Abstract This review focuses on the role that micro and nanotechnologies are having in the development of a new generation of optical neural interfaces for deep brain regions. The advent of optical methods to control and monitor neural activity has indeed raised neuroscientists’ demand for small, soft and multifunctional devices to interface with sub-cortical structures. These are indeed widely inaccessible with microscopy-based approaches, and the scientific community has proposed complementary methods based on integrated photonics, implantable micro LEDs and engineered optical fibers. After discussing advantages and drawbacks of these methods, the manuscript closes with an overview on the emerging field of optical neural interfaces based on colloidal nanoparticles.