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Neuroscience For Kids

Railroad Workers Exposed to Neurotoxic Chemicals
November 4, 2006


Railroad workers who clean equipment with certain chemicals may be damaging their brains. Scientists have known that people who sniff inhalants often show brain damage to myelin, the insulation around a neuron's axon. Railroad workers who degrease locomotives and train parts are sometimes cc exposed to inhalants such as cleaning chemicals (solvents). Researchers led by Dr. Marc W. Haut at West Virginia University School of Medicine investigated whether these railroad workers also had damage to their brains. The scientists focused their study on the corpus callosum, the thick band of 200 million axons that connects the right and left hemispheres of the brain.


Dr. Haut and his colleagues measured the volume of the corpus callosum in 31 railroad workers who had been working with solvents for an average of 8.44 years. These workers were often exposed to more than one gallon of solvent per day without the use of personal protective equipment such as gloves or a respirator. A group of 31 people who were of similar age, education, IQ, height and weight as the railroad workers were used as a control group.

The total volume of the corpus callosum was found to be significantly smaller in railroad workers compared to that in the train control group. This difference was mainly due to a decrease in the volume of the anterior (front) part of corpus callosum. Also, railroad workers who had more exposure to solvents had smaller volumes of their corpus callosum (total size and anterior segment). People with a smaller corpus callosum also did more poorly on cognitive tests such as the Stroop Color-Word Test.


The anterior part of the corpus callosum sends axons to the prefrontal cortex. This area of the brain is involved many complex behaviors such as attention, planning, problem solving and personality. Damage to this area of the corpus callosum could affect a person's ability to think properly and may be responsible for the poor cognitive performance of the railroad workers exposed to the chemicals. The Occupational Safety and Health Administration (OSHA) has strict rules about exposure to solvents. Let's hope that railroad workers can follow these rules to avoid possible damage to their brains.

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