Our task was similar to directed forgetting designs (Baddeley et al., 2009) when memory for ‘to-be-forgotten’ items is weaker, but regularly above chance level. The above-chance level of performance for distractor letters suggests reliable
responses (i.e. extreme below-chance performance might suggest that participants intentionally did not report distractor letters that they remembered). One may assume that participants simply knew that the distractor will be asked and thus attempted to remember it better and with it they encoded the scenes. However, our results do not indicate that participants attempted to remember the distractor-associated scenes better because scene recognition performance was at the chance level in this condition, which was similar to the case when scenes were presented MG-132 in vivo alone. Moreover, in the dopamine replacement condition, a boosting effect was observed for the recognition of distractor-associated scenes but not for the recall of distractor letters, which indicates an intriguing dissociation between the recall of the central stimulus (letters) and the recognition of the background information (scenes).
A possible explanation may be that the short-term memory systems responsible for maintaining the letters and the neural systems responsible for the attentional boost are not equally affected by PD and dopaminergic medications, and that medicated patients with PD have less control Copanlisib chemical structure over distracting items (e.g. Moustafa et al., 2008). The Tolmetin neuronal correlates of attentional boost and its pharmacological modulation need to be investigated using functional neuroimaging methods. Swallow et al. (2012) provided evidence
that responding to target stimuli at behaviorally relevant points of time enhanced activity in early visual cortical areas, but it is not clear how it affects memory for contextual background images. Although our current results and data from individuals with hippocampal atrophy (Szamosi et al., 2013) suggest the relevance of midbrain dopaminergic–hippocampal interactions in attentional boost (Shohamy & Wagner, 2008; Wimmer et al., 2012), this hypothesis should be directly tested. This study was supported by the National Development Agency (TÁMOP-4.2.2.A-11/1/KONV-2012-0052). Abbreviations ABT attentional boost test ANT attention network test BIS-11 Barratt Impulsiveness Scale-11 HAM-D Hamilton Depression Rating Scale HSD Honestly Significant Difference L-DOPA l-3,4-dihydroxyphenylalanine LED levodopa equivalent dose MIDI Minnesota Impulsive Disorders Interview PD Parkinson’s disease SOGS South Oaks Gambling Screen UPDRS Unified Parkinson’s Disease Rating Scale The authors (S.K., H.N., E.L.G., O.K.) declare no conflict of interest. “
“Several studies have already shown that transcranial direct current stimulation (tDCS) is a useful tool for enhancing recovery in aphasia. However, all tDCS studies have previously investigated the effects using unihemisperic stimulation.