Hierarchical Organisation of Visual, Auditory and Motor System.

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  • Created by: em0le
  • Created on: 28-04-18 19:16

Sensory and motor outputs are represented at different levels of abstraction at different levels of corticol networks. What differentiates one level in the hierarchy is the degree that the presented information is abstract. The hierarchical processes can help you go from concrete to abstract. Cogitive through to sensory/motor.

For example, money. There are areas in the brain that care about the monetary value and reward of money but don't care about colour and texture and vice versa. You see patients with lesions in the PFC who are bad at gambling tasks as they are unable to process the abstract property of monetary value.

3 areas that are interconnected to support hierarchical organisation: primary areas, unimodal areas and supramodal areas. The thalamus sends information to the primary cortex which sends information to the unimodal cortex which sends information to the supramodal cortex.

Primary Cortex

Initial level of corticol processing. Low level information like levels and textures. It is the least abstract level. Activity in the PC is specific to one modality. The PC contains maps that are topographic which reflects the physical parameters. For example in the primary visual cortex, neurons responding to different areas of the visual field are spatially organised in the same way the retina recieves the information (upper left is sent to lower right).

- Primary Visual. The retina projects the LGN of the thalamus and then the LGN relays information to the primary visual cortex. It is the first cortical area to process visual information. Orientation selectivity, neurons fire in relation to the orientation of a visual stimulus. Oritentation specific columns

- Primary Auditory. Information is relayed to the medial geniculate nucleas of the thalamus. The MGN projects to the PAC in the superior temporal gyrus of the temporal lobe. cells fire in relation to different auditory frequencies and are cochleotopically mapped, C. neurons are arranged into 3 zones.

- Primary Motor. The PMC sends information out of the spinal cord. It…

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