Function of Cerebral Cortex

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This answer is oriented to dentistry students.

Physiological anatomy of the cerebral cortex[✎ edit | edit source]

  • 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

Stratification of the cerebral cortex[✎ edit | edit source]

  • 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

A== 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 areaa4
    • Programming of the motor action
    • Collaboration with basal ganglia & cerebellum

The association cortex[✎ edit | edit source]

  • 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

Parieto-occipito-temporal association area[✎ edit | edit source]

  • 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)

The prefrontal association area[✎ edit | edit source]

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

The Limbic Association[✎ edit | edit source]

  • Behavior
  • Emotions
  • Motivation

The specialization of hemispheres[✎ edit | edit source]

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

Planum Temporale[✎ edit | edit source]

  • 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

Links[✎ edit | edit source]

Related articles[✎ edit | edit source]

Sources[✎ edit | edit source]

Prof. Jaroslav Pokorný