Fig. 2: Image-guided manipulation of somatosensory responses in the rat brain.
From: Image-guided neural activity manipulation with a paramagnetic drug
a Top: Coronal brain schematic12 at bregma = –2.8 mm, showing the location of VPL (red) bordered on the lateral side by the internal capsule (IC). Bottom: a corresponding T1-weighted (T1w) coronal image showing contrast enhancement in the VPL region following ParaMus infusion. Hypointense white matter IC signal denoted by arrowhead. b Forepaw stimulation-induced fMRI responses, in units of percent signal change (%SC), in a single animal before (top) and after (bottom) the ParaMus infusion shown in a. S1FL and S2 regions labeled; bregma coordinates in yellow. c Time course of fMRI signal in the S1FL region pre- (gray) and post-infusion (red), corresponding to data in b; stimulation blocks denoted by blue rectangles. d Change in fMRI response amplitudes (ΔRA), relative to pretreatment responses, after VPL-targeted ParaMus infusion (top, n = 5) or control infusion with gadoteridol (bottom, n = 4). e Mean relative peristimulus response time courses associated with the maps in d, pre- and post-treatment with ParaMus (top) or gadoteridol (bottom). Shading denotes SEM over five animals (top) or four animals (bottom). f Profile of mean relative T1-weighted MRI signal changes following ParaMus infusion in five animals. Control infusions lacking contrast agent produced no notable contrast enhancement. g A failed ParaMus infusion results in no enhancement in the posttreatment condition (left). Correspondingly, there is no decrease in fMRI response to forepaw stimulation after treatment (right); error bars denote SEM of responses over 10 stimulus cycles in a single animal. h Premature infusion of ParaMus is easily detectable by comparing pre- and post-treatment T1-weighted images. i Anomalous spatial distributions of ParaMus are recognized in images of two separate animals in the postinfusion condition.
