Selective impairment in visual perception of biological motion in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is associated with a variety of well-documented cognitive deficits such as deficits in memory and executive functioning, but little is known about basic perceptual concomitants of OCD. This study investigated global, configural processing in OCD using dynamic (moving) and static stimuli with minimal demands on cognitive function. Twenty OCD patients and 16 age- and education-matched healthy control subjects were tested on four perceptual tasks: two motion tasks involved detection and discrimination of human activity portrayed by point-light animations ("biological" motion). The other two tasks involved detection of coherent, translational motion defined by random-dot cinematograms and detection of static global shape defined by spatially distributed contours. OCD patients exhibited impaired performance on biological motion tasks; in contrast, their performance on tasks of coherent motion detection and global form perception were comparable to those of healthy controls. These results indicate that OCD patients have a specific deficit in perceiving biological motion signals, whereas their perception of non-biological coherent motion and static global shape is intact. Because efficient social interactions depend on accurate and rapid perception of subtle socially relevant cues, deficits in biological motion perception may compromise social functioning in people with OCD.     

Interaction of visual hemifield and body view in biological motion perception

The brain network for the recognition of biological motion includes visual areas and structures of the mirror-neuron system. The latter respond during action execution as well as during action recognition. As motor and somatosensory areas predominantly represent the contralateral side of the body and visual areas predominantly process stimuli from the contralateral hemifield, we were interested in interactions between visual hemifield and action recognition. In the present study, human participants detected the facing direction of profile views of biological motion stimuli presented in the visual periphery. They recognized a right-facing body view of human motion better in the right visual hemifield than in the left; and a left-facing body view better in the left visual hemifield than in the right. In a subsequent fMRI experiment, performed with a similar task, two cortical areas in the left and right hemispheres were significantly correlated with the behavioural facing effect: primary somatosensory cortex (BA 2) and inferior frontal gyrus (BA 44). These areas were activated specifically when point-light stimuli presented in the contralateral visual hemifield displayed the side view of their contralateral body side. Our results indicate that the hemispheric specialization of one's own body map extends to the visual representation of the bodies of others.     

Cerebral laterality, perception of emotion, and treatment response in obsessive-compulsive disorder

Patients with obsessive-compulsive disorder (OCD) had lower right-ear advantages than healthy controls on five different language-related dichotic listening tests of cerebral laterality. This abnormality was more pronounced in patients with more severe illness. Stimulus pairs in one test consisted of one word with a positive emotional valence and one emotionally neutral word. Pairs in another test consisted of one negative and one neutral word. Patients with OCD tended to hear fewer emotion-related words than did healthy controls, a finding also noted in depressed patients. Moreover, OCD patients who responded to treatment with serotonin reuptake inhibitors heard fewer emotion-related words than did nonresponders.     

Inflated perception of responsibility for harm in obsessive-compulsive disorder

The present study examined the proposition that inflated responsibility is implicated in obsessive compulsive disorder (OCD). Compared to non-anxious control participants (NACs), and an anxious control group with generalized social phobia (GSPs), we predicted that individuals with OCD (OCs) would exhibit a greater urge to rectify situations involving potential risk, would report more distress upon leaving such situations unrectified, and would feel more personal responsibility if the unrectified situations resulted in harm. Fifteen OCs, 15 NACs, and 15 GSPs completed the Obsessive Compulsive Responsibility Scale (OCRS), which included low-risk, OC-relevant, and high-risk situations. Compared to NACs and GSPs, OCs reported more urges, distress, and responsibility in low-risk and OC-relevant situations; no group differences were detected on high-risk situations. GSPs and NACs differed only in their responsibility in OC-relevant situations, with GSPs reporting higher responsibility than controls. Our results suggest that compared to OCs, NACs, and GSPs can better differentiate between situations that merit concern and ones that do not.     

Enhanced visual latent inhibition in obsessive-compulsive disorder.

BACKGROUND: Latent inhibition (LI) is the slowed acquisition of a learned response to a conditioned stimulus (CS), that occurs if that CS has previously been experienced in a noncontingent setting. This retarded acquisition is thought to occur because, due to the previous noncontingent experience, an individual must "unlearn the irrelevance" of the CS, before learning its new association to the unconditioned stimulus. A previous report using an auditory paradigm did not detect abnormal LI in obsessive-compulsive disorder (OCD) subjects; this auditory LI task included a difficult acquisition phase, which made it relatively insensitive to detecting abnormally elevated LI (i.e., slowed "unlearning"). METHODS: We assessed LI using a highly sensitive computerized visual LI paradigm in 63 carefully screened control subjects and in 48 patients with OCD. RESULTS: Compared to controls, OCD subjects exhibited significantly more LI; if "preexposed" to a to-be-CS, OCD subjects required significantly more trials to learn a new association to that CS, compared to control subjects. This pattern was particularly evident in unmedicated OCD subjects. CONCLUSIONS: The inflated impact of preexposure on LI response acquisition in OCD subjects may be a quantitative measure of their tendency to remain "stuck in set" in this cognitive task.     

Absence of placebo response in obsessive-compulsive disorder

Analyses in 30 patients with a diagnosis of obsessive-compulsive disorder given single-blind placebo over a 2-week period and of 12 of these patients who continued treatment on double-blind placebo for an additional 10 weeks revealed virtual absence of improvement on both clinician and self-rating scales of obsessions, compulsions, phobias, depression, and anxiety. This result would imply that the contribution of the placebo effect to the pharmacotherapy of patients with obsessive-compulsive disorder is negligible although considerable effort and work is still required to reliably identify one of four panic disorder with agoraphobia patients who respond to placebo. The placebo response thus presents a clear distinction between these two phenomenologically complex anxiety disorders.     

Auditory motion affects visual biological motion processing

The processing of biological motion is a critical, everyday task performed with remarkable efficiency by human sensory systems. Interest in this ability has focused to a large extent on biological motion processing in the visual modality (see, for example, Cutting, J. E., Moore, C., & Morrison, R. (1988). Masking the motions of human gait. Perception and Psychophysics, 44(4), 339-347). In naturalistic settings, however, it is often the case that biological motion is defined by input to more than one sensory modality. For this reason, here in a series of experiments we investigate behavioural correlates of multisensory, in particular audiovisual, integration in the processing of biological motion cues. More specifically, using a new psychophysical paradigm we investigate the effect of suprathreshold auditory motion on perceptions of visually defined biological motion. Unlike data from previous studies investigating audiovisual integration in linear motion processing [Meyer, G. F. & Wuerger, S. M. (2001). Cross-modal integration of auditory and visual motion signals. Neuroreport, 12(11), 2557-2560; Wuerger, S. M., Hofbauer, M., & Meyer, G. F. (2003). The integration of auditory and motion signals at threshold. Perception and Psychophysics, 65(8), 1188-1196; Alais, D. & Burr, D. (2004). No direction-specific bimodal facilitation for audiovisual motion detection. Cognitive Brain Research, 19, 185-194], we report the existence of direction-selective effects: relative to control (stationary) auditory conditions, auditory motion in the same direction as the visually defined biological motion target increased its detectability, whereas auditory motion in the opposite direction had the inverse effect. Our data suggest these effects do not arise through general shifts in visuo-spatial attention, but instead are a consequence of motion-sensitive, direction-tuned integration mechanisms that are, if not unique to biological visual motion, at least not common to all types of visual motion. Based on these data and evidence from neurophysiological and neuroimaging studies we discuss the neural mechanisms likely to underlie this effect.     

Activation in the MT-complex during visual perception of apparent motion and temporal succession

Previous studies have shown that MT (i.e., the MT-complex) is activated during visual perception of apparent motion. To further explore the function of MT, we measured activation in MT by positron emission tomography (PET) using a broad range of stroboscopic stimulus events in which (a) the frame rate was so fast that observers perceived stimulus frames as simultaneous, (b) the frame rate was slower and generated compelling impressions of apparent motion, or (c) the frame rate was so slow that observers perceived temporal succession (successive views of the same objects at different locations) instead of motion. As expected, the simultaneity condition showed no activation (reliable increase in regional cerebral blood flow, rCBF) in MT whereas the motion condition showed activation in both left and right MT. However, the succession condition showed even stronger activation in left and right MT than did the motion condition. MT seems implicated in perception of retinal stimuli as successive views of the same object at different locations whether or not the views are connected by apparent motion.     

Evidence for a biological hypothesis of obsessive-compulsive disorder

There is scant but provocative evidence to support the concept of a biological etiology in obsessive-compulsive disorder (OCD). This evidence includes the phenomenologic similarities and associations with other major psychiatric disorders for which there is evidence of biologic etiologies; the genetic studies that show an increased familial occurrence of psychiatric illness including OCD and concordance for this disorder in monozygotic twins; biologic evidence and the historical association of OCD and CNS damage; the treatment response of OCD to antidepressant medication and possibly those medications that selectively modify serotonin neuronal activity and to selective anterior limbic leukotomy. This evidence and the evidence linking OCD to depressive illness are specifically reviewed and discussed.     

Predictors of treatment response in pediatric obsessive-compulsive disorder

ObjectiveTo examine predictors of treatment response in pediatric obsessive-compulsive disorder (OCD).MethodA literature review of psychotherapy (i.e., cognitive-behavioral therapy) and medication studies for pediatric OCD published from 1985 to 2007 was conducted using several databases.ResultsThe literature search produced a total of 21 studies (6 cognitive-behavioral therapy, 13 medication, and 2 combination studies) that met specific methodological criteria. Across studies, the following nine predictors were examined: child sex, child age, duration of illness/age at onset, baseline severity of obsessive-compulsive symptoms, type of obsessive-compulsive symptoms, comorbid disorders/symptoms, psychophysiological factors, neuropsychological factors, and family factors. Among all of the studies, there was little evidence that sex, age, or duration of illness (age at onset) was associated with treatment response. Baseline severity of obsessive-compulsive symptoms and family dysfunction were associated with poorer response to cognitive-behavioral therapy, whereas comorbid tics and extermalizing disorders were associated with poorer response in medication-only studies.ConclusionsOverall, there are limited data on predictors of treatment response for pediatric OCD. The majority of studies are plagued with methodological limitations and post hoc approaches. Additional research is needed to better delineate the predictors of treatment response in pediatric OCD with the goal of developing individualized treatment approaches. J. Am. Acad. Child Adolesc. Psychiatry, 2008;47(8):868-878.     

Effects of cognitive self-consciousness on visual memory in obsessive-compulsive disorder

Previous research has documented high trait cognitive self-consciousness (CSC) in obsessive-compulsive disorder (OCD). It remains unclear whether elevated CSC levels can also explain cognitive performance deficits that have frequently been found in OCD. This study examined whether experimentally heightened CSC affects visual memory performance in OCD. OCD participants and healthy controls completed a complex figure test under three experimental conditions: simultaneously focusing on their thoughts (= CSC condition), simultaneously focusing on acoustic stimuli (= dual-task condition), and without a parallel task (= standard condition). In the OCD sample both the CSC condition and the dual-task condition reduced memory performance compared to the standard condition, whereas in controls only the dual-task condition led to reduced performance. Results indicate that raising CSC in OCD has a deteriorating effect on memory encoding that parallels the effect of a secondary task. High CSC and its effects on cognitive performance might be amenable to meta-cognitive treatment approaches.     

Brain areas involved in perception of biological motion

These experiments use functional magnetic resonance imaging (fMRI) to reveal neural activity uniquely associated with perception of biological motion. We isolated brain areas activated during the viewing of point-light figures, then compared those areas to regions known to be involved in coherent-motion perception and kinetic-boundary perception. Coherent motion activated a region matching previous reports of human MT/MST complex located on the temporo-parieto-occipital junction. Kinetic boundaries activated a region posterior and adjacent to human MT previously identified as the kinetic-occipital (KO) region or the lateral-occipital (LO) complex. The pattern of activation during viewing of biological motion was located within a small region on the ventral bank of the occipital extent of the superior-temporal sulcus (STS). This region is located lateral and anterior to human MT/MST, and anterior to KO. Among our observers, we localized this region more frequently in the right hemisphere than in the left. This was true regardless of whether the point-light figures were presented in the right or left hemifield. A small region in the medial cerebellum was also active when observers viewed biological-motion sequences. Consistent with earlier neuroimaging and single-unit studies, this pattern of results points to the existence of neural mechanisms specialized for analysis of the kinematics defining biological motion.     

Frontal-striatal dysfunction during planning in obsessive-compulsive disorder

BACKGROUND: Dysfunction of frontal-striatal, particularly orbitofrontal-striatal, circuitry has been implicated in the pathophysiology of obsessive-compulsive disorder (OCD), characterized by obsessions, ritualistic behavior, anxiety, and specific cognitive impairments. In addition, neuropsychological studies in OCD have reported impairments in visuospatial tasks and executive functions, such as planning. OBJECTIVE: To determine whether dorsal prefrontal-striatal dysfunction mediates planning impairment in patients with OCD. DESIGN: A parametric self-paced pseudorandomized event-related functional magnetic resonance imaging version of the Tower of London task was used in 22 medication-free patients with OCD and 22 healthy control subjects. This paradigm, allowing flexible responding and post hoc classification of correct responses, was developed to compare groups likely to differ in performance. RESULTS: Behavioral results showed significant planning impairments in OCD patients compared with control subjects. During planning, decreased frontal-striatal responsiveness was found in OCD patients, mainly in dorsolateral prefrontal cortex and caudate nucleus. In addition, OCD patients showed increased, presumably compensatory, involvement of brain areas known to play a role in performance monitoring and short-term memory processing, such as anterior cingulate, ventrolateral prefrontal, and parahippocampal cortices. CONCLUSIONS: These findings support the hypothesis that decreased dorsal prefrontal-striatal responsiveness is associated with impaired planning capacity in OCD patients. Because the described frontal-striatal dysfunction in OCD is independent of state anxiety and disease symptom severity, we conclude that executive impairment is a core feature in OCD.     

Abnormal visual event-related potentials in obsessive-compulsive disorder without panic disorder or depression comorbidity

Visual event-related potentials and spline map topography during a discriminative response task (DRT) were studied in 8 obsessive-compulsive disorder (OCD) patients without comorbidity for panic disorder or depression and in 12 age-matched controls. In the DRT task (like in a go/no-go task) the subject had to press a button when the target stimuli appeared and had to retain the response when the non-target stimulus appeared (vertical bars were intermixed with an equal probability of horizontals). OC patients had greater N1 latency than controls and their N1 and P3 amplitude was larger for the target stimuli, but not for non-target stimuli. In the normals, non-target stimuli (no-go task) produced a larger activation than target stimuli (go task). In the OCD patients the target stimuli produced the same large activation as the non-target. These findings are consistent with theories that consider OCD to be an attentional disorder deriving from a misallocating of cognitive resources. Moreover, spline map topography confirmed that P3 hyperactivation is localised principally on the frontal lobes.     

Altered perception of apparent motion in schizophrenia spectrum disorder

Apparent motion (AM), the Gestalt perception of motion in the absence of physical motion, was used to study perceptual organization and neurocognitive binding in schizophrenia. Associations between AM perception and psychopathology as well as meaningful subgroups were sought. Circular and stroboscopic AM stimuli were presented to 68 schizophrenia spectrum patients and healthy participants. Psychopathology was measured using the Positive and Negative Syndrome Scale (PANSS). Psychopathology was related to AM perception differentially: Positive and disorganization symptoms were linked to reduced gestalt stability; negative symptoms, excitement and depression had opposite regression weights. Dimensions of psychopathology thus have opposing effects on gestalt perception. It was generally found that AM perception was closely associated with psychopathology. No difference existed between patients and controls, but two latent classes were found. Class A members who had low levels of AM stability made up the majority of inpatients and control subjects; such participants were generally young and male, with short reaction times. Class B typically contained outpatients and some control subjects; participants in class B were older and showed longer reaction times. Hence AM perceptual dysfunctions are not specific for schizophrenia, yet AM may be a promising stage marker.     

Processing of local and global visual features in obsessive-compulsive disorder.

Research conducted with the Rey-figure task has suggested that patients with obsessive-compulsive disorder (OCD) process local aspects of a complex stimulus more efficiently than the overall gestalt. The aim of the present study was to investigate if this "local bias" is established already during early stimulus encoding or occurs only during later processing, once a percept has been formed (e.g., memory retrieval). To this end, responding to local and global targets of hierarchical letters (e.g., an "E" composed out of small "T"s) was assessed in 30 OCD patients and 28 healthy controls. OCD patients and controls performed comparably on all parameters. These results lend no support to the notion of an early perceptual bias towards local elements in OCD patients. It remains to be tested whether a bias towards local features is confined to situations where local and global features compete for selection.     

Impaired visual recognition of biological motion in schizophrenia

BACKGROUND: Motion perception deficits have been suggested to be an important feature of schizophrenia but the behavioral consequences of such deficits are unknown. Biological motion refers to the movements generated by living beings. The human visual system rapidly and effortlessly detects and extracts socially relevant information from biological motion. A deficit in biological motion perception may have significant consequences for detecting and interpreting social information. METHODS: Schizophrenia patients and matched healthy controls were tested on two visual tasks: recognition of human activity portrayed in point-light animations (biological motion task) and a perceptual control task involving detection of a grouped figure against the background noise (global-form task). Both tasks required detection of a global form against background noise but only the biological motion task required the extraction of motion-related information. RESULTS: Schizophrenia patients performed as well as the controls in the global-form task, but were significantly impaired on the biological motion task. In addition, deficits in biological motion perception correlated with impaired social functioning as measured by the Zigler social competence scale [Zigler, E., Levine, J. (1981). Premorbid competence in schizophrenia: what is being measured? Journal of Consulting and Clinical Psychology, 49, 96-105.]. CONCLUSION: The deficit in biological motion processing, which may be related to the previously documented deficit in global motion processing, could contribute to abnormal social functioning in schizophrenia.     

Growth hormone response to apomorphine in obsessive-compulsive disorder.

Several lines of evidence suggest that dopamine plays a role in the pathophysiology of obsessive-compulsive disorder (OCD). Indeed, some trials have shown the efficacy of neuroleptic addition in the treatment of OCD patients. In this study, we assessed the growth hormone (GH) response to 0.5 mg apomorphine(sc) in 8 drug-free inpatients (6 male, 2 female; mean age +/- SD = 34.7 +/- 12.6) meeting DSM-III-R criteria for OCD without major depression and compared their responses with those of 8 healthy male volunteers (mean age = 27.1 +/- 8.5). The groups did not differ in their mean GH peak response: 12.4 +/- 9.7 ng/mL in OCD patients versus 21.1 +/- 14.2 ng/mL in normal controls (F = 0.9, df1, 14, P = 0.37). These results do not support the hypothesis of dopaminergic overactivity in OCD. In fact, the completely blunted GH response to apomorphine in 2 OCD patients suggests the biological heterogeneity of OCD. Some dopaminergic disturbances could be observed in patients with comorbid diagnoses or patients unresponsive to serotonin reuptake inhibitors, but the results of this study require confirmation from a larger sample with a precise assessment of comorbidity.