Brain, Vol. 121, No. 8, 1533-1544,
August 1, 1998
© 1998 Oxford University Press
The effects of transcranial magnetic stimulation over the dorsolateral prefrontal cortex on suppression of habitual counting during random number generation
AbstractRandom number generation is an attention-demanding task that engages working memory and executive processes. Random number generation requires holding information 'on line', suppression of habitual counting, internally driven response generation and monitoring of responses. Evidence from PET studies suggests that the dorsolateral prefrontal cortex (DLPFC) is involved in the generation of random responses. We examined the effects of short trains of transcranial magnetic stimulation (TMS) over the left or right DLPFC or medial frontal cortex on random number generation in healthy normal participants. As in previous evidence, in control trials without stimulation participants performed poorly on the random number generation task, showing repetition avoidance and a tendency to count. Brief disruption of processing with TMS over the left DLPFC changed the balance of the individuals' counting bias, increasing the most habitual counting in ones and reducing the lower probability response of counting in twos. This differential effect of TMS over the left DLPFC on the balance of the subject's counting bias was not obtained with TMS over the right DLPFC or the medial frontal cortex. The results suggest that, with disruption of the left DLPFC with TMS, habitual counting in ones that has previously been suppressed is released from inhibition. From these findings a network modulation model of random number generation is proposed, whereby suppression of habitual responses is achieved through the modulatory influence of the left DLPFC over a number-associative network in the superior temporal cortex. To allow emergence of appropriate random responses, the left DLPFC inhibits the superior temporal cortex to prevent spreading activation and habitual counting in ones.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
R. C. Helmich, E. Aarts, F. P. de Lange, B. R. Bloem, and I. Toni Increased Dependence of Action Selection on Recent Motor History in Parkinson's Disease J. Neurosci., May 13, 2009; 29(19): 6105 - 6113. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Knoch, P. Brugger, and M. Regard Suppressing versus Releasing a Habit: Frequency-dependent Effects of Prefrontal Transcranial Magnetic Stimulation Cereb Cortex, July 1, 2005; 15(7): 885 - 887. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. H. Salat, J. A. Kaye, and J. S. Janowsky Greater Orbital Prefrontal Volume Selectively Predicts Worse Working Memory Performance in Older Adults Cereb Cortex, May 1, 2002; 12(5): 494 - 505. [Abstract] [Full Text] [PDF] |
||||
![]() |
E Watkins and R G Brown Rumination and executive function in depression: an experimental study J. Neurol. Neurosurg. Psychiatry, March 1, 2002; 72(3): 400 - 402. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Stoffers, H.W. Berendse, J.B. Deijen, and E.C. Wolters Motor perseveration is an early sign of Parkinson's disease Neurology, December 11, 2001; 57(11): 2111 - 2113. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Oliveri, P. Turriziani, G.A. Carlesimo, G. Koch, F. Tomaiuolo, M. Panella, and C. Caltagirone Parieto-frontal Interactions in Visual-object and Visual-spatial Working Memory: Evidence from Transcranial Magnetic Stimulation Cereb Cortex, July 1, 2001; 11(7): 606 - 618. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Jahanshahi, C. M. A. Ardouin, R. G. Brown, J. C. Rothwell, J. Obeso, A. Albanese, M. C. Rodriguez-Oroz, E. Moro, A. L. Benabid, P. Pollak, et al. The impact of deep brain stimulation on executive function in Parkinson's disease Brain, June 1, 2000; 123(6): 1142 - 1154. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. M. Mottaghy, M. Hungs, M. Brugmann, R. Sparing, B. Boroojerdi, H. Foltys, W. Huber, and R. Topper Facilitation of picture naming after repetitive transcranial magnetic stimulation Neurology, November 1, 1999; 53(8): 1806 - 1806. [Abstract] [Full Text] |
||||




