Differential effects of post-training scopolamine on spatial and non-spatial learning tasks in mice

Abstract

Muscarinic antagonist scopolamine has been extensively used to model amnesia in lab rodents, but most studies have focused on the effects of pre-training scopolamine administration. Here, we examined post-training scopolamine administration in C57BL/6JRj mice. Learning was assessed in three different procedures: odor discrimination in a digging paradigm, visual discrimination in a touchscreen-based setup, and spatial learning in the Morris water maze. Scopolamine administration affected performance in the odor discrimination task. More specifically, scopolamine decreased perseverance, which facilitated reversal learning. Similar results were obtained in the visual discrimination task, but scopolamine did not affect performance in the spatial learning task. It is unlikely that these results can be explained by non-memory-related cognitive effects (e.g., attention), non-cognitive behaviours (e.g., locomotor activity) or peripheral side-effects (e.g., mydriasis). They likely relate to the various neuropharmacological actions of scopolamine.

Scopolamine blocks context-dependent reinstatement of fear responses in rats

“…The effects of post-acquisition scopolamine administration have not been well defined (Thonnard et al, 2019). Hasselmo and colleagues proposed that cholinergic neurotransmission is differently involved in acquisition (encoding) and post-acquisition processes (Hasselmo & McGaughy, 2004).…”