Definition of opacity for English Language Learners. : 1  the quality of a material that does not allow light to pass through it : the quality of being opaque. : 2  the quality of being difficult to understand or explain.
Research has shown that this is not true, and that brain cells can and do regenerate, especially in the areas related to learning, decision-making, visual recognition, and the way people perceive objects in space.weet. For a long time, scientists thought that it was impossible for brain cells to regenerate because they assumed that any new cells would disrupt the order of the brain.
However, the best therapy should be able to also repair damage. The spinal cord (and the brain) is well known for its inability to self-heal. However, the right environment can induce axons of the spinal cord to regenerate. But it is precisely in this environment that lies the main problem, since the spinal cord contains a myriad of molecules that actively inhibit axonal regeneration.