Brain/CS question

So, the human brain has a lot of folds on the surface. I was told in school that the number of folds is correlated to animal intelligence.

One common explanation is that its due to increased surface area somehow. But neurons do not cross the area between two folds. So therefore, there must be some benefit to having regions where less interconnection of neurons improves intelligence.

Perhaps the computer science construct of a neutral network would benefit from having one or more layers of less then fully connected perceptrons. This would reduce the amount of calculations needed for both forward and backward propagation.