The implications of state-dependent tDCS effects in aging: behavioural response is determined by baseline performance

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Learmonth, Gemma ; Thut, Gregor ; Benwell, Christopher S.Y. ; Harvey, Monika (2015)
  • Publisher: Elsevier
  • Journal: Neuropsychologia (issn: 0028-3932, vol: 74, pp: 108-119)
  • Related identifiers: doi: 10.1016/j.neuropsychologia.2015.01.037
  • Subject: Experimental and Cognitive Psychology | Behavioral Neuroscience | Cognitive Neuroscience
    mesheuropmc: genetic structures

Young adults typically display a processing advantage towards the left side of space (“pseudoneglect”), possibly as a result of right parietal dominance for spatial attention. This bias is ameliorated with age, with older adults displaying either no strongly lateralised bias, or a slight bias towards the right. This may represent an age-related reduction of right hemispheric dominance and/or increased left hemispheric involvement. Here, we applied anodal transcranial direct current stimulation (atDCS) to the right posterior parietal cortex (PPC; R-atDCS), the left PPC (L-atDCS) and a Sham protocol in young and older adults during a titrated lateralised visual detection task. We aimed to facilitate visual detection sensitivity in the contralateral visual field with both R-atDCS and L-atDCS relative to Sham. We found no differences in the effects of stimulation between young and older adults. Instead the effects of atDCS were state-dependent (i.e. related to task performance at baseline). Relative to Sham, poor task performers were impaired in both visual fields by anodal stimulation of the left posterior parietal cortex (PPC). Conversely, good performers maintained sensitivity in both visual fields in response to R-atDCS, although this effect was small. We highlight the importance of considering baseline task ability when designing tDCS experiments, particularly in older adults.
  • References (118)
    118 references, page 1 of 12

    Antal, A., Terney, D., Poreisz, C., Paulus, W., 2007. Towards unravelling task-related modulations of neuroplastic changes induced in the human motor cortex. Eur. J. Neurosci. 26 (9), 2687-2691.

    Bäckman, L., Almkvist, O., Andersson, J., Nordberg, A., Winblad, B., Reineck, R., 1997. Brain activation in young and older adults during implicit and explicit retrieval. J. Cogn. Neurosci. 9, 378-391.

    Benwell, C.S.Y., Learmonth, G., Miniussi, C., Harvey, M., Thut, G., 2015. State-dependency in transcranial direct current stimulation: a role for stochastic resonance? Cortex (submitted for publication).

    Benwell, C.S.Y., Harvey, M., Gardner, S., Thut, G., 2013a. Stimulus- and state-dependence of systematic bias in spatial attention: additive effects of stimulussize and time-on-task. Cortex 49 (3), 827-836. cortex.2011.12.007.

    Benwell, C.S.Y., Learmonth, G., Thut, G., Harvey, M., 2013b. Spatial attention: differential shifts in pseudoneglect direction with time-on-task and initial bias support the idea of observer subtypes. Neuropsychologia 51, 2747-2756. http: //

    Benwell, C.S.Y., Thut, G., Grant, A., Harvey, M., 2014. A rightward shift in the visuospatial attention vector with healthy aging. Front. Aging Neurosci. 6 (113), 1-11.

    Berryhill, M.E., Jones, K.T., 2012. tDCS selectively improves working memory in older adults with more education. Neurosci. Lett. 521 (2), 148-151. http://dx.

    Bisiach, E., Vallar, G., 2000. Unilateral neglect in humans. In: Boller, F., Grafman, J., Rizzolatti, G. (Eds.), Handbook of Neuropsychology, 2nd ed. Elsevier Science, Amsterdam.

    Borgo, M., Soranzo, A., Grassi, M., 2012. MATLAB for Psychologists. Springer, New York.

    Bowers, D., Heilman, K.M., 1980. Pseudoneglect: effects of hemispace on a tactile line bisection task. Neuropsychologia 18 (4-5), 491-498. 10.1016/0028-3932(80)90151-7.

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