Figure 6. Electrophysiological characteristics of BC-4.

BC-4 is morphologically characterized by the spread of its axonal arbour across the sublayers 1 and 2 of the IPL (A). After recording, its identity was immunohistochemically confirmed by calsenilin (Csen) labelling (B, arrow). Increasingly depolarizing voltage steps caused first inward and subsequently outward currents with a large amount of synaptic noise, but no evident Na⁺ currents (C). Hyperpolarization triggered non-inactivating inward currents insensitive to both nifedipine and ZD 7288, suggesting the presence of I_Kir currents (D). In response to glutamate, a fast initial response is followed by a slowly developing secondary component under voltage clamp (E). Together with inhibitory feedback (F), this generates a complex triphasic response under current clamp (G).