Dr. James Stone, who authored the research, says that the signaling between these two types of neurotransmitter is happening between a part of the brain called the hippocampus and another called the striatum.

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Hancock says he found great inspiration and freedom in the music of James Brown and Sly Stone, and sought to incorporate some of funk's distinct sounds and rhythms into his group.

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Other big summer stars include Tom Hanks in Larry Crowne, Kevin James in Zookeeper and Emma Stone in the film adaptation of The Help.

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