Unlike other body parts, the brain has no sensory receptors. Consequently, there is no direct mechanism to sense its operations. This can only be done through conscious attention to the workings of the mind. Meditation allows one to hone the skills needed to consciously focus attention onto the workings of the brain. By quietening the mind and reducing the interference from spurious activity, one can begin to sense the operations of the brain.

The nucleus accumbens is an area that lies deep within the brain. It may be thought of as the brain's pleasure center because more than any other region of the brain, activity in this region corresponds to the experience of pleasure and liking. When receiving a reward of some kind the nucleus accumbens is active. Similarly, it is active during pleasurable experiences, such as listening to enjoyable music , or even thinking about pleasurable experiences.
I have been exploring meditation techniques that target the nucleus accumbens as a means to trigger pleasant sensations. My experience has been that one must first reach a state of very deep relaxation in which the brain is quiet and there are few intrusive thoughts. The goal is to recognize pleasant sensations within the brain and learn to generate patterns of brain activity that produce these sensations. It should be noted that this does not involve recalling pleasant memories as this has the potential to generate patterns of brain activity that interfere with one's awareness of their brain. I have used a technique in which I imagine the brain is an empty vessel and deep within that empty vessel is the nucleus accumbens. Then, I imagine poking it and with each poke, waves of pleasant sensations emanate from the nucleus acumbens and spread throughout the rest of the brain.
References regarding nucleus accumbens
- Knutson, B., et al. (2001). Anticipation of Increasing Monetary Reward Selectively Recruits
Nucleus Accumbens. J of Neuroscience
- Sabatinelli, D., et al. (2007). Pleasure Rather Than Salience Activates Human Nucleus Accumbens and Medial Prefrontal Cortex. J of Neurophysiology
- Salimpoor, V.N., et al. (2013). Interactions Between the Nucleus Accumbens and Auditory Cortices Predict Music Reward Value. Science