It is widely appreciated, from observational studies of children in the classroom and controlled experiments in animals, that using multiple senses aids learning and improves later memory. While it was known that cross-talk between the brain’s various sensory cortices likely supports this phenomenon, there was no mechanistic explanation for how such an interaction could occur and how memory could be enhanced by such a process.
To identify these neural mechanisms, Dr Zeynep Okray and Dr Pedro Jacob (Centre for Neural Circuits and Behaviour, Department of Physiology, Anatomy & Genetics) developed a novel multisensory learning paradigm where fruit flies learn to associate an odour, a colour, or a combination of the two, with a reward or punishment. They found that learning and later memory retrieval were improved when multiple senses were engaged.
The researchers studied the fly’s neuronal responses using cutting-edge optical recording techniques and found that training with odours and colours together altered subsequent responses to these sensory cues in learning-relevant neurons. Surprisingly, visual-selective cells became activatable by the learned odour, whereas odour-selective cells became responsive to the learned colours. These changes in neural responsiveness in effect permit the flies to conjure a mental representation of the whole memory from only partial information.