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1.
Neurophotonics ; 4(3): 031205, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28018935

ABSTRACT

Intrinsic optical imaging as developed by Grinvald et al. is a powerful technique for monitoring neural function in the in vivo central nervous system. The advent of this dye-free imaging has also enabled us to monitor human brain function during neurosurgical operations. We briefly describe our own experience in functional mapping of the human somatosensory cortex, carried out using intraoperative optical imaging. The maps obtained demonstrate new additional evidence of a hierarchy for sensory response patterns in the human primary somatosensory cortex.

2.
J Physiol Sci ; 66(4): 293-301, 2016 Jul.
Article in English | MEDLINE | ID: mdl-26719289

ABSTRACT

Throughout our investigations on the ontogenesis of the electrophysiological events in early embryonic chick hearts, using optical techniques to record membrane potential probed with voltage-sensitive dyes, we have introduced a novel concept of "functiogenesis" corresponding to "morphogenesis". This article gives an account of the framework of "functiogenesis", focusing on the cardiac pacemaker function and the functional organization of the pacemaking area.


Subject(s)
Heart/embryology , Heart/physiology , Myocardial Contraction/physiology , Animals , Chick Embryo , Electrophysiological Phenomena , Membrane Potentials/physiology
3.
Adv Exp Med Biol ; 859: 213-42, 2015.
Article in English | MEDLINE | ID: mdl-26238055

ABSTRACT

The functional organization of the vertebrate central nervous system (CNS) during the early phase of development has long been unclear, because conventional electrophysiological means have several technical limitations. First, early embryonic neurons are small and fragile, and the application of microelectrodes is often difficult. Second, the simultaneous recording of electrical activity from multiple sites is limited, and as a consequence, response patterns of neural networks cannot be assessed. Optical recording techniques with voltage-sensitive dyes have overcome these obstacles and provided a new approach to the analysis of the functional development/organization of the CNS. In this review, we provide detailed information concerning the recording of optical signals in the embryonic nervous system. After outlining methodological considerations, we present examples of recent progress in optical studies on the embryonic nervous system with special emphasis on two topics. The first is the study of how synapse networks form in specific neuronal circuits. The second is the study of non-specific correlated wave activity, which is considered to play a fundamental role in neural development. These studies clearly demonstrate the utility of fast voltage-sensitive dye imaging as a powerful tool for elucidating the functional organization of the vertebrate embryonic CNS.


Subject(s)
Central Nervous System/physiology , Fluorescent Dyes/chemistry , Membrane Potentials/physiology , Neurons/physiology , Synapses/physiology , Voltage-Sensitive Dye Imaging/methods , Animals , Brain Waves/physiology , Central Nervous System/embryology , Central Nervous System/ultrastructure , Chick Embryo , Embryo, Mammalian , Mice , Microelectrodes , Nerve Net/embryology , Nerve Net/physiology , Nerve Net/ultrastructure , Neurons/ultrastructure , Optical Devices , Rats , Synapses/ultrastructure , Voltage-Sensitive Dye Imaging/instrumentation
5.
J Neurosurg ; 103(3): 414-23, 2005 Sep.
Article in English | MEDLINE | ID: mdl-16235671

ABSTRACT

OBJECT: Intrinsic optical signals in response to somatosensory stimuli were intraoperatively recorded during brain tumor surgery. In the present study, the authors report on the use of this technique as an intraoperative guide for the safe resection of tumors adjacent to or within the sensorimotor cortex. METHODS: In 14 patients with tumors adjacent to or within the sensorimotor cortex, intrinsic optical signals in response to somatosensory stimuli were recorded by illuminating the brain surface with Xe white light and imaging the reflected light passing through a bandpass filter (605 nm). Results were compared with intraoperative recordings of sensory evoked potentials in all 14 patients and with noninvasive mapping modalities such as magnetoencephalography and positron emission tomography in selected patients. In all but two patients, the somatosensory optical signals were recorded on the primary sensory cortex. Optical signals elicited by stimulation of the first and fifth digits and the three branches of the trigeminal nerve were recorded at different locations on the sensory strip. This somatotopic information was useful in determining the resection border in patients with glioma located in the sensorimotor cortex. CONCLUSIONS: Optical imaging of intrinsic signals is a useful technique with superior spatial resolution for delineating the somatotopic representation of human primary sensory cortex. Furthermore, it can be used as an intraoperative monitoring tool to improve the safety and accuracy of resections of brain tumors adjacent to or within the sensorimotor cortex.


Subject(s)
Brain Mapping/methods , Brain Neoplasms/surgery , Glioma/surgery , Somatosensory Cortex/anatomy & histology , Somatosensory Cortex/surgery , Adult , Aged , Female , Humans , Intraoperative Period , Magnetoencephalography , Male , Middle Aged , Neurosurgical Procedures/methods , Optics and Photonics , Positron-Emission Tomography , Somatosensory Cortex/physiology
6.
Neuroimage ; 17(3): 1240-55, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12414264

ABSTRACT

We examined neural response patterns evoked by peripheral nerve stimulation in in vivo rat spinal cords using an intrinsic optical imaging technique to monitor neural activity. Adult rats were anesthetized by urethane, and laminectomy was performed between C5 and Th1 to expose the dorsal surface of the cervical spinal cord. The median, ulnar, and radial nerves were dissected, and bipolar electrodes were implanted in the forelimb. Changes in optical reflectance were recorded from the dorsal cervical spinal cord in response to simultaneous stimulation of the median and ulnar nerves using a differential video acquisition system. In the region of the cervical spinal cord, intrinsic optical signals were detected between C5 and Th1 at wavelengths of 605, 630, 730, 750, and 850 nm: the image with the largest signal intensity and highest contrast was obtained at 605 nm. The signal intensity and response area expanded with an increase in the stimulation intensity and varied with the depth of the focal plane of the macroscope. The intrinsic optical response was mostly eliminated by Cd(2+), suggesting that the detected signals were mainly mediated by postsynaptic mechanisms activated by sensory nerve fibers. Furthermore, we succeeded in imaging neural activity evoked by individual peripheral nerve stimulation. We found that the response areas related to each peripheral nerve exhibited different spatial distribution patterns and that there were animal-to-animal variations in the evoked neural responses in the spinal cord. The results obtained in this study confirmed that intrinsic optical imaging is a very useful technique for acquiring fine functional maps of the in vivo spinal cord.


Subject(s)
Image Processing, Computer-Assisted/instrumentation , Microscopy, Video/instrumentation , Peripheral Nerves/physiology , Spinal Cord/physiology , Synaptic Transmission/physiology , Animals , Electric Stimulation , Equipment Design , Evoked Potentials/physiology , Male , Rats , Rats, Wistar , Sensitivity and Specificity
7.
Cereb Cortex ; 12(3): 269-80, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11839601

ABSTRACT

We performed intrinsic optical imaging of neuronal activity induced by peripheral stimulation from the human primary somatosensory cortex during brain tumor surgery for 11 patients. After craniotomy and dura reflection, the cortical surface was illuminated with a xenon light through an operating microscope. The reflected light passed through a bandpass filter, and we acquired functional images using an intrinsic optical imaging system. Electrical stimulation of the median nerve, or the first and fifth digits, induced biphasic intrinsic optical signals which consisted of a decrease in light reflectance followed by an increase. The decrease in light reflectance was imaged, and we identified a neural response area within the crown of the postcentral gyrus. In experiments on first and fifth digit stimulation, we identified optical responses in separated areas within the crown of the postcentral gyrus, i.e. near the central sulcus and near the postcentral sulcus. In the former response area, separate representations of the two fingers were observed, whereas in the latter response area, the two fingers were represented in the same region. A similar somatotopic representation was observed with electrical stimulation of the first and third branches of the trigeminal nerve. These results seem to support the hypothesis of hierarchical organization in the human primary somatosensory cortex.


Subject(s)
Brain Mapping , Brain Neoplasms/surgery , Monitoring, Intraoperative/methods , Neurons/physiology , Somatosensory Cortex/physiology , Trigeminal Nerve/physiology , Adult , Aged , Electric Stimulation , Evoked Potentials, Somatosensory/physiology , Female , Fingers/innervation , Humans , Male , Median Nerve/cytology , Median Nerve/physiology , Middle Aged , Neural Pathways , Optics and Photonics/instrumentation , Somatosensory Cortex/cytology , Trigeminal Nerve/cytology
8.
Dev Growth Differ ; 25(2): 193-200, 1983.
Article in English | MEDLINE | ID: mdl-37281271

ABSTRACT

A congenital double-hearted chick embryo was found among 16,171 embryos, which was at the 11 somite stage of development. The pacemaking activity of its double heart was monitored simultaneously from 9 different regions by optical methods. The right and left half hearts were tubular, and in both, spontaneous rhythmical action potentials and beating were detected, and differences were detected in their rhythms. Action potentials were also monitored in a malformed embryonic heart formed by partial fusion of the primordia. The results are discussed in relation to genesis of intrinsic pacemaking activity in cardiac primordia and to a spatial gradient of rhythmicity in the early stages of cardiogenesis.

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