A horse’s brain waves can reflect their welfare state according to recent research.
Electrical activity in the brain varies with the state of arousal of the different parts of the brain and the electrical waves have been grouped into bands according to their frequency: eg delta (δ: 0−4 Hz), theta (θ: 4−8 Hz), alpha (α: 8–12 Hz), beta (β: 12–30 Hz) and gamma (γ: >30 Hz).
Theta waves tend to predominate during calm and relaxed states, while an alert state tends to produce more gamma waves.
Mathilde Stomp and colleagues at the University of Rennes, France, devised a headband for horses, to record the resting electrical activity in the brain (EEG – electroencephalogram). Then, to see if there was an association with the horses’ welfare state, they compared the patterns of electrical activity with an assessment of the horses’ behaviour.
Eighteen horses involved in the study were maintained under either “restricted” conditions (living in riding school stables with a few hours daily turnout on pasture and regular work) and “leisure” (on pasture all year round, with occasional leisure riding.)
The researchers found that theta waves tended to predominate in both sides of the brain in horses in a more positive welfare state, whereas beta waves tended to predominate in horses showing signs of compromised welfare. Horses in a good welfare state produced fewer gamma waves in the right side of the brain.
A full report of the work is published in Applied Animal Behaviour Science. The authors suggest that “bilateral and left hemisphere theta activity is a promising neurophysiological marker of good welfare in horses, while a bilateral or RH [right hemisphere] high production of gamma waves should alert about potential welfare alterations.”
For more details, see:
Brain activity reflects (chronic) welfare state: Evidence from individual electroencephalography profiles in an animal model.
M. Stomp, S. d’Ingeo, S. Henry, H. Cousillas, M. Hausberger.
Applied Animal Behaviour Science, (2021) vol 236, 105271.