Fig. 4.

Representative applications of OISI in rodents. (a) A typical triphasic response at 630 nm using traditional OISI normalized to $t=0\mathrm{s}$. 630 nm is more sensitive to HbR concentration, which leads to an increase in intensity during the hyperemic phase. An “initial dip” is observed before the hyperemic peak followed by an undershoot (adopted from Ref. 144, with permission from Springer Nature). Scale bar = 0.5 mm. (b) (Top) Representative images of WT (wild-type), J20-AD (AD), PCSK9-ATH (atherosclerosis), and J20-PCSK9-MIX (AD + ATH) mice showing $C_{\mathrm{HbT}}$ changes postelectrode insertion. Electrode insertion occurs at $t=0\mathrm{s}$. The color bar represents the percent change in $C_{\mathrm{HbT}}$ from baseline. (Bottom left) Fractional changes in $C_{\mathrm{HbT}}$ in the different mouse groups. The black vertical line represents the time the electrode was inserted at $t=0\mathrm{s}$. (Bottom right) Quantitative differences of the percent change in $C_{\mathrm{HbT}}$ due to electrode insertion-induced CSD (adapted from Ref. 145). (c) (Left) Resting-state functional connectivity maps following sham or stroke in STD or EE housing. (Top right) Intrahemispheric and (bottom right) interhemispheric node degree averaged maps of sham and stroke groups after housing in STD or EE. Stroke diminished intrahemispheric node degree in the lesioned hemisphere and reduced interhemispheric node degree in all regions in both hemispheres compared with sham STD. Exposure to EE after stroke increased intrahemispheric and interhemispheric connections compared to STD housing (adapted from Ref. 146).