VCS does not affect spatial learning or memory.

<p>Spatial reference memory and repeated acquisition were assessed in a series of water-maze tasks. (<b>a</b>) The water maze was divided virtually into zones that allowed us to determine in which quadrant the mice swam as well as distance from the platform and time in the periphery. (<b>b</b>) Mice in both treatment groups learned to find the hidden platform proficiently. (<b>c, d</b>) Three annular zones were used to assess memory during the probe trial—10, 15, and 40 cm in diam., all of which were outside the periphery but inside the target quadrant. The 10-cm annulus represented the exact size and location of the platform during training. Chronic VCS treatment did not adversely affect spatial memory on the probe trial, either measured by the traditional quadrant divisions (<b>d</b>) or the more sensitive annular analysis (<b>c</b>). (<b>e</b>) Following the probe trial mice were re-trained to find the platform in a different location every day, in 10 trials. This repeated reversals testing did not reveal any treatment differences, either at baseline or under saline. The low dose of scopolamine did not affect learning in either group, but both groups were impaired by the 3.2 mg/kg dose. An equivalent dose of the quaternary control scopolamine methylbromide, which does not cross the blood-brain barrier, did not significantly affect performance in either group, demonstrating that the performance under scopolamine 3.2 mg/kg can be attributed to centrally-mediated cognitive impairments and not non-mnemonic performance factors.