Open monitoring meditation
Lutz et al. (2008a) suggest that OM meditation can strengthen regulatory influences on emotional processes, through prefrontal regulation of limbic responses. Indeed, neuroimaging studies have shown that simple verbal labeling of affective stimuli leads to the activation of the (right) ventrolateral prefrontal cortex, and to reduced responses of the amygdala through ventromedial prefrontal cortex activity (Hariri et al. 2000; Lieberman et al. 2007). This strategy of labeling aspects of experience (e.g., “this is unpleasant”) is used in vipas- sana (or insight) meditation, for example, and nurtures a more detached awareness of affective content in moment-to-moment experience.
In OM meditation, monitoring is reflected in the capacity to notice arising sensory, feeling, and thought events in the present moment within an unrestricted receptive awareness. In the transition from an FA to an OM meditative state, which may for example take place after some minutes in a meditation sitting, the object as the primary focus is gradually replaced by a sustaining of an open awareness (Lutz et al. 2008a). Behavioral studies of OM meditators have shown a more distributed attentional focus (Valentine and Sweet 1999), enhanced conflict monitoring (Tang et al. 2007), and reduced attentional blink or more efficient resource allocation to serially-presented targets (Slagter et al. 2007).
Lutz et al. (2004) found a high-amplitude pattern of synchrony in the gamma oscillatory band in expert meditators during an emotional version of OM meditation (non-referential compassion or loving kindness meditation). In that study, compared with a group of novices, the practitioners (with a mental training of 10,000 to 50,000 hours over time periods ranging from 15 to 40 years) self-induced higher-amplitude sustained gamma band oscillations and long- range phase synchrony, especially over lateral frontoparietal electrodes, during meditation. This pattern of gamma band oscillations and synchrony was also significantly more pronounced in the baseline state of the long-term practitioners compared with the novices, thus suggesting a neuroplasticity-based transformation in the default brain mode of the practitioners.
Therefore, mental training based on both FA and OM meditation leads to changes of brain activity that can be observed both as trait-related (off the cushion) and as related to meditation states (during or immediately after meditation), though with remarkable differences in brain activity patterns for FA and OM meditation. We will now focus on the possible complementarity of FA and OM meditation within a unitary meditation practice, i.e. by regarding FA and OM facets of meditation as two aspects that can be expressed in alternation within the same meditation sitting.