After providing all the funding for The Brain from Top to Bottom for over 10 years, the CIHR Institute of Neurosciences, Mental Health and Addiction informed us that because of budget cuts, they were going to be forced to stop sponsoring us as of March 31st, 2013.

We have approached a number of organizations, all of which have recognized the value of our work. But we have not managed to find the funding we need. We must therefore ask our readers for donations so that we can continue updating and adding new content to The Brain from Top to Bottom web site and blog.

Please, rest assured that we are doing our utmost to continue our mission of providing the general public with the best possible information about the brain and neuroscience in the original spirit of the Internet: the desire to share information free of charge and with no adverstising.

Whether your support is moral, financial, or both, thank you from the bottom of our hearts!

Bruno Dubuc, Patrick Robert, Denis Paquet, and Al Daigen

Monday, 17 December 2012
Neurogenesis and Depression

The processes leading to the many different illnesses that can affect people’s psychic equilibrium are still hotly debated. Often, these processes involve multiple contributing factors, which is why there are so many different hypotheses about them. In the case of depression, for example, one of the best known is the monoamine hypothesis, which associates the disease with underactivity of certain neurotransmitters. such as serotonin.

Several research laboratories are now working on a more recent hypothesis about the cause of depression, involving a phenomenon that was first confirmed in humans in the late 1990s: neurogenesis, meaning the birth of new neurons in the adult brain. The starting point for this hypothesis is that these young neurons seem to show greater plasticity and are found only in certain parts of the brain, such as the dentate gyrus of the hippocampus, that are associated with emotions.

Researchers have shown for example, that stress, which is an aggravating factor in depression, also reduces neurogenesis in the hippocampus. while antidepressants, which often improve the symptoms of depression, also increase neurogenesis.  Even the relatively long time needed for antidepressants to take effect (around 3 to 6 weeks) might reflect the time needed for the neurons created by neurogenesis to mature and become functional.

Thus many phenomena converge to support the idea that a reduction in the rate of neurogenesis in the hippocampus may help to accentuate the symptoms of depression, or at least the cognitive ones. A recent study has also confirmed the involvement of the glucocorticoid receptor in the cascade of biochemical reactions that is caused by an SSRI and that encourages the differentiation of new neurons in the hippocampus.

i_lien New neurons and a new therapeutic target
i_lien Chronic stress, neurogenesis and depression
a_exp Antidepressants increase human hippocampal neurogenesis by activating the glucocorticoid receptor

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