2 & 3 FOREBRAIN/ CEREBRAL CORTEX/ THALAMUS/ INTERNAL CAPSULE Flashcards
Describe the homotypical layers of the cortex and give examples of cortex areas that are arranged in this way
Layer I - molecular Layer II - External granular Layer III - External pyramidal Layer IV - Internal granular Layer V - Internal pyramidal Layer VI - Multiform. The association cortex's, prefrontal, parietal, temporal
Describe the layers of the motor cortex
Layer I - molecular Layer II - no cells Layer III - Big pyramidal cells Layer IV - no cells Layer V - giant pyramidal cells Layer VI - Some pyramidal cells
Describe the layers of the somatosensory cortex
Layer I - molecular Layer II - granular cells Layer III - no cells Layer IV - lots of granular cells Layer V and VI - no cells.
What divides the allo cortex from the neocortex
The rhinal or collateral sulcus
Describe pyramidal cells
Large cells, triangular base. Long apical and basal dendrites. Also known as efferent or Golgi Type I cells. Involved in output info to other regions e.g. thalamus, basal ganglia, down spine
Describe granular cells
Round cells with short axons. Also known as local circuit neurons of Golgi type II. They talk to adjacent neurons and process sensory information. Are interneurons
How many layers does the allo cortex have
3
How many layers does the neocortex have
6
In what cortex layer are commissural and association fibres found
Layer III, external granular
What layer are projection fibres found and where do they go to
Layer V, internal granular. Project to subcortical structures
What layer are specific afferent fibres found and describe
Layer IV, internal granular. E.g. from thalamic relay nuclei
Describe the function of the thalamus
An area of the brain that determines what sensory signals go to and from the cortex. The thalamus is organised into regions that have specific jobs, e.g. all cortical areas are represented in the thalamus.
There are afferent and efferent fibres in the thalamus so the thalamus can modulate sensory input to the cortex (i.e. blocking out some sensory inout to cortex as well as delivering it)
What are the relevant (to this paper) areas of the thalamus
Ventral Anterior nucleus, ventral lateral nucleus, ventral posterior nucleus, lateral geniculate body and medial geniculate body.
What is the medial geniculate body responsible for
Auditory sensory pathways.
What is the lateral geniculate body responsible for
Visual sensory pathways
What are the ventral anterior and ventral lateral nucleus responsible for
Pathways from the basal ganglia and cerebellum and primary motor cortex and sensory cortex influencing movement
What is the ventral posterior nucleus responsible for
Relates sensory information to and from primary sensory cortex
What is the function of the internal capsule
Only way in and out of the cortex!
What are the divisions of the internal capsule
Anterior limb, genu, posterior limb, retrolenticular, sublenticular.
What part of the internal capsule passes visual fibres
The retrolenticular
What part of the internal capsule passes auditory fibres
The sublenticular
What fibres pass through the genu
Motor for face- corticobulbar fibres
What fibres pass through the anterior limb
Basal ganglia tracts
What fibres pass through the posterior limb
Corticospinal tract, some visual, auditory and sensory pathways from the thalamus
