How engineers learn from the powerful circuits of insect brains – Professor Barbara Webb

However, scientists have discovered a small collection of brain cells in the insect’s tiny brain that forms the circuitry to efficiently calculate all the trigonometric functions needed for navigation.

This region of the insect’s brain, called the central complex, has a strange anatomical structure. It has a multi-layered structure with eight columns that represent the eight spatial directions, like the eight points of a compass. The relative activation of the cells in the eight columns forms a sinusoid – strongest in one direction, weakest in the opposite direction, and smoothly varying between this peak and trough.

In one layer, the peak corresponds to the direction of the insect’s movement. In another layer, the vertex corresponds to the direction of their goal, such as a food patch or safe nest. The height difference between peak and trough corresponds to the distance to the target. The connections between the layers allow you to shift, add, and subtract these sine wave actions to calculate how to achieve the goal.

Insects use this internal calculator for a variety of tasks. For example, it allows fruit flies to move against the wind, heading towards the origin of the scent haze. Dung beetles can roll the ball in a straight line, away from competitors in the dung pile, while maintaining a specific direction relative to the sun. Monarch butterflies and bagong moths can migrate thousands of miles on the same compass bearing. Honey bees can return to their hives after long foraging trips, keeping track of the direction and distance that will lead them to the food, and can even communicate this information to other bees with a waddling dance.

Inspired by these bugs and insects, engineers are now investigating how we can benefit from this brain circuitry by copying it to solve technical problems such as robot navigation.

For example, GPS isn’t accurate enough for a robot tractor trying to plow a straight line across a rough field, but a beetle’s sun compass can provide the necessary directions. Replicating bees’ homing abilities could provide a backup system for satellite navigation, especially in natural settings.

Another property of schema structure is that competing goals can be balanced or chosen between, flexibly responding to context. This could find application in self-driving cars, enabling quick decision-making in situations where there is no time for long deliberation.

Insect brains use a fraction of the energy of existing computing systems. Interestingly, the central complex circuit is involved in the regulation of sleep in insects, suggesting that efficient energy management may be integral to its function. Thus, learning from nature promises to help solve the energy crisis we all face now.

Professor Barbara Webb FRSE is Professor of Biorobotics in the School of Informatics at the University of Edinburgh and a Fellow of the Royal Society of Edinburgh. This article expresses her own views. The RSE is Scotland’s national academy, bringing together outstanding minds to contribute to Scotland’s social, cultural and economic well-being. Find out more at rse.org.uk and @RoyalSocE