Numerical cognition: A meta-analysis of neuroimaging, transcranial magnetic stimulation and brain-damaged patients studies.

This article offers the first comprehensive review examining the neurocognitive bases of numerical cognition from neuroimaging, Transcranial Magnetic Stimulation (TMS) and brain-damaged patients studies. We focused on the predictions derived from the Triple Code Model (TCM), particularly the assumption that the representation of numerical quantities rests on a single format-independent representation (i.e., the analogical code) involving both intraparietal sulci (IPS). To do so, we conducted a meta-analysis based on 28 neuroimaging, 12 TMS and 12 brain-damaged patients studies, including arithmetic and magnitude tasks in symbolic and non-symbolic formats. Our findings generally agree with the TCM predictions indicating that both IPS are engaged in all tasks. Nonetheless, the results of brain-damaged patients studies conflicted with neuroimaging and TMS studies, suggesting a right hemisphere lateralization for non-symbolic formats. Our findings also led us to discuss the involvement of brain regions other than IPS in the processing of the analogical code as well as the neural substrate of other codes underlying numerical cognition (i.e., the auditory-verbal code).

Tool use in left-brain-damaged patients: Difficulties in reasoning but not in estimating the physical properties of objects.

OBJECTIVE: The purpose of this study was to deepen our understanding of the cognitive bases of human tool use based on the technical reasoning hypothesis (i.e., the reasoning-based approach). This approach assumes that tool use is supported by the ability to reason about an object's physical properties (e.g., length, weight, strength, etc.) to perform mechanical actions (e.g., lever). In this framework, an important issue is to understand whether left-brain-damaged (LBD) individuals with tool-use deficits are still able to estimate the physical object's properties necessary to use the tool. METHOD: Eleven LBD patients and 12 control participants performed 3 original experimental tasks: Use-Length (visual evaluation of the length of a stick to bring down a target), Visual-Length (to visually compare objects of different lengths) and Addition-Length (to visually compare added lengths). Participants were also tested on conventional tasks: Familiar Tool Use and Mechanical Problem-Solving (novel tools). RESULTS: LBD patients had more difficulties than controls on both conventional tasks. No significant differences were observed for the 3 experimental tasks. CONCLUSION: These results extend the reasoning-based approach, stressing that it might not be the representation of length that is impaired in LBD patients, but rather the ability to generate mechanical actions based on physical object properties. (PsycINFO Database Record