Recognition memory: Material, processes, and substrates

Abstract

The proposal that a system centering on the perirhinal cortex is responsible for familiarity discrimination, particularly for single items, whereas a system centering on the hippocampus is responsible for recollective and more complex associational aspects of recognition memory is reviewed in the light of recent findings. In particular, the proposal is reviewed in relation to recent animal work with rats and results from human clinical studies. Notably, progress has been made in determining potential neural memory substrate mechanisms within the perirhinal cortex in rats. Recent findings have emphasized the importance of specifying the type of material, the type of test, and the strategy used by subjects to solve recognition memory tests if substrates are to be accurately inferred. It is to be expected that the default condition is that both the hippocampal and perirhinal systems will contribute to recognition memory performance. Indeed, rat lesion experiments provide examples of where cooperation between both systems is essential. Nevertheless, there remain examples of the independent operation of the hippocampal and perirhinal systems. Overall, it is concluded that most, though not all, of the recent findings are in support of the proposal. However, there is also evidence that the systems involved in recognition memory need to include structures outside the medial temporal lobe: there are significant but as yet only partially defined roles for the prefrontal cortex and sensory association cortices in recognition memory processes.

The rat perirhinal cortex: A review of anatomy, physiology, plasticity, and function

“…Delatour and Witter (2002) do not differentiate between the lateral and medial entorhinal cortices but they do report a rostral-caudal topography in the termini of the projections. The presence of reciprocal projections between the parahippocampal region and the medial prefrontal cortex points to a functional relationship between these areas and a number of behavioural studies point towards a role for the medial prefrontal cortex in memory formation (Aggleton and Brown, 2006;Brown et al, 2010). Unfortunately, as far as the authors are aware, no electrophysiological studies have been done on any of the projections between the medial prefrontal and the perirhinal cortices in the rat.…”

“…Ennaceur and Delacour (1988) propose that the strength of this task is that it reflects spontaneous behaviour in the animal, therefore it is a ''pure'' memory test without the need for any rule learning and as such, it is easily comparable across species. Recently, there have been a number of comprehensive reviews of the object recognition task and in particular we refer the reader to reviews on the one trial object recognition task (Dere et al, 2007) and on the neural substrates underlying recognition memory (Eichenbaum et al, 2007;Brown et al, 2010;Clark and Squire, 2010;Warburton and Brown, 2010).…”

“…Recognition memory itself can be divided into two broad processes: familiarisation and recollection (Aggleton and Brown et al, 2010;Warburton and Brown, 2010). These two processes are difficult to dissociate in animal models, where familiarity ends and recollection begins is up for debate (Wixted and Squire, 2008;and see Wixted et al, 2010 for how this is being addressed in human medial temporal lobe studies) but Brown and Aggleton (2001) have predicted that the perirhinal cortex should underlie familiarisation and the hippocampus should be involved in recollection.…”

“…Although no lesion studies have yet been published on the roles of the hippocampus and perirhinal cortex in the object-in-place task, perirhinal lesions lead to impairments on a radial arm maze variation of the object-in-place task (Bussey et al, 2001). However, Brown et al (2010) have reported that Barker and Warburton have submitted a study for publication which shows that interaction between the hippocampus and perirhinal cortex in order to complete the object-in-place task. Additionally, perirhinal NMDA receptors have been demonstrated to underlie short-term objectin-place memory (Barker and Warburton, 2008).…”

“…The main behavioural role identified for the perirhinal cortex is recognition memory (Mumby and Pinel, 1994;Suzuki, 1996;Liu and Bilkey, 2001;Mumby et al, 2002bMumby et al, , 2007Winters and Bussey, 2005a;Hannesson et al, 2005;Albasser et al, 2009;Brown et al, 2010) but roles for the perirhinal cortex in fear conditioning (Suzuki, 1996) and in spatial memory-related tasks (Wiig and Bilkey, 1994;Glenn et al, 2003;Abe et al, 2009) will also be discussed. Additionally, we will review the developing evidence for the perirhinal cortex in perceptual processing that is typically not addressed in the wider learning and memory literature (Bussey et al, 2003.…”