Temporal lobe cortical electrical stimulation during the encoding and retrieval phase reduces false memories

Paulo S Boggio, Felipe Fregni, Claudia Valasek, Sophie Ellwood, Richard Chi, Jason Gallate, Alvaro Pascual-Leone, Allan Snyder, Paulo S Boggio, Felipe Fregni, Claudia Valasek, Sophie Ellwood, Richard Chi, Jason Gallate, Alvaro Pascual-Leone, Allan Snyder

Abstract

A recent study found that false memories were reduced by 36% when low frequency repetitive transcranial magnetic stimulation (rTMS) was applied to the left anterior temporal lobe after the encoding (study) phase. Here we were interested in the consequences on a false memory task of brain stimulation throughout the encoding and retrieval task phases. We used transcranial direct current stimulation (tDCS) because it has been shown to be a useful tool to enhance cognition. Specifically, we examined whether tDCS can induce changes in a task assessing false memories. Based on our preliminary results, three conditions of stimulation were chosen: anodal left/cathodal right anterior temporal lobe (ATL) stimulation ("bilateral stimulation"); anodal left ATL stimulation (with a large contralateral cathodal electrode--referred as "unilateral stimulation") and sham stimulation. Our results showed that false memories were reduced significantly after the two active conditions (unilateral and bilateral stimulation) as compared with sham stimulation. There were no significant changes in veridical memories. Our findings show that false memories are reduced by 73% when anodal tDCS is applied to the anterior temporal lobes throughout the encoding and retrieval stages, suggesting a possible strategy for improving certain aspects of learning.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1. Schematic representation of electrode montages.
Figure 1. Schematic representation of electrode montages.
A represents bilateral stimulation (35 cm2 electrodes in the left and right ATL) and B represents unilateral stimulation (35 cm2 electrode in the left and 100 cm2 electrode in the right ATL).
Figure 2. Performance as indexed by number…
Figure 2. Performance as indexed by number of false memories during sham, unilateral and bilateral stimulation.
Columns represent the mean number of false memories and error bars indicate mean standard error.

References

    1. Bartlett FC. Remembering: A Study in Experimental and Social Psychology. Cambridge, UK: Cambridge University Press; 1932.
    1. Loftus E. Our changeable memories: legal and practical implications. Nat Rev Neurosci. 2003;4:231–234.
    1. Schacter DL, Addis DR. Constructive memory: the ghosts of past and future. Nature. 2007;445:27.
    1. Schacter DL, Addis DR. The cognitive neuroscience of constructive memory: remembering the past and imagining the future. Philos Trans R Soc Lond B Biol Sci. 2007;362:773–786.
    1. Schacter DL, Addis DR, Buckner RL. Episodic simulation of future events: concepts, data, and applications. Ann N Y Acad Sci. 2008;1124:39–60.
    1. Gallate J, Chi R, Ellwood S, Snyder A. Reducing false memories by magnetic pulse stimulation. Neuroscience Letters. 2009;449:151–154.
    1. Brainerd CJ, Reyna VF. Explaining developmental reversals in false memory. Psychol Sci. 2007;18:442–448.
    1. Frith U, Hill EL. Autism: Mind and Brain. Oxford, UK: Oxford University Press; 2003.
    1. Gainotti G. Different patterns of famous people recognition disorders in patients with right and left anterior temporal lesions: a systematic review. Neuropsychologia. 2007;45:1591–1607.
    1. Beversdorf DQ, Smith BW, Crucian GP, Anderson JM, Keillor JM, et al. Increased discrimination of “false memories” in autism spectrum disorder. Proc Natl Acad Sci U S A. 2000;97:8734–8737.
    1. McDermott KB, Ojemann JG, Petersen SE, Ollinger JM, Snyder AZ, et al. Direct comparison of episodic encoding and retrieval of words: an event-related fMRI study. Memory. 1999;7:661–678.
    1. Nitsche M, Cohen L, Wasserman EM, Priori A, Lang N, et al. Transcranial direct current stimulation: State of the art 2008. Brain Stimulation. 2008:206–223.
    1. Wassermann EM, Grafman J. Recharging cognition with DC brain polarization. Trends Cogn Sci. 2005;9:503–505.
    1. Miller BL, Cummings J, Mishkin F, Boone K, Prince F, et al. Emergence of artistic talent in frontotemporal dementia. Neurology. 1998;51:978–982.
    1. Rosso SM, Roks G, Stevens M, de Koning I, Tanghe HLJ, et al. Complex compulsive behaviour in the temporal variant of frontotemporal dementia. J Neurol. 2001;248:965–970.
    1. Mummery CJ, Patterson K, Price CJ, Ashburner J, Frackowiak RS, et al. A voxel-based morphometry study of semantic dementia: relationship between temporal lobe atrophy and semantic memory. Ann Neurol. 2000;47:36–45.
    1. Hou C, Miller BL, Cummings JL, Goldberg M, Mychack P, et al. Autistic savants. [correction of artistic]. Neuropsychiatry Neuropsychol Behav Neurol. 2000;13:29–38.
    1. Kapur N. Paradoxical functional facilitation in brain-behaviour research. A critical review. Brain. 1996;119(Pt 5):1775–1790.
    1. Snyder A, Bossomaier T, Mitchell DJ. Concept formation: ‘object’ attributes dynamically inhibited from conscious awareness. J Integr Neurosci. 2004;3:31–46.
    1. Holliday RE, Weekes BS. Dissociated developmental trajectories for semantic and phonological false memories. Memory. 2006;14:624–636.
    1. Noppeney U, Patterson K, Tyler LK, Moss H, Stamatakis EA, et al. Temporal lobe lesions and semantic impairment: a comparison of herpes simplex virus encephalitis and semantic dementia. Brain. 2007;130:1138–1147.
    1. Olson IR, Plotzker A, Ezzyat Y. The Enigmatic temporal pole: a review of findings on social and emotional processing. Brain. 2007;130:1718–1731.
    1. Thompson SA, Patterson K, Hodges JR. Left/right asymmetry of atrophy in semantic dementia: behavioral-cognitive implications. Neurology. 2003;61:1196–1203.
    1. Nitsche MA, Doemkes S, Karakose T, Antal A, Liebetanz D, et al. Shaping the effects of transcranial direct current stimulation of the human motor cortex. J Neurophysiol. 2007;97:3109–3117.
    1. Gandiga PC, Hummel FC, Cohen LG. Transcranial DC stimulation (tDCS): a tool for double-blind sham-controlled clinical studies in brain stimulation. Clin Neurophysiol. 2006;117:845–850.
    1. Nitsche MA, Paulus W. Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation. J Physiol. 2000;527 Pt 3:633–639.
    1. Iyer MB, Mattu U, Grafman J, Lomarev M, Sato S, et al. Safety and cognitive effect of frontal DC brain polarization in healthy individuals. Neurology. 2005;64:872–875.
    1. Chen R, Classen J, Gerloff C, Celnik P, Wassermann EM, et al. Depression of motor cortex excitability by low-frequency transcranial magnetic stimulation. Neurology. 1997;48:1398–1403.
    1. Fregni F, Marcondes R, Boggio PS, Marcolin MA, Rigonatti SP, et al. Transient tinnitus suppression induced by repetitive transcranial magnetic stimulation and transcranial direct current stimulation. Eur J Neurol. 2006;13:996–1001.
    1. Antal A, Varga ET, Nitsche MA, Chadaide Z, Paulus W, et al. Direct current stimulation over MT+/V5 modulates motion aftereffect in humans. Neuroreport. 2004;15:2491–2494.
    1. Antal A, Nitsche MA, Kruse W, Kincses TZ, Hoffmann KP, et al. Direct current stimulation over V5 enhances visuomotor coordination by improving motion perception in humans. J Cogn Neurosci. 2004;16:521–527.
    1. Pobric G, Mashal N, Faust M, Lavidor M. The role of the right cerebral hemisphere in processing novel metaphoric expressions: a transcranial magnetic stimulation study. J Cogn Neurosci. 2008;20:170–181.
    1. Pobric G, Jefferies E, Ralph MA. Anterior temporal lobes mediate semantic representation: mimicking semantic dementia by using rTMS in normal participants. Proc Natl Acad Sci U S A. 2007;104:20137–20141.

Source: PubMed

Sponsorer og samarbeidspartnere

Medisinsk tilstand

Legemiddelintervensjoner

3
Abonnere