Motion on numbers: transcranial magnetic stimulation on the ventral intraparietal sulcus alters both numerical and motion processes.
It has often been proposed that there is a close link between representation of number and space. In the present work, single-pulse transcranial magnetic stimulation (TMS) was applied to the ventral intraparietal sulcus (VIPS) to determine effects on performance in motion detection and number comparison tasks. Participants' reaction times and thresholds for perception of laterally presented coherent motion in random dot kinematograms increased significantly when the contralateral VIPS was stimulated in contrast to the interhemispheric sulcus (Experiment 1) and to the ipsilateral VIPS (Experiment 2). In number comparison tasks, participants compared the magnitude of the laterally presented numbers 1-9 with the number 5. Again, reaction times significantly increased when TMS was applied to the contralateral VIPS in contrast to control sites. The finding that VIPS-directed TMS results in impaired efficiency in both motion perception and number comparison suggests that these processes share a common neural substrate.
Salillas
Elena
E
Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, USA. Elena.Salillas@utsa.edu
Basso
Demis
D
Baldi
Maurizia
M
Semenza
Carlo
C
Vecchi
Tomaso
T
D000328:Adult; D003210:Concept Formation / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D055641:Mathematical Concepts; D009039:Motion Perception / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D010775:Photic Stimulation; D011340:Problem Solving; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values; D012684:Sensory Thresholds / Q000502:physiology; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult