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Fidias E Leon-Sarmiento

Publications and source records attributed to Fidias E Leon-Sarmiento.

9 recordsLinked to original sources
PubMed2005

Visual deprivation effects on human motor cortex excitability.

Single and paired-pulse transcranial magnetic stimulation (TMS) were applied to the motor cortex of 12 healthy volunteers, who were instructed to relax under eyes-open and eyes-closed conditions with room lights on and after 30 min of blindfolding. Compared to the eyes-open condition, significantly larger motor-evoked potentials and less intracortical inhibition were observed during blindfolding. Visual deafferentation changes resting human motor cortex excitability and might be a novel way to promote brain plasticity. These results raise the issue of how widespread the effects of temporary deafferentation may be and whether they are mediated by discrete or diffuse systems. These findings also illustrate an important potential confound in TMS studies of the motor cortex.

Darkness↗
PubMed2005

Capsaicin effects on blinking.

Blinking is a normal human phenomenon involving trigeminal and facial pathways. To gain understanding on the neurobiology of blinking, five normal subjects were investigated before and after application of transdermal capsaicin at the forehead for two weeks. No effects of topical capsaicin were detected in eye blink rates. However, when capsaicin was applied to a female subject with blepharospasm, she showed a dramatic restoration of her vision subsequent to blinking modification. Deactivation of abnormal A-to-C fibers cross talks at the trigeminal-facial pathways seems to be the most likely mechanism of such improvement.

Blepharospasm↗
PubMed2004

Trypanosoma cruzi-associated cerebrovascular disease: a case-control study in Eastern Colombia.

Trypanosoma cruzi infection is a common cause of cardiopathy in South America leading it eventually to an established stroke; however, the association between T. cruzi infection itself and cerebrovascular disease is still unknown. We did a case-control study at Eastern Colombia and found that T. cruzi infection was more frequent and statistically significant in stroke cases (24.4%) than controls (1.9%), (Chi square: 21.72; OR: 16.13; 95% confidence interval (CI): 3.64-71.4; p<0.00001). After removing the seropositive patients with cardiological abnormalities, the significance still remained by multivariate analysis (p<0.05). This is the first case-control study that demonstrated a significant link between this infection and symptomatic cerebrovascular disease, mainly ischemic, regardless of cardiac abnormalities. Therefore, we recommend that patients with stroke must be screened for T. cruzi infection if they currently live or have lived in places where this parasite is considered endemic.

Age Factors↗
PubMed2003

Repetitive transcranial magnetic stimulation (rTMS): new tool, new therapy and new hope for ADHD.

Attention-deficit hyperactivity disorder (ADHD) is the most common developmental disorder that is associated with environmental and genetic factors. Neurobiological evidence suggests that fronto-striatum-cerebellum circuit abnormalities, mainly in the right hemisphere, are responsible for most of the disturbed sensorimotor integration; dopamine seems to be the main neurochemical alteration underlying these morphological abnormalities. Different conventional treatments have been employed on ADHD; however, repetitive transcranial magnetic stimulation (rTMS), a new and useful option for the clinical/research investigation of several neuropsychiatric disorders involving dopamine circuits, has yet to be considered as a therapeutic tool and possible drug-free option for ADHD. Here the authors explore the available evidence that makes this tool a rational therapeutic possibility for patients with ADHD, calling attention to safety issues, while highlighting the potentials of such an approach and the new hope it may bring for patients, parents, researchers and clinicians. The authors advocate carefully conducted clinical trials to investigate efficacy, safety, cost-effectiveness and clinical utility of rTMS for ADHD patients - in comparison to both placebo and standard treatments.

Attention Deficit Disorder with Hyperactivity↗
PubMedDate not supplied

[Colciencias and disdain for Colombian scientists: from the Stone Age to the impact factor].

Writing has dramatically evolved in the world; however, qualification of scientific production in Colombia has not, including the improper use of decree 1444/93 and 1279/02. The last of these decrees authorized Colciencias, the Colombian government institute created to support scientific research in Colombia, to establish rules for its implementation. Colciencias decided to evaluate scientific papers produced in Colombia based on the non-scientific method of the "impact factor", and considered that citations in MEDLINE/PubMed and PsylNFO were second line publications thus violating Colombian law. This affects not only the progress of scientific research in Colombia but also researchers' income and puts Colombia's scientific journals and publications at great disadvantage. Scientific papers indexed in qualified databases such as MEDLINE/PubMed must be judged according to law in order to prevent further injuries to the developing Colombian scientific production.

Attitude↗