PSYC 215 Chapter Notes - Chapter 7: Mach Bands, Peripheral Vision, Receptive Field
Document Summary
Layered with 5 different types of cell, nuclei grouped into 3 separated by plexiform layers: photoreceptor: outer layer responsible for transfusing light energy into neural signals. Rods and cones: outer segment contains a stack of disks packed with sensitive pigments, inner part contains cell nucleus and synaptic terminals. Photon absorption depends on its direction of travel and on its frequency: photon direction: photons arrive in a various direction, depending on where they pass through the pupil. Through the centre: parallel to the long axis. Near the edge: slight angle to the long axis. Nonparallel: not absorbed: frequency: depends on spectral sensitivity of molecule. Three cone photopigment with different spectral sensitivities: frequency near the peak sensitivity > more likely to absorb. Responses: 2/3s of photons result in a response and rest dispute as heat, photoisomerization: mediate any responses. Each molecule has: opsin (protein portion, chromophore (light catching) Mammals use rhodopsin (11-cis retinal) as chromophore.
