Localization of Function, Methods, and Meditation

Localization of Function, Methods, and Meditation

 

I have found myself falling into a routine involving meditation. The most likely time for me to engage in meditation is during the evening after finishing my homework and running my training sessions for my club soccer teams. This simple act which can seem so difficult and uncomfortable in the beginning eventually brings relaxation, peace, and enjoyment; not to mention a much needed break from busy weekly schedules. Meditation increases my concentration and allows me to see situations more clearly. I compare it to an overdue computer reboot needed when a computer begins to slow down from information overload.

Localization of function deals with determining specific regions of the brain associated with the practice; and the increase or decrease of neurochemical activity. Investigations examining transcendental meditation which focuses on mantra repetition, recorded noticeable changes in the anterior cingulated cortex and dorsolateral prefrontal area using electroencephalographic (EEG), functional magnetic resonance imaging (fMRI), and positron emission tomography devices (PET) (Cahn & Polich, 2006). Further examinations showed a direct correlation between increased alpha power and decreased blood flow in the inferior frontal, cingulated, superior temporal and occipital cortices. Zhang, Li, and He (1988) measured results from Qigong meditators who have the ability to deliberately create an inverse correlation between greater alpha power in the frontal cortex, while decreasing alpha power in occipital cortex (Cahn et al., 2006). Decreasing blood flow and alpha power in the occipital lobe suggest less activity in the visual processing area of the brain; thus, decreasing visual stimuli triggering thoughts and emotions. Greater activation of alpha activity is associated with pleasant thoughts or feelings (Brown, B, 1970).

The function that meditation serves is still not fully understood from a science perspective. The purpose of meditation is usually defined by diverse spiritual or religious groups such Yogis and Buddhist. Mindfulness-based practices tend to encourage a nonjudgmental state of continuous thought; whereas concentration techniques focus on bringing attention back to a specific object, mantra, or breathing exercises (Cahn et al., 2006). Researchers suggest that meditation may be a tool to increase focus and attention. Long term meditators showed increases in theta and alpha-1 power; further, oscillations of theta and alpha activity are associated with attention, memory, and cognitive processing (Aftanas & Golocheikine, 2001). Ishihari and Yoshii reported an increase in frontal theta rhythm as a task required more focused attention (Aftanas et al., 2001: Gevins, Smith, McEvoy, & Yu, 1997). These findings suggest that meditative states increase theta power and contribute to stronger memory, focused attention, and positive emotional experience.

A separate experiment performed by Aftanas and Golocheikine (2002) studied the changes in neural activity while participants performed Sahaja Yoga meditation. These types of studies are hard to control scientifically due to the nature of meditation, which is an internal, unobservable change in perception and consciousness. EEG recordings targeted the state referred to as “thoughtless awareness” or “mental silence”. Results showed increased activity of theta waves over the anterior midline regions; similarly, an increase in alpha (increased relaxation) was recorded in the posterior-occipital region. In addition, neurochemical evidence exist that mindfulness based meditation decreased cortisol levels in patients with high cortisol levels initially; and increased cortisol in those with initial low levels (Carlson, Speca, Patel, & Goodey, 2004).

In summary, when psychologists study the cognitive benefits of meditation, they also use many different methods in which they measure the localization of function, and physiological and behavioral effects. Pet scans, MRI’s, and EEG’s are used to collect different forms of data to accurately make observable measurements. These measurements help determine any changes in brain function; and how these changes in brain function contribute to cognitive processes such as attention, memory, and emotions. Despite the evidence that localization of function does exist when it comes to meditation, it is also evident that many regions of the brain are all working together simultaneously.

 

References

Aftanas, I.L., & Golocheikine, A.S. (2001). Human anterior and frontal midline theta and lower alpha reflect emotionally positive state and internalized attention: high-resolution EEG investigation of meditation. Neuroscience Letters, 310(1), 57-60.

Aftanas, I.L., & Golocheikine, A.S. (2002). Non-linear dyamic complexity o f the human EEG during meditation. Neuroscience Letters, 330, 143-146.

Brown, B. (1970). Recognition of aspects of consciousness through association with EEG alpha activity represented by a light signal. Psychophysiology, Vol. 6(4); 442-452.

Cahn, R.B., & Polich, J. (2006). Meditation states and traits: EEG, ERP, and neuroimaging studies. Psychological Bulletin, Vol. 132(2); 180-211.

Carlson, E.L., Speca, M., Patel, D.K., & Goodey, E. (2004). Mindfulness-based stress reduction in relation to quality of life, mood, symptoms of stress and levels of cortisol, dehydroepiandrosterone sulfate (DHEAS) and melatonin in breast and prostate cancer outpatients. Psychoneuroendocrinology, 29(4); 448-474.

Gevins, A., Smith, E.M., McEvoy, L., & Yu, D. (1997). High-resolution EEG mapping of cortical activation related t working memory: effects to task difficulty, type of processing, and practice. Cerebral Cortex, 7(4), 374-385.