Subcortical Gray

Question 1

The medial wall of the diencephalon forms the borders of what ventricle?

Answer 1

3rd

Question 2

What are the components of the diencephalon?

Answer 2

Epithalamus: Stria Medullaris Thalami, Habenular Nuclei and Pineal Gland
Thalamus and metathalamus (MGB, LGB)
Subthalamus: Subthalamic nucleus, Fields of forel, Zona incerta
Hypothalamus

Question 3

The stria medullaris thalami connects which structures?

Answer 3

Olfactory area with the habenular nuclei

Question 4

What is the function of the habenular nuclei?

Answer 4

Emotion and behaviour

Receive stria medullaris thalami and project to the interpeducnular nucleus of the midbrain

Question 5

How is puberty affected by pinealoma vs destruction of pineal gland?

Answer 5

Pinealoma results in delay of puberty
Destruction results in precocious puberty

PG exerts an inhibitory function to gonadal function

Question 6

What are the functions of the ff sections of the thalamus?

1. Anterior nuclear group
2. Dorsomedial group
3. Pulvinar with the lateral posterior group
4. Ventral Anterior and ventral lateral

Answer 6

1. Anterior nuclear group: Emotion and behaviour and memory– damage may result in episodic long term memory with sparing of the short term memory and intellectual capacities
2. Dorsomedial group: Behavior, decision making, memory– bilateral lesions makes a patient apathetic and indifferent
3. Pulvinar with the lateral posterior group: Selective visual attention with connections with the LGB and s colliculi and cortical association areas– also with speech mechansims
4. Ventral Anterior and ventral lateral: known together as the “motor thalamus” Regulation of movement with connections with the basal ganglia– control of head, eye, neck and body movements BASIS FOR THALAMOTOMY FOR MOVEMENT DISORDERS like tremor

Question 7

Disconnection of the prefrontal cortex by prefrontal leukotomy disconnects the prefrontal cortex from what nucleus of the thalamus? This used to be done to relieve sever anxiety states.

Answer 7

Dorsomedial– also, poorly localized pain with emotional quality with the dorsomedial nucleus (surgical lesion in the area of IL may provide pain relief)

Question 8

What are the functions of the ff sections of the thalamus?

1. Ventral posterior medial
2. Ventral posterior lateral
3. Intralaminar nuclei (centromedian, paracentral, centromedial)
4. Metathalamus

Answer 8

1. Ventral posterior medial: Receives trigeminal and taste fibers
2. Ventral posterior lateral: Receives medial lemniscus and spinothalamic tracts
3. Intralaminar nuclei (centromedian, paracentral, centromedial): Along with reticular nuclei mediates cortical arousal response; alone also plays a role in motor control and pain modulation– poorly localized pain with emotional quality with the dorsomedial nucleus (surgical lesion in the area of IL may provide pain relief)
4. Metathalamus: MGB and LGB with auditory and visual functions

Question 9

Where are the primary afferents of the ventral anterior and ventral lateral thalamic nuclei?

Answer 9

A: Globus pallidus
L: Deep cerebellar nuclei mainly the dentate

Question 10

What thalamic nuclei are known as the multimodal association nuclei?

Answer 10

Dorsomedial, Pulvinar and lateral posterior complex– no direct inputs from the long tracts main inputs are from other thalamic nuclei then project mainly to the association cortices

Question 11

Most inputs to the thalamus facilitate both projection and local circuit neurons using glutamate or aspartate, EXCEPT FOR?

Answer 11

Basal ganglia inputs which is inihibitory with GABA

Question 12

What important fibers pass through

1. Anterior limb of the IC
2. Genu
3. Posterior limb of the IC
4. Sublenticular part
5. Retrolenticular part

Answer 12

1. Anterior limb of the IC: Frontopontine, thalamocortical and corticothalamic fibers
2. Genu: Corticobulbar fibers
3. Posterior limb of the IC: Corticospinal, corticorubral, thalamocortical and corticothalamic fibers
4. Sublenticular part: Auditory radiation and visual radiation
5. Retrolenticular part: Visual radiation, cortico nigral

Question 13

Identify which artery supplies the following parts of the thalamus:

1. Posterolateral: VPL, VPM, Pulvinar, reticular nuclei are ALL here!
2. Anterolateral
3. Medial
4. Lateral
5. Posterior

Answer 13

1. Posterolateral: Thalmogeniculate– PCA
2. Anterolateral: Polar (Tuberothalamic)– PComm
3. Medial: Thalamoperforating (Paramedian)– Basilar root of PCA
4. Lateral: Anterior choroidal– ICA
5. Posterior: Posterior choroidal– PCA

Question 14

What is the blood supply of the IC?

Answer 14

Caudal portion is anterior choroidal from the ICA
Anterior limb striate branches of ACA and MCA
Genu striate branches of the MCA and ICA
Posterior limb striate branches of the MCA

Question 15

All somatic and special senses pass through the thalamus before going to the cortex except for:

Answer 15

Olfaction

Question 16

What type of pain terminates at the thalamus?

Answer 16

Burning acing type of pain carried by the C fibers

Question 17

What is post stroke thalamic syndrome?

Answer 17

Higher threshold for stimuli but sensations are exaggerrated and unpleasant when perceived

Question 18

Pain mediated through the dorsomedial nucleus of the thalamus projects to what cortical structure?

Answer 18

Anterior cingulate cortex

Question 19

What kind of neurons associated with processing of painful stimuli can be found in the ventral posterior infereior nucleus?

Answer 19

Wide dynamic range type

Question 20

Why does damage to the STN result in hemiballismus?

Answer 20

It functions to stimulate (glutamate) the inhibitor (GPi and SNr) of the thalamus resulting in inhibition of the cortical motor areas.

Without a functioning indirect pathway there would be no inhibition from the basal ganglia only stimulation from the direct pathway.

Question 21

Which fibers are in?

1. H2 field of Forel
2. Lenticular fasciculus
3. Ansa Lenticularis
4. H field pre rubral filed forel
5. H1 field of forel
6. Thalamic fasciculus

Answer 21

1. H2 field of Forel: Same as #2– Pallidothalamic fibers going dorsal to the STN (Globus pallidus to the ventral anterior nucleus of the thalamus)
2. Lenticular fasciculus
3. Ansa Lenticularis: Pallidothalamic fibers looping around the internal capsule
4. H field pre rubral filed forel: Pallidothalamic and cerebellothalamic fibers (crosses the red nucleus)
5. H1 thalamic fasciculus field of forel: Pallidothalamic and cerebellothalamic fibers more distal (nearer the thalamic nuclei)
6. same as 5

Question 22

Most infarcts of the thalamus are located where?

Answer 22

Posterolateral (thalamogeniculate a from PCA) and medial thalamic territories (paramediam/thalamoperforating a. from the basilar root of the PCA)

Question 23

What type of pain is seen in the Dejerine Roussy thalamic syndrome?

Answer 23

severe persistent paroxysmal pain; sensitive to stimuli resulting in pain that outlasts the stimulus; ANESTHESIA DOLOROSA, painful anesthesia

Question 24

Which thalamic infarct primarily results in:

1. Pansensory loss
2. Severe neuropsych disturbance
3. Drowsiness
4. Hemiparesis with dysarthria
5. Homonymous quadrantanopsia

Answer 24

1. Pansensory loss: Postero lateral– thalamogeniculate a. from the PCA
2. Severe neuropsych disturbance: Antrolateral–Polar a. from the PComm
3. Drowsiness: Medial– Paramedian/ thalamoperforating from the basilar root of the PCA– affecting centromedian and dorsomedial nuclei
4. Hemiparesis with dysarthria: Lateral– ICA involvement
5. Homonymous quadrantanopsia: Posterior– invovlement of the LGB– Posterior choroidal of the PCA involvement

Question 25

The Klein Levin syndrome is due to infarct of? Manifests as?

Answer 25

``` Medial thalamus 1. Hyeprsomnia 2. Bulimia syndrome 3. Hypersexual 4. Excessive food intake 5. Childish behavior Like Horny old fat man ``` CONTRAST with the Kluver Blucy syndrome due to damage of bilateral temporal lobes 1. Excessive oral tendencies with an urge to put all kinds of objects into the mouth 2. Hypermetamorophosis (a need to explore everything) 3. Memory loss 4. Extreme sexual behavior 5. Indifference, placidity, 5. Visual agnosia (difficulty identifying and processing visual information) 6. Almost uncontrollable appetite for food may also be noted. Like Rike from Tokyo Ghoul MAIN DIFFERENCE: Hyperorality (not just food!!), Indifference and hypermetaorphosis with visual agnosia in KB

Question 26

What is the thalamic pain syndrome 1. Pure ALGETIC, intact SSEP 2. NO central pain (analgetic type), SSEP ABSENT, lost vibration and pain sense 3. Algetic as well but with decreased SSEP 2. With central pain and temperature sense-- vibration lost-- SSEP lost

Answer 26

1: PURELY ANALGETIC No central pain, no vibration or pain sense, absent SSEP 2. With central pain, no vibration but with pain, absent SSEP 3. With central pain, with both vibration and pain sense, reduced SSEP 4. PURELEY ALGETIC With central pain, with both vibration and pain sense with normal SSEP

Question 27

What higher cortical functions can be deranged with thalamic injury?

Answer 27

1. Memory: intralaminar, anterior, dorsomedial, mamillothalamic tract 2. Arousal 3. Alien hand syndrome: Anterolateral and posterolateral thalamus 4. Acalculia: left anterolateral territory 5. Language (anomia and transcortical aphasia): Dominant hemisphere thalamic lesions

Question 28

What are the anatomic parts of the basal ganglia?

Answer 28

Caudate Putamen Globus pallidus Nucleus accumbens septi Olfactory tubercle Physiologic: includes the subthalamic nucleus and substantia nigra

Question 29

In Huntington disease, what abnormality of the basal ganglia is seen relating to the ventricles?

Answer 29

The bulge of the caudate in the anterior horn of the lateral ventricle is lost

Question 30

What composes the ventrial striatum? Corpus striatum?

Answer 30

VS: Caudate, Putamen, Nucleus accumbens, Olfactory tubercle The ventral striatum is AKA as the limbic striatum! CS: Caudate, Putamen, Globus pallidus NB: Dorsal striatum, Striatum, Neostriatum

Question 31

Re: Striatum-- Striosomes or Matrix 1. Light staining for Acetylcholinesterase 2. GABA neurotransmitter 3. Output to nigra pars compacta 4. Output to nigra par reticularis 5. D1 dopamine receptor 6. D2 dopamine receptor

Answer 31

1. Light staining for Acetylcholinesterase: Striosome 2. GABA neurotransmitter: Both 3. Output to nigra pars compacta: Striosome 4. Output to nigra par reticularis: Matrix 5. D1 dopamine receptor: Striosome 6. D2 dopamine receptor: Matrix

Question 32

What are the two cell types in the striatum?

Answer 32

Spiny neurons-- 96% and aspiny neurons

Question 33

What 3 groups of neurons of the basal ganglia circuit use glutamate? Which ones secrete GABA?

Answer 33

Glu: STN, Thalamic, Cortex GABA: Globus pallidus externa, Substantia nigra pars reticulata, Globus pallidus externa

Question 34

Which artery supplies tail of the caudate caudal putamen Medial globus pallidus

Answer 34

Choroidal a. ICA

Question 35

Which artery supplies Caudate head and body Rostral putamen Lateral globus pallidus

Answer 35

Middle cerebral, lateral striate branches

Question 36

What specific area is affected in Huntington chorea? How about athetosis?

Answer 36

Caudate results in decrease in the indirect pathway output resulting in less thalamic inhibition Putamen

Question 37

What areas of the brain are small in Tourette syndrome patients?

Answer 37

Caudate and lenticular nucleus