Rodents will spontaneously learn the location of an individual object, anability captured by the object-in-place test. This review considersthe network of structures supporting this behavioural test, as well assome potential confounds that may affect interpretation. Ahierarchical approach is adopted, as we first consider those brainregions necessary for two simpler, ‘precursor’ tests (objectrecognition and object location). It is evident that performing theobject-in-place test requires an array of areas additional to thoserequired for object recognition or object location. These additionalareas include the rodent medial prefrontal cortex and two thalamicnuclei (nucleus reuniens and the medial dorsal nucleus), both denselyinterconnected with prefrontal areas. Consequently, despite the needfor object and location information to be integrated for theobject-in-place test, for example, via the hippocampus, othercontributions are necessary. These contributions stem from howobject-in-place is a test of associative recognition, as none of theindividual elements in the test phase are novel. Parallels between thestructures required for object-in-place and for recencydiscriminations, along with a re-examination of the demands of theobject-in-place test, signal the integration of temporal informationwithin what is usually regarded as a spatial-object test.
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