This lecture covers the recording of brain activity at focal and network levels, safety monitoring, and state-dependent closed-loop applications. It explores online interference with brain activity, causal understanding, and the challenges of multimodal imaging combined with neuromodulation. The lecture delves into neurosensing, neuromodulation, and the targets and improvements in motor, attention, memory, and decision-making functions. It discusses the use of invasive and non-invasive techniques like EEG, MEG, fMRI, TMS, tES, and TUS. The lecture also examines the effects of brain stimulation on decision-making and memory, as well as the modulation of brain states with prosthetics and robotics.