Fig. 4: Syt1 is dispensable for motivation to work for food.
A Schematic representation of operant food-rewarded nose-poking protocol in Syt1 cKODA mice. B, C Time course of the number of pellets earned (B) and pokes made (C) by Syt1+/+ (green lines, n = 8 mice) and Syt1−/− (black lines, n = 10 mice) mice using FED3 feeding devices over 3 days in a fixed ratio (FR) paradigm (1 pellet for 1 poke). D Efficiency of the pokes (% of correct port entries) in the FR1 condition. E, F Time course of the number of pellets earned by Syt1+/+ and Syt1−/− mice (E) and pokes (F) over 6 days in a progressive ratio (PR) 1 paradigm (the nose-poking requirement began on FR1 and increased by 1 poke each time a pellet was earned. The requirement was reset to FR1 if no poking was performed on either the active or inactive port for 30 min). G Efficiency of the pokes (% of correct port entries) in the PR1 condition. H Maximal breaking points (poke thresholds) achieved by Syt1+/+ (green, n = 8) and Syt1−/− (black, n = 10) during each day (D) and night (N) session of the progressive ratio protocol. For each experiment, mice were placed in a 12 h/12 h light/dark cycle and the Zeitgeber time corresponds to the onset of the devices. Statistical analyses were carried out by mixed-effects ANOVA model with the Geisser–Greenhouse correction (A–F) and two-way ANOVAs followed by Šidák’s test (G). Error shading bands in (A–F) (green for Syt1+/+, light gray for Syt1−/−) and error bars in (G) represent ± SEM (ns, non-significant; *P < 0.05; #P < 0.0001). The schematic diagram of the FED3 nose-poking device is modified from https://github.com/KravitzLabDevices/FED3/blob/main/photos/mouse_feeder.svg. Source data are provided as a Source Data file.
