One of the central problems in systems and computational neuroscience is how the central nervous creates and updates internal representation of limb dynamics to manage complex, programmed movements under changing environmental conditions.

The solutions should explain a wide variety of human behaviors, as well as forming the basis for treatments of diseases such as strokes, spinal chord injuries, and various motor learning disorders.

Recent studies have provided insight into how internal representations are built in the central nervous system and how motor memories are altered during learning. Evidence suggests that internal representations form by combining modular primitives in the spinal cord as well as other building blocks in higher brain structures. Experimental studies on spinalized frogs, rats, and cats have shown that the premotor circuitry within the spinal cord is organized into a set of discrete modules. When each module is activated, a specific force field is evoked. Simultaneous activation of multiple modules results in a vectorial combination of the fields.

Other studies have shown that motor memories change over time by consolidating memories of learned movements, each of which initially exists in a vulnerable state. Surprisingly, neural circuitry for memories in the cortical frontal motor areas differs markedly from neural memory circuits responsible for facts and events.

The McGovern Institute is sponsoring research to explore these areas in detail, combining animal studies involving brain imaging of behavior, computer modeling of neural architecture, and focused stimulation of neurons in selected regions of the central nervous system.