The anterior limb of the internal capsule: Anatomy, function, and dysfunction

•The ALIC has been implicated in the pathophysiology of numerous mental illnesses.•The ALIC includes thalamocortical fibres that form important psychiatric circuits.•Neuroimaging studies demonstrate consistent ALIC changes in specific mental illnesses.•The functional anatomy of the ALIC makes it a salient target for psychiatric neurosurgery. The last two decades have seen a re-emergence of neurosurgery for severe, refractory psychiatric diseases, largely due to the advent of more precise and safe operative techniques. Nevertheless, the optimal targets for these surgeries remain a matter of debate, and are often grandfathered from experiences in the late 20th century. To better explore the rationale for one target in particular – the anterior limb of the internal capsule (ALIC) – we comprehensively reviewed all available literature on its role in the pathophysiology and treatment of mental illness. We first provide an overview of its functional anatomy, followed by a discussion on its role in several prevalent psychiatric diseases. Given its structural integration into the limbic system and involvement in a number of cognitive and emotional processes, the ALIC is a robust target for surgical treatment of refractory psychiatric diseases. The advent of novel neuroimaging techniques, coupled with image-guided therapeutics and neuromodulatory treatments, will continue to enable study on the ALIC in mental illness.