Large-scale coupling of prefrontal activity patterns as a mechanism for cognitive control in health and disease: evidence from rodent models.

Cognitive control of behavior is crucial for well-being, as allows subject to adapt to changing environments in a goal-directed way. Changes in cognitive control of behavior is observed during cognitive decline in elderly and in pathological mental conditions. Therefore, the recovery of cognitive control may provide a reliable preventive and therapeutic strategy. However, its neural basis is not completely understood. Cognitive control is supported by the prefrontal cortex, structure that integrates relevant information for the appropriate organization of behavior. At neurophysiological level, it is suggested that cognitive control is supported by local and large-scale synchronization of oscillatory activity patterns and neural spiking activity between the prefrontal cortex and distributed neural networks. In this review, we focus mainly on rodent models approaching the neuronal origin of these prefrontal patterns, and the cognitive and behavioral relevance of its coordination with distributed brain systems. We also examine the relationship between cognitive control and neural activity patterns in the prefrontal cortex, and its role in normal cognitive decline and pathological mental conditions. Finally, based on these body of evidence, we propose a common mechanism that may underlie the impaired cognitive control of behavior.

Enhanced Astrocyte Activity and Excitatory Synaptic Function in the Hippocampus of Pentylenetetrazole Kindling Model of Epilepsy.

Epilepsy is a chronic condition characterized by recurrent spontaneous seizures. The interaction between astrocytes and neurons has been suggested to play a role in the abnormal neuronal activity observed in epilepsy. However, the exact way astrocytes influence neuronal activity in the epileptogenic brain remains unclear. Here, using the PTZ-induced kindling mouse model, we evaluated the interaction between astrocyte and synaptic function by measuring astrocytic Ca2+ activity, neuronal excitability, and the excitatory/inhibitory balance in the hippocampus. Compared to control mice, hippocampal slices from PTZ-kindled mice displayed an increase in glial fibrillary acidic protein (GFAP) levels and an abnormal pattern of intracellular Ca2+-oscillations, characterized by an increased frequency of prolonged spontaneous transients. PTZ-kindled hippocampal slices also showed an increase in the E/I ratio towards excitation, likely resulting from an augmented release probability of excitatory inputs without affecting inhibitory synapses. Notably, the alterations in the release probability seen in PTZ-kindled slices can be recovered by reducing astrocyte hyperactivity with the reversible toxin fluorocitrate. This suggests that astroglial hyper-reactivity enhances excitatory synaptic transmission, thereby impacting the E/I balance in the hippocampus. Altogether, our findings support the notion that abnormal astrocyte-neuron interactions are pivotal mechanisms in epileptogenesis.

Alteraciones de la masticación en usuarios de prótesis dental removible. Revisión sistemática / Chewing alterations in removable dental prosthesis users: systematic review

Resumen:Tras el paso de los años, la pérdida de dientes genera la necesidad de recurrir al uso de prótesis dental. Específicamente, las alteraciones en el proceso de masticación en usuarios de prótesis dental removible se consideran un problema no sólo en relación a las modificaciones a nivel morfofuncional, sino que también en la propia satisfacción en cuanto a la masticación y funcionalidad de este proceso. El propósito de esta revisión es compilar y analizar los artículos científicos sobre la relación de la masticación y prótesis dental removible en adultos y adultos mayores. Se realizó una búsqueda integrativa de artículos en las bases de datos SCIELO, LILACS y PUBMED, seleccionando artículos publicados entre el año 2005 a 2014. Los artículos de revisión incluyeron estudios que identificaran la relación entre el uso de prótesis dental removible y la masticación en adultos usuarios de dicha prótesis dental. En la búsqueda se encontraron 21 documentos para potencial revisión. Finalmente, aplicando criterios de inclusión y exclusión se seleccionaron11artículos, los cuales tomaban diferentes variables de estudio, entre ellas, nivel de satisfacción, rendimiento, eficiencia y parámetros masticatorios. La satisfacción, el rendimiento, la eficiencia y los parámetros masticatorios fueron las variables que se encontraban afectadas en usuarios de prótesis dental removible.

Abstract:In aging process, the tooth loss generates the need to use a dental prosthesis. Specific alterations in mastication process of denture-users can be considered a problem not only in relation to the morphofunctional structures modification, but also in personal satisfaction associated to chewing and its functionality. The proposal of this review is to compile and analyze scientific articles about the relation between chewing and removable dental prostheses in adults and older adult's users. An integrative search of all articles on data from SCIELO, PUBMED and LILACS databases selected articles published 2006 to 2014, whose topic focused mastication and removable dental prosthesis in adults. The search presented 21 potential articles and, after applying criteria of inclusion and exclusion, 11 were selected. The satisfaction, performance, efficiency and masticatory parameters were the variables, which found to be effected in users of removable dental prosthesis.