Brain stimulation techniques in the treatment of obsessive-compulsive disorder: current and future directions

Recent studies on the epidemiology of obsessive-compulsive disorder (OCD) estimate 50 million patients suffer from OCD worldwide, thus making it a global problem. The treatment of OCD has changed substantially over the last 2 decades following the introduction of selective serotonin reuptake inhibitors, which provide symptom improvement in approximately 60% of patients. However, some patients remain resistant to the standard pharmacologic and behavioral treatments. Although some treatment-resistant patients respond to pharmacologic augmentations, others do not, and there is evidence that some of the most severe cases benefit from treatment with neurosurgical interventions. Besides pharmacologic, behavioral, and neurosurgical approaches, different brain stimulation methods-transcranial magnetic stimulation, deep brain stimulation, and electroconvulsive therapy-have been investigated in treatment-resistant patients with OCD. However, available data about the use of these techniques in OCD treatment are quite limited in terms of sample size and study design, given the difficulty in conducting standard blinded trials for these procedures. In addition, none of the mentioned treatments have received Food and Drug Administration approval for the treatment of OCD. Nevertheless, promising findings regarding efficacy, tolerability, and non-invasiveness and/or reversibility of these techniques have increased interest in investigating their use in treatment-resistant OCD.     

Detection of grouped and ungrouped parts in visual patterns by tufted capuchin monkeys (Cebus apella) and humans (Homo sapiens)

The authors investigated perceptual grouping in capuchin monkeys (Cebus apella) and humans (Homo sapiens). In Experiment 1, 6 monkeys received a visual pattern as the sample and had to identify the comparison stimulus featuring some of its parts. Performance was better for ungrouped parts than for grouped parts. In Experiment 2, the sample featured the parts, and the comparison stimuli, the complex figures: The advantage for ungrouped elements disappeared. In Experiment 3, in which new stimuli were introduced, the results of the previous experiments were replicated. In Experiment 4, 128 humans were presented with the same tasks and stimuli used with monkeys. Their accuracy was higher for grouped parts. Results suggest that human and nonhuman primates use different modes of analyzing multicomponent patterns.     

Processing of irrelevant location information under dual-task conditions

This study deals with the problem of whether the processing of irrelevant location information in Simon-like tasks is triggered exogenously or endogenously. In Experiment 1, the primary task required one to press, as fast as possible, a left-hand-side key or a right-hand-side key (R1) to the pitch of a tone that was presented binaurally (S1). The secondary task required identifying, without time constraints, a visual stimulus (S2) that appeared randomly to the left or right of screen center. Results showed that there was a correspondence (i.e., a cross-task Simon effect) between the location of R1 and the location of S2 when S2 was presented alone. The cross-task Simon effect became much smaller (and in-significant) when a noise stimulus was presented contralateral to S2. Experiment 2 was similar to Experiment 1, except that S2 appeared unpredictably in only one-third of the trials. Results of Experiment 2 closely replicated those of Experiment 1: the cross-task Simon effect was much greater when S2 was presented alone. Experiment 3 differed from Experiment 1 because S2 had to be processed in only one-third of the trials, in which its identity was to be reported. In the remaining two-thirds of the trials, participants could ignore S2. Results confirmed that the cross-task Simon effect was much greater when S2 was presented alone. In contrast, it did not matter whether S2 had to be processed or not. In conclusion, the present study supports the hypothesis that the task-irrelevant spatial code of the stimulus is formed automatically, likely through an exogenously triggered selection. The role of endogenously initiated selection, if any, is much less important.     

The role of affordances in inhibition of return

Inhibition of return (IOR) is a response delay that occurs when the target is preceded by an irrelevant stimulus (cue) at the same location. IOR can be object based, as well as location based. The aim of the present study was to investigate the role of the pragmatic features of a visually presented object in causing IOR. Two experiments were carried out using different objects as stimuli, for which the graspable part (affordance) was clearly defined. The presentation of a whole object, with the part commonly used to grasp it located below, served as a cue. The presentation of either the graspable or the ungraspable part of the cued or uncued object served as the target Results showed that responses were slower when the graspable part was shown in the cued location than when the ungraspable part was shown in the same location. The effect was apparently linked to the kind of action necessary to grasp an object.     

Music and physical activity in psychological well-being

The present study was designed to examine the effects of listening to music during exercise of moderate intensity on mood, state anxiety, and time to exhaustion as well as to evaluate sex differences in 27 physically active (14 men, 13 women) subjects between the ages of 20 and 30 years. Participants completed the Profile of Mood States and the State Anxiety Inventory before and after treadmill running in Music and No music conditions. Music and No Music conditions were randomly assigned, and participants exercised at 75% of their Heart Rate Reserve until voluntary exhaustion. Analysis indicated participants reported statistically significant mean changes on Tension, Depression, Fatigue, Confusion, and State Anxiety. However, the findings for emotions yielded no significant effect of music, except findings suggested that women, but not men, reported greater mean Fatigue after exercising in the presence of music than in its absence. Also, there was a statistically significant finding suggesting that women exercised longer with music than without.     

Inhibitory and facilitatory effects of cue onset and offset

The response speed to a visual target is modulated by the position of previous events (cues) even if their position is not predictive of the target position. The modulation has been considered biphasic, with an early facilitatory and a later inhibitory component. We conducted three experiments that investigated the importance of the onset and offset features of the cue for the facilitatory and inhibitory effects and estimated their separate and joint effects. The two possible target locations, one in the right and one in the left visual field, were indicated by two empty boxes, and the cue consisted of the onset and/or offset of an arrowhead located just under one of the two boxes. Different time intervals were used between cue and target. Subjects were instructed to ignore the cue and to respond to the target (a cross inside one of the two boxes). The data showed only consistent effects of inhibition (inhibition of return) with the long intervals, but the pattern was different depending on the cue type. The amount of inhibition was much greater when the onset of the cue was followed by its offset. Apparently, inhibition of return depended on the dynamic changes of the cue. Received: 23 October 1996 / Accepted: 3 June 1997     

Color search and visual field segregation

Visual search for targets that combine color and shape features that are shared by distracting items can be conducted spatially in parallel. Experimental results show that parallel search for color/shape conjunctions is possible when the shapes chosen let observers segregate the spatially interspersed items into figure and ground and when, within the figure, the target differs from other items by a distinguishing color feature. Results of experiments that manipulate stimulus color suggest that adaptive mechanisms of color discrimination are used to detect targets within such a figure.     

Attention shifts produce spatial stimulus codes

Summary In the Simon task the spatial position of the stimulus, though task irrelevant, influences speed of response. We (Umiltà & Nicoletti, 1992) proposed that the orienting of attention to the imperative stimulus produces a Stroop-like interference. This paper reports the results of three experiments that provide empirical support for two predictions of this hypothesis. One is that the stimulus spatial code is formed with relation to the position to which attention is directed. The other prediction is that the Simon effect is obtained on condition that attention can orient to the stimulus.Some of the results of Experiments 1 and 2 were reported briefly in Umiltà and Nicoletti (1992)     

The interplay of community and family risk and protective factors on adjustment in young adult immigrants

We examined the direct and interactive effects of community violence and both family cohesion and conflict on collective efficacy and aggressive behaviours among immigrant young adults. Participants included 221 young adults (ages 18–26; mean age = 21.36; 45.7% female, 190 born outside the U.S.) who completed self-report measures of their exposure to neighbourhood violence, social cohesion, collective efficacy and prosocial behaviours toward friends and strangers. Results, in general, showed that community violence and family cohesion were positively associated with collective efficacy whereas community violence and family conflict were positively associated with aggressive behaviours. Family cohesion and conflict also moderated the links between community violence and aggressive behaviours. Discussion focuses on the interplay of community and family processes and the relations to adjustment of immigrant young adults.     

Global/local processing and negative priming: the influence of selection difficulty and stimulus exposure

Negative priming is a decrement in performance observed when a previously ignored stimulus is re-presented as a target. The present study examined the relation between selection difficulty and negative priming in five experiments that used hierarchical stimuli (large letters made up by small letters). The results show that negative priming is greater when subjects direct attention to the local level (more difficult selection) than when they direct attention to the global level (less difficult selection). However, that occurs only when exposure of prime and probe is sufficiently long. With shorter presentations, negative priming is still observed but is no longer modulated by selection difficulty. These results suggest that both anticipatory and reactive mechanisms are responsible for the occurrence of negative priming and that instantiation of the reactive mechanism depends on the time available for prime and probe selection. Received: 17 January 2000 / Accepted: 3 July 2000