  We describe the operation of a neuronal device which embodies the
computational principles of the `paper-and-pencil' machine envisioned by Alan
Turing. The network is based on principles of cortical organization. We develop
a plausible solution to implement pointers and investigate how neuronal
circuits may instantiate the basic operations involved in assigning a value to
a variable (i.e., x=5), in determining whether two variables have the same
value and in retrieving the value of a given variable to be accessible to other
nodes of the network. We exemplify the collective function of the network in
simplified arithmetic and problem solving (blocks-world) tasks.
