The multifaceted disorder that is depression resists simple explanations. Research, including that on brain function, leads to a variety of theories attempting to explain the causes and mechanisms of depression. They provide valuable information and can provide a starting point for actions to be taken to confront this mental health disorder.
Neurogenic theory of depression
Theories of depression may focus on selected aspects of the disorder. The most widespread theory of depression is the neurochemical theory (monoamine theory), focusing on disorders in the balance of neurotransmitters from the brain. This theory states that depression results from a deficiency of monoamines like serotonin, dopamine and norepinephrine at brain synapses. Based on this theory, increasing the amount and availability of the aforementioned neurotransmitters is considered effective in treating depression. And indeed, antidepressants that increase neurotransmitter concentrations have been shown to be effective in treating depression. One of the newer theories of depression is the theory of neurogenesis and neuroplasticity, which focuses on the brain’s regenerative abilities and neuronal plasticity. This theory explains that the weakening of the brain’s processes of creating new neurons and the decline in plasticity leads to the onset of adverse symptoms of depression. It should be noted that the theories of depression are not mutually exclusive and can complement each other. You can read more about them in this article.
Neurogenesis and neuroplasticity
Neurogenesis is the process of formation, maturation, migration and integration of new neurons into the brain’s neuronal network. Neurogenesis occurs in the brain, and importantly, in adult brains as well. We have only known about it since the 1990s, at which time studies were published indicating that neurogenesis takes place not only in the prenatal period and in children, but also in adults. The process of birth of new neutrons occurs continuously throughout life, but with varying intensity and only in certain areas. It takes place in the dentate bend of the hippocampus and the olfactory bulb. Neurogenesis has an important repair function after brain damage, and is important for learning and memory processes. There are reports that new neurons are involved in regulating responses to stress and anxiety and may protect against the development of depression. The speed of new neuron formation varies from person to person, and the intensity of the process can be modulated. Stress, abuse of various substances, including alcohol, cause a decrease in the intensity of neurogenesis. Being under stress for a long time causes proliferative activity (strong cell division) to be inhibited in the hippocampal region, and neuronal survival decreases. This is because hippocampal cells are sensitive to the stress hormone cortisol. As a result, the volume of the hippocampus decreases and its functioning becomes impaired. Low levels of neurogenesis bring cognitive impairment, vulnerability to stress, anxiety and depression.
Neuroplasticity is the brain’s ability to reorganize. An efficient brain needs to respond to changing circumstances, it needs to change, to adapt, and it can do so thanks to neuroplasticity. Neuroplasticity allows for the formation of new connections between neurons in the brain. It allows for partial regeneration when injury or stroke occurs. Neurogenesis can be considered part of the reorganization process, although neuroplasticity can involve an already existing network. The theory linking depression to the phenomenon of brain plasticity points to a reduction in this ability in depressed individuals. Not only is there less neurogenesis in depression, but there is also a loss of neuroplasticity. This means that the depressed brain is less able to change, less flexible. Reduced brain plasticity, and therefore reduced adaptability, may be the reason why it is difficult to recover from depression. With low neuroplasticity, the low responsiveness of neurons to stimuli, it is difficult to change mood and thinking patterns. The problem with depression is not so much the lowered mood, but the fact that it is impossible to recover from it smoothly.
Enhance neurogenesis and neuroplasticity
The role of the process of neurogenesis is not entirely clear, but since in the adult it is mainly limited to the formation of the hippocampus, it must be relevant to the role it plays, which is adaptation, memory consolidation and emotion regulation. The potential for neuroplasticity and neurogenesis can be used to treat depression. There are reports that new neurons are more plastic and prone to form new connections. Newly formed cells can mediate the treatment of depression, because they have characteristics that favor the desired neuroplastic changes, they are the ones used preferentially in learning processes. In depression, neurons are less responsive to stimuli, the new neurons help increase brain plasticity, which gives the brain a chance to recover from depression. That being said, the question is how to increase neurogenesis and brain plasticity to overcome depression and increase quality of life?
Neurogenesis and neuroplasticity can be supported directly and indirectly through:
- Pharmacological interventions with SSRI drugs that increase serotonin levels in the brain. Antidepressants affect the proliferation, maturation and survival of new neurons in the dentate cortex of the hippocampus. It turns out that serotonin not only improves mood, but also increases adult neurogenesis.
- Psychotherapeutic interventions unlock neurogenesis by increasing motivation for action. They use new neurons to change cognitive patterns, as new neurons and new activity transform neuronal networks, so plasticity is increased. With psychotherapy, the desired change in neuronal patterns is possible, resulting in a change in the patient’s functioning.
- Stress reduction through relaxation, meditation, mindfulness, which lowers the neuron-killing hormone cortisol. This hormone not only inhibits the formation of neurons, but is also harmful to those already in existence. There is an effective way to relax and reduce stress using VR. The VR TierOne GO relaxation goggles relieve stress that destroys neurogenesis and neuroplasticity. Different from daily monotony and a safe virtual environment, pleasant visual, audio and emotional stimuli become a stimulus for beneficial changes in the brain. These can counteract the onset of depression.
- An enriched environment providing positive stimuli stimulates neurogenesis and increases the survival rate of new neurons. This is important because only some of the new cells will survive and be incorporated into the network. VR-based interventions can enhance neurogenesis and neuroplasticity. VR TierOne’s enriched therapeutic environment engages the senses and is emotionally stimulating. Immersive form and exploration of a new virtual space rich in symbols, colors and details can promote neurogenesis activity and neuroplasticity. The VR TierOne medical device with virtual therapy is used as a supportive treatment for depression. This carefully constructed virtual experience is helpful in introducing the therapy participant to needed activity for health. It breaks through inactivity and stimulates pro-health changes.
- Physical activity promotes neurogenesis, as it increases the level of neutrophin-released BDNF – this substance is a growth factor essential for cell development, nourishes cells, increases their proliferation and survival. It is an important mediator of synaptic plasticity in the hippocampus, which plays a key role in memory processes. However, it is not recommended to train too intensively, which decreases BDNF secretion, which will result in a decrease in neurogenesis.
- A diet of calorie restriction and intermittent fasting increases BDNF production, which promotes neurogenesis.
- Sleep hygiene is of infinite importance, sleep helps lower stress levels, allows the resulting neurons to survive and strengthens the connections between them.
Promoting neurogenesis and neuroplasticity of the brain requires integrated measures. It is important to foster brain regeneration processes to maintain health, and if necessary, use therapies to restore the brain’s potential for change. VR technology has a special ability to engage at the mental level, so it becomes important in supporting brain function and mental health.
