Frequency-based Dissociation of Symbolic and Nonsymbolic Numerical Processing during Numerical Comparison

Area of Science:

• Cognitive Neuroscience
• Neuroscience of Numerical Cognition

Background:

• Symbolic and nonsymbolic numerical processing involve distinct cognitive operations.
• These operations spatially overlap in the parietal cortex and occur concurrently (~250 ms poststimulus).

Purpose of the Study:

• To test the hypothesis that symbolic and nonsymbolic numerical processing are segregated by distinct neural oscillatory networks.
• Specifically, to investigate high gamma (above 50 Hz) for symbolic and lower beta (12-17 Hz) for nonsymbolic processing.

Main Methods:

• Electroencephalography (EEG) signals were recorded while participants performed symbolic number and nonsymbolic quantity comparisons.
• EEG oscillatory power in different frequency bands was quantified and analyzed.

Main Results:

• Increased EEG gamma-band power was observed over frontocentral regions for more difficult symbolic comparisons.
• Increased EEG beta-band power was observed over parietal areas for more difficult nonsymbolic comparisons.

Conclusions:

• The findings demonstrate a functional dissociation in EEG oscillatory dynamics during numerical processing.
• This dissociation supports distinct neural processing for symbolic (linguistic) and nonsymbolic (approximate quantity) numerical information.