Recent understanding of our nervous system reveals that sensory organs are optimized for efficient uptake of information from the environment to the brain. While bulk of the energy consumed in this process is to generate asynchronous action potentials for signal communication, evolutionary pressure has further optimized on this mode of communication within the brain for efficient representation and processing of information. We will explore this link between energy and information to reveal some of the mechanisms, circuits and energy efficient codes in the brain. The implications of this link will be important to consider for the design of neuromorphic systems of the future.