London: Researchers have discovered that two neurons in the brain hold the key to explaining how complex behavioural decisions are made. In this study, scientists monitored the snails' behaviour while they made decisions in their search for food. "Our study reveals for the first time how just two neurons can create a mechanism in an animal's brain which drives and optimises complex decision making tasks," said lead researchers George Kemenes, Professor at the University of Sussex in Britain. They then measured the activity in the snail's brain by using electrodes to record small electrical changes, called action potentials, in individual neurons. The results showed a controller type neuron which lets the snail's brain know potential food is present and a second neuron which transmits signals telling the snail's brain what it's motivational state is, i.e., whether it's hungry or not. Also, the system created by the neurons was found to enable the snails to save energy by reducing brain activity when food is not available. "The findings can help scientists to identify other core neuronal systems which underlie similar decision making processes," Kemenes added in the paper published in the journal Nature Communications. "The study will eventually help us design the 'brains' of robots based on the principle of using the fewest possible components necessary to perform complex tasks," Kemenes concluded.