About Functional Neurogenesis
This site is centered around the function of adult neurogenesis in the dentate gyrus of the hippocampus, including discussion of scientific research papers, methods and protocols, and other trends or observations about the field. However, since we cannot truly understand the function of adult hippocampal neurogenesis without also studying behavior, plasticity, development etc., I will invariably comment on findings outside of the adult neurogenesis literature, that are interesting or relevant.
Functional Neurogenesis is driven by the fact that there are many great websites and blogs devoted to neuroscience, but there are hardly any devoted to specialized disciplines, limiting discussion to meetings, email, and the slow process of peer-review publishing. I hope I can do something to fill this void. And maybe make people laugh a little bit.
I have to give credit to Michael Drew for helping to get Functional Neurogenesis off the ground.
About Jason Snyder
I did my undergraduate and graduate training in the Department of Physiology at the University of Toronto. While I am interested in the output of the system (behavior) and underlying mechanisms (synaptic function, circuit activity), it is the relationship between these different levels of function that is central to my long-term goal of understanding the role of adult neurogenesis in memory and mood.
I did my graduate work in the lab of Martin Wojtowicz and found that newborn neurons have enhanced synaptic plasticity relative to older neurons. Since the hippocampus is the center of the universe when it comes to memory I changed my direction and found that adult neurogenesis is particularly important for long-term spatial memory. As a postdoc in Heather Cameron’s lab at the National Institutes of Health / National Institute of Mental Health I made the switch from rats to mice and, in doing so, noticed that some aspects of neurogenesis didn’t quite match up. For example, some studies (in rats) reported that new neurons contribute to behavior by 2-3 weeks of age whereas other studies (in mice) reported that new neurons are not integrated into the circuitry until several weeks later. I therefore decided to systematically compare the two and this ended up being one of my favorite studies, perhaps only because my hypothesis was correct: I found that young neurons in mice are slower to mature, less likely to survive, less likely to be activated during behavior, and are less important for contextual fear conditioning than in rats.
One of the most prominent stories in the adult neurogenesis field is its potential involvement in depressive behavior. However, the fact that numerous studies found that reducing adult neurogenesis did not lead to a depressed phenotype argued against this hypothesis. I was drawn to this question when several of my experiments suggested that new neurons may play a role in regulating stress and emotion rather than learning. For example, in one study I found that when learning a stressful spatial memory task (water maze), immature neurons were activated primarily in the ventral, or more emotional, portion of the hippocampus while mature neurons were activated in the dorsal, spatial, region. I therefore directly investigated the potential role for new neurons in the regulation of stress and emotion, finding that neurogenesis-deficient mice have elevated glucocorticoids and depression-like behavior, primarily after exposure to acute stressors. This provided the first direct support for the neurogenesis hypothesis of depression.
I spent 2012 in Toronto in the lab of Paul Frankland.
(get in touch – email@example.com, Twitter)
Snyder JS, Ferrante SF, Cameron HA (2012) Late Maturation of Adult-Born Neurons in the Temporal Dentate Gyrus. PLoS ONE, 7(11): e48757.
Snyder JS, Clifford MA, Jeurling SI, Cameron HA (2012) Complementary activation of hippocampal-cortical subregions and immature neurons following chronic training in single and multiple context versions of the water maze. Behav. Brain Res., 227: 330–9.
Snyder JS, Cameron HA (2012) Could adult hippocampal neurogenesis be relevant for human behavior?. Behav. Brain Res., 227: 384-90.
Snyder JS, Soumier A, Brewer M, Pickel J, Cameron HA (2011) Adult hippocampal neurogenesis buffers stress responses and depressive behaviour. Nature, 476: 458-61.
Snyder JS, Ramchand P, Rabbett S, Radik R, Wojtowicz JM, Cameron HA (2011) Septo-temporal gradients of neurogenesis and activity in 13-month-old rats. Neurobiol. Aging, 32(6):1149-56.
Snyder JS, Choe J, Clifford M, Jeurling S, Hurley P, Brown A, Kamhi J, Cameron HA (2009) Adult-born hippocampal neurons are more numerous, faster maturing and more involved in behavior in rats than in mice. [high res] J. Neurosci. 29: 14484-14495.
Snyder JS, Radik R, Wojtowicz JM, Cameron HA (2009) Anatomical gradients of adult neurogenesis and activity: Young neurons in the ventral dentate gyrus are activated by water maze training. Hippocampus 19: 360-370.
Snyder JS, Glover LR, Sanzone KM, Kamhi JF, Cameron HA (2009) The effects of exercise and stress on the survival and maturation of adult-generated granule cells. Hippocampus 19: 898-906.
Winocur G, Wojtowicz JM, Sekeres M, Snyder JS, Wang S (2006) Inhibition of neurogenesis interferes with hippocampus-dependent memory function. Hippocampus 16: 296-304.
Snyder JS, Hong NS, McDonald RJ, Wojtowicz JM (2005) A role for adult neurogenesis in long-term memory. Neuroscience 130: 843-852.
Snyder JS, Kee NJ, Wojtowicz JM (2001) Effects of adult neurogenesis on synaptic plasticity in the rat dentate gyrus. J. Neurophysiol. 85: 2423-2431.
Snyder JS, Wojtowicz JM (2012) Correlations between different stages of neurogenesis emerge after learning. Figshare: http://dx.doi.org/10.6084/m9.figshare.93067
Snyder JS, Grigereit L, Brewer M, Pickel J, Cameron HA (2011) A transgenic rat model for reducing neurogenesis. Figshare:
Snyder JS, Sanzone K, Soumier A, Cameron HA (2011) Stress can increase or decrease anxiety depending on the timing of the stressor. Figshare: http://dx.doi.org/10.6084/m9.figshare.89656