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Neuroanatomy: structure of the nervous system (Cortical columns (Hubel and…

- - - - Cerebral cortex , amygdala, Hippocampus, Basal Ganglia, Septum
    - - Thalamus, Hypothalamus
- - - - Frontal lobe: separated from pariental lobe
        
        by the central sulcus
        
        frontal lobe separated from the motor strip by the precentral sulcus
        
        SFG-superior frontal gyrus
        
        Superior frontal sulcus
        
        Middle frontal gyrus
        
        inferior frontal sulcus
        
        inferior frontal gyrus
        
        MOTOR STRIP # # #
- - - - ie knee jerk reflex arc
      - ie. cells connecting retinal receptors to VC
      - simple spinal cord networks convert sensory info into motor response independent of the brain
  - - - information from several neurons integrated to influence firing of the few
    - - information from few neurons distributed to several other neurons
  - - - SERIAL
        
        brain organised hierarchically where information passed in a serial fashion from one place to another /transformed as it crosses points in the network
      - PARRALLEL
        
        Brain massively parallel structure that info from single source -processed in many locations simultaneously.
- - - - subjects separated dependant on intelligence: Average, High and superior intelligence levels
- - - - hypothesis:
        
        functional organisation of this cortical area . neurons lie in narrow vertical columns, or cylinders -from layer one up to layer 6 -unit of organisation
        
        they are activated by stimulation of the same single class of peripheral receptors , from identical peripheral receptive fields- at latencies wich are not signifigantly dfferent from the cells of the various layersi
        
        form vertical layers as neurons form dense connections with the neurons in above but weaker connections with the neurons on the same layer
        
        110 neurons per column in humans, 270 neurons in primate visual system
        
        1 million columns in the cerebral cortex
  - - - right
        
        from the thalamus
      - left
        
        From the LGN
    - - coloumns of these neurons are organised in stripes(like a tiger) across the cortical surface
      - patterns of optical dominance varies across individuals and species
    - - orientation columns
        
        neurons in the primary visual cortex contain coloumns of neurons which respond specifically to the orientation of the stimulus ie upright, vertical, horizontal
        
        ocular dominance patterns from same brain are superimposed with orientation patterns In the same brain, precise geometric relationships are observed
- - - - primary motor cortex
        
        cortex anterior to central sulcus, posterior to precentral sulcus
        
        BA 4
        
        output to spinal cord input from premotor cortex
        
        activity related to muscles
      - Premotor cortex
        
        cortex anterior to central sulcus, posterior to the precentral sulcus
        
        BA6
        
        output connected to spinal cord and primary motor cortex
        
        activity= relates to action preperation
      - prefrontal cortex
        
        cortex anterior to precentral sulcus
        
        all areas anterior to BA 4 and 6
        
        connected via output to the premotor cortex
        
        activity related to action goals
  - - - old view: primary motor cortex final common pathway for information to influence action
      - New View: recent findnigs show that areas in the premotor cortex also project to the spinal cord
      - example : lesions increasingly impair basic properties of movement moving from PFC to muscles
        
        Lesions increasingly impair higher level functioning moving up from the muscles to the PFC
        
        each level of the frontal lobe network exchanges information with the cerebellum and the Basal Ganglia -monitor and modify activity in each level
- - - - projct directly to the PMC (M1).
      - 2 premotor areas- ventral premotor area (Pmv) and dorsal premotor area (Pmd)
      - 4 premotor areas located in on the medial wall of hemisphere incluing the supplementary motor area (SMA)
        
        and three singulate areas
      - each premotor areas direct projections to the spinal cord
        
        corticospinal axons form premotor areas terminate in the immediate zone of the spinal cord -some terminate in the ventral horn
      - premotor areas like M1 have direct connections with spinal motoneurons - those innervating hand muscles
        
        can evoke movements of the distal and proximal forelimb by stimulating (intercortical) at low currents in the premotor areas
        
        there fore the premotor areas appear to influence control of movement not only in M1 but at the direct level of the spinal cord