A seminar on the effects of hormones on memory By Hamish Whistler

Hormones’ Role in the Body Like all other living creatures of this world, we are made up of living cells that interact with each other mainly through chemical means. Hormones are regulating chemicals in the body, their complex interaction with organs and cells help shape our bodies, behaviour and the way we think. One such effect is that of the role of hormones and their interaction with our memory…

Stress Hormones and Memory The Pituitary Adrenal Axis –Cells in the hypothalamus secrete CRF (Corticotrophin Releasing Factor) in stressful situations. –The CRF is transported to the Anterior Pituitary –The Anterior Pituitary is stimulated to produce ACTH (Adrenocorticotropic Hormone) –ACTH controls the Adrenal Cortex and stimulates it to produce Cortisol.

Stress Hormones and Memory The Pituitary Adrenal Axis (continued) –Cortisol exerts a negative feed back effect on the hypothalamus that inhibits further release of CRF by the hypothalamus –The cycle continues on until the hypothalamus stops producing CRF i.e. the stressful situation as passed.

Stress Hormones and Memory

Glucocorticoids (cortisol and corticosterone) –A study by Newcomer et al (1999) showed that high doses of Cortisol (suggesting high levels of stress) can have a negative impact on verbal declarative memory.

Stress Hormones and Memory Glucocorticoids (cortisol and corticosterone)

Stress Hormones and Memory Example Implications – The exam room –In examination settings we often stress and reach high levels of arousal, this could lead to a detrimental effect on recall in exam performance. –In the situation of an exam, not being able to remember can stress you further starting a downwards cycle into a memory block, doing easier questions first and calming down the best way out. –More mild amounts of stress are shown to have minimal or insignificant effects on performance, some arousal may even be better for memory recall.

Estrogen and Memory It is usually more of a concern to woman reaching menopause whose natural production of estrogen runs out when their ovaries stop functioning Men convert testosterone into estrogen in the brain and therefore never normally totally run out One effect of menopause mentioned by woman is the reduction in memory performance This is also reported by men with prostate cancer who have had their testosterone levels dropped to treat the cancer…See a trend?

Estrogen and Memory Research towards woman : –Decline in memory is usually in source memory and some verbal declarative memory, not so much item memory. –Research in long term estrogen replacement therapy in woman suggest that estrogen use (when combined with progesterone) may temper age-related cognitive decline by helping to maintain functions typically used in the frontal lobes.

Estrogen and Memory Research towards woman continued : –Further more conclusive research and research into other areas of memory are underway but is based on longitudinal studies and results will not be available for a few years.

Estrogen and Memory Alzheimer's disease and woman: –Estrogen treatment has also given successful results in the treatment of Alzheimer’s disease, making symptoms less severe and if taken before the onset of, used as a preventative. –Brain cells that are often damaged from Alzheimer’s disease have been discovered to have receptors for estrogen and nerve-growth-factor suggesting an interaction of the two.

Estrogen and Memory Research towards men: –Men with prostate cancer which have had their testosterone levels reduced for cancer treatment have received estrogen therapy and have had improvements on verbal memory but not on working memory. –Very little research has been done in this area (that I could find) and it is only the beginnings.

Estrogen and Memory Research towards animals: –Research in mice has shown that estrogen enhances the formation of dendrites and axons between brain cells –The roll of estrogen is still not clear, most studies suggest it has more to do with particular memory aspects. An example is social recognition memory in mice.

Estrogen and Memory Research towards animals Continued: –One study showes doses of Estrogen to give two fold increases in spines (dendrites and axons) as shown in the left slide versus normal spines growth in the right slide in brain cells taken from a rat embryo.

Closing Notes Most of the research in these areas is new and controversial, many studies contradict each other etc. Further research will expose the wider range of hormones interacting and allow for better diagnosis and treatments of disorders to become available. Its not a matter of if, but rather when Thank you to those of you still awake for listening THE END