Dr. Ben M. Harvey and Ms Evi Hendrikx from University of Utrecht are visiting SISSA


Tuesday, 20 June, 2023 - 11:00 to 14:00
Cognitive Neuroscience seminar by Ben M. Harvey and Evi Hendrikx
Talk details are following :
‘Human quantity processing, from sensory to cognitive systems’

Ben Harvey

Human perception of physical quantities like numerosity and event timing supports many cognitive functions, from foraging to mathematical and scientific thought. Investigation of the underlying neural processes has focussed on quantity-tuned neural responses, which respond maximally to different numerosities or timings in different neural populations. Here I will describe 7T fMRI studies in which we show quantity-tuned neural populations in many areas of the human brain and for many quantities. These are spatially organised to map the quantity across the cortical surface. I will then discuss recent studies in which we reveal how these quantity-tuned responses are derived from responses in sensory systems, how they are then transformed between different brain areas, and how responses to different quantities are related. I will first show how straightforward analyses of visual images can determine their numerosity with little effect of item size or spacing, and that this analysis predicts responses to numerosity in early visual cortex and neural network models more closely than numerosity itself. Once quantity-tuned responses have been derived, I will show how responses to visual numerosity and haptic numerosity are related. Finally, I will describe a set of brain areas whose responses depend on working memory load near those showing quantity-tuned responses. I propose that this grouping allows a linking of physical quantity representations and working memory, supporting higher cognitive functions. Together, these results give an integrated overview of quantity-tuned neural response, their derivation in sensory systems, and their extension into higher-level cognitive processing.

‘Hierarchical transitions of cortical quantity representations of visual numerosity and timing’

Evi Hendrikx

Humans and many animals use perception of multiple quantities (e.g., object number, object size, and event timing) to guide behavior and decisions. Such quantities show perceptual interactions, predominantly ascribed to a generalized magnitude system with shared neural responses across quantities. Recently, 7-Tesla fMRI and neural model-based analyses revealed partially overlapping networks of cortical maps with topographically organized quantity-tuned responses for such quantities. Here, we assess the similarities and differences between networks of numerosity- and timing-tuned responses. First, similar to response patterns for event number, we find a transition from monotonically increasing responses in early sensory areas to location-independent timing-tuned neural responses in later areas. Second, responses to numerosity and timing are initially derived separately, but are increasingly overlapping towards superior maps. Third, the preferred quantities of these shared neural populations are not generally indicative of a common quantity representation. Overall, we see a similar hierarchical emergence of numerosity- and timing-tuned responses from sensory processing areas. These quantity responses are increasingly brought together, which may underlie behavioral interactions and be beneficial to accessing shared comparison and action planning systems.