PSYCH 2H03 Chapter Notes - Chapter 18: Occipital Lobe, Parvocellular Cell, Iden
12 Nov 2019
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Parallel Processing in the Visual System
Area V1- site on the occipital lobe where axons rom the
LGN rst reach the cortex o Some cells re to horizontals in this
posi on in the visual eld, others to horizontals in that posi on in
the visual eld, others to ver cals, etc.
All specialized areas are ac ve at the same me, the visual
system relies on parallel processing- system in which many di
erent steps are going on simultaneouslyo Advantages: speed,
don’t need to wait un l mo on analysis/colour analysis is
complete before proceedingo Possibility of mutual in uence
among mul ple systems- percep on of shape of object happens
rst, then use result of this processing step as guide for later
analysis
Within the op c nerve, there are 2 types of cells- P cells,
M cells o P cells- provide main input for LGN’s parvocellular
cells and appear to be specialized for spa al analysis and detailed
analysis of form o M cells- provide input for LGN’s
magnocellular cells and are specialized for detec on of mo on and
percep on of depth
The What System- Plays major role in iden ca on of
visual objects
o Some of the ac va on from occipital lobe is passed along to cortex of
temporal
lobeo At same me, ac va on from occipital lobe is also passed along
second pathway,
leading to parietal cortex→The Where System- Performs the func on of
guiding
your ac on, based on your percep on of where object is located
