Fig. 4.

PACT monitoring of in vitro neural activities in GCaMP6f-expressing mouse brain slices. (a) Schematic of the high-speed PACT system, with wide-field illumination and parallel acoustic detection. The GCaMP6f-expressing brain slice was immersed in a regular aCSF solution in the imaging chamber. (b) PACT images of the GCaMP6f-expressing brain slice in a clear medium (left) and through a 2-mm-thick scattering Intralipid solution (right, reduced optical scattering coefficient $10{\mathrm{cm}}^{-1}$). (c) PACT of the neural activity in a GCaMP6f-expressing mouse brain slice in response to high-potassium perfusion. The fractional PA amplitude change (shown in color) is superimposed on the baseline image (shown in gray). (d) Time courses of fractional PA amplitude changes from four representative regions (I, II, III, and IV) as indicated in (c). The solid lines are fittings using a bell-shaped dose-response model. (Video 5, MP4, 2046 KB [URL: https://doi.org/10.1117/1.JBO.27.9.096004.s5]; Video 6, MP4, 265 KB [URL: https://doi.org/10.1117/1.JBO.27.9.096004.s6])