Biology subjects

Cohen, L. G.

Publications and source records attributed to Cohen, L. G..

3 recordsLinked to original sources

bioRxiv2018

Differential brain mechanisms of selection and maintenance of information during working memory

Working memory is our ability to select and temporarily hold information as needed for complex cognitive operations. The temporal dynamics of sustained and transient neural activity supporting the selection and holding of memory content is not known. To address this problem, we recorded magnetoencephalography (MEG) in healthy participants performing a retro-cue working memory task in which the selection rule and the memory content varied independently. Multivariate decoding and source analyses showed that selecting the memory content relies on prefrontal and parieto-occipital persistent oscillatory neural activity. By contrast, the memory content was reactivated in a distributed occipito-temporal posterior network, preceding the working memory decision and in a different format that during the visual encoding. These results identify a neural signature of content selection and characterize differentiated spatiotemporal constraints for subprocesses of working memory.

neuroscience↗

bioRxiv2018

Offline coil position denoising enhances detection of TMS effects

OBJECTIVETranscranial magnetic stimulation (TMS) is extensively used in basic and clinical neuroscience. Previous work has shown substantial residual variability in TMS effects even despite use of on-line visual feedback monitoring of coil position. Here, we aimed to evaluate if off-line denoising of variability induced by neuronavigated coil position and orientation deviations can enhance detection of TMS effects.\n\nMETHODSRetrospective modeling was used to denoise the impact of common neuronavigated coil position and rotation deviations during TMS experimental sessions on motor evoked potentials (MEP) to single pulse TMS.\n\nRESULTSNeuronavigated coil deviations explained approximately 44% of total MEP amplitude variability. Offline denoising led to a 136.71% improvement in the signal to noise ratio (SNR) of corticospinal excitability measurements. CONCLUSIONS: Offline modeling enhanced detection of TMS effects by removing variability introduced by neuronavigated coil deviations.\n\nSIGNIFICANCEThis approach could allow more accurate determination of TMS effects in cognitive and interventional neuroscience.\n\nHIGHLIGHTSO_LICoil deviations impact TMS effects despite use of on-line neuronavigation feedback.\nC_LIO_LIOffline denoising of coil deviation impacts on TMS effects significantly reduced variability at trial level.\nC_LIO_LIOffline denoising also significantly improved overall SNR of TMS effects.\nC_LI

neuroscience↗

bioRxiv2018

To jump or not to jump: The Bereitschaftspotential required to jump into 192-meter abyss

Self-initiated voluntary acts, such as pressing a button, are preceded by a negative electrical brain potential, the Bereitschaftspotential (BP), that can be recorded over the human scalp using electroencephalography (EEG). Up to now, the BP required to initiate voluntary acts has only been recorded under well-controlled laboratory conditions.\n\nIt is thus not known if this form of brain activity also underlies motor initiation in possible life-threatening decision making, such as jumping into a 192-meter abyss, an act requiring extraordinary willpower. Here, we report BP before self-initiated 192-meter extreme bungee jumping across two semi-professional cliff divers (both male, mean age 19.3 years). We found that the spatiotemporal dynamics of the BP is comparable to that recorded under laboratory conditions. These results, possible through recent advancements in wireless and portable EEG technology, document for the first time pre-movement brain activity preceding possible life-threatening decision making.

neuroscience↗