We have shown previously the existence of small, activity-dependent changes in intrinsic optical properties cortex that are useful for imaging cortical functional architecture. In this study we introduce a higher resolution system offers spatial and temporal exceeding achieved by most alternative techniques architecture or monitoring local cerebral blood volume oxygen saturation. addition, investigated mechanisms responsible signals evoked sensory stimuli, studied their origins wavelength...

A high spatial resolution optical imaging system was developed to visualize cerebral cortical activity in vivo. This method is based on activity-dependent intrinsic signals and does not use voltage-sensitive dyes. Images of the living monkey striate (VI) extrastriate (V2) visual cortex, taken during stimulation, were analyzed yield maps distribution cells with various functional properties. The cytochrome oxidase--rich blobs V1 stripes V2 imaged brain. In V2, no ocular dominance organization...

Optical imaging of the functional architecture cortex, based on intrinsic signals, is a useful tool for study development, organization, and function living mammalian brain. This relatively noninvasive technique small activity-dependent changes optical properties cortex. Thus far, has been performed only anesthetized animals. Here we establish that this also suitable exploring brain awake behaving primates. We designed chronic sealed chamber mounted it skull cynomolgus monkey (Macaca...

We used optical imaging of intrinsic signals to characterize the functional representations mystacial vibrissae (whiskers) in rat somatosensory cortex. Stimulation individual whiskers for 2 s at 5 Hz resulted a discrete area activity Images whisker were collected both through dura and thinned skull. characterized representation spatially temporally with two-dimensional images three-dimensional surface plots signal development cortex response stimulation. Single unit recordings verified that...

Optical Doppler tomography (ODT) is an imaging modality that takes advantage of the short coherence length a broad-band light sources to perform micrometer-scale, cross-sectional tissue structure and blood flow dynamics simultaneously. The authors review in this paper principal ODT its applications. Results from vitro vivo model studies demonstrated can map velocity profile with high spatial resolution scattering medium. detection mechanisms are illustrated using Monte Carlo simulations....

We describe a technique that uses spatially modulated near-infrared (NIR) illumination to detect and map changes in both optical properties (absorption reduced scattering parameters) tissue composition (oxy- deoxyhemoglobin, total hemoglobin, oxygen saturation) during acute ischemic injury the rat barrel cortex. Cerebral ischemia is induced using an open vascular occlusion of middle cerebral artery (MCA). Diffuse reflected NIR light (680 980 nm) from left parietal somatosensory cortex...

Research based on functional imaging and neuronal recordings in the barrel cortex subdivision of primary somatosensory (SI) adult rat has revealed novel aspects structure-function relationships this cortex. Specifically, it demonstrated that single whisker stimulation evokes subthreshold activity spreads symmetrically within gray matter from appropriate area, crosses cytoarchitectural borders SI reaches deeply into other unimodal cortices such as auditory (AI) visual (VI). It was further...

Parcellation according to function (e.g., visual, somatosensory, auditory, motor) is considered a fundamental property of sensorimotor cortical organization, traditionally defined from cytoarchitectonics and mapping studies relying on peak evoked neuronal activity. In the adult rat, stimulation single whiskers evokes activity at topographically appropriate locations within somatosensory cortex provides an example functional specificity. Here, we show that whisker also symmetrical areas...

Intrinsic signal optical imaging with red illumination (ISOI) is used extensively to provide high spatial resolution maps of stimulus-evoked hemodynamic-related signals as an indirect means map evoked neuronal activity. This generally described beginning undershoot or “dip” in that faster, more transient, and weaker compared the subsequent overshoot. In contrast, detected blood oxygen level-dependent (BOLD) functional magnetic resonance (fMRI) containing after initial dip overshoot, even...

Despite progress in reducing ischemic stroke damage, complete protection remains elusive. Here we demonstrate that, after permanent occlusion of a major cortical artery (middle cerebral artery; MCA), single whisker stimulation can induce the adult rat cortex, but only if administered within critical time window. Animals that receive early treatment are histologically and behaviorally equivalent to healthy controls have normal neuronal function. Protection cortex clearly requires reperfusion...

We have previously demonstrated protection from impending cortical ischemic stroke is achievable by sensory stimulation of the area in an adult rat model permanent middle cerebral artery occlusion (pMCAo). further that a major underpinning mechanism necessary for such system collaterals among arteries results reperfusion MCA territory. However, since collateral flow weak, it may be but not sufficient and therefore we sought other complementary mechanisms contribute to sensory-based...

The suprathreshold tonotopic organization of rat and guinea pig auditory cortex was investigated using intrinsic signal optical imaging through a thinned skull. Optical revealed that pure sine wave tone stimulation (25–40 dB) evoked activity over large cortical areas were tonotopically organized. Three-dimensional surface plots the activated "patchy" auditory-evoked consisting numerous local peaks valleys building to maximum. Subsequent detailed electrophysiological mapping in same subjects...

In this study, we implement chronic optical imaging of intrinsic signals in rat barrel cortex and repeatedly quantify the functional representation a single whisker over time. The success for more than 1 month enabled an evaluation normal dynamic range sensory representation. individual animals period several weeks, found that: (i) average spatial extent quantified C2 is surprisingly large--1.71 mm2 (area at half-height); (ii) location consistent; (iii) there are ongoing but nonsystematic...

The molecular mechanisms that coordinate the functional organization of mammalian neocortex are largely unknown. We tested involvement a putative guidance label, ephrin-A5, in somatosensory cortex by quantifying representations individual whiskers vivo adult ephrin-A5 knock-out mice, using intrinsic signal optical imaging. In wild-type mice is expressed gradient during development. we found spatial change amount cortical territory shared whisker across cortex, as well distance between...