Electrical activity of the brain

Coenen and Zayachkivska (2013) describe Adolf Beck, who joined the Department of Physiology at the Jagiellonian University in 1889 under Napoleon Cybulski. Following Cybulski's suggestion, Beck began studying the electrical brain activity of animals. Beck recorded negative electrical potentials in several brain areas that were evoked by peripheral sensory impulses.¹ Beck also found continuous electrical oscillations and noted that they ceased after sensory stimulation.² Coenen and Zayachkivska call this the first description of desynchronization in electrical brain potentials.³

Beck sent a short manuscript on localising brain and spinal cord functions by electrical appearances to the Centralblatt für Physiologie, published in 1890. Coenen and Zayachkivska say it became a classic in electrophysiology. In it, Beck located sensory modalities on the cortical surface by electrical and sensory stimulation. The recordings used clay electrodes and a string galvanometer.⁵ The animals were frogs, and paralysed dogs and rabbits. Beck explored which parts of the cortex reacted to stimulation with electronegativity.⁶

According to Coenen and Zayachkivska, Beck's 1890 report set off an intense discussion among physiologists about who could claim to be the founder of electroencephalography. Richard Caton of Liverpool ultimately showed that similar experiments in monkeys had been performed by Caton years earlier.⁴ The held passage is cut off before it says what Beck added, so this article does not report it.

Durant, Lobo, Hammelman and Levin (2016) review planarian regeneration. They describe planaria as having a true centralized brain. They cite Aoki and colleagues (2009) for the statement that this brain produces a continuous brain wave frequency seen by electroencephalogram.⁷ The same passage lists decision-making and lateralization among the animal's complex behaviours. The held text gives no further detail on the recordings.