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Kirwan, B.

Publications and source records attributed to Kirwan, B..

2 recordsLinked to original sources

Correcting False Memories: The Effect of Mnemonic Generalization on Original Memory Traces

False memories are a common occurrence but the impact of misremembering on the original memory trace is ill-described. While the original memory may be overwritten, it is also possible for a second false memory to exist concurrently with the original, and if a false memory exists concurrently then recovery of the original information should be possible. This study investigates first, whether false recognition overwrites the original memory representation using a mnemonic discrimination task, and second, which neural processes are associated with recovering the original memory following a false memory. Thirty-five healthy, young adults performed multiple recognition memory tests, where the design of the experiment induced participants to make memory errors in the first recognition memory test and then allowed us to determine whether the memory error would be corrected in the second test. FMRI signal associated with the encoding and retrieval processes during the experiment were investigated in order to determine the important regions for false memory correction. We found that false memories do not overwrite the original trace in all instances, as recovery of the original information was possible. Critically, we determined that recovery of the original information was dependent on higher-order processes during the formation of the false memory during the first test, and not on processing at the time of encoding nor the second test.

neuroscience

The Medial Temporal Lobe Supports Mnemonic Discrimination For Event Duration

Time has an integral role in episodic memory and previous work has implicated the medial temporal lobe in both representing time and discriminating between similar memory traces. Here we developed a novel paradigm to test mnemonic discrimination for temporal duration, as previous temporal work has largely focused on order or maintaining information over time. Thirty-five healthy, young adults completed a continuous-recognition temporal discrimination task in which participants were tasked with detecting a change of stimulus duration on the order of 0.5 seconds and whole-brain high-resolution fMRI data were acquired during this process. Analyses of behavioral results indicate that participants were successful at detecting whether the stimulus duration changed. Further, fMRI analyses revealed that successful trial performance was associated with differential processes in the left entorhinal and perirhinal cortices. Specifically, the left entorhinal cortex was differentially engaged during encoding trials that preceded Target detection, and the left perirhinal cortex was differentially engaged during successful test phase Target and Lure detections. These findings suggest that the entorhinal cortex is involved in the encoding of temporal context information and that the perirhinal cortex is representing the conjunction of item and context during retrieval.

neuroscience