Axon Physiology

Debanne, Dominique; Campanac, Émilie; Bialowas, Andrzej; Carlier, Edmond; Alcaraz, Gisèle

doi:10.1152/physrev.00048.2009

Cited by 544 publications

(552 citation statements)

References 581 publications

(722 reference statements)

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“…5D, a delay of 9.6 ± 0.6 ms occurred between VPM and ipsilateral S1, consistent with the reported 8.5-ms latency value for monosynaptic VPM to S1 projection (41). Signal then propagated from ipsilateral S1 to ipsilateral V1 through cortico-cortical circuit projections in 21.5 ± 1.6 ms, in line with the reported value of 25 ms (17), and to contralateral S1 through interhemispheric monosynaptic callosal projection in 6.7 ± 0.5 ms, consistent with the 6.0 ms estimated from reported axonal conduction velocity (42). Finally, the signal propagated in 6.2 ± 0.9 ms from ipsilateral V1 to contralateral V1 through interhemispheric callosal projection.…”

Section: Long-range Excitatory Projections Support Signal Propagation Atsupporting

confidence: 86%

Long-range projections coordinate distributed brain-wide neural activity with a specific spatiotemporal profile

Leong

Chan

Gao

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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One challenge in contemporary neuroscience is to achieve an integrated understanding of the large-scale brain-wide interactions, particularly the spatiotemporal patterns of neural activity that give rise to functions and behavior. At present, little is known about the spatiotemporal properties of long-range neuronal networks. We examined brain-wide neural activity patterns elicited by stimulating ventral posteromedial (VPM) thalamo-cortical excitatory neurons through combined optogenetic stimulation and functional MRI (fMRI). We detected robust optogenetically evoked fMRI activation bilaterally in primary visual, somatosensory, and auditory cortices at low (1 Hz) but not high frequencies (5-40 Hz). Subsequent electrophysiological recordings indicated interactions over long temporal windows across thalamo-cortical, cortico-cortical, and interhemispheric callosal projections at low frequencies. We further observed enhanced visually evoked fMRI activation during and after VPM stimulation in the superior colliculus, indicating that visual processing was subcortically modulated by low-frequency activity originating from VPM. Stimulating posteromedial complex thalamo-cortical excitatory neurons also evoked brain-wide bloodoxygenation-level-dependent activation, although with a distinct spatiotemporal profile. Our results directly demonstrate that lowfrequency activity governs large-scale, brain-wide connectivity and interactions through long-range excitatory projections to coordinate the functional integration of remote brain regions. This low-frequency phenomenon contributes to the neural basis of long-range functional connectivity as measured by resting-state fMRI.fMRI | optogenetic | brain connectivity | low frequency | thalamus T he brain is a highly complex, interconnected structure with parallel and hierarchical networks distributed within and between neural systems (1, 2). This integrative architecture dictates the underlying principles of how brain-wide neural connectivity supports and organizes sensory, behavioral, and cognitive processes (3). Recent advances in structural (2, 4) and functional connectivity (5-12) mapping, as well as neural circuit modulatory tools, such as optogenetics (13, 14), permit detailed, high-resolution neural examinations at unprecedented scales. In particular, functional connectivity mapping using resting-state functional MRI (rsfMRI) produces noninvasive visualization of slow and spontaneous hemodynamic fluctuations in humans (5-9) and animals (10-12). Coherent low-frequency (<1 Hz) fluctuations across functionally coupled, large-scale networks is an intriguing property, although the exact underlying neural bases and functional significance remain unclear. Previous studies integrating large-scale electrical recordings, voltage-sensitive dye (VSD), and Ca 2+ -imaging techniques (15-18) support the hypothesis that slow, oscillating neural activity constrains and elicits these hemodynamic fluctuations. Furthermore, low-frequency activity can temporally synchronize remote brain region...

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Section: Long-range Excitatory Projections Support Signal Propagation Atsupporting

confidence: 86%

Long-range projections coordinate distributed brain-wide neural activity with a specific spatiotemporal profile

Leong

Chan

Gao

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…The mossy fibers are projection axons of the hippocampal granule cells in the dentate gyrus, sending signals to the CA3 region. The MFB is an enlarged axon terminal (3)(4)(5) μm in diameter) forming synaptic contacts onto CA3 neurons [23][24][25] . In hippocampal slices maintained in vitro, it is possible to make simultaneous paired recording from the soma and the MFB of a given granule cell, or a presynaptic MFB and a postsynaptic CA3 pyramidal neuron.…”

Section: Establishment Of the Tight-seal Patch-clamp Techniquementioning

confidence: 99%

“…More detailed informations on axonal structure and function are available in recent reviews [5][6][7] .…”

Section: Introductionmentioning

confidence: 99%

Axonal bleb recording

Shu

2012

Neurosci. Bull.

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Patch-clamp recording requires direct accessibility of the cell membrane to patch pipettes and allows the investigation of ion channel properties and functions in specific cellular compartments. The cell body and relatively thick dendrites are the most accessible compartments of a neuron, due to their large diameters and therefore great membrane surface areas. However, axons are normally inaccessible to patch pipettes because of their thin structure; thus studies of axon physiology have long been hampered by the lack of axon recording methods. Recently, a new method of patchclamp recording has been developed, enabling direct and tight-seal recording from cortical axons. These recordings are performed at the enlarged structure (axonal bleb) formed at the cut end of an axon after slicing procedures. This method has facilitated studies of the mechanisms underlying the generation and propagation of the main output signal, the action potential, and led to the finding that cortical neurons communicate not only in action potential-mediated digital mode but also in membrane potential-dependent analog mode.

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“…The mammalian spinal cord consists of a multitude of axonal fibers 1-20 µm in diameter that carry motor stimuli from the brain to the trunk and the limbs, and the sensory information from the limbs back to the central nervous system [1][2][3] . Spinal cord injuries disrupt this information exchange leading to loss of voluntary movement [4] .…”

Section: Introductionmentioning

confidence: 99%

Polymer Fiber Probes Enable Optical Control of Spinal Cord and Muscle Function In Vivo

Froriep

Koppes

et al. 2014

Adv Funct Materials

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Restoration of motor and sensory functions in paralyzed patients requires the development of tools for simultaneous recording and stimulation of neural activity in the spinal cord. In addition to its complex neurophysiology, the spinal cord presents technical challenges stemming from its flexible fibrous structure and repeated elastic deformation during normal motion. To address these engineering constraints, we developed highly flexible fiber probes, consisting entirely of polymers, for combined optical stimulation and recording of neural activity. The fabricated fiber probes exhibit low-loss light transmission even under repeated extreme bending deformations.Using our fiber probes, we demonstrate simultaneous recording and optogenetic stimulation of neural activity in the spinal cord of transgenic mice expressing the light sensitive protein channelrhodopsin 2 (ChR2). Furthermore, optical stimulation of the spinal cord with the polymer fiber probes induces on-demand limb movements that correlate with electromyographical (EMG) activity.

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Axon Physiology

Cited by 544 publications

References 581 publications

Long-range projections coordinate distributed brain-wide neural activity with a specific spatiotemporal profile

Long-range projections coordinate distributed brain-wide neural activity with a specific spatiotemporal profile

Axonal bleb recording

Polymer Fiber Probes Enable Optical Control of Spinal Cord and Muscle Function In Vivo

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