Thalamus

Question 1

Epithalamus

Answer 1

PINEAL and HABENULAR

Pineal: endocrine organ, releases melatonin, controlled by sympathetics

Habenular nuclei: Limbic relay nuclei goes into brain stem
-“negative reward” by suppressing mesolimic dopamine reward

Question 2

Dorsal Thalamus

Answer 2

Primary site of relay for all sensory pathways to cerebral cortex

ALSO site of RELAY for cerebellar and basal ganngliar feedback to cortex

Almost all thalamic nuclei project into cortex
Each nucleus receives reciprocal connections from cortex

Question 3

Internal Medullary Lamina

Answer 3

Splits thalamus

Intra laminar nuclei

Question 4

Medial Geniculate

Answer 4

Hearing relay

Tonotopically organized input from inferior colliculus

Question 5

Types of Thalamic Input

Answer 5

1. Input relayed to cortex

2. Modulatory input pathways that effect transmission

Question 6

Thalamic Modulation

Answer 6

Each nuclei contains many inhibitory interneurons (GABA and peptidergic)

Neuromodulatory neurotransmitter systems terminate in nuclei

Question 7

Two states of thalamic projection neurons

Answer 7

1. Tonic mode

2. Burst/oscillatory mode

Question 8

Tonic Mode

Answer 8

Neurons respond normally to stimuli (i.e. Depolarization and hyperpolarization)

Question 9

Burst mode

Answer 9

Tonically hyperpolarized

T CALCIUM CHANNELS open

-> depolarization and burst of potentials

State of intrinsic rhythmicity

BURST neurons can’t communicate specific information

Question 10

Anterior Thalamus

Answer 10

One nuclei

Question 11

Medial Thalamus

Answer 11

Medial Dorsal Nucleus

Midline nuclei

Question 12

Lateral Region

Answer 12

Ventral:

• V. Posterior (Medial and Lateral)
• V. Lateral
• V. Anterior

Lateral:

• Pulvinar
• L. Posterior
• L. Dorsal

Question 13

Diencephalon

Answer 13

Thalamus, epi thalamus, hypothalamus

Question 14

Metathalamus

Answer 14

Posterior of Pulvinar

Medial Geniculate Body (auditory relay)

Lateral Geniculate Body (visual relay)

Question 15

4 types of thalamic nuclei

Answer 15

1. Relay
2. Association
3. Nonspecific
4. Reticular Thalamic

Question 16

Relay Nuclei

Answer 16

nuclei that receive well defined input from a specific nucleus and project to distinct cerebral cortical targets

Primary sensations: VPL, VPM, MG, LG

Cerebellar relay: VL

Basal ganglia: VL, VA

Question 17

VPL and VPM

Answer 17

Somatosensory relay

VPL = medial lemniscal and spinothalamic connections

VPM = Trigeminal input

Question 18

Lateral Geniculate

Answer 18

Vision relay

Retinotopic input from optic tract from contralateral visual world

Question 19

VL

Answer 19

Input from cerebellum, mainly dentate nucleus

Projects to primary motor cortex

Question 20

VA

Answer 20

Input from basal ganglia

Projects to premotor cortex

Involved in planning and initiating movements

Question 21

Association nuclei

Answer 21

Largest is up