Participants practiced two discrete six-key sequences for a total of 420 trials. The 1 x 6 sequence had a unique order of key presses while the 2 x 3 sequence involved repetition of a three-key segment. Both sequences showed a long interkey interval halfway the sequence indicating hierarchical sequence control in that not only the 2 x 3 but also the 1 x 6 sequence was executed as two successive motor chunks. Besides, the second part of both sequences was executed faster than the first part. This supports the earlier notion of a motor processor executing the elements of familiar motor chunks and a cognitive processor triggering either these motor chunks or individual sequence elements. Low-frequency, off-line transcranial magnetic stimulation (TMS) of the supplementary motor area (SMA) counteracted normal improvement with practice of key presses at all sequence positions. Together, these results are in line with the notion that with moderate practice, the SMA executes short sequence fragments that are concatenated by other brain structures.
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http://dx.doi.org/10.1016/s0028-3932(01)00221-4 | DOI Listing |
Nature
October 2024
Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA.
Clin Linguist Phon
August 2024
Departament de Filologia Espanyola, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Analysing spontaneous speech in individuals experiencing fluency difficulties holds potential for diagnosing speech and language disorders, including Primary Progressive Aphasia (PPA). Dysfluency in the spontaneous speech of patients with PPA has mostly been described in terms of abnormal pausing behaviour, but the temporal features related to speech have drawn little attention. This study compares speech-related fluency parameters in the three main variants of PPA and in typical speech.
View Article and Find Full Text PDFAdv Exp Med Biol
June 2024
Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands.
The human brain is a constructive organ. It generates predictions to modulate its functioning and continuously adapts to a dynamic environment. Increasingly, the temporal dimension of motor and non-motor behaviour is recognised as a key component of this predictive bias.
View Article and Find Full Text PDFBackground: Unintentional injuries disproportionately impact American Indian and Alaska Native (AI/AN) populations. Developing effective and culturally tailored data collection and intervention programs requires an understanding of past prevention efforts in AI/AN communities, but limited peer-reviewed literature on the topic is available. This scoping review aims to summarize efforts that have been published in the Primary Care Provider newsletter, a source of gray literature available through the Indian Health Service.
View Article and Find Full Text PDFNeuroimage
August 2024
Department of Psychology, University of Münster, Münster, Germany; Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, Münster, Germany.
Even though actions we observe in everyday life seem to unfold in a continuous manner, they are automatically divided into meaningful chunks, that are single actions or segments, which provide information for the formation and updating of internal predictive models. Specifically, boundaries between actions constitute a hub for predictive processing since the prediction of the current action comes to an end and calls for updating of predictions for the next action. In the current study, we investigated neural processes which characterize such boundaries using a repertoire of complex action sequences with a predefined probabilistic structure.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!