Cognitive Enhancement Increasing Memory Retention Brandi Shank

Memory Most cognitive functions involve memory to some extent Most cognitive functions involve memory to some extent Because of this, effects on cognition can often be attributed to changes in memory function Because of this, effects on cognition can often be attributed to changes in memory function Memory formation is a time-dependent process Memory formation is a time-dependent process Consolidation period is the process of memories moving from temporary to permanent state Consolidation period is the process of memories moving from temporary to permanent state Treatments given during the consolidation period enhance memory retention Treatments given during the consolidation period enhance memory retention White, 1998

Information Storage Extent of the brain’s storage capacity and limits on information processing are currently unknown Extent of the brain’s storage capacity and limits on information processing are currently unknown Crucial question for cognitive enhancement: Are the limits so large that there is plenty of room for improvement or are they so small that individuals with normal brain function are already performing close to them? Crucial question for cognitive enhancement: Are the limits so large that there is plenty of room for improvement or are they so small that individuals with normal brain function are already performing close to them? White, 1998

Limitations Evidence suggests that memory function is close to the limit imposed by brain’s information capacity Evidence suggests that memory function is close to the limit imposed by brain’s information capacity –Effects of memory enhancement on young subjects are limited –Increased in memory retention are more pronounced in older individuals or those with memory impairing diseases White, 1998

Limitations U-shaped dose-effect function demonstrated by memory enhancers U-shaped dose-effect function demonstrated by memory enhancers Suggests that there are limits to the amount of change that can be produced at each synapse and the amount of synapses relevant to memory Suggests that there are limits to the amount of change that can be produced at each synapse and the amount of synapses relevant to memory Attempts to increase dosages in order to exceed these limits have adverse effects on memory Attempts to increase dosages in order to exceed these limits have adverse effects on memory White, 1998

Memory Enhancing Substances Amphetamine Amphetamine Oestrogen and Testosterone Oestrogen and Testosterone Glucose Glucose Caffeine Caffeine Breast Milk Breast Milk Gray & Thompson, 2004; White, 1998

Amphetamine One of the most consistent and earliest memory enhancers One of the most consistent and earliest memory enhancers Study by Soetens, D’Hooge, and Hueting in 1993 using human subjects Study by Soetens, D’Hooge, and Hueting in 1993 using human subjects Experimental group received 10 mg shot of amphetamine, control group received saline injection Experimental group received 10 mg shot of amphetamine, control group received saline injection White, 1998

Amphetamine Word recall at 3 intervals: immediate, 20 minutes, and 24 hours Word recall at 3 intervals: immediate, 20 minutes, and 24 hours No statistically significant differences at first two intervals; about 30% on immediate and 10% at 20 minutes No statistically significant differences at first two intervals; about 30% on immediate and 10% at 20 minutes At the 24 hour interval, the experimental group recalled 8.5% while control group only recalled 6% At the 24 hour interval, the experimental group recalled 8.5% while control group only recalled 6% White, 1998

Oestrogen and Testosterone 1994 study by Dr. Barbara Sherwin on women who had undergone a total hysterectomy 1994 study by Dr. Barbara Sherwin on women who had undergone a total hysterectomy Subjects test on ability to recall words and paired associates 1 month prior to surgery Subjects test on ability to recall words and paired associates 1 month prior to surgery Randomly assigned to groups to receive hormone replacement therapy Randomly assigned to groups to receive hormone replacement therapy 4 groups: only oestrogen, only androgen, combination of oestrogen and androgen, and placebo 4 groups: only oestrogen, only androgen, combination of oestrogen and androgen, and placebo White, 1998

Oestrogen and Testosterone Memory tested later and those women who only received the placebo had significantly lower scores while those receiving hormone replacement therapy performed at the same level Memory tested later and those women who only received the placebo had significantly lower scores while those receiving hormone replacement therapy performed at the same level Lack of oestrogen hormones impairs memory but functioning can be restored with hormone therapy Lack of oestrogen hormones impairs memory but functioning can be restored with hormone therapy White, 1998

Oestrogen and Testosterone Effect of testosterone increase on males Effect of testosterone increase on males After 12 weeks of receiving testosterone enhancement subjects were given a cognitive function test After 12 weeks of receiving testosterone enhancement subjects were given a cognitive function test Test measured verbal memory, fine motor control, cognitive flexibility, spatial cognition, and mood Test measured verbal memory, fine motor control, cognitive flexibility, spatial cognition, and mood Experimental group received higher scores on spatial cognition Experimental group received higher scores on spatial cognition White, 1998

Glucose Study in 1994 by Benton, Owens, and Parker on female undergraduate students Study in 1994 by Benton, Owens, and Parker on female undergraduate students Blood glucose level measured, then the experimental group received a drink containing 50g of sugar, control group received a drink containing artificial sweetener Blood glucose level measured, then the experimental group received a drink containing 50g of sugar, control group received a drink containing artificial sweetener Worked on word manipulation activity for 20 minutes, then their blood glucose level was measured Worked on word manipulation activity for 20 minutes, then their blood glucose level was measured White, 1998

Glucose Memory test: listened to a list of 30 nouns and recall as many as possible in 2 minutes Memory test: listened to a list of 30 nouns and recall as many as possible in 2 minutes Test repeated after 20 minutes Test repeated after 20 minutes Subjects whose blood glucose level increased showed changes: Subjects whose blood glucose level increased showed changes: –small improvements if the increase was small –no effect or impaired if the increase was large White, 1998

Caffeine Study in the United Kingdom as part of a health and lifestyle survey Study in the United Kingdom as part of a health and lifestyle survey Subjects self-report coffee and tea consumption Subjects self-report coffee and tea consumption Significant effects on cognitive function seen as the result of caffeine consumption Significant effects on cognitive function seen as the result of caffeine consumption White, 1998

Caffeine Enhanced reaction time, verbal memory, and visuiospatial memory Enhanced reaction time, verbal memory, and visuiospatial memory Greater effects seen from larger doses Greater effects seen from larger doses Effects more pronounced in older subjects Effects more pronounced in older subjects White, 1998

Breast Milk Study of over 2,000 six-year olds Study of over 2,000 six-year olds 2 to 5 point gain in IQ for full-term infants 2 to 5 point gain in IQ for full-term infants 8 point gain in IQ for low birth weight infants 8 point gain in IQ for low birth weight infants Gray & Thompson, 2004

Sources Gray, J. R., & Thompson, P. M. (2004). Neurobiology of intelligence: science and ethics. Nature Reviews Neuroscience, 5, Gray, J. R., & Thompson, P. M. (2004). Neurobiology of intelligence: science and ethics. Nature Reviews Neuroscience, 5, White, N. M. (1998). Cognitive enhancement: an everyday event? International Journal of Psychology, 33, White, N. M. (1998). Cognitive enhancement: an everyday event? International Journal of Psychology, 33,