090115 Nieder

The Bernstein Center for Computational Neuroscience Freiburg

Announcement for the next

BCCN Seminar

Dr. Andreas Nieder

Department of Animal Physiology
Institute for Zoology, University of Tübingen, Germany

Neuronal representation of quantitative information in primates

Humans and animals routinely need to make decisions based on the magnitude of stimuli. While true counting and mathematics are cultural achievements that are bound to language, organisms lacking language still possess basic numerical capabilities. Comparative psychologists showed that animals discriminate numerical information, and developmental psychology experienced a breakthrough when tapping numerical cognition in human infants of only few months of age. This indicates that quantitative and numerical competence does not emerge de novo in evolution but arises from biological predispositions. We investigated the neural foundations of quantitative categories and concepts in behaving macaque monkeys in combined psychophysical/neurophysiological studies. Monkeys were trained to discriminate quantitative information of different types in delayed match-to-sample tasks. We found many neurons in the prefrontal and posterior parietal cortices encoding their preferred stimulus magnitude during sample presentation, or maintained this quantitative information ‘on line’ during a memory period. The tuning characteristics of such neurons can explain basic psychophysical effects in dealing with quantities (such distance and size effects). Tuning to the preferred quantity was largely lost whenever the monkeys made judgment errors, indicating the behavioral relevance of quantity-selective neurons. Together, the current data shed light on the question of how the primate brain deals with quantity information to guide decisions.

Host: Janina Kirsch