Many factors can lead to neuron death. This can happen immediately or gradually, through various mechanisms.
Physical Trauma and Injury
Damage to the brain and spinal cord, resulting from impacts to the head (shaking or hitting), strokes, or other forms of physical trauma, can kill neurons directly or indirectly. This often occurs by depriving neurons of the oxygen and nutrients essential for their survival. [Source: National Institute of Neurological Disorders and Stroke (NINDS), various news articles].
Neurodegenerative Diseases
Diseases like Alzheimer's disease progressively destroy neurons and their connections. In Alzheimer's, the exact mechanisms are complex but involve the buildup of abnormal proteins that damage neurons. [Source: National Institute on Aging (NIA)]. Amyotrophic lateral sclerosis (ALS) involves the release of toxins from astrocytes (star-shaped brain cells) that kill motor neurons. [Source: Columbia University Irving Medical Center, University of Massachusetts Medical School].
Toxins and Substance Abuse
Certain substances are neurotoxic, meaning they directly damage or kill neurons. Prolonged abuse of drugs like amphetamines, cocaine, and heroin can lead to irreversible brain damage and neuron loss. Similarly, excessive alcohol consumption can have detrimental effects. Even prolonged marijuana abuse may negatively impact brain function. [Source: Addiction Center, Step to Recovery].
Seizures
Seizures, characterized by abnormal brain activity, can cause neuronal death. The exact mechanisms through which seizures kill neurons are still under investigation but are believed to involve excessive excitation and oxidative stress. [Source: PubMed Central].
Microglia Activation
Microglia, immune cells in the brain, can become activated and, under certain conditions, release substances like TNFα, glutamate, and nitric oxide that are harmful to neurons. This process plays a significant role in several neurodegenerative diseases. [Source: ScienceDirect].
Apoptosis (Programmed Cell Death)
Some neuronal death is a natural, controlled process called apoptosis. This is a necessary part of brain development and maintenance. In certain circumstances, however, it may contribute to neuronal loss in disease states. [Source: PubMed].
Other Factors
Other factors, such as infection, genetic predispositions, and lack of sufficient blood flow, can also contribute to neuron death.
