Neurotechnology is any tool that directly, exogenously observes or manipulates the state of biological nervous systems, especially the human brain.

Familiar examples include electrode-based brain-computer interfaces (BCIs), antidepressant drugs, or magnetic resonance imaging (MRI). It has been argued that BCIs specifically could make robust totalitarianism significantly more likely, and that such devices should for that reason be regarded as an existential risk factor.^[1]