Tracking instances of task evoked oxygen influxes using a novel sensitive BLE enabled wearable fNIRS device identifies mPFC role in spatial memory.

Real-world neuroimaging requires true portability and sensitivity to detect signals from neuronal activity. Conventional methods such as MRI, EEG, or PET are constrained by their size and instrumentation complexity. Near Infra-Red (NIR) based optical methods have the potential for sensitive detection with a smaller footprint. Despite rapid advances in NIR detection there is no known device that is implementable using off-the-shelf integrated microprocessors and possesses the above desired characteristics along with proven sensitivity to detect task evoked responses. Here, we present a Bluetooth Low Energy (BLE)-enabled, high-sensitivity wearable functional near-infrared spectroscopy (fNIRS) device designed for untethered cortical hemodynamic monitoring during naturalistic cognitive tasks. Our fully integrated optical sensing device merges optical data acquisition and wireless transmission into a compact, cable-free platform with a very small footprint. This enables continuous multi-channel recording without placing any constraint on the subjects movement. We validate our device for reliable detection of task-evoked oxy- and deoxy-hemoglobin dynamics in the forearm, primary motor cortex, primary visual cortex, and prefrontal cortex. Subsequently, we capture real-time forebrain activity during a screen-based learning and memory task, revealing robust goal-specific hemodynamic responses. We formulate a method to identify the instances of peak neuronal activity and follow the "task Evoked Instances of Differential Oxygen influx(tEIDO)" as the subject is engaged in a task. These results highlight the potential of our proposed fNIRS device as a mobile neuroimaging solution for next-generation brain-computer interfaces and real-world cognitive monitoring. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=79 SRC="FIGDIR/small/690628v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@1f55855org.highwire.dtl.DTLVardef@7a67b8org.highwire.dtl.DTLVardef@2f6146org.highwire.dtl.DTLVardef@9b6e0c_HPS_FORMAT_FIGEXP M_FIG C_FIG