Renewing the Mind and Neuroplasticity

Paul’s word for transformation (metamorphoō, the same verb the Gospels use for Jesus’ transfiguration in Matthew 17:2 and Mark 9:2) means a real change, not a cosmetic adjustment. Paul places the means of that change in the renewing of the mind. Context matters here. Romans 12:2 follows eleven chapters on God’s mercy and directly follows the call to present our bodies as a “living and holy sacrifice” (12:1). The renewal is a response to grace, carried out by the whole person, body included, and it is aimed at discerning God’s will. The word itself says nothing about brain tissue. But Paul does assume two things that brain research can speak to: that adult minds can really change, and that being “conformed” happens through what we repeatedly take in.

How a brain changes. In 1949 the psychologist Donald Hebb proposed that when one neuron repeatedly helps to fire another, the connection between them strengthens (Hebb, 1949). This is often summarized as “cells that fire together wire together.” Bliss and Lømo (1973) later showed the effect directly in rabbits. Brief, repeated stimulation of a hippocampal pathway made the receiving cells respond more strongly for hours afterward, a phenomenon now called long-term potentiation (LTP). LTP is the best-studied cellular model of learning. A second process works on the brain’s wiring. When a circuit is used heavily, support cells called oligodendrocytes wrap its axons in more myelin, the fatty insulation that speeds and synchronizes signals. In mice, blocking the production of new oligodendrocytes in adulthood stopped animals from mastering a new running-wheel skill (McKenzie et al., 2014). A third piece is chemical. Brain-derived neurotrophic factor (BDNF) is a protein that neurons release when they are active, and it promotes synapse growth and strengthening (Park & Poo, 2013). Taken together, the mechanism is simple to state. Activity that is repeated changes the strength, wiring, and chemistry of the circuits that carry it. The brain becomes better at whatever it does often.

The taxi driver studies. London taxi drivers must learn “the Knowledge”: roughly 25,000 streets and thousands of landmarks. Maguire and colleagues (2000) scanned 16 licensed male drivers and 50 male controls. The drivers had more gray matter in the posterior hippocampus, a region involved in spatial memory. Across drivers, the longer a man had driven, the larger that region tended to be. The study had a less-quoted half: the anterior hippocampus was smaller in drivers, and smaller still in those who had driven longer. A later study compared taxi drivers with London bus drivers, who drive as much and report similar stress but follow fixed routes (Maguire et al., 2006). The hippocampal pattern appeared only in the taxi drivers. The taxi drivers were also worse at learning new complex visual material. Expertise appears to have had a cost elsewhere.

All of these studies were snapshots. They could not rule out that people with unusual hippocampi become taxi drivers. So Woollett and Maguire (2011) followed 79 trainees and 31 controls for three to four years. At the start, the groups did not differ in brain structure, memory, or IQ. Thirty-nine trainees qualified. Only they showed an increase in posterior hippocampal gray matter. Trainees who failed and controls showed no change. Total time spent in training did not separate the groups. The qualifiers had trained about twice as many hours per week. Sustained, concentrated practice, not just exposure to the same environment, went with the change.

A shorter experiment points the same way. Draganski and colleagues (2004) taught about half of 24 young adults (21 women, 3 men) to juggle over three months. Gray matter in visual-motion areas (hMT/V5) and the left posterior intraparietal sulcus increased. Three months after practice stopped, most had lost the skill and the increase had partly receded. A related study of 48 adults (24 trained, 24 untrained) found changes in the microstructure of the underlying white matter after six weeks of juggling practice (Scholz et al., 2009).

Changing how you think changes brain activity. Romans 12:2 is about the mind, not juggling, so the closer parallel is research on changing thought patterns. In cognitive behavioral therapy (CBT), people learn to notice, test, and replace distorted thoughts. Goldapple and colleagues (2004) scanned 14 depressed adults with PET before and after 15 to 20 CBT sessions. Recovery came with decreased activity in parts of the frontal cortex and increased activity in the hippocampus and dorsal cingulate, a pattern different from the one seen with an antidepressant. The study was small, had no untreated control group, and compared with the drug group only after the fact. A later meta-analysis of 22 studies (352 patients) found that the most consistent change after psychotherapy for depression and anxiety was reduced activity in the anterior cingulate, inferior frontal gyrus, and insula, regions tied to emotional reactivity (Marwood et al., 2018). The authors concluded the mechanisms are more complex than a simple “thinking brain calms the feeling brain” story. In the short term, a meta-analysis of 48 imaging studies found that deliberately reinterpreting a situation (cognitive reappraisal) engages control regions in the frontal and parietal lobes and dampens amygdala activity (Buhle et al., 2014).

The limits. These findings deserve care. MRI “gray matter volume” is a statistical signal, not a count of neurons. No one knows exactly which cellular changes produce it in humans. A critical review argued that many training studies have design and statistical weaknesses, and that the most robust human evidence is for exercise-related change in the hippocampus of older adults (Thomas & Baker, 2013). Changes can fade without practice (Draganski et al., 2004), and they come with trade-offs (Maguire et al., 2006). Half the taxi trainees did not qualify, and Woollett and Maguire (2011) note that individual differences, possibly genetic, may limit how much plasticity a given person shows. Plasticity is real, but it is slow, specific to what is practiced, and costly. It is not a promise that anyone can rewire anything quickly.

The convergence. What we repeatedly attend to and practice measurably shapes the organ we think with. The shaping is specific to what we practice, depends on sustained effort, and fades when practice stops. That is not what Paul means by renewal, which is the Spirit’s work in the whole person. But it is consistent with his assumption that minds really can change and with his warning against being conformed. The Greek syschēmatizō suggests being pressed into a mold. The same mechanisms that let Scripture and prayer shape a mind also let the world’s daily inputs shape it. The brain does not distinguish between holy and unholy repetition. It strengthens whatever it is given.

Practice

Living it out

Five practices drawn from this passage. Each says how strong the research behind it is. What the labels mean.

1. 1

   Practice in daily doses, not occasional binges

   The taxi trainees who qualified did not spend more total months training. They spent about twice as many hours each week (Woollett & Maguire, 2011). Choose a fixed daily time with Scripture, even 15 minutes, and protect it the way you would a workout.

   ModerateOne strong longitudinal study, but observational. Trainees chose their own hours, so motivation is a possible confounder.
2. 2

   Memorize Scripture by recalling it, spread out over days

   Rereading a verse feels productive, but trying to recite it from memory produces much better retention after days or weeks (Roediger & Karpicke, 2006). Spreading practice over separate sessions beats cramming (Cepeda et al., 2006). Write a passage on a card, try to say it from memory each morning, check yourself, and review older verses on a widening schedule. That is how “the word of Christ richly dwell[s] within you” (Colossians 3:16) in practical terms.

   StrongThe spacing effect rests on a meta-analysis of 317 experiments. Testing-effect findings are widely replicated, though mostly with students and prose, not Scripture.
3. 3

   Take thoughts captive by naming and reframing them

   When a familiar lie shows up (“I’m a failure,” “God is done with me,” “she always…”), stop, write the thought down, and answer it with what is true from Scripture. This is the core skill of CBT. Over a course of therapy it goes with measurable changes in brain activity (Goldapple et al., 2004; Marwood et al., 2018). In the moment it dampens amygdala reactivity (Buhle et al., 2014). Paul’s “taking every thought captive” (2 Corinthians 10:5) is the same move made in faith.

   ModerateModerate for symptom and brain-activity change in clinical groups. The imaging studies are small and varied. The Christian version has not been tested directly. Anyone with real depression should see a professional, not only a Bible study.
4. 4

   Audit your inputs, because the brain strengthens whatever it is given

   Hebbian learning has no moral filter. Hours of outrage, pornography, or anxious scrolling are rehearsals too. For one week, track where your attention goes. Then cut or replace one input. The juggling study suggests circuits that are not used tend to fade (Draganski et al., 2004).

   See noteThe mechanism is well established in animals. Direct human evidence that cutting a specific media habit changes brain structure is weak.
5. 5

   Present your body, too: move it

   Romans 12:1 comes before 12:2. In a randomized trial with 120 older adults, a year of walking increased anterior hippocampal volume by about 2% and improved spatial memory, while the stretching control group declined (Erickson et al., 2011). The increase tracked higher levels of BDNF. Walk while you pray or review memory verses.

   ModerateModerate to strong. One large RCT, which a skeptical review singled out as the most robust human structural-plasticity finding (Thomas & Baker, 2013). The link to BDNF is correlational, and the sample was older adults.

Studies cited on this page16

1. ↗ Bliss, T. V. P., & Lømo, T. (1973). Long-lasting potentiation of synaptic transmission in the dentate area of the anaesthetized rabbit following stimulation of the perforant path. The Journal of Physiology, 232(2), 331–356. https://doi.org/10.1113/jphysiol.1973.sp010273
2. ↗ Buhle, J. T., Silvers, J. A., Wager, T. D., Lopez, R., Onyemekwu, C., Kober, H., Weber, J., & Ochsner, K. N. (2014). Cognitive reappraisal of emotion: A meta-analysis of human neuroimaging studies. Cerebral Cortex, 24(11), 2981–2990. https://doi.org/10.1093/cercor/bht154
3. ↗ Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354–380. https://doi.org/10.1037/0033-2909.132.3.354
4. ↗ Draganski, B., Gaser, C., Busch, V., Schuierer, G., Bogdahn, U., & May, A. (2004). Neuroplasticity: Changes in grey matter induced by training. Nature, 427(6972), 311–312. https://doi.org/10.1038/427311a
5. ↗ Erickson, K. I., Voss, M. W., Prakash, R. S., Basak, C., Szabo, A., Chaddock, L., Kim, J. S., Heo, S., Alves, H., White, S. M., Wojcicki, T. R., Mailey, E., Vieira, V. J., Martin, S. A., Pence, B. D., Woods, J. A., McAuley, E., & Kramer, A. F. (2011). Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences, 108(7), 3017–3022. https://doi.org/10.1073/pnas.1015950108
6. ↗ Goldapple, K., Segal, Z., Garson, C., Lau, M., Bieling, P., Kennedy, S., & Mayberg, H. (2004). Modulation of cortical-limbic pathways in major depression: Treatment-specific effects of cognitive behavior therapy. Archives of General Psychiatry, 61(1), 34–41. https://doi.org/10.1001/archpsyc.61.1.34
7. ↗ Hebb, D. O. (1949). The organization of behavior: A neuropsychological theory. Wiley.
8. ↗ Maguire, E. A., Gadian, D. G., Johnsrude, I. S., Good, C. D., Ashburner, J., Frackowiak, R. S. J., & Frith, C. D. (2000). Navigation-related structural change in the hippocampi of taxi drivers. Proceedings of the National Academy of Sciences, 97(8), 4398–4403. https://doi.org/10.1073/pnas.070039597
9. ↗ Maguire, E. A., Woollett, K., & Spiers, H. J. (2006). London taxi drivers and bus drivers: A structural MRI and neuropsychological analysis. Hippocampus, 16(12), 1091–1101. https://doi.org/10.1002/hipo.20233
10. ↗ Marwood, L., Wise, T., Perkins, A. M., & Cleare, A. J. (2018). Meta-analyses of the neural mechanisms and predictors of response to psychotherapy in depression and anxiety. Neuroscience & Biobehavioral Reviews, 95, 61–72. https://doi.org/10.1016/j.neubiorev.2018.09.022
11. ↗ McKenzie, I. A., Ohayon, D., Li, H., de Faria, J. P., Emery, B., Tohyama, K., & Richardson, W. D. (2014). Motor skill learning requires active central myelination. Science, 346(6207), 318–322. https://doi.org/10.1126/science.1254960
12. ↗ Park, H., & Poo, M.-m. (2013). Neurotrophin regulation of neural circuit development and function. Nature Reviews Neuroscience, 14(1), 7–23. https://doi.org/10.1038/nrn3379
13. ↗ Roediger, H. L., III, & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249–255. https://doi.org/10.1111/j.1467-9280.2006.01693.x
14. ↗ Scholz, J., Klein, M. C., Behrens, T. E. J., & Johansen-Berg, H. (2009). Training induces changes in white-matter architecture. Nature Neuroscience, 12(11), 1370–1371. https://doi.org/10.1038/nn.2412
15. ↗ Thomas, C., & Baker, C. I. (2013). Teaching an adult brain new tricks: A critical review of evidence for training-dependent structural plasticity in humans. NeuroImage, 73, 225–236. https://doi.org/10.1016/j.neuroimage.2012.03.069
16. ↗ Woollett, K., & Maguire, E. A. (2011). Acquiring “the Knowledge” of London’s layout drives structural brain changes. Current Biology, 21(24), 2109–2114. https://doi.org/10.1016/j.cub.2011.11.018