Thalamus/Cortex 1: Anatomy Flashcards
Is the thalamus mostly white matter, grey matter, or both?
It’s pretty much all grey matter.
What are 3 types of circuits in the thalamus?
Relay, association, and non-specific.
What’s the name of the wall of white matter that separates the thalamus into medial and lateral parts?
the internal medullary lamina (IML)
What are encircled by the walls of the intermedullary lamina where it splits anteriorly? What are their most important function?
Anterior nuclei - maintain wakefullness.
Where is the nucleus reticularis located in the thalamus?
It covers the whole thing like a sheet of paper.
What part of the thalamus receives sensory (touch, proprioception) info from the head, mostly CN V?
The ventral posteromedial (VPM) nucleus.
*corrected from… something incorrect and not real
Where does auditory info go in the thalamus?
The medial geniculate body.
Where does visual info go in the thalamus?
The lateral geniculate body.
Where does limbic information go in the thalamus?
The anterior nuclei (part of the Papez circuit)… which relays it to the cingulate gyrus
What sort of signaling happens between the thalamus and cerebral cortex? Neurotransmitter used?
Reciprocal excitatory signaling, using glutamate.
How does the reticular nucleus interact with the cortex and thalamocortical (TCs) relay neurons? Neurotransmitter used?
Cortex and TCs relay neurons send excitatory signals to the reticular nucleus, using glutamate.
Reticular nucleus send inhibitory signals only to the TCs, using GABA.
Are the thalamocortical cells connected to eachother?
No.
How many layers are in the cerebral cortex? Is layer thickness consistent across all areas of the cortex?
Six (though sometimes debated). No, the thickness varies by region.
The histology of the cortex ranges from granular to agranular. Are motor areas more granular or agranular? Sensory?
Granular: Mainly sensory
Agranular: Mainly motor
What is the Brodman map based on?
Histological differences between regions of the cortex.
Do all neurons in a column of the cortex share functionality and respond to the same stimuli?
Yes.
What are the two types of excitatory cells found in the cortex?
Pyramidal cells and granular cells.
How can you tell an excitatory from and inhibitory neuron just by histology?
Excitatory cells have spines on their dendrites, inhibitory cells don’t.
What’s the major feature you can use to identify a pyramidal cell in histology?
The apical dendrite. (the triangular cell body can sometimes be hard to see)
In what cortical layer are granular cells primarily found?
Layer 4.
In what layer does information from the thalamus arrive in the cortex?
Into layer 4.
What’s the basic circuit-unit in the cortex?
Excitatory signal comes into layer, stimulates inhibitory cell and second excitatory cell. Inhibitory cell inhibits the second excitatory cell. Second excitatory cell send an excitatory signal to the next layer.
What’s the order of cell layers through which information travels in the cortex?
Into 4, up to layers 2/3, down to layers 5/6, and out.
Basically what’s different about the modern model of thalamus / cortex information flow vs. the traditional “serial” flow model?
Cortex (both motor and sensory) provide feedback to the thalamus…
