Tuesday, April 8, 2014

Can free will be modulated through electrical stimulation?

The will to persevere when many of life’s challenges are thrown at us is an ability that comes more naturally for some than for others. Additionally, even the most determined among us have days and times when moving forward through a challenging task just proves too difficult. The subjective nature of this experience can make it difficult to study, but recently researchers from Stanford University published a case study where electrical brain stimulation (EBS) to the anterior midcingulate cortex (aMCC) left two patients with the feeling that a challenge was approaching, but also that they could overcome it [1]. For the most recent journal club of the semester, Neuroscience graduate student and AJOB Neuroscience editorial intern Ryan Purcell led a discussion on the experimental procedure to stimulate what is referred to as the “the will to persevere” and the effect this technology may have if it were to become more mainstream in society.

"The location of the electrodes in P1 and P2 overlaid onto the standard emotional salience network derived from a group of normal human subjects." Parvizi et al.

It has long been known that the anterior cingulate cortex (ACC) and its midcingulate region (aMCC) are involved in emotions that rely on cognitive control, and recent research has shown that this brain network is possibly involved in complex emotions such as motivation and endurance [2,3]. In the case study discussed during journal club though, researchers went beyond an animal study and recorded a first-hand account of two patients becoming determined and motivated to overcome what they perceived as an oncoming challenge during EBS to the aMCC. The aMCC, located deep within the brain, is not typically implanted with electrodes for clinical reasons, but researchers were attempting to discover the origin of seizure activity in two patients with epilepsy by implanting intracranial electrodes in four different deep brain regions. Electrical currents at each of these regions were delivered and then based on patient feedback and physiological reports, researchers could localize the epileptic activity. It was determined that the patients were suffering from medial temporal epilepsy, but when electrical stimulation occurred at the aMCC, while no signs of seizures were observed, both patients did report similar and unique emotional states, along with specific physical symptoms. Patients physically experienced what was described as “shakiness,” hot flashes, and an increase in heart rate, but interestingly also psychologically felt a sense of foreboding regarding a challenge and the confidence that the challenge could be overcome. As seen in this supplemental video, patient 1 describes the experience as driving “towards a storm that’s on the other side, maybe a couple of miles away, and you've got to get across that hill.” Although this seems like a situation that would cause worry and anxiety, the same patient reported that the feeling was not really negative, but instead “it was more of a positive thing like…push harder, push harder, push harder to try and get through this.” These patient accounts suggest that researchers had tapped into the part of the brain responsible for motivation, endurance, and the will to persevere, and in doing so were able to elicit these feelings on command - far removed from any situation similar to stressful driving.

Researchers also realized that by stimulating the aMCC, the behavioral and emotional changes caused by EBS could potentially be due to functional changes that take place within a vast neuronal network connected to the aMCC. Using fMRI and functional connectivity analysis, researchers observed that EBS in the aMCC region of interest led to the activation of a network previously characterized as the emotional salience or cingulo-opercular network [4]. This suggests that the motivation, endurance, or the lack of these two emotions are most likely not alone regulated by a single brain region, the aMCC, but instead a complex, distributed network.

This paper presents the exciting and interesting idea that we could regulate motivation with stimulation to the brain, but really this is just a small case study with two patients. These findings may have been an unexpected result from trying to find the source of epilepsy, and may only occur in this experimental setting, perhaps even only in patients who have a history of epilepsy. The paper reads as if the researcher asking the questions of the patients was the same researcher conducting the stimulation trials, and as a result many of the questions are very biased and leading. After patient 1 has vividly compared his experience to driving in a storm, the researcher attempts to ask patient 2 about driving as well. To which patient 2 responds with laughter “I don’t get to drive.”

This is an interesting observation, but would need to be replicated on a larger scale with blind research practices put into place. However, since the aMCC is located deep within the brain and typically electrodes are not inserted for clinical reasons, it may prove difficult to conduct invasive procedures without a clinical agenda. In this case study, these patients were already unique in that they may have been very determined individuals even without external stimulation since they were undergoing invasive brain surgery for epilepsy most likely as a last resort. Having the power to increase motivation and/or determination could be used in a clinical setting for depression or chronic pain, and while it is only speculation regarding the personality traits of these two patients, a study that is open to participants without any diagnosed neurological disorders could provide more baseline activity for modulating the aMCC and its neuronal network. For this large study to take place though and to find interested participants, most likely the technology would need to advance with a noninvasive procedure.

While this type of technology would have obvious clinical benefits for treating depression and perhaps one day the ability to self-regulate our motivations at home, having the power to externally regulate free will begs certain questions. Should anyone be denied the chance to become a more productive, motivated version of themselves? Or, if this type of technology were considered acceptable, should anyone be forced to become a more determined, motivated citizen who does not experience weakness of will? If advances in neuroscience continue to address the questions of whether free will even exists at all, and then if we ever have the power to impose a standard of willpower that everyone should meet, this would have important implications for our legal and justice system. Two common theories for justifying punishment include the utilitarianism and the retributivism theory [5]. Simply put, utilitarianism is based on the idea that punishment is justified because it produces a situation in which the balance of good and evil (or happiness and unhappiness) is maximized [6]. Punishment helps to reduce crimes, which promotes a society where good prevails over evil. For example, punishment in the form of imprisonment can lead to the reduction of crime because the idea of prison can deter criminals and criminals are removed from society. The retributivism theory relies more on the idea of a social consensus on what is deemed a moral wrongdoing and criminals who commit crimes deserve to be punished [7]. If we had the power to control weakness of will and modulate willpower, this could be very powerful when applied to crimes that are associated with a weakness of will, perhaps those that involve illicit drugs, alcohol, or even the more heinous pedophilia, as specifically discussed in this previous blog post. However, then the justification of additional punishment according to the utilitarian viewpoint would be less valid, since the stimulation alone would potentially reduce crime. In this situation, a criminal would be giving up some level of free will in the name of societal benefits, so one could argue that electrical stimulation could be considered similar to jail time, a punishment that removes freedom and the ability to make many choices from perpetrators’ lifestyles. In this sense, additional punishment according to the retributivism theory would also be less valid since the electrical stimulation would be punishment enough. Finally, there is an additional possibility that is being explored by neuroscientists like David Eagleman who believe that our retributivist justice system (resulting in an overcrowded prison system) should be revised to one focused on rehabilitation, or rather neuro-rehabilitation [8, 9, 10]. Even in the name of rehabilitation though, does such a crime exist that justifies the punishment of nonconsensual direct manipulation of neuronal networks? Having the strength and the will to persevere is most likely a characteristic that we all want all the time, but is choosing not to persevere still a choice that we are always entitled to make, regardless of the context of the choice?


References:

1) Parvizi, J. et al. (2013). The Will to Persevere Induced by Electrical Stimulation of the Human Cingulate Gyrus. Neuron 80, 1359.
2) Rudebeck, P.E. et al. (2006). Separate neural pathways process different decision costs. Nat. Neurosci. 9, 1161.
3) Shackman, A.J. et al. (2011). The integration of negative affect, pain and cognitive control in the cingulate cortex. Nat. Rev. Neurosci. 12, 154.
4) Seeley, W.W. et al. (2007). Dissociable intrinsic connectivity networks for salience processing and executive control. J Neurosci. 27, 2349.
5) Greene, J.; Cohen, J. (2004). For the law, neuroscience changes nothing and everything. Phil. Trans. R. Soc. Lond. B 359, 1775.
6) Bernstein, R.F. (1979). Legal Utilitarianism. Ethics 89, 127.
7) Scheid, D.E. (1983). Kant's Retributivism. Ethics 93, 262.
8) Eagleman, D.The Brain on Trial. (2011). The Atlantic. Retrieved on April 7, 2014 from http://www.theatlantic.com/magazine/archive/2011/07/the-brain-on-trial/308520/.
9) A novel addiction therapy: The real-time fMRI. Initiative on Neuroscience and Law. Retrieved on April 7, 2014 from http://www.neulaw.org/research/real-time-fmri. 
10) Rommelfanger, K. (2011). Neuro-rehabilitation: A vision for a new justice system. The Neuroethics Blog. Retrieved on April 7, 2014, fromhttp://www.theneuroethicsblog.com/2011/10/neuro-rehabilitation-vision-for-new.html

Want to cite this post?

Strong, K. (2014). Can free will be modulated through electrical stimulation? The Neuroethics Blog. Retrieved on , from http://www.theneuroethicsblog.com/2014/04/can-free-will-be-modulated-through_8.html

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