Effects of feline immunodeficiency virus on cognition and behavioral function in cats

Experimental intravenous challenge of 8-week old cats with the Maryland iso late of feline immunodeficiency virus, Maryland isolate (FIV-MD) was invest igated for its effects on cognitive and behavioral function at 12 months po stinfection. Six cats infected with FIV-MD were compared with age-matched c ontrols on several behavioral measures. These measures included an open fie ld observation, locomotion tests, traversing planks of various widths for f ood reinforcement, and a spatial learning task. No group differences were o bserved on any measure of locomotion. Differences were present with explora tory and stationary activity in the open field observation, with infected c ats exhibiting higher levels of exploratory activity and in less stationary activity compared with that of control cats. In the plank-walking experime nt, infected cats were less able to successfully cross progressively narrow er planks compared with control animals. A holeboard paradigm was construct ed to test spatial learning and memory, in which cats were required to loca te food reinforcement based on position in the holeboard array. As a group, FIV-infected cats committed more reference (exploring an unbaited cup) and working memory (returning to a previously visited baited cup) errors than control cats. The main difference demonstrated was a higher activity level and associated distractibility in FIV-infected cats that appears to be rela ted to their overall deficient performance when learning new tasks. These r esults indicate that behavioral function is altered and cognition is quanti tatively impaired in FIV-infected cats.