Processing number and length in the parietal cortex: Sharing resources, not a common code.

Area of Science:

• Cognitive Neuroscience
• Numerical Cognition
• Neuroimaging

Background:

• Debate exists on whether numerical cognition and non-numerical quantity processing share brain representations.
• Investigating a common generalized magnitude representation versus separate processing is crucial.

Purpose of the Study:

• To determine if the brain uses a common neural code for processing numerosity and line length.
• To explore the neural basis of magnitude representation in numerical cognition.

Main Methods:

• Acquired high-resolution functional MRI data during magnitude comparison tasks (numerosity vs. line length).
• Employed multivariate pattern analysis (MVPA) to decode quantity representations.
• Compared brain activation patterns between discrete and continuous quantity processing.

Main Results:

• Observed common recruitment of occipital and parietal cortices for both numerosity and line length processing.
• MVPA indicated similar distance-dependent magnitude coding in some overlapping regions.
• Found no evidence of a dimension-invariant, generalized quantity code across representations.

Conclusions:

• Numerical cognition and non-numerical quantity processing utilize partially overlapping neural resources.
• Representations within these shared brain regions are not based on a common, dimension-invariant neural code.
• Findings suggest distinct neural codes for discrete and continuous quantities despite shared brain areas.