Researchers explore various drug compounds and their potential to enhance human cognition, including attention, learning, and higher-order thinking.
While some progress has been made, many questions remain.
Key Facts:
- Several drug compounds show potential to mildly enhance some cognitive functions like attention, learning, and memory. These include stimulants, wakefulness agents, and compounds that affect memory encoding.
- It is less clear if these compounds improve higher, integrated cognitive functions in healthy individuals under real-world conditions. Their effects may be limited to increasing efficiency rather than fundamentally expanding cognitive capabilities.
- More research is needed into the complex cell biology underlying cognition to identify new drug targets. Initial results with compounds affecting glutamate receptors and cortical communication appear promising.
- Social and ethical concerns around fairness, safety, personal freedom must be considered regarding the use of cognitive enhancers. Their long-term psychological and societal impacts remain unknown.
Source: Pharmacol Biochem Behav.
The Search for “Smart Drugs” & Cognitive Enhancement
The idea of a “smart pill” that can enhance human intelligence and cognition has long fascinated scientists and the general public alike.
Research over the past few decades has identified several drug compounds with potential cognition-enhancing effects.
However, significant questions and challenges remain regarding their efficacy, especially concerning higher cognitive functions under normal real-world conditions.
As researchers learn more about the neurobiology underlying cognition, new avenues emerge for plausible drug targets.
But cognition is breathtakingly complex, incorporating attention, learning, memory, reasoning, decision-making and other higher mental functions.
It is mediated by intricate cellular mechanisms across distributed networks of brain regions.
Successfully enhancing such a multifaceted phenomenon pharmacologically remains extraordinarily difficult.
This article summarizes current scientific understanding of drug-based cognitive enhancers, including their psychological mechanisms of action, effects on cellular processes, and translation from animal models to human outcomes.
It also touches on some social and ethical implications of putative “smart pills.”
Using State Manipulation to Enhance Cognition
Initial efforts to pharmacologically improve cognition focused on manipulating general arousal and vigilance.
The basic rationale was that attention and wakefulness provide a foundation for higher cognitive operations.
Agents like methylphenidate and modafinil exemplify this approach.
Methylphenidate (Ritalin) is a stimulant that increases dopamine and noradrenaline levels.
It has pronounced arousal effects reminiscent of amphetamines.
In animals, it improves attention on relatively simple tasks, spatial working memory under specific conditions, and encoding of some types of memory.
However evidence in healthy humans is mixed concerning consistent benefits to complex cognitive performance, according to recent meta-analyses.
Modafinil is a wakefulness agent originally developed to treat narcolepsy.
Researchers noticed it appeared to enhance attention and working memory as well, via effects on catecholamine and histamine systems.
But again, benefits do not clearly extend to integrated cognitive function in normal individuals.
In general, while improvements to attention and wakefulness may carry over somewhat to downstream operations, these state-dependent effects appear limited regarding overall cognition.
They are also clouded by side effects of the drugs on mood and arousal.
LTP: Memory & Cortical Mechanisms in Animal Models
Another avenue of research concerns targeting specific cognitive operations like memory and executive functions more directly, rather than manipulating their preconditions like attention.
One approach focuses on strengthening memory encoding, the initial cellular changes underlying memory formation.
Dozens of compounds affecting receptors for acetylcholine, glutamate, norepinephrine and other neurotransmitters have shown promise enhancing encoding processes in animal models.
Many operate by regulating long-term potentiation (LTP), an increase in synaptic strength widely implicated in learning and memory.
For example, so-called “ampakines” act on glutamate receptors to facilitate LTP and improve various memory measures in rodents.
But again translation to human cognition has proved difficult.
Enhanced encoding may not transfer to better memory or reasoning in contexts demanding complex, integrative processing.
Differences in underlying neurobiology across species also hinder translation.
Nonetheless, some promising indications exist. For instance ampakines improved short-term memory in patients suffering from schizophrenia, suggesting benefits extend beyond tightly-controlled lab tests.
Rather than targeting specific operations, a radical possibility is direct modulation of higher cortical networks underlying complex cognitive functions themselves.
Glutamate is the major excitatory neurotransmitter in cortical communication, making its receptors intriguing drug targets.
Positive allosteric modulators of glutamate receptors have recently shown some initial promise improving integrated functions like executive control and working memory in animal tests.
For instance, ampakines allowed rhesus monkeys to excel at a challenging short-term memory and decision-making task, beyond normal limits.
Imaging indicated expanded activation of key prefrontal and temporal networks.
Similar cortical enhancement has also been observed with nicotinic agonists affecting glutamate signaling.
This cortical expansion may be the key to fundamentally enhancing mental capabilities, comparable to cognitive gains produced over evolution by increased neocortex size.
Smart Drugs in Animal Models vs. Humans
Many issues complicate translation of cognitive enhancers from animal studies to human trials however.
Rats and monkeys rely more heavily on certain evolutionarily older structures for learning and memory.
For instance the hippocampal memory system differs functionally across species of different brain sizes.
Targets successfully manipulated in smaller brains may thus prove less pivotal in humans.
Human cognition also incorporates immensely more contextual encoding, cross-referencing, strategic processing etc. compared to laboratory animal tests focused heavily on rote learning.
Memory encoding likely imposes a smaller bottleneck on these elaborative operations.
Optimizing it pharmacologically then provides little overall benefit to complex cognition.
Subtle differences in receptor distribution and cell types across cortical areas also hinder translation.
Researchers are now developing new behavioral tests in animals that better approximate components of human cognition, to better model drug effects.
Attention-demanding signal detection and memory retrieval tasks show particular promise for cross-species translation.
Studies should also move beyond supervised rote learning to incorporate unsupervised learning in richer environments, emulating real-world cognition.
For instance virtual reality systems can provide controlled yet highly complex spaces for humans and animals to explore freely, over hours or days.
Quantitative outcome measures then gauge learning, relationships detected, rules inferred etc.
This naturalistic self-directed learning aligns well with demands on human cognition.
Combined with imaging, detailed neural signatures of enhancement can be inferred beyond standardized test performance alone.
Ethical & Social Implications of Boosting Cognition
Discussions around cognitive enhancers also must consider their societal impacts regarding issues of fairness, access, unintended consequences etc.
For one, widespread use risks creating an uneven playing field.
Those able to afford smart pills, or whom they affect most strongly, may gain significant academic and workplace advantages over peers.
Their still unknown long-term effects also raise safety concerns.
Perhaps the most profound impacts however stem from the possibility of expanding fundamental cognitive capabilities.
Suppose modulating cortical communication can actually augment intelligence and mental faculties beyond normal limits, as initial results hint.
How could society integrate individuals who then conceptualize the world in radically advanced, altered ways?
Sudden new abilities could profoundly disrupt society to some extent.
And once exposed to enhanced cognition, people may prove highly reluctant to revert to thinking within conventional boundaries.
Proactively addressing such revolutionary potential requires vigorous discussion around appropriate policies and safeguards.
But researchers also stress that, fundamentally, all innovations allowing the mind to transcend current limitations – from language to books to computers – invariably transform society in unpredictable ways as well.
With judicious, evidence-based implementation, newly emerging intelligences could also bring welcome solutions to current problems, or convey perceiving our world and universe with greater insight and nuance than ever imaginable today.
The breathtaking possibilities and risks intrinsic to such cognitive frontiers call for thoughtful, inclusive dialogue alongside rigorous science.
Ongoing mysteries in deciphering cognition’s neurobiology will likely constrain practical enhancement to relatively modest increments in the near future however.
But past radical innovations consistently built on chains of humble steps toward understanding.
The accelerating quest for the secrets of mental capacity holds unfathomable potential to alter the trajectory of human progress and imagination in the decades and centuries ahead.
Emerging Trends in Cognitive Enhancement Research & Development
The field of cognitive enhancers is rapidly evolving, with exciting new trends shaping the future of how we might improve human cognition.
These developments not only promise more effective and precise interventions but also open doors to personalized cognitive enhancement strategies:
Targeted Drug Development: Modern research is moving towards creating drugs that are more specific in their action, aiming to influence particular cognitive functions while minimizing side effects. This specificity could lead to more effective treatments with fewer overall health risks.
Personalized Cognitive Enhancement: The burgeoning field of genomics is lending insights into how individual genetic differences affect responses to cognitive enhancers. This personalized approach could lead to treatments tailored to an individual’s genetic makeup, maximizing efficacy and minimizing adverse effects.
Non-pharmacological Interventions: Boosting cognition without medication or drugs.
- Transcranial Magnetic Stimulation (TMS): A non-invasive procedure that uses magnetic fields to stimulate nerve cells in the brain.
- Transcranial Direct Current Stimulation (tDCS): Another non-invasive technique that applies a low, constant current to the brain via electrodes on the head.
These methods are explored as alternatives or complements to drug therapies, offering cognitive enhancement without the systemic impact of drugs.
AI and Machine Learning in Cognitive Research: Artificial intelligence is revolutionizing cognitive enhancer research. By analyzing vast datasets, AI and machine learning can uncover new drug targets and provide deeper insights into complex cognitive functions.
Gut-Brain Axis Exploration: An intriguing area of research is the relationship between gut health and brain function. Understanding how gut microbiota influence cognition and mood could lead to novel cognitive enhancers that work by modulating the gut-brain axis.
These trends not only highlight the dynamic nature of cognitive enhancer research but also point towards a future where cognitive enhancement could become more effective, personalized, and broadly accessible.
References
- Study: The Likelihood of Cognitive Enhancement
- Authors: Lynch et al. (2012)
