Combination of the VSD and IOS methods, new dyes, potassium-, chloride-, and pH sensitive dyes in vivo and in vitro.

in vitro
RH-795. 128128 pixels, and each pixel collected light from a surface of about 39m39m. Images were sampled every 1.2 ms.. Hip, hippocampus; ic, internal capsule; Str, neostriatum; VB, ventrobasal nucleus; CL, centrolateral; MD,mediodorsal; wm, white matter; L1, 23, 4, 5, 6, different cortical layers. Borders of the cortical ‘‘barrels’’ are demarcated.

slice imaging

Single-pulse stimulation of layer 1 and VB at radially sectioned cortex. Optically recorded responses are shown in the somatosensory cortex 5, 11, and 17 ms after single stimulation of layer 1 (A), VB (B), and both layer 1 and VB (C). Note how layer 1 stimulation on the other side of the cut allowed the spread of activity only through the upper layers of the cortex. (D) Layer 5 pixel profile for the three different stimulation conditions. The slopes of all of them are shown overlapping the pixel profiles (discontinuous lines).

barrel cortex imaging
The Evoked Sensory Response in Freely Moving Mice Depends Strongly on Behavior
(A)Example of a sensory response to C2 whisker deflection imaged with VSD while the mouse was sitting still and not whisking
(B)Image sequence corresponding to the cortical response shown in (A) (upper panel).
(C) During the next sweep in the same experiment, the C2 whisker deflection occurred while the same mouse was actively whisking. Only a very small sensory response was observed in the VSD images.
(D) Image sequence and quantification of the VSD signal from the response shown in (C)