What is wrong with the idea that human visual perception is achieved Essay

What is wrong with the idea that human visual perception is achieved by a single area of the brain that simply reflects the cisual information coming from the e - Essay Example the optic nerves which consist of about a million nerve fibers and contain axons arising from the inner, ganglion-cell layer of the retina (Guyton & Hall, 1996; Waxman, 2000). The arrangement at the optic chiasm allows the left hemisphere to receive visual information about the contralateral half of the visual world and vice-versa (Guyton & Hall, 1996; Waxman, 2000). Moreover, the fibers of each optic tract synapse in the dorsal lateral geniculate nucleus and from here, the geniculocalcarine fibers pass by way of the optic radiation to the primary visual cortex in the calcarine area of the occipital lobe (Guyton & Hall, 1996). The most important cortical region for visual processing is Area V1 in the occipital lobe because it is the first stop in the cortex and almost all of the signals that the other cortical regions get must pass through it which is why Area V1 is often referred to as the primary visual cortex or striate cortex (Coren, Ward, & Enns, 1999). Hubel and Wiesel found cells in the cortex with receptive fields that have excitatory and inhibitory areas and are arranged side-by-side rather than in a center-surround configuration (Goldstein, 2007). Simple cortical cells are cells which have these side-by-side receptive fields mentioned previously and these cells respond best to bars of a particular orientation (Goldstein, 2007). Other kinds of cells in Area V1 are even tuned to more complicated pattern properties of the stimulus such as complex cortical cells which respond best to movement of a correctly oriented bar across the receptive field, and at an even more complicated level of analysis than the complex cells are hypercomplex or end-stopped cortical cells that respond not only to the orientation and direction of movement of the stimulus but also to the length, width, or other features of shapes, such as the presence of corners (Coren, Ward, & Enns, 1999; Goldstein, 2007). Simple, complex, and hypercomplex cells are refer red to as feature