A composition comprises organoborane amine complex and 1,4-dioxo-2-butene-functional material. or above, contains no aromatic ring, has a molecular size of no greater than 50 and is soluble in the developing solution for the resist, at 1-50 parts by weight with respect to 100 parts by solid weight of the resist, as well as a pattern forming process employing it. Such a multilayered head is compact and easier to fabricate than heads made with unitary construction. The insertion hole portion is disposed between the mounting hole portion and the side edge of the printed wiring board. When cultured in the presence of RA and the absence of FGF, NRP cells differentiate into GABAergic, glutaminergic, and cholinergic immunoreactive neurons.