Function of Cerebral Cortex

This answer is oriented to dentistry students.

Contents 1 Physiological anatomy of the cerebral cortex 2 Stratification of the cerebral cortex 3 Function of specific cortical areas 4 The association cortex 4.1 Parieto-occipito-temporal association area 4.2 The prefrontal association area 4.3 The Limbic Association 5 The specialization of hemispheres 6 Planum Temporale 7 Links 7.1 Related articles 7.2 Sources

edit Physiological anatomy of the cerebral cortex

• Total area of 0.25 m2, giri, sulci, fissures
• Approximately >1010 neurons
• Pyramidal neurons
  • Largest cortical cells
  • Dendrites in different layers
  • Projecting neurons
  • Excitatory (Glutamate, Aspartate NTs)
• Stellate (granule) neurons
  • Local circuit neurons
  • Often send a projecting axon
  • Spiny stellate neurons → Excitatory
  • Smooth stellate neurons → Inhibitory (GABA)
• Fusiform cells
  • Elongated cell
  • Local circuit neurons

edit Stratification of the cerebral cortex

• Most incoming specific sensory signals terminate in layer IV
• Most of output signals leave the cortex from neurons in
  • Layers II & III (corticocortical)
  • Layer V (to brainstem, striatum and the spinal cord)
  • Layer VI (corticothalamic)
• Layers I, II and III perform most of the intracortical association functions
• Cortical columns
  • Neurons along a line perpendicular to the cortical surface have similar response properties and receptive fields

Sensory cortex → IV (mainly)

Primary motor → V, VI (mainly)

Association cortex → in between sensory & primary

edit Function of specific cortical areas

• Primary sensory areas
  • Somatic
  • Visual
  • Auditory
  • For experience of sensation
• Secondary sensory areas
  • Corticocortical input
  • Make sense out of the specific sensory signals (interpreting the shape, texture of a object, stimulating the cutaneous receptors; light intensity or color; combination and sequence of tones)
• Primary motor area
  • Connected with specific muscles
• Secondary motor area
  • Programming of the motor action
  • Collaboration with basal ganglia & cerebellum

edit The association cortex

• Most of the cortex is association cortex
• Cortical areas that receive and analyze signals from multiple regions of the cortex and from some subcortical structures

edit Parieto-occipito-temporal association area

• Polymodal sensory high level analysis and interpretation of signals (visual, auditory and somatosensoric inputs)
• Memory functions
  • Interpretation of sensory information for conscious perception and language
• Functions
  • Spatial coordinates
    • Of the body and surroundings (lesion – loss of the recognition, orientation over one’s own body – contralateral neglect
  • Language comprehension
    • Auditory processing of words (Wernicke’s area) + intelligence
  • Visual processing of written words
    • Lesion → dyslexia, word blindness)
  • Naming of objects
    • Auditory input (names)
    • Visual input (nature of the object)

edit The prefrontal association area

Works in close association with the motor cortex

• Information on the spatial coordinates of the body
• Planning of effective movements
• Neuronal circuitry for word formation

edit The Limbic Association

• Behavior
• Emotions
• Motivation

edit The specialization of hemispheres

Functions that require extensive intracortical connectivity may become lateralized (the capacity of interhemispheric connections is much lower)

• Left hemisphere specialized on the
  • Precise motor movements of hands
  • Word formation and language
  • Logical interpretation of the processed information
  • Rational and analytical thinking
  • Mathematical amplitude
• Right hemisphere is specialized on the
  • Complex and parallel procession of information
  • Nonverbal auditory experience
  • Non verbal visual
  • Non verbal communication
  • Emotional, nonverbal, intuitive thinking
• Evidence of hemispheric asymmetry at birth
  • Physical structure of the brain
  • Hand preference
  • Responses to visual auditory stimuli
• In infancy, different stimuli seem to activate one hemisphere only, or at least one hemisphere more that the other
• Corpus callosum is structurally and functionally incomplete until around two years of age
• The process of hemisphere specialization ends around the age of 12 years.
• Functional specialization of hemispheres (lateralization) coincides with the period of higher plasticity of neuronal circuits

edit Planum Temporale

• A section of the temporal cortex that is larger in the left hemisphere in approximately 65% of the population. This difference in size is apparent at age 3 months in humans
• Children with the biggest ratio of left to right planum temporale performed better in language tests

edit Links

edit Related articles

edit Sources

Prof. Jaroslav Pokorný