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Recognition memory is the ability to recognize previously encountered objects. Even this relatively simple, yet extremely fast, ability requires the coordinated activity of large‐scale brain networks. However, little is known about the sub‐second dynamics of these networks. The majority of current studies into large‐scale network dynamics is primarily based on imaging techniques suffering from either poor temporal or spatial resolution. We investigated the dynamics of large‐scale functional brain networks underlying recognition memory at the millisecond scale. Specifically, we analyzed dynamic effective connectivity from intracranial electroencephalography while epileptic subjects (n = 18) performed a fast visual recognition memory task. Our data‐driven investigation using Granger causality and the analysis of communities with the Louvain algorithm spotlighted a dynamic interplay of two large‐scale networks associated with successful recognition. The first network involved the right visual ventral stream and bilateral frontal regions. It was characterized by early, predominantly bottom‐up information flow peaking at 115 ms. It was followed by the involvement of another network with predominantly top‐down connectivity peaking at 220 ms, mainly in the left anterior hemisphere. The transition between these two networks was associated with changes in network topology, evolving from a more segregated to a more integrated state. These results highlight that distinct large‐scale brain networks involved in visual recognition memory unfold early and quickly, within the first 300 ms after stimulus onset. Our study extends the current understanding of the rapid network changes during rapid cognitive processes. [ABSTRACT FROM AUTHOR]

Several studies pertaining to déjà vu have consistently made a connection with the perirhinal region, a region located below the hippocampus. This idea is strengthened by the fact that déjà vu is an erroneous sense of familiarity and that familiarity appears to largely depend on the perirhinal region in healthy subjects. In this context, the role of the hippocampus is particularly unclear as it is unknown whether or not it plays a role in the genesis of déjà vu. We report on the case of OHVR, an epileptic patient who suffers from severe episodic amnesia related to massive isolated bilateral damage to the hippocampus. In contrast, the perirhinal region is intact structurally and functionally. This patient reports frequent déjà vu but also another experiential phenomenon with a prominent feeling of prescience, which shows some of the characteristics of déjà vécu. She clearly distinguishes both. She also developed a form of synaesthesia by attributing affective valence to numbers. This study shows that déjà vu can occur in cases of amnesia with massively damaged hippocampi and confirms that the perirhinal region is a core region for déjà vu, using a different approach from previous reports. It also provides clues about a potential influence of hippocampal alterations in déjà vécu. [ABSTRACT FROM AUTHOR]