RESUMEN
Episodic memory is the ability to learn, store and recall new information. The prefrontal cortex (PFC) is a crucial area engaged in this ability. Cognitive training has been demonstrated to improve episodic memory in adults and older subjects. However, there are no studies examining the effects of cognitive training on episodic memory encoding in typically developing children and adolescents. This study investigated the behavioral effects and neural correlates of semantic categorization strategy training in children and adolescents during verbal episodic memory encoding using functional magnetic resonance imaging (fMRI). Participants with age range: 7-18 years were scanned before and after semantic categorization training during encoding of word lists. Results showed improved memory performance in adolescents, but not in children. Deactivation of the anterior medial PFC/anterior cingulate and higher activation of the right anterior and lateral orbital gyri, right frontal pole and right middle frontal gyrus activation were found after training in adolescents when compared to children. These findings suggest different maturational paths of brain regions, especially in the PFC, and deactivation of default mode network areas, which are involved in successful memory and executive processes in the developing brain.
Asunto(s)
Memoria Episódica , Semántica , Adolescente , Desarrollo del Adolescente/fisiología , Mapeo Encefálico , Niño , Desarrollo Infantil/fisiología , Cognición/fisiología , Femenino , Neuroimagen Funcional , Giro del Cíngulo/diagnóstico por imagen , Giro del Cíngulo/crecimiento & desarrollo , Giro del Cíngulo/fisiología , Humanos , Imagen por Resonancia Magnética , Masculino , Corteza Prefrontal/diagnóstico por imagen , Corteza Prefrontal/crecimiento & desarrollo , Corteza Prefrontal/fisiologíaRESUMEN
OBJECTIVE: Patients with obsessive-compulsive disorder (OCD) often present with deficits in episodic memory, and there is evidence that these difficulties may be secondary to executive dysfunction, that is, impaired selection and/or application of memory-encoding strategies (mediation hypothesis). Semantic clustering is an effective strategy to enhance encoding of verbal episodic memory (VEM) when word lists are semantically related. Self-initiated mobilization of this strategy has been associated with increased activity in the prefrontal cortex, particularly the orbitofrontal cortex, a key region in the pathophysiology of OCD. We therefore studied children and adolescents with OCD during uncued semantic clustering strategy application in a VEM functional magnetic resonance imaging (fMRI)-encoding paradigm. METHOD: A total of 25 pediatric patients with OCD (aged 8.1-17.5 years) and 25 healthy controls (HC, aged 8.1-16.9) matched for age, gender, handedness, and IQ were evaluated using a block design VEM paradigm that manipulated semantically related and unrelated words. RESULTS: The semantic clustering strategy score (SCS) predicted VEM performance in HC (p < .001, R(2) = 0.635), but not in patients (p = .099). Children with OCD also presented hypoactivation in the dorsomedial prefrontal cortex (cluster-corrected p < .001). Within-group analysis revealed a negative correlation between Yale-Brown Obsessive Compulsive Scale scores and activation of orbitofrontal cortex in the group with OCD. Finally, a positive correlation between age and SCS was found in HC (p = .001, r = 0.635), but not in patients with OCD (p = .936, r = 0.017). CONCLUSION: Children with OCD presented altered brain activation during the VEM paradigm and absence of expected correlation between SCS and age, and between SCS and total words recalled. These results suggest that different neural mechanisms underlie self-initiated semantic clustering in OCD.
Asunto(s)
Memoria Episódica , Trastorno Obsesivo Compulsivo/fisiopatología , Corteza Prefrontal/fisiopatología , Semántica , Adolescente , Mapeo Encefálico , Brasil , Niño , Estudios Transversales , Femenino , Humanos , Modelos Lineales , Imagen por Resonancia Magnética , MasculinoRESUMEN
In this study we examined differences in fMRI activation and deactivation patterns during episodic verbal memory encoding between individuals with MCI (n = 18) and healthy controls (HCs) (n = 17). Participants were scanned in two different sessions during the application of self-initiated or directed instructions to apply semantic strategies at encoding of word lists. MCI participants showed reduced free recall scores when using self-initiated encoding strategies that were increased to baseline controls' level after directed instructions were provided. During directed strategic encoding, greater recruitment of frontoparietal regions was observed in both MCI and control groups; group differences between sessions were observed in the ventromedial prefrontal cortex and the right superior frontal gyrus. This study provides evidence suggesting that differences of activity in these regions may be related to encoding deficits in MCI, possibly mediating executive functions during task performance.
RESUMEN
Gamma ventral capsulotomy (GVC) radiosurgery is intended to minimize side effects while maintaining the efficacy of traditional thermocoagulation techniques for the treatment of refractory obsessive-compulsive disorder (OCD). Neuropsychological outcomes are not clear based on previous studies and, therefore, we investigated the effects of GVC on cognitive and motor performance. A double-blind, randomized controlled trial (RCT) was conducted with 16 refractory OCD patients allocated to active treatment (n=8) and sham (n=8) groups. A comprehensive neuropsychological evaluation including intellectual functioning, attention, verbal and visuospatial learning and memory, visuospatial perception, inhibitory control, cognitive flexibility, and motor functioning was applied at baseline and one year after the procedure. Secondary analysis included all operated patients: eight from the active group, four from the sham group who were submitted to surgery after blind was broken, and five patients from a previous open pilot study (n=5), totaling 17 patients. In the RCT, visuospatial memory (VSM) performance significantly improved in the active group after GVC (p=0.008), and remained stable in the sham group. Considering all patients operated, there was no decline in cognitive or motor functioning after one year of follow-up. Our initial results after 1 year of follow-up suggests that GVC not only is a safe procedure in terms of neuropsychological functioning but in fact may actually improve certain neuropsychological domains, particularly VSM performance, in treatment refractory OCD patients.
Asunto(s)
Cápsula Interna/cirugía , Trastornos de la Memoria/etiología , Trastornos de la Memoria/cirugía , Trastorno Obsesivo Compulsivo/complicaciones , Radiocirugia/métodos , Percepción Espacial/fisiología , Adulto , Método Doble Ciego , Función Ejecutiva , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Trastorno Obsesivo Compulsivo/cirugía , Escalas de Valoración Psiquiátrica , Estadísticas no Paramétricas , Resultado del Tratamiento , Adulto JovenRESUMEN
UNLABELLED: Despite growing interest in developing cognitive training interventions to minimize the aging cognitive decline process, no studies have attempted to explore which brain regions support the application of semantic strategies during verbal memory encoding. Our aim was to investigate the behavioral performance and brain correlates of these strategies in elderly individuals using fMRI in healthy older subjects. METHOD: Subjects were scanned twice on the same day, before and after, directed instructions to apply semantic strategies during the encoding of word lists. RESULTS: Improved memory performance associated to increased semantic strategy application and brain activity in the left inferior and middle and right medial superior prefrontal cortex were found after the directed instructions. There was also reduced activation in areas related to strategy mobilization. CONCLUSION: Improved memory performance in older subjects after the application of semantic strategies was associated with functional brain reorganization involving regions inside and outside the typical memory network.
Asunto(s)
Envejecimiento/fisiología , Encéfalo/anatomía & histología , Encéfalo/fisiología , Cognición/fisiología , Memoria Episódica , Anciano , Mapeo Encefálico , Femenino , Estado de Salud , Humanos , Imagen por Resonancia Magnética , Masculino , Recuerdo Mental/fisiología , Pruebas Neuropsicológicas , Valores de Referencia , Semántica , Factores de Tiempo , Aprendizaje Verbal/fisiologíaRESUMEN
Despite growing interest in developing cognitive training interventions to minimize the aging cognitive decline process, no studies have attempted to explore which brain regions support the application of semantic strategies during verbal memory encoding. Our aim was to investigate the behavioral performance and brain correlates of these strategies in elderly individuals using fMRI in healthy older subjects. Method Subjects were scanned twice on the same day, before and after, directed instructions to apply semantic strategies during the encoding of word lists. Results Improved memory performance associated to increased semantic strategy application and brain activity in the left inferior and middle and right medial superior prefrontal cortex were found after the directed instructions. There was also reduced activation in areas related to strategy mobilization. Conclusion Improved memory performance in older subjects after the application of semantic strategies was associated with functional brain reorganization involving regions inside and outside the typical memory network. .
Apesar do crescente interesse em intervenções de treinamento cognitivo para minimizar o declínio cognitivo do envelhecimento, nenhum estudo explorou quais regiões do cérebro estão relacionadas à aplicação de estratégias semânticas durante a codificação da memória verbal. Nosso objetivo foi investigar o comportamento e correlatos cerebrais associados a essas estratégias usando fMRI em idosos saudáveis. Método Os sujeitos foram examinados no mesmo dia, antes e depois, de instruções dirigidas para aplicar estratégias semânticas durante a codificação de palavras. Resultados Melhora da memória relacionada ao uso de estratégias semânticas e aumento da atividade no córtex prefrontal inferior e medial esquerdo e medial superior direito foram encontrados após as instruções. Também houve redução de ativação em áreas de mobilização de estratégias. Conclusão A melhora da memória em idosos após o uso de estratégias semânticas estava associada à reorganização cerebral funcional envolvendo regiões dentro e fora da rede de áreas cerebrais típicas da memória. .
Asunto(s)
Anciano , Femenino , Humanos , Masculino , Envejecimiento/fisiología , Encéfalo/anatomía & histología , Encéfalo/fisiología , Cognición/fisiología , Memoria Episódica , Mapeo Encefálico , Estado de Salud , Imagen por Resonancia Magnética , Recuerdo Mental/fisiología , Pruebas Neuropsicológicas , Valores de Referencia , Semántica , Factores de Tiempo , Aprendizaje Verbal/fisiologíaRESUMEN
OBJECTIVE: Memory deficit is a frequent cognitive disorder following acquired prefrontal cortex lesions. In the present study, we investigated the brain correlates of a short semantic strategy training and memory performance of patients with distinct prefrontal cortex lesions using fMRI and cognitive tests. METHODS: Twenty-one adult patients with post-acute prefrontal cortex (PFC) lesions, twelve with left dorsolateral PFC (LPFC) and nine with bilateral orbitofrontal cortex (BOFC) were assessed before and after a short cognitive semantic training using a verbal memory encoding paradigm during scanning and neuropsychological tests outside the scanner. RESULTS: After the semantic strategy training both groups of patients showed significant behavioral improvement in verbal memory recall and use of semantic strategies. In the LPFC group, greater activity in left inferior and medial frontal gyrus, precentral gyrus and insula was found after training. For the BOFC group, a greater activation was found in the left parietal cortex, right cingulated and precuneus after training. CONCLUSION: The activation of these specific areas in the memory and executive networks following cognitive training was associated to compensatory brain mechanisms and application of the semantic strategy.
Asunto(s)
Encéfalo/fisiología , Trastornos de la Memoria/rehabilitación , Memoria/fisiología , Corteza Prefrontal/patología , Desempeño Psicomotor/fisiología , Adulto , Encefalopatías/psicología , Encefalopatías/rehabilitación , Encefalopatías/cirugía , Mapeo Encefálico , Neoplasias Encefálicas/complicaciones , Neoplasias Encefálicas/cirugía , Circulación Cerebrovascular , Imagen Eco-Planar , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Trastornos de la Memoria/etiología , Trastornos de la Memoria/psicología , Recuerdo Mental , Persona de Mediana Edad , Pruebas Neuropsicológicas , Oxígeno/sangre , Corteza Prefrontal/cirugía , SemánticaRESUMEN
OBJECTIVE: To evaluate brain activation in response to common food and nonfood logos in healthy weight and obese children. STUDY DESIGN: Ten healthy weight children (mean body mass index in the 50th percentile) and 10 obese children (mean body mass index in the 97.9th percentile) completed self-report measures of self-control. They then underwent functional magnetic resonance imaging while viewing food and nonfood logos. RESULTS: Compared with the healthy weight children, obese children showed significantly less brain activation to food logos in the bilateral middle/inferior prefrontal cortex, an area involved in cognitive control. CONCLUSION: When shown food logos, obese children showed significantly less brain activation than the healthy weight children in regions associated with cognitive control. This provides initial neuroimaging evidence that obese children may be more vulnerable to the effects of food advertising.
Asunto(s)
Encéfalo/fisiología , Alimentos , Obesidad/psicología , Adolescente , Índice de Masa Corporal , Peso Corporal , Encéfalo/metabolismo , Mapeo Encefálico/métodos , Niño , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Obesidad/fisiopatología , Padres , Reconocimiento Visual de Modelos , Proyectos Piloto , Corteza Prefrontal/fisiología , Encuestas y CuestionariosRESUMEN
The prefrontal cortex (PFC) has been implicated in the ability to apply semantic organizational strategies during verbal encoding and episodic learning. However, there has been no direct evidence demonstrating which specific areas in the PFC are engaged after cognitive training using semantic organizational strategies in healthy adult human subjects. In this study, we investigated the effects of semantic strategic training on brain activity and changes in behavioral performance, after cognitive training, using functional MRI (fMRI). There was a significant activation in bilateral dorsolateral prefrontal (DLPF) and orbitofrontal (OFC) areas after cognitive training. These results demonstrate the engagement of bilateral DLPF and OFC cortex during strategic memory processes, particularly when mobilization and effort of effective use of strategies are required. The functional adaptations observed here may also shed light on some of the processes underlying recovery with cognitive rehabilitation in patient populations with brain injury.
Asunto(s)
Lateralidad Funcional/fisiología , Aprendizaje/fisiología , Memoria/fisiología , Corteza Prefrontal/fisiología , Conducta Verbal/fisiología , Adulto , Mapeo Encefálico , Terapia Cognitivo-Conductual/métodos , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Red Nerviosa/anatomía & histología , Red Nerviosa/fisiología , Vías Nerviosas/anatomía & histología , Vías Nerviosas/fisiología , Pruebas Neuropsicológicas , Corteza Prefrontal/anatomía & histología , EnseñanzaRESUMEN
Retrospectiva. O transtorno obsessivo-compulsivo (TOC) é heterogênio, com algumas formas relacionadas à Síndrome de Gilles de la Tourette (SGT). Este é um estudo fenomenológico destinado a investigar a natureza desses possíveis subtipos de TOC e a relaçäo entre TOC e SGT. Método. Avaliamos 20 pacientes adultos ambulatoriais com TOC, 21 com SGT, e 20 com TOC + SGT, utilizando uma entrevista semi-estruturada para avaliar os fenômenos cognitivos, sensoriais e autonômicos, precedentes aos comportamentos repetitivos. Resultados. Foram relatados mais fenômenos cognitivos e ansiedade autonômica e menos fenômenos sensoriais no TOC que na SGT. Assim como no grupo de SGT, também no grupo de TOC e SGT foram relatados mais fenômenos sensoriais e menos cogniçöes que no grupo TOC. Conclusöes. A presença ou ausência de fenômenos cognitivos, fenômenos sensoriais e ansiedade autonômica distinguem os comportamentos repetitivos em pacientes com TOC daqueles com TOC + SGT, e SGT. Essas experiências subjetivas podem ser úteis em subclassificar o TOC e podem representar preditores válidos de prognóstico e resposta ao tratamento
Asunto(s)
Humanos , Masculino , Femenino , Adolescente , Adulto , Persona de Mediana Edad , Trastorno Obsesivo Compulsivo/psicología , Síndrome de Tourette/psicología , Ansiedad , Conducta Compulsiva , Trastornos de la Percepción , Trastornos de la SensaciónRESUMEN
RETROSPECTIVA. O transtorno obsessivo-compulsivo (TOC) e heterogeneo, com algumas formas relacionadas a Sindrome de Gilles de la Tourette (SGT). Este e um estudo fenomenologico destinado a investigar a natureza desses possiveis subtipos de TOC e a relacao entre TOC e SGT. METODO. Avaliamos 20 pacientes adultos ambulatoriais com TOC, 21 com SGT, e 20 com TOC + SGT, utilizando uma entrevista semi-estruturada para avaliar os fenomenos cognitivos, sensoriais e autonomicos, precedentes aos comportamentos repetitivos. RESULTADOS. Foram relatados mais fenomenos cognitivos e ansiedade autonomica e menos fenomenos sensoriais no TOC que na SGT. Assim como no grupo de SGT, tambem no grupo TOC e SGT foram relatados mais fenomenos sensoriais e menos cognicoes que no grupo TOC. CONCLUSOES. A presenca ou ausencia de fenomenos cognitivos, fenomenos sensoriais e ansiedade autonomica distinguem os comportamentos repetitivos em pacientes com TOC daqueles com TOC + SGT, e SGT. Essas experiencias subjetivas podem ser uteis em subclassificar o TOC e podem representar preditores validos de prognostico e resposta ao tratamento.