Sensation and Perception Flashcards
Sensation
intake of sensory information; conversion of physical, auditory, etc information into electrical signals for nervous system
Perception
processing of sensory information to make sense of its significance
Sensory Receptors
neurons that respond to stimuli and trigger electrical stimuli
Ganglia
collections of neuron cell bodies found outside the central nervous system
Name 7 sensory receptors
Photoreceptors - respond to electromagnetic waves in the visible spectrum
Hair cells - respond to movement of fluid in the inner ear structures
Nocireceptors - respond to painful or noxious stimuli
Thermoreceptors - respond to changes in temperature
Osmoreceptors - respond to the osmolarity of the blood
Olfactory receptors - respond to volatile compounds
Taste receptors - respond to dissolved compounds
Threshold
the minimum amount of stimulus that renders a difference in perception
Absolute Threshold
minimum of stimulus energy that is needed to activate a sensory system
Subliminal Perception
Perception of a stimulus below a given threshold. The stimulus arrives at the CNS but does not get to higher order brain regions that control attention and consciousness
Discrimination testing
having a participants shown two stimulus and record when they can tell a difference between the two in order record human perceptive ability
Difference threshold
aka “just-noticeable difference (jnd)” minimum difference in magnitude between two stimuli before one can perceive this difference
Weber’s Law
there is a constant ratio between the change in stimulus magnitude needed to produce a jnd and the magnitude of the original stimulus
Signal Detection Theory
perception of stimuli is affected by nonsensory factors, such as experiences, motives and expectations, evaluates changes in perception based on internal and external factors
Response bias
the tendency of subjects to systematically respond to a stimulus in a particular way due to nonsensory factors
Adaptation
a change in our detection of a stimulus over time
What is the pathway for stimulus to reach conscious perception?
Sensory receptor —> afferent neuron —> sensory ganglion —> spinal cord —> brain (projection areas)
What is the sclera?
the white of the eye that covers most the exposed portion of the eye except the cornea, provides structural support
What supplies the eye with blood?
the choroidal vessels - complex intermingling of blood vessels between sclera and retina and retinal vessels
What is the retina?
innermost layer of the eye which contains the actual photoreceptors that transduce light into electrical information the brain can process
What is the cornea?
a clear, domelike window in front of the eye which gathers and focuses incoming light
Describe the iris
The colored part of the eye, the iris, has two muscles. The dilator pupillae which opens under sympathetic stimulation and the constrictor pupillae which constricts under parasympathetic stimulation.
What does the lens do?
helps control the refraction of incoming light and found behind the iris
Describe the retina
located in the back of the eye, it’s like a screen of neural elements and blood vessels. It works to convert incoming photons of light into electrical signals
Describe the structure of the eye
Front to Back: cornea, anterior chamber, then the iris/pupil, posterior chamber, lens. The iris merges into the ciliary body/muscle which then merges into the choroid as you go around and to the back of the eye. The ciliary creates aqueous humor which is drained through the canal of schlemm.
What does the ciliary body do?
it produces aqueous humor that bathes the front part of the eye