Focused attention meditation
In FA meditation practice, high attentional stability and vividness (acuity) are achieved in a mental state of concentrated calm or serene attention, denoted by the word samatha (with the literal meaning of quiescence) in the Buddhist contemplative tradition (Wallace 1999). By using a telescope analogy, Wallace
(1999) observed that in FA or samatha meditation, the development of atten- tional stability may be likened to mounting a telescope on a firm platform, while the development of attentional vividness is like polishing the lenses and bringing the telescope into clear focus.
Apart from sustaining attentional focus on an intended object, FA meditation also involves the regulative skills of monitoring the focus of attention, detecting distraction, disengaging attention from the source of distraction, and refocusing on the object (Lutz et al. 2008a). FA meditation techniques involve observing the experiential field by allowing thoughts and sensations to arise and pass without clinging to them, and maintaining attention on an object or bringing it back to the specific object of focused attention, in order to develop an internal “witnessing observer” (Cahn and Polich 2006). The attentional and monitoring functions of FA meditation have been related to different systems in the brain involved in attentional control and in selective and sustained attention (Lutz et al. 2008a; see also Weissman et al. 2006). The neural correlates of such different FA meditation functions have recently been described by a functional magnetic resonance imaging (fMRI) study conducted by Hasenkamp et al. (2012). This study elegantly identified different brain regions involved in mind wandering (distraction), awareness of distraction, shifting back to the meditation object, and then sustaining focus on it.
Srinivasan and Baijal (2007) reported changes in automatic sensory processing at early stages (before the intervention of attention) due to concentration (FA) meditation. Frequent and infrequent auditory tones were presented to meditators before meditation and while exiting meditation, and to a control group who practiced relaxation. The results showed increases in brain waves (“mismatch negativity” amplitudes) immediately after and before meditation, indicating enhanced sensitivity of the perceptual system of the meditators at early sensory processing stages, even before attention could be allocated for a cognitive task. Changes in perceptual processes have also been shown in a study of expert meditators (Tibetan Buddhist monks) who could sustain a perceptual state (motion-induced blindness) for a significantly longer period in an FA meditation state (Carter et al. 2005). The study also reported longer durations with a binocular rivalry task, in which conflicting inputs are presented to the two eyes (with uncontrolled switches between the two in perceptual awareness in general participants), indicating possible changes in the brain mechanisms responsible for perceptual awareness, as a state effect of FA meditation based on (trait) meditation expertise (Carter et al. 2005).
In addition to enhancement of perceptual processing, meditation practice is associated with changes in attentional processes dependent on the nature of the meditation practice (Baijal et al. 2011). A study with children who practiced transcendental meditation showed that not all attentional processes benefited from increased practice and expertise (Baijal et al. 2011). More specifically, they investigated alerting (the ability to enhance attention by an external trigger), orienting (the ability to direct attention to a cued location), and conflict monitoring (the ability to prevent interference from a distracter flanker) using the Attention Network Test (ANT). While conflict monitoring and alerting performance was different between meditators and controls, there was no difference in orienting. The results also showed that those practicing transcendental meditation were better able to handle conflict trials that were followed by nonconflict trials, indicating a benefit in reactive control mechanisms.
An fMRI study with practitioners of FA meditation showed lower activation in regions related to distraction and task-unrelated thoughts compared to controls during a task that required the observers to ignore auditory stimuli (Brefczynski-Lewis et al. 2007). Practice of FA meditation appeared to result in enhanced ability to focus attention, thereby reducing the effects of irrelevant stimuli. During FA meditation compared to rest, there was activation in multiple regions associated with monitoring and engagement of attention (such as dorsolateral prefrontal cortex, visual cortex, and superior frontal and intraparietal sulci). Interestingly, the strength of activity in these regions showed an inverted м-shaped curve with meditation. Meditators with moderate experience showed stronger activation but very experienced meditators showed less activation. The м-shaped pattern of brain activity suggests that, with very extensive mental training such as the practice of FA meditation, minimal effort might be necessary to sustain the focus of attention.
We will now focus on OM meditation, which unlike FA meditation does not involve focusing on a specific meditation object, such as breath sensations linked to an area of the body. OM meditation just involves a receptive awareness of the fields of experience in the present moment, without an explicit focus or sustaining attention onto any perceptual, feeling, or thought content.