Our results show the first experimental dissociation between place and temporal coding processes in frequency discrimination in normal-hearing humans. The interference with temporal coding, but Z-VAD-FMK clinical trial not with place
coding around 1000 Hz, by tDCS could be a direct result of changed auditory cortical processing or an indirect result of auditory processing at lower levels of the neuraxis exerted through a corticofugal system. Generally, the dissociation of place and temporal coding processes by anodal tDCS offers a new means of exploring cortical processes in audition. Funding was provided to M.F.T. by The University of Western Australia. We thank B. C. J. Moore and A. Sęk for providing programs we used to measure frequency selectivity and fine temporal structure. A. Sęk also provided technical assistance. The authors declare no competing financial interests. Abbreviations 2I-2AFC two-interval, two-alternative forced-choice DLF frequency difference limen ERB equivalent rectangular bandwidth LP lowest point PTC psychophysical tuning curve SPL stimulus presentation
level tDCS transcranial direct current stimulation TFS temporal fine structure “
“Consolidation of motor memories associated with skilled practice can occur both online, concurrent with practice, and offline, after practice has Everolimus molecular weight ended. The current study investigated the role of dorsal premotor cortex (PMd) in early offline motor memory consolidation of implicit sequence-specific learning. Thirty-three participants were assigned to one of three groups of repetitive transcranial magnetic stimulation (rTMS) over
left PMd (5 Hz, 1 Hz or control) immediately following practice of a novel continuous tracking task. There was no additional practice following rTMS. This procedure was repeated for 4 days. The continuous tracking task contained a repeated sequence that could be many learned implicitly and random sequences that could not. On a separate fifth day, a retention test was performed to assess implicit sequence-specific motor learning of the task. Tracking error was decreased for the group who received 1 Hz rTMS over the PMd during the early consolidation period immediately following practice compared with control or 5 Hz rTMS. Enhanced sequence-specific learning with 1 Hz rTMS following practice was due to greater offline consolidation, not differences in online learning between the groups within practice days. A follow-up experiment revealed that stimulation of PMd following practice did not differentially change motor cortical excitability, suggesting that changes in offline consolidation can be largely attributed to stimulation-induced changes in PMd.