the brain is an unknown, there are estimations ranging from 100 billion to an approximate 128 billion. This allows a vast neural network to be formed, and consequently a "storage capacity of the human brain." Competition between neurons plays a key role in establishing the exact pattern of connections. Through neuron-neuron communication made possible by the neuron's synapses, axon, and dendrites, different neurons can influence each other and lead to changes in the neural network. This is important for processing information and learning new material. This is possible because of neuron interactions that occur between neurons. As a result, specific neural activation patterns may arise due to the underlying morphology and connection patterns within the specified neural structures. These may subsequently be modified by morphological change imposed by the current representations. Progressively more complex patterns may arise through the manipulation of current neuronal structures by an organism's experience. Enbrainment While neurons are embedded within networks, these networks are further embedded within the brain as a whole. Neural networks do not work in isolation, such as in the modularity of mind perspective. Instead, different regions interact through feedback processes and top-down interactions, constraining and specifying the development of each region. For example, the primary visual cortex in blind individuals has been shown to process tactile information. The function of cortical areas emerges as a result of this sensory input and competition for cortical space. "This interactive specialization view implies that cortical regions might initially be non-specific in their responses but gradually narrow their responses as their functional specialization restricts them to a narrower set of circumstances." Circumstances within a person's life can result in head trauma. Instances such as concussions from sports and high-impact accidents can result in the brain colliding into the skull. This causes neurons to be damaged and the brain to be bruised. During this time, brain function is temporarily lost since the neurons are being damaged. Repeated instances of head trauma can lead to the development of lasting brain damage. Chronic stress causes long-term changes in the structure and function of the brain. This form of stress can cause an increase in myelin-producing cells and a decrease in neurons. Chronic stress reduces the amount of stem cells that grow into neurons, which may explain how it impacts learning and memory. Having said that, the neuronal network of a brain is continually changing due to plasticity. Chronic stress,