chapter 5 lecture Flashcards
transduction
the process by which sensory stimuli are converted to neural signals the brain can interpret
transduction in electromagnetic
light is converted from electromagnetic energy to energy in the form of action potential (neural impulses)
what is a subjective process, sensation or perception
preception
sensation
the stimulation of sense organs
involves the absorption of energy (light sound waves) by sensory organs (eyes and ears)
perception
the selection, organization and interpretation of sensory information
- involves the translation of sensory information into something meaningful
what physical property matches with the hue of a colour
wavelength/frequency
what related preception of colour matches with amplitude
brightness
what related perception matches with purity
saturation
timbre
purity of sound. A pure tone that has only one frequency and one amplitude
what sets apart sound of a piano from sound of flute
what physical property of sound relates to the perception of pitch
wavelength/ frequency
what related perception does amplitude match with
loudness
what physical property matches with timbre
purity
blind spot
the nerves that run from the retina to the brain converge at a spot this spot has no receptor cells
- any image that falls on this spot cannot be seen
- each eye has a blind spot, but you are not aware of the spot because each eye compensates for the blind spot of the other
the retina contains millions of ____ cells. they are where in the retina, what does this mean
receptor
innermost layer
means only 10% of light arriving at the cornea reaches the receptor
receptor cells are sensitive to
light or photoreceptors
do humans have more rods or cones, how many
more rods
rods= 100-125 million
cones =5 to 6.4 million
What are the two types of receptor cells. what classifies them
rods and cones
- shape classifies them
what is the fovea
tiny spot in the center of retina that contains only cones
the periphery of the retina is outnumbered by
rods
cones are responsible for
colour vision
daylight vision
visual acuity
rods are responsible for
peripheral (area right outside of the fovea) vision
night vision
how many light absorbing pigments do rods and cones have
rods - have the same
cones- three different (which any one cone has one of )
four in total
where is visual information processed
retina and brain
in the retina, where is visual information processed
in the receptive field of a ganglion cell
processes- perception of light/dark contrasts
in the brain where it visual information isual information processed
the visual cortex
- the thalamus, occipital lobe, parietal lobe, and temporal lobe
processes- perception of brightness, orientation, form (face body parts), colour motion depth)
each ganglion cell has its ______ _______ when stimulated what is it responsible for seeing
receptive field- light/dark contrast
center-surround antagonism is a receptor field property on a ____ cell
ganglion
The rate of firing a nerve impulse increases when
light falls in the center of a receptive field
Feature of the receptive field
Center excitatory; surrounding inhibitory
The rate of firing a nerve impulse decreases when
light falls on the surrounding area.
In this figure, shading indicates the area stimulated with light. The largest response
occurs when the entire center (an excitatory area) is illuminated.
thalamus processes
perception of brightness
primary visual cortex in the occipital lobe controls the process of
perception of orientation
inferior temporal lobe processes
perception of form and colour
parietal lobe processes
perception of motion and depth
explain the perception of orientation through the cat experiment
A cat was shown a line in various orientation.
* A microelectrode was placed in the cat’s primary visual cortex.
Action potentials from individual neurons were recorded by an
oscilloscope.
* Findings: A vertical line elicited rapid firing rate; a horizontal line
elicited no response (firing rate was at baseline measure); a tilted line
elicited moderate firing rate
* Conclusion: Neurons are highly specialized; they respond to very
specific stimuli.
After visual
information is
processed in the
primary visual cortex,
it is sent to two other
cortical areas for
further processing. what are the two pathways
dorsal stream
and the ventral stream
ventral stream leads to the
temporal lobe
the ventral stream processes the details of
(including color & form) of “what” objects are
out there—the “what” pathway
when the ventral stream is damaged the person suffered from
agnosia
explain the different types of agnosia
visual-form agnosia (inability to
recognize visual forms or familiar objects), color agnosia (inability to
recognize colors), face agnosia (inability to recognize faces
D.F., a 35-year-old-woman, suffered extensive lesion in her occipital &
temporal lobes as a result of carbon monoxide poisoning. Her ventral
pathway was damaged. She experienced visual-form agnosia.
D.F. was unable to copy objects with simple
contours.
* Interestingly, she could draw them from
memory. But when doing so, she did not
recognize what she was drawing.
* Although she could see grids of lines on a
screen, she could not tell whether they
were vertical or horizontal.
* She could not identify objects based on
their forms and shapes
* D.F. did not have an integrated visual
experience.
* Her visual world had no forms and shapes.
the dorsal stream leads to
the parietal lobe
the dorsal stream processes
“where” the objects are and “how” to interact with these
objects—the “where” or “how” pathway
the dorsal stream is a _____ ___ _______ pathway
vision for action pathway