International journal of psychophysiology : official journal of the International Organization of Psychophysiology
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Int J Psychophysiol · Jul 2014
Disturbances in affective touch in hereditary sensory & autonomic neuropathy type III.
Hereditary sensory and autonomic neuropathy type III (HSAN III, Riley-Day syndrome, Familial Dysautomia) is characterised by elevated thermal thresholds and an indifference to pain. Using microelectrode recordings we recently showed that these patients possess no functional stretch-sensitive mechanoreceptors in their muscles (muscle spindles), a feature that may explain their lack of stretch reflexes and ataxic gait, yet patients have apparently normal low-threshold cutaneous mechanoreceptors. The density of C-fibres in the skin is markedly reduced in patients with HSAN III, but it is not known whether the C-tactile afferents, a distinct type of low-threshold C fibre present in hairy skin that is sensitive to gentle stroking and has been implicated in the coding of pleasant touch are specifically affected in HSAN III patients. ⋯ Conversely, for the patients, ratings of pleasantness did not fit the profile for C-tactile afferents. Patients either rated the higher velocities as more pleasant than the slow velocities, with the slowest velocities being rated unpleasant, or rated all velocities equally pleasant. We interpret this to reflect absent or reduced C-tactile afferent density in the skin of patients with HSAN III, who are likely using tactile cues (i.e. myelinated afferents) to rate pleasantness of stroking or are attributing pleasantness to this type of stimulus irrespective of velocity.
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Int J Psychophysiol · Jul 2014
Randomized Controlled TrialTracking EEG changes in response to alpha and beta binaural beats.
A binaural beat can be produced by presenting two tones of a differing frequency, one to each ear. Such auditory stimulation has been suggested to influence behaviour and cognition via the process of cortical entrainment. However, research so far has only shown the frequency following responses in the traditional EEG frequency ranges of delta, theta and gamma. ⋯ EEG was recorded from the left and right temporal regions during pre-exposure baselines, stimulus exposure epochs and post-exposure baselines. Analysis of changes in broad-band and narrow-band amplitudes, and frequency showed no effect of binaural beat frequency eliciting a frequency following effect in the EEG. Possible mediating factors are discussed and a number of recommendations are made regarding future studies, exploring entrainment effects from a binaural beat presentation.
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Int J Psychophysiol · Mar 2014
How friendly is a little friendly competition? Evidence of self-interest and empathy during outcome evaluation.
Although previous studies have shown that brain potentials recorded from passive observers differ when gambling-task outcomes are delivered to a friend or a stranger, it is unclear how these outcome evaluations are reflected in brain potentials during active competition. The present study recorded event-related potentials (ERP) from 16 normal adults playing an interactive gambling task against both a friend and a stranger. In this task, the P300 was modulated by the feedback valence (gain or loss) and the nature of the interpersonal relationship, such that it was larger when competing against strangers. ⋯ The dFRN, defined as the difference between losses and gains, varied with Perspective-Taking when competing against friends, such that smaller dFRN amplitudes were correlated with increased Perspective-Taking. The modulation of ERP components indicates that interpersonal relationships may influence outcome evaluations in competitive situations. Correlations between ERP components and empathy measures also provide preliminary support of a relationship between one's empathy and the processing of outcomes during competition against a friend.
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Int J Psychophysiol · Nov 2013
Brain oscillation and connectivity during a chemistry visual working memory task.
Many studies have reported that frontal theta and posterior alpha activities are associated with working memory tasks. However, fewer studies have focused on examining whether or not the frontal alpha or posterior theta can play a role in the working memory task. This study investigates electroencephalography (EEG) dynamics and connectivity among different brain regions' theta and alpha oscillations. ⋯ Study of the central parietal and the occipital clusters revealed a sequence of theta augmentation followed by alpha suppression at constant intervals after the onset of stimulus and probe presentations, suggesting that the posterior theta might be associated with sensory processing, theta gating, or stimulus selection. It further suggests that the posterior alpha event-related de-synchronization (ERD) might be linked to direct information flow into and out of the long-term memory (LTM) and precede stimulus recognition. An alternating phasic alpha event-related synchronization (ERS) and ERD following the 1st stimulus and probe presentations were observed at the occipital cluster, in which alpha ERS might be linked to the inhibition of irrelevant information.
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Int J Psychophysiol · Nov 2013
Mindfulness (Vipassana) meditation: effects on P3b event-related potential and heart rate variability.
The concept of mindfulness is based on Vipassana, a Buddhist meditation technique. The present study examines the physiological indices of attention and autonomic regulation in experienced Vipassana meditators to test the claim that mindfulness is an effective therapeutic tool due to its effects on increasing awareness of present experience and emotional self-regulation. Ten male experienced Vipassana meditators underwent two assessment sessions, one where they practiced Vipassana meditation and another where they rested with no meditation (random thinking). ⋯ The Vipassana experts showed greater P3b amplitudes to the target tone after meditation than they did both before meditation and after the no-meditation session. They also showed a larger LF/HF ratio increase during specific Vipassana meditation. These results suggest that expert Vipassana meditators showed increased attentional engagement after meditation and increased autonomic regulation during meditation supporting, at least partially, the two claims concerning the clinical effectiveness of mindfulness.