MEG reveals different contributions of somatomotor cortex and cerebellum to simple reaction time after temporally structured cues

Martin, Tim; Houck, Jon M.; Bish, Joel P.; Kičić, Dubravko; Woodruff, C. Chad; Moses, Sandra N.; Lee, Dustin C.; Tesche, Claudia D. · 2005 · OpenAlex-citations

DOI: 10.1002/hbm.20200

archive: archived pipeline: cataloged verified

Get this paper ↗ (DOI — opens at the source; we link to it, we don't host it)

Summary

This study investigates the neural mechanisms underlying simple reaction time (SRT) when participants anticipate targets based on temporally structured cues. Using magnetoencephalography (MEG), the researchers examined how brain activity in the somatomotor cortex, cerebellum, and other regions contributes to response latency. The experiment employed a warning stimulus paradigm where participants performed speeded button presses in response to target tones. Conditions included uncued trials, trials with two isochronous warning stimuli, and trials with three warning stimuli. Targets could arrive "on time" (consistent with the warning interval) or "early" (violating the temporal expectation). Nine participants completed the task while MEG data were recorded. Source localization identified consistent activation in auditory cortex, primary motor cortex, medial cingulate cortex, and the cerebellum. The analysis focused on two primary metrics: the onset latency of neural activity relative to the target and the variability (standard deviation) of prestimulus baseline activity. Behavioral results confirmed that cued targets elicited significantly faster reactions than uncued targets, with three warning stimuli producing faster responses than two. Additionally, targets arriving on time were responded to faster than those arriving early. The key findings revealed distinct contributions from different brain regions depending on the cueing context. Prestimulus cerebellar activity variability predicted SRT in uncued conditions and when targets arrived on time after three warning stimuli. In contrast, the onset of somatomotor cortex activity relative to the target predicted SRT after two warning stimuli (on-time) and after three warning stimuli (on-time). When targets arrived early after three warning stimuli, both prestimulus cerebellar and cingulate activity were predictive of reaction time. Notably, somatomotor onset was not significantly affected by condition in standard ANOVA, but its timing relative to the target correlated strongly with behavioral speed. These results suggest that the cerebellum and somatomotor cortex play complementary roles in temporal preparation. The cerebellum appears involved in processing temporal structure, maintaining response readiness, and predicting stimulus onset, particularly when expectations are established or violated. The somatomotor cortex contributes to the execution phase, with its activation timing directly influencing response speed once the target appears. The study highlights that temporal cueing modulates neural dynamics through both prestimulus preparatory states and post-stimulus processing speeds, offering insight into how the brain allocates resources for anticipated actions.

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed.

Summary generated by qwen3.6-27b-prismaquant on 2026-06-26; verification: verified.

Topics

Ranked by relevance to this paper. Hover a topic for its definition.

• time perception