the shift may take the form of an extension of one's sense of self, potentially incorporating the device as an integral part of oneself or expanding the range of sensory and cognitive channels available to the user beyond the traditional senses. Part of the difficulty in determining which changes constitute a threat to identity is rooted in its dynamic nature: since one's personality and concept of self is expected to change with time as a result of emotional development and lived experience, it is not easy to identify clear criteria and draw a line between acceptable shifts and problematic changes. This becomes even harder when dealing with neurotechnologies aimed at influencing psychological processes—such as those designed to recude the symptoms of depression or post-traumatic stress disorder (PTSD) by modulating emotional states or saliency of memories to ease a patient's pain. Even helping a patient remember, which would seemingly help preserve identity, can be a delicate question: "Forgetting is also important to how a person navigates the world, since it allows the opportunity for both losing track of embarrassing or difficult memories, and focusing on future-oriented activity. Efforts to enhance identity through memory preservation thus run the risk of inadvertently damaging a valuable, if less consciously-driven cognitive process." Agency Although the nuances of its definition are debated in philosophy and sociology, agency is commonly understood as the individual's ability to consciously make and communicate a decision or choice. While identity and agency are distinct, an impairment in agency can in turn undermine personal identity: the subject may no longer be able to substantially modify their own self-narrative, and may therefore lose their ability to contribute to the dynamic process of identity formation. The interplay between agency and neurotechnology can have implications for moral responsibility and legal liability. As with identity, devices aimed at treating some psychiatric conditions like depression or anorexia may work by modulating neural function linked with desire or motivation, potentially compromising the user's agency. This can also be the case, paradoxically, for those neurotechnologies designed to restore agency to patients, such as neural prostheses and BCI-mediated assistive technology like wheelchairs or computer accessibility tools. Because these devices often operate by interpreting sensory inputs or the user's neural data in order to estimate the individual's intention and respond according to it, estimation margins can lead to inaccurate or undesired responses that may threaten agency: "If the agent’s intent and