Cortex

• Cells of the cortex

  I. Molecular layer

  II. Outer granular layer

  III. Outer pyramidal layer

  IV. Inner granular layer

  V. Inner pyramidal layer

  VI. Multiform layer
• Corticothalamic projections

  • Corticothalamic connections regulate thalamic activity and can exert a flexible control of thalamocortical inputs
  • During active thinking, electroencephalography (EEG) reveals a strong appearance of gamma range oscillation from around 20–50 Hz
• Functional areas of the cortex

  • Cerebral cortex is involved in conscious awareness, thought, memory, sensation and movement
  • In addition to primary areas there are association areas
• Cortical Maps


  • Sensory areas in the brain are arranged in a topographic fashion
  • In primary sensory and primary motor cortex there is somatotopic organization
• Cortical sensory processing streams

  1. Primary sensory areas send output in parallel streams dorsally and ventrally to association cortices (parietal-spatial info or temporal-emotional/object recognition info)

  2. Then sensory info then travels to frontal cortex for motor and executive action
• Pattern of higher sensory processing

  Primary → unimodal → multimodal
• Focal cerebral lesions can cause syndromes like hemispatial neglect, visual object agnosia, expressive aphasia, and receptive aphasia
• Frontal cortex

  • Speech formation (Broca's area)
  • Gaze (frontal eye fields)
  • Working memory (dorsolateral prefrontal cortex)
  • Risk processing (ventromedial prefrontal cortex)
• Cortical pathology: Brain bleeds

  • Subdural haemorrhage
  • Epidural haemorrhage
• Cortex pathology: Alzheimer's


  • enlarged ventricles
  • pronounced sulci
  • Loss of white matter tracts (shrunken)
• The cortex has areas devoted to vision, hearing, motor action, objection recognition, speech, smell, etc.
• Cortical maps organise sensory information by function (ie topography)
• Sensory information goes from their primary sensory cortices to unimodal sensory areas and then multimodal cortical areas (via dorsal and ventral streams) before reaching at the frontal cortex
• Hemispatial neglect, aphasia and agnosia can be a consequence of focal cerebral lesion
• Subdural haemorrhage is blood between the brain the dura. An epidural haemorrhage is blood between the brain the dura skull and the dura mater
• Context: Modulation


  • Pathways can be modulated by other areas of the brain
  • Pathways can be inhibited or excited by other areas
  • Neurotransmitter is a signalling molecule secreted by a neuron to affect another cell across a synapse
  • Pathways often send-off outputs to major nuclei for coordinated functioning
• Cerebellum

  • Is involved in: Maintenance of equilibrium, Posture and muscle tone, Coordination of movement, Hearing, Facial sensations
  • Cerebellum has been traditionally thought of as a motor structure, however, a lot of evidence of the last 30 years has shown involvement in other functions
  • Cerebellar Cognitive Affective Syndrome has deficits in executive function, spatial cognition, language, and affect
• Cerebellum gross anatomy

  • Anterior Lobe
  • Posterior Lobe
  • Superior cerebellar peduncle
  • Middle cerebellar peduncle
  • Inferior cerebellar peduncle
  • Nodule
  • Flocculus
  • Posterolateral fissure
• Internal cerebellum nuclei


  • Dentate- planning, initiation and control of voluntary movements (ventral: non-motor, dorsal: motor)
  • Emboliform- part of spinocerebellum tract, that regulates the precision of limb movements
  • Globose- part of descending motor tracts involved in motor control
  • Fastigial- vestibular and saccadic eye movements
• Cerebellum cellular layers

  • Outer: molecular layer
  • Intermediate: Purkinje cell layer
  • Inner: granular layer
• Cerebellum pathways

  1. Cerebrocerebellar: Function: muscular coordination and control, Connections: pons, middle cerebellar peduncles, dentate nucleus

  2. Spinocerebellar: Function: muscle tone and posture, Connections: superior and inferior cerebellar peduncles, red nucleus, globose, emboliform, fastigial

  3. Vestibulocerebellar: Function: balance, Connections: vestibular, red nucleus and reticular nucleus of brainstem, fastigial