Inhalation of 7.5% CO2 increases anxiety and autonomic arousal in humans, and elicits fear behavior in animals. However, it is not known whether CO2 challenge in humans induces dysfunction in neurocognitive processes that characterize generalized anxiety, notably selective attention to environmental threat. Healthy volunteers completed an emotional antisaccade task in which they looked toward or away from (inhibited) negative and neutral stimuli during inhalation of 7.5% CO2 and air. CO2 inhalation increased anxiety, autonomic arousal, and erroneous eye movements toward threat on antisaccade trials. Autonomic response to CO2 correlated with hypervigilance to threat (speed to initiate prosaccades) and reduced threat inhibition (increased orienting toward and slower orienting away from threat on antisaccade trials) independent of change in mood. Findings extend evidence that CO2 triggers fear behavior in animals via direct innervation of a distributed fear network that mobilizes the detection of and allocation of processing resources toward environmental threat in humans.Don't worry--at current rates of emission increases (~0.7%/yr) this won't happen until the 28th century...but just imagine how good it will be for the plants!
-- M. Garner et al, Neuropsychopharmacology (2011) 36, 1557–1562
Wednesday, June 15, 2011
Our Terrifying Far-Future in a Carbon-rich World
If and when atmospheric carbon dioxide levels reach 75,000 ppm, we are in big, big trouble!
Posted by David Appell at 6/15/2011 05:22:00 PM