant) music

Question 29

Which brain regions show increased activity in response to untrustworthy faces?

Answer 29

Amygdala & Insula

Question 30

A "Volitional" (Pyramidal) smile is controlled by which pathway?

Answer 30

Motor Cortex / Pyramidal tract

Question 31

A "Spontaneous/Emotional" (Extrapyramidal) smile is controlled by which pathway?

Answer 31

Limbic / Extrapyramidal network

Question 32

A patient who can smile naturally at a joke but cannot smile on command likely has damage to which system?

Answer 32

Pyramidal (Motor) system

Question 33

A patient who can smile on command but has a flat face when laughing likely has damage to which system?

Answer 33

Extrapyramidal (Limbic) system

Question 34

Which two brain structures show smaller volume in veterans with PTSD?

Answer 34

Amygdala and Hippocampus

Question 35

Is the smaller amygdala volume in PTSD caused by trauma load or chronicity?

Answer 35

No (likely a pre-existing vulnerability)