Cerebral Cortex

unique characteristics of the human brain

reasoning, memory, language, speech, calculations, praxis, object recognition

functions are

asymmetrically organized in the cerebral hemispheres

cerebral dominance i.e specialization of one hemisphere in specific functions

relates to unique cytoarchitectural organization

cerebral cortex layers

I= molecular layer

II= external granular layer

III= external pyramidal layer

IV= internal granular layer

V= internal pyramidal layer

VI= multiform layer

the human brain contains around

one hundred billion neurons

cell types

-pyramidal cells

-fusiform cells

-stellate cells

-horizontal cells of Cajal-Retzius

-cells of Martinotti

cerebral cortex contains

-motor cortex

-primary motor cortex

-secondary motor cortex

the central nervous system is composed of

gray and white matter

the gray matter consists mostly of the

neuronal bodies

the white matter consists of the

axons of the neurons

cytoarchitecture layers

different layers of the brain(tissue)

molecular layer

most superficial layer, has very few neurons

external granular layer

contains grain like cells that receive input from nearby cortical areas, distributes info to other parts of the cortex

external pyramidal layer

section that contains pyramidal neurons, which have axons that project to other cortical areas. A major source of cortical communication(motor info)

internal granular layer

important for sensory input/information

internal pyramidal layer

It has some of the largest pyramidal neurons in the brain. send long projections to different subcortical areas, the brainstem, and all the way down the spinal cord. major output for pyrmadial system

multiform layer

a mixture of cells(motor and sensory). gives feedback signals to the thalamus. regulates and fine tunes sensory information

morphology is the

base for functional outputpyr

pyramidal cells

large, triangular shape, dendrites at the end. serve as primary output neurons of the brain. essential for motor control, cognition, communication between different regions of the brain

cortex is not a

uniform sheet of the same neurons

fusiform cells

spindle shape, located in deep cortical areas, send information back to the thalamus. provide feedback information. helps to regulate sensory input

stellate cells

star shape, found in granular layers and serve as interneurons. receive incoming sensory information to the thalamus.

Cajal-Retzius cells

cells found mostly in surface of the cortex(layer 1). play a role in the development of the human brain. as the brain develops there aren’t as many 

cells of Martinotti

interneurons, found all throughout cortical areas and upper area of level 1. provide inhibitory control 

plexiform layer

located right under the pia mater

motor cortex

The region of the cortex that is responsible for planning, controlling, and executing voluntary motor movement. a broad network of cells