Ask and ye shall receive: here is an #EndNeurophobia #tweetorial on the
THALAMUS
as requested by: @NMNeurons thank you!!
#medtwitter #MedStudentTwitter #NeuroTwitter @DxRxEdu @CPSolvers @AANMember @Tracey1milligan @MedTweetorials
THALAMUS
as requested by: @NMNeurons thank you!!
#medtwitter #MedStudentTwitter #NeuroTwitter @DxRxEdu @CPSolvers @AANMember @Tracey1milligan @MedTweetorials
I ❤️ neuro tweeting but pls also check out rest of my feed seeking to amplify voices I’m learning from on path to being an antiracist ally
follow @BlackInNeuro @LashNolen @uche_blackstock @DrOniBee
listen @thepraxispod @thenocturnists
read @dereckwpaul nejm.org
follow @BlackInNeuro @LashNolen @uche_blackstock @DrOniBee
listen @thepraxispod @thenocturnists
read @dereckwpaul nejm.org
Thalamus = deep gray matter structure, one of the few that is NOT part of the basal ganglia. It sits on each side of the third ventricle.
Although not readily apparent in our usual axial views of MRI, the thalamus sits just superior to the midbrain...
Although not readily apparent in our usual axial views of MRI, the thalamus sits just superior to the midbrain...
If the brainstem were an icecream cone with several scoops, cone = spinal cord, and from bottom to top scoops are medulla, pons, midbrain and then thalami sit just on top (hence term mesencephalic-diencephalic junction for midbrain-thalamus)
Thalamus=collection of nuclei (neuro-nerd nuclei= clusters of cell bodies, not site of DNA) that serve as nodes in circuits en route to cortex. It is the gateway of sensory info to consciousness, participates in motor loops, cognition, consciousness...EVERYTHING!
The most clinically relevant nuclei can be divided into SENSORY
MOTOR CONTROLÂ
COGNITION
CONSCIOUSNESS/AROUSAL
MOTOR CONTROLÂ
COGNITION
CONSCIOUSNESS/AROUSAL
Sensory:
VPL=somatosensory from BODY (dorsal column/spinothalamic->VPL->postcentral gyrus)
VPM=somatosensory from FACE (trigeminal pathways->VPM->postcentral gyrus)
LGN= VISUAL (CN 2->chiasm->tract->LGN->radiations->occipital cortex)
VPL=somatosensory from BODY (dorsal column/spinothalamic->VPL->postcentral gyrus)
VPM=somatosensory from FACE (trigeminal pathways->VPM->postcentral gyrus)
LGN= VISUAL (CN 2->chiasm->tract->LGN->radiations->occipital cortex)
Sensory (cont)
MGN= AUDITORY(CN8->auditory pathway->inf colliculus->MGN->sup temp gyrus)
Pulvinar= VISUAL ATTENTION (sup collic->pulvinar->occip/parietal cortices) *Neuro Boards/RITE favorite
MGN= AUDITORY(CN8->auditory pathway->inf colliculus->MGN->sup temp gyrus)
Pulvinar= VISUAL ATTENTION (sup collic->pulvinar->occip/parietal cortices) *Neuro Boards/RITE favorite
MOTOR CONTROL
VL/VA: Motor cortex->Basal ganglia-> VL/VA->motor regions and
cerebellum->superior cerebellar peduncle->VL->motor regions
see prior tweetorials on these circuits
medtweetorials.com
VL/VA: Motor cortex->Basal ganglia-> VL/VA->motor regions and
cerebellum->superior cerebellar peduncle->VL->motor regions
see prior tweetorials on these circuits
medtweetorials.com
COGNITION:
Anterior nucleus: MEMORY=
PAPEZ circuit: hippocampus->fornix->mamillary bodies-> Ant nuc=>ant cingulate->entorhinal ctx->hippocampus
Anterior nucleus: MEMORY=
PAPEZ circuit: hippocampus->fornix->mamillary bodies-> Ant nuc=>ant cingulate->entorhinal ctx->hippocampus
CONSCIOUSNESS/AROUSAL
Thalamus important node from RAS to hemispheres
Mediodorsal
Centromedian
Reticular
Intralaminar
ALL receive projections from Cortex, RAS, other thalamic nuclei and project to cortex, EXCEPT reticular nuclei, which project to other thalamic nuclei
Thalamus important node from RAS to hemispheres
Mediodorsal
Centromedian
Reticular
Intralaminar
ALL receive projections from Cortex, RAS, other thalamic nuclei and project to cortex, EXCEPT reticular nuclei, which project to other thalamic nuclei
In general thalamus supplied by posterior circulation- PCA + branches... want more detail? check out amazing paper by @SchmahmannLab virtuoso neurologist Jeremy Schmahmann @MGHNeurology
ahajournals.org
ahajournals.org
Clinically, thalamic hemorrhage can lead to alteration in level of consciousness and often contralateral hemiplegia due to compression of adjacent internal capsule
Thalamic hemorrhage can lead to 'wrong way eyes' (eyes looking at hemiplegia rather than side of lesion (similar pattern to pontine lesion but atypical for supratentorial)- @prasad_sashank ...why? :)
original paper on this is a classic by C Miller Fisher
jnnp.bmj.com
original paper on this is a classic by C Miller Fisher
jnnp.bmj.com
Small thalamic lacunar stroke can lead to pure sensory lacunar syndrome: contralateral sensory loss of face/arm/leg due to affect on VPL/VPM
There can be a post-stroke thalamic pain syndrome of pain on the contralateral side of the body (Dejerine-Roussy syndrome)
There can be a post-stroke thalamic pain syndrome of pain on the contralateral side of the body (Dejerine-Roussy syndrome)
Acute amnesia can occur due to stroke of anterior nucleus or mediodorsal nucleus
n.neurology.org
n.neurology.org
Bilateral thalamic infarct can be caused by stroke of the artery of Percheron= variant in which both thalami supplied by a single artery-a rare instance in which stroke can present as acute encephalopathy without focal signs (though focal signs may be present if capsule affected)
We like to say "thalamic lesions can do anything" since thalamus is so interconnected w/rest of brain!
Other thalamic pearls @prasad_sashank @MadSattinJ @Tracey1milligan @harvardneuromds ?
This what you were asking for @NMNeurons ?
#EndNeurophobia 🧠❤️
Other thalamic pearls @prasad_sashank @MadSattinJ @Tracey1milligan @harvardneuromds ?
This what you were asking for @NMNeurons ?
#EndNeurophobia 🧠❤️
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