Journal: Scientific Reports

Article Title: Cholinergic modulation of sensory processing in awake mouse cortex

doi: 10.1038/s41598-021-96696-8

Figure Lengend Snippet: Specific lesion of cortical cholinergic fibres re-shapes the amplitude and timing of tactile-evoked voltage responses in sensory cortical areas. (“ ”; “ ”). ( a ) Schematic methods. Mice received a unilateral cortical injection of mu-p75 SAP or rabbit IgG SAP Control into the left hemisphere, red dot indicates injection site. 15 days later mice were head-fixed and imaged during paw stimulation. Mouse images created with Biorender.com. ( b ) Reduction of cholinergic fibres in the contralateral cortex (visualised with acetylcholinesterase staining 15 days after mu-p75SAP injection). Percentage of cholinergic fibre loss relative to the contralateral (non-injected hemisphere). Two-way ANOVA, Areas F (2, 30) = 0.08495, p = 0.9188, Groups F (1, 30) = 276.4, p < 0.0001; Interaction F (2, 30) = 1.586, p = 0.2214. Data are mean ± SEM. (Cholinergic (ACh) lesion n = 6 mice, control n = 6 mice). ( c ) The forelimb asymmetry index is unaffected 15 days after ACh lesion. Wilcoxon Signed Rank Test, compared to 0.5, theoretical value of symmetrical use of the forelimbs, p ≥ 0.05 ACh lesion p = 0.2812, Control p = 0.9297; and unpaired t-test, t (18) = 0.8387, p = 0.4126 (ACh lesion n = 12, control n = 8). ( d ) ACh-lesioned mice show impaired performance on the accelerating rotarod 15 days after the lesion, compared with time-matched Control mice (Two-way repeated measurements ANOVA, Interaction F (3, 27) = 1.484, p = 0.2411; time F (3, 27) = 7.071, p = 0.0086; groups F (1, 9) = 6.993, p = 0.0267 (ACh lesion n = 4, control n = 7). ( e ) Sensory-evoked voltage maps in response to paw stimulation at selected times before and after stimulation (0 ms) in ACh-lesioned and Control mice. Scale bar is 1 mm. Bregma shown with a white square. Depolarised pixels red, + 0.5% ΔR/R and hyperpolarised pixels blue, − 0.5% ΔR/R. Maps contain the same data as the traces in F and G. (ACh lesion n = 58 trials, 6 mice. Control n = 61 trials, 6 mice, all 15 days after injection). Side by side videos of responses to forepaw stimulation in mice 15 days after mu-p75SAP injection and control can be found in Supplementary Video . ( f ) (i) Through-skull cranial window with mapped areas according to “The Mouse Brain in Stereotaxic Coordinates” , relative to bregma. (S1FL Forelimb area of the primary sensory cortex). Bregma shown with a white square. (ii) Average voltage traces from the S1FL area in response to Paw stimulation from Control or ACh-lesioned mice. Vertical dashed line represents stimulus onset. (iii) Maximum depolarisation amplitude, Unpaired t-test, t (117) = 2.706, p = 0.0078. (iv) Time of maximum depolarization, Mann–Whitney test, U = 1669, p = 0.5754. (v) Maximum hyperpolarisation amplitude, Unpaired t-test, t (117) = 2.122, p = 0.0360. ( g ) (i) Through-skull cranial window with mapped areas according to “The Mouse Brain in Stereotaxic Coordinates” , relative to bregma. (S1BF Barrel field of the sensory cortex). Bregma shown with a white square. (ii) Average voltage traces from the S1BF area in response to paw stimulation from Control or ACh-lesioned mice. Vertical dashed line indicates stimulation onset. (iii) Maximum depolarisation amplitude, Unpaired t-test, t (117) = 0.4137, p = 0.6799. (iv) Time of maximum depolarization, Mann–Whitney test, U = 1411, p = 0.0528. (v) Maximum hyperpolarisation amplitude, Mann–Whitney test, U = 1624, p = 0.4430. All data are mean ± SEM. * p < 0.05, ** p < 0.01, *** p < 0.001. NS non-significant. Scale bars 0.1% ΔR/R and 100 ms.

Article Snippet: Rabbit IgG-SAP , Advanced Targeting Systems , IT-35.

Techniques: Injection, Control, Staining, MANN-WHITNEY

Journal: Scientific Reports

Article Title: Cholinergic modulation of sensory processing in awake mouse cortex

doi: 10.1038/s41598-021-96696-8

Figure Lengend Snippet: Lesion of cortical cholinergic fibres modifies sensory adaptation of tactile-evoked voltage responses in S1FL. (“ ”; “ ”). ( a ) Schematic methods. Mice received a unilateral cortical injection of mu-p75 SAP or IgG SAP Control into the left hemisphere, red dot indicates injection site. 15 days later mice were head-fixed and imaged during paw stimulation. Mouse images created with Biorender.com. (b) We assessed sensory adaptation by delivering two tactile stimulations to the Paw 100 ms, 200 ms or 400 ms apart (Δt) and compared the second response in forelimb area of the primary sensory cortex, S1FL with the first. Stimulation times are indicated by blue vertical dashed lines and times of peak depolarising responses in S1FL are indicated by red vertical dashed lines. Sensory-evoked voltage responses averaged from S1FL in control mice (blue) and ACh-lesioned mice (light blue). The thick grey trace is the result of subtraction of the responses from ACh-lesioned mice from control mice, and illustrates the times when the two responses are different, ie when the thick grey line is above or below the horizontal dashed line. Below, the stimulation protocol shows how the expected peak of the second response, second of red vertical lines, coincides with the times when the ACh-lesioned response was most different to control. ( c ) Peak depolarising responses in S1FL to second stimulation 100 ms after the first are smaller in both Control and ACh-lesioned mice. (i) Sensory-evoked voltage maps 60 ms after each of a pair of stimuli 100 ms apart. S1FL (blue) area. (ACh lesion n = 64 trials, 6 mice. Control n = 44 trials, 6 mice). Bregma shown with a white square. Scalebar 1 mm. (ii) Sensory-evoked voltage responses spatially averaged from S1FL. Vertical dashed lines represent stimulus onset. (iii) Amplitudes of the second depolarising peaks in mice with the ACh lesion and Control. Mann–Whitney test between groups, U = 1107, p = 0.0601. (iv) Peak depolarisation ratio (amplitude of the second depolarising peak/amplitude of the first depolarising peak). Wilcoxon Signed Rank Test, Theoretical value = 1, ACh lesion p < 0.0001, Control p < 0.0001. Mann–Whitney test between groups, U = 1195, p = 0.1848. ( d ) In contrast to D, the amplitude of the second sensory-evoked paw response (200 ms after the first response) in S1FL is larger in mice with the ACh lesion as compared to Control. (i) Sensory-evoked voltage maps 60 ms after each of a pair of stimuli 200 ms apart. S1FL (blue) area. Bregma shown with a white square. Scalebar 1 mm. (ACh lesion n = 33 trials, 6 mice, control n = 48, 6 mice). (ii) Sensory-evoked voltage responses spatially averaged from S1FL. Vertical dashed lines represent stimulus onset. (iii) Amplitudes of the second depolarising peaks in mice with the ACh lesion and control. Mann–Whitney test between groups, U = 451, p = 0.0005. (iv) Peak depolarisation ratio (amplitude of the second depolarisation peak/amplitude of the first peak). Wilcoxon Signed Rank Test, Theoretical value = 1, ACh lesion p = 0.5602, control p < 0.0074. Mann–Whitney test between groups, U = 640, p = 0.1460. ( e ) The ACh lesion reduces the sensory evoked responses from S1FL after a second paw stimulation 400 ms after the first stimulation. (i) Sensory-evoked voltage maps 60 ms after each of a pair of stimuli 400 ms apart. S1FL (blue) area. Bregma shown with a white square. Scalebar 1 mm. Depolarised pixels are shown in red and hyperpolarised pixels in blue. (ACh lesion n = 44 trials, 6 mice, control n = 41, 6 mice). (ii) Sensory-evoked voltage responses spatially averaged from S1FL. Vertical dashed lines represent stimulus onset. (iii) Amplitudes of the second depolarising peaks in mice with the ACh lesion and control. Mann–Whitney test between groups, U = 810, p = 0.4229. (iv) Peak depolarisation ratio (amplitude of the second depolarisation peak/amplitude of the first peak). Wilcoxon Signed Rank Test, Theoretical value = 1, ACh lesion p < 0.0001, control p = 0.3095. Mann–Whitney test between groups, U = 585, p = 0.0050. c (i)– e (i) Depolarised pixels red, + 0.5% ΔR/R and hyperpolarised pixels blue, − 0.5% ΔR/R. Data are mean ± SEM. Scale bars 0.1% ΔR/R and 100 ms.

Article Snippet: Rabbit IgG-SAP , Advanced Targeting Systems , IT-35.

Techniques: Injection, Control, MANN-WHITNEY