Diencephalon

Question 1

Diencephalon is composed of:

Answer 1

1) Thalamus
2) Hypothalamus
3) Epithalamus
4) Subthalamus

Question 2

Massa Intermedia

Answer 2

1) Non-neuronal
2) Spans the 3rd ventricle & connects both thalami
3) Some people do not have, varies in size
4) Not a commissural pathway
5) no clinical significance when ablated

Question 3

Lentiform Nucleus is composed of

Answer 3

1) Putamen

2) Globus Pallidus

Question 4

Major Nuclei of Thalamus

Answer 4

1) Dorsomedial Nucleus
2) Anterior Nucleus
3) Ventral Anterior
4) Lateral Dorsal
5) Ventral Lateral
6) Lateral Posterior
7) Pulvinar
8) Medial Geniculate
9) Lateral Geniculate
10) Ventral Posterior (lateral & medial)

Question 5

External Medullary Lamina

Answer 5

1) Seperates Reticular nucleus from major nucleus of thalami

Question 6

Ventral Posterior Nucleus

Answer 6

1) Medial or Lateral
2) Involved in processing sensory w/Medial Lemniscus and ALS
- Pain & temp, General Tactile
- Fine touch
3) ML & ALS for body –> VPLN
- everything other than face innervated by trigeminal
- -> VPLN
4) ML & ALS of trigeminal–> VPMN

Question 7

Intralaminar Nucleus

Answer 7

1) Collection of nuclei in center of thalamus
2) 2 major nuclei
- Centromedial Nucleus- Pain
- Parafascicular Nucelus- Consciousness (alertnesss)

Question 8

Whats the largest nucleus of Thalamus?

Answer 8

Pulvinar

Question 9

Reticular Nuclei

Answer 9

1) Processess sensory

- filters out any signal that isn’t max

Question 10

What sensory info to thalamus

Answer 10

1) all sensory goes to thalamus except olfaction

Question 11

Sensory from Eyes: Pathway

Answer 11

1) Retina
2) Lateral Geniculate Nucleus
- will show up as optic radiations
3) Visual Cortex

Does not got thru thalamocortical tract

Question 12

Sensory from ears: Pathway

Answer 12

1) Cochlea
2) Cochlear Nucleus (in brainstem)
3) Medial Geniculate
- via coursing through the lateral lemnicus & inferior colliculus
4) heschl’s Gyrus (41 & 42)
- via thalamocortical tracts

Question 13

Inputs into Thalamus

Answer 13

1) Vestibular
2) Taste
3) Trigeminothalamic Tracts (VPMN)
4) Medial Lemniscus
5) Spinothalamic Tracts

Question 14

Motor System of thalamus

Answer 14

1) Motor nuclei
- Ventral Lateral
- Ventral Anterior
- influential in movement, don’t initiate
2) Project to premotor cx for processing
3) Thalamus interconnected to basal nuclei
- Premotor -> caudate & putamen
- caudate and putamen ->globus pallidus
* *bilateral communication via Lentiform Fasciculus and ansa leenticularis

Question 15

Motor System: Dental Nucleus

Answer 15

1) dentate nucleus of Cerebelum
- superior cerebellar peduncle major pathway out
- crosses at midbrain at the level of inferior colliculus
2) Red Nucleus (some synapse, some go thru)
3) If go thru:
- synapse onto ventral lateral nucleus
- via dentatothalamic tract which run through thalamic fasciculus

Question 16

Motor System: Substantia Nigra

Answer 16

1) Substantia Nigra–> Ventral Anterior Nucleus

- via thalamic fasciculus

Question 17

Lesion within any part of motor system results in:

Answer 17

1) No paralysis but uncoordinated movement

Question 18

Limbic System of Thalamus

Answer 18

1) Dorsal Medial Nucleus & Anterior Nucleus
2) Dorsal Medial Nucleus
- located only in humans and higher primates
- strong 2 way connection w/prefrontal cortex thru anterior limb of internal capsule
- influences mood and behavior
- project to future
3) anterior Nucleus projects to:
- cingulate gyrus–>emotion
- Hypothalamus (bidirectional)->ties emotion with autonomic system

Question 19

Thalamus: Cosciousness and alertness

Answer 19

1) Intralaminar Nucleus (major)

- receives input from ascending reticular formation and courses through Central Tegmental tract