Biomedical subjects

J J González-Rosa

Publications and source records attributed to J J González-Rosa.

3 recordsLinked to original sources

PubMed2005

Alternate response preparation in a visuomotor serial task.

The preparation of a particular motor pattern is related to the information available that enables the actor to predict the correct response to a forthcoming stimulus. In many situations, however, prediction is not possible. In such cases, the individual can guess the probable parameters of the next stimulus. The authors attempted to establish the bias in the motor intention for movement and its interaction with a possible memory trace of the stimulus-response mapping produced by the preceding stimulus. Two letters were presented bilaterally, and participants (N=21) had to discriminate the target letter and respond with the compatible hand. The present findings support the existence of a memory trace of the previous stimulus-response mapping.

Adult↗

PubMed2004

Task-specific sensory and motor preparatory activation revealed by contingent magnetic variation.

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 recorded. The central cue diminished reaction times (RTs) to the auditory target in the valid conditions with respect to the invalid conditions, indicating that the attentional manipulation was effective. The averaged magnetic field power during the preparatory period was significantly higher than baseline, suggesting the simultaneous presence of a magnetic counterpart of the electric CNV--the CMV. The field maps of the CMV grand averages showed two different and well-established periods: an early one with a magnetic field distribution that suggests a central source, and a late one with a field topography comparable to a low-intensity auditory-evoked field (M1). Single-dipole analysis of the preparatory phase in the subject's magnetic resonance images (MRI) demonstrated the presence of dipolar activity in the posterior cingulate (PCC) and posterior parietal cortices (PPC), superior temporal gyrus (STG) and motor cortices (MC). The lateralization of this activity depended on the orientation of the central cue. These results suggest that the action and perceptual-related areas needed to process the expected subsequent imperative task are recruited during the preparatory periods, influencing the behavioral RTs.

Acoustic Stimulation↗

PubMedDate not supplied

[Gender-specific post-stimulus modulation in the alpha band during visual-spatial attention].

INTRODUCTION: Previous studies of the spontaneous activity of the EEG indicate that women present bigger absolute spectral power in the alpha band than men, but few studies have been done during cognitive activity. AIM: To check possible gender differences in the EEG frequency domain during a visuo-spatial attentional task to understand better the temporary dynamics of alpha. SUBJECTS AND METHODS: A classic oddball paradigm was used whose stimuli (90% standard-10% objectives) were complex. In each block (10 with 100 trials) it was requested to the subjects (20, 10 of each gender) to attend to one of the visual fields (left and right, with random stimuli and identical probability). Power spectral density values were calculated applying the fast Fourier transform in the alpha band (9-11 Hz) in two overlapped windows (sliding windows): of 0-512 ms and of 412-924 ms. RESULTS: The normalized data were analyzed by means of ANOVAs, with the following factors: gender, attention, hemisphere, visual field and electrodes. CONCLUSIONS: Different modulations were obtained attending to the gender variable: men showed smaller alpha or bigger suppression of the rhythm in posterior electrodes and women exhibited smaller power in anterior electrodes.

Attention↗