Primary and secondary brain tumors are a constant challenge for the medicine. Tissue sensitivity to ionizing radiation differs and depends on numerous factors and the same dose of radiation may produce different effects in particular structures of the CNS. It can also affect the surrounding healthy tissues and lead to adverse effects like the cognitive or physical function impairment. One of brain structures most sensitive to ionizing radiation is the limbic system, especially the hippocampus, because it is here that the postnatal neurogenesis takes place via neural stem cells, which are a self-renewing population of precursor cells. There have been no studies that would thoroughly examine the impact of different CNS radiation therapy techniques on the cognitive function, potential neuroplasticity markers or blood-brain barrier damage in brain tumor patients with a concomitant use of neurocognitive combination therapies or physical exercise, and their impact on the CNS function. The aim of the study is to assess the impact of selected RT techniques: IMRT, WBRT, and CyberKnife (SRS) on the processes regulating cognitive and physical function in patients with primary (Group III and IV, WHO, 2016) and metastatic CNS tumors. The secondary objective is the analysis of the effect of selected forms of neurorehabilitation on the parameters studied. The study will be a prospective clinical trial conducted in 150 patients. Patient evaluation will be carried out before RT, after RT, during a follow-up visit-3 months after RT, and finally after 6 months. The methods will be used: analysis of the blood-brain barrier permeability markers including exact connection proteins, markers confirming neuroplasticity of the brain, cerebral secretory activity, and onco- and anti-neuronal antibody activity, brain structure analysis (MRI) and volume testing of selected brain structures, and assessment of cognitive and physical function of the patients. The study will be a part of the search trend aiming to explain the mechanism of the formation of cognitive-behavioral disorders in humans based on the most fundamental principles governing information processing in CNS, and the impact of neoplasia and ionizing radiation on selected brain structures and functions. The results of the study might become a starting point for the formulation of new guidelines on the level of physical activity or cognitive exercise in patients treated with CNS radiation therapy.