Lecture 11 Notes
1) Touch doenst have two nerves such as auditory or visual do. Instead it has many somatosensory trunk
Somatosensory trunks are formed by axons of various tactile recptors thant bundle together.
- Also, optic nerves etc go directly to the brian wehre as tactile nerves go through teh spinal cord
to the brian
Touch sensations that result from skin being stimulated are are SPATIALLY represented in area S1
Distorted representation reflects receptor density. Some areas of the bodya re overrepresented in the
sensory homunculs and are dedictae much more processing. .receptors are much more heavily
concentrated in such areas.
Perceived sensation from a physically amputate limb of the body
Parts of the brain are lsitenign in to missing limbs not fullya ware of altered connections so they
attribute activity in these brain areas to stimulation form missing loimbs
Phantom pain is real and could be very intense
Two contact points will elicit different responses if :
-sufficient concentration of receptors at the skin
- small receptive fields
- no convergence of neural processing.
Stereotyped hand movement pattern used to contact objects inroder to perceive their properties
Optimal for obtain precise details about 1 or 2 specific properties
Perception for action; people with anesthesized skin cant grasp even when kinaesthetic perception is
Waht system of touch: geometric properties. Most imp for visual object recognition
Line drawings: easy to see but difficult to perceive haptically. Require haptic integration in space over
time.isntead perceiving material protperties.
Frame of reference is a coordinated systems used to define locations in space.
Centre fo a ref frame: Egocentric ref fram
-whatw e do in everyday life
-we don’t use senses individually
We have multiple pieces of info
Vision is nto good enough. U need to knpow where you head is relative to your body(provided by
Neck info – si non redundant
Vision – 5
Neck + vision = different things 10 +5
One reflects what the head is doing, the other refelecst wehre the knock is seen L1 – FIRST ESTIMATE
Coherence of the world doesnto relaly work when u aer on a boat.
Vision tells u there is no movt btu vestibular ystem says t