Adaptation to visual numerosity changes neural numerosity selectivity.

Area of Science:

• Neuroscience
• Cognitive Science
• Perception

Background:

• Numerosity perception, the ability to discern set size, is fundamental and evolutionarily conserved.
• Sensory adaptation is a key method for investigating neural underpinnings of perception.
• Previous research identified numerosity-selective neural populations with topographic organization in the human brain.

Purpose of the Study:

• To investigate how numerosity adaptation affects the selectivity of these identified neural populations.
• To explore the relationship between perceptual adaptation and neural coding of numerosity.

Main Methods:

• Utilized ultra-high field (7 Tesla) functional magnetic resonance imaging (fMRI) in human participants.
• Employed stimuli with varying numerosities (1-7 dots) for mapping selectivity.
• Interleaved low (1 dot) or high (20 dots) numerosity adapter stimuli to induce adaptation.
• Analyzed fMRI responses using population receptive field neural models of numerosity encoding.

Main Results:

• Replicated previous findings of topographic maps for numerosity-selective responses.
• Demonstrated that numerosity adaptation significantly altered preferred numerosities within these maps.
• Observed predominantly attractive biases towards the adapter's numerosity, influenced by the numerical difference.

Conclusions:

• Numerosity adaptation directly modulates neural selectivity for quantity in the human brain.
• Findings link perceptual adaptation phenomena to quantifiable changes in neural coding.
• The study provides insights into the neural mechanisms underlying numerosity perception and adaptation.