Researchers discover the source of new neurons in brain's hippocampus

on 31 March 2019
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Subgranular layer of the dentate gyrus

Deep within your brain, some little critters called neuronal stem cells, are hard at work helping you build memories and, hopefully, a very happy and enjoyable life. The secret to that life though is while they are hard at work; you shouldn't be. . . . 

The name of the game is relaxation and this little snippet of wisdom is the mental version of "an apple a day, keeps the Doctor away!" What I mean by that, is, most people know that an apple a day keeps the Dr away, yet, despite that, very few eat the apple a day. Similarly, many people know that relaxation is good for you but they don't do that either! The bulk of our neural stem cells grow in a part of the hippocampus called the dentate gyrus. And what they seem to be saying here is that these stem cells come from the same embryonic population that existed when we were in our mother's womb and which then replicate themselves throughout our lifetime, from embryo to death, so to speak! Although the centre for our sense of smell, the olfactory bulb is a new one on me, so some more research to do? 

However, there are actually two main centres in the brain that produce neural stem cells, (1) the subgranular zone, a layer between the hilus and granule cell layer of the dentate gyrus (part of the hippocampal formation, as illustrated in the image above) and (2) the subventricular zone - SVZ - (part of the ventricular system of the forebrain). During the embryonic phase, all of our brain's neurons and glia develop from the ventricular zone. After birth, they eventually migrate to the SVZ, for the rest of our life. 

The most important factor, relating to the work that I do as a clinical hypnotherapist, is in the first area, the hippocampus. This is because of the ways in which stress and anxiety disorders disrupt neural stem cell production in the dentate gyrus of the hippocampus. This is important because these new stem cells play a crucial role in the formation of new memories and learning and, if we are too stressed, for too long, the hippocampus can actually shrink (hippocampal atrophy). So, obviously, the answer is to become more calm and relaxed and one of the most efficacious ways to do that is through hypnosis and hypnotherapy.

In my hypnotherapy clinic, here in Singapore, I use all of my training, skills and experience to help you discover the source of the issue and then, via hypnosis, a psychotherapeutic intervention is delivered. Hypnotherapy effectively delivers this straight into the deeper levels of your brain's language, what we call the subconscious mind. From there, via sleep states and the proliferation of PGO (ponto-geniculo-occipital) waves which occur during sleep states and also during the hypnotic experience! Subsequently, through neural stem cell migration, new memories are created. A process called long term potentiation is involved, which strengthens the synaptic strength of this inter-neuronal transmission, and from this process. new memories eventually become new habitual behaviours and this explains the permanence of hypnotherapy. For the most part, all behaviour is memory dependent, if you don't have a memory of something then it cannot be repeated, with, perhaps, the exception of reflexes! So, in order to create new behaviours or habits or simply change or modify old ones, you need to keep your daily build-up of neuronal stem cells flowing. Like I said, one of the best ways to do that, is by learning how to be calm and relaxed as often as is possible. Hypnosis (post-therapy0, will really help you to master and maintain this peaceful and harmonious state!

However, there are a few things that might be helpful for you to know because one of the challenges that any therapist faces, is the difference in the way our individual brain is wired. Over the years I have had many clients presenting with anxiety and stress disorders, some respond very quickly to treatment and others take a little longer. Having said that, it is fair to say that each client experiences hypnosis slightly differently and one might think that those who respond well, as in, more susceptible to hypnosis, would be the ones who get quicker relief to their anxiety and the ones who have to work a little harder at hypnosis (as in a few more sessions or methods of delivery) are the ones that take longer . . . but that isn't always the case, there just doesn't seem to be any specific parallel to the way one person experiences hypnosis and the development of a stress/anxiety related issue. So, there has to be something directly related to the way their brain responds to sensory stimuli, that elicits a disorder. This, makes the anomaly between their condition and the way they experience hypnosis unpredictable to a degree but that is where the training and experience of the hypnotist come into play?

Some of the factors that make one person more susceptible to stress and anxiety could be genetic. It is known that the children of mothers who experienced a lot of anxiety/stress during their pregnancy are potentially more likely to be predisposed to anxiety related issues. However, our brain develops more because of environmental factors, i.e. our experiences, living environment etc. As children, we non-consciously develop strategies that allow us to cope. However, these are childlike strategies made by a child's brain and while they often work for us as children, they may not be at all useful to us as adults. It is often the degree to which we react to these childlike strategies, and how they relate to emotionally perceived survival matters, that eventually dictates our potential to maladapt as we develop from a child to adolescent, to adult. This goes some way to explaining why some very mature and responsible adults behave like children when anxious or stressed! Other factors that lead to the development of mental illness, can be the possibility of brain lesions, which could be a consequence of a current/previous head injury or maybe an infection or disease or being exposed to trauma, be it via man-made or natural events (terrorist attacks, earthquakes) or even cumulative trauma, e.g. being told you are stupid, useless, no good etc. over and over.

So, the causes of anxiety disorders are varied and many and because of that, the way in which our brain is willing to respond to any particular type of therapeutic treatment, is somewhat dependent on the initial causes and developmental processes within and across the brain are equally varied. The threat detection system, within our brain, is primarily involved in trying to maintain as close to normal a living environment as possible. However, how it does this, is by actually creating a very defensive style of living, which is anything but calm or relaxed! Therefore, the more we can discover about the nature and development of an individual client's anxiety, the greater the prospect there is, for a complete and lasting recovery, and, quite likely, without the need for any medication!

If you are suffering from unwanted and unnecessary anxiety or stress, now is the time to seek help, hypnotherapy can provide you with that!

Hypnotherapy stands out as one of the most effective strategic life management methods there is, especially in its ability to promote clear thinking and good states of mental wellness. The behaviours that make life challenging are often a result of too much stress, too little sleep and too little by way of clarity! So, to get or take back control of your mind and your life, it makes perfect sense to use a methodology that addresses the subconscious mind's role in perpetuating negative, vague and ambiguous states of mind. Hypnosis helps us to create calm relaxing states of mind that make life work better! If you would like to address any concerns you have in this direction, or, if you just want to make your life feel better, then why not make an appointment for a Free Consultation? Hypnosis gives you the ability to have a good life! 

The objective here is to help people understand how and why we become illogically trapped into irrational emotional experiences that may actually be happening for reasons different to that which we would imagine! If you want to know more about how Hypnotherapy can help you; why not make an appointment for a Free Consultation?

For more information on the Free Consultation - Go Here or to book your Free Consultation today, you can do so here

The Research:

It was once believed that mammals were born with the entire supply of neurons they would have for a lifetime. However, over the past few decades, neuroscientists have found that at least two brain regions -- the centres of the sense of smell and the hippocampus, the seat of learning and memory -- grow new neurons throughout life.

Researchers from the Perelman School of Medicine at the University of Pennsylvania have shown, in mice, that one type of stem cell that makes adult neurons is the source of this lifetime stock of new cells in the hippocampus. Published this week in Cell, these findings may help neuroscientists figure out how to maintain youthful conditions for learning and memory, and repair and regenerate parts of the brain after injury and ageing.

"We've shown for the first time, in mammals, that neurons in the dentate gyrus of the hippocampus grow and develop from a single population of stem cells, over an entire lifespan," said senior author Hongjun Song, PhD a professor of Neuroscience. "The new immature neurons are more flexible in making connections in the hippocampus compared to mature neurons, which is paramount for healthy learning, memory, and adjusting the mood."

The researchers showed that the neural stem cells they found had a common molecular signature across the lifespan of the mice. They did this by labelling neural stem cells in embryos when the brain was still developing and following the cells from birth into adulthood. This approach revealed that new neural stem cells with their precursor's label were continuously making neurons throughout an animal's lifetime.

"This process is unique in the brain," said co-senior author Guo-li Ming, MD, PhD, a professor of Neuroscience. "In the hippocampus, these cells never stop replicating and contribute to the flexibility of the brain in mammals."

This capacity is called plasticity, which is the brain's ability to form new connections throughout life to compensate for injury and disease and to adjust in response to new input from the environment. Ming likens the process of new neuron growth in the hippocampus to adding new units into the circuitry of the brain's motherboard.

The teams' next steps will be to look for the same neural stem cells in other mammals, most importantly in humans, starting the search in post-mortem brain tissue, and to investigate how this population of neural stem cells are regulated.

This work was funded by the National Institutes of Health (P01NS097206, R37NS047344, R35NS097370, R01MH105128), EMBO, and the Swedish Research Council.

Story Source:

Materials provided by the University of Pennsylvania School of Medicine. Note: Content may be edited for style and length.

Journal Reference:

Daniel A. Berg, Yijing Su, Dennisse Jimenez-Cyrus, Aneek Patel, Nancy Huang, David Morizet, Stephanie Lee, Reeti Shah, Francisca Rojas Ringeling, Rajan Jain, Jonathan A. Epstein, Qing-Feng Wu, Stefan Canzar, Guo-Li Ming, Hongjun Song, Allison M. Bond. A Common Embryonic Origin of Stem Cells Drives Developmental and Adult Neurogenesis. Cell, 2019; DOI: 10.1016/j.cell.2019.02.010

Cite This Page:

University of Pennsylvania School of Medicine. "Researchers discover the source of new neurons in the brain's hippocampus: Findings extend understanding of how a continuous supply of neurons throughout life is connected with learning and memory." ScienceDaily. ScienceDaily, 28 March 2019. <>.