Studying brain fuzz to find effect of seizure therapy

Background noise has been a hot topic for [Bradley] Voytek’s lab in recent years. 

Rather than focusing on orderly brain waves, like alpha waves, that appear at known frequencies, Voytek studies the disorderly fuzz in between. 

Although aperiodic activity generates no obvious pattern on an electroencephalogram, his group has developed statistical tools that reveal its underlying structure. 

It’s this aperiodic structure that the researchers observed in [Maryam] Soltani’s ECT patient data.

In an initial study of nine patients, published in November 2023 in Translational Psychiatry, the researchers reported that aperiodic activity increased after ECT [electroconvulsive therapy]. 

Then, in an accompanying study, the neuroscientists tackled larger data sets previously collected from 22 patients receiving ECT and 23 patients receiving magnetic seizure therapy, which uses magnetic fields rather than electric currents to induce seizures. 

These analyses also found that aperiodic activity tended to increase after the therapies.

Aperiodic activity is thought to relate to the balance of excitation and inhibition in the brain. 

When a neuron receives a signal from another neuron, it will be either excited or inhibited —that is, either more or less likely to fire. In 2017, Voytek and collaborators published a study in the journal NeuroImage suggesting that aperiodic activity reflects inhibitory processes.