Time-reversed ultrasonically encoded (TRUE) focusing for deep-tissue optogenetic modulation

Brake, Joshua; Ruan, Haowen; Robinson, J. Elliott; Liu, Yan; Gradinaru, Viviana; Yang, Changhuei

doi:10.1117/12.2288331

Cited by 1 publication

(1 citation statement)

References 25 publications

(19 reference statements)

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“…If future work verifies that temporal parameters of fast natural activity, which may be protective against Alzheimer's pathology 128 , are regulated by neurometabolic or neurovascular coupling, it may be possible to deliver preventive treatments through innovative technologies such as near-infrared light 129 . Future research delineating diagnostic procedures for HDR dysregulation could lead to the design of optimal light treatment schedules to enhance mitochondrial and vascular function by targeting specific layers and cell types in the cerebral cortex 114,130 . Methods Participants.…”

Section: Discussionmentioning

confidence: 99%

Spontaneous activity changes in large-scale cortical networks in older adults couple to distinct hemodynamic morphology

Sitnikova

Hughes

Howard

et al. 2020

Preprint

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Neurovascular coupling is a dynamic core mechanism supporting brain energy demand. Therefore, even spontaneous changes in neural activity not linked directly to goal-directed behavior are expected to evoke a vascular hemodynamic response (HDR). Here, we developed a novel procedure for estimating transient neural activity states based on source-localized electroencephalogram (EEG) in combination with HDR estimation based on simultaneously acquired functional magnetic resonance imaging (fMRI). We demonstrate a readily apparent spatial correspondence between electrophysiological neural states and time-locked local HDR during rest, describing for the first time how features of neurovascular coupling may differ among unique large-scale brain networks. In the default mode network, the HDR pattern in our sample of older adults was associated with a structural surrogate marker of general cerebrovascular deterioration and predicted temporal disruption in electrophysiological activity linked to memory decline. These results demonstrate the potential of our integrated EEG/fMRI analysis for making inferences about neural and vascular processes in higher-level cognitive networks in healthy and at-risk populations.Intrinsic neural activity not explicitly associated with performing a task is an indicator of brain health. However, our understanding of how natural activity patterns arise is far from complete. The consequences of dysregulated intrinsic neuronal firing on life-sustaining cellular processes, such as gene expression and protein synthesis, are highlighted by animal models 1 . In the human brain, large-scale recordings at the cell population level link abnormal intrinsic neural activity to the progression of brain disorders, such as Alzheimer's dementia [2][3][4] . Much of what we know about intrinsic neural activity in humans comes from functional magnetic resonance imaging (fMRI), which relies on neurovascular coupling to make inferences about neural activity 5 . Inherently, variations both in neural activity and responsiveness of the associated vascular support, which is the signal detected by this imaging technique, can influence patterns in fMRI data, especially in the aging brain prone to cerebrovascular changes and patients with brain disorders accompanied by vascular comorbidities 6,7 . Therefore, new procedures for disambiguating between the neural and hemodynamic features in the human brain are needed.Studies using fMRI have demonstrated that large-scale brain networks recruited by tasks are also spontaneously reactivated during resting state [8][9][10][11] . Two recent analytic approaches, focusing on electrophysiological correlates of neural activity that are temporally resolved on rapid scales of cognition 12 , suggested that such spontaneous reactivations may constitute transient states of network activity coupled to local vascular hemodynamic response (HDR). First, a novel mathematical tool based on the Hidden Markov Model (HMM) discerned recurring transient states of spatially coordinated amplitude chan...

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