In Surah Ar-Ra'd (13:28), the Quran declares:
"Those who believe and whose hearts find rest in the remembrance of Allah. Verily, in the remembrance of Allah do hearts find rest."
The Arabic term dhikr (ذكر) designates the repeated remembrance and invocation of God, a central practice of Islamic spirituality. The Quran associates this practice with the tranquility of the heart (qalb), a term that, in the Quranic conception, designates both the physical organ and the center of spiritual and emotional perception.
Modern neuroscience has established that the brain possesses a remarkable property: neuroplasticity, its ability to reconfigure itself structurally and functionally in response to repeated experience. Contemplative and meditative practices, which involve mental repetition and sustained attention, induce measurable changes in key brain regions.
Neuroimaging studies have shown that regular meditation practice is associated with increased gray matter density in the prefrontal cortex, hippocampus and anterior cingulate cortex — regions involved in emotional regulation, memory and attention. A landmark study (Hölzel et al., 2011, Psychiatry Research: Neuroimaging) documented these changes after just eight weeks of meditative practice.
Specific research on the Islamic practice of dhikr has shown that the repetition of remembrance formulas induces a decrease in the activity of the default mode network (DMN) — the brain network associated with mind-wandering and rumination — and an increase in activity in regions associated with attention and emotional regulation. Electroencephalography (EEG) studies have also documented an increase in alpha and theta wave coherence during dhikr practice, a state associated with relaxation and stress reduction.
The convergence between the Quranic verse and neuroscience is striking: the Quran, revealed in the 7th century, states that the repeated remembrance of God brings peace to the heart. Modern science confirms that the mental repetition of a calming formula induces neuroplastic changes that reduce the activity of stress circuits and strengthen emotional regulation circuits.
Detractors' arguments
This convergence, although documented, calls for several reservations that should be known in order to preempt criticism:
- Few and recent specific studies: research directly addressing the Islamic practice of dhikr is still scarce, often small-scale and recent. Most of the robust data comes from studies on mindfulness meditation, not specifically on dhikr.
- Non-specific effect: the observed neuroplastic changes are not unique to dhikr, but common to any contemplative or soothing mental-repetition practice (prayer, meditation, relaxation). They therefore do not demonstrate a particularity of dhikr as such.
- Contested scientific interpretation: the verse speaks of the tranquility of the "heart" (qalb) in a spiritual and metaphysical sense. Equating it with neurobiological mechanisms reflects a scientific reading of the text that many exegetes and scholars consider anachronistic.
- Risk of reduction: reducing the tranquility promised by the verse to a mere neurobiological effect could obscure the spiritual and relational dimension with God, which is the primary meaning of the text.