Biology subjects

Sajda, P.

Publications and source records attributed to Sajda, P..

3 recordsLinked to original sources

bioRxiv2018

Regulation of arousal via on-line neurofeedback improves human performance in a demanding sensory-motor task

Our state of arousal can significantly affect our ability to make optimal decisions, judgments, and actions in real-world dynamic environments. The Yerkes-Dodson law, which posits an inverse-U relationship between arousal and task performance, suggests that there is a state of arousal that is optimal for behavioral performance in a given task. Here we show that we can use on-line neurofeedback to shift an individuals arousal toward this optimal state. Specifically, we use a brain computer interface (BCI) that uses information in the electroencephalogram (EEG) to generate a neurofeedback signal that dynamically adjusts an individuals arousal state when they are engaged in a boundary avoidance task (BAT). The BAT is a demanding sensory-motor task paradigm that we implement as an aerial navigation task in virtual reality (VR), and which creates cognitive conditions that escalate arousal and quickly results in task failure -- e.g. missing or crashing into the boundary. We demonstrate that task performance, measured as time and distance over which the subject can navigate before failure, is significantly increased when veridical neurofeedback is provided. Simultaneous measurements of pupil dilation and heart rate variability show that the neurofeedback indeed reduces arousal. Our work is the first demonstration of a BCI system that uses on-line neurofeedback to shift arousal state and increase task performance in accordance with the Yerkes-Dodson law.

neuroscience↗

bioRxiv2018

Parameterized expertise: Evidence for gradations of musical expertise from electroencephalographic monitoring of auditory decision-making

A musicians nervous system is thought to specialize to their mode of music production. For instance, the pianists control of hands and arms develops to facilitate greater dexterity at the keyboard, while the cellist develops control to play notes using both the fret board and/or bow. Our previous work, employing an anomalous musical event (AME) detection task, identified neural and behavioral correlates that differentiated between a specific class of musicians, cellists, and those without professional musical training and expertise. Here we investigate a fine-grain differentiation between musicians having different modes of musical production, specifically in terms of how these differences are manifested in the neural correlates identified in the AME task. We show, using electroencephalography (EEG), that both event related potentials (ERPs) and single-trial analysis of the EEG can grade musical expertise by mode of sound production. Important is that these fine-grained EEG correlates are observable absent any motor response or active music production by the individuals. We find evidence that these grades of expertise are mediated by different sensory-motor interactions emblematic of the sound production mode. More broadly, our results show that neural markers can both define types of musical expertise and decompose their source components when behavioral differences are either minute or indistinguishable.

neuroscience↗

bioRxiv2018

Spatio-temporally specific transcranial magnetic stimulation to test the locus of perceptual decision making in the human brain

Previous research modeling EEG, fMRI and behavioral data has identified three spatially distributed brain networks that activate in temporal sequence, and are thought to enable perceptual decision-making during face-versus-car categorization. These studies have linked late activation (>300ms post stimulus onset) in the lateral occipital cortex (LOC) to object discrimination processes. We applied paired-pulse transcranial magnetic stimulation (ppTMS) to LOC at different temporal latencies with the specific prediction, based on these studies, that ppTMS beginning at 400ms after stimulus onset would slow reaction time (RT) performance. Thirteen healthy adults performed a two-alternative forced choice task selecting whether a car or face was present on each trial amidst visual noise pre-titrated to approximate 79% accuracy. ppTMS, with pulses separated by 50ms, was applied at one of five stimulus onset asynchronies: -200, 200, 400, 450, or 500ms, and a sixth no-stimulation condition. As predicted, TMS at 400ms resulted in significant slowing of RTs, providing causal evidence in support of LOC contribution to perceptual decision processing. In addition, TMS delivered at -200ms resulted in faster RTs, indicating early stimulation may result in performance enhancement. These findings build upon correlational EEG and fMRI observations and demonstrate the use of TMS in predictive validation of psychophysiological models.

neuroscience↗