Intact Memory for Irrelevant Information Impairs Perception in Amnesia

Morgan D Barense,Iris I.A Groen,Andy C.H Lee,Lok-Kin Yeung,Sinead M Brady,Mariella Gregori,Narinder Kapur,Timothy J Bussey,Lisa M Saksida,Richard N.A Henson

doi:10.1016/j.neuron.2012.05.014

Abstract

SummaryMemory and perception have long been considered separate cognitive processes, and amnesia resulting from medial temporal lobe (MTL) damage is thought to reflect damage to a dedicated memory system. Recent work has questioned these views, suggesting that amnesia can result from impoverished perceptual representations in the MTL, causing an increased susceptibility to interference. Using a perceptual matching task for which fMRI implicated a specific MTL structure, the perirhinal cortex, we show that amnesics with MTL damage including the perirhinal cortex, but not those with damage limited to the hippocampus, were vulnerable to object-based perceptual interference. Importantly, when we controlled such interference, their performance recovered to normal levels. These findings challenge prevailing conceptions of amnesia, suggesting that effects of damage to specific MTL regions are better understood not in terms of damage to a dedicated declarative memory system, but in terms of impoverished representations of the stimuli those regions maintain.

Highlights

Memory loss following brain damage, for example to structures in the medial temporal lobe (MTL), is often considered to reflect a failure to consolidate memory traces that otherwise decay
The representational-hierarchical account proposes that the perirhinal cortex (PRC) can be considered an extension of the representational hierarchy within the ventral visual stream (VVS) (Barense et al, 2005; Bussey and Saksida, 2002; Bussey et al, 2002; Desimone and Ungerleider, 1989; Graham et al, 2010; Riesenhuber and Poggio, 1999)
In experiment 4, we investigated whether amnesia following damage that included PRC could be characterized by a heightened susceptibility to perceptual interference

Summary

Introduction

Memory loss following brain damage, for example to structures in the medial temporal lobe (MTL), is often considered to reflect a failure to consolidate memory traces that otherwise decay. The representational-hierarchical account proposes that the perirhinal cortex (PRC) can be considered an extension of the representational hierarchy within the ventral visual stream (VVS) (Barense et al, 2005; Bussey and Saksida, 2002; Bussey et al, 2002; Desimone and Ungerleider, 1989; Graham et al, 2010; Riesenhuber and Poggio, 1999). It is well-established that as information flows from posterior to anterior regions of the VVS, representations of visual stimulus features are organized hierarchically in increasingly complex conjunctions (Figure 1; Desimone and Ungerleider, 1989; Riesenhuber and Poggio, 1999; Tanaka, 1996). The representational-hierarchical view proposes that stimulus representations throughout the VVS and MTL are useful for any cognitive

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