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Central Visual System (Central projections of retinal ganglion cells…

- - - - Layer 4C: the primary recipient of lateral geniculate nucleus afferents
        
        Spiny stellate cells: cells with dendrites extending from the cell body which are able to make connection within the cortex
        
        Pyramidal cells: spines and thick, apical dendrite - layers III, IVB, V, VI
        
        ONLY cells that send axons out of V1 - glutamatergic
  - - - Layer II, III, IVB cells project to other cortical areas, Layer V to superior colliculus and pons, and Layer VI back to the LGN
  - - - Outside of IVC, different receptive field conditions are found
        
        Most neurons above layer IVC are binocular, i.e. respond to signals/light from either of the eyes
        
        Layer II and III neurons are also binocular, but respond more to the order/actions of layer IV neurons
- - - - Much of V1, part of this cortex is on the medial surface of the brain
  - - - Layers 1 and 2: Magnocellular LGN Layers (input from M-type)
      - Layers 3-6: Parvocellular LGN Layers (input from P-type)
      - Koniocellular LGN layers: input from nonM-nonP
        
        Each koniocellular layer receives input from the same eye as the overlying M or P layer
      - Info from these three types of RGC's from both eyes remains segregated, but streams of info are processed in parallel
      - Receptive Fields of LGN Cells - nearly identical to the ganglion cells that feed them
        
        Magnocellular LGN Neurons: large, center-surround RFs with transient bursts, insensitive to differences in wavelengths
        
        Parvocellular LGN Neurons: small, center-surround RFs with sustained responces, color opponency
        
        Konicellular LGN cells: center-surround RFs which distinguish light/dark or color opponency
- - - - Simple cell receptive fields: simple cells in VI are binocular, orientation-selective, with an elongated ON or OFF area flanked with antagonistic surround
      - Complex cell receptive fields: complex cells in V1 give ON and OFF responses to stimuli throughout the RF not as simple as the center-surround cells