FOS and pneumocystosis: Post hoc analysis revealed that the number of working memory effort-elicited c-Fos+ cells was significantly higher in the chronic PCP group than in the chronic saline group in layer 2–3 of the PL (p < 0.01), and that the number of c-Fos+ cells was significantly higher at 90 min after the working memory effort relative to basal condition (at 0 min after the working memory effort) in the chronic PCP group (p < 0.001) (Fig 2F).