Using a numerical model, a study of the sensitivity of the general atmospheric circulation to changes in solar activity (SA) in the thermosphere was performed. The study uses a model of the middle and upper atmosphere MUAM. To achieve sufficient statistical confidence, the global atmospheric circulation is simulated on the basis of two ensembles of 16 model runs, taking into account low and high SA above 100 km. It is shown that SA fluctuations contribute to a change in the mean zonal wind and temperature in the middle atmosphere up to 10%. The most interesting conclusion is that the effect of changes in SA in the thermosphere above 100 km can significantly affect the dynamic and thermal regime at altitudes below 100 km, due to changes in the waveguide features of the atmosphere. These simulation results are important for further understanding the mechanisms of the influence of SA on the dynamics of the middle atmosphere.