Figure 3. Object-memory tasks.

(A) Rats made a nonspatial choice (push or dig) toward the sand-filled jar depending on the object cue attached to the jar. (B) Behavioral performance in the OBJ-NSR task (Mean ±SEM). The PER-MUS condition resulted in significant deficits in performance compared to the ACSF and POR-MUS conditions. (C) Object-cued spatial response task. Rats made a spatial choice depending on the toy object attached to the intersection wall. (D) Behavioral performance in the OBJ-SR task (Mean ± SEM). A significant difference in performance was found between the ACSF and PER-MUS conditions. **p<0.01.

Figure 3—figure supplement 1. Multimodal versus visual OBJ-NSR tasks.

(A) Cumulative performance of the PER-MUS group across trials in the multimodal OBJ-NSR (mOBJ-NSR) task and visual OBJ-NSR (vOBJ-NSR) task. We noticed that the performance of rats in the PER-MUS group in the mOBJ-NSR task improved in later trials, possibly suggesting a switch in the animal’s dependence on specific sensory modality (e.g., from visual to tactile) during object recognition. Such trend was not observed when objects were only sampled using visual modality in the vOBJ-NSR task. In the mOBJ-NSR task, the rats were allowed to sample the object stimulus using multiple sensory modalities such as vision and tactile information. The use of olfactory information, however, was controlled by cleaning the objects every 10 trials with diluted ethanol (70%), and replacing the object with its replica. Behavioral testing in the mOBJ-NSR task was followed by the vOBJ-NSR task. In the task, the object stimuli were encased in a transparent acrylic box (6 × 6 × 4 cm) with a sliding door to restrict the perceptual access to the object to the visual modality only. The general task procedures and object-response contingencies were the same between the two versions of the task. There was a significant difference between the slopes of the performance curves for the two tasks. (B) Behavioral performance in the vOBJ-NSR task (Mean ± SEM). Significant differences in performance were found among all groups (F_(2,12) = 40.477, p<0.0001; one-way repeated ANOVA). There was a significant performance difference between ACSF and PER-MUS groups (p<0.0001), between ACSF and POR-MUS groups (p=0.001), and between PER-MUS and POR-MUS groups (p<0.001; Bonferroni-Dunn). **p<0.01, ***p<0.0001.