Specific alterations of cerebral hemodynamics during a planning task: a transcranial Doppler sonography study

Planning plays an important role in daily activities, and several experimental paradigms have been investigated with brain imaging methods showing activity in putative brain regions such as dorsolateral prefrontal cortex and other frontal and non-frontal regions. The Stockings of Cambridge (SOC), a related procedure to the Tower of London task, was introduced to 21 healthy subjects while they underwent bilateral transcranial Doppler sonography (TCD) of the middle (MCA) and anterior (ACA) cerebral arteries. Different levels of difficulty were applied during continuous registration of peak mean cerebral blood flow velocity (CBFV). A specific test procedure allowed separating the actual planning from the execution phase. There was also a similar control task, which did not involve planning. CBFV differed among the planning, execution, and control conditions (MCA: P < 0.01; ACA: P < 0.001), but did not show a significant difference between the MCA and ACA (P > 0.1). Easy tasks yielded a more rapid increase of CBFV in the MCA compared to difficult problems during planning (P < 0.05). In conclusion, our findings of specific CBFV patterns support the idea of different cognitive challenges for planning and control and between easy and difficult conditions.