Publications by authors named "Carlos V Rizzo Sierra"

The content of the rectified motor evoked potential (MEP) induced by transcranial magnetic stimulation (TMS) has ambiguously been assessed without the precision that energy calculation deserves. This fact has misled data interpretation and misguided biomedical interventions. To definitively fill the gap that exits in the neurophysics processing of these signals, we computed, in the within the rectified MEP recorded from the human first digitorum index (FDI) muscle at rest and under isometric contraction.

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Myasthenia gravis is a paradigmatic muscle disorder characterized by abnormal fatigue and muscle weakness that worsens with activities and improves with rest. Clinical and research studies done on nicotinic acetylcholine receptors have advanced our knowledge of the muscle involvement in myasthenia. Current views still state that sensory deficits are not "features of myasthenia gravis".

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Objective: The jiggle of the motor evoked potential (MEP) induced by transcranial magnetic stimulation (TMS) depends on a number of factors including the assessment of this stochastic signal by the method known as area under curve (AUC). We aim to ascertain the MEP findings assessed by the AUC method obtained from individuals affected by lesions at different levels of the neuroaxis.

Methods: We systematically search and critically appraise the scientific reports publishing on the MEP obtained from individuals with hypo- or hyperkinetic disorders of the neural system, and dissect the neurophysical assessment of the obtained data.

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Motion sickness or kinetosis is the result of the abnormal neural output originated by visual, proprioceptive and vestibular mismatch, which reverses once the dysfunctional sensory information becomes coherent. The space adaptation syndrome or space sickness relates to motion sickness; it is considered to be due to yaw, pith, and roll coordinates mismatch. Several behavioural and pharmacological measures have been proposed to control these vestibular-associated movement disorders with no success.

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A sonar based device with tactile feedback was developed to improve the mobility and independence of visually impaired individuals. It features a transceiver/receiver, a potentiometer, a microcontroller, a rechargeable polymer lithium ion battery, and a Nokia Cell phone vibrator. All components are commercially available and housed in a custom acrylic package with 86 mm × 34 mm × 12 mm in dimension, and 120 grms in weight.

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Background And Aims: The motor-evoked potential (MEP) induced by transcranial magnetic stimulation (TMS), its recruitment and the conditioning effects of weak stimuli in Parkinson's disease (PD) have shown contradictory results. The aim of this study is to definitively establish the influences of PD on the TMS-evoked MEP.

Methods: We investigated resting and active motor thresholds, resting and active recruitment curves, and short interval intracortical inhibition (ICI) and facilitation (ICF) in 39 PD patients and 40 age-matched healthy controls.

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The highly sensitive trait present in animals, has also been proposed as a human neurobiological trait. People having such trait can process larger amounts of sensory information than usual, making it an excellent attribute that allows to pick up subtle environmental details and cues. Furthermore, this trait correlates to some sort of giftedness such as higher perception, inventiveness, imagination and creativity.

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This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.

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Current research is in agreement with the presence of a magnetic compass in living beings including humans. The two most accepted explanations that demonstrate the existence of magnetoreceptors in living beings are, the radical pair and the biogenic magnetite, which are discussed here with its respective experimental evidence and support. It indicates the presence of magnetite crystals in otoliths, among different inferior species of animals.

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A recent methodological approach for human classification, diagnosis, and therapeutics through the combination of current Western constitutional psychology somatotypes and traditional Indian medicine (prakriti) body types and mind (manas) is herein presented. The striking similarities between psychologic somatotypes and Indian medicine body types permits proposal of a finite genopsycho-somatotyping of humans. Genopsycho-somatotyping of humans consists of a set of common physiologic, physical, and psychologic attributes related to a common basic birth constitution that remains somewhat permanent during human lifetime, since it is proposed that this birth constitution is programmed in the person's DNA (genes).

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Despite theoretical and experimental efforts to understand the space adaptation syndrome (SAS), which is responsible for spatial disorientation that severely affects physical and cognitive performance in astronauts, most of its pathophysiology is still unknown. As a consequence, countermeasures for SAS are not completely effective. Accordingly, in addition to the sensory-motor conflict theories, we propose that microgravity would affect the potassium channels of inner ear hair cells that would result in a temporal channelopathy as the most likely molecular origin for SAS, as well as being responsible for perpetuating movement disorders in gravity transition environments including those to be experienced by people visiting or living on the earth, moon, mars and beyond.

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A method to reduce the acoustic noise generated by gradient systems in MRI has been recently proposed; such a method is based on the linear response theory. Since the physical cause of MRI acoustic noise is the time derivative of the gradient current, a common trapezoid current shape produces an acoustic gradient coil response mainly during the rising and falling edge. In the falling edge, the coil acoustic response presents a 180 degrees phase difference compared to the rising edge.

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Functional magnetic resonance imaging (fMRI) enables sites of brain activation to be localized in human subjects. For auditory system studies, however, the acoustic noise generated by the scanner tends to interfere with the assessments of this activation. Understanding and modeling fMRI acoustic noise is a useful step to its reduction.

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