PERCEPTUAL SYSTEMS AND MOTOR CONTROL

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PERCEPTUAL SYSTEMS AND MOTOR CONTROL
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Vision and the Eye
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The Retina
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Rods and Cones

• Cones
• Photopic vision
• High acuity good light colour
• Low convergence
• Fovea

• Rods
• Scotopic vision
• Low acuity low light achromatic
• High convergence
• 20º from fovea

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Receptive Fields

• area in which it is possible for a stimulus to
  influence the firing of the neuron
• increases or decreases in firing

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Receptive Fields
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Lateral Inhibition and Contrast Enhancement
Communication within the Retina

• Edges provide information
• Mach bands
• Contrast enhancement

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Mach Bands
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Lateral Inhibition
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From the Eye to the Brain
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Pathways from LGN
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Visual Cortex

• A number of cells respond to visual input
• Simple cells
• Complex cells

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Simple Cells
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Complex Cells
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Audition

• From the ear to the brain
• Auditory signals converted to electrical impulses
• Information passed down auditory nerve
• Auditory cortex

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Audition
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Olfaction

• From the nose to the brain
• Odours are detected and converted into neural
  impulses
• Two routes to the olfactory cortex
• Does not have to go via thalamus

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Olfaction
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Somatosensation

• Tactile information relayed to the brain via
  several pathways
• Anterior lateral pathway
• Dorsal column pathway

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Somatosensation
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Gustation

• From the mouth to the brain
• Salt
• Sour
• Sweet
• Bitter

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The Vestibular System

• Locates the position and change of position of
  the head
• By the ear

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The Vestibular System
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Motor Control

• Respond to incoming signals
• Reflexes
• Motor programmes

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Motor Control and the Brain

• Pyramidal motor system
• Motor cortices
• Supplementary motor area
• Extrapyramidal motor system
• Communicates with
• The basal ganglia
• Cerebellum