Dissociation Between Neuronal and Astrocytic Calcium Activity in Response to Locomotion in Mice.

Locomotion triggers a coordinated response of both neurons and astrocytes in the brain. Here we performed calcium (Ca) imaging of these two cell types in the somatosensory cortex in head-fixed mice moving on the airlifted platform. Ca activity in astrocytes significantly increased during locomotion from a low quiescence level.

Two-Photon Imaging of Anesthesia-Specific Alterations in Microglial Surveillance and Photodamage-Directed Motility in Mouse Cortex.

Two-photon imaging of fluorescently labeled microglia provides a direct approach to measure motility of microglial processes as a readout of microglial function that is crucial in the context of neurodegenerative diseases, as well as to understand the neuroinflammatory response to implanted substrates and brain-computer interfaces. In this longitudinal study, we quantified surveilling and photodamage-directed microglial processes motility in both acute and chronic cranial window preparations and compared the motility under isoflurane and ketamine anesthesia to an awake condition in the same animal. The isoflurane anesthesia increased the length of surveilling microglial processes in both acute and chronic preparations, while ketamine increased the number of microglial branches in acute preparation only.

Longitudinal two-photon imaging in somatosensory cortex of behaving mice reveals dendritic spine formation enhancement by subchronic administration of low-dose ketamine.

Ketamine, a well-known anesthetic, has recently attracted renewed attention as a fast-acting antidepressant. A single dose of ketamine induces rapid synaptogenesis, which may underlie its antidepressant effect. To test whether repeated exposure to ketamine triggers sustained synaptogenesis, we administered a sub-anesthetic dose of ketamine (10 mg/kg i.

Reversible Disruption of Neuronal Mitochondria by Ischemic and Traumatic Injury Revealed by Quantitative Two-Photon Imaging in the Neocortex of Anesthetized Mice.

Unlabelled: Mitochondria play a variety of functional roles in cortical neurons, from metabolic support and neuroprotection to the release of cytokines that trigger apoptosis. In dendrites, mitochondrial structure is closely linked to their function, and fragmentation (fission) of the normally elongated mitochondria indicates loss of their function under pathological conditions, such as stroke and brain trauma. Using in vivo two-photon microscopy in mouse brain, we quantified mitochondrial fragmentation in a full spectrum of cortical injuries, ranging from severe to mild.

Flat-floored air-lifted platform: a new method for combining behavior with microscopy or electrophysiology on awake freely moving rodents.

It is widely acknowledged that the use of general anesthetics can undermine the relevance of electrophysiological or microscopical data obtained from a living animal's brain. Moreover, the lengthy recovery from anesthesia limits the frequency of repeated recording/imaging episodes in longitudinal studies. Hence, new methods that would allow stable recordings from non-anesthetized behaving mice are expected to advance the fields of cellular and cognitive neurosciences.

Opposite reactivity of meningeal versus cortical microvessels to the nitric oxide donor glyceryl trinitrate evaluated in vivo with two-photon imaging.

Vascular changes underlying headache in migraine patients induced by Glyceryl trinitrate (GTN) were previously studied with various imaging techniques. Despite the long history of medical and experimental use of GTN, its effects on the brain vasculature are still poorly understood presumably due to low spatial resolution of the imaging modalities used so far. We took advantage of the micrometer-scale vertical resolution of two-photon microscopy to differentiate between the vasodynamic effects of GTN on meningeal versus cortical vessels imaged simultaneously in anesthetized rats through either thinned skull or glass-sealed cranial window.