Flavoprotein autofluorescence imaging in the cerebellar cortex in vivo

2007 ◽  
Vol 85 (15) ◽  
pp. 3221-3232 ◽  
Author(s):  
Kenneth C. Reinert ◽  
Wangcai Gao ◽  
Gang Chen ◽  
Timothy J. Ebner
Keyword(s):  
Cerebellar Cortex ◽  
Autofluorescence Imaging

Flavoprotein Autofluorescence Imaging of Neuronal Activation in the Cerebellar Cortex In Vivo

2004 ◽  
Vol 92 (1) ◽  
pp. 199-211 ◽  
Author(s):  
Kenneth C. Reinert ◽  
Robert L. Dunbar ◽  
Wangcai Gao ◽  
Gang Chen ◽  
Timothy J. Ebner
Keyword(s):  
Neuronal Activity ◽  
Cerebellar Cortex ◽  
Brain Slices ◽  
Optical Signal ◽  
Mitochondrial Metabolism ◽  
Autofluorescence Imaging ◽  
Transverse Beam ◽  
Electrophysiological Response ◽  
Indirect Measure

Autofluorescence has been used as an indirect measure of neuronal activity in isolated cell cultures and brain slices, but only to a limited extent in vivo. Intrinsic fluorescence signals reflect the coupling between neuronal activity and mitochondrial metabolism, and are caused by the oxidation/reduction of flavoproteins or nicotinamide adenine dinucleotide (NADH). The present study evaluated the existence and properties of these autofluorescence signals in the cerebellar cortex of the ketamine/xylazine anesthetized mouse in vivo. Surface stimulation of the unstained cerebellar cortex evoked a narrow, transverse beam of optical activity consisting of a large amplitude, short latency increase in fluorescence followed by a longer duration decrease. The optimal wavelengths for this autofluorescence signal were 420–490 nm for excitation and 515–570 nm for emission, consistent with a flavoprotein origin. The amplitude of the optical signal was linearly related to stimulation amplitude and frequency, and its duration was linearly related to the duration of stimulation. Blocking synaptic transmission demonstrated that a majority of the autofluorescence signal is attributed to activating the postsynaptic targets of the parallel fibers. Hypothesized to be the result of oxidation and subsequent reduction of flavoproteins, blocking mitochondrial respiration with sodium cyanide or inactivation of flavoproteins with diphenyleneiodonium substantially reduced the optical signal. This reduction in the autofluorescence signal was accomplished without altering the presynaptic and postsynaptic components of the electrophysiological response. Results from reflectance imaging and blocking nitric oxide synthase demonstrated that the epifluorescence signal is not the result of changes in hemoglobin oxygenation or blood flow. This flavoprotein autofluorescence signal thus provides a powerful tool to monitor neuronal activity in vivo and its relationship to mitochondrial metabolism.

scholarly journals Cerebellar implementation of movement sequences through feedback

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Andrei Khilkevich ◽  
Juan Zambrano ◽  
Molly-Marie Richards ◽  
Michael Dean Mauk
Keyword(s):  
Purkinje Cells ◽  
Cerebellar Cortex ◽  
General Framework ◽  
Eyelid Conditioning ◽  
Mossy Fibers ◽  
Learning Processes ◽  
Single Component ◽  
Associate Learning ◽  
Stimulation Of

Most movements are not unitary, but are comprised of sequences. Although patients with cerebellar pathology display severe deficits in the execution and learning of sequences (Doyon et al., 1997; Shin and Ivry, 2003), most of our understanding of cerebellar mechanisms has come from analyses of single component movements. Eyelid conditioning is a cerebellar-mediated behavior that provides the ability to control and restrict inputs to the cerebellum through stimulation of mossy fibers. We utilized this advantage to test directly how the cerebellum can learn a sequence of inter-connected movement components in rabbits. We show that the feedback signals from one component are sufficient to serve as a cue for the next component in the sequence. In vivo recordings from Purkinje cells demonstrated that all components of the sequence were encoded similarly by cerebellar cortex. These results provide a simple yet general framework for how the cerebellum can use simple associate learning processes to chain together a sequence of appropriately timed responses.

Feedforward Inhibition Controls the Spread of Granule Cell–Induced Purkinje Cell Activity in the Cerebellar Cortex

2007 ◽  
Vol 97 (1) ◽  
pp. 248-263 ◽  
Author(s):  
Fidel Santamaria ◽  
Patrick G. Tripp ◽  
James M. Bower
Keyword(s):  
Cerebellar Cortex ◽  
Granule Cells ◽  
Functional Organization ◽  
Cerebellar Granule Cells ◽  
Molecular Layer ◽  
Cell Activity ◽  
Excitatory Input ◽  
Cortical Inhibition ◽  
Before And After

Synapses associated with the parallel fiber (pf) axons of cerebellar granule cells constitute the largest excitatory input onto Purkinje cells (PCs). Although most theories of cerebellar function assume these synapses produce an excitatory sequential “beamlike” activation of PCs, numerous physiological studies have failed to find such beams. Using a computer model of the cerebellar cortex we predicted that the lack of PCs beams is explained by the concomitant pf activation of feedforward molecular layer inhibition. This prediction was tested, in vivo, by recording PCs sharing a common set of pfs before and after pharmacologically blocking inhibitory inputs. As predicted by the model, pf-induced beams of excitatory PC responses were seen only when inhibition was blocked. Blocking inhibition did not have a significant effect in the excitability of the cerebellar cortex. We conclude that pfs work in concert with feedforward cortical inhibition to regulate the excitability of the PC dendrite without directly influencing PC spiking output. This conclusion requires a significant reassessment of classical interpretations of the functional organization of the cerebellar cortex.

scholarly journals High-Resolution Adaptive Optics in Vivo Autofluorescence Imaging in Stargardt Disease

2019 ◽  
Vol 137 (6) ◽  
pp. 603 ◽  
Author(s):  
Hongxin Song ◽  
Ethan A. Rossi ◽  
Qiang Yang ◽  
Charles E. Granger ◽  
Lisa R. Latchney ◽  
...  
Keyword(s):  
High Resolution ◽  
Adaptive Optics ◽  
Autofluorescence Imaging ◽  
Stargardt Disease

scholarly journals Optimization of In Vivo Confocal Autofluorescence Imaging of the Ocular Fundus in Mice and Its Application to Models of Human Retinal Degeneration

2012 ◽  
Vol 53 (2) ◽  
pp. 1066 ◽  
Author(s):  
Peter Charbel Issa ◽  
Mandeep S. Singh ◽  
Daniel M. Lipinski ◽  
Ngaihang V. Chong ◽  
François C. Delori ◽  
...  
Keyword(s):  
Retinal Degeneration ◽  
Autofluorescence Imaging ◽  
Ocular Fundus
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