Anatomy of the Cerebral Cortex: Key Points

Overview of the Central Nervous System

• Central nervous system includes the spinal cord and the brain.
• Brain components:
  • Cerebrum
  • Diencephalon
  • Cerebellum
  • Brainstem

Cerebrum Structure

• Consists of two symmetrical halves: cerebral hemispheres and basal ganglia (or basal nuclei).
• Each hemisphere is divided into:
  • Frontal lobe
  • Parietal lobe
  • Temporal lobe
  • Occipital lobe
  • Insula (fifth lobe)

Gray and White Matter

• Cerebral Cortex
  • Outermost area of cerebral hemispheres
  • Composed of gray matter with billions of nuclei or neuronal cell bodies
• Neurons
  • Consist of a cell body, dendrites, axon, and synaptic terminal
  • Facilitate information processing and communication
• White Matter
  • Located beneath gray matter
  • Composed of myelinated axons
  • Largest tract: Corpus callosum

Basal Ganglia

• Includes:
  • Caudate and putamen
  • Globus pallidus
  • Subthalamic nucleus
  • Substantia nigra
• Terminology:
  • Striatum: Caudate and putamen
  • Lentiform nuclei: Putamen and globus pallidus
  • Corpus striatum: Caudate, putamen, and globus pallidus

Brain Anatomy and Function

• Gyri and Sulci
  • Gyri: Folds in the cerebral cortex
  • Sulci: Shallow grooves
  • Fissures: Deep grooves
• Purpose
  • Increase surface area for more nuclei, enhancing processing and higher cortical function
  • Help separate brain into lobes

Brodmann's Areas

• Histologically similar regions of the cerebral cortex
• Approx. 180 areas identified

Major Fissures and Sulci

• Longitudinal Fissure: Divides brain into left and right hemispheres
• Central Sulcus/Fissure of Rolando: Separates frontal and parietal lobes
• Lateral Fissure/Sylvian Fissure: Separates frontal and parietal lobes from the temporal lobe
• Parieto-Occipital Fissure: Divides parietal and occipital lobes

Frontal Lobe Details

• Central Sulcus and Precentral Sulcus: Form borders of the precentral gyrus
• Superior, Middle, and Inferior Frontal Gyri
• Brodmann's Areas:
  • 4: Primary motor cortex
  • 6: Premotor cortex
  • 8: Frontal eye field
  • 44/45: Broca’s area

Primary Motor Cortex

• Responsible for voluntary movements
• Somatotopy: Organization of body regions in the cortex
• Motor Homunculus: Visual representation of cortical body part control

Functional Areas

• Prefrontal Cortex: Executive functions, including reasoning and planning
• Broca’s Area: Speech production

Significance of Cortical Areas

• Neurons dedicated to specific movements based on importance, not muscle size.