A system identification analysis of optogenetically evoked electrocorticography and cerebral blood flow responses

Cerebral blood flow patterns induced by photoactivation based on laser speckle contrast imaging

Neurovascular coupling (NVC) is crucial for maintaining brain function and holds significant implications for diagnosing neurological disorders. However, the neuron type and spatial specificity in NVC remain poorly understood. In this study, we investigated the spatiotemporal characteristics of local cerebral blood flow (CBF) driven by excitatory (VGLUT2) and inhibitory (VGAT) neurons in the mouse sensorimotor cortex. By integrating optogenetics, wavefront modulation technology, and laser speckle contrast imaging (LSCI), we achieved precise, spatially targeted photoactivation of type-specific neurons and real-time CBF monitoring. We observed three distinct CBF response patterns across different locations: unimodal, bimodal, and biphasic. While unimodal and bimodal patterns were observed in different locations for both neuron types, the biphasic pattern was exclusive to inhibitory neurons. Our results reveal the spatiotemporal complexity of NVC across different neuron types and demonstrate our method's ability to analyze this complexity in detail.

A versatile toolbox for studying cortical physiology in primates

Lesioning and neurophysiological studies have facilitated the elucidation of cortical functions and mechanisms of functional recovery following injury. Clinical translation of such studies is contingent on their employment in non-human primates (NHPs), yet tools for monitoring and modulating cortical physiology are incompatible with conventional lesioning techniques. To address these challenges, we developed a toolbox validated in seven macaques. We introduce the photothrombotic method for inducing focal cortical lesions, a quantitative model for designing experiment-specific lesion profiles and optical coherence tomography angiography (OCTA) for large-scale (~5 cm2) monitoring of vascular dynamics. We integrate these tools with our electrocorticographic array for large-scale monitoring of neural dynamics and testing stimulation-based interventions. Advantageously, this versatile toolbox can be incorporated into established chronic cranial windows. By combining optical and electrophysiological techniques in the NHP cortex, we can enhance our understanding of cortical functions, investigate functional recovery mechanisms, integrate physiological and behavioral findings, and develop neurorehabilitative treatments. MOTIVATION The primate neocortex encodes for complex functions and behaviors, the physiologies of which are yet to be fully understood. Such an understanding in both healthy and diseased states can be crucial for the development of effective neurorehabilitative strategies. However, there is a lack of a comprehensive and adaptable set of tools that enables the study of multiple physiological phenomena in healthy and injured brains. Therefore, we developed a toolbox with the capability to induce targeted cortical lesions, monitor dynamics of underlying cortical microvasculature, and record and stimulate neural activity. With this toolbox, we can enhance our understanding of cortical functions, investigate functional recovery mechanisms, test stimulation-based interventions, and integrate physiological and behavioral findings.