Fig. 8. The position of the postero-medial barrel subfield (PMBSF) is not shifted in PAX77 cortex but its size is reduced. (A) Tangential sections through one cortical hemisphere of P7 wild-type and PAX77^+/+ mice stained with anti-serotonin transporter. The primary somatosensory (S1), auditory (A1) and visual (V1) areas are revealed. (B) Measurements of the ratio between the distance of barrel c4 from the rostral pole of the cortex (R, black arrow) and the total length of the cortex (T, white arrow). No significant difference was found between wild-type and PAX77 mice (Student's t-test, n=16). (C) Measurement of the ratio between the distance of barrel c4 from the caudal pole of the cortex (C, black arrow) and the total length of the cortex (T, white arrow). No significant difference was found between wild-type and PAX77 mice (Student's t-test, n=16). (D) Measurement of the ratio between the area of the PMBSF (Pa) and the total area of the cortex (Ca). ^**Area of PMBSF relative to the total cortical area was significantly reduced in the PAX77 brain compared with wild type (Student's t-test, P<0.01, n=13 wild-type brains and 8 PAX77^+/+ brains). Scale bars: 1 mm.