1. Neural Plasticity and Disease
As the fundamental units of the brain, neurons function to integrate and transmit a myriad of signals across vast and complex networks. Neurons by definition are continually forming, eliminating, and modulating (strengthening and weakening) connections in response to the constant flow of information. In mediating and responding to activity, neurons, including their processes and synapses, must be plastic. Thus neural plasticity may then be defined as the ability of neurons and neural elements to adapt in response to intrinsic and extrinsic signals. As such, our ability to process and synthesize information, ultimately producing behavior, is dependent upon this neural plasticity [1]. It is therefore not surprising that dysregulation or disruption of neural plasticity is associated with neuropsychiatric and neurodegenerative disease.
Dynamic processes such as adult neurogenesis, the development of dendritic spines, and synaptic adaptations are included under the umbrella of neural plasticity and are essential to normal functioning. Aberrant neural production, connectivity, or transmission is invariably present under disease states, such as Alzheimer's disease, schizophrenia, or depression [2–5]. Each aspect of neural plasticity can independently and additively cause or contribute to the disease state. Thus, it is of fundamental importance to elucidate the neurological underpinnings of these disease states at the cellular level, in order to understand etiology and better develop effective treatment.