Neuroscience and Psychology of Meditation in Everyday Life

by Dusana Dorjee

  The increasing levels of proficiency in long-term practice of the visualization-based deity meditation are not only associated with the usual signs of progression in Shamatha practice – increased clarity and stability of meditation – they are also accompanied by phenomenological shifts in terms of connection with the qualities of the deity. These can, for example, manifest as an experience of gradients in the progression of compassion training, from basic levels to the non-referential experience of compassion. At the same time, the practitioner may notice gradual shifts in her existential awareness – experiential deepening of the realization of emptiness (construed nature) of self as well as the illusory nature of reality. This demonstrates how visualization-based practice can work at the attention, emotion and insight levels at the same time. Yet, there is also a sense of the sequential nature of the progression at these three levels where increased levels of stability and clarity enable enhancements in development of emotion qualities such as compassion and these then together serve as catalysts for existential insight and progression in MEA.

  After sustaining the deity visualization for a certain amount of time, the practitioner gradually dissolves the visualizations in the opposite order to the one applied at the beginning of the practice when the visualization was created. This process of dissolution is symbolic of purifying the experience of death (Kongtrul, 2002). The dissolution of the seed syllable of the deity is typically the last step in the visualization followed by abiding in the awareness of awareness, emptiness of self or pristine awareness based on the capacity and proficiency of the practitioner. This again serves as a reminder of the illusory nature of the visualization, which is construed, yet in comparison to our usual perceptions of reality pure in its nature. Some teachers recommend these non-conceptual phases of the visualization-based practice to be equally long as the time spent in creating, maintaining and dissolving the visualization.

  After the silent non-conceptual phase practitioners often visualize themselves as the deity and visualize others and surroundings as deities and the pure land just like in meditation. This visualization is sustained in breaks between formal meditation sessions. The purpose of this visualization is to remind ourselves repeatedly, throughout the day, of the essential pure nature of our mind and our experiences even though it can be superficially morphed into various construed forms and afflictions. At the end of the formal visualization-based meditation session we remind ourselves of the wholesome states cultivated during the practice and dedicate the merit with a wish that the practice would support us in progressing on our path towards existential well-being so that we can be free from suffering and help others achieve the same.

  Neuroscience of visualization-based meditation

  Activation of brain areas during visualization seems to closely resemble the activation of the brain during actual perception of the visualized object (Kosslyn, Ganis and Thompson, 2001). So, for example, when we are looking at a picture of the deity or visualizing it, the brain parts activated during both processes are very similar. There are, however, slight differences in the robustness of the overlap between different brain areas involved in visual perception and imagery. These areas include a hierarchy of brain regions progressing from early visual areas such as V1 of the occipital cortex to highest levels of visual processing in the ventral temporal lobe (Pearson et al., 2015). This progression of visual areas is referred to as a hierarchy because the early visual areas specialize in low-level processing of features such as edges or location of shapes on the retina whereas high-level visual processing involves more abstract representations, for example of what objects as wholes look like. So the hierarchy follows a trajectory of increasing abstractness and meaningfulness of the visual representations.

  Interestingly, research studies have reported strong overlap in activation of higher level visual areas in both perception and visual imagery, whereas the brain activations in early visual areas seem to follow the same patterns but differ in intensity with imagery producing weaker patterns. This could be due to closer proximity and more neural connections between higher level visual areas and regions of the medial temporal lobe which encode memories including remembered images. However, greater clarity and vividness of imagery has been linked to activation in early visual areas V1 and V2 (Cui et al., 2007). Importantly, these lower visual areas not only send but also receive information from higher visual areas which can inform the clarity of visualization.

  This understanding of the processes involved in visual imagery seems to support the progression of long-term meditation training in the visualization-based practices that starts with low clarity of detail in the visualization and reliance on more abstract representations of what is being visualized. With repeated practice, the practitioner is able to visualize the deity image in increasingly more detail which might be supported by increasing involvement of early visual areas in creating the visualization supported by feedback loops from higher level visual representations of the visualized image. Based on this theory, it would be expected that the most advanced levels of proficiency in visualization-based meditation practices would be associated with patterns of activation in both high- and low-level visual areas which would be very similar to activations in response to viewing the visualized image. No research has so far evaluated this prediction.

  Brain activation during mental imagery also closely overlaps with brain activation associated with visual working memory (Pearson et al., 2015). Indeed, studies have shown that whether research participants are instructed to hold an image in their memory or to create a mental image, both instructions lead to very similar activation in the V1 early visual area of the brain. This is perhaps not surprising given that most of us would use mental imagery as a tool in trying to remember an image, even though there are individual differences and some people may prefer using verbal descriptions to encode visual images in their memory. This highlights differences in individual propensities towards mental imagery with those who have clear preference for imagery memory encoding being perhaps more inclined to also engage in visualization-based meditation practices.

  Given the overlap between mental imagery and visual working memory it might also be expected that extensive experience in visualization-based meditation practice would be associated with better performance in mental imagery tasks. Such performance enhancements could be either due to improvements in imagery processing or greater visual working memory capacity. An earlier case study with only one experienced meditator suggested that deity visualization is associated with enhanced right posterior gamma activity in the brain (Lehmann et al., 2001). In this study the meditator has been asked to engage in several different types of meditation including Buddha visualization, mantra recitation and dissolution of self. The gamma activity at 40 Hz frequency across the brain was measured during the meditation practices and the sources of the gamma activity were derived in further post-hoc analyses. The gamma activity was the target of the investigations because other researchers suggested that it is an index of conscious activity and, in case of visual processing, also of binding visual features into a meaningful representation of an object or scene. The findings of the study showed differential localization of gamma activity across the different meditation practice styles. The results in the visualization meditation suggested distinct activation in the right posterior areas which in comparison to mantra recitation was localized to the right middle temporal lobe. In line with the research evidence outside of meditation research the results of this study indicated that deity practice, just like other imagery tasks, results in activation of high-level visual processing areas.

  The previous study provided interesting initial results, but also had limitations in terms of examining the effects of one participant rather than a group and measuring brain activity during meditation only. This does not allow for inferences about possible trait effects outside of meditation practice resulting from long-term visualization-based meditation training. These shortcomings were addressed
in another study which investigated the performance of meditators in computerized mental imagery and visuospatial working memory tasks before and after deity meditation practice. The participants in the study were meditators experienced in deity practices, meditators with experience in other types of meditation (open presence) and meditation novices (Kozhevnikov et al., 2009). Specifically, the performance of participants in the groups was compared before and after the meditators engaged in 20 minutes of deity practice (first meditator group) or 20 minutes of open presence practice (second meditator group) and controls engaged in other imagery tasks for the same amount of time.

  No differences in performance across the groups were found at the baseline, before the groups engaged in meditation practice. This is somewhat surprising because it could be expected that regular visualization-based practice would result in trait-like improvements in mental imagery or visual working memory capacity, which would be present within and outside of formal meditation. However, large differences between the meditators skilled in deity practice and the other groups were observed after the meditation practice. The meditators in the deity practice group showed large and significant enhancement in their performance on both the mental imagery task involving spatial rotation and the visuospatial working memory task. These findings were interpreted in terms of deity meditation resulting in temporary enhancements in the access to visuospatial processing resources. Such interpretation would perhaps be consistent with more efficient use of a greater capacity of visuospatial working memory. Given the absence of this effect before the deity meditation, it seems that the improved performance depends on state-induced enhancement, but this state shift is likely enabled by trait-like changes in the ability to recruit the resources in meditation since similar effects were not observed in the other groups of meditators or meditation novices.

  The findings of increases in mental imagery and visuospatial working memory after deity meditation were replicated in another study with the same computerized tasks which compared the performance of experienced Theravada practitioners and Tibetan Buddhist practitioners (Amihai and Kozhevnikov, 2014). The practitioners of the Theravada tradition who did not train in deity practices did not show significant improvements in their performance after 20 minutes of either calm abiding or Vipassana practice. In contrast, the Tibetan Buddhist meditators showed improved performance on the two tasks after deity practice. In addition, the study assessed possible differences in heart-rate variability as an indicator of sympathetic and parasympathetic activity in the two groups of meditators. The findings revealed significant increases in para-sympathetic activity in comparison to rest in the Theravada meditators and significant increases in sympathetic activity in comparison to rest in the Tibetan Buddhist meditators. These results were interpreted in terms of increased arousal in the Tibetan Buddhist meditator group possibly contributing to their enhanced performance on the mental imagery and visuospatial tasks.

  Overall, the limited research evidence on the effects of visualization-based meditation suggests that this type of practice is associated with distinct patterns of brain activation in higher level visual areas of the brain which would be expected during any mental imagery task. More importantly, deity meditation has also been shown to significantly enhance performance in experienced meditators on mental imagery and visuospatial working memory tasks right after completion of the practice. No studies have so far assessed the progression of changes in the brain with increasing proficiency in visualization-based meditation. It could be expected that changes in the higher visual areas of the brain gradually propagate to lower visual areas as clarity of detail in the practice increases. Finally, no studies so far investigated the possible impact of these practices on the development of compassion or other wholesome emotional qualities and the cultivation of insight into the nature of self and reality.

  Visualization-based meditation, self-regulation and well-being

  As we have discussed earlier, visualization-based meditation seems to primarily impact attention and meta-awareness, but can also support development of emotional qualities and insight. Such changes are likely to have broad impact on the development of our self-regulation skills. Specifically, visualization-based practices aim to enhance the stability and clarity of attention with practitioners gradually able to sustain focus on the meditation for longer and with more attention to details of the visualized image. Just like other meditations training attention, the practitioner at the same time monitors distractions and redirects attention back to the visualized image – practice which aims to enhance meta-awareness and attention control as core aspects of the metacognitive self-regulatory capacity (MSRC) (Dorjee, 2016).

  However, visualization-based meditation also aims to develop compassion, loving kindness, rejoicing and equanimity – qualities which are represented by the visualized images of deities. Many of these visualizations involve imagining the deity sending out light of compassion to all sentient beings which provides comfort and purifies afflictions as the root causes of their suffering. The practitioner also visualizes her own afflictions to be transformed or purified through such practice. In this way, visualization-based meditations on the deity explicitly cultivate wholesome emotional qualities. Hence, training in these types of meditation would also be expected to improve the emotional well-being and the emotion regulation skills of practitioners, which are the second dimension of the MSRC.

  Visualization-based practices likely also significantly impact the conceptual systems which contribute to the MSRC. This is because this type of meditation involves visual imagery and thus reduces the engagement in ruminative verbal modes of thinking and speaking. The visualizations may also prompt the development of new cognitive schemas which with repetition may replace habitual schemas of the ordinary afflictive reality. In addition, visualization-based practices are typically also accompanied by recitation of mantras. This most likely further reduces the engagement in ruminative thought given that both visual perceptual channels and verbal channels are highly active during such meditation, leaving very limited mental resources of working memory for ruminative thinking.

  Depending on the proficiency and depth of engagement with the visualization-based meditation, these practices can also support practitioners in the development of increasingly advanced MEA. For example, deity meditations emphasize the illusory nature of ordinary afflictive reality and the visualizations represent also illusory, but pure, representations of reality. In addition, with advancement in deity practice, the practitioner may start focusing more closely on the wisdom (insight) aspects of the deity and try to identify with their representations of the nature of mind and reality. In this way, the deity meditations may loosen up the conditioned notions of self and enable the practitioner to experientially understand its construed nature. At the most advanced levels, the deity practice can be a catalyst for practitioners’ recognition of pristine awareness represented by the mind of the deity and from which the deity visualizations ultimately arise and dissolve to. Thus deity practice can provide multifaceted support for long-term practitioners of meditation who can connect with different aspects of the practices depending on their stage of progression on the path towards existential balance.

  A day of visualization-based meditation

  Whilst most of the previous discussion focused on the deity meditation in the Tibetan Buddhist context, visualization-based practices can enrich long-term meditation practice of meditators across contemplative traditions as well as religious and non-religious contexts. We will thus consider how these types of meditation can be introduced into everyday routines both as Buddhist practices and secular techniques. Starting early in the morning right after waking up, a Tibetan Buddhist practitioner would typically visualize the lineage of Buddhas and the accomplished master she has been following and in this way connect with their accomplishments and teachings as a way of motivating her engagement in meditation practice throughout the day. A secular practitioner could perhaps use visualizat
ion-based practice at the beginning of the day to imagine how they will go through the day by engaging in the daily activities mindfully, with meta-awareness and with qualities of compassion and loving kindness. Visualizations would also be used during morning routines when practicing Tonglen (giving and taking) such as imagining all sentient beings having a wholesome meal or not experiencing the difficulties we are experiencing.

  While commuting, a Tibetan Buddhist meditator can practice the deity meditation by visualizing others as deities, which can serve as a reminder of the pure nature of mind that is present all the time in all sentient beings despite the lack of their connection with this aspect of their consciousness. The practice would also serve as a reminder of the illusory nature of the conventional reality and changeable nature of mental afflictions. This practice can be further enhanced by remembering the unconditional compassion qualities of the deity and trying to apply these when engaging with others throughout the day. A meditator practicing in the secular context could use visualization practices to enhance their meditation on compassion, loving kindness, rejoicing and equanimity by imagining themselves in a state of unconditional compassion and visualizing others experiencing the same state.