Figure 8: Accelerated odour discrimination times revealed in a longitudinal paradigm.
From: Disinhibition of olfactory bulb granule cells accelerates odour discrimination in mice
(a) Learning curves. Cineol and eugenol (CvE) were used for task habituation. Test odours, AA and EB (AAvEB), and their binary mixture in a 60:40 ratio (6/4v4/6) were used to measure the discrimination times before and after rAAV-Cre injection (mean±s.e.m.). Control mice (n=9) and GABRB3lox/lox (n=9) neither differed in learning before (ANOVA; CvE: F=3.084, P=0.08; AAvEB: F=0.655, P=0.420; 6v4: F=0.523, P=0.471) nor after rAAV-Cre injection (AAvEB: F=0.004, P=0.95; 6v4: F=3.208, P=0.076). The coloured bars (simple odours: light blue; binary mixtures: light green) depict the trials used for the quantifications in b–d. (b) Odour discrimination accuracy (mean±s.e.m.) was not significantly different for simple odours (control: 96.3±0.3%, n=9; GABRB3lox/lox: 95±0.4%, n=9; ANOVA; P=0.077) or binary mixtures (control: 93±1.41%, n=9; GABRB3lox/lox: 95±0.4%, n=9; ANOVA; P=0.313). After rAAV-Cre injection, both groups of mice continued to perform equally well for simple odours (control: 97.8±0.35%, n=9; GABRB3ΔGCL: 97±0.8%, n=9; ANOVA; P=0.593) and for the binary mixtures (control: 96±0.5%, n=9; GABRB3ΔGCL: 96±0.35%, n=9; ANOVA; P=0.945). (c) Odour discrimination times. Before rAAV-Cre injection, control (n=9) and GABRB3lox/lox (n=9) did not differ in ODTs (mean±s.e.m.) of simple odours (control: 291±11 ms; GABRB3lox/lox 280±16 ms; ANOVA; F=1.614; P=0.17) and binary mixtures (control: 320±9 ms; GABRB3lox/lox: 313±16 ms; ANOVA; F=0.979; P=0.52); however, the ODTs between simple odours and binary mixtures differed significantly (control: *P=0.038; GABRB3lox/lox: *P=0.047; t-test). After rAAV-Cre injection, GABRB3ΔGCL had faster ODTs of simple odours (control: 263±12 ms; GABRB3ΔGCL 216±13 ms) and binary mixtures (control 306±9 ms; GABRB3ΔGCL 237±14 ms; ANOVA, simple odours: F=4.654, *P=0.047; binary mixtures: F=9.212, ***P=0.008). (d) ITI as an indicator of motivation. Before rAAV-Cre injection, control mice (simple odours: 19±2 s; binary mixtures: 17±0.7 s; n=9) and GABRB3lox/lox mice (simple odours: 15±0.7 s; binary mixtures: 15±0.99 s; n=9) do not differ significantly in the ITI (mean±s.e.m.; ANOVA; F=1.93; P=0.18). After Cre injection, control mice (simple odours: 18±1 s; binary mixtures: 16±1 s; n=9) and GABRB3ΔGCL mice (simple odours: 17.6±1.6 s; binary mixtures: 14.2±0.8 s; n=9) also did not differ significantly in the ITI (mean±s.e.m.; ANOVA; F=3.621; P=0.078).
