Temporal Lobe Cortical Electrical Stimulation during the Encoding and Retrieval Phase Reduces False Memories

Boggio, Paulo S.; Fregni, Felipe; Valasek, Cláudia Aparecida; Ellwood, Sophie; Po-Hung, Richard; Gallate, Jason; Pascual‐Leone, Álvaro; Snyder, Allan W.

doi:10.1371/journal.pone.0004959

Cited by 95 publications

(84 citation statements)

References 30 publications

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“…In particular, immediate free recalls of the standard list on the 5th and on the 6th trials (the latter after presentation of the IL) were significantly improved by tSOS compared with sham (F 1,11 Ͼ 6.22, P Ͻ 0.03). In light of recent findings (20,21) of effects of transcranial stimulation on the rate of false memories, we analyzed aside from total errors also the number of falsely recalled words (i.e., words not in the standard list), preservation type (repetitions) errors, and accuracy (ratio of total correct words by total cited words), but did not find any differences between the sham and tSOS conditions (each P Ͼ 0.1) ( Table 2; Table S2). Recognition performance on the number list learning task was not sensitive to tSOS (F 1,11 Ͻ 0.74, P Ͼ 0.41) ( Table 2), supporting other studies on differential mechanisms underlying free-recall and recognition (22)(23)(24).…”

Section: Improved Encoding Of Verbal Memory By Tsos Applied During Lementioning

confidence: 78%

“…The application of tSOS during a wake retention interval (i) enhanced frontal EEG slow oscillation activity, but was otherwise associated with distinctly different effects than those observed previously after tSOS during sleep (18); (ii) tSOS during quiet and attentive wakefulness enhanced global activity in the theta (4-8 Hz) frequency band [beta activity (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) was additionally enhanced during quiet wakefulness]; (iii) retention of declarative memories during the wake retention interval was not improved; (iv) instead, tSOS during the process of encoding improved learning performance as assessed by immediate recall of words learned in the presence of stimulation. Our findings indicate that the effects of tSOS on memory function critically depend on the functional brain state (19,25).…”

Section: Discussionmentioning

confidence: 90%

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Slow oscillation electrical brain stimulation during waking promotes EEG theta activity and memory encoding

Kirov

Weiss

Siebner

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

189

170

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The application of transcranial slow oscillation stimulation (tSOS; 0.75 Hz) was previously shown to enhance widespread endogenous EEG slow oscillatory activity when applied during a sleep period characterized by emerging endogenous slow oscillatory activity. Processes of memory consolidation typically occurring during this state of sleep were also enhanced. Here, we show that the same tSOS applied in the waking brain also induced an increase in endogenous EEG slow oscillations (0.4 -1.2 Hz), although in a topographically restricted fashion. Applied during wakefulness tSOS, additionally, resulted in a marked and widespread increase in EEG theta (4 -8 Hz) activity. During wake, tSOS did not enhance consolidation of memories when applied after learning, but improved encoding of hippocampus-dependent memories when applied during learning. We conclude that the EEG frequency and related memory processes induced by tSOS critically depend on brain state. In response to tSOS during wakefulness the brain transposes stimulation by responding preferentially with theta oscillations and facilitated encoding.transcranial slow oscillation stimulation ͉ sleep ͉ plasticity ͉ cortex ͉ tDCS (transcranial direct current stimulation)

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Section: Improved Encoding Of Verbal Memory By Tsos Applied During Lementioning

confidence: 78%

Section: Discussionmentioning

confidence: 90%

Slow oscillation electrical brain stimulation during waking promotes EEG theta activity and memory encoding

Kirov

Weiss

Siebner

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

189

170

View full text Add to dashboard Cite

show abstract

“…Recent studies showed that working memory could be improved by anodal (Fregni et al, 2005;Andrews et al, 2011) or impaired by cathodal stimulation of the DLPFC (Elmer et al, 2009). Boggio et al (2009) demonstrated that recognition memory was subject to modulation as well: anodal tDCS of the anterior temporal cortex throughout the encoding and retrieval phases effectively decreased the rate of false positives in a recognition memory task, while keeping the rate of veridical memories unchanged. The present study demonstrates that tDCS also modulates orbitofrontal reality filtering.…”

Section: Discussionmentioning

confidence: 99%

Frontal tDCS modulates orbitofrontal reality filtering

et al. 2014

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Abstract-Orbitofrontal reality filtering denotes a memory control mechanism necessary to keep thought and behavior in phase with reality. Its failure induces reality confusion as evident in confabulation and disorientation. In the present study, we explored the influence of orbitofrontal transcranial direct current stimulation (tDCS) on reality filtering. Twenty healthy human subjects made a reality filtering task, while receiving cathodal, anodal, or sham stimulation over the frontal pole in three sessions separated by at least 1 week. Computational models predicted that this montage can produce polarity-specific current flow across the posterior medial orbitofrontal cortex (OFC). In agreement with our hypothesis, we found that cathodal tDCS over the frontal pole specifically impaired reality filtering in comparison to anodal and sham stimulation. This study shows that reality filtering, an orbitofrontal function, can be modulated with tDCS. Ó

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“…Previous neuroimaging and patient studies have provided robust evidence that a core network of regions in the medial and lateral temporal lobe, as well as frontal and parietal regions (8)(9)(10)(11)(12)(13)(14)(15)(16), is involved when encoding or retrieving semantic false memories. However, a mechanistic understanding of how these regions generate false memories is lacking.…”

mentioning

confidence: 99%

Semantic representations in the temporal pole predict false memories

Chadwick

Anjum

Kumaran

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Recent advances in neuroscience have given us unprecedented insight into the neural mechanisms of false memory, showing that artificial memories can be inserted into the memory cells of the hippocampus in a way that is indistinguishable from true memories. However, this alone is not enough to explain how false memories can arise naturally in the course of our daily lives. Cognitive psychology has demonstrated that many instances of false memory, both in the laboratory and the real world, can be attributed to semantic interference. Whereas previous studies have found that a diverse set of regions show some involvement in semantic false memory, none have revealed the nature of the semantic representations underpinning the phenomenon. Here we use fMRI with representational similarity analysis to search for a neural code consistent with semantic false memory. We find clear evidence that false memories emerge from a similarity-based neural code in the temporal pole, a region that has been called the "semantic hub" of the brain. We further show that each individual has a partially unique semantic code within the temporal pole, and this unique code can predict idiosyncratic patterns of memory errors. Finally, we show that the same neural code can also predict variation in true-memory performance, consistent with an adaptive perspective on false memory. Taken together, our findings reveal the underlying structure of neural representations of semantic knowledge, and how this semantic structure can both enhance and distort our memories.false memory | semantic | temporal pole | fMRI | pattern similarity E ach of us has a vast store of semantic knowledge that we apply to incoming sensory data to extract meaning from the world around us. Semantic representations are capable of capturing important structural features of the world at many different levels of abstraction, which allows for rapid and flexible responses to a diverse array of environmental challenges. This preexisting knowledge structure guides ongoing cognition, which usually aids performance, but under some circumstances can lead us into error (1-3). A striking example is the widely studied DRM (Deese, Roediger, and McDermott) false-memory illusion (4, 5). In a typical DRM task, subjects are asked to memorize a set of words such as "snow," "winter," "ice," and "warm." After a delay, subjects will typically falsely remember having seen the semantically related word "cold." It is widely agreed that this memory illusion is driven by the semantic relatedness between words contained in the encoding list (e.g., "snow") and falsely remembered words that were not actually presented (e.g., "cold"). As such, it is thought that each list item automatically, but weakly, activates the semantically related concept (Fig. 1A). This activation leads to memory confusion, either through a cumulative priming of the related lure (5, 6) or the encoding of the semantic overlap as a "gist" memory (3), resulting in a false memory unless the error is detected by some internal monitoring p...

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Temporal Lobe Cortical Electrical Stimulation during the Encoding and Retrieval Phase Reduces False Memories

Cited by 95 publications

References 30 publications

Slow oscillation electrical brain stimulation during waking promotes EEG theta activity and memory encoding

Slow oscillation electrical brain stimulation during waking promotes EEG theta activity and memory encoding

Frontal tDCS modulates orbitofrontal reality filtering

Semantic representations in the temporal pole predict false memories

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