Fraction Neural Representation In Human Parietal Cortex:
Format-dependent magnitude
encoding
Research Question
Fraction Comparison Task
Fraction could take different formats: either symbolic or non-symbolic.
Format-dependent or
Format-Independent Representations?
Question: IPS encodes the numeric value of fraction of all
formats, but are they encoded in the same way?
Methods
Representational Disimmilarity Matrices (RDMs)
RDMs represent the interrelationship between fractions with
different formats and values based on research hypotheses (conceptual RDMs) or
empirical fMRI data (neural RDMs).
*Note that the log-abosolute magnitude
model (log-A) resembles the neural data in IPSs.
Construct Format-dependent representation models:
Mixing Magnitude
Models with Format RDMs
Mixing a magnitude RDM with a format RDM to produce a
format-dependent magnitude RDM.
*Note that the hybrid model (e.g., GxA-6) resembles the neural data in IPSs better than the pure magnitude model log-A above.
Multidimensional Scaling (MDS) dipicts the distances between RDMs.
Click the buttons to see each group's MDS. (*Note that the hybrid models are closer to IPS neural RDMs)
Research Results support
the Format-dependent Representation of
fraction numeric value
Relatedness Test Result
Relatedness test result shows that the format-dependent models could better explain the neural IPS RDMs than format-independent models.
Developmental Trend
Adults’s IPSs are more sensitive to the abstract magnitude information and is less format-dependent.
