Thalamus and Limbic System

Question 1

Thalamic Relay (TR) Neurons

Answer 1

• located in thalamus
• receive input from sensory system
• relay sensory information to cortex via Glu in layer 4 of cortex
• ex. LGN and visual sense
• awake: ~-55mV, depolarized when neurons fire high frequency action potentials
• sleep: slow wave stage inhibits TR neurons by releasing GABA, ~85mV, fire in bursts of action on top of Ca++ spike (Ca spike happens with 3Hz frequency)

Question 2

T Type Ca Channel

Answer 2

• voltage gated
• found in thalamic relay neuron
• has activation gate (closed at /80mV) and inactivation gate (open at -80mV)
• movement of gates is very slow

Question 3

Optogenetics

Answer 3

• used in mouse models to control seizures

- channelrhodopsin: blue light opens and depolarizes cell

Question 4

Dorsomedian (DM) Nucleus of Thalamus

Answer 4

-to frontal associated cortex

Question 5

Anterior Nucleus of Thalamus

Answer 5

-to cingulate gyrus of cortex

Question 6

VA/VL Nucleus of Thalamus

Answer 6

-to motor cortex

Question 7

VPM/VPL Nucleus of Thalmus

Answer 7

-to somatosensory cortex

Question 8

Pulvinar Nucleus of Thalamus

Answer 8

-to parieto-occipital associated cortex

Question 9

LGN of Thalamus

Answer 9

• to visual cortex

- incoming optic tract

Question 10

MGN of Thalamus

Answer 10

• to auditory cortex

- incoming inferior brachium

Question 11

General Concepts of Thalamocortical Connections

Answer 11

• all connections are reciprocal

- R thalamus deals with L side of body and interacts with R cortex

Question 12

Centromedian Nucleus of Thalamus

Answer 12

-motor

Question 13

Reticular Nucleus of Thalamus

Answer 13

• a sheet of cells on lateral surface of thalamus

- primarily inhibitory interneurons with connections to all the other nuclei

Question 14

Papez Circuit

Answer 14

• limbic system circuit
• memory
• mammilary body -> anterior n. -> cingulate gyrus -> hippocampus (all connected by fornix?)

Question 15

Amygdala

Answer 15

• Limbic System Circuit
• emtion
• outputs: BNST, septal area, hypothalamus, thalamus
• involved in: fear, motivation, attention, sexual drive

Question 16

Output of Hippocampus

Answer 16

-CA1 and CA3 through the fornix (basis for long term memory consolidation)

Question 17

NMDA Receptors

Answer 17

• to open, requires tetanus and Ca

- involved in learning

Question 18

Condition Flavored Aversion

Answer 18

• applies to odor and taste

- novel stimulus paired with negative stimulus up to half an hour afterward will cause avoidance of novel stimulus

Question 19

Procedural Memory

Answer 19

• memory of how to accomplish tasks (motor memory)
• HM was not aware he had procedural memory
• frontal cortex, basal ganglia

Question 20

Feedforward Mechanisms

Answer 20

-predict appetitive v. aversive events and engage more complex behaviors accordingly

Question 21

Insula

Answer 21

• links between insula, VMPFC, and amygdala relate these senses to emotion
• constitues primary olfactory, gustatory, and visceral sensory cortex

Question 22

Channelrhodopsin-2

Answer 22

-Na/K channel

Question 23

Halorhodopsin

Answer 23

-Cl channel

Question 24

Amygdala

Answer 24

-links aversive and appetitive stimuli with physiologic responses, action patterns, perceptions, and predictions

Question 25

VMPFC and Ventral Striatum

Answer 25

-critical for generating and reinforcing predictions about risks and rewards associated with actions

Question 26

Ventral Tegmental Area (VTA)

Answer 26

- reward, punishment, salience in various subregions - releases DA in response to errors in predictions - signals contribute to synaptic plasticity and associative learning in the amygdala, ventral striatum, and VMPFC - VTA activation releases DA onto nucleus accumbens neurons, pleasure perceived and identifies stimulating activity as one to be repeated

Question 27

Iowa Gambling Task

Answer 27

- people with damaged orbitofrontal cortex had impaired ability to estimate the risk/reward associated with certain behaviors - implies suppression of behaviors felt to be excessively risky, esp in context of social situations (ex. "gut feeling")

Question 28

Mesolimbic Pathway

Answer 28

-subserve the integration of sensory input and motor responses with affective or emotional data

Question 29

Mesocortical Pathway

Answer 29

-involved in communication and social abilities

Question 30

Nigrostriatal Pathway

Answer 30

-part of basal ganglia (aka extrapyramidal tract) plays a central role in planned, coordinated movement

Question 31

Tuberoinfuncibular Pathway

Answer 31

-hypothalamic neurons release DA in pituitary to inhibit prolactin release

Question 32

Stria Terminalis

Answer 32

- a band of fibers running along the lateral margin of the ventricular surface of the thalamus - Serving as a major output pathway of the amygdala, the stria terminalis runs from its centromedial division to the ventral medial nucleus of the hypothalamus.

Question 33

Kluver Blucy Syndrome

Answer 33

- a syndrome resulting from bilateral lesions of the anterior temporal lobe (including amygdaloid nucleus) - may present with hyperphagia, hypersexuality, hyperorality, visual agnosia, and docility

Question 34

Red Nucleus

Answer 34

- projects to spine | - comes from contralateral cerebellum