Research Fellows Directory
Dr Jeremy Niven
University of Sussex
Much of what we consider makes us unique in comparison to other species is determined by our large brains. Our behaviour and cognition are the product of our large brains. Indeed, our relatively large brains are thought to be key to our success. Thus, brain size is thought to be linked to behaviour and cognition. Although the relationship between brain size and body mass in mammal has been known for many years, we know far less about brain size in the very smallest animals. Our recent studies have shown that the very tiniest insects and spiders have relatively huge brains for their body mass. Indeed, tiny spiders have brains so large that they have expanded into the legs. In one species, there is even a pronounced bulge in the exoskeleton to accommodate the large brain.
Energy is consumed by neurons in the brain to process information. Our evolution is thought to be linked to providing sufficient energy to our hungry brains, which consume 20% of our resting metabolism. Neurons send messages between them, which are needed to generate behaviour. It is these messages, encoded as small electrical pulses called action potentials, which are thought consume a substantial amount of the energy. We have recently calculated how much energy these electrical pulses consume in many different neurons, showing that they consume different amounts of energy. Although some action potentials are very expensive, consuming far more energy than they need to, others use almost the least energy they possibly can. These neurons are found in the brains of mammals, including our own. This enabled us to revise energy budgets for the brain. Understanding the energy consumption of different neurons is key not just for understanding the evolution of our brains and those of other animals but also for interpreting brain imaging, which is essential for medical diagnoses.
Interests and expertise (Subject groups)