PSYC 2390 Midterm: Sensation and Perception Exam 2 Questions.docx

• School: University of Guelph
• Department: Psychology
• Course: PSYC 2390
• Professor: Lana Trick

Document Summary

Lateral summation is the convergence of rods into the same ganglion and it is an additive response. The ganglion will only fire if a threshold is reached and rods can have both an excitatory and an inhibitory response. Each rod contributes to the overall firing of the cell. Lateral inhibition is when 1 cell inhibits its neighbours when activated. Cells are connected by the lateral plexus, which transmits the inhibitory neurotransmitters. Lateral summation helps us see in low illumination and is good for vision in dark conditions. Lateral inhibition highlights edges and changes in light. One illusion in lateral inhibition is the mach bands. In the mach bands we perceive an exaggerated edge (where the light looks brighter than bright and the dark looks darker than dark). For example, say neurons that are being stimulated with light have a resting action potential of 100 action potentials per second and the neurons in the dark are 20 action potentials per second.