behavioral sciences - sensation and perception

page 53 of the MCAT review sheet document

sensory receptors

sensory nerves that respond to stimuli

sensory ganglia

collection of cell bodies outside the CNS

projection areas

areas in the brain that analyze sensory input

absolute threshold

the minimum of stimulus energy that will activate the sensory system

threshold of conscious perception

the minimum stimulus energy that will create a signal large enough in size and long enough in duration to be brought into awareness

difference threshold

the minimum difference in magnitude between 2 stimuli before one can perceive this difference

Weber’s Law

JND is proportional to the magnitude of the stimulus

signal detection theory

refers to the effects of nonsensory factors, such as experiences, motives, and expectations on perception of stimuli (response bias)

adaptation

refers to a decrease or increase in sensitivity to a stimulus

cornea

gathers and filters incoming light

iris

controls the size of the pupil, divides the front of the eye into the anterior and posterior chamber

lens

retracts incoming light to focus on the retina

aqueous humor

produced by the ciliary body, nourishes the eye and gives the eye its shape, drains through the canal of Schlemm

retina

rods and cones

retinal disparity

space between eyes, allows for binocular vision and depth

horizontal and amacrine cells

integrates signals from ganglion cells and performs edge-sharpening

support

vitreous on inside, sclera and choroid on outside

processing

parallel processing, magnocellular cells, parvocellular cells

visual pathway

eye to optic nerves to optic tracts to lateral geniculate nerves to visual radiations to visual cortex

outer ear

pinna, external auditory canal, tympanic membrane

middle ear

connected to nasal cavity by Eustachian tube

inner ear

bony labyrinth and membranous labyrinth

projection areas

superior olive (localizes sound) and inferior collicules (startle reflex)

auditory pathway

cochlea to vestibulocochlear nerve to medial geniculate nerve to auditory cortex

smell

olfactory nerves in olfactory epithelium (bypasses the thalamus)

pheromones

chemicals given by animals that affect social foraging and sexual behavior

taste

detection of dissolved compounds by taste buds in papillae

two-point threshold

minimum distance necessary between two points of stimulation on the skin such that the points will felt as two distinct stimuli

physiological zero

the normal temperature of skin to which objects are compared to

nociceptors

pain receptors

kinesthetic sense

proprioception

top-down processing

recognition based on memories and expectations

bottom-up processing

recognition based on details then the whole

Gestalt principles

proximity, similarity, continuity, closure