The Journal of neuroscience : the official journal of the Society for Neuroscience
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Randomized Controlled Trial
Static Magnetic Field Stimulation over the Visual Cortex Increases Alpha Oscillations and Slows Visual Search in Humans.
Transcranial static magnetic field stimulation (tSMS) was recently introduced as a promising tool to modulate human cerebral excitability in a noninvasive and portable way. However, a demonstration that static magnetic fields can influence human brain activity and behavior is currently lacking, despite evidence that static magnetic fields interfere with neuronal function in animals. ⋯ The typical relationship between prestimulus alpha power over posterior cortical areas and reaction time (RT) to targets during tSMS is altered such that tSMS-dependent increases in alpha power are associated with longer RTs for difficult, but not easy, target detection trials. Our results directly demonstrate that a powerful magnet placed on the scalp modulates normal brain activity and induces behavioral changes in humans.
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Randomized Controlled Trial
Neural Substrates for Head Movements in Humans: A Functional Magnetic Resonance Imaging Study.
The neural systems controlling head movements are not well delineated in humans. It is not clear whether the ipsilateral or contralateral primary motor cortex is involved in turning the head right or left. Furthermore, the exact location of the neck motor area in the somatotopic organization of the motor homunculus is still debated and evidence for contributions from other brain regions in humans is scarce. ⋯ Electromyographic recordings of neck and hand muscles during scanning ensured compliance with the tasks. Increased brain activity during isometric head rotation was observed bilaterally in the precentral gyrus, both medial and lateral to the hand area, as well the supplementary motor area, insula, putamen, and cerebellum. These findings clarify the location of the neck region in the motor homunculus and help to reconcile some of the conflicting results obtained in earlier studies.
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Randomized Controlled Trial
Reduction of empathy for pain by placebo analgesia suggests functional equivalence of empathy and first-hand emotion experience.
Previous research in social neuroscience has consistently shown that empathy for pain recruits brain areas that are also activated during the first-hand experience of pain. This has been interpreted as evidence that empathy relies upon neural processes similar to those underpinning the first-hand experience of emotions. However, whether such overlapping neural activations imply that equivalent neural functions are engaged by empathy and direct emotion experiences remains to be demonstrated. ⋯ Moreover, these effects were specific for pain, as self-report and ERP measures of control conditions unrelated to pain were not affected by placebo analgesia. Together, the present results suggest that empathy seems to rely on neural processes that are (partially) functionally equivalent to those engaged by first-hand emotion experiences. Moreover, they imply that analgesics may have the unwanted side effect of reducing empathic resonance and concern for others.