Autistic children may not find voices pleasurable due to a weak connection between the part of the brain responsible for speaking and the region dedicated to reward.

Brain imaging showed connections between the two brain regions were much stronger in children without autism, the finding makes sense because communication problems are one of the main struggles associated with autism, according to Bloomberg.com.

The study looked at 20 autistic children who were considered to be "high functioning" and compared their scans with those of 19 non-autistic children of similar intelligence. The autistic children had a weaker connection between the temporal lobe, which controls speech and the "dopamine reward pathway that elicits pleasurable feelings."

The study also noticed there was a weaker link between the region of the brain controlling voice, and the region controlling emotional responses.

"There isn't a lot of data to strongly point at what are the root causes of the social deficits in children with autism," Daniel Abrams, a postdoctoral fellow at Stanford University in California, said. "We think it has this important motivation and reward component to it."

Sensitivity to human speech can play an important role in early development. Infants are often stimulated by voices, helping them to bond with their family members and develop "early language skills and emotional understanding."

Autistic children do not naturally respond to human voices in the same way, they need to be encouraged to associate speech with reward. According to experts, overcoming this obstacle could help to make the wiring in the brain stronger.

"Some of the very first observations for children with autism are often that these kids are unresponsive to human speech," Abrams said.

Future studies hope to find out if there are any particular parts of the voice that activate an autistic child's brain more so than others. One in 50 U.S. children are autistic; the amount of children diagnosed with autism has increased by 72 percent over the past six or seven years.

"People are really working hard on this and making some cool findings," Abrams said.