Cognitive enhancement

Treatment

Anatomy or system affected: Brain

Definition: An increase in one or more of the cognitive processes of the brain, including learning, memory, attention, perception, problem solving, and decision making.

Key terms:

agonist: a chemical that mimics or increases the effect of a neurotransmitter

antagonist: a chemical that inhibits or decreases the effect of a neurotransmitter

mnemonic: technique used to facilitate memory by modifying the way that information is learned

neuromodulator: a brain chemical that increases or decreases the effect of a neurotransmitter

psychostimulant: any drug that increases the overall excitability of neurons in one or more neural pathways

reaction time: the amount of time required to complete a task

transcranial direct current stimulation (tDCS): a technique that uses small electrodes placed on the surface of the scalp to excite or inhibit regions deep within the brain

Perspective and Prospects

Cognitive enhancement involves the use of a specific intervention to achieve the goal of improving one or more mental processes. The processes that may be enhanced include perception, attention, working memory, long-term memory, language, problem solving, and decision making. Some cognitive enhancers are also purported to increase intelligence.

There are many ways that people attempt to enhance cognition, including nutritional supplements, over-the-counter and prescription drugs, modified training paradigms, interactive technologies, and direct electrical stimulation of the brain. Although many anecdotal and popular accounts of how various substances and technologies can increase cognition exist, experimental and clinical evidence suggest that there are very few evidence-validated methods for achieving cognitive enhancement.

The ginkgo is one of the oldest surviving species of trees. The fan-shaped leaves of the Ginkgo biloba tree have been used in traditional Chinese medicine to boost memory for centuries. Though there is evidence that ginkgo leaf extract may have some memory-restoring effects for those elderly suffering from mild dementia or Alzheimer's disease, laboratory studies have failed to find any evidence for such an effect on cognition in normal, healthy individuals. Despite the lack of research support for ginkgo as a memory enhancer, it is still a popular supplement and is touted as an ingredient in so-called energy drinks.

Energy drinks are carbonated beverages that contain high levels of caffeine as well as other assorted ingredients that are purported to affect attention and learning. Along with ginkgo, the amino sulfonic acid taurine is a common ingredient in energy drinks. Despite claims that taurine and caffeine work together to enhance cognition, researchers have failed to find any consistent positive or negative effects of adding this substance to the diet. Indeed, when positive effects on cognition were observed, they were most often attributed to the effect of caffeine on the brain.

One of the most widely used cognitive enhancers, both today and historically, is the ubiquitous alkanoid caffeine. Caffeine is found in varying quantities in tea, coffee, soft drinks, energy drinks, and chocolate. This drug, which is classified as a psychostimulant, requires between twenty and forty-five minutes before the effects are experienced and has a half-life of five to six hours. Like most stimulants, caffeine increases the level of excitation within the brain. An antagonist of the neuromodulator adenosine, caffeine indirectly increases the release of the neurotransmitters dopamine and norepinephrine by decreasing the levels of inhibition on both.

There is general agreement that moderate levels of caffeine enhance alertness and attention and decrease reaction time, whereas high levels of caffeine have an impairing effect on attention. What is less clear is whether caffeine has any positive effect on learning and memory. The lack of consistency in experimental studies may reflect the complex way that caffeine intake, normal patterns of use (i.e., how much one normally ingests each day), and task difficulty and demands all interact.

Nicotine is another readily available substance that may have some mild cognitive-enhancing effects. This highly addictive compound, commonly found in tobacco, is an agonist of the neurotransmitter acetylcholine. The stimulating effects of nicotine on acetylcholine networks in the brain are likely responsible for the decreases in reaction time and slight increases in working-memory function that have been demonstrated.

Just like nicotine and caffeine, prescription drugs that have been reported to enhance cognition are psychostimulants. Both Ritalin (methylphenidate) and Adderall (amphetamine salts) act to increase excitation within the brain by increasing the release of dopamine. Most often prescribed to ameliorate the hyperactivity associated with attention deficit hyperactivity disorder (ADHD), these drugs have been abused by non-ADHD children and adults because of their ability to increase focus and positively impact long-term memory retention. Similarly, the anti-narcolepsy drug modafinil has gained notoriety due to its purported high level of abuse by college students and professionals striving to get ahead by working long hours. Some studies suggest that the abuse of prescription psychostimulant medications may have adverse long-term effects on the brain and other bodily systems.

Cognition may also be enhanced by non-pharmaceutical means, such as by manipulating the way that information is presented and processed. As was demonstrated by Hermann Ebbinghaus in 1885, the amount of time required to learn information may be reduced drastically if the learning trials are spread out across days rather than crammed together in one day. Similarly, mnemonics can greatly enhance the amount of information that can be learned and retrieved. Techniques such as visualizing items to be remembered, anchoring new information to existing memories, and chunking large numbers of items into meaningful units have all been shown to enhance learning and memory in both laboratory and real-life (e.g., classroom) settings.

Despite the fact that optimal results are seen when cognitive-enhancing techniques are used by individuals in face-to-face settings, some mnemonic and other cognitive-enhancing techniques have been integrated into computer-based “brain training” programs. Although these programs are based on neuroscientific and cognitive psychological research findings, there are few studies that have examined the effects of computer-based training on enhancing cognition directly. What studies have shown is that though there are often moderate enhancements for the specific games that are used as training (which are designed to enhance cognition in general), there is no evidence of transfer of the computer-developed skills to novel tasks, intelligence, or other areas of cognition. In the few studies that did show transfer effects outside the computer, it should be noted that the participants were required to train on the games for hours each day for several weeks. Such prolonged and time-consuming training regimens may be prohibitive for general use.

Rather than using computers and technology to train one's brain to become more efficient and accurate, a type of neurostimulation known as transcranial direct current stimulation (tDCS) can be used to directly stimulate portions of the brain by modifying the local electromagnetic fields in those regions. The basic technique dates back as far as the late eighteenth or early nineteenth century, when Italian physicist Giovanni Aldini reported having successfully treated "melancholy madness" (depression) with the application of low-intensity direct current to the brain. It was reinvestigated as a treatment for depression in the 1960s but eventually abandoned due to inconsistent results.

The modern form of tDCS was originally developed to aid recovery from brain injury, such as from a stroke, but was soon discovered to have the potential to enhance learning and cognition in healthy adults as well. The stimulation is facilitated by attaching two sponge electrodes to the scalp and applying a small direct current (DC, as opposed to alternating current, AC). A few studies have reported that tDCS may enhance attention, language abilities, various forms of long-term learning and memory, and working memory. However, some of those studies have shown that when certain cognitive processes are enhanced by tDCS, others may then be impaired. In addition, a large-scale meta-analysis published in 2015 found that despite the positive results reported in previous studies of tDCS in healthy adults, there was no evidence of any significant improvement in any area of cognitive functioning.

While advances in medicine and technology continue to introduce novel ways to attempt to enhance cognition, bioethicists debate whether cognitive enhancement should be pursued in the first place. Though cognitive enhancers such as nicotine and caffeine have been present for centuries, direct stimulation of the brain and abuse of prescription drugs have prompted a reexamination of the morality concerning cognitive enhancement, and even of what it means to be human.

Bibliography

Buchanan, Allen. Better Than Human: The Promises and Perils of Enhancing Ourselves. New York: Oxford UP, 2011. Print.

Feilden, Tom. "'Human Enhancement' Comes a Step Closer." BBC News. BBC, 26 Jan. 2012. Web. 18 Mar. 2015.

Harris, Mark. "Brain Hackers Beware: Scientist Says tDCS Has No Effect." IEEE Spectrum. IEEE, 21 Jan. 2015. Web. 18 Mar. 2015.

Hildt, Elisabeth, and Andreas G. Franke, eds. Cognitive Enhancement: An Interdisciplinary Perspective. Dordrecht: Springer, 2013. Print.

Rekart, Jerome L. The Cognitive Classroom: Using Brain and Cognitive Science to Optimize Student Success. Lanham: Rowman, 2013. Print.

Smith, M. Elizabeth, and Martha J. Farah. “Are Prescription Stimulants ‘Smart Pills’? The Epidemiology and Cognitive Neuroscience of Prescription Stimulant Use by Normal Health Individuals.” Psychological Bulletin 137.5 (2011): 717–41. Print.

Zaghi, Soroush, et al. "Noninvasive Brain Stimulation with Low-Intensity Electrical Currents: Putative Mechanisms of Action for Direct and Alternating Current Stimulation." Neuroscientist 16.3 (2010): 285–307. Print.