Neurogenesis

Neuroplasticity: New Advances in the Field

Until recently, researchers believed that the adult brain did not have much capacity to adapt, grow and learn novel tasks. Recent research has changed that belief, as the 2024 study at Stanford University has published findings that demonstrate otherwise in stroke patients. 

Neurogenesis is the creation of new neurons in the brain. This occurs from neural stem cells, as they create progenitor cells. In the central nervous system, which consists of your brain and spinal cord, these stem cells become astrocytes and oligodendrocytes. In adults, the majority of neurogenesis occurs in the hippocampus, specifically the dentate gyrus. These newly generated neurons receive electric signals from synapses, extending to axons. Through these processes, plasticity is promoted, allowing the brain to learn new functions. Learning and memory are the main cognitive functions that are acquired by the brain. 

Neurogenesis: neurons formed from progenitor cells

The Role of Neurogenesis in Alzheimer's Disease

Since changes in neurogenesis are observed in the early stages of Alzheimer’s, it is proposed that increased production of neurogenesis could slow the disease progression. Increasing exercise and cognitive activity can promote neurogenesis, which can lead to a reduced risk of developing Alzheimer’s. The regions in which neurogenesis occurs can also change with age, affecting the neocortex v. hippocampus. Neurogenesis occurs in the dentate gyrus of the hippocampus, one of the first regions of the brain that are affected in Alzheimer’s disease.

Neurogenesis that is not regulated properly can actually impair neuroplasticity and prevent recovery from brain injury or neurodegeneration. Adult hippocampus neurogenesis (AHN) has been demonstrated to lead to loss of function, in addition to gain of function studies. The amount of AHN that is present in AD patients is affected by SNAP receptor protein-protein interactions (Tobin et al. 2019) that affects cognitive function. 

Pattern separation memory is a crucial part of episodic memory, which represents the function of separating and storing different experiences in the brain. The dentate gyrus is crucial for pattern separation memory, which is often impaired in patients that have mild cognitive function, often a precursor to AD. Impaired neurogenesis may play a large role in the cognitive decline in Alzheimer’s disease.