Shundo David Haye – Zen Priest

‘To identify the neural correlates of these different modes of thinking, Christoff Hadjiilieva puts people in functional magnetic resonance imaging (fMRI) scanners and asks them to press one button when it feels like their thoughts are moving freely and another button when it feels like their thoughts are somehow constrained. She has come to see the conscious mind as seesawing between constrained and unconstrained thinking. In brain scans, this phenomenology shows up as a contest between the executive control network at the front of the cortex and the default mode network further back in the brain.

In an attempt to pin down the unconscious origins of our conscious thoughts, Christoff Hadjiilieva conducted an experiment with long- term meditators (mindfulness practitioners). These are people who have been trained to still their minds but also to notice the precise moment when that stillness is broken by an errant thought, which Christoff Hadjiilieva found happens every 10 to 20 seconds or so even in these trained minds. (“The big lesson of meditation,” she said, “is that the mind cannot be controlled.”)

Volunteers were instructed to meditate while inside the tube of an fMRI machine and press a button whenever a thought arose. Christoff Hadjiilieva and her colleagues noted a jump in activity within the hippocampus, a key component of the default mode network that is involved in not only memory but also learning and spatial navigation. They might have predicted this location but not the timing. To their surprise, the leap in hippocampal activity preceded the arrival of the thought in the meditator’s consciousness by nearly four seconds – an epoch in brain time, and far longer than it takes for a sensory impression to cross the threshold of our awareness.

“Something is going on prior to awareness,” Christoff Hadjiilieva said, but she’s not sure exactly what it is or why it takes so long. This finding indicates that a spontaneous thought must undergo some sort of complicated unconscious processing before finding (or forcing) its way into the stream of consciousness.’ (from the Guardian)