Thalamus and Internal Capsule Flashcards
What sensory information does not travel through the thalamus?
Smell
What is the function of the thalamic nuclei?
Decide which information should reach the cerebral cortex. EXCEPT: reticular nucleus.
Reticular nucleus: projects to other thalamic nuclei and not the cerebral cortex; isolate novel sensory stimuli and enhance activity of one thalamic neuron, while inhibiting random activity around.
What are the inputs to the thalamus?
Specific and regulatory.
Specific input uses glutamate as their neurotransmitter
Regulatory is the majority of the input (cortex, thalamic reticular nucleus, reticular formation). Uses cholinergic, noradrenergic, serotonergic and domaminergic
What are the divisions of the diencephalon?
Epithalamus, dorsal thalamus, subthalamus, hypothalamus
- Epithalamus: pineal gladn, habenular, stria medullaris
- Subthalamus: subthalamic nucleus and zona incerta
What are the divisions of the thalamus?
- Internal medullary lamina - myelinated fibers that divide the thalamus into: anterior, medial and lateral divisions
- Intralaminar nuclei - embedded in the internal medullary lamina
- Thalamic reticular nucleus - partially surrounds thalamus
- Midline nuclei - covers ventricular surfaces of the thalamus
What is the function of the thalamic reticular nucleus?
Only thalamic nucleus thats function is not to decide which information is to reach the cerebral cortex.
Its function is to project to other thalamic nuclei, and using its inhibitory GABAergic neurons, “filter” the information out of the thalamus.
Sheath of neurons that covers the thalamus.
It isolates any novel sensory stimulus from the background and enhance the activity of thalamic neurons while inhibiting random activity around them.
Receives feedback from thalamic nucleus as well as the cortical nuclei and other areas from which the thalamic nuclei project to.
What are the three functional organization groups of the thalamus?
- Specific/relay nuclei
Well defined inputs and projections
Ant, VA, VL, VPM, VPL, medial geniculate, LG, LD - Association nuclei
Reciprocally connected to associated cortex
lateral posterior, pulvinar, dorsomedial - Non-specific nuclei
not the same point to point like specific
intralaminar, reticular of thalamus
What is the function of intralaminar nuclei?
Intralaminar are non-specific thalamic nuclei.
They are responsible for your level of alertness and cognition, getting you ready to perceive information you should prioritize
Anterior nucleus
afferent: mammillary body, hippocampus
efferent: cingulate gyrus
Ventral Anterior (VA)
afferent: basal ganglia (substantia nigra- pars reticulata)
efferent: prefrontal cortex
Ventral Lateral (VL) - anterior
afferent: basal ganglia (globus pallidus, internal)
efferent: supplementary motor area
Ventral Lateral (VL) - posterior
afferent: cerebellar nuclei
efferent: premotor and motor cortex
Ventral Posteromedial (VPM):
afferent: somatic afferents from the head region (CN V)
efferent: somatic sensory cortex
Ventral Posterolateral (VPL):
afferent: somatic afferents from trunk and limbs
- spinothalamic tract
efferent: somatic sensory cortex
Medial Geniculate Body
afferent: brachium of the inferior colliculus
efferent: primary auditory cortex
