We propose that IAM and déjà vu may not share a placement on the same gradient, per se, but the mechanism of cue familiarity detection, and a major differentiating factor between the two metacognitive experiences is whether the resulting inward directed search of memory yields retrieved content or not. Déjà vu may manifest when contentless familiarity detection is inexplicable by the experiencer.

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.

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.

The proposed framework can benefit from integrating predictive processing into the explanation of déjà vu which corresponds to interrupted prediction. Déjà vu is also accompanied by familiarity. However, considerable ambiguity is inherent in familiarity, which necessitates elaboration of this construct. Research findings on involuntary autobiographical memories and déjà vu show discrepancies, and clustering these constructs can be counterproductive for research.

Dementia syndromes offer a unique opportunity to clarify some of the component processes of spontaneous expressions of memory proposed by the Barzykowski and Moulin model. By considering the model through the lens of memory disorders, I outline several important extensions to progress our understanding of these spontaneous cognitive phenomena.

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.

The proposed memory architecture by Barzykowski and Moulin is compelling, and could be improved by incorporating a rational analysis of the functional roles of involuntary autobiographical memory and déjà vu. Additionally, modeling these phenomena computationally would remove ambiguities from the proposal. We provide examples of past work that illustrate how the phenomena may be described more precisely.

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.

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.

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?

On Barzykowski and Moulin's continuum hypothesis, déjà vu and involuntary autobiographical memories (IAMs) share their underpinning neurocognitive processes. A discontinuity issue for them is that familiarity and episodic recollection exhibit different neurocognitive signatures. This issue can be overcome, I say, provided the authors are ready to distinguish a déjà vécu/episodic IAM continuity and a déjà vu/semantic IAM continuity.

Barzykowski and Moulin's model proposes that déjà vu and involuntary autobiographical memories are the result of a continuously active memory system that tracks the novelty of situations. Déjà vu would only have episodic content and concern interpretation of prior experiences. We argue that these aspects of the model would gain to be clarified and explored further and we suggest possible directions.

We raise two points about cues, which complicate Barzykowski and Moulin's attempt at a unified model of memory retrieval. First, cues operate differently in voluntary and involuntary contexts. Second, voluntary and involuntary memory can be interconnected, as in cases of chaining.

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.

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.

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.

Rather than a natural product, a computational analysis leads us to characterize déjà vu as a failure of memory retrieval, linked to the activation in neocortex of familiar items from a compositional memory in the absence of hippocampal input, and to a misappropriation by the self of what is of others.

The target article claims that involuntary autobiographical memories and déjà vu are based on the same retrieval processes, although they result in different phenomenological states. Here we argue that the differential engagement of attention at various stages of memory may be one of the determinants of when common retrieval processes give rise to such different 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.