Sensory Physiology Flashcards
What are the general properties of sensory systems?
What are the types of sensory receptors?
Mechanically gated
-Converts mechanical stimulus into electrical signal
-Receptor potential (generator potential) is equivalent to graded potential
How do sensory receptive fields synapse pathways to the primary somatic sensory cortex?
What is the difference between large and small receptive fields?
How does the CNS integrate sensory information?
What are the 4 properties of stimuli that the CNS uses to distinguish one from another?
-Modality
-Location
-Intensity
-Duration
What is modality of a stimulus?
The physical stimuli being sensed, determined by the sensory receptor being activated, temperature vs touch receptor and where the pathways terminate in the brain
What is location of a stimulus?
How can lateral inhibition increase the accuracy of localization?
What is intensity and duration of a stimulus?
-Because AP amplitude is constant, intensity cannot be determined by amplitude
Intensity:
-Determined by the number of recepter being activated (population coding) and the frequency of action potentials coming from those receptors (frequency coding)
Duration:
-Stimulus is determined by how long AP’s are being activated
How does duration depend on receptor adaptation?
Explain sensory pathway specifiticy
-Each receptor is most sensitive to a particular type of stimulus
-A stimulus above threshold initiates AP’s in a sensory neuron that project to the CNS
-Stimulus intensity and duration are encoded in the pattern of AP’s reaching the CNS
-Stimulus location and modality are coded according to which receptors are activated or (in the case of sound) by the timing of receptor activation
-Each sensory pathway projects to a specific region of the cerebral cortex dedicated to a particular receptive field. The brain can then tell the origin of each incoming signal
