Abstract
Loss of function of the hippocampus or frontal cortex is associated with reduced performance on memory tasks, in which subjects are incidentally exposed to cues at specific places in the environment and are subsequently asked to recollect the location at which the cue was experienced. Here, we examined the roles of the rodent hippocampus and frontal cortex in cue-directed attention during encoding of memory for the location of a single incidentally experienced cue. During a spatial sensory preconditioning task, rats explored an elevated platform while an auditory cue was incidentally presented at one corner. The opposite corner acted as an unpaired control location. The rats demonstrated recollection of location by avoiding the paired corner after the auditory cue was in turn paired with shock. Damage to either the dorsal hippocampus or the frontal cortex impaired this memory ability. However, we also found that hippocampal lesions enhanced attention directed towards the cue during the encoding phase, while frontal cortical lesions reduced cue-directed attention. These results suggest that the deficit in spatial sensory preconditioning caused by frontal cortical damage may be mediated by inattention to the location of cues during the latent encoding phase, while deficits following hippocampal damage must be related to other mechanisms such as generation of neural plasticity.
Highlights
As organisms experience their environment, they may incidentally encode the location at which particular objects or events occur, and retrieve that information later if it becomes useful.The ability of humans to latently encode and retrieve details about the context or location in which an object or event was experienced has been referred to as source memory [1], and there has been interest in developing reduced or simplified procedures to test this memory capacity
We have demonstrated that lesion of the medial prefrontal cortex impairs performance in this spatial sensory preconditioning task [24,25]
The results indicate a dissociation in the functions of the hippocampus and medial prefrontal cortex during encoding of the source location of an auditory cue
Summary
As organisms experience their environment, they may incidentally encode the location at which particular objects or events occur, and retrieve that information later if it becomes useful.The ability of humans to latently encode and retrieve details about the context or location in which an object or event was experienced has been referred to as source memory [1], and there has been interest in developing reduced or simplified procedures to test this memory capacity. In a later test phase, the images are presented at the screen center and participants are asked to respond whether the object is new or previously seen (as a test of item recognition), and if it was previously seen, to indicate the original screen location (as a test of source memory recollection). This task has been used during functional imaging studies of source memory [2,3,7]. In other source memory studies, subjects have been asked to recollect in what color font recognized words were
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
