Cellular Structure Of Cortex

Front 1

Molecular Layer

Back 1

Superficial layer, rich in axon and dendrite fibers horizontally oriented.
Relatively few cell bodies (neurons)
No inputs or outputs

Front 2

External Granular layer

Back 2

Layer 2; mostly small neurons, a few small pyramidal neurons. input from layer 3 association fibers.

Front 3

External pyramidal layer

Back 3

Layer 3; medium-sized pyramidal cells, which give association and commisural fibers

Front 4

pyramidal cells

Back 4

have apical dendrites and several basal dendrites, give the cell a pyramidal shape.

Front 5

internal granular layer

Back 5

layer 4; composed of stellate neurons, and a few pyramidal neurons. Mostly receives thalamus input, especially in the primary somatosensory cortex.

Front 6

internal pyramidal layer

Back 6

layer 5; medium/large pyramidal cells, giant Betz pyramidal cells. these are so big cuz they project to subcortical areas.

Front 7

multiform layer

Back 7

layer 6; mixed bag; includes stellate, pyramidal neurons. the pyramidals project to thalamus.

Front 8

cell types in the neocortex

Back 8

glial, neurons

Front 9

neuron cell types in neocortex

Back 9

stellate, pyramidal, basket

Front 10

glial cell types

Back 10

microglia, oligodendrocytes, astrocytes

Front 11

Divisions of the cortex

Back 11

Isocortex (neo);
allocortex: paleocortex and archicortex

Front 12

paleocortex

Back 12

olfactory center is an example

Front 13

archicortex

Back 13

hippocampal formation is an example

Front 14

half of brain's volume

Back 14

comprised of the cerebral cortex

Front 15

cortical connection fiber types

Back 15

association, commisural, projection

Front 16

association fibers

Back 16

interconnect cortex within the same hemisphere; primarily in layer 3 to layer 2

Front 17

arcuate fibers

Back 17

short association fibers that connect adjacent gyri

Front 18

longitudinal association fibers

Back 18

long, intercortical connections; like cingulate gyrus, superior/inferior occipitofrontal fasciculi, uncinate fasciculus.

Front 19

commissural fibersq

Back 19

interconnect the two cerebral hemispheres; such as corpus callosum, or anterior/posterior commisure.

Front 20

fugal

Back 20

away

Front 21

corticofugal systems

Back 21

projection fibers from the cerebral cortex layer 5 (large/giant betz pyramidal cells) to subcortical structures. 7 different systems

Front 22

corticothalamic system

Back 22

projection fibers from layer 5 of cortex to thalamus

Front 23

corticosubcortical system

Back 23

a re-entrant circuit; corticostriatal is an example, as it goes from corticostriatopallidothalamocortical loop. basically starts in cortex and ends in cortex.

Front 24

corticorubral

Back 24

projection fiber from layer 5 of cortex 1) red nucleus, then subcortical structure
2)red nucleus to IO to cerebellum

Front 25

corticopontine system

Back 25

a projection system from layer five of cerebrum to the pons then to the cerebellum

Front 26

corticoreticular

Back 26

projection fiber system from layer 5 of the cerebrum to the reticular structures to subcortical structures

Front 27

corticobulbar system

Back 27

corticofugal system from the cortex layer 5 through the internal capsule, descend into the brain stem, emerge on either side of the mesencephalon as the cerebral peduncles, then synapse on lower motor neurons of c.n. 5,7, 9-12.
Motor inputs via superior colliculusand reticular formation for eye movement coordination.

Front 28

corticospinal

Back 28

corticofugal projection system from the 5th layer of the cortex through the internal capsule in three tracts: corticobulbar, lateral corticospinal and anterior corticospinal; the tracts exit the internal capsule on either side of mesencephalon as cerebral peduncles.

Front 29

7 corticofugal systems

Back 29

corticothalamic, corticosubcortical, corticopontine, corticorubral, corticoreticular, corticospinal, corticobulbar. all project from layer 5 except corticothalamic, from layer 6