A 2020 study conducted on the brains of eight male Russian cosmonauts after they returned from long stays aboard the International Space Station showed that long-duration spaceflight causes many physiological adaptions, including macro- and microstructural changes.
ɐ tˈuː θˈaʊzənd twˈɛnti stˈʌdi kəndˈʌktᵻd ɔnðə bɹˈeɪnz ʌv ˈeɪt mˈeɪl ɹˈʌʃən kˈɑːzmənˌɔːts ˈæftɚ ðeɪ ɹᵻtˈɜːnd fɹʌm lˈɔŋ stˈeɪz ɐbˈoːɹd ðɪ ˌɪntɚnˈæʃənəl spˈeɪs stˈeɪʃən ʃˈoʊd ðæt lˈɔŋdʊɹɹˈeɪʃən spˈeɪsflaɪt kˈɔːzᵻz mˈɛni fˌɪzɪəlˈɑːdʒɪkəl ɐdˈæpʃənz, ɪŋklˈuːdɪŋ mˈækɹoʊ ænd mˌaɪkɹoʊstɹˈʌktʃɚɹəl tʃˈeɪndʒᵻz.