Systems and methods associated with brain computer interfaces (BCIs) are disclosed. Embodiments herein include features related to one or more of optical-based brain signal acquisition and/or processing, decoding/encoding modalities, brain-computer interfacing, AR/VR content interaction, and/or electronic wave (E-wave) detection, determination and/or processing, among other features. Certain example implementations may include or involve aspects or processes such as monitoring the gaze and brain activity of a user (e.g., via a BCI, etc.) interacting with a user interface (UI), detecting that the gaze of the user is directed at an element of the UI, detecting or processing an E-wave in temporal conjunction with the gaze at the element, determining that the users intends to interact with the element, and/or triggering an interaction with the element. Further, aspects of present systems and methods may be configured to leverage BCIs and/or non-invasive wearable device features to provide enhanced user interactions for various devices.