VSDI: a new era in functional imaging of cortical dynamics

Abstract

During the last few decades, neuroscientists have benefited from the emergence of many powerful functional imaging techniques that cover broad spatial and temporal scales. We can now image single molecules controlling cell differentiation, growth and death; single cells and their neurites processing electrical inputs and sending outputs; neuronal circuits performing neural computations in vitro; and the intact brain. At present, imaging based on voltage-sensitive dyes (VSDI) offers the highest spatial and temporal resolution for imaging neocortical functions in the living brain, and has paved the way for a new era in the functional imaging of cortical dynamics. It has facilitated the exploration of fundamental mechanisms that underlie neocortical development, function and plasticity at the fundamental level of the cortical column.

Optical Strategies for Sensing Neuronal Voltage Using Quantum Dots and Other Semiconductor Nanocrystals

“…[3][4][5][6][7][8] Nevertheless, though a useful correlation often exists between Ca 2+ dynamics and neuronal spiking across a range of spike frequencies, the slowkinetics and saturation of [Ca 2+ ]-related fluorescent signals constrain the utility of Ca 2+ imaging as a means of probing spiking dynamics in many neuron types. 4,9 Numerous voltage-sensitive indicators 1,[10][11][12][13][14][15][16][17][18] permit direct imaging of cellular membrane potentials. Organic voltage-sensitive dyes have allowed functional mapping studies in awake mammals 14 and studies of individual cells' dynamics in invertebrates 19 and mammalian brain slices.…”

“…4,9 Numerous voltage-sensitive indicators 1,[10][11][12][13][14][15][16][17][18] permit direct imaging of cellular membrane potentials. Organic voltage-sensitive dyes have allowed functional mapping studies in awake mammals 14 and studies of individual cells' dynamics in invertebrates 19 and mammalian brain slices. 20 However, such studies have often been constrained by the propensities of voltage-sensitive dyes toward photobleaching, phototoxicity, and nonspecific background labeling.…”

Imaging synaptic inhibition in transgenic mice expressing the chloride indicator, Clomeleon

“…Voltage-sensitive dyes, Ca 2+ indicators, intrinsic signal imaging and fMRI, have been used to image neural activity over dimensions ranging from individual synapses to large populations of neurons (Mao et al, 2001;Mrsic-Flogel et al, 2003;Grinvald and Hildesheim, 2004;Baker et al, 2005). However, the signals employed by these methods mainly rely on neuronal excitation.…”

Wavelet-based multi-resolution statistics for optical imaging signals: Application to automated detection of odour activated glomeruli in the mouse olfactory bulb

“…An important reason of this success is due to its capability to observe neuronal activity at many points in space simultaneously, and this in vivo (or in vitro) at spatial levels ranging from cellular to network scales (c.f. Grinvald and Hildesheim, 2004). For example, optical imaging permitted to visualize ensembles of cells sharing the same function inside various sensory areas of the mammalian brain (Grinvald and Hildesheim, 2004), but it was also used (although in a different context) to record membrane potential in the entire dendritic arborisation of a single neuron (Djurisic et al, 2004).…”

“…Grinvald and Hildesheim, 2004). For example, optical imaging permitted to visualize ensembles of cells sharing the same function inside various sensory areas of the mammalian brain (Grinvald and Hildesheim, 2004), but it was also used (although in a different context) to record membrane potential in the entire dendritic arborisation of a single neuron (Djurisic et al, 2004). Such a broad range of possibilities cannot to be expected from classical electrophysiology.…”