***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE Because neuroimaging studies have shown that cue-provoked smoking craving is associated with changes in the activity of the bilateral dorsolateral prefrontal cortex ( DLPFC ) , we aim ed to investigate whether a powerful technique of noninvasive brain stimulation , transcranial direct current stimulation ( tDCS ) , reduces cue-provoked smoking craving as indexed by a visual analog scale . METHOD We performed a r and omized , sham-controlled crossover study in which 24 subjects received sham and active tDCS ( anodal tDCS of the left and right DLPFC ) in a r and omized order . Craving was induced by cigarette manipulation and exposure to a smoking video . The study ran from January 2006 to October 2006 . RESULTS Smoking craving was significantly increased after exposure to smoking-craving cues ( p < .0001 ) . Stimulation of both left and right DLPFC with active , but not sham , tDCS reduced craving significantly when comparing craving at baseline and after stimulation , without ( p = .007 ) and with ( p = .005 ) smoking-craving cues . There were no significant mood changes in any of the conditions of stimulation . Adverse events were mild and distributed equally across all treatment conditions . CONCLUSIONS Our findings extend the results of a previous study on the use of brain stimulation to reduce craving , showing that cortical stimulation with tDCS is beneficial for reducing cue-provoked craving , and thus support the further exploration of this technique for smoking cessation BACKGROUND Functional neuroimaging studies have shown that specific brain areas are associated with alcohol craving including the dorsolateral prefrontal cortex ( DLPFC ) . We tested whether modulation of DLPFC using transcranial direct current stimulation ( tDCS ) could alter alcohol craving in patients with alcohol dependence while being exposed to alcohol cues . METHODS We performed a r and omized sham-controlled study in which 13 subjects received sham and active bilateral tDCS delivered to DLPFC ( anodal left/cathodal right and anodal right/cathodal left ) . For sham stimulation , the electrodes were placed at the same positions as in active stimulation ; however , the stimulator was turned off after 30s of stimulation . Subjects were presented videos depicting alcohol consumption to increase alcohol craving . RESULTS Our results showed that both anodal left/cathodal right and anodal right/cathodal left significantly decreased alcohol craving compared to sham stimulation ( p<0.0001 ) . In addition , we found that following treatment , craving could not be further increased by alcohol cues . CONCLUSIONS Our findings showed that tDCS treatment to DLPFC can reduce alcohol craving . These findings extend the results of previous studies using noninvasive brain stimulation to reduce craving in humans . Given the relatively rapid suppressive effect of tDCS and the highly fluctuating nature of alcohol craving , this technique may prove to be a valuable treatment strategy within the clinical setting We aim ed to assess whether modulation of the dorsolateral prefrontal cortex ( DLFPC ) with noninvasive brain stimulation , namely transcranial direct current stimulation ( tDCS ) , modifies  food craving in healthy subjects . We performed a r and omized sham-controlled cross-over study in which 23 subjects received sham and active tDCS  ( anode left/cathode right and anode right/cathode left ) of the DLPFC . Subjects were exposed to food and also watched a movie of food associated with strong craving . Desire for food consumption was evaluated by visual analogue scales ( VAS ) and food consumption before and after treatment . In addition we measured visual attention to food using an eye tracking system . Craving for viewed foods as indexed by VAS was reduced by anode right/cathode left tDCS . After sham stimulation , exposure to real food or food-related movie increased craving ; whereas after anode left/cathode right tDCS , the food-related stimuli did not increase craving levels , as revealed by the VAS scale . Moreover , compared with sham stimulation , subjects fixated food-related pictures less frequently after anode right/cathode left tDCS and consumed less food after both active stimulation conditions . These changes were not related to mood changes after any type of tDCS treatment . The effects of tDCS on food craving might be related to a modulation of neural circuits associated with reward and decision-making Drug-related cues induce craving , which may perpetuate drug use or trigger relapse in addicted individuals .  Craving is also under the influence of other factors in daily life , such as drug availability and self-control . Neuroimaging studies using drug cue paradigms have shown frontal lobe involvement in this context ual influence on cue reactivity , but have not clarified how and which frontal area accounts for this phenomenon . We explored frontal lobe contributions to cue-induced drug craving under different intertemporal drug availability conditions by combining transcranial magnetic stimulation and functional magnetic resonance imaging in smokers . We hypothesized that the dorsolateral prefrontal cortex ( DLPFC ) regulates craving during changes in intertemporal availability . Subjective craving was greater when cigarettes were immediately available , and this effect was eliminated by transiently inactivating the DLPFC with transcranial magnetic stimulation . Functional magnetic resonance imaging demonstrated that the signal most proportional to subjective craving was located in the medial orbitofrontal cortex across all context s , whereas the DLPFC most strongly encoded intertemporal availability information . The craving-related signal in the medial orbitofrontal cortex was attenuated by inactivation of the DLPFC , particularly when cigarettes were immediately available . Inactivation of the DLPFC also reduced craving-related signals in the anterior cingulate and ventral striatum , areas implicated in transforming value signals into action . These findings indicate that DLPFC builds up value signals based on knowledge of drug availability , and support a model wherein aberrant circuitry linking dorsolateral prefrontal and orbitofrontal cortices may underlie addiction BACKGROUND Modulation of the serotonergic system affects long-term potentiation ( LTP ) and long-term depression ( LTD ) , the likely neurophysiologic derivates of learning and memory formation , in animals and slice preparations . Serotonin-dependent modulation of plasticity has been proposed as an underlying mechanism for depression . However , direct knowledge about the impact of serotonin on neuroplasticity in humans is missing . Here we explore the impact of the serotonin reuptake blocker citalopram on plasticity induced by transcranial direct current stimulation ( tDCS ) in humans in a single-blinded , placebo-controlled , r and omized crossover study . METHODS In 12 healthy subjects , anodal excitability-enhancing or cathodal excitability-diminishing tDCS was applied to the motor cortex under a single dose of 20-mg citalopram or placebo medication .  Motor cortex excitability was monitored by single-pulse transcranial magnetic stimulation ( TMS ) . RESULTS Under placebo medication , anodal tDCS enhanced , and cathodal tDCS reduced , excitability for about 60 - 120 min . Citalopram enhanced and prolonged the facilitation induced by anodal tDCS , whereas it turned cathodal tDCS-induced inhibition into facilitation . CONCLUSIONS Serotonin has a prominent impact on neuroplasticity in humans , which is in favor for facilitatory plasticity . Taking into account serotonergic hypoactivity in depression , this might explain deficits of learning and memory formation . Moreover , the results suggest that for therapeutic brain stimulation in depression and other neuropsychiatric diseases ( e.g. , in neurorehabilitation ) , serotonergic reinforcement may enhance facilitatory aftereffects and thereby increase the efficacy of these tools Food craving can be defined as the " urge to eat a specific food " . Previous findings suggest impairment of inhibitory control , specifically a regulatory deficit in the lateral prefrontal circuitry that is associated with a compulsion for food . As demonstrated by three previous studies , bilateral transcranial direct current stimulation ( tDCS ) of the dorsolateral prefrontal cortex ( DLPFC ) ( anode right/cathode left ) reduces food craving and caloric intake . We design ed the present study to evaluate the neural mechanisms that underlie these effects . We replicated the design of one of these previous studies but included  electroencephalographic assessment s to register evoked potentials in a Go/No-go task that contained pictures of food and furniture ( a control visual stimulus ) . We collected data from nine women ( mean age = 23.4 ± 2 years ) in a crossover experiment . We observed that active DLPFC tDCS ( anode right/cathode left ) , compared with sham stimulation , reduced the frontal N2 component and enhanced the P3a component of responses to No-go stimuli , regardless of the stimulus condition ( food or furniture ) . Active tDCS was also associated with a reduction in caloric intake . We discuss our findings in the context of cortico-subcortical processing of craving and tDCS effects on inhibitory control neural circuitry Bulimia nervosa , binge-eating disorder , and some forms of obesity are characterised by compulsive overeating that is often precipitated by food craving . Transcranial direct current stimulation ( tDCS ) has been used to suppress food cravings , but there is insufficient evidence to support its application in clinical practice . Furthermore , the potential moderating role of impulsivity has not been considered . This study used a r and omised within-subjects crossover design to examine whether a 20-minute session of sham-controlled bilateral tDCS to the dorsolateral prefrontal cortex ( anode right/cathode left ) would transiently modify food cravings and temporal discounting ( TD ; a measure of choice impulsivity ) in 17 healthy women with frequent food cravings . Whether the effects of tDCS on food craving were moderated by individual differences in TD behaviour was also explored . Participants were exposed to food and a film of people eating , and food cravings and TD were assessed before and after active and sham stimulation .  Craving for sweet but not savoury foods was reduced following real tDCS . Participants that exhibited more reflective choice behaviour were more susceptible to the anti-craving effects of tDCS than those that displayed more impulsive choice behaviour . No differences were seen in TD or food consumption after real versus sham tDCS . These findings support the efficacy of tDCS in temporarily lowering food cravings and identify the moderating role of TD behaviour Study ing social behavior often requires the simultaneous interaction of many subjects . As yet , however , no painless , noninvasive brain stimulation tool existed that allowed the simultaneous affection of brain processes in many interacting subjects . Here we show that transcranial direct current stimulation ( tDCS ) can overcome these limits . We apply right prefrontal cathodal tDCS and show that subjects '  propensity to punish unfair behavior is reduced significantly BACKGROUND The dorsolateral prefrontal cortex ( DLPFC ) plays an important role in appetite and food intake regulation . OBJECTIVE Because previous data revealed that transcranial direct current stimulation ( tDCS ) of the DLPFC reduces food cravings , we hypothesized that repetitive electric stimulation of the right DLPFC would lower food intake behavior in humans . DESIGN In a single-blind , code-based , placebo-controlled , counterbalanced , r and omized crossover experiment , 14 healthy young men with body mass index ( in kg/m(2 ) ) from 20 to 25 were examined during 8 d of daily tDCS or a sham stimulation . After tDCS or sham stimulation on the first and the last day of both experimental conditions , participants consumed food ad libitum from a st and ardized test buffet . RESULTS One week of daily anodal tDCS reduced overall caloric intake by 14 % in comparison with sham stimulation . Moreover , repetitive tDCS diminished self-reported appetite scores . CONCLUSION Our study implies that the application of anodal direct currents to the right DLPFC represents a promising option for reducing both caloric intake and appetite in humans . This trial was registered at the German Clinical Trials Register ( www.germanctr.de ) as DRKS00005811 OBJECTIVE Brain polarization in the form of transcranial direct current stimulation ( tDCS ) , which influences motor function and learning processes , has been proposed as an adjuvant strategy to enhance training effects in Neurorehabilitation . Proper testing in Neurorehabilitation requires double-blind sham-controlled study design s. Here , we evaluated the effects of tDCS and sham stimulation ( SHAM ) on healthy subjects and stroke patients ' self-report measures of attention , fatigue , duration of elicited sensations and discomfort . METHODS tDCS or SHAM was in all cases applied over the motor cortex . Attention , fatigue , and discomfort were self rated by study participants using visual analog scales . Duration of perceived sensations and the ability to distinguish tDCS from Sham sessions were determined . Investigators question ing the patients were blind to the intervention type . RESULTS tDCS and SHAM elicited comparably minimal discomfort and duration of sensations in the absence of differences in attention or fatigue , and could not be distinguished from SHAM by study participants nor investigators . CONCLUSIONS Successful blinding of subjects and investigators and ease of application simultaneously with training protocol s supports the feasibility of using tDCS in double-blind , sham-controlled r and omized trials in clinical Neurorehabilitation . SIGNIFICANCE tDCS could evolve into a useful tool , in addition to TMS , to modulate cortical activity in Neurorehabilitation This study examined whether a 20-min session of prefrontal transcran 
    Output:
    
So far focusing essentially on abnormal eating , these studies suggest that tDCS ( right prefrontal anode/left prefrontal cathode ) reduces food craving induced by visual stimuli .
Conclusions : Despite method ological and technical differences between studies , the results are promising .