Search results
Results From The WOW.Com Content Network
The area of the visual cortex that receives the sensory input from the lateral geniculate nucleus is the primary visual cortex, also known as visual area 1 , Brodmann area 17, or the striate cortex. The extrastriate areas consist of visual areas 2, 3, 4, and 5 (also known as V2, V3, V4, and V5, or Brodmann area 18 and all Brodmann area 19 ).
In 1958, David Hubel and Torsten Wiesel discovered cells in the visual cortex that had orientation selectivity. This was found through an experiment by giving a cat specific visual stimuli and measuring the corresponding excitation of the neurons in striate cortex (V1). The experimental set up was of a slide projector, a cat, electrodes, and an ...
These areas include V2, V3, V4 and area V5/MT. (The exact connectivity depends on the species of the animal.) These secondary visual areas (collectively termed the extrastriate visual cortex) process a wide variety of visual primitives. Neurons in V1 and V2 respond selectively to bars of specific orientations, or combinations of bars.
There are between 14 and 16 billion neurons in the cortex. [2] These cortical neurons are organized radially in cortical columns, and minicolumns, in the horizontally organized layers of the cortex. [9] [10] The neocortex is separable into different regions of cortex known in the plural as cortices, and include the motor cortex and visual cortex.
Axons from layer 6 of visual cortex send information back to the LGN. Studies involving blindsight have suggested that projections from the LGN travel not only to the primary visual cortex but also to higher cortical areas V2 and V3. Patients with blindsight are phenomenally blind in certain areas of the visual field corresponding to a ...
Neurons communicate with other cells via synapses, which are specialized connections that commonly use minute amounts of chemical neurotransmitters to pass the electric signal from the presynaptic neuron to the target cell through the synaptic gap. Neurons are the main components of nervous tissue in all animals except sponges and placozoans.
Each visual area contains a full representation of visual space. That is, it contains neurons whose receptive fields together represent the entire visual field. Visual information enters the ventral stream through the primary visual cortex and travels through the rest of the areas in sequence.
Ocular dominance columns are stripes of neurons in the visual cortex of certain mammals (including humans [1]) that respond preferentially to input from one eye or the other. [2] The columns span multiple cortical layers, and are laid out in a striped pattern across the surface of the striate cortex (V1).