"This concept is in line with the behavioral observations by others who suggest that the hippocampus not only serves as a cognitive map for spatial (O'Keefe and Nadel 1978) but also for object memory through the incorporation of converging spatial and nonspatial inputs (Manns and Eichenbaum 2006, 2009). The OR task was originally construed to test preverbal infants (Fagan 1990). In humans, the importance of an intact OR ability can be seen from the debilitating effects of the failure to distinguish between familiar and new objects in neurological disorders such as Parkinson's and Alzheimer's disease and visual agnosia in brain trauma patients (Farah 1992; Grady et al. 2001; Laatu et al. 2004). "
[Show abstract][Hide abstract] ABSTRACT: Although synaptic plasticity is believed to comprise the cellular substrate for learning and memory, limited direct evidence exists that hippocampus-dependent learning actually triggers synaptic plasticity. It is likely, however, that long-term potentiation (LTP) works in concert with its counterpart, long-term depression (LTD) in the creation of spatial memory. It has been reported in rats that weak synaptic plasticity is facilitated into persistent plasticity if afferent stimulation is coupled with a novel spatial learning event. It is not known if this phenomenon also occurs in other species. We recorded from the hippocampal CA1 of freely behaving mice and observed that novel spatial learning triggers endogenous LTD. Specifically, we observed that LTD is enabled when test-pulse afferent stimulation is given during the learning of object constellations or during a spatial object recognition task. Intriguingly, LTP is significantly impaired by the same tasks, suggesting that LTD is the main cellular substrate for this type of learning. These data indicate that learning-facilitated plasticity is not exclusive to rats and that spatial learning leads to endogenous LTD in the hippocampus, suggesting an important role for this type of synaptic plasticity in the creation of hippocampus-dependent memory.
"Thus, it seemed possible that behavior in the VPC task could be driven by a reflexive or habituation-like memory quite unrelated to the explicit visual recognition that humans exhibit when they encounter familiar objects. Further, in both humans and monkeys, successful performance on the VPC task emerged earlier in development, than did successful performance on the DNMS task (for a more complete discussion of these issues, see Bachevalier, 1990; Diamond, 1990; Fagan, 1990). "
[Show abstract][Hide abstract] ABSTRACT: The medial temporal lobe includes a system of anatomically connected structures that are essential for declarative memory (conscious memory for facts and events). A prominent form of declarative memory is recognition memory (the ability to identify a recently encountered item as familiar). Recognition memory has been frequently assessed in humans and in the experimental animal. This article traces the successful development of an animal model of human medial temporal lobe amnesia, which eventually identified the structures in the medial temporal lobe important for memory. Attention is given to two prominent behavioral paradigms (delayed nonmatching to sample and tests of spontaneous novelty preference).
"Infants can form memories for visual scenes and, with development, encode them faster and retain information longer (see Fagan, 1990, for a review). Following 10 to 60 s of exposure to an item, 6- month-olds consistently look longer at a novel stimulus than at the now familiar stimulus (i.e., exhibiting a novelty preference) (Fagan, 1990). Younger infants, however, are less consistent, exhibiting a novelty preference (e.g., Pascalis, de Haan, Nelson, & de Schonen, 1998; Slater, Morison, & Rose, 1982), a familiarity preference (e.g., Richards, 1997; Rose, Gottfried, Mello-Carmina, & Bridger, 1982), or no clear preference (e.g., Wetherford & Cohen, 1973). "
[Show abstract][Hide abstract] ABSTRACT: Despite a large literature on infants' memory for visually presented stimuli, the processes underlying visual memory are not well understood. Two studies with 4-month-olds (N†=†60) examined the effects of providing opportunities for comparison of items on infants' memory for those items. Experiment 1 revealed that 4-month-olds failed to show evidence of memory for an item presented during familiarization in a standard task (i.e., when only one item was presented during familiarization). In Experiment 2, infants showed robust memory for one of two different items presented during familiarization. Thus, infants' memory for the distinctive features of individual items was enhanced when they could compare items.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.