In the current scientific work, violations of the cerebral circulation of laboratory animals with diabetes mellitus and metabolic syndrome have been studied. Changes in the density of the vascular network of the pial membrane of the sensorimotor cortex, dilation of the pial arteries, tissue perfusion, and oxygen saturation were considered. The studied rats were kept on a high-fat diet for 60 days, as a result of which the animals had an increase in blood glucose levels, the development of insulin resistance, and a significant set of visceral fat. The metabolic syndrome led to changes in cerebral circulation, tissue perfusion decreased by 22%, and oxygen saturation decreased by 6%. The development of type 2 diabetes mellitus leads to dysfunction of the endothelium of the cerebral arteries: the smaller the diameter of the vessel, the worse the expansion reaction to acetylcholine. It was found that the emptying of the vascular bed, and impaired reactivity of the cerebral arteries negatively affect the supply of oxygen to brain tissues.