Facts and Figures: Neuro-functional foundations and cognitive processes of numerical magnitude processing and arithmetic fact retrieval

• Applicants: Professor Dr. Hans-Otto Karnath; Dr. Elise Klein
• Subject Area: Biological Psychology and Cognitive Neuroscience
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 400857833

The present project aims at identifying cognitive processes and neuro-functional foundations of numerical magnitude information and arithmetic fact retrieval by means of multivariate lesion analysis and diffusion tensor imaging (DTI). The distinction between these two representations is the most significant procedural differentiation in numerical cognition according to the triple-code model. Static and dynamic aspects (neuro-cognitive plasticity) of numerical magnitude processing and arithmetic fact retrieval as well as their functional-anatomical foundations will be assessed in stroke patients and healthy controls via parallelized cross-sectional and longitudinal experimental (training-) studies at different time onsets. Spatial-numerical associations are examined as an indicator for the processing of numerical magnitude. The parallelized experimental design enables to address identical questions regarding magnitude processing and arithmetic fact retrieval in stroke patients and healthy controls. On this occasion, analysing different patient groups by means of multivariate lesion analysis and DTI allow to identify causal relationships of cognitive processing and the underlying neural correlates. At the same time, the influence of pathological interferences can be excluded by examining healthy controls in parallelized experiments. Based on the assumptions of the triple-code model it is possible to predict differential performance in various numerical tasks in both, healthy controls and stroke patients, the latter at certain times post infarct. More precisely, multivariate lesion analysis immediately following a stroke allows for differential causal structure-function mapping (i.e. functional deficits in numerical (sub)processes due to lesioned parts of the networks underlying numerical cognition) and whether certain parts of white and grey matter have to be lesioned simultaneously. In the chronic phase of a stroke, potential re-organisation processes within and between the neural networks of numerical magnitude and arithmetic fact retrieval can be investigated (i.e. whether certain cognitive (sub)processes can be taken over by other neuro-anatomical regions to compensate for functional deficits). The longitudinal comparison allows for drawing conclusions whether certain lesion patterns in the acute phase can predict the course of numerical impairments. By means of DTI possible fiber disconnections can be identified and analyzed, which might impair functionally unimpaired brain regions. In sum, the results gained from the proposed project would extend our understanding of (un)impaired number processing, permit prognostic statements and allow for implications for diagnosis and intervention of numerical impairments.

• DFG Programme: Research Grants