Memory, perception, and the ventral visual-perirhinal-hippocampal stream: Thinking outside of the boxes

Department of Experimental Psychology, University of Cambridge, Cambridge, United Kingdom.
Hippocampus (Impact Factor: 4.3). 09/2007; 17(9):898-908. DOI: 10.1002/hipo.20320
Source: PubMed

ABSTRACT The prevailing paradigm in cognitive neuroscience assumes that the brain can be best understood as consisting of modules specialised for different psychological functions. Within the field of memory, we assume modules for different kinds of memory. The most influential version of this view posits a module called the "medial temporal lobe memory system" which operates in the service of "declarative memory." This system can be contrasted with a separate "perceptual representation system" in the ventral visual stream, which is critical for perceptual learning and memory, an example of nondeclarative function. Here we question this modular memory systems view and suggest that a better way to understand the ventral visual-perirhinal-hippocampal stream is as a hierarchically organised representational continuum. We suggest that in general, rather than trying to map psychological functions onto brain modules, we could benefit by instead attempting to understand the functions of brain regions in terms of the representations they contain, and the computations they perform.

Download full-text


Available from: Tim Bussey, Jan 13, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This review presents the current status within the field of therapeutic methods used in treating neurodegenerative diseases induced by reactive oxygen species (ROS) and propose a new approach based on existing data. ROS have been implicated in conditions ranging from cardiovascular dysfunction, arthritis, cancer, to aging and age-related disorders. The organism developed several pathways to counteract these effects, base excision repair being responsible for repairing one of the major base lesions (8-oxoG) in all organisms. Epidemiological evidence suggests that cognitive stimulation makes the brain more resilient to damage or degeneration. Recent studies have linked enriched environment to reduction of oxidative stressin neurons of mice with Alzheimer-like disease but given its complexity it is not clear what specific aspect of enriched environment has therapeutic effects. Studies from molecular biology have shown that the protein p300, which is a transcription co-activator required for consolidation of memories during specific learning tasks, is at the same time involved in DNA replication and repair, playing a central role in the long-patch pathway of BER. Based on these evidences, we propose that learning tasks like novel object recognition could be tested as possible methods of BER facilitation, hence inducing DNA repair in the hippocampal neurons. If this method proves to be effective, it could be the start for designing similar tasks for humans, as a behavioral therapeutic complement to the classical drug-based therapy in treating neurodegenerative disorders.
    Neural Regeneration Research 11/2013; 8(32):3063-3070. DOI:10.3969/j.issn.1673-5374.2013.32.010 · 0.23 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Studies of people with memory impairments have shown that a specific set of brain structures in the medial temporal lobe (MTL) is vital for memory function. However, whether these structures have a role outside of memory remains contentious. Recent studies of amnesic patients with damage to two structures within the MTL, the hippocampus and the perirhinal cortex, indicated that these patients also performed poorly on perceptual tasks. More specifically, they performed worse than controls when discriminating between objects, faces and scenes with overlapping features. In order to investigate whether these perceptual deficits are reflected in their viewing strategies, we tested a group of amnesic patients with MTL damage that included the hippocampus and perirhinal cortex on a series of oddity discrimination tasks in which they had to select an odd item from a visual array. Participants' eye movements were monitored throughout the experiment. Results revealed that patients were impaired on tasks that required them to discriminate between items that shared many features, and tasks that required processing items from different viewpoints. An analysis of their eye movements revealed that they exhibited a similar viewing pattern as controls: they fixated more on the target item on trials answered correctly, but not on trials answered incorrectly. In addition, their impaired performance was not explained by an abnormal viewing- strategy that assessed their use of working memory. These results suggest that the perceptual deficits in the MTL patients are not a consequence of abnormal viewing patterns of the objects and scenes, but instead, could involve an inability to bind information gathered from several fixations into a cohesive percept. These data also support the view that MTL structures are important not only for long-term memory, but are also involved in perceptual tasks.
    Neuropsychologia 11/2012; 51(1). DOI:10.1016/j.neuropsychologia.2012.11.003 · 3.45 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this review, we will discuss the idea that the hippocampus may be involved in both memory and perception, contrary to theories that posit functional and neuroanatomical segregation of these processes. This suggestion is based on a number of recent neuropsychological and functional neuroimaging studies that have demonstrated that the hippocampus is involved in the visual discrimination of complex spatial scene stimuli. We argue that these findings cannot be explained by long-term memory or working memory processing or, in the case of patient findings, dysfunction beyond the medial temporal lobe (MTL). Instead, these studies point toward a role for the hippocampus in higher-order spatial perception. We suggest that the hippocampus processes complex conjunctions of spatial features, and that it may be more appropriate to consider the representations for which this structure is critical, rather than the cognitive processes that it mediates.
    Frontiers in Human Neuroscience 04/2012; 6:91. DOI:10.3389/fnhum.2012.00091 · 2.90 Impact Factor