The study is going to include 20 adolescents, 5-10 years after onset of T1D, aged 12-20 years, on insulin pump. The participants are going to have MRI of the head in euglycaemic and hyperglycaemic state. During both MRI, the participants are going to preform Flanker test, Tower of London test and Spatial memory test. The investigators are going to evaluate the response of inflammation markers and oxidative stress marekers in blood during hypreglycaemia.