Cognitive Cognitive EnhancementEnhancement

Increasing Memory RetentionIncreasing Memory Retention

Brandi ShankBrandi Shank

MemoryMemory

Most cognitive functions involve memory to Most cognitive functions involve memory to some extentsome extent

Because of this, effects on cognition can often Because of this, effects on cognition can often be attributed to changes in memory functionbe attributed to changes in memory function

Memory formation is a time-dependent processMemory formation is a time-dependent process Consolidation period is the process of memories Consolidation period is the process of memories

moving from temporary to permanent statemoving from temporary to permanent state Treatments given during the consolidation Treatments given during the consolidation

period enhance memory retention period enhance memory retention

White, 1998

Information StorageInformation Storage

Extent of the brain’s storage capacity Extent of the brain’s storage capacity and limits on information processing and limits on information processing are currently unknownare currently unknown

Crucial question for cognitive Crucial question for cognitive enhancement: Are the limits so large enhancement: Are the limits so large that there is plenty of room for that there is plenty of room for improvement or are they so small improvement or are they so small that individuals with normal brain that individuals with normal brain function are already performing close function are already performing close to them?to them?

White, 1998

LimitationsLimitations

Evidence suggests that memory Evidence suggests that memory function is close to the limit imposed function is close to the limit imposed by brain’s information capacity by brain’s information capacity – Effects of memory enhancement on Effects of memory enhancement on

young subjects are limitedyoung subjects are limited– Increased in memory retention are more Increased in memory retention are more

pronounced in older individuals or those pronounced in older individuals or those with memory impairing diseaseswith memory impairing diseases

White, 1998

LimitationsLimitations

U-shaped dose-effect function U-shaped dose-effect function demonstrated by memory enhancers demonstrated by memory enhancers

Suggests that there are limits to the Suggests that there are limits to the amount of change that can be amount of change that can be produced at each synapse and the produced at each synapse and the amount of synapses relevant to amount of synapses relevant to memory memory

Attempts to increase dosages in order Attempts to increase dosages in order to exceed these limits have adverse to exceed these limits have adverse effects on memoryeffects on memory

White, 1998

Memory Enhancing Memory Enhancing SubstancesSubstances

AmphetamineAmphetamine Oestrogen and TestosteroneOestrogen and Testosterone GlucoseGlucose Caffeine Caffeine Breast Milk Breast Milk

Gray & Thompson, 2004; White, 1998

AmphetamineAmphetamine

One of the most consistent and One of the most consistent and earliest memory enhancersearliest memory enhancers

Study by Soetens, D’Hooge, and Study by Soetens, D’Hooge, and Hueting in 1993 using human Hueting in 1993 using human subjectssubjects

Experimental group received 10 mg Experimental group received 10 mg shot of amphetamine, control group shot of amphetamine, control group received saline injectionreceived saline injection

White, 1998

AmphetamineAmphetamine

Word recall at 3 intervals: Word recall at 3 intervals: immediate, 20 minutes, and 24 hoursimmediate, 20 minutes, and 24 hours

No statistically significant differences No statistically significant differences at first two intervals; about 30% on at first two intervals; about 30% on immediate and 10% at 20 minutesimmediate and 10% at 20 minutes

At the 24 hour interval, the At the 24 hour interval, the experimental group recalled 8.5% experimental group recalled 8.5% while control group only recalled 6%while control group only recalled 6%

White, 1998

Oestrogen and TestosteroneOestrogen and Testosterone

1994 study by Dr. Barbara Sherwin on 1994 study by Dr. Barbara Sherwin on women who had undergone a total women who had undergone a total hysterectomy hysterectomy

Subjects test on ability to recall words and Subjects test on ability to recall words and paired associates 1 month prior to surgerypaired associates 1 month prior to surgery

Randomly assigned to groups to receive Randomly assigned to groups to receive hormone replacement therapy hormone replacement therapy

4 groups: only oestrogen, only androgen, 4 groups: only oestrogen, only androgen, combination of oestrogen and androgen, combination of oestrogen and androgen, and placebo and placebo

White, 1998

Oestrogen and TestosteroneOestrogen and Testosterone

Memory tested later and those Memory tested later and those women who only received the women who only received the placebo had significantly lower placebo had significantly lower scores while those receiving scores while those receiving hormone replacement therapy hormone replacement therapy performed at the same levelperformed at the same level

Lack of oestrogen hormones impairs Lack of oestrogen hormones impairs memory but functioning can be memory but functioning can be restored with hormone therapy restored with hormone therapy

White, 1998

Oestrogen and TestosteroneOestrogen and Testosterone

Effect of testosterone increase on Effect of testosterone increase on malesmales

After 12 weeks of receiving After 12 weeks of receiving testosterone enhancement subjects testosterone enhancement subjects were given a cognitive function testwere given a cognitive function test

Test measured verbal memory, fine Test measured verbal memory, fine motor control, cognitive flexibility, motor control, cognitive flexibility, spatial cognition, and moodspatial cognition, and mood

Experimental group received higher Experimental group received higher scores on spatial cognition scores on spatial cognition

White, 1998

GlucoseGlucose

Study in 1994 by Benton, Owens, and Study in 1994 by Benton, Owens, and Parker on female undergraduate studentsParker on female undergraduate students

Blood glucose level measured, then the Blood glucose level measured, then the experimental group received a drink experimental group received a drink containing 50g of sugar, control group containing 50g of sugar, control group received a drink containing artificial received a drink containing artificial sweetenersweetener

Worked on word manipulation activity for Worked on word manipulation activity for 20 minutes, then their blood glucose level 20 minutes, then their blood glucose level was measuredwas measured

White, 1998

GlucoseGlucose

Memory test: listened to a list of 30 Memory test: listened to a list of 30 nouns and recall as many as possible in 2 nouns and recall as many as possible in 2 minutesminutes

Test repeated after 20 minutesTest repeated after 20 minutes Subjects whose blood glucose level Subjects whose blood glucose level

increased showed changes:increased showed changes:– small improvements if the increase was small improvements if the increase was

smallsmall– no effect or impaired if the increase was no effect or impaired if the increase was

large large

White, 1998

CaffeineCaffeine

Study in the United Kingdom as part Study in the United Kingdom as part of a health and lifestyle surveyof a health and lifestyle survey

Subjects self-report coffee and tea Subjects self-report coffee and tea consumptionconsumption

Significant effects on cognitive Significant effects on cognitive function seen as the result of function seen as the result of caffeine consumptioncaffeine consumption

White, 1998

CaffeineCaffeine

Enhanced reaction time, verbal Enhanced reaction time, verbal memory, and visuiospatial memorymemory, and visuiospatial memory

Greater effects seen from larger Greater effects seen from larger dosesdoses

Effects more pronounced in older Effects more pronounced in older subjects subjects

White, 1998

Breast MilkBreast Milk

Study of over 2,000 six-year oldsStudy of over 2,000 six-year olds 2 to 5 point gain in IQ for full-term 2 to 5 point gain in IQ for full-term

infantsinfants 8 point gain in IQ for low birth weight 8 point gain in IQ for low birth weight

infantsinfants

Gray & Thompson, 2004

SourcesSources

Gray, J. R., & Thompson, P. M. (2004). Gray, J. R., & Thompson, P. M. (2004). Neurobiology of Neurobiology of intelligence: science and ethics. intelligence: science and ethics. Nature Reviews Nature Reviews Neuroscience, 5Neuroscience, 5, 471-482. , 471-482.

White, N. M. (1998). Cognitive enhancement: an White, N. M. (1998). Cognitive enhancement: an everyday event? everyday event? International Journal of International Journal of

Psychology, Psychology, 3333, 95-105., 95-105.