Lies tell the truth about cognitive dysfunction in essential tremor: an experimental deception study with the guilty knowledge task.

BACKGROUND: Research conducted in the past decade challenges the traditional view that essential tremor (ET) is characterised exclusively by movement disorder, and increasingly shows that these patients have deficits in cognitive and behavioural functioning. The available evidence suggests that this impairment might arise from dysfunction in either the fronto-subcortical or cortico-cerebellar circuits. Although abnormalities in the fronto-subcortical circuits could imply difficulty in lying, no study has investigated deception in patients with ET. AIMS: To examine the cognitive functions regulating deception in patients with ET, we used a computerised task, the Guilty Knowledge Task (GKT). We also tested a group of patients with Parkinson's disease (PD), a disease associated with a known difficulty in lie production, and a group of healthy subjects (HS). RESULTS: In the GKT for deception, patients with ET responded less accurately than HS (p=0.014) but similarly to patients with PD (p=0.955). No differences between groups were found in truthful responses (p=0.488). CONCLUSIONS: Besides confirming impaired deception in patients with PD, our results show a lie production deficit in patients with ET also. These findings suggest that difficulty in lying is an aspecific cognitive feature in movement disorders characterised by fronto-subcortical circuit dysfunction, such as PD and ET. Current knowledge along with our new findings in patients with ET--possibly arising from individually unrecognised extremely mild, cognitive difficulties--should help in designing specific rehabilitative programmes to improve cognitive and behavioural disturbances in patients.

Gender-related differences in moral judgments.

The moral sense is among the most complex aspects of the human mind. Despite substantial evidence confirming gender-related neurobiological and behavioral differences, and psychological research suggesting gender specificities in moral development, whether these differences arise from cultural effects or are innate remains unclear. In this study, we investigated the role of gender, education (general education and health education) and religious belief (Catholic and non-Catholic) on moral choices by testing 50 men and 50 women with a moral judgment task. Whereas we found no differences between the two genders in utilitarian responses to non-moral dilemmas and to impersonal moral dilemmas, men gave significantly more utilitarian answers to personal moral (PM) dilemmas (i.e., those courses of action whose endorsement involves highly emotional decisions). Cultural factors such as education and religion had no effect on performance in the moral judgment task. These findings suggest that the cognitive-emotional processes involved in evaluating PM dilemmas differ in men and in women, possibly reflecting differences in the underlying neural mechanisms. Gender-related determinants of moral behavior may partly explain gender differences in real-life involving power management, economic decision-making, leadership and possibly also aggressive and criminal behaviors.

Lie-specific involvement of dorsolateral prefrontal cortex in deception.

Lies are intentional distortions of event knowledge. No experimental data are available on manipulating lying processes. To address this issue, we stimulated the dorsolateral prefrontal cortex (DLPFC) using transcranial direct current stimulation (tDCS). Fifteen healthy volunteers were tested before and after tDCS (anodal, cathodal, and sham). Two types of truthful (truthful selected: TS; truthful unselected: TU) and deceptive (lie selected: LS; lie unselected: LU) responses were evaluated using a computer-controlled task. Reaction times (RTs) and accuracy were collected and used as dependent variables. In the baseline task, the RT was significantly longer for lie responses than for true responses ([mean +/- standard error] 1153.4 +/- 42.0 ms vs. 1039.6 +/- 36.6 ms; F(1,14) = 27.25, P = 0.00013). At baseline, RT for selected pictures was significantly shorter than RT for unselected pictures (1051.26 +/- 39.0 ms vs. 1141.76 +/- 41.1 ms; F(1,14) = 34.85, P = 0.00004). Whereas after cathodal and sham stimulation, lie responses remained unchanged (cathodal 5.26 +/- 2.7%; sham 5.66 +/- 3.6%), after anodal tDCS, RTs significantly increased but did so only for LS responses (16.86 +/- 5.0%; P = 0.002). These findings show that manipulation of brain function with DLPFC tDCS specifically influences experimental deception and that distinctive neural mechanisms underlie different types of lies.

Improved naming after transcranial direct current stimulation in aphasia.

Transcranial direct current stimulation (tDCS) has been proposed as an adjuvant technique to improve functional recovery after ischaemic stroke. This study evaluated the effect of tDCS over the left frontotemporal areas in eight chronic non-fluent post-stroke aphasic patients. The protocol consisted of the assessment of picture naming (accuracy and response time) before and immediately after anodal or cathodal tDCS (2 mA, 10 minutes) and sham stimulation. Whereas anodal tDCS and sham tDCS failed to induce any changes, cathodal tDCS significantly improved the accuracy of the picture naming task by a mean of 33.6% (SEM 13.8%).

A feasibility study of yarns and fibers with annexed electronic functions: the ARIANNE project.

In this paper several issues concerning the development of fibers endowed with electronic functions will be presented and discussed. In particular, issues concerning materials, structures, electronic models and the mechanical constraints due to textile technologies will be detailed. All these aspects have been studied in the framework of the project ARIANNE, funded by the European Community during the V Frame Programme.

Cerebellar transcranial direct current stimulation impairs the practice-dependent proficiency increase in working memory.

How the cerebellum is involved in the practice and proficiency of non-motor functions is still unclear. We tested whether transcranial direct current stimulation (tDCS) over the cerebellum (cerebellar tDCS) induces after-effects on the practice-dependent increase in the proficiency of a working memory (WM) task (Sternberg test) in 13 healthy subjects. We also assessed the effects of cerebellar tDCS on visual evoked potentials (VEPs) in four subjects and compared the effects of cerebellar tDCS on the Sternberg test with those elicited by tDCS delivered over the prefrontal cortex in five subjects. Our experiments showed that anodal or cathodal tDCS over the cerebellum impaired the practice-dependent improvement in the reaction times in a WM task. Because tDCS delivered over the prefrontal cortex induced an immediate change in the WM task but left the practice-dependent proficiency unchanged, the effects of cerebellar tDCS are structure-specific. Cerebellar tDCS left VEPs unaffected, its effect on the Sternberg task therefore seems unlikely to arise from visual system involvement. In conclusion, tDCS over the cerebellum specifically impairs the practice-dependent proficiency increase in verbal WM.

Transcranial direct current stimulation improves recognition memory in Alzheimer disease.

OBJECTIVE: To evaluate the cognitive effect of transcranial direct current stimulation (tDCS) over the temporoparietal areas in patients with Alzheimer disease (AD). METHODS: In 10 patients with probable AD, we delivered anodal tDCS (AtDCS), cathodal tDCS (CtDCS), and sham tDCS (StDCS) over the temporoparietal areas in three sessions. In each session recognition memory and visual attention were tested at baseline (prestimulation) and 30 minutes after tDCS ended (poststimulation). RESULTS: After AtDCS, accuracy of the word recognition memory task increased (prestimulation: 15.5 +/- 0.9, poststimulation: 17.9 +/- 0.8, p = 0.0068) whereas after CtDCS it decreased (15.8 +/- 0.6 vs 13.2 +/- 0.9, p = 0.011) and after StDCS it remained unchanged (16.3 +/- 0.7 vs 16.0 +/- 1.0, p = 0.75). tDCS left the visual attention-reaction times unchanged. CONCLUSION: Transcranial direct current stimulation (tDCS) delivered over the temporoparietal areas can specifically affect a recognition memory performance in patients with Alzheimer disease (AD). Because tDCS is simple, safe and inexpensive, our finding prompts studies using repeated tDCS, in conjunction with other therapeutic interventions for treating patients with AD.