New research on brain plasticity will blow your mind. One amazing finding is that new stem cells are produced in the lateral ventricals of the adult brain (1). What is even more amazing is how these stem cells migrate from the back of the brain to the olfactory bulb in the front of the brain (2). Using time lapse imaging scientists have been able to watch stem cells latch onto a blood vessel highway and drag themselves to their destination. First, brain chemicals push stem cells away from their birth place. Additional chemicals stop the stem cells from getting off track along the way. As the cells approach their destination more chemicals pull them in the right direction.
Equally amazing is the fact that new stem cells are produced in the hippocampus that controls memory (2). Since learning is life-long, it is hard to believe that neuroscientists used to believe that remembering everything we learn can be crammed into the memory cells we were born with. The adult brain grows thousands of new stem cells in the hippocampus every day (3). Diffusion tensor imaging allowed scientists to see significant microstructure changes in the hippocampus after two hours of training (4).
New technology confirms that nerve cells can sprout new branches. For example, Marshall describes cortical regeneration associated with finger-thumb opposition (5). A youtube video shows a neurite advancing towards other nerve cells and retreating. New growth is called a neurite until it differentiates into an axon or a dentrite (6). Researchers are still learning which chemicals support or hinder the neurogenesis seen in the video. But they know that only repeated training makes new branches cluster together so they work efficiently as a group (7). I haven't seen research that says how much repetition is needed to produce neuroplasticity. I'm pretty sure a few minutes of exercise each day followed by hours of disuse isn't enough.
I want to pull my hair out every time I hear someone say "The doctor told me there is a 6 month window for recovery after a stroke." I wish doctors would refer their clients to health care professionals who keep up with the latest brain research and advances in stroke rehab.
1. Carreira, B., Carvalho, C., & Araujo, I. (2012). Regulation of injury-induced neurogenesis by nitric oxide. Stem Cell International, article ID 895659, 15 pages.
2. Bozoyan, L., Khlghatyan, J., & Saghatelyan, A. (2012). Astrocytes control the development of the migration-promoting vascular scaffold in the postnatal brain via VEGF signaling, J. Neurosci, 32, 1687-1704.
4. Sagi, Y., Tavor, I., Hofstetter, S, Tzur-Moryosef, S., Blumenfield-Katzir, T., & Assaf, Y. (2012). Learning in the fast lane: New insights into neuroplasticity, Neuron, 73,(6), 1195-1203.
5. Marshall, R., Perera, G., Krakauer, J., Constantine, R., & DeLaPaz, R. (2000). Evolution of cortical activation during recovery from corticospinal tract infartion. Stroke, 31, 656-661.
6. Khodosevich, K, & Monyer, H. (2010). Signaling involved in neurite outgrowth of postnattally born subventricular zone neurons in vitro., BMC Neuroscience, 11(18), 11-18.
7. Jabr, F. (2012). Spine tuning: Finding physical evidence of how practice rewires the brain, Scientific American, April 16, 2 pages.