Figure 2.

Bilateral lesions of area 5 cause the loss of a long-lasting working memory of an obstacle. A, Task for measuring memory of an obstacle. An animal walks forward, steps over an obstacle with the forelegs, and pauses. While paused, the obstacle is removed, and some time later the animal resumes walking. Memory of the obstacle is indicated by an elevated trajectory of the paw (thick line) over the previous location of the obstacle. See supplemental video, available at www.jneurosci.org as supplemental material. B, Example of memory loss in cat 2. Scatter plot showing the maximum toe height versus pause duration before (open circles) and 2 d after (filled circles) bilateral lesions of area 5. The shaded area shows the range of toe heights (mean ± SDs) when the obstacle was not present at any time. Before the lesions, the memory of obstacle height was maintained for tens of seconds. After the lesions, there was a complete loss of memory for pause durations greater than ∼5 s. Note that after the lesions there was little or no loss of memory for very short pause durations.