... índices de lateralização. No futuro, ela será combinada com outras técnicas demapeamento func... more ... índices de lateralização. No futuro, ela será combinada com outras técnicas demapeamento functional, tais como a tratografia, o EEG intracraniano, ea magnetoencefalogragia, para produzir mapas multi-modalidade. Em vez de ...
... The burst was followed by a slow afterhyperpolarisation that stopped the spontaneous firing. ... more ... The burst was followed by a slow afterhyperpolarisation that stopped the spontaneous firing. A brief barrage of inhibitory synaptic potentials (MP, arrow) preceded the burst and was temporally correlated with the increase in background activity before the negative sharp wave. ...
The dorsolateral and medial prefrontal cortex are critical for immediate memory processing. The p... more The dorsolateral and medial prefrontal cortex are critical for immediate memory processing. The possibility has been raised that those two areas may also contribute to long-term memory formation. Here, we studied the role of specific receptors in dorsolateral and medial prefrontal cortex in immediate and in long-term memory formation of one-trial inhibitory avoidance. Four different specific receptor ligands were infused into these two areas: the dopamine D1 receptor antagonist, SCH23390, the GABA(A) receptor agonist, muscimol, the AMPA glutamatergic receptor antagonist, ciano-nitro-quinoxaline-dione (CNQX), and the NMDA glutamatergic receptor antagonist, aminophosphonovaleric acid (AP5). In all cases the doses used had been previously shown to affect immediate or long-term memory. In the experiments on immediate memory the drugs were given 5 min before training and the animals were tested 3s post-training. These animals were then also tested 24h later for long-term memory. The effect of the treatments on long-term memory was studied by their infusion 0, 90, 180 or 270 min post-training, testing the animals 24h after training. Immediate memory was inhibited by SCH23390, muscimol and CNQX, but not by AP5, given into any of the two subregions. Long-term memory formation was inhibited by SCH23390, muscimol and CNQX, but not by AP5, given pre-training or 0, 90 or 180 but not 270 min post-training into the dorsolateral region; or 90 but not 0 or 180 min post-training into the medial region. Thus, there is a time- and receptor-dependent correlation in the two areas between their role in immediate and in long-term memory processing. Both roles require intact glutamate AMPA and dopamine D1 receptors, are inhibited by GABAergic synapses, and are unaffected by AP5. In the dorsolateral prefrontal cortex the link between immediate and long-term memory appears to be direct; in the medial area the link suffers a 90 min delay.
Epilepsia partialis continua (EPC) is a life-threatening condition often caused by focal cortical... more Epilepsia partialis continua (EPC) is a life-threatening condition often caused by focal cortical dysplasia (FCD). Resection of the motor cortex is contemplated in the hope that the trade-off between a severe motor deficit and complete seizure control justifies the procedure. Report of 3 patients with EPC due to histologically confirmed FCD, who underwent resection of the motor cortex under acute electrocorticography. All had re-emergence of medically intractable EPC in the other side of the body after rolandic resection. Two patients died and the third continues with refractory attacks. In some instances, EPC due to FCD may shift sides and re-emerge in the contralateral, previously asymptomatic, hemibody. A mechanism of disinhibition by surgery of a suppressed contralateral and homologous epileptogenic zone is speculated.
Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiologic entity not yet under... more Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiologic entity not yet understood, that presents with transient neurologic symptoms and particular radiological findings. Few papers show the differences between pregnant and non-pregnant patients. We review the cases of 38 women diagnosed with PRES, in order to find significant differences between pregnant (18) and non-pregnant (20) patients. We found differences among the age of patients (25.83 years old in pregnant and 29.31 years old in non pregnant; P=0.001); in the mean of highest systolic blood pressure, that was higher in non-pregnant group (185:162 mmHg; P=0.121); and in creatinine levels that was higher in non-pregnant group (3.47:1.04 mg/dL; P=0.001). To our knowledge, just a few papers analyzed whether PRES syndrome presented in the same way in pregnant and non-pregnant patients. The differences and the possible pathophisiology of this syndrome still remain enigmatic.
Recent advances in neuroimaging techniques have resulted in more frequent detection of unruptured... more Recent advances in neuroimaging techniques have resulted in more frequent detection of unruptured intracranial aneurysms. Regardless of the method employed, most interventions to treat lesions have low morbidity and mortality rates. Recently, some studies have suggested that changes in cognitive status are one complication of microsurgical treatments. However, no study to date has performed any behavioral analysis. Moreover, cognitive assessment beyond 12 months after surgical intervention is missing. The current study sought to evaluate the long-term impact of clipping on the behavioral and cognitive functions of patients with unruptured intracranial aneurysms. A within-subjects prospective clinical trial was performed to evaluate 40 patients who underwent microsurgical clipping for incidental unruptured intracranial aneurysms. The participants underwent a full neuropsychological evaluation during the preoperative period, at 3 months after surgery and at 3 years after surgery. Paired Student's t tests and an ANOVA, followed by a Bonferroni post hoc test, were used to examine group differences. The cognitive and behavioral test performance of the patients did not deteriorate during either the short or the long term following intervention. Moreover, the patients' clinical and demographic characteristics did not predict behavioral or cognitive changes, and neither the surgical approach nor the topography, multiplicity, or size of the aneurysms affected the results. In either the short or the long term following clipping for patients with incidental unruptured intracranial aneurysms, behavioral and cognitive functions had no significant change from baseline. The intervention demonstrated high efficacy and was associated with a low morbidity rate.
To evaluate electroencephalogram (EEG) patterns in very low birth weight premature newborns when ... more To evaluate electroencephalogram (EEG) patterns in very low birth weight premature newborns when reaching term-to-term neonates, thereby comparing extra uterine to intra uterine development. EEG recordings were obtained between 2 and 14 days of life in 47 preterm (<37 weeks) very low birth weight (⩽1500 g) newborns and repeated when reaching term age (38-42 weeks) in a subsample (n=22). EEG recordings were also obtained in term newborns. Clinical evaluation was performed at birth and at 6 and 12 months. Relative to the first EEG, preterm newborns showed a reduction in delta brushes and interburst intervals and increased interhemispheric synchrony, suggesting an improvement in EEG maturation. Further organization in sleep patterns, like a reduction in total sleep time and phase shifts, were also observed. However, when reaching term, preterm newborns still had less mature EEG patterns, phase shifts and transitional sleep than matched controls. Background abnormalities and dysmaturity in preterm newborns during the first EEG predicted adverse neurological outcome later on. EEG patterns in preterm very low birth weight newborns might be influenced by extra uterine development. Specific EEG abnormalities are related to increased risk of neurological disorders. Extra uterine development of very low birth weight delays the acquisition of maturational EEG patterns.
... índices de lateralização. No futuro, ela será combinada com outras técnicas demapeamento func... more ... índices de lateralização. No futuro, ela será combinada com outras técnicas demapeamento functional, tais como a tratografia, o EEG intracraniano, ea magnetoencefalogragia, para produzir mapas multi-modalidade. Em vez de ...
... The burst was followed by a slow afterhyperpolarisation that stopped the spontaneous firing. ... more ... The burst was followed by a slow afterhyperpolarisation that stopped the spontaneous firing. A brief barrage of inhibitory synaptic potentials (MP, arrow) preceded the burst and was temporally correlated with the increase in background activity before the negative sharp wave. ...
The dorsolateral and medial prefrontal cortex are critical for immediate memory processing. The p... more The dorsolateral and medial prefrontal cortex are critical for immediate memory processing. The possibility has been raised that those two areas may also contribute to long-term memory formation. Here, we studied the role of specific receptors in dorsolateral and medial prefrontal cortex in immediate and in long-term memory formation of one-trial inhibitory avoidance. Four different specific receptor ligands were infused into these two areas: the dopamine D1 receptor antagonist, SCH23390, the GABA(A) receptor agonist, muscimol, the AMPA glutamatergic receptor antagonist, ciano-nitro-quinoxaline-dione (CNQX), and the NMDA glutamatergic receptor antagonist, aminophosphonovaleric acid (AP5). In all cases the doses used had been previously shown to affect immediate or long-term memory. In the experiments on immediate memory the drugs were given 5 min before training and the animals were tested 3s post-training. These animals were then also tested 24h later for long-term memory. The effect of the treatments on long-term memory was studied by their infusion 0, 90, 180 or 270 min post-training, testing the animals 24h after training. Immediate memory was inhibited by SCH23390, muscimol and CNQX, but not by AP5, given into any of the two subregions. Long-term memory formation was inhibited by SCH23390, muscimol and CNQX, but not by AP5, given pre-training or 0, 90 or 180 but not 270 min post-training into the dorsolateral region; or 90 but not 0 or 180 min post-training into the medial region. Thus, there is a time- and receptor-dependent correlation in the two areas between their role in immediate and in long-term memory processing. Both roles require intact glutamate AMPA and dopamine D1 receptors, are inhibited by GABAergic synapses, and are unaffected by AP5. In the dorsolateral prefrontal cortex the link between immediate and long-term memory appears to be direct; in the medial area the link suffers a 90 min delay.
Epilepsia partialis continua (EPC) is a life-threatening condition often caused by focal cortical... more Epilepsia partialis continua (EPC) is a life-threatening condition often caused by focal cortical dysplasia (FCD). Resection of the motor cortex is contemplated in the hope that the trade-off between a severe motor deficit and complete seizure control justifies the procedure. Report of 3 patients with EPC due to histologically confirmed FCD, who underwent resection of the motor cortex under acute electrocorticography. All had re-emergence of medically intractable EPC in the other side of the body after rolandic resection. Two patients died and the third continues with refractory attacks. In some instances, EPC due to FCD may shift sides and re-emerge in the contralateral, previously asymptomatic, hemibody. A mechanism of disinhibition by surgery of a suppressed contralateral and homologous epileptogenic zone is speculated.
Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiologic entity not yet under... more Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiologic entity not yet understood, that presents with transient neurologic symptoms and particular radiological findings. Few papers show the differences between pregnant and non-pregnant patients. We review the cases of 38 women diagnosed with PRES, in order to find significant differences between pregnant (18) and non-pregnant (20) patients. We found differences among the age of patients (25.83 years old in pregnant and 29.31 years old in non pregnant; P=0.001); in the mean of highest systolic blood pressure, that was higher in non-pregnant group (185:162 mmHg; P=0.121); and in creatinine levels that was higher in non-pregnant group (3.47:1.04 mg/dL; P=0.001). To our knowledge, just a few papers analyzed whether PRES syndrome presented in the same way in pregnant and non-pregnant patients. The differences and the possible pathophisiology of this syndrome still remain enigmatic.
Recent advances in neuroimaging techniques have resulted in more frequent detection of unruptured... more Recent advances in neuroimaging techniques have resulted in more frequent detection of unruptured intracranial aneurysms. Regardless of the method employed, most interventions to treat lesions have low morbidity and mortality rates. Recently, some studies have suggested that changes in cognitive status are one complication of microsurgical treatments. However, no study to date has performed any behavioral analysis. Moreover, cognitive assessment beyond 12 months after surgical intervention is missing. The current study sought to evaluate the long-term impact of clipping on the behavioral and cognitive functions of patients with unruptured intracranial aneurysms. A within-subjects prospective clinical trial was performed to evaluate 40 patients who underwent microsurgical clipping for incidental unruptured intracranial aneurysms. The participants underwent a full neuropsychological evaluation during the preoperative period, at 3 months after surgery and at 3 years after surgery. Paired Student's t tests and an ANOVA, followed by a Bonferroni post hoc test, were used to examine group differences. The cognitive and behavioral test performance of the patients did not deteriorate during either the short or the long term following intervention. Moreover, the patients' clinical and demographic characteristics did not predict behavioral or cognitive changes, and neither the surgical approach nor the topography, multiplicity, or size of the aneurysms affected the results. In either the short or the long term following clipping for patients with incidental unruptured intracranial aneurysms, behavioral and cognitive functions had no significant change from baseline. The intervention demonstrated high efficacy and was associated with a low morbidity rate.
To evaluate electroencephalogram (EEG) patterns in very low birth weight premature newborns when ... more To evaluate electroencephalogram (EEG) patterns in very low birth weight premature newborns when reaching term-to-term neonates, thereby comparing extra uterine to intra uterine development. EEG recordings were obtained between 2 and 14 days of life in 47 preterm (<37 weeks) very low birth weight (⩽1500 g) newborns and repeated when reaching term age (38-42 weeks) in a subsample (n=22). EEG recordings were also obtained in term newborns. Clinical evaluation was performed at birth and at 6 and 12 months. Relative to the first EEG, preterm newborns showed a reduction in delta brushes and interburst intervals and increased interhemispheric synchrony, suggesting an improvement in EEG maturation. Further organization in sleep patterns, like a reduction in total sleep time and phase shifts, were also observed. However, when reaching term, preterm newborns still had less mature EEG patterns, phase shifts and transitional sleep than matched controls. Background abnormalities and dysmaturity in preterm newborns during the first EEG predicted adverse neurological outcome later on. EEG patterns in preterm very low birth weight newborns might be influenced by extra uterine development. Specific EEG abnormalities are related to increased risk of neurological disorders. Extra uterine development of very low birth weight delays the acquisition of maturational EEG patterns.
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