Diurnal variation of NMDA receptor expression in the rat cerebral cortex is associated with traumatic brain injury damage.

OBJECTIVE: Data from our laboratory suggest that recovery from a traumatic brain injury depends on the time of day at which it occurred. In this study, we examined whether traumatic brain injury -induced damage is related to circadian variation in N-methyl-D-aspartate receptor expression in rat cortex. RESULTS: We confirmed that traumatic brain injury recovery depended on the time of day at which the damage occurred. We also found that motor cortex N-methyl-D-aspartate receptor subunit NR1 expression exhibited diurnal variation in both control and traumatic brain injury-subjected rats. However, this rhythm is more pronounced in traumatic brain injury-subjected rats, with minimum expression in those injured during nighttime hours. These findings suggest that traumatic brain injury occurrence times should be considered in future clinical studies and when designing neuroprotective strategies for patients.

The Role of the IntraoperativeAuxiliaryMethods in the Resection of Motor Area Lesions / O papel dos métodos auxiliares intraoperatórios na ressecção de lesões em área motora

Objective In recent years, technologies have advanced considerably in improving surgical outcome following treatment of lesions in eloquent brain areas. The aimof this study is to explore which method is best in the resection of motor area lesions. Methods Prospective, non-randomized study Evaluate on 74 patients who underwent surgery to remove lesions around the motor area. Results Total lesion removal was achieved in 68 patients (93.1%). Fifty-four patients (73.9%) presented normal motor function in the preoperative period; of these, 20 (37.3%) developed transitory deficits. Nevertheless, 85% of these patients later experienced a complete recovery. Nineteen patients presented with motor deficits preoperatively; of these, five presented deteriorating motor abilities. Intraoperative stimulation methods were used in 65% of the patients, primarily in cases of glioma. Conclusions The morbidity in patients submitted to resections of motor area lesions is acceptable and justify the surgical indication with the purpose of maximal resection. Intraoperative stimulation is an important tool that guides glioma resection in many cases.

Objetivo Nos últimos anos, consideráveis avanços tecnológicos têm surgido no sentido de melhorar os resultados cirúrgicos no tratamento de lesões em áreas eloquentes do cérebro. O objetivo deste estudo é investigar qual o melhor método para ressecção de lesões em área motora. Método Estudo prospectivo não aleatório que avaliou os resultados pós-operatórios em 74 pacientes submetidos à ressecção de lesões em área motora ou adjacente. Resultados A ressecção cirúrgica foi considerada total em 68 (93,1%) pacientes. 54 pacientes (73,9%) apresentavam força muscular normal no pré-operatório. Destes, 20 (37,3%) apresentaram déficit no pós-operatório imediato, sendo que 17 (85%) recuperaram completamente o déficit. 19 pacientes apresentavam déficit no préoperatório, sendo que 05 apresentaram piora do déficit no pós-operatório imediato. A estimulação intraoperatória foi utilizada em 65% dos casos, principalmente nos gliomas. Conclusão Amorbidade empacientes operados de lesões emáreamotora é bastante aceitável e justifica a indicação cirúrgica com objetivo de ressecção máxima. A estimulação intraoperatória é uma ferramenta importante para guiar a resseção dos gliomas em muitos casos.

Pontine and cerebellar norepinephrine content in adult rats recovering from focal cortical injury.

Norepinephrine (NE) plays an important role in motor recovery after brain damage. Most studies concerning NE activity have been performed in the cerebellum, while the role of the pons, the site where the norepinephrinergic locus coeruleus is located, has not yet been elucidated. For this work, we studied the changes in cerebellar and pontine NE content in sham-operated (n = 17), motor cortex injured (n = 6) and recovered rats (n = 12). Motor effects were assessed by means of footprint analysis and sensorimotor evaluation. It was found that after cortical brain damage, the stride length decreases while the stride angle increases after 6 h post-surgery, while the sensorimotor evaluation showed an increase in the motor deficit. Recovery was observed after 24 h. NE content increased in the pons after 6 h and returned to normal levels in recovered rats, with no significant changes observed in the cerebellum. Based on the functional remote inhibition, it is possible that NE exerts an autoinhibitory effect in the pons after motor cortical ablation. On the other hand, the absence of an effect in the cerebellum suggests that cerebellar NE activity related to damage and/or recovery is limited to discrete areas of the structure.

[Cortical plasticity and restoration of neurologic functions: an update on this topic]. / Plasticidad cortical y restauración de funciones neurológicas: una actualización sobre el tema.

INTRODUCTION: Neuroplasticity is a natural property of the nervous system to change its function and to reorganize due to a lesion or environmental changes. We review some of the main experimental and clinical experiences on cortical sensorimotor plasticity related to central nervous system (CNS) lesions. DEVELOPMENT: In the last 10 years increasing interest in neuronal plasticity has been prompted by several important discoveries. Long term potentiation and depression have been described as basic synaptic mechanism mediating functional recovery after CNS lesions, modulated by the up-down regulation of inhibitory-excitatory activity related to GABA, acetylcholine and glutamate between other neurotransmitters. In humans there are evidences from functional reorganization in the affected hemisphere in patients with hemispheric lesions, and the activation of homologues areas in the contralateral healthy hemisphere. Significative changes in the topography of cortical somatosensory and motor maps have been demonstrated using non invasive mapping techniques as multichannel EEG, evoked potential, transcranial magnetic stimulation, functional magnetic resonance imaging and positron emission tomography. Axonal and dendritic sprouting take place in animal models of brain lesions; but effective neural regeneration in the CNS does not seem to be a plausible mechanism for functional restoring. CONCLUSIONS: Plastic changes after CNS lesions make it possible the restoration of neurological functions in a high number of patients. It is important now to understand which changes are related to the clinical improvement of patients, and what might be done to promote or facilitate this changes and to inhibit maladaptive phenomena, for the design of rationale therapeutics strategies with modulatory influence on this process.