Neural cultures

A method for producing a homogeneous population of neural cells which method comprises:

• a) enhancing the replication of an undifferentiated first neural cell with an immortalizing oncogene including, or having associated therewith, a control means responsive to temperature;
• and
• b) exposing said replicated first neural cell of step a) to an environment by an in vitro incubation step which is selected from the group consisting of:
• (i) incubation in the presence of mitotically active primary cells obtained from the same region of the central nervous system from which said first neural cell came;
• and
• (ii) incubation in the presence of an extract of mitotically active primary cells obtained from the same region of the central nervous system from which said first neural cell came:
• said incubation of said neural cell being carried out to produce fully differentiated active neural cells, committed to a single neural phenotype, but maintaining any replicative drive of undifferentiated neural cells by not raising the temperature to a non-permissive temperature of said oncogene control means.