Sensory physiology and perception Flashcards
What are the 4 type of sensory receptors? And their roles?
Photoreceptors - detect light
Cehmoreceptors - detect chemical changes
Thermal receptors - signal temperature changes
Nociceptors - pain or noxious stimuli.
In the somatosensory system what is the relationship between the primary afferents and the sensory receptors?
They are one and the same - the primary peripheral afferent axons are sensitive and act as receptors.
In other systems how are the primary afferents and peripheral axons related?
Receptors synapse onto the primary afferents releasing an approximate potential to the postsynaptic membrane.
How is this difference in receptors important in terms of repair?
Somatosensory primary afferents can regenerate and repair if damaged, as the peripheral nerves re grow, sensory receptors can not, leading to irreversible damage.
What is the activation threshold?
the depolarisation needed to fire and AP
What are receptor potentials?
These are slight depolarisations caused by stimulus on the receptors, enough stimulus will cause an AP, not enough has no effect, Graded potentials.
What is perceptual threshold?
Minimal stimulus strength to generale enough action potentials to be detected
What is spatial resolution?
The more receptors in a given area, the higher the spatial resolution. Allows brain to differentiate between pricks on the bodies surface.
What is a receptive field?
The region of sensory space receptors send an afferent impulse from.
What is lateral inhibition?
inhibition from the surrounding second order neurones from the region which receives the input. this allows the brain to pin point where the stimulus comes from.
What is temporal resolution?
Limited to stimulus given quickly- where the brain can not distinguish between two taps on the same receptive field.
What is the purpose of adaption?
Dampens down responses to homogenous temporal information.
What is the function of adaption and lateral inhibition.
To filter out unnecessary and unneeded information. Scults sensory information into changes of stimulus not just absolute stimulus strength.
