BIOL 121 Lecture Notes - Lecture 18: Receptive Field, Afferent Nerve Fiber, Axon Terminal
Document Summary
Coding- representation of stimuli characteristics modality, strength, location) within the ap signal. Sensory unit- smallest unit of sensory perception. One afferent neuron and all of its receptor endings. Each sensory unit has a receptive field. Modality-aps from any given receptor always perceived as the adequate stimulus. A larger stimulus also causes a higher frequency of ap. The more ion channels the easier it is to fire another ap during the relative refractive period. Also encoded by the number of sensory units responding. Stimulus location- our primary sensory cortices are spatially- mapped. Spatial acuity- the ability to precisely identify the location ofa stimulus. The ability to distinguish between 2 stimuli that are very close together. Number of receptive fields per given area of skin. Convergence- many receptors converging on a single afferent neuron (make receptor field bigger) Acuity is increased by receptor field overlap.
