Using parity cross-format adaptation to probe abstract number representation in the human brain

Area of Science:

• Cognitive Neuroscience
• Neuroscience
• Psychology

Background:

• The existence of abstract, format-independent numerical representations in the brain is debated.
• Previous research often used numerical magnitude, which can be confounded by quantity processing.
• The numerical property of parity offers a novel approach to investigate abstract number representation.

Purpose of the Study:

• To investigate whether the human brain possesses abstract, format-independent representations of number.
• To explore the role of numerical parity in accessing these abstract representations.
• To differentiate abstract number processing from magnitude-based processing.

Main Methods:

• Electroencephalogram (EEG) recordings were used to measure brain activity.
• Participants viewed alternating sequences of even and odd Arabic numerals.
• Parity-specific neural responses were tagged at an asymmetry frequency (3.75 Hz) derived from stimulus presentation (7.5 Hz).

Main Results:

• Significant parity asymmetry responses were observed over the occipito-temporal (OT) cortex.
• Adaptation to even numerals (cross-font) enhanced subsequent parity responses in the right OT cortex.
• Adaptation to even dot stimuli also increased parity responses, while adaptation to even number words showed a non-significant trend.

Conclusions:

• Parity is processed automatically and potentially across different numerical formats (e.g., numerals, dots).
• These findings support the existence of abstract representations for numerical properties like parity.
• Parity serves as a valuable tool for probing abstract number processing in the brain.