Microelectrode array stimulation combined with intrinsic optical imaging: A novel tool for functional brain mapping

Abstract

Background Functional brain mapping via cortical microstimulation is a widely used clinical and experimental tool. However, data are traditionally collected point by point, making the technique very time consuming. Moreover, even in skilled hands, consistent penetration depths are difficult to achieve. Finally, the effects of microstimulation are assessed behaviorally, with no attempt to capture the activity of the local cortical circuits being stimulated. New Method We propose a novel method for functional brain mapping, which combines the use of a microelectrode array with intrinsic optical imaging. The precise spacing of electrodes allows for fast, accurate mapping of the area of interest in a regular grid. At the same time, the optical window allows for visualization of local neural connections when stimulation is combined with intrinsic optical imaging. Results We demonstrate the efficacy of our technique using the primate motor cortex as a sample application, using a combination of microstimulation, imaging and electrophysiological recordings during wakefulness and under anesthesia. Comparison with Current Method We find the data collected with our method is consistent with previous data published by others. We believe that our approach enables data to be collected faster and in a more consistent fashion and makes possible a number of studies that would be difficult to carry out with the traditional approach. Conclusions Our technique allows for simultaneous modulation and imaging of cortical sensorimotor networks in wakeful subjects over multiple sessions which is highly desirable for both the study of cortical organization and the design of brain machine interfaces.

A framework for designing data-driven optimization systems for neural modulation

“…Currently, eight-contact electrodes [10] and closed-loop devices using responsive control strategies [17] have become part of routine clinical care. Pre-clinically, electrodes with orders of magnitude more contacts [11,12,18], higherdimensional stimulation patterns [13,19], and much more complex control architectures [14,20] are being actively developed. Finally, in basic science experiments, optogenetics allows for even greater specificity through selective activation and inhibition of individual cell types with high temporal resolution [14][15][16][21][22][23][24][25].…”

Effective Connectivity Measured Using Optogenetically Evoked Hemodynamic Signals Exhibits Topography Distinct from Resting State Functional Connectivity in the Mouse

“…More empiric strategies have used transcranial magnetic stimulation ( Massimini et al 2005 ) or even direct cortical stimulation in patients undergoing surgical evaluation ( Matsumoto et al 2004 ; Entz et al 2014 ). In animals, EC most commonly is assessed invasively by delivering a stimulus (i.e., using current injected via microelectrodes ( Ferezou et al 2007 ; Histed et al 2009 ; Matsui et al 2011 ; Petkov et al 2015 ; Chernov et al 2016 )) at one locus while measuring the physiological responses at different loci ( Tolias et al 2005 ; Premereur et al 2016 ), or globally over the brain with fMRI ( Matsui et al 2012 ).…”

Review of functional and clinical relevance of intrinsic signal optical imaging in human brain mapping

“…To name a few, these include using ISOI in animal models of epilepsy, 61 – 63 incorporating ISOI with optogenetic approaches, 64 – 66 and combining ISOI with intracortical microstimulation. 19 , 41 , 67 – 71 The laboratory of Anna Roe has spearheaded an approach to trace connectivity within and between somatosensory and motor cortices in monkeys with intracortical microstimulation. 19 , 41 , 72 Figure 5 shows that when used together with microelectrical stimulation, ISOI can reveal areas of local connectivity around the site of stimulation as well as provide maps of cortical connectivity between areas of the brain at high spatial resolution.…”