The neurophysiology of decision making: rate differences and log likelihood ratios

Опубликовано 6 сентября 2016, 5:25

With little sophistication, the spike rates from sensory neurons can be used to approximate useful statistics for decision making. In the context of deciding between two sensory hypotheses, a simple difference in spike rate between sensory neurons with opposite selectivity is proportional to the log likelihood ratio in favor of one sensory interpretation over another. I will describe neural recording and stimulation experiments from the alert monkey that demonstrate that the brain uses such a difference to make decisions about the direction of motion in a 2-alternative direction discrimination task. The accumulation of this difference to threshold explains the speed and accuracy of simple decisions. I will attempt to address the question of how general is the approximation to log likelihood ratio and what this might mean for neural coding in general.