The Role of Ketamine in Object Recognition Memory in Rodents

Abstract

The object recognition test (ORT) was developed to assess the role of brain structures and neurochemical systems in memory processes in rodents, mainly rats and mice. It is based on spontaneous exploratory behaviour; hence it does not require prior training of animals. It has been widely used for assessing the effects of drug compounds in various animal models of neuropsychiatric disorders. Recognition memory has been shown to be significantly compromised in schizophrenia. The latter has been linked to hypofunction of the glutamatergic N-methyl-D-aspartate receptor. Ketamine is a dissociative anaesthetic with noncompetitive N-methyl-D-aspartate receptor blockade properties. Its psychotomimetic effects led to its use to reproduce schizophrenia-like symptoms in animals. In this chapter, I describe a number of studies in which the effects of subanaesthetic and anaesthetic doses of ketamine were assessed in object recognition and object location tests. Ketamine seems to impair performance in both tests, and it appears to affect consolidation processes. The results from ketamine illustrate the significant contribution of ORT and the different novel variants of this test in encoding, consolidation and retrieval processes. © 2018 Elsevier B.V.