Electro- and magnetoencephalography (EEG/MEG) are the means to investigate the dynamics of neuronal activity non-invasively in the human brain. However, both EEG and MEG are also sensitive to non-neural sources, which can severely complicate the interpretation. The saccadic spike potential (SP) at saccade onset has been identified as a particularly problematic artifact in EEG because it closely resembles synchronous neuronal gamma band activity. While the SP and its confounding effects on EEG have been thoroughly characterized, the corresponding artifact in MEG, the saccadic spike field (SF), has not been investigated. Here we provide a detailed characterization of the SF. We simultaneously recorded MEG, EEG, gaze position and electrooculogram (EOG). We compared the SF in MEG for different saccade sizes and directions and contrasted it with the well-known SP in EEG. Our results reveal a saccade amplitude and direction dependent, lateralized saccadic spike artifact, which was most prominent in the gamma frequency range. The SF was strongest at frontal and temporal sensors but unlike the SP in EEG did not contaminate parietal sensors. Furthermore, we observed that the source configurations of the SF were comparable for regular and miniature saccades. Using distributed source analysis we identified the sources of the SF in the extraocular muscles. In summary, our results show that the SF in MEG closely resembles neuronal activity in frontal and temporal sensors. Our detailed characterization of the SF constitutes a solid basis for assessing possible saccadic spike related contamination in MEG experiments.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.neuroimage.2011.09.020 | DOI Listing |
Cell Rep
January 2025
Department of Clinical Neurological Sciences, London Health Sciences Centre, Western University, London, ON, Canada; Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada; Western Institute for Neuroscience, Western University, London, ON, Canada.
Cortical neurons in brain slices display intrinsic spike frequency adaptation (I-SFA) to constant current inputs, while extracellular recordings show extrinsic SFA (E-SFA) during sustained visual stimulation. Inferring how I-SFA contributes to E-SFA during behavior is challenging due to the isolated nature of slice recordings. To address this, we recorded macaque lateral prefrontal cortex (LPFC) neurons in vivo during a visually guided saccade task and in vitro in brain slices.
View Article and Find Full Text PDFbioRxiv
November 2024
Laboratory for Computational Motor Control, Dept. of Biomedical Engineering Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA.
When a neuron modulates its firing rate during a movement, we tend to assume that it is contributing to control of that movement. However, null space theory makes the counter-intuitive prediction that neurons often generate spikes not to cause behavior, but to prevent the effects that other neurons would have on behavior. What is missing is a direct way to test this theory in the brain.
View Article and Find Full Text PDFInt J Psychophysiol
January 2025
Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, 5A, Butlerova str., Moscow 117484, Russia; Centre for Cognition and Decision Making, National Research University Higher School of Economics, 20, Myasnitskaya str., Moscow 101000, Russia.
Individuals with obsessive-compulsive disorder (OCD) have difficulty with regulating their emotions and show reduced functioning of inhibitory control. It was reported previously that OCD patients had delayed antisaccade response and increased error rate only when affective pictures with negative valence served as fixation stimuli in "the antisaccade emotional fixation task". Complementary to the previous research, eye movements and late positive potential (LPP) for fixation stimuli and the presaccadic positivity (PSP) and spike potential (SP) before saccade onset, were compared in two groups of OCD and healthy volunteers.
View Article and Find Full Text PDFCommun Biol
October 2024
Department of Radiology, Washington University in St. Louis, St. Louis, MO, 63110, USA.
eNeuro
August 2024
Centre for Vision Research and Centre for Integrative and Applied Neuroscience, York University, Toronto, Ontario M3J 1P3, Canada.
Single-unit (SU) activity-action potentials isolated from one neuron-has traditionally been employed to relate neuronal activity to behavior. However, recent investigations have shown that multiunit (MU) activity-ensemble neural activity recorded within the vicinity of one microelectrode-may also contain accurate estimations of task-related neural population dynamics. Here, using an established model-fitting approach, we compared the spatial codes of SU response fields with corresponding MU response fields recorded from the frontal eye fields (FEFs) in head-unrestrained monkeys () during a memory-guided saccade task.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!