RESUMO
Obsessive-compulsive disorder (OCD) is a common psychiatric condition classically characterized by obsessions (recurrent, intrusive and unwanted thoughts) and compulsions (excessive, repetitive and ritualistic behaviors or mental acts). OCD is heterogeneous in its clinical presentation and not all patients respond to first-line treatments. Several neurocircuit models of OCD have been proposed with the aim of providing a better understanding of the neural and cognitive mechanisms involved in the disorder. These models use advances in neuroscience and findings from neuropsychological and neuroimaging studies to suggest links between clinical profiles that reflect the symptoms and experiences of patients and dysfunctions in specific neurocircuits. Several models propose that treatments for OCD could be improved if directed to specific neurocircuit dysfunctions, thereby restoring efficient neurocognitive function and ameliorating the symptomatology of each associated clinical profile. Yet, there are several important limitations to neurocircuit models of OCD. The purpose of the current review is to highlight some of these limitations, including issues related to the complexity of brain and cognitive function, the clinical presentation and course of OCD, etiological factors, and treatment methods proposed by the models. We also provide suggestions for future research to advance neurocircuit models of OCD and facilitate translation to clinical application.
Assuntos
Transtorno Obsessivo-Compulsivo , Cognição , Comportamento Compulsivo , Humanos , Neuroimagem , Comportamento Obsessivo , Transtorno Obsessivo-Compulsivo/diagnósticoRESUMO
Obsessive-compulsive disorder (OCD) is a common psychiatric condition classically characterized by obsessions (recurrent, intrusive and unwanted thoughts) and compulsions (excessive, repetitive and ritualistic behaviors or mental acts). OCD is heterogeneous in its clinical presentation and not all patients respond to first-line treatments. Several neurocircuit models of OCD have been proposed with the aim of providing a better understanding of the neural and cognitive mechanisms involved in the disorder. These models use advances in neuroscience and findings from neuropsychological and neuroimaging studies to suggest links between clinical profiles that reflect the symptoms and experiences of patients and dysfunctions in specific neurocircuits. Several models propose that treatments for OCD could be improved if directed to specific neurocircuit dysfunctions, thereby restoring efficient neurocognitive function and ameliorating the symptomatology of each associated clinical profile. Yet, there are several important limitations to neurocircuit models of OCD. The purpose of the current review is to highlight some of these limitations, including issues related to the complexity of brain and cognitive function, the clinical presentation and course of OCD, etiological factors, and treatment methods proposed by the models. We also provide suggestions for future research to advance neurocircuit models of OCD and facilitate translation to clinical application.
RESUMO
A growing body of evidence suggests that the mode of movement selection is relevant for the readiness potential, namely, internal (or free) selection of movements is associated with increased readiness potential amplitudes compared to predetermined or externally guided selection. It is little acknowledged, however, that this finding may be ascribed to the different expression of volition (i.e., conscious experience of choice) rather than to the mode of movement selection per se. To probe this issue, we conducted two experiments: in Experiment 1, a mental task was employed to distract sixteen volunteers from the selection and performance of incidental movements, which consisted of pressing one of two buttons according to either free or externally guided modes of movement selection; in Experiment 2, another sixteen individuals performed the same motor task, however, they were encouraged to attend to their intention to act. As result, the increased readiness potential amplitude before freely selected movements was found exclusively in Experiment 2. More detailed analysis suggested that the attention to the initiation of movements was associated with greater readiness potential in its medial and late portion, while the attention to the movement selection, with more global increase of the component. The study suggests that much of the higher demands on motor preparatory activities ascribed to the internal selection of movements in previous studies actually depends on individual's attention and, thus, probably corresponds to volitional processes.