This paper describes a variety of motor release phenomena, including manual grasping and groping, imitation behavior, utilization behavior, and alien hand sign, their clinical manifestations. and proposed neural mechanisms. One of these specific neurobehavioral disorders, initially described by Lhermitte (Brain  106: 237-255), and termed utilization behavior, is addressed in more detail. Patients with this disorder are described as reaching out and using objects in the environment in an automatic manner. The current paper provides a comprehensive review of studies that have documented utilization behavior in individuals with a variety of pathologies, all having a specific predilection for the frontal lobes and frontal-striatal systems. Goldberg's (Behavioral and Brain Sciences  8: 567-616) theoretical framework for understanding motor release phenomena, which conceptualizes these behaviors as resulting from an imbalance between proposed medial (voluntary, goal directed, and future directed) and lateral (automatic, stimulus bound, and visually based) motor systems, is also discussed. Utilization behavior may prove to be a common underlying cause of high levels of excessive and intrusive motor behaviors within various clinical populations. A more comprehensive understanding of the neural systems underlying utilization behavior may prove highly useful for the differential diagnosis of conditions involving the mesial frontal cortex and fronto-striatal connections. Recent studies have started to investigate utilization behavior in clinical populations with known or suspected frontal system dysfunction, including adult patients with a variety of psychiatric conditions and children with ADHD.