Chronicle: "In June 2025, Nataliya Kosmyna and colleagues at the MIT Media Lab released a preprint titled 'Your Brain on ChatGPT.; They divided 54 participants into three groups writing SAT-style essays — one using ChatGPT, the second group using a search engine, the last group using nothing — and monitored brain activity with a 32-channel EEG. The ChatGPT group showed the lowest neural connectivity of the three, with up to 55 percent reduced connectivity compared with the brain-only group, and 'consistently underperformed at neural, linguistic, and behavioral levels.' [...] When the LLM group was forced to write without AI in a follow-up session, their brain activity did not bounce back to baseline; the researchers coined the term 'cognitive debt' for the lingering deficit.