Brain activation during implicit sequence learning in individuals with trichotillomania

Trichotillomania (TTM) may be related to obsessive-compulsive disorder (OCD) and other neuropsychiatric conditions characterized by cortico-striatal dysfunction. Functional imaging studies of OCD using an implicit learning task have found abnormalities in striatal and hippocampal activation. The current study investigated whether similar abnormalities occur in TTM. Functional MRI and the serial reaction time (SRT) task were used to assess striatal and hippocampal activation during implicit sequence learning in TTM and healthy control (HC) subjects. The results for 20 age- and education-matched participants (10 TTM, 10 HC) are reported. In comparison with HC participants, those with TTM exhibited no significant differences in implicit learning, or in activation within the striatum, hippocampus, or other brain regions. The current findings do not provide evidence for cortico-striatal dysfunction in TTM. Future studies directly comparing OCD and TTM subjects are warranted to confirm the specificity of abnormal striatal and hippocampal findings during implicit sequence learning in OCD.     

Functional magnetic resonance imaging evidence for a lack of striatal dysfunction during implicit sequence learning in individuals with animal phobia

OBJECTIVE: This study investigated the neural substrates of implicit sequence learning in subjects with and without small animal phobia, in a follow-up to analogous studies of obsessive-compulsive disorder (OCD). METHOD: Ten subjects with specific phobia and 10 healthy comparison subjects were studied by using a serial reaction time task paradigm and functional magnetic resonance imaging. RESULTS: A main effect of condition (implicit sequence learning versus random sequence) was observed across diagnostic groups in the right striatum, as well as in other regions. In the striatum, the a priori region of interest, there were no significant effects of diagnosis or the interaction of diagnosis and condition. CONCLUSIONS: Brain activation in the striatum of subjects with specific phobia does not significantly differ from that of normal comparison subjects during implicit sequence learning. This suggests different pathophysiological mechanisms for specific phobia in contrast to OCD, in which deficient striatal recruitment has been reproducibly found with this paradigm. This approach offers promise for demonstrating diagnostic specificity across different neuropsychiatric disorders based on the presence or absence of deficient striatal activation.     

Striatal recruitment during an implicit sequence learning task as measured by functional magnetic resonance imaging

Prior research has repeatedly implicated the striatum in implicit sequence learning; however, imaging findings have been inconclusive with respect to the sub-territories and laterality involved. Using functional magnetic resonance imaging (fMRI), we studied brain activation profiles associated with performance of the serial reaction time task (SRT) in 10 normal right-handed males. Behavioral results indicate that significant implicit learning occurred, uncontaminated by significant explicit knowledge. Concatenated fMRI data from the entire cohort revealed significant right-lateralized activation in both the caudate and putamen. Analysis of fMRI data from individual subjects showed inter-individual variability as to the precise territories involved, including right as well as left caudate and putamen. Interestingly, all seven subjects who manifested robust learning effects exhibited significant activation within the putamen. Moreover, among those seven subjects, the magnitude of signal intensity change within the putamen correlated significantly with the magnitude of reaction time advantage achieved. These findings demonstrate right-sided striatal activation across subjects during implicit sequence learning, but also highlight interindividual variability with respect to the laterality and striatal subterritories involved. In particular, results from individual subjects suggest that, during the SRT, the reaction time advantage garnered via implicit sequence learning might be predominantly associated with activity within the putamen.     

A study of parallel implicit and explicit information processing in patients with obsessive-compulsive disorder

OBJECTIVE: This study examined implicit sequence learning in patients with obsessive-compulsive disorder (OCD) under dual-task conditions. Frontal-striatal networks support implicit learning and are implicated in the pathophysiology of OCD. Neuroimaging data suggest that during implicit learning, OCD patients use neural systems normally active during explicit learning to compensate for striatal dysfunction. METHOD: The authors examined implicit sequence learning in 25 OCD patients and 25 healthy comparison subjects using a dual-task paradigm, with subjects simultaneously engaged in an explicit memory task and an implicit learning task. They predicted that implicit learning in OCD subjects would be disrupted because concurrent explicit information-processing demands would prevent use of compensatory processes. RESULTS: OCD patients failed to show evidence of implicit learning and exhibited a significant deficit in comparison with healthy subjects. CONCLUSIONS: These results are consistent with the hypothesis that concurrent explicit and implicit information-processing demands interfere with implicit learning in OCD patients.     

Deficit in schizophrenia to recruit the striatum in implicit learning: a functional magnetic resonance imaging investigation

In schizophrenia, explicit learning deficits have been well established although it is less clear whether these patients have deficits in implicit learning (IL). IL is thought to depend on intact striatal functioning. This study examined the hypothesis that schizophrenia patients show deficient recruitment of striatal activation during an IL paradigm, relative to performance-matched healthy comparison subjects. Ten subjects with schizophrenia on atypical antipsychotic medication and 10 age, gender, education, and performance matched healthy comparison subjects underwent fMRI while performing an IL task. On the basis of whole-brain and striatal region-of-interest analyses, we found a relative lack of striatal activation in schizophrenia patients. This result is consistent with convergent evidence of striatal dysfunction in schizophrenia.     

Prefrontal and striatal activation during sequence learning in geriatric depression.

BACKGROUND: Frontostriatal dysfunction is a primary hypothesis for the neurocognitive changes of depression in late life. The aim of the present study was to test this hypothesis with the use of functional magnetic resonance imaging (fMRI) tasks that are known to engage the prefrontal and neostriatal cognitive circuits. METHODS: Twenty-three elderly subjects (mean age, 69.9 years) participated: 11 subjects with a current major depressive episode and 12 nondepressed elderly control subjects. Subjects underwent fMRI while performing a concurrent implicit and explicit sequence learning task. Region of interest (ROI)-based analyses were conducted, focusing on the dorsal anterior cingulate cortex, the dorsolateral prefrontal cortex, and the neostriatum. RESULTS: As expected, both the control and depressed subjects learned the sequence during both implicit and explicit conditions. During explicit learning, decreased prefrontal activation was found in the depressed subjects, along with increased striatal activation. The increased striatal activity in the depressed subjects was due to increased activity on the trials that violated the sequence. During implicit learning, no significant differences were found between the groups in the identified ROIs. CONCLUSIONS: The increased striatal activation on trials that violated the sequence demonstrates a greater response to negative feedback for depressed compared with control subjects. Our observations of significant differences in both prefrontal and striatal regions in the depressed elderly subjects relative to elderly control subjects supports the frontostriatal dysfunction hypothesis of late-life depression.     

Distinct neural correlates of washing, checking, and hoarding symptom dimensions in obsessive-compulsive disorder

CONTEXT: Obsessive-compulsive disorder (OCD) is clinically heterogeneous, yet most previous functional neuroimaging studies grouped together patients with mixed symptoms, thus potentially reducing the power and obscuring the findings of such studies. OBJECTIVE: To investigate the neural correlates of washing, checking, and hoarding symptom dimensions in OCD. DESIGN: Symptom provocation paradigm, functional magnetic resonance imaging, block design, and nonparametric brain mapping analyses. SETTING: University hospital. PARTICIPANTS: Sixteen patients with OCD (11 inpatients, 5 outpatients) with mixed symptoms and 17 healthy volunteers of both sexes.Intervention All subjects participated in 4 functional magnetic resonance imaging experiments. They were scanned while viewing alternating blocks of emotional (washing-related, checking-related, hoarding-related, or aversive, symptom-unrelated) and neutral pictures, and imagining scenarios related to the content of each picture type.Main Outcome Measure Blood oxygenation level-dependent response. RESULTS: Both patients and control subjects experienced increased subjective anxiety during symptom provocation (patients significantly more so) and activated neural regions previously linked to OCD. Analyses of covariance, controlling for depression, showed a distinct pattern of activation associated with each symptom dimension. Patients demonstrated significantly greater activation than controls in bilateral ventromedial prefrontal regions and right caudate nucleus (washing); putamen/globus pallidus, thalamus, and dorsal cortical areas (checking); left precentral gyrus and right orbitofrontal cortex (hoarding); and left occipitotemporal regions (aversive, symptom-unrelated). These results were further supported by correlation analyses within patients, which showed highly specific positive associations between subjective anxiety, questionnaire scores, and neural response in each experiment. There were no consistently significant differences between patients with (n = 9) and without (n = 7) comorbid diagnoses. CONCLUSIONS: The findings suggest that different obsessive-compulsive symptom dimensions are mediated by relatively distinct components of frontostriatothalamic circuits implicated in cognitive and emotion processing. Obsessive-compulsive disorder may be best conceptualized as a spectrum of multiple, potentially overlapping syndromes rather than a unitary nosologic entity.     

Impaired procedural learning in obsessive-compulsive disorder and Parkinson's disease, but not in major depressive disorder

The striatum has been consistently implicated in the pathophysiology of obsessive-compulsive disorder (OCD), yet, studies assessing the performance of OCD patients in procedural learning tasks, assumed to rely on the intact functioning of the striatum, have yielded inconsistent results. Recently, Rauch et al. [Rauch SL, Savage CR, Alpert NM, Dougherty D, Kendrick A, Curran T, et al. Probing striatal function in obsessive-compulsive disorder: a PET study of implicit sequence learning. J Neuropsychiatry Clin Neurosci 1997;9:568-73] have obtained evidence suggesting that seemingly intact performance of OCD patients in such tasks may be achieved by recruiting systems which in normal subjects are reserved for explicit or declarative, rather than implicit or procedural, processing. The present study assessed procedural learning in OCD patients using a card betting task in which explicit processing impairs, rather than assists, acquisition. In addition, we tested a group of Parkinson's disease (PD) patients, in order to better establish the dependence of the task on procedural learning, and a group of major depressive disorder (MDD) patients, in order to test the possibility that impaired learning in the card betting task may be a result of concurrent depression. The majority of OCD (15/18) and PD patients (14/16) did not acquire the task, whereas MDD patients acquired the task similarly to normal control subjects. These results demonstrate that OCD patients are impaired on a procedural learning task in which explicit processing impairs acquisition. Two different interpretations are suggested: that the striatal system is dysfunctional in OCD, or that inappropriate explicit processing in OCD interferes with the functioning of the striatal system.     

The role of the striatum in implicit learning: a functional magnetic resonance imaging study

Previous research has posited striatal involvement in implicit learning. However, imaging studies have not directly compared learners with non-learners. Using functional magnetic resonance imaging with 15 study participants, we used an implicit learning task previously associated with striatal recruitment. Dorsal and ventral striatum activation was observed in the eight participants who demonstrated implicit learning. Ventral striatum activations occurred to a greater extent in implicit learning versus non-implicit learning participants, and were correlated with the degree of reaction time advantage in implicit learning participants, even after controlling for general decreases in reaction time over time. These findings strengthen the specificity of the striatum in implicit learning and are suggestive of a dissociation of striatal regions relative to elements of implicit learning performance.     

Error-related hyperactivity of the anterior cingulate cortex in obsessive-compulsive disorder.

BACKGROUND: Hyperactivity of the anterior cingulate cortex (ACC) in patients with obsessive-compulsive disorder (OCD) has been shown to increase with symptom provocation and to normalize with treatment-induced symptom reduction. Although the functional significance of anterior cingulate involvement in OCD remains unknown, electrophysiological evidence has linked this region to error-processing abnormalities in patients with OCD. In this functional magnetic resonance imaging (fMRI) study, we sought to further localize error-processing differences within the ACC of OCD patients compared with healthy subjects. METHODS: Event-related fMRI data were collected for eight OCD patients and seven healthy subjects during the performance of a simple cognitive task designed to elicit errors but not OCD symptoms. RESULTS: Both OCD patients and healthy subjects demonstrated dorsal ACC activation during error commission. The OCD patients exhibited significantly greater error-related activation of the rostral ACC than comparison subjects. Activity in this region was positively correlated with symptom severity in the patients. CONCLUSIONS: Error-processing abnormalities within the rostral anterior cingulate occur in the absence of symptom expression in patients with OCD.     

Aberrant ventral striatal responses during incentive processing in unmedicated patients with obsessive-compulsive disorder

Jung WH, Kang D‐H, Han JY, Jang JH, Gu B‐M, Choi J‐S, Jung MH, Choi C‐H, Kwon JS. Aberrant ventral striatal responses during incentive processing in unmedicated patients with obsessive–compulsive disorder. Objective: Obsessive–compulsive disorder (OCD) is characterized by the dysfunction of control and reward mechanisms. However, only few neuroimaging studies of OCD have examined the reward processing. We examined the neural responses during incentive processing in OCD. Method: Twenty unmedicated patients with OCD and 20 age‐, sex‐, and IQ‐matched healthy controls underwent functional magnetic resonance imaging while performing a modified monetary incentive delay task. Results: Compared with controls, patients with OCD showed increased ventral striatal activation in the no‐loss minus loss outcome contrast and a significant positive correlation between the ventral striatal activation and compulsion symptom severity. In addition, patients with OCD showed increased activations in the frontostriatal regions in the gain minus no‐gain outcomes contrast. During loss anticipation, patients with OCD showed less activations in the lateral prefrontal and inferior parietal cortices. However, during gain anticipation, patients with OCD and healthy controls did not differ in the ventral striatal activation. Conclusion: These findings provide neural evidence for altered incentive processing in unmedicated patients with OCD, suggesting an elevated sensitivity to negatively affect stimuli as well as dysfunction of the ventral striatum.     

Striatal function in generalized social phobia: a functional magnetic resonance imaging study.

BACKGROUND: Although evidence suggests the involvement of the amygdala in generalized social phobia (GSP), few studies have examined other neural regions. Clinical, preclinical, and dopamine receptor imaging studies demonstrating altered dopaminergic functioning in GSP suggest an association with striatal dysfunction. This is the first functional magnetic resonance imaging (fMRI) study to use a cognitive task known to involve the striatum to examine the neural correlates of GSP. We examined whether subjects with GSP had differential activation in striatal regions compared with healthy control subjects while engaged in a cognitive task that has been shown to activate striatal regions reliably. METHODS: Ten adult, unmedicated subjects with a primary DSM-IV diagnosis of GSP and 10 age-, gender-, and education-matched healthy comparison subjects underwent fMRI while performing the implicit sequence learning task. RESULTS: The GSP and healthy comparison subjects did not differ significantly on the behavioral performance of the task. Subjects with GSP, however, had significantly reduced neural activation related to implicit learning compared with healthy comparison subjects in the left caudate head, left inferior parietal lobe, and bilateral insula. CONCLUSIONS: These findings support the hypothesis that GSP is associated with striatal dysfunction and further the neurobiological understanding of this complex anxiety disorder.     

Neurobiological model of obsessive–compulsive disorder: Evidence from recent neuropsychological and neuroimaging findings

Obsessive–compulsive disorder (OCD) was previously considered refractory to most types of therapeutic intervention. There is now, however, ample evidence that selective serotonin reuptake inhibitors and behavior therapy are highly effective methods for treatment of OCD. Furthermore, recent neurobiological studies of OCD have found a close correlation between clinical symptoms, cognitive function, and brain function. A large number of previous neuroimaging studies using positron emission tomography, single‐photon emission computed tomography or functional magnetic resonance imaging (fMRI) have identified abnormally high activities throughout the frontal cortex and subcortical structures in patients with OCD. Most studies reported excessive activation of these areas during symptom provocation. Furthermore, these hyperactivities were decreased after successful treatment using either selective serotonin reuptake inhibitors or behavioral therapy. Based on these findings, an orbitofronto‐striatal model has been postulated as an abnormal neural circuit that mediates symptomatic expression of OCD. On the other hand, previous neuropsychological studies of OCD have reported cognitive dysfunction in executive function, attention, nonverbal memory, and visuospatial skills. Moreover, recent fMRI studies have revealed a correlation between neuropsychological dysfunction and clinical symptoms in OCD by using neuropsychological tasks during fMRI. The evidence from fMRI studies suggests that broader regions, including dorsolateral prefrontal and posterior regions, might be involved in the pathophysiology of OCD. Further, we should consider that OCD is heterogeneous and might have several different neural systems related to clinical factors, such as symptom dimensions. This review outlines recent neuropsychological and neuroimaging studies of OCD. We will also describe several neurobiological models that have been developed recently. Advanced findings in these fields will update the conventional biological model of OCD.     

Neural Correlates of Symptom Dimensions in Pediatric Obsessive-Compulsive Disorder: A Functional Magnetic Resonance Imaging Study

ObjectiveNeuroimaging studies have identified distinct neural correlates of obsessive-compulsive disorder (OCD) symptom dimensions in adult subjects and may be related to functional abnormalities in different cortico-striatal-thalamic neural systems underlying cognition and affective processing. Similar symptom dimensions are apparent in childhood and adolescence, but their functional neural correlates remain to be elucidated.MethodPediatric subjects with OCD (n = 18) and matched controls (n = 18), ages 10 to 17 years, were recruited for two functional magnetic resonance imaging experiments. They were scanned while viewing alternating blocks of symptom provocation (contamination-related or symmetry-related) and neutral pictures and imagining scenarios related to the content of each picture type.ResultsThe subjects with OCD demonstrated reduced activity in the right insula, putamen, thalamus, dorsolateral prefrontal cortex, and left orbitofrontal cortex (contamination experiment) and in the right thalamus and right insula (symmetry experiment). Higher scores on OCD symptom-related measures (contamination and total severity) were significantly predictive of reduced neural activity in the right dorsolateral prefrontal cortex during the contamination experiment.ConclusionsOur findings indicate reduced activity in neural regions underlying emotional processing, cognitive processing, and motor performance in pediatric subjects with OCD compared with the controls. These between-group differences are present during both contamination and symmetry provocation experiments and during symptom provocation as well as viewing neutral pictures. The direction of activity is in contrast to adult findings in the insula and in components of cortico-striatal thalamic neural systems. Our findings suggest developmental effects on neural systems underlying symptom dimensions in pediatric OCD.     

Relationship between symptom dimensions and brain morphology in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is known as a clinically heterogeneous disorder characterized by symptom dimensions. Although substantial numbers of neuroimaging studies have demonstrated the presence of brain abnormalities in OCD, their results are controversial. The clinical heterogeneity of OCD could be one of the reasons for this. It has been hypothesized that certain brain regions contributed to the respective obsessive-compulsive dimensions. In this study, we investigated the relationship between symptom dimensions of OCD and brain morphology using voxel-based morphometry to discover the specific regions showing alterations in the respective dimensions of obsessive-compulsive symptoms. The severities of symptom dimensions in thirty-three patients with OCD were assessed using Obsessive-Compulsive Inventory-Revised (OCI-R). Along with numerous MRI studies pointing out brain abnormalities in autistic spectrum disorder (ASD) patients, a previous study reported a positive correlation between ASD traits and regional gray matter volume in the left dorsolateral prefrontal cortex and amygdala in OCD patients. We investigated the correlation between gray and white matter volumes at the whole brain level and each symptom dimension score, treating all remaining dimension scores, age, gender, and ASD traits as confounding covariates. Our results revealed a significant negative correlation between washing symptom dimension score and gray matter volume in the right thalamus and a significant negative correlation between hoarding symptom dimension score and white matter volume in the left angular gyrus. Although our result was preliminary, our findings indicated that there were specific brain regions in gray and white matter that contributed to symptom dimensions in OCD patients.     

A PET investigation of implicit and explicit sequence learning

The purpose of this study was to determine the mediating neuroanatomy of implicit and explicit sequence learning using a modified version of the serial reaction time (SRT) paradigm. Subjects were seven healthy, right-handed adults (three male, four female, mean age 26.7, range 18–43 yr). PET data were acquired via the oxygen-15-labeled-carbon dioxide inhalation method while subjects performed the SRT. Subjects were scanned during two blocks each of (1) no sequence (Random), (2) single-blind, 12-item sequence (Implicit), and (3) unblinded, same sequence (Explicit). Whole-brain-normalized images reflecting relative regional cerebral blood flow (rCBF) were transformed to Talairach space, and statistical parametric maps (SPMs) of z-scores were generated for comparisons of interest. The threshold for significant activation was defined as z-score ≥ 3.00. Behavioral data demonstrated significant learning (P < .05) for Implicit and Explicit conditions. Tests of explicit knowledge reflected non-significant explicit contamination during the Implicit condition. Foci of significant activation in the Implicit condition were found in right ventral premotor cortex, right ventral caudate/nucleus accumbens, right thalamus, and bilateral area 19; activation in the Explicit condition included primary visual cortex, peri-sylvian cortex, and cerebellar vermis. Activations in visual and language areas during the Explicit condition may reflect conscious learning strategies including covert verbal rehearsal and visual imagery. Right-sided premotor, striatal, and thalamic activations support the notion that implicit sequence learning is mediated by cortico-striatal pathways, preferentially within the right hemisphere. © 1996 Wiley-Liss, Inc.     

Neural correlates of anxiety associated with obsessive-compulsive symptom dimensions in normal volunteers.

BACKGROUND: The neural correlates of anxiety associated with obsessive-compulsive symptomlike provocation in normal volunteers are unknown. METHODS: Ten healthy volunteers participated in four functional magnetic resonance experiments. Subjects were scanned while viewing alternating blocks of emotional (normally aversive, washing-relevant, checking-relevant, or hoarding-relevant pictures) and neutral pictures, and imagining scenarios related to the content of each picture type. Nonparametric brain mapping analyses were used. RESULTS: In response to the provocative pictures in all experiments, increases in subjective anxiety and activation in bilateral ventral prefrontal, limbic, dorsal prefrontal, and visual regions were demonstrated. Anxiety related to different symptom dimensions was associated with different patterns of activation: provocation of washing-relevant anxiety predominantly activated dorsal and ventral prefrontal regions; checking-relevant anxiety predominantly activated dorsal prefrontal regions; and hoarding-relevant anxiety predominantly activated ventral prefrontal regions and the left amygdala. CONCLUSIONS: Our findings support a dimensional model of obsessive-compulsive disorder (OCD) whereby 1) the brain systems implicated in the mediation of anxiety in response to symptom-related material in normal subjects are similar to those identified in OCD patients during symptom provocation, and 2) anxiety associated with different symptom dimensions is associated with differential patterns of activation of these neural systems. Further investigation of the neural basis of OCD symptom dimensions is required.     

Ventral striatal activation during attribution of stimulus saliency and reward anticipation is correlated in unmedicated first episode schizophrenia patients

Patients with schizophrenia show deficits in motivation, reward anticipation and salience attribution. Several functional magnetic resonance imaging (fMRI) investigations revealed neurobiological correlates of these deficits, raising the hypothesis of a common basis in midbrain dopaminergic signaling. However, investigations of drug-na?ve first-episode patients with comprehensive fMRI tasks are still missing. We recruited unmedicated schizophrenia spectrum patients (N=27) and healthy control subjects (N=27) matched for sex, age and educational levels. An established monetary reward anticipation task in combination with a novel task aiming at implicit salience attribution without the confound of monetary incentive was applied. Patients showed reduced right ventral striatal activation during reward anticipation. Furthermore, patients with a more pronounced hypoactivation attributed more salience to neutral stimuli, had more positive symptoms and better executive functioning. In the patient group, a more differentially active striatum during reward anticipation was correlated positively to differential ventral striatal activation in the implicit salience attribution task. In conclusion, a deficit in ventral striatal activation during reward anticipation can already be seen in drug-na?ve, first episode schizophrenia patients. The data suggest that rather a deficit in differential ventral striatal activation than a generally reduced activation underlies motivational deficits in schizophrenia and that this deficit is related to the aberrant salience attribution.     

强迫症患者抑制功能受损的脑影像学特征

目的分析强迫症患者是否存在抑制功能受损,及其抑制功能受损的脑影像学特征。方法16例首次发病未用药的强迫症患者(强迫症组)和18名健康对照者(对照组)完成测查抑制功能的Go-Nogo任务,同步采集被试者任务态脑影像数据。采用方差分析比较强迫症组和对照组在Go条件和Nogo条件下平均反应时和反应正确率的组间差异,以及在成功反应抑制与错误监测过程中脑激活特征的组间差异。结果在Nogo条件下,强迫症组的正确率显著低于对照组(0.85±0.08比0.93±0.51;t=-3.06,P<0.05);在错误监测过程中,2组大脑激活模式存在差异,强迫症组双侧颞下回(左侧:t=3.11;右侧:t=2.71)、右侧额中回(t=2.52)、右侧海马旁回(t=2.53)、左侧后扣带回(t=3.03)大脑活动增强(均P<0.05);双侧壳核(左侧:t=-3.03;右侧:t=-3.12)、右侧额下回(t=-3.29)、右侧额上回(t=-3.12)、右侧中央前回(t=-2.91)大脑活动显著降低(均P<0.05)。结论强迫症患者存在抑制功能受损,在错误监测过程中相关脑区的功能活动存在异常。     

The involvement of distinct neural systems in patients with obsessive-compulsive disorder with autogenous and reactive obsessions

Besiroglu L, Sozen M, Ozbebit Ö, Avcu S, Selvi Y, Bora A, Atli A, Unal O, Bulut MD. The involvement of distinct neural systems in patients with obsessive–compulsive disorder (OCD) with autogenous and reactive obsessions. Objective: To investigate the regional metabolite abnormalities and changes after treatment in patients with OCD with autogenous and reactive obsessions. Method: We assessed right anterior cingulate cortex (ACC) and amygdala–hippocampal region (Am + Hpp) N‐acetyl‐aspartate (NAA), choline (Cho) and creatine (Cr) concentrations and NAA/Cr and Cho/Cr ratios using single‐voxel proton magnetic resonance spectroscopy in 15 patients with autogenous obsessions (OCD‐A), 15 patients with reactive obsessions (OCD‐R) and 15 healthy controls (HC). Measurements were repeated after 16 weeks of fluoxetine treatment. Results: Baseline ACC NAA/Cr ratios of both OCD groups were significantly lower than HC. OCD‐A group had significantly lower baseline NAA/Cr ratios in the Am + Hpp than other groups. These differences were more likely to be explained by higher Cr levels in ACC. We found no significant differences and changes for Cho levels and Cho/Cr ratios between groups and within groups. Significant increase in NAA/Cr ratios of OCD‐A group found in the Am + Hpp was more likely to be explained by increased NAA levels. No significant changes were found in ACC NAA/Cr ratios. Conclusion: While disturbed energy metabolism in ACC might reflect a common pathology in patients with OCD regardless of symptom dimension, alterations in mesiotemporal lobe are more likely for autogenous obsessions.