The brain - the final frontier. Radio 4 is setting out on an exploration of the creative mind.

Gerald Scarfe's drawings have intrigued and alarmed for more than fifty years but where do his ideas come from? Professor Vincent Walsh of the Institute of Cognitive Neuroscience has a theory he wants to pursue. Vincent is an expert in the workings of the visual brain; he thinks that two specific areas may be talking to each other in an unexpected way, resulting in recognisable faces being mixed up with recognisable objects, hence Mrs Thatcher as an axe, a handbag, and even a shark.

Now, cartoonist and neuroscientist are going to meet. "I for one would be fascinated to know what's going on in my brain - please pursue this," says Gerald Scarfe.

The producer in Bristol is Miles Warde.