The role of the CAMKK pathway in object recognition memory was investigated. Rats’ performance in a preferential object recognition test was examined after local infusion into the perirhinal cortex of the CAMKK inhibitor STO-609. STO-609 infused either before or immediately after acquisition impaired memory tested after a 24h but not a 20min delay. Memory was not impaired when STO-609 was infused 20min after acquisition. The expression of two downstream reaction products of CAMKK was measured by immunohistochemical staining for phospho-CAMKIThr177 and phospho-CAMKIVThr196 at 10, 40, 70 and 100 min following the viewing of novel and familiar images of objects. Processing familiar images resulted in more pCAMKI stained neurons in the perirhinal cortex than processing novel images at the 10min and 40min delays. Perirhinal neuronal counts for pCAMKIV were lower than for pCAMKI and no differential effects of processing novel and familiar images were found for pCAMKIV. Prior infusion of STO-609 caused a reduction in pCAMKI stained neurons in response to viewing either novel or familiar images, consistent with its role as an inhibitor of CAMKK. The results establish that the CAMKK pathway within the perirhinal cortex is important for the consolidation of object recognition memory. The immunohistochemical imaging for pCAMKI indicated that CAMKI might be involved in reconsolidation mechanisms for familiar stimuli in addition to consolidation mechanisms for novel stimuli. The activation of pCAMKI after acquisition is earlier than previously reported for pCAMKII. In contrast to CAMKI and CAMKII, CAMKIV appears to be unimportant for perirhinal recognition memory processes
