[1] Univ Warwick, Sch Life Sci, Neurosci, Coventry CV4 7AL, W Midlands, England
[2] Univ Warwick, MIBTP, Coventry CV4 7AL, W Midlands, England
[3] Univ Calabar, Fac Basic Med Sci, Dept Anat, Calabar, Nigeria
[4] Ahmadu Bello Univ, Dept Biol Sci, Zaria, Nigeria