What is Neurogenesis?

Neurogenesis – the creation of new brain cells

The human brain is the most complex organ ever created by nature. With 100 billion neurons and an even greater number of connection points, it exceeds the performance of any supercomputer to date. If you were to string together all the nerve fibres and axons of a human brain, they would have a length of 5.8 million kilometres, which in turn would correspond to 145 times the circumference of the earth at the equator! One of the most significant features of this organ is its remarkable ability to learn. The formation of neurons is called neurogenesis.

Neurogenesis is essential for brain development

Neurogenesis is a fascinating process in which new nerve cells or neurons are formed in the brain. This process is essential for the development of the brain throughout life and plays a crucial role in its function and adaptability. The importance of neurogenesis is manifold. It enables the formation of new connections between neurons and is crucial for maintaining brain function throughout life. Neurogenesis contributes to brain plasticity, i.e. the ability to adapt to new situations and challenges. It also plays an important role in learning and memory processes and is associated with mood regulation. There is even evidence that a lack of neurogenesis plays a role in certain mental disorders, such as depression.

Profileration, migration and differentiation – development of neurons is a multi-step process.

Neurogenesis goes through different stages to form new neurons. It begins with proliferation, where neural stem cells and progenitor cells in the brain are divided to generate a larger number of cells. These cells have the potential to differentiate into different types of neurons depending on the needs of the brain. Proliferation is followed by migration, where the newly formed cells move to their final destinations in the brain. During this phase, the cells receive signals from their environment that help them find the right path and integrate into the appropriate brain regions. Differentiation is the next step, during which the progenitor cells turn into mature neurons. These neurons develop specific properties, such as the formation of axons and dendrites, which are necessary for communication between the cells. The cells then join the neuronal circuits and begin to make synaptic connections with other neurons.

Synaptogenesis: New neurons form functional synapses for communication.

Finally, the newly formed cell enters the phase of synaptogenesis, in which it forms functional synapses to communicate with other cells in the brain. In brief, synaptogenesis refers to the process of formation and development of synapses between neurons in the nervous system. Synapses are the junctions where information is transmitted from one neuron to the next neuron. Synaptogenesis is an essential step for the correct functioning of neuronal circuits and plays a crucial role in learning, memory and adaptation processes in the brain.

Various factors influence functional neurogenesis

The number of newly formed neurons in the brain of a healthy person varies and depends on various factors such as age, lifestyle and genetic factors. For example, regular physical exercise can promote the formation of new neurons, while chronic stress or lack of sleep can negatively influence the process of neurogenesis. In general, neurogenesis decreases in the course of life.

Neurogenesis in patients suffering from Alzheimer’s dementia.

Neurogenesis still takes place in Alzheimer’s patients, but the patterns and efficiency of this process are altered compared to healthy people. Studies have shown that neurogenesis may be impaired in Alzheimer’s patients. In some cases, a reduced number of neural stem cells and progenitor cells have been observed, which can lead to reduced formation of new neurons. In addition, these newly formed neurons may have difficulty migrating, differentiating and integrating into existing neural networks. Despite the impaired neurogenesis in AD patients, some studies indicate that in certain brain areas, the remaining neural stem and progenitor cells show an increased rate of cell division. This increased proliferation may be the brain’s response to the progressive cell loss and synaptic damage caused by Alzheimer’s disease. But it is likely that the increased proliferation alone may not be enough to fully compensate for the negative effects of the disease. In many cases, the newly formed neurons are probably unable to integrate effectively into existing neuronal networks, which could limit their functionality and potential therapeutic effect. The study of neurogenesis in Alzheimer’s patients is an active area of research that should contribute to a better understanding of the disease mechanisms and the identification of possible therapeutic approaches.