The existence of a specific and widely distributed network for spatialworking memory (WM) in humans, involving the posterior parietalcortex and the prefrontal cortex, is supported by a number ofneuroimaging studies. We used a repetitive transcranial magneticstimulation (rTMS) approach to investigate the temporal dynamics andthe reciprocal interactions of the different areas of the parieto-frontalnetwork in normal subjects performing a spatial WM task, with theaim to compare neural activity of the different areas in the delay anddecision phases of the task. Trains of rTMS at 25 Hz were deliveredover the posterior parietal cortex (PPC), the premotor cortex (SFG)and the dorsolateral prefrontal cortex (DLPFC) of the right hemi-sphere alternatively during the two phases.We found a pattern of interference of TMS during the delay phase forboth parietal and DLPFC sites of stimulation, with no effect observedfor the SFG site. When rTMS trains were applied during the decisionphase, an interference was observed selectively for DLPFC.The present study shows the existence of a parallel processing in theparieto-frontal network of spatial WM during the delay phase.Furthermore, it provides new evidence of the critical role of theDLPFC during both the delay and the decision phases. We suggest thatin DLPFC, two different networks coexist: A local neural networksubserving the decisional processes and a second neural populationfunctionally interconnected with the PPC and activated when a certainspatial information has to be kept in memory, available to use.

rTMS evidence of different delay and decision processes in a fronto-parietal neuronal network activated during spatial working memory

Koch G
Primo
;
2005

Abstract

The existence of a specific and widely distributed network for spatialworking memory (WM) in humans, involving the posterior parietalcortex and the prefrontal cortex, is supported by a number ofneuroimaging studies. We used a repetitive transcranial magneticstimulation (rTMS) approach to investigate the temporal dynamics andthe reciprocal interactions of the different areas of the parieto-frontalnetwork in normal subjects performing a spatial WM task, with theaim to compare neural activity of the different areas in the delay anddecision phases of the task. Trains of rTMS at 25 Hz were deliveredover the posterior parietal cortex (PPC), the premotor cortex (SFG)and the dorsolateral prefrontal cortex (DLPFC) of the right hemi-sphere alternatively during the two phases.We found a pattern of interference of TMS during the delay phase forboth parietal and DLPFC sites of stimulation, with no effect observedfor the SFG site. When rTMS trains were applied during the decisionphase, an interference was observed selectively for DLPFC.The present study shows the existence of a parallel processing in theparieto-frontal network of spatial WM during the delay phase.Furthermore, it provides new evidence of the critical role of theDLPFC during both the delay and the decision phases. We suggest thatin DLPFC, two different networks coexist: A local neural networksubserving the decisional processes and a second neural populationfunctionally interconnected with the PPC and activated when a certainspatial information has to be kept in memory, available to use.
2005
Koch, G; Oliveri, M; Torriero, S; Carlesimo, Ga; Turriziani, P; Caltagirone, C
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/2452713
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? 34
  • Scopus 76
  • ???jsp.display-item.citation.isi??? 70
social impact