On the neuro-cognitive foundations of basic auditory number processing: an fMRI study.
BACKGROUND
It is widely agreed that numbers automatically activate a magnitude representation. Nevertheless, so far no systematic evaluation of the neuro-cognitive correlates has been provided for the case of auditorily presented numbers.


METHODS
To address this question, we presented spoken number words in three different tasks (passive listening, magnitude comparison, parity judgement) as well as spoken pseudowords in an fMRI study.


RESULTS
We found IPS activation typically associated with magnitude processing in all tasks with numerical stimuli only. Interestingly, directly contrasting the two semantic tasks magnitude comparison (magnitude-relevant) and parity judgement (magnitude-irrelevant) revealed a left lateralized predominance within the IPS for the processing of parity information as compared to a right lateralization for number magnitude for auditorily presented number words.


CONCLUSIONS
In summary, our results suggest a highly automatic activation of number magnitude for spoken number words similar to previous observations for visually presented numbers, but also indicate that the issue of hemispheric asymmetries deserves specific consideration.
Klein
Elise
E
Department of Neurology, Section Neuropsychology, University Hospital, RWTH Aachen University, Germany. klein@neuropsych.rwth-aachen.de
Moeller
Korbinian
K
Nuerk
Hans-Christoph
HC
Willmes
Klaus
K
D000161:Acoustic Stimulation; D001307:Auditory Perception / Q000502:physiology; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D007839:Functional Laterality; D006801:Humans; D007600:Judgment / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D055641:Mathematical Concepts; D008606:Mental Processes / Q000502:physiology*; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000502:physiology; D015203:Reproducibility of Results; D012660:Semantics; D013060:Speech; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult