The document discusses a new technology that can analyze brain activity to determine what a person is seeing or imagining through the use of electroencephalography (EEG) and machine learning algorithms. Researchers were able to decode EEG signals related to different visual categories like faces, scenes and objects and used this to reconstruct images similar to what a person was viewing or imagining with over 50% accuracy. This technology could potentially be used to help communicate for those unable to speak or aid in the design of brain-computer interfaces.