Perceived controllability modulates the neural response to pain Salomons, et al.
The perception of pain is influenced by many factors, some of which have nothing to do with the physical stimulus itself, as anyone who has feared a trip to the dentist can attest. In this issue Salomons et al. used fMRI to examine how perceived control of a painful stimulus changes the perception of pain. During brain imaging, subjects used a joystick that they were told could reduce the duration of a painful thermal stimulus. However, this control was illusory because the physical stimulus remained constant. Nonetheless most subjects reported that they had reduced the length of the painful stimulus under the "controllable" condition.
2. Neuronal nicotinic receptor antibodies and autonomic neuropathy
Passive transfer of autoimmune autonomic neuropathy to mice
Vernino, et al.
Several classical neurological disorders involve autoimmune-mediated disruption of peripheral synapses, the best known being myasthenia gravis that is caused by circulating antibodies to the muscle nicotinic receptor. In this issue, Vernino et al. examine such a disease mechanism in a disorder involving peripheral autonomic ganglia, autoimmune autonomic neuropathy (AAN). The authors injected mice with IgG from rabbits immunized with an alpha-3 fusion protein to test a requirement for an antibody-mediated disorder: passive transfer. The recipient mice had impaired cholinergic ganglionic transmission and signs of autonomic failure. Likewise, mice injected with serum from human AAN patients also developed a similar phenotype.
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