The Temporal Signature of Memories: Identification of a General Mechanism for Dynamic Memory Replay in Humans

Reinstatement of dynamic memories requires the replay of neural patterns that unfold over time in a similar manner as during perception. However, little is known about the mechanisms that guide such a temporally structured replay in humans, because previous studies used either unsuitable methods or paradigms to address this question. Here, we overcome these limitations by developing a new analysis method to detect the replay of temporal patterns in a paradigm that requires participants to mentally replay short sound or video clips. We show that memory reinstatement is accompanied by a decrease of low-frequency (8 Hz) power, which carries a temporal phase signature of the replayed stimulus. These replay effects were evident in the visual as well as in the auditory domain and were localized to sensory-specific regions. These results suggest low-frequency phase to be a domain-general mechanism that orchestrates dynamic memory replay in humans

Speed of time-compressed forward replay flexibly changes in human episodic memory

Remembering information from continuous past episodes is a complex task. On the one hand, we must be able to recall events in a highly accurate way that often includes exact timing; on the other hand, we can ignore irrelevant details and skip to events of interest. We here track continuous episodes, consisting of different sub-events, as they are recalled from memory. In behavioral and MEG data, we show that memory replay is temporally compressed and proceeds in a forward direction. Neural replay is characterized by the reinstatement of temporal patterns from encoding. These fragments of activity reappear on a compressed timescale. Herein, the replay of sub-events takes longer than the transition from one sub-event to another. This identifies episodic memory replay as a dynamic process in which participants replay fragments of fine-grained temporal patterns and are able to skip flexibly across sub-events

Variations in Clinical Presentations of the Simple Bone Cyst: Report of Cases

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Occurrence of hepatitis A virus in green-lipped mussels (Perna viridis)

In a preliminary survey of hepatitis A virus (HAV) in local shellfish, HAV was found present in shellfish on two out of nine separate sampling occasions conducted in the winter. No HAV was ever detected in the shellfish-rearing marine waters on same sampling occasions. The levels of faecal coliforms and coliphages in both the shellfish and the shellfish-rearing waters did not provide any indication of the likelihood of the presence or absence of HAV in the shellfish. Subsequent one-year monthly microbiological monitoring of shellfish at two sites also gave similar results in that HAV was detected in shellfish on two sampling occasions in the autumn but levels of faecal coliforms and coliphages did not provide any clue to the presence or absence of HAV. The present study suggests that direct examination of HAV in shellfish may be useful for monitoring HAV in water environment. | In a preliminary survey of hepatitis A virus (HAV) in local shellfish, HAV was found present in shellfish on two out of nine separate sampling occasions conducted in the winter. No HAV was ever detected in the shellfish-rearing marine waters on same sampling occasions. The levels of faecal coliforms and coliphages in both the shellfish and the shellfish-rearing waters did not provide any indication of the likelihood of the presence or absence of HAV in the shellfish. Subsequent one-year monthly microbiological monitoring of shellfish at two sites also gave similar results in that HAV was detected in shellfish on two sampling occasions in the autumn but levels of faecal coliforms and coliphages did not provide any clue to the presence or absence of HAV. The present study suggests that direct examination of HAV in shellfish may be useful for monitoring HAV in water environment.link_to_subscribed_fulltex