Sensory Receptors
cells that transduce physical energy into neural signals; from synapses with dendrites
Modality specific
messages carried on separate channels to specific brain areas
Cones
Function in bright light, color vision & acuity more closely racked than rods; 30 million
Rods
Low levels of light, absent from fovea; important for peripheral vision, Not sensitive to color
Achromatopsia
color blindness
Protanopia
red
Deuteranopia
green
Tritanopia
blue
retinofugal Projection
Retina, Optic Nerve, Optic Chiasm,Optic tract, LGN, Superior colliculus, Striate Cortex, Visual Cortex
Magnocellular
large, rods, depth perception, rapid & transient
Parvocellular
Small, cones, color & form, slow & sustained
V1
Orientation
V2
Binocularity
V3
Depth
V4
Color
V5
Motion detection? receptive fields have direction selectivity- neurons fire in response to moving bars of light
Simple cells
respond to specific oriented edges or bars of light and have excitatory/inhibitory regions
Complex
receptive fields; on/off responses to bar of light, no on/off regions
Hypercomplex
receptive fields; on/off responses, has stop-ending
Blob Cells
receptive fields; Wavelength sensitive, monocular, no orientation, direction selectivity
Hypothalamus
biological rhythms
Pretectum
size of pupil
Superior colliculus
orients eyes in response to new stimuli
Ventral stream
what";
Visual Characteristics of the ventral system
face, color, and object recognition
Hearing Characteristics of the ventral system
deals with sound recognition
Dorsal Stream
where
Visual Characteristics of dorsal stream
spatial location
Hearing Characteristics of dorsal stream
processes info like space and motion
Agnosia
failure or deficit in recognizing objects
Apperceptive
sensory perceptual impairment, failure of perception to contact memory; Cause: recovery from "cortical blindness" due to toxins
Ventral ; Bilateral damage to lateral portions of the occipital lobe
WHAT STREAM
Associative
impairment of a store representation of an object in memory ? visual, verbal disconnection.
Simultanagnosia
inability to appreciate meaning of more than one stimulus; may seem blind
Prosopagnosia
inability to identify previously familiar people by facial features
Lesion is bilateral occipitotemporal
...
Capgras syndrome
loved ones have been replaced by imposters
Alexia
Reading problem; severe disturbance of reading comprehension; Brain damage to left angular gyrus
Blindsight
Residual visual abilities within a field defect in the absence of acknowledge awareness