Layers of the Cerebral cortex Flashcards
Enumerate all the layers of the cerebral cortex
Molecular layer (plexiform layer)
External Granular layer
External Pyramidal Layer
Internal Granular layer
Internal Pyramidal layer (ganglionic layer)
Multiform layer (layer of polymorphic cells)
Most superficial which lies directly under the pia mater
Molecular layer/ plexiform layer
Consist of dense network of tangentially oriented nerve fibers.
molecular layer
Large number of synapses between different neurons that occur
molecular layer
Large number of small pyramidal cells and stellate cells
External Granular Layer
existence of small cells in the
layer that gives a granular appearance
granular
Pyramidal = larger pyramidal cells found here
External pyramidal layer
Main input of cortical station
Internal Granular Layer
Most of the stimuli from periphery arrive here
internal granular layer
Closely packed stellate cells (External band of Baillarger) and smaller portion of
pyramidal cells
Internal Granular Layer
Betz cells and medium-sized pyramidal cells
(3% of projection of cortiscopinal tract)
Stellate cells and Cells of Martinotti
Motor activity
Scattered among the pyramidal cells are stellate cells and cells of Martinotti. In addition, a large number of horizontally arranged fibers form the inner band of Baillarger
Internal Pyramidal Layer (Ganglionic Layer)
Although the majority of the cells are fusiform, many of the cells are modified pyramidal cells, whose cell bodies are triangular or ovoid. The cells of Martinotti also are visible bin this layer
Multiform layer (layer of polymorphic cells)
Composed of closely packed stellate cells with a high concentration of horizontally arranged fibers known collectively as the external band of Baillarger
Internal granular layer
It is composed of pyramidal cells whose cell body size increases from the superficial to the deeper borders of the layer.
External pyramidal layer
large pyramidal cells
betz cells
Responsible for the projection
fibers of the corticospinal
(pyramidal) tract
Betz cells
Responsible for the rapid
skilled voluntary
movements of the limbs
Controls the prime mover
muscles
corticospinal (pyramidal) tract
layer that contains the betz cells
ganglionic/ internal pyramidal layer
Decreased/absence of
Betz cells causes
motor neuron disease (primary lateral sclerosis)
primary lateral sclerosis affected tracts
Corticobulbar, Corticospinal
tract
most important cells in
the cerebrum
betz cells
most important
cells in the cerebellum
purkinje cells
Most common type of neuron
Apex pointing outwards toward the pia surface of the
brain
pyramidal cells
Extend orthogonally to their cells layer with dendrites
extending either into deeper and more superficial
layers.
fusiform cells
Also known as granule layer
Rounded with short dendrites rotating
circumferentially out of the body
Predominantly found in layers 2, 4, 6
stellate cells
stellate cells predominantly found in
layers 2, 4, 6
Small cells w/ limited number of short dendrites and
axons which extends superficially
In first layer, afferent fibers originating in thalamus
and its association with the commissural fibers are
also present.
cells of martinnotti
Least common cell type, only found in layer 1
cajal retzius
how many layers in cerebellum and cerebrum
cerebellum - 3
cerebrum - 6
