Thalamus Flashcards
parts of the diencephalon
- thalamus
- subthalamus
- hypothalamus
- epithalamus
internal capsule fibers
- brings output of cortex to subcortical sites (to LMNs)
- carries all projections from thalamus to cortex via posterior limb (except for optic)
all sensory systems but ________ system project to the thalamus and synapse there
all sensory systems but OLFACTORY system project to the thalamus and synapse there
thalamus receives motor input from ________ and _________, which is then projected to areas of primary and associated motor cortex
thalamus receives motor input from the CEREBELLUM and BASAL GANGLIA, which is then projected to areas of primary and associated motor cortex
thalamus receives input from:
- all sensory but olfactory
- cerebellum
- basal ganglia
- limbic system
- parietal, occipital, temporal cortex
subdivisions of the thalamus
- anterior
- medial
- lateral
- posterior
thalamic nuclei
- medial geniculate body
- lateral geniculate body
- VPL (ventroposterolateral)
- VPM (ventroposteromedial)
- VA (ventral anterior)
- VL (ventrolateral)
- anterior
- dorsomedial
- pulvinar
medial geniculate body
inf. colliculus –> medial geniculate –> Heschl’s gyrus (A1)
lateral geniculate body
optic tract –> lateral geniculate –> visual cortex (V1)
VPL
somatosensory pathways (STT, dorsal column) -sensory info from BODY
STT/DC –> VPL –> sensory cortex
VPM
somatosensory pathways (trigeminothalamic tract) -sensory info from FACE
trigemial (all) –> VPM –> lower end of sensory cortex
somatosensory nuclei of thalamus
- VPL
- VPM
motor nuclei of thalamus
- VA
- VL
VA
- motor system
- basal ganglia
globus pallidus –> VA –> motor, motor association
VL
- motor system
- cerebellum
deep nuclei –> VL –> motor, motor association
limbic system
-memory, emotion
papez circuit
-limbic system
mamillary bodies –> anterior –> cingulate gyrus hippocampus –> mamillary bodies
anterior nucleus
- limbic system
- papez circuit
mamillary bodies –> anterior –> cingulate gyrus hippocampus –> mamillary bodies
association nuclei
- dorsomedial
- pulvinar
project to association cortex
DM
-dorsomedial
amygdala –> DM –> frontal
Pulvinar
T/P/O –> Pulvinar –> T/P/O cortices
function of the thalamus
modulation of signals before they enter the cortex
–allows for selective attention
pure sensory stroke of thalamus
- lacunae in VPL, VPM
- –loss of all sensation in body/face
- infarct due to small vessel disease
- associated with hypertension, DM
typified by:
- microatheroma
- lipohyalinosis
microatheroma
- deposit or degenerative accumulation of lipid-containing plaques on the innermost layer of the wall of an artery
- typical of a pure sensory stroke of thalamus
lipohyalinosis
- degenerative changes in small blood vessels
- accumulation of glassy/waxy looking lipid in vessel wall
-typical of pure sensory stroke of thalamus
thalamic hemorrhage
- spontaneous intracerebral hemorrhage
- associated with hypertension
- involvement of adjacent internal capsule (dominates, adds hemiparesis)
- also sensory involvement
common symptoms of thalamic hemorrhage
- numbness, sensory deficits on CONTRAlateral side
- sometimes developing into thalamic pain
- hemiparesis
