Normal nine and 10-year-olds from rich and poor backgrounds had differing electrical activity in a part of the brain linked to problem solving.

The Journal of Cognitive Neuroscience study was described as a "wake-up call" about the impact of deprivation.

A UK researcher said it could shed light on early brain development.

The 26 children in the study, conducted at the University of California, Berkeley, were measured using an electroencephalograph (EEG), which measured activity in the "prefrontal cortex" of the brain.

Half were from low income homes, and half from high income families.

During the test, an image the children had not been briefed to expect was flashed onto a screen, and their brain responses were measured.

Those from lower income families showed a lower prefrontal cortex response to it than those from wealthier households.