Name: Evelyn Eger

Affiliation: INSERM Cognitive Neuroimaging Unit/CEA-Neurospin

Title: Quantity representation in the human dorsal visual stream revealed by fMRI pattern analysis

Abstract:                    

Humans have elaborate numerical abilities, believed to be grounded on a basic “number sense”, the capacity to enumerate a set of objects which is shared with us by many other animals. Macaque neurophysiology, neuropsychology and functional imaging have pointed to brain areas along the dorsal visual pathway / parietal cortex playing a critical role in numerical abilities. However, merely measuring overall regional fMRI activity in- or decreases provides limited understanding of the information encoded by neuronal populations. The talk will present findings from fMRI experiments at standard and ultra-high fields using multivariate pattern recognition to distinguish activity patterns evoked by individual quantities. Earlier work had provided evidence for information on individual numerosities in parietal sub-regions equivalent to those housing number selective neurons in macaques. More recent work demonstrates the relevance of these representations for explicit numerical judgements by relating them to behavioural numerical acuity and investigating their modulation across task contexts. Finally, the talk will discuss how numerical information emerges across the dorsal visual stream, and point to the contribution of number as opposed to other associated quantities to pattern information at different levels of the cortical hierarchy.