Introduction to Cognitive Psychology - Department of Psychological ...

Prof. Greg Francis 8/14/12Receptive fieldsAction potentialPSY 200Greg FrancisWith enough excitatory input, a cell produces anaction potential that sends a signal down its axonto other cells But a single action potential has little effectLecture 06If the input stays present, the cell producesanother, and another,…How do you recognize yourgrandmother? A rapid series of action potentials can influence othercellsThe number of action potentials in a certainlength of time determines the firing rate of thecellPurdue UniversityPurdue UniversityFiring rateSpecificity8 spikes (action potentials) during 300 ms Firing rate of 27 Hz (27 spikes per second)Two key questions in cognitive neuroscience are What stimulus (or stimuli) makes a given cell fire at a strongrate?» something red?» a pen?» your grandmother? What does it mean when a given cell fires strongly?» You are thinking of something?» Seeing something?» Remembering something?Purdue UniversityPurdue UniversityReceptive fieldThe set of stimuli that reliably changes acells firing rate.A stimulus could excite the cell above normal firing rateOr inhibit the cell below normal firing rateReceptive fieldReceptive fields are very useful for studies of spatial perceptionTouch involves sensitivity to pressure on skinThe loops indicate theregions where a singleneuron responds topressurePurdue UniversityPurdue UniversityPSY 200: Intro. to Cognitive Psychology 1