In one of the first such studies involving human patients with schizophrenia, researchers at UC Davis have provided evidence that deficits in a brain chemical may be responsible for some of the debilitating cognitive deficits ? poor attention, memory and problem-solving abilities ? that accompany the delusions and hallucinations that are the hallmarks of the disorder.The study, published online March 10 in the Journal of Neuroscience, suggests an important avenue of inquiry for improving cognitive function in the more than 2 million Americans who suffer from schizophrenia, according to Jong H.