QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, August 31, 2005, 25(35):7950-7967; doi:10.1523/JNEUROSCI.1091-05.2005

This Article Full Text Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (8) Citing Articles via Google Scholar Google Scholar Articles by Ioannides, A. A. Articles by Liu, L. Search for Related Content PubMed PubMed Citation Articles by Ioannides, A. A. Articles by Liu, L.

 Previous Article  |  Next Article 

Behavioral/Systems/Cognitive
Widely Distributed Magnetoencephalography Spikes Related to the Planning and Execution of Human Saccades

Andreas A. Ioannides, Peter B. C. Fenwick, and Lichan Liu

Laboratory for Human Brain Dynamics, RIKEN Brain Science Institute, Wakoshi, Saitama 351-0198, Japan

With sufficiently fast data sampling, ubiquitous sharp transients appear in magnetoencephalography (MEG) data. Initially, no known collective neuronal activity could explain MEG signal generation well above 100 Hz, so it was assumed that these transients were entirely composed of background electronic noise that could be eliminated by filtering and averaging. Recent studies at the cellular level provided evidence for synchronous synaptic input to dendrites and volleys of near-simultaneous action potentials. MEG studies have also identified high-frequency oscillations well above 200 Hz after averaging large number of somatosensory evoked responses. In this study, we searched for evidence of high-frequency neuronal activity in the raw MEG signal using the highest sampling rate available with our hardware. Two human subjects participated in three experiments using visual cues to define planning, preparation, and execution or inhibition of saccades. Tomographic analysis identified "MEG spikes" that were widely distributed across the cortex, cerebellum, and brainstem during cue presentations and saccades. Here we demonstrate how these MEG spikes can be recorded and localized in real time and show that task demands influence their properties. The MEG spikes were organized into feedforward and corollary discharge sequences that could, when combined with the slower activity-linked processing in discrete brain areas over long periods, lasting hundreds of milliseconds. Preparation for impending saccade began as soon as relevant information became available. Cues providing partial information initiated competing motor programs for as yet undecided future actions that were maintained until cues with new information resolved the uncertainty.

Key words: magnetoencephalography; MEG; saccades; spikes; corollary discharge; brainstem; cerebellum; frontal eye fields

---

Received Aug 6, 2004; revised July 25, 2005; accepted July 25, 2005.

This article has been cited by other articles:

				A. A. Ioannides Magnetoencephalography as a Research Tool in Neuroscience: State of the Art Neuroscientist, December 1, 2006; 12(6): 524 - 544. [Abstract] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help