sensory Flashcards
what are the special sensory modalities
sight hearing olfaction gustation vestibular sense of balance and spatial oreintation
what are the somatic sensory modalities
touch
pain
sense of body position
sense of temperature
what is the role of peripheral receptors
they are brain interfaces, they translate information from the environment to action potentials - language the brain understands
steps in sensory transduction
stimulus(environmental energy) -
sensory receptor
receptor potential
action potential
what happens with graded potential in receptor potentials
graded changes in membrane potential - depolarization
graded potentials decline rapidly over distance and have to be converted to action potentials
how can receptor potential be produced
by having adequate stimulus of the correct modality
also needs specific quality of stimulus
show threshold and saturation
general features of receptor cells
receptive field
quality - tuning
adaptation
what are receptive fields of neurons
area of sensory surface where adequate stimulus modulates firing of neurone
what is the receptive field for the neuron in the somatosensory cortex and the visual cortex
area of body surface - the skin
the retina
what is tuning
the range of a stimulus for which the cell respond
give example of tuning - auditory system
nerve fibres tuned to narrow band of frequencies
what do primary sensory afferents do
relay stimuli from the periphery to the CNS, single process which bifurcate
what is the role of thalamus
central brain structure that acts as a relay centre for sensory information propagating to the cortex. also recieves strong input feedback from the cortex
give an example of how cortical sensory representation is organised
somtotopy, retinatopy
