TMS (Transcranial Magnetic Stimulation) is a technique utilized to stimulate specific regions of the brain via electromagnetic induction. The regions that receive stimulation typically depend on an individual’s reason for using TMS. For example, individuals using TMS for the treatment of depression may administer electrical pulses to the left prefrontal cortex, while individuals using TMS for migraines may administer the pulses to a completely different region.
Following administration of these magnetically-induced electrical pulses, previously underactive neurons and neural networks become activated. In addition, various levels of neurotransmitters such as serotonin, dopamine, norepinephrine, etc. are thought to fluctuate significantly following treatment. As a result of the complex cascade of neural effects associated with TMS, some speculate that the technique could be used to enhance cognitive function.
Preliminary evidence suggests that TMS can enhance cognition among those with psychiatric conditions (e.g. depression) and neurological disorders (e.g. Alzheimer’s disease). It could also be speculated that as TMS protocols undergo extensive research, researchers may discover ways in which it could be used to enhance cognitive performance among those with normative (or even already “above average”) capabilities. Should technology continue to advance at a rapid pace along with TMS protocol research, you may be able to one day purchase an “at-home” TMS device (or something similar) for cognitive enhancement.
How TMS May Enhance Cognitive Function (Mechanism of Action)
The specific mechanisms of action responsible for TMS-induced cognitive enhancement aren’t fully understood. However, TMS is thought to enhance cognitive function primarily via cortical modulation and by increasing efficiency within specific neural networks responsible for a given cognitive process. Other ways in which TMS may facilitate cognitive enhancement are discussed below.
Activity optimization: Targeted TMS can increase brain activity in specific regions that are known to enhance certain cognitive tasks. Furthermore, TMS is also capable of toning down activity in regions that are working against the “enhancing” regions. In other words, TMS can attenuate activity in circuits that are impairing cognition and bolster activity in regions that are enhancing it. Regions that aren’t necessary for a specific cognitive task can be essentially “turned off” to free up resources for other areas.
Brain waves: Some studies suggest that manipulating brain waves with TMS can enhance cognitive function on certain tasks. One study was conducted in which participants underwent rTMS manipulation of alpha frequencies. Researchers administered a TMS protocol designed to promote alpha desynchronization and noted that it effectively improved tasks performance. It should be speculated that strategic manipulation of other frequencies may prove beneficial for deriving cognitive enhancement from TMS.
Cortical modulation: It is known that TMS modulates activity within certain cortical regions, thereby regulating neural excitability. Excess neural excitability is associated with impaired cognitive function and is common among those with neurodegenerative diseases. Administration of TMS appears to prevent excess neural excitability, thereby improving cognitive performance.
Correct frontal dysfunction: Certain individuals (particularly those with psychiatric or neurological illnesses) tend to exhibit dysfunctional activity within the prefrontal cortex. For example, someone with depression may be dealing with hypoactivation of the left prefrontal cortex and hyperactivation of the right prefrontal cortex. In addition, connectivity between certain deeper regions and the prefrontal cortex may be impaired. Targeted TMS is capable of correcting dysfunction within the prefrontal cortex to enhance cognition.
Neural efficiency: Stimulation of specific brain regions with TMS can improve neural efficiency. The neurons and neural networks in a specific region become activated by TMS, whereas prior to the TMS, they may have been underactive. This increased activation means that the brain doesn’t need to work as hard to perform cognitive tasks associated with that particular region – the cortex is more efficient.
Regional activation: TMS can be used to activate certain regions, thereby activating underutilized neural pathways, neurons, neuroplastic changes, and neurotransmission. Someone with deficient activation in a certain region may derive noticeable benefit from a TMS intervention aimed at increasing activation.
- Neural pathways: Certain neural pathways associated with peak cognitive performance may be underactive among individuals with deficits. TMS can reactivate certain neural pathways to promote cognitive enhancement.
- Neuroplasticity: TMS can prompt neuroplastic changes within the brain by altering connectivity between circuits and regions – this may bolster cognition.
- Neurotransmission: Upon stimulation with TMS, neurons typically release an action potential which alters concentrations of neurotransmitters. Increases in deficient neurotransmitter levels may enhance cognitive function.
Stimulate specific circuitry: Studies have shown that researchers can manipulate cognitive function based on the specific area targeted with TMS, as well as the parameters employed. For example, stimulating the right DL-PFC at a specific frequency is thought to stimulate a subset of cortical circuitry (or “loop”) that enhances cognition. On the other hand, stimulation of the left DL-PFC at specific frequencies may activate a separate “loop” that impairs cognition. As further research surfaces, we will know more about specific loops.
TMS for Cognitive Enhancement (Research)
The majority of research conducted with TMS involves using the technique as a diagnostic tool or for the treatment of various neurological conditions. That said, there is significant preliminary evidence to believe that the technique can be used to improve cognitive function across broad spectrum of individuals – regardless of whether they are cognitively impaired or “healthy.” Included below is a summary of the studies suggesting that TMS could enhance cognition.
2015: A review published in 2015 investigated the cognitive effects of TMS among individuals diagnosed with major depression. Individuals with major depression often struggle with significant “brain fog,” inattentiveness, memory deficits, and other forms of cognitive impairment. Although various antidepressant augmentation strategies can be prescribed to address cognitive impairment (e.g. Adderall for depression), these options are associated with unwanted side effects.
Researchers scoured the scientific literature for studies testing the efficacy of repetitive TMS for cognitive enhancement among those with refractory depression. To be included in the review, the studies were required to be an original publication in a peer-reviewed journal and specifically investigate the cognitive effects of rTMS among those with depression. A total of 22 publications met inclusion criteria for the review.
Results from the included studies indicated that there was a trend of rTMS enhancing aspects of cognition (among those with depression). It is important to understand that some studies included in the review noticed that rTMS actually caused greater cognitive impairment. Due to the fact that most studies included in the review had small sample sizes and poor designs – it is difficult to draw any firm conclusions.
Authors of the review concluded that rTMS should be considered a “promising” technique for cognitive enhancement among those with treatment-resistant depression. It is likely that rTMS could enhance cognition among those with depression, but effective protocols for cognitive enhancement should be distinguished from those that are ineffective. In this review, it is likely that protocol variability may have heavily influenced results.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/25925699
2015: A study published in 2015 assessed the efficacy of TMS for the treatment of mild cognitive impairment (MCI). Mild cognitive impairment is a condition that significantly ups an individual’s risk for dementia and neurodegeneration. Researchers proposed that high-frequency rTMS administered to the left DL-PFC (dorsolateral prefrontal cortex) may improve memory function among individuals with mild-cognitive impairment.
A total of 34 elderly individuals with mild-cognitive impairment were recruited for the study. These individuals were split into 2 groups: one received rTMS and the other received a sham-TMS procedure for a total of 10 sessions. The TMS was administered at a frequency of 10 Hz with 110% motor threshold and 2,000 pulses per session. Prior to the study, all individuals were assessed with the Rivermead Behavioral Memory Test (RBMT).
The RBMT was administered following the 10th session, as well as after a one-month post-treatment follow-up. Results suggested that individuals receiving the rTMS experienced a significant improvement in memory compared to those receiving the sham-TMS. What’s more promising is the fact that this memory enhancement was maintained at one-month follow-ups.
Authors suggested that TMS may be effective to delay memory deterioration among those with mild-cognitive impairment. It should be noted that other protocols may warrant testing and that this was a very small-scale study. Further research with larger sample sizes are necessary to confirm preliminary findings.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/26160997
2015: A review published in 2015 discussed TMS as both a diagnostic tool and cognitive enhancer. Authors suggested that TMS can be used to create functional maps of various brain structures and networks. They noted that repetitive TMS (transcranial magnetic stimulation) is capable of modulating cognitive function.
Due to the fact that cognitive function can be modulated with TMS, researchers speculated that the technique could be used as a cognitive enhancer among those with healthy brains and among those with various neurological disorders (e.g. Alzheimer’s). Future research may want to determine whether TMS should be used differently among healthy individuals for cognitive enhancement compared to those with neurological disorders.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/26092315
2014: A review published in 2014 assessed the preliminary efficacy of using TMS for the enhancement of cognitive function in healthy humans. Authors noted that TMS is capable of modulating an array of cortical networks, and as a result of this modulation, it can enhance speed and accuracy on intellectual tasks. Studies have suggested that healthy individuals receiving TMS can enhance executive processing, motor skills, and perceptual functions.
Authors believe that the cognitive enhancing effects from TMS are a result of increased cortical efficiency and modulation of various cortical networks. In other words, after receiving TMS an specific region of the brain functions more efficiently than usual, making it easier to complete certain cognitive tasks. The modulation of cortical networks implies that TMS helps reduce activity in regions that aren’t conducive to cognition, while increases activity in regions that promote optimal cognition.
It was noted that TMS could be used to improve cognition among those with neurological and psychiatric disorders – and also improve learning speed among healthy individuals. Researchers note that it is unclear as to which TMS protocols are likely to work best for cognitive enhancement, as well as how the effects could be amplified and maintained for an extended period of time. Further research is necessary to investigate the efficacy of certain protocols and to fully elucidate the mechanisms of TMS on cognitive function.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/23770409
2014: A study published in 2014 analyzed the efficacy of TMS for the treatment of mild cognitive impairment (MCI) and Alzheimer’s disease. Researchers discuss that TMS techniques can be used as non-invasive diagnostic tools to understand cortical excitability as well as neuroplastic alterations that occur among those with neurodegenerative diseases. Despite being used as a diagnostic tool, it is well-known to alter brain activity when administered repetitively.
Since individuals with mild-cognitive impairment and/or Alzheimer’s disease typically have overactive right dorsolateral prefrontal corticies (DL-PFCs), TMS can be administered to reduce activity in this region. Research has already been conducted to determine whether TMS administered to inhibit right DL-PFC activity would improve aspects of cognition. Results indicated that inhibition of right DL-PFC activity improved verbal and nonverbal recognition performance.
On the other hand, stimulating the right DL-PFC with TMS to increase activity resulted in impaired recognition performance. Therefore, it can be suggested that overactivity of the right dorsolateral prefrontal cortex plays a major role in cognitive impairment. Other research has shown that targeting DL-PFCs in either the right or left hemisphere can significantly improve accuracy on naming and language performance tasks.
It was mentioned that usage of rTMS (repetitive transcranial magnetic stimulation) can modulate excitability within the cortex and alter long-term neuroplasticity among those with neurodegeneration. Preclinical evidence indicates that TMS is able to enhance cognitive function among individuals with both mild cognitive impairment and/or Alzheimer’s disease. That said, significantly more research is necessary to confirm preclinical findings.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/24506061
2014: It is well known that individuals with schizophrenia have impaired cognitive function. As a result of debilitating cognitive symptoms, many pharmaceutical companies are developing new schizophrenia medications specifically to treat cognitive impairment. The cognitive deficits such as psychomotor slowing, memory problems, and attentional deficits can make it difficult for an individual with this disorder to maintain a steady job.
Furthermore, cognitive deficits are often accompanied by negative symptoms including: avolition, blunted emotion, and depression. Preliminary evidence from a study published in 2014 suggests that TMS could enhance cognitive function and ameliorate negative symptoms among those with schizophrenia. Researchers investigated the effect of “deep TMS” on among 30 individuals with schizophrenia compared to a placebo (sham-TMS) for negative and cognitive symptoms.
The deep-TMS was administered 20 times per day at 20 Hz (120% motor threshold) to the prefrontal cortex. Results from the study indicated that deep-TMS significantly reduced negative symptoms (-7.7), but not significantly enough compared to the sham-TMS (-1.9). Further research is warranted to determine whether deep or standard TMS may be useful as a cognitive enhancing adjunct among those with schizophrenia.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/24829210
2014: A report published in 2014 discussed the usage of TMS and tDCS (transcranial direct current stimulation) among individuals with neurodegenerative diseases. Researchers conducted a review to determine whether TMS and tDCS has therapeutic potential for the treatment of an array of conditions such as: Alzheimer’s disease, Parkinson’s disease, dementia with Lewy bodies, and mild-cognitive impairment. They assessed over 700 publications, but only 32 fit inclusion criteria for their review.
Results from their research indicated that TMS and tDCS were likely to be effective for the treatment of certain symptoms associated with neurodegenerative diseases. It was noted that future research is warranted to understand whether TMS is more effective for certain neurodegenerative diseases compared to others. Furthermore, it is necessary to determine optimal stimulation parameters for specific neurodegenerative diseases.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/25478032
2012: In effort to elucidate the neural underpinnings of cognitive flexibility, researchers utilized TMS. Since cognitive flexibility is associated with activity in the striatum and its interaction with the prefrontal cortex, researchers used rTMS to stimulate a specific region of the prefrontal cortex. Their rTMS protocol stimulated the prefrontal cortex to facilitate an increase in dopamine within the striatum.
To fully understand what was occurring within the participant’s brains, fMRI neuroimaging scans were collected prior to rTMS and post-TMS during the performance of a “switching” task to test cognitive flexibility. This specific switching task was heavily reliant upon a region known as the putamen, which influences activity within the striatum.
Results indicated that TMS stimulation detrimentally affected putamen signaling and decreased connectivity between the prefrontal cortex and striatum – resulting in decreased cognitive flexibility on tasks that required putamen signaling. Researchers concluded that it is possible to manipulate various cognitive functions based on the circuits targeted with TMS.
Authors suggest that TMS may be favorable to pharmacological interventions for cognitive enhancement due to specificity of effects. TMS can be used to target specific circuits, whereas pharmacological interventions often elicit widespread neurophysiological effects. The key seems to be understanding which circuits to target and parameters to utilize for strategic enhancement of a particular aspect of cognition.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/22514324
2010: A study published in 2010 discussed the effect of high-frequency rTMS on cognitive function. High-frequency rTMS is thought to depolarize neurons in the region targeted with stimulation, and elicit an array of secondary effects in nearby regions involved in emotion and behavior. Previous research had suggested that administration of high-frequency rTMS to the left DL-PFC (dorsolateral prefrontal cortex) was most likely to impair cognitive function.
Researchers conducted a review to investigate the effect of high-frequency rTMS (administered to the prefrontal cortex) on cognitive function. The review incorporated studies among healthy individuals or those with pathological conditions – between 1999 and 2009. Results revealed that rTMS at high frequencies (10 Hz, 15 Hz, 20 Hz) administered to the left DL-PFC was most likely to impair cognitive function after 10 to 15 sessions.
That said, researchers noted some differences in results between those with psychiatric disorders and healthy individuals. Those with healthy brain functioning typically end up with greater impairment as a result of high-frequency left DL-PFC stimulation compared to those with psychiatric conditions. Authors noted that further research is warranted to understand the mechanisms associated with TMS-induced cognitive impairment.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/19859782
2008: A paper published in 2008 discussed that TMS can be used to either increase or decrease excitability within various regions of the brain. Researchers suggested that TMS could be used to enhance the formation of new memories, improve motor performance, as well as motor learning tasks among healthy individuals. The evidence compiled by researchers indicated that TMS can facilitate short-lasting motor improvements, but the mechanisms associated with these improvements aren’t fully understood.
Authors concluded with the hypothesis that TMS may be able to modulate learning and memory formation among those who are healthy, as well as individuals with neurological disorders. Since this report is relatively dated, we already know that learning and memory functions can be manipulated via TMS. However, we still don’t understand the mechanisms associated with the manipulation, and we haven’t fully figured out how to prolong the effect of TMS-induced cognitive enhancement.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/19802336
2008: A paper in 2008 discussed the potential applications of TMS and tDCS. Both modalities of neural stimulation have allowed neuroscientists to better understand the inner workings of the brain. With new stimulation protocols emerging for both TMS and tDCS, researchers may be able to strategically manipulate desired cognitive processes. In other words, a process like memory formation can be enhanced with the right TMS protocol.
That said, extensive experimentation will be necessary to unveil protocols that effectively enhance a specific cognitive process such as memory formation. These protocols will need to be distinguished from others that may enhance a completely different aspect of cognition. Further, it will be necessary to understand how to maintain beneficial cognitive effects from TMS, as well as to avoid protocols that may impair cognitive functions.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/18374276
2005: It is well-established that Parkinson’s disease is associated with cognitive deficits. A subset of those with Parkinson’s disease also struggle with depression. Those with depression and Parkinson’s are known to have more severely impaired cognition than those without depression.
A study published in 2005 assessed the cognitive enhancing potential of two proven antidepressant treatments: Prozac (20 mg/day) and rTMS to the left prefrontal cortex (15 Hz, 110% motor threshold, 10 sessions daily). A total of 25 individuals with Parkinson’s disease and depression participated in the study, receiving either: rTMS + placebo (Group 1) or Prozac + sham-TMS (Group 2).
All individuals were assessed with a neuropsychological battery at baseline, at 2 weeks post-treatment, and 8-weeks post-treatment. Results indicated that patients in both Group 1 and Group 2 experienced significant improvement in cognitive function as evidenced by a Stroop task, Wisconsin Card Sorting Test, and Hooper Visual Organization Test. This suggests that rTMS is as effective as an SSRI for improving certain aspects of cognitive function among those with Parkinson’s disease.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/15895421
2004: A paper published in 2004 noted that TMS can be used to improve performance in healthy individuals, as well as individuals with neurological and/or psychiatric disorders. Authors mentioned that there are various types of TMS that can be used to alter various brain processes including: single-pulse, paired-pulse, and repetitive. They mention the fact that the effects of TMS on the brain appear to be transient and the mechanisms responsible for these effects are poorly understood.
It was suggested that TMS could be used as a rehabilitation strategy for those with motor deficits, perceptual abnormalities, or cognitive impairments. Authors expressed the fact that using TMS to therapeutically enhance cognition (and facilitate rehabilitation) remains challenging.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/15165553
2004: Research with TMS has shown that the technique can help generate transitory “lesion”-like effects. In other words, a healthy participant’s brain can be stimulated with TMS to temporarily mimic the effects of a lesion. This can help researchers learn how lesions in certain areas of the brain are likely to influence behaviors and cognitive processes.
It also gives us a better understanding of specific areas within the brain responsible for certain elements of cognition. As an example, it is known that TMS administered to the visual processing center of the brain can impair visual detection abilities. Another example is administration of TMS to the left middle frontal gyrus results in decreased reaction time.
However, rather than generating a transient lesion-like effect, what if TMS could be used to enhance cognitive processes for an extended duration? Authors noted that there was preliminary evidence to suggest that TMS may enhance aspects of neurocognition. These enhancements may be more likely among those with psychiatric or neurological disorders, but may also be attained by individuals with normative mental health.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/15538312
2003: A 2003 study documented the effects of rapid-rate rTMS for enhancement of cognitive performance. Prior to this study, researchers noted that task performance improves when upper alpha wave frequencies are suppressed. The suppression of these frequencies can be accomplished when a large upper alpha power is administered in intervals prior to a cognitive task.
The administration of upper alpha intervals could be easily accomplished via rTMS. It was thought that the administration of individual alpha frequency (IAF) via rTMS would alter alpha desynchronization, thereby enhancing task performance abilities among participants. Researchers administered rTMS to the (Fz) mesial frontal and (P6) right parietal – sites of participant brains.
They evaluated the effects of IAF stimulation (rTMS) to a sham-TMS, making note of cognitive behavioral effects. Results indicated that rTMS at IAF + 1 Hz is capable of enhancing task performance (as a result of task-related alpha desynchronization). This study noted that strategic use of rTMS to manipulate alpha activity can enhance cognitive function.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/12653991
2001: A study published in 2001 noted that rTMS could be used to improve neural functionality among those who’ve endured brain damage. For the study, researchers focused on determining whether TMS could be used to help individuals suffering from brain damage-induced spatial neglect. They recruited healthy subjects and administered rTMS at 1 Hz for 10 minutes over either the right or left parietal cortex.
Results suggested that the opposite hemisphere (of the side stimulated) was impaired when stimuli were present in the opposite hemifield; this is similar to those with brain damage-induced spatial neglect. However, visual attention to ipsilateral targets was substantially enhanced by TMS. While this study has implications for those with brain damage, it also may demonstrate that enhancement of certain cognitive processes may come at the temporary expense of others.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/11528429/
Can TMS really enhance cognitive function?
Yes, there is evidence to suggest that certain TMS protocols are capable of enhancing cognitive function. The extent to which cognitive function is enhanced, as well as the duration of the enhancement is unclear. Many of the aforementioned studies have demonstrated the efficacy of TMS for enhancement of cognitive processes (and task performance) among healthy volunteers, as well as those with psychiatric disorders (e.g. major depression).
Some speculate that those with psychiatric and neurological disorders stand to attain more cognitive benefit from TMS than a healthy individual. However, there is emerging evidence to suggest that even healthy volunteers can derive significant cognitive enhancement from TMS. Although the mechanisms responsible for TMS-induced cognitive enhancement aren’t fully understood, the technique appears to work.
Note: It is important to note that improper usage of TMS could actually cause cognitive impairment. Therefore, it will be important for researchers to distinguish the protocols that are likely to provide enhancement from those that are likely to cause impairment.
Cognitive Processes to be Enhanced with TMS
There are a multitude of cognitive processes that could be enhanced with TMS. These include things like: cognitive flexibility, learning, memory, motor skills, perception, and visual performance. While it may be exciting to think that cognition can be enhanced, it is also exciting to think beyond the sole scope of cognition. Imagine if your communication skills, motivation, or self-discipline could be enhanced with TMS (or related technologies).
- Cognitive flexibility: Your ability to switch from thinking about one mental concept to that of another is referred to as “cognitive flexibility.” Cognitive flexibility also sometimes refers to an ability to simultaneously reflect upon multiple concepts or trains-of-thought. There is some evidence to suggest that TMS may be a viable intervention for increasing cognitive flexibility.
- Learning: Specific TMS protocols have been effective for enhancement of learning tasks. Stimulating a particular area on the prefrontal cortex can result in reduced learning time and superior consolidation of the learning process. Since TMS can also be used to interfere with learning, it is important to understand the protocols most effective for the particular type of learning task that an individual will perform.
- Memory: It is thought that learning and memorization of new material can be improved with TMS. Although the effect of TMS is transient, even a transient effect could provide significant benefit. Imagine if you were able to slash your learning time of new material in half following a TMS protocol. Even if the TMS effect lasted a few hours, the memories formed wouldn’t disappear after the effect wore off. It is thought that short-term (working) memory and long-term memory could be improved with TMS.
- Motor function: Those with motor deficits may be able to correct them (at least temporarily) with TMS. Motor function is often impaired among those with neurological disorders (e.g. Parkinson’s), but TMS may provide therapeutic benefit as an adjunct intervention. The key will be to determine whether the enhancement of motor skills following TMS can be maintained and for what duration.
- Perception: Some research suggests that TMS could enhance perceptual abilities. Perceptual enhancement may entail: vision, hearing, taste, touch, or smell. Individuals with sensory deficiencies may be able to reverse them (at least temporarily) via TMS to specific regions of the brain.
- Visual performance: TMS has been used to enhance visual performance tasks among those with neurological damage. It could be thought that visual performance could be manipulated and improved with TMS. This may be beneficial for those with suboptimal visual task performance and/or may be beneficial for individuals with jobs requiring heightened visual awareness (e.g. professional athletes).
Further research of TMS for cognitive enhancement is warranted
It is clear that further research of TMS for cognitive enhancement is warranted. Although research in normative, healthy individuals will likely get put on the backburner (due to the fact that this is a “medical treatment”), research among those with psychiatric and neurological disorders will continue to surface. It will be especially helpful to understand whether individuals with neurodegenerative diseases derive cognitive benefit from TMS.
- Healthy adults: Many individuals are intrigued by the potential of TMS to enhance cognition in healthy adults. It is necessary to conduct further research among adults with normative cognitive function (without psychiatric or neurological disorders). This research will help researchers distinguish whether healthy adults require different stimulation protocols than those with disorders. Further, it will help us understand the degree to which a healthy individual can derive cognitive benefit from TMS.
- Individual protocols: It is important to consider the potential of using “individualized” TMS protocols in the future. Not everyone shares the same pre-TMS brain activity or the same brain anatomy. It is therefore necessary to consider analyzing brains on an individual basis via neuroimaging and developing protocols to enhance cognition based off of individual brain activity. It is likely that “personalized” protocols will yield greater benefit than simply using the same protocol for every patient.
- Larger sample sizes: Sample sizes in most TMS studies are relatively small. Since the technique is primarily studied for the treatment of psychiatric conditions and neurological disorders, there are very few studies that specifically analyze its cognitive effects. It is hoped that future research is conducted with larger sample sizes to better understand whether the technique can effectively enhance cognition – especially among healthy adults.
- Neurological disorders: Preliminary evidence suggests that TMS can effectively enhance cognitive function among those with neurodegenerative diseases (dementia, Parkinson’s, MCI) and among individuals undergoing stroke rehabilitation. Further research is necessary to determine the ideal protocols for individuals with neurological disorders. Some speculate that TMS could replace certain medications and/or be used as an effective adjunct.
- Psychiatric disorders: Severe psychiatric disorders like major depression, anxiety, and schizophrenia are often associated with cognitive impairment. Treatment of these conditions seems to improve cognitive function, but often is insufficient for individuals to concentrate in demanding educational or workplace environments. TMS protocols may be effective as an adjunct treatment to enhance cognition among those with psychiatric disorders.
- Stimulation parameters: There are an array of parameters that have been discovered to effectively enhance cognitive function via TMS. However, some of these parameters differ from one another and the duration of enhancement may vary based on the parameters utilized. Researchers should attempt to understand the specific parameters most beneficial for enhancement of a cognitive process. In other words, stimulation site(s), frequencies, motor thresholds, number of sessions, time between pulses, etc. – should all be analyzed.
- Study designs: There is a need for improved study designs in nearly all TMS research. Study designs should be randomized, blinded, and sham-controlled. There are often difficulties creating a convincing “sham”-TMS and as a result, some study participants can tell when they’ve received the “sham.” Future research should attempt to develop a more convincing sham to bolster credibility of research.
- Types of TMS: There are various types of TMS that elicit different stimulatory effects. For example, deep-TMS is capable of targeting regions deeper beneath the cortex than standard TMS. It is unclear as to whether the enhancement of a specific cognitive function may be superior with deep-TMS, while the enhancement of another may be superior with standard rTMS. Deep TMS may stimulate regions involved in non-cognitive, but beneficial processes like motivation, whereas rTMS may be more effective for abstract thinking.
- Universal protocols: For the treatment of cognitive impairment associated with psychiatric and neurological conditions, it is beneficial to discover targeted, effective TMS protocols that can be used for cognitive enhancement. These universally effective protocols aren’t yet well-established. Furthermore, it could be speculated that a certain set of stimulatory parameters could be discovered that provide a cognitive boost to anyone, regardless of neurological health. It will take significant more testing and research to understand whether such universally effective “cognitive enhancing” TMS protocols exist.
Ethical concerns associated with using TMS for cognitive enhancement?
There are likely going to be individuals who are ethically opposed to using technology to enhance human performance, especially among those with normative mental health. Imagine if someone with a high IQ was able to ramp up their intelligence even more with TMS… would this be fair? Some ethicists would argue that it wouldn’t be fair for a variety of reasons.
I think that everyone (regardless of intelligence) should have the right to use a technology to enhance their performance if it is safe. Making the smartest people “smarter” and more efficient will benefit everyone and speed up the pace of advancement. Even if someone like myself gets left in the dust, I’d rather have a smarter, more educated society because it benefits everyone.
It is still unclear as to whether “cognitively advanced” individuals will derive as much enhancement from TMS protocols as those who are of normal intelligence and/or suffering from a psychiatric disorder. For example, certain protocols appear to help individuals with depression and enhance their cognition, but actually impair cognition among healthy people. Assuming everyone stands to benefit significantly from TMS-induced cognitive enhancement, ethicists will come out of the woodwork.
They may attempt to make “cutoffs,” controlling who should be allowed to receive the TMS for enhancement and who shouldn’t. Even if they have a criteria for who is “allowed” to receive TMS and who “isn’t allowed’ to receive it, there will be an inevitable grey area. Some will argue that a slightly disordered individual who reaps significant cognitive benefit from TMS is unfair if a non-disordered individual is unable to use the technology.
There are also financial inequality concerns that some individuals may have – the rich may have access to the technology whereas the poor may not. That said, the price of technology continues to plummet and it is likely that it wouldn’t take long for such technology to be universally available. I don’t have any ethical objections to using any safe technology (including TMS) for cognitive enhancement because it simply improves everyone’s functioning and humanity’s overall potential.
Would you use TMS for cognitive enhancement?
If you could harness TMS and utilize electromagnetic induction to strategically enhance certain cognitive processes, would you do it? Even if you knew the enhancement of these cognitive processes would come at expense to others? Early research seems to suggest that TMS is a viable option for cognitive enhancement, but it is far from being approved by the FDA as a cognitive enhancer – especially among those without any psychiatric or neurological disorder.
Be sure to leave a comment below mentioning whether you would use TMS to bolster your cognitive horsepower if it was available. Do you have any ethical objections for someone using TMS to enhance their cognition? In the future (possibly the far future), I speculate that an improved device (non TMS) will be sold to consumers that allows them to sustainably enhance their cognitive function for a period of time.
For example, a person needs to perform calculations, they’d hook up a TMS-like device to some circuitry and apply stimulation for improved calculation abilities. Another person may need to socialize, so they could stimulate neural pathways needed for optimal communication abilities. If such a device were available, it would help guide the brain in an optimal direction for a given task and increase its operating efficiency.