Subcortical Gray Flashcards
The medial wall of the diencephalon forms the borders of what ventricle?
3rd
What are the components of the diencephalon?
Epithalamus: Stria Medullaris Thalami, Habenular Nuclei and Pineal Gland
Thalamus and metathalamus (MGB, LGB)
Subthalamus: Subthalamic nucleus, Fields of forel, Zona incerta
Hypothalamus
The stria medullaris thalami connects which structures?
Olfactory area with the habenular nuclei
What is the function of the habenular nuclei?
Emotion and behaviour
Receive stria medullaris thalami and project to the interpeducnular nucleus of the midbrain
How is puberty affected by pinealoma vs destruction of pineal gland?
Pinealoma results in delay of puberty
Destruction results in precocious puberty
PG exerts an inhibitory function to gonadal function
What are the functions of the ff sections of the thalamus?
- Anterior nuclear group
- Dorsomedial group
- Pulvinar with the lateral posterior group
- Ventral Anterior and ventral lateral
- 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
- Dorsomedial group: Behavior, decision making, memory– bilateral lesions makes a patient apathetic and indifferent
- 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
- 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
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.
Dorsomedial– also, poorly localized pain with emotional quality with the dorsomedial nucleus (surgical lesion in the area of IL may provide pain relief)
What are the functions of the ff sections of the thalamus?
- Ventral posterior medial
- Ventral posterior lateral
- Intralaminar nuclei (centromedian, paracentral, centromedial)
- Metathalamus
- Ventral posterior medial: Receives trigeminal and taste fibers
- Ventral posterior lateral: Receives medial lemniscus and spinothalamic tracts
- 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)
- Metathalamus: MGB and LGB with auditory and visual functions
Where are the primary afferents of the ventral anterior and ventral lateral thalamic nuclei?
A: Globus pallidus
L: Deep cerebellar nuclei mainly the dentate
What thalamic nuclei are known as the multimodal association nuclei?
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
Most inputs to the thalamus facilitate both projection and local circuit neurons using glutamate or aspartate, EXCEPT FOR?
Basal ganglia inputs which is inihibitory with GABA
What important fibers pass through
- Anterior limb of the IC
- Genu
- Posterior limb of the IC
- Sublenticular part
- Retrolenticular part
- Anterior limb of the IC: Frontopontine, thalamocortical and corticothalamic fibers
- Genu: Corticobulbar fibers
- Posterior limb of the IC: Corticospinal, corticorubral, thalamocortical and corticothalamic fibers
- Sublenticular part: Auditory radiation and visual radiation
- Retrolenticular part: Visual radiation, cortico nigral
Identify which artery supplies the following parts of the thalamus:
- Posterolateral: VPL, VPM, Pulvinar, reticular nuclei are ALL here!
- Anterolateral
- Medial
- Lateral
- Posterior
- Posterolateral: Thalmogeniculate– PCA
- Anterolateral: Polar (Tuberothalamic)– PComm
- Medial: Thalamoperforating (Paramedian)– Basilar root of PCA
- Lateral: Anterior choroidal– ICA
- Posterior: Posterior choroidal– PCA
What is the blood supply of the IC?
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
All somatic and special senses pass through the thalamus before going to the cortex except for:
Olfaction