Limbic system

Question 1

paleocortex

Answer 1

• oldest “phylogentic” age

- associated with olfaction and contributes to survival behavior

Question 2

archicortex

Answer 2

• the hippocampus

- contributes to behavior through an organism’s ability to learn and remember significant events

Question 3

allocortex

Answer 3

• i think refers to the hippocampus and paleocortex

- usually are three-layered

Question 4

mesocortex

Answer 4

• typically 5 layered
• can be peri-allocortex (closer to the allocortex)
• can be pro-isocortex (closer to the isocortex)

Question 5

isocortex

Answer 5

• determined to be phylogenetically “newer”

- 6 layers

Question 6

Describe the Papez Limbic circuit

Answer 6

• hippocampus to the mamillary bodies (hypothalamus) via the fornix
• the mamillary bodies to the anterior thalamus via the mammillothalamic tract
• the anterior thalamus to the cingulate cortex via the thalamocortical projections
• the cingulate back to the hippocampal region

Question 7

What are the main problems with Papez’s limbic circuit

Answer 7

• the hippocampus is not a main regulator of the hypothalamus
• the hippocampus does provide important contextual information to emotional experience
• the hippocampus only has minor projections to area of the hypothalamus that are actually outside of the mammillary bodies

Question 8

Areas that are damaged in Korsakoff’s amnesia that indicates their importance in memory formation

Answer 8

-mammillary bodies and anterior thalamus

Question 9

Kluver-Bucy symptom

Answer 9

• visual agnosia
• hypersexuality
• hyperorality
• emotional blunting/placidity
• willingness to approach previously fearful stimuli

**later studies showed the importance of the amygdala

Question 10

amygadala

Answer 10

• key regulator of the hypothalamus

- is located deep within the temporal lobe

Question 11

the amgydala is essential for conditioned learning of:

Answer 11

-emotions… particularly fear

-

Question 12

the amygdala receives sensory information from the ____ and ____ into its ___ nucleus

Answer 12

• cortex and thalamus

- lateral

Question 13

the output of the amygdala arises mainly from the _____ and targets:

Answer 13

• central nucleus

- hypothalamus and the brainstem

Question 14

amygdala efferents:
periaqueductal gray to _____
lateral and paraventricular hypothalamus to regulate ____

Answer 14

• periaqueductal gray to regulate skeletomotor behaviors

- lateral and perivenricular hypothalamus to regulate autonomic and endocrine responses

Question 15

What did Joseph LeDoux demonstrate about the amygdala ?

Answer 15

• he found that certain sensory stimuli reach the amygdala directly by way of the thalamus before being routed through cortex (low road)
• more processed sensory information arrives from the cortex at a later time (high road)

Question 16

Cognitive behavioral therapy

Answer 16

• ability of cognitive reasoning to correct and reverse maladaptive emotions is the basis for this therapy
• ventromedial and orbital divisions of the prefrontal cortex can suppress emotional expression by inhibiting the amygdala output

Question 17

Describe the paradox of major depressive disorders

Answer 17

• early functional imaging studies showed reduced blood flow in orbitofrontal and cingulate regions. This correlated withb reduced gray matter volume in these regions.
• recent studies show that these areas are actually hyperactive in depression and they are targeted for therapy by deep brain stimulation

Question 18

orbitofrontal cortex

Answer 18

-helps to guide behavior based on past rewards and punishments

Question 19

damage to the oribitofrontal cortex would result in

Answer 19

-associated with blunted or inappropriate emotions
-poor judgement
often due to failure to inhibit maladaptive responses

Question 20

what were often performed on patients with violent mental illnesses to try to calm them down?

Answer 20

-frontal lobotomies and cingulatomies

Question 21

Targeted cingulatomies are still performed in cases of:

Answer 21

• medically intractable obsessive compulsive disorder
• chronic pain syndromes
• refractory depression or bipolar disorder

Question 22

cingulate gyrus

Answer 22

• lies immediately above the corpus collosum
• is visceromotor
• can produce some somatic function and even produce aggressive reactions
• major area involved in conscious perception of pain and other emotions

Question 23

septum

Answer 23

-a telencephalic structure lying beneath the corpus callosum
-inputs: hippocampus and cingulate cortex
-projections: amygdala, hypothalamus, and brainstem
lesions alter aggressive and sexual behaviors

Question 24

nucleus accumbens

Answer 24

• ventral extension of the striatum
• limbic-motor interface
• processes limbic cortical input and provides adaptive motor strategies for motivated behaviors

Question 25

visceral sensory input to the hypothalamus and amygdala arises from

Answer 25

-nucleus of the solitary tract

Question 26

multimodal processed sensory input derives from association cortices to:

Answer 26

-amygdala, hippocampal region, cingulate and prefrontal cortex

Question 27

motor output of the limbic system:

visceral motor

Answer 27

visceral motor output originates from the hypothalamus and amygdala to brainstem autonomic centers

Question 28

somatic motor output of the limbic system

Answer 28

-comes from prefrontal to premotor cortex
-it is relayed through the basal ganglia nucleus accumbens
aka the limbic motor interface