Tomás Ortiz

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Visual aesthetic perception ("aesthetics") or the capacity to visually perceive a particular attribute added to other features of objects, such as form, color, and movement, was fixed during human evolutionary lineage as a trait not shared with any great ape. Although prefrontal brain expansion is mentioned as responsible for the appearance of such human(More)
CONTEXT Neuropsychological models of depression highlight temporoparietal hypofunction associated with low emotional arousal in major depressive disorder (MDD). These models were derived from indirect measures such as neuropsychological tests and electroencephalography alpha band power. OBJECTIVE To determine if high-arousing stimuli directly modulated(More)
The present report studied the magnetic counterpart (CMV) of the auditory contingent negative variation (CNV). The ear where the target auditory stimulus would be presented was cued with a visual central arrow at a validity of 84%. The subject's behavioral response and the magnetoencephalographic (MEG) and electroencephalographic (EEG) signals were(More)
BACKGROUND Patients suffering from Alzheimer's disease exhibit more activity in the conventional electroencephalographic delta and theta bands. This activity concurs with atrophy and reduced metabolic and perfusion rates, particularly in temporoparietal structures. METHODS Whole-head magnetoencephalographic recordings were obtained from 15 patients(More)
The capacity to appreciate beauty is one of our species' most remarkable traits. Although knowledge about its neural correlates is growing, little is known about any gender-related differences. We have explored possible differences between men and women's neural correlates of aesthetic preference. We have used magnetoencephalography to record the brain(More)
OBJECTIVE The neurodevelopmental-neurodegenerative debate is a basic issue in the field of the neuropathological basis of schizophrenia (SCH). Neurophysiological techniques have been scarcely involved in such debate, but nonlinear analysis methods may contribute to it. METHODS Fifteen patients (age range 23-42 years) matching DSM IV-TR criteria for SCH,(More)
OBJECTIVE In this study, we applied a novel procedure to calculate the mean frequency from the Magnetoencephalography (MEG) signals of 22 patients with Alzheimer's Disease (AD), 22 patients with mild cognitive impairment (MCI), and 21 healthy controls. A significant mean frequency decrease was expected in pathological groups. MCI subjects are expected to(More)
Magnetoencephalography (MEG) allows the real-time recording of neural activity and oscillatory activity in distributed neural networks. We applied a non-linear complexity analysis to resting-state neural activity as measured using whole-head MEG. Recordings were obtained from 20 unmedicated patients with major depressive disorder and 19 matched healthy(More)
BACKGROUND AND PURPOSE Patients with Alzheimer disease (AD) have more low-frequency activity on conventional EEG and increased focal magnetoencephalographic (MEG) dipole density (DD) in delta and theta bands. This activity concurs with atrophy and reduced metabolic and perfusion rates, particularly in temporoparietal structures. The relationship between(More)
Over three months of intensive training with a tactile stimulation device, 18 blind and 10 blindfolded seeing subjects improved in their ability to identify geometric figures by touch. Seven blind subjects spontaneously reported 'visual qualia', the subjective sensation of seeing flashes of light congruent with tactile stimuli. In the latter subjects(More)