University of Michigan (US) scientists have identified specific breakdowns in brain connections that slow reaction times as we age.  Rachael Seidler and colleagues have identified an age-related breakdown affecting the corpus callosum, the part of the brain that modulates cross-talk between the two hemispheres of the brain.  The team has shown that cross-talk happens even while older adults are at rest; but this resting cross-talk is now shown to hinder response times and thus may contribute to confusion. The researchers observe that: “We suggest that reduced interhemispheric connectivity reflects a loss of the ability to inhibit the non-dominant hemisphere during motor task performance for older adults, which has a negative impact on performance.”