Déjà vu and involuntary autobiographical memories as two distinct cases of familiarity in patients with Alzheimer's disease.

The continuum between involuntary autobiographical memories and déjà vu, as proposed by Barzykowski and Moulin, can be better defined by considering research on autobiographical retrieval in patients with Alzheimer's disease. Although autobiographical retrieval in patients with Alzheimer's disease can generally be associated with a sense of familiarity, involuntary retrieval can trigger an autonoetic experience of retrieval in these patients.

A spontaneous neural replay account for involuntary autobiographical memories and déjà vu experiences.

Barzykowski and Moulin argue both involuntary autobiographical memories and déjà vu experiences rely on the same involuntary memory retrieval processes but their underlying neurological basis remains unclear. We propose spontaneous neural replay in the default mode network (DMN) and hippocampus as the basis for involuntary autobiographical memories, whereas for déjà vu experiences such transient activation is limited to the DMN.

Does inhibitory (dys)function account for involuntary autobiographical memory and déjà vu experience?

External cues and internal configuration states are the likely instigators of involuntary autobiographical memories (IAMs) and déjà vu experience. Indeed, Barzykowski and Moulin discuss relevant neuroscientific evidence in this direction. A complementary line of enquiry and evidence is the study of inhibition and its role in memory retrieval, and particularly how its (dys)function may contribute to IAMs and déjà vu.

The need for a unified framework: How Tulving's framework of memory systems, memory processes, and the SPI-model can guide and sharpen the understanding of déjà vu and involuntary autobiographical memories and add to conceptual clarity.

Barzykowski and Moulin link déjà vu and involuntary autobiographical memories to the process of retrieval. They make no reference to Tulving's SPI-model. In this, it is proposed that information is acquired serially (S), stored in parallel (P), and retrieved independently (I). This model offers an alternative, elegant, view of involuntary autobiographical memory retrieval, as well as of déjà vus.

Involuntary memory signals in the medial temporal lobe.

We highlight recent progress in neuroimaging and neuropsychological research on memory mechanisms in the medial temporal lobe that speaks to the involuntary nature of memory retrieval processes. We suggest that evidence form these studies supports Barzykowski and Moulin's proposal that memory signals involved in experiences of familiarity and déjà vu can be generated in the absence of retrieval intentionality.

Are involuntary autobiographical memory and déjà vu cognitive failures?

This commentary supports Barzykowski and Moulin's model, but departs from it on the question of functionality, where IAMs and déjà vu fractionate. The authors seem to say that IAMs are functional, while déjà vu is not. As there is no hard evidence supporting the idea that IAMs are functional, I argue that both phenomena should be viewed as cognitive failures.

The misidentification syndromes and source memory deficits with their neuroanatomical correlates from neuropsychological perspective.

The suggested model is discussed with reference to two clinical populations with memory disorders - patients with misidentification syndromes and those with source memory impairment, both of whom may present with (broadly conceived) déjà vu phenomenon, without insight into false feeling of familiarity. The role of the anterior thalamic nucleus and retrosplenial cortex for autobiographical memory and familiarity is highlighted.

The relation of subjective experience to cognitive processing.

Barzykowski and Moulin argue that common memory processes form the basis of involuntary autobiographical memory and the déjà vu experience. We think that they underemphasize the potential dissociability between processes that enact retrieval and the processes that produce conscious experience. We propose that retrieval and conscious experience result from different processes in both involuntary autobiographical memory and déjà vu experiences.

Intracranial electrical brain stimulation as an approach to studying the (dis)continuum of memory experiential phenomena.

Déjà vu and involuntary autobiographical memories (IAM) can be induced by intracranial electric brain stimulation in epileptic patients, sometimes in the same individual. We suggest that there may be different types of IAM which should be taken into account and provide several ideas to test the hypothesis of a continuity between IAM and déjà vu phenomena.

On the frequency and nature of the cues that elicit déjà vu and involuntary autobiographical memories.

Barzykowski and Moulin suggest that déjà vu and involuntary autobiographical memories recruit similar retrieval processes. Here, we invite the authors to clarify three issues: (1) What mechanism prevents déjà vu to happen more frequently? (2) What is the role of semantic cues in involuntary autobiographical retrieval? and (3) How déjà vu relates to non-believed memories?

What do we gain (or lose) by considering déjà vu a part of autobiographical memory?

I argue the relationship between déjà vu and autobiographical memory is not continuous, but more akin to a path diagram. The starting points might be overlapping, but eventually the paths diverge dependent on whether there is memory content to be retrieved. I am worried that considering déjà vu as part of autobiographical memory solves more problems than it creates.

Oh it's me again: Déjà vu, the brain, and self-awareness.

Déjà vu and involuntary autobiographical memories (IAMs) are differentiated by a number of factors including metacognition. In contrast to IAMs, déjà vu activates regions associated with self-awareness including the right dorsolateral prefrontal cortex.

Evolutionary mismatch and anomalies in the memory system.

In order to understand involuntary autobiographical memories and déjà vu experiences, we argue that it is important to take an evolutionary medicine perspective. Here, we propose that these memory anomalies can be understood as the outcomes of an inevitable design trade-off between type I and type II errors in memory processing.

Distinguishing involuntary autobiographical memories and déjà vu experiences: Different types of cues and memory representations?

Although involuntary autobiographical memories (IAMs) and déjà vu have important shared characteristics, in this commentary, we focus on potential differences that may question the argument that two phenomena lie on a continuum. We propose that differences in their frequency and autonoetic consciousness could be explained by different types of cues and memory representations involved in experiencing IAMs and déjà vu.

Association of Deja vu With Cardiovascular Diseases.

Recent studies have suggested a link between déjà vu and cardiovascular diseases (CVDs). While the mechanism for this association is not fully understood, 1 theory suggests that déjà vu may be a result of a disruption in the temporal lobe, which is also responsible for regulating blood pressure and heart rate. Another theory suggests that there may be a shared genetic factor between the 2 conditions, with certain individuals being predisposed to experiencing both. The Apolipoprotein E (APOE) gene, in particular, has been associated with memory processing, Alzheimer's disease, and an increased risk of CVD. The protein encoded by this gene is involved in the metabolism of lipoproteins, including cholesterol and triglycerides, and is also involved in the development of atherosclerosis, which is a key risk factor for CVD. Several hypotheses have been proposed to explain how the APOE4 isoform contributes to CVD, including impairing the clearance of lipoproteins, promoting inflammation, and causing endothelial dysfunction. Psychological factors such as stress may also contribute to the development of CVD, and déjà vu may be associated with emotional arousal and stress. Further research is needed to fully understand the link between déjà vu and CVDs and to explore potential treatment options for individuals who experience both conditions.

Are involuntary autobiographical memory and déjà vu natural products of memory retrieval?

Involuntary autobiographical memories (IAMs) and déjà vu are phenomena that occur spontaneously in daily life. IAMs are recollections of the personal past, whereas déjà vu is defined as an experience in which the person feels familiarity at the same time as knowing that the familiarity is false. We present and discuss the idea that both IAMs and déjà vu can be explained as natural phenomena resulting from memory processing and, importantly, are both based on the same memory retrieval processes. Briefly, we hypothesise that both can be described as "involuntary" or spontaneous cognitions, where IAMs deliver content and déjà vu delivers only the feeling of retrieval. We map out the similarities and differences between the two, making a theoretical and neuroscientific account for their integration into models of memory retrieval and how the autobiographical memory literature can explain these quirks of daily life and unusual but meaningful phenomena. We explain the emergence of the déjà vu phenomenon by relating it to well-known mechanisms of autobiographical memory retrieval, concluding that IAMs and déjà vu lie on a continuum.

Déjà-vu evoked by electrical stimulation of the insula.

OBJECTIVE: Déjà-vu is a mental phenomenon commonly experienced during temporal lobe seizures and can be evoked by electrical stimulation of the temporal lobe. We analyzed reproducible déjà-vu experiences evoked by stimulating the insula in two patients with pharmacoresistant temporal lobe epilepsy. METHODS: We reviewed video-electroencephalography (EEG) recordings from extraoperative electrical cortical stimulation sessions. In addition, we performed the directed transfer function (DTF) effective connectivity measure of monopolar signals in Patient 1. To highlight elective changes due to each stimulation, we subtracted pre-stimulation DTF matrices from early poststimulation matrices. This analysis was performed for both non-inducing-déjàvu stimulation (control matrix) and déjà-vu-inducing stimulation (active matrix). Finally, the control matrix was subtracted from the active matrix. RESULTS: Comparison of effective connectivity during control stimulation versus déjà-vu-inducing stimulation revealed a reversal of connectivity levels in three main regions: the contralateral inferior insula (the ipsilateral insula could not be analyzed), bilateral mesiotemporal regions and the ipsilateral superior frontal gyrus. The drivers of evoked déjà-vu were the mesiotemporal regions (mainly ipsilateral) and the ipsilateral superior frontal gyrus. SIGNIFICANCE: Although our findings are possibly anecdotal, the insula may (in rare instances) remotely generate unexpected déjà-vu. If confirmed by further studies, this might change the assessment strategy for possible causes of anterior temporal lobectomy failure.

What déjà vu and the "dreamy state" tell us about episodic memory networks.

Illusions of inappropriate familiarity with the current experience or hallucinatory recall of memories are reported in temporal lobe seizures. Pathophysiological hypotheses have been proposed, involving temporal limbic regions (Hughlings-Jackson), temporal neocortex ("interpretive cortex", Penfield), or both (Bancaud). Recent data acquired from presurgical investigations using intracerebral electrode recordings, demonstrate a critical role for the sub- and para-hippocampal cortices. From this, a novel hypothesis of cortico-limbic networks emerged: déjà-vu results from an abnormal synchronization between rhinal cortices and hippocampus, and reminiscences ("dreamy state") from activation of the associational function of the hippocampus in re-assembling elements of the past experience networks. "Experiential" phenomena are better scrutinized during direct cortical stimulation than during spontaneous occurrence, because it allows precise spatiotemporal correlations to be made between the illusion/hallucination and the electrical discharge features and localization. Therefore, we present a summary of the stimulation data published since Penfield's seminal studies, review the anatomical and physiological correlations of stimulation findings, and question their functional significance. We reappraise the distinct and coactive roles of the various regions involved in perception-memory processes including the hippocampus, rhinal cortices, temporal neocortex and constituent elements of the ventral stream. Additionally, we draw insights from what is known about the perception-cognition continuum underlying the construction of episodic memories. Finally, we compare the results from cortical stimulation in the epileptogenic zone with the use of stimulation for memory enhancement and explore what this reveals about the mechanisms of stimulation.