Exercise and spirit can stimulate the growth of new brain cells to reverse HD in humans. Seratonin and hormonal cycles also affect neurogenesis but the effects have not been studied in HD lab animals. There have been no studies of pregnant HD carriers.

The following study suggest circadian control of neurogenesis so it may help to spend time outside exercising when it feels best for you.

There is the possibility that the primary defect of HD is the inhibition of normally occurring neurogenesis. Researchers may be barking up the wrong tree by studying cell death in HD simply because naturally dying cells are not replaced in quantities to conserve brain volume. --Jerry

Posted to HDLighthouse: 03-Oct-2002 18:59 GMT HDL Update: Circadian Control of Neurogenesis.

Understanding Neurogenesis "These data raise the possibility that light-controlled rhythms are a primary regulator of neuronal proliferation", Barbera Beltz, Professor of Biological Sciences, Wellesley College.

The life-long addition of new neurons has been documented in many regions of the vertebrate and invertebrate brain:

1. Hippocampus of mammals (Altman and Das, 1965; Eriksson et al., 1998; Jacobs et al., 2000)
2. Song control nuclei of birds (Alvarez-Buylla et al., 1990)
3. Olfactory pathway of rodents (Lois and Alvarez-Buylla, 1994)
4. Insects (Cayre et al., 1996)
5. Crustaceans (Harzsch and Dawirs, 1996; Sandeman et al., 1998; Harzsch et al., 1999; Schmidt, 2001).

The possibility of persistent neurogenesis in the neocortex of primates is also being widely discussed (Gould et al., 1999; Kornack and Rakic, 2001). In these systems, an effort is underway to understand the regulatory mechanisms that control the timing and rate of neurogenesis:

1. Hormonal cycles (Rasika et al., 1994; Harrison et al., 2001)
2. Serotonin (Gould, 1999; Brezun and Daszuta, 2000; Beltz et al., 2001)
3. Physical activity (Van Praag et al., 1999)
4. Living conditions (Kemperman and Gage, 1999; Sandeman and Sandeman, 2000)

All influence the rate of neuronal proliferation and survival in a variety of organisms, suggesting that mechanisms controlling life-long neurogenesis are conserved across a range of vertebrate and invertebrate species.

The present article extends these findings by demonstrating circadian control of neurogenesis. Data show a diurnal rhythm of neurogenesis among the olfactory projection neurons in the crustacean brain, with peak proliferation during the hours surrounding dusk, the most active period for lobsters.

These data raise the possibility that light-controlled rhythms are a primary regulator of neuronal proliferation, and that previously-demonstrated hormonal and activity-driven influences over neurogenesis may be secondary events in a complex circadian control pathway.

Source: Department of Biological Sciences, Wellesley College, Goergen EM, et al. 03-Oct-2002

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