Thalamus

Question 1

Nuclear groups of the thalams

Answer 1

Anterior
Medial (Dorsomedial)
Lateral
Posterior
Intralaminar
Other

Question 2

Anterior Nuclear Group

Answer 2

Anterior Nucleus:

afferents: Mammilothalamic tract, Hippocampal afferents via fornix
efferents: To Cingulate Gyrus

Question 3

Medial Nuclear Group

Answer 3

Dorsomedial nucleus

Amygdala and Olfactory Cortex –> DM –> Prefrontal cortex

Sub. Nigra pars Reticulata –> DM –> Frontal Eye feilds in Middle frontal gyrus. (Brodman 8)

Question 4

Posterior Nuclear Group

Answer 4

Pulvinar - Lateral Geniculate - Medial Geniculate

Question 5

Pulvinar connections

Answer 5

Association cortices –> Pulvinar –> Diffuse cortex projections

Retina –> Pulvinar –> Visual Association Cortex V2, V3
Superior Colliculus –> Pulvinar –> Visual Association Cortex, extrastriate cortices)
Both of the above are Extrageniculate Ocular Pathways

Question 6

Reticular Nucleus connections

Answer 6

Interthalamic connections, Reticular Nucleus links thalamic nuclei to one another.

It also recieves diffuse cortical afferents.

Question 7

Lateral Geniculate body connections

Answer 7

Retinal Ganglion cells –> LGB –> Primary visual cortex

Ipsilateral fibers (from ipsilateral temporal visual field) go to layers 2,3,5
Contralateral fibers (from contralateral nasal visual field) go to layers 1,4,6

Question 8

Medial Geniculate body connections

Answer 8

Inferior Colliculus –> MGB –> Primary Auditory cortex and Secondary auditory cortex B41 and B42.

Question 9

Lateral Nuclear Group

Answer 9

Lateral Dorsal Nucleus -  LD
Lateral Posterior Nucleus -  LP
Ventral Anterior -  VA
Ventral Lateral -   VL
Ventral Posteromedial -  VPM
Ventral Posterolateral -   VPL

Question 10

Ventral Anterior Nucleus connections

Answer 10

Medial Globus Pallidus and Sub. Nigra pars reticulata –> VA –> Premotor Cortex.

ARAS –> Intralaminar Thalamic Nuclei –> VA –> Diffuse Frontal Projections

Question 11

Intralaminar Nuclei connections

Answer 11

ARAS –> Rostral Intralaminar Nuclei –> VA thalamic nucleus

Question 12

Ventral Lateral Nucleus connections

Answer 12

Output nuclei of basal ganglia —> VL anterior portion –> Supplementary Motor Cortex

Contralateral Deep Cerebellar Nuclei –> VL posterior portions –> Premotor Cortex and Primary Motor Cortex.

Question 13

Lateral Dorsal Nucleus connections

Answer 13

Limbic lobe and Parietal region –> LD –> Cigulate Gyrus and Medial Parietal Cortex

Question 14

Lateral Posterior Nucleus connections

Answer 14

Superior Parietal Lobule –> LP –> Superior Parietal Lobule

Question 15

Ventral Postero Lateral Nucleus connections

Answer 15

Medial Lemniscus and Spinothalamic Tract –> VPL –> Primary and Secondary Somatosensory Cortex.

Question 16

Ventral Postero Medial Nucleus connections

Answer 16

Principle Sensory Nucleus of Trigeminal Nerve and the Spinal Trigeminal Nucleus (Dorsal Trigeminal Nucleus) => Trigeminal lemniscus
–>
VPM –> Primary Secondary Somatosensory Cortex

Nucleus of Solitary Tract (STN) –> VPM parvocellular cells –> Parietal Operculum taste area Brodman 43.

*The VPM/VPL has a somatotopic organization of corresponding neurons relaying the sensory afferents

Question 17

What are the intralaminar nuclei?

Answer 17

The Rostral Intralaminar Nuclei, don't need names
and the
Caudal Intralaminar Nuclei: 
1) the Parafascicular Nucleus
2) the Centromedian Nucleus

Question 18

Rostral Intralaminar Nuclei connections

Answer 18

Association cortices –> Pulvinar –> Diffuse cortex projections

Question 19

Caudal Intralaminar Nuclei connections

Answer 19

Medial/Internal Globus Pallidus –> Centromedian Nucleus (CM) –> Putamen and diffuse cortical

Median/Internal GP –> Parafascicular (PF) –> Caudate and diffuse cortical

Question 20

What are the major functional classifications of the thalamic nuclei?

Answer 20

Sensory Relay nuclei: VPL VPM, Lateral and medial geniculates.

Association nuclei: Dorsomedial Nuclei, Lateral Dorsal Nucleu, Lateral Posterior Nucleus, Pulvinar

Non-specific/diffuse nuclei: Midline and intralaminar nuclei

Nuclei not projecting to the cortex: Reticularis Nucleus, Parafascicularis, Subparafascicularis.