Consciousness

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Measuring Consciousness using fMRI

Functional magnetic resonance imaging is a measure of activity in the brain using an MRI machine. MRI machines generate a magnetic field that can scan a brain for electrical activity. In this way, researchers are not able to know what you are thinking but where you are thinking and associate certain areas with certain purposes. For example, the act of seeing and vision is associated with the back of the brain.

When is comes to measuring consciousness, fMRI scanners are incredibly useful too. They surpass the traditional methods of simply observing a patient’s behaviour to determine consciousness because they display activity and surely activity relates to consciousness. Would that it actually were so simple.

In reality, the concept of consciousness remains elusive and we cannot simply scan a brain to discern whether a person has consciousness. What we can do, however, is talk to an individual during an fMRI scan and observe the activity produced. Such techniques allow us to distinguish between those in a vegetative state and those with locked-in syndrome (the latter involving similar behavioural symptoms to a vegetative state but complete retention of consciousness). As many as 4 out of 23 patients in a recent study were found to be not vegetative (as previously considered) when placed in an fMRI scanner. While smaller than chance, most certainly, this figure suggests that as many as one in six patients considered vegetative could have been mis-diagnosed. Indeed 3 of the previously mentioned 4 patients could conjure up mental imagery (e.g. playing tennis) so well as to be mapped on their brain activity scans meaning they weren’t simply aware of their surroundings but had retention of mental abilities. One of these three patients then went on to answer yes-no questions using this technique.

While fascinating in itself, the work done by Monti et al. (2009;2010) did not directly indicate that only these four individuals were conscious. By their own admittance, it would be impossible to determine whether the others were completely unconscious or simply unable to hear and so unable to use the auditory information they were given. The issue is further compounded by the fact a conscious individual would have intact sleep cycles, meaning they could easily sleep straight through an fMRI test and appear to have no activity. Hence, even in something so quantitative, there is a subjective element to consciousness.

With such uncertainty the future of fMRI measures of consciousness may lie in tactile stimulation (touch) and visual stimuli as secondary measures of consciousness in the event of a negative auditory result. Until then, clinicians, carers and relatives are left, as Functional magnetic resonance imaging is a measure of activity in the brain using an MRI machine. MRI machines generate a magnetic field that can scan a brain for electrical activity. In this way, researchers are not able to know what you are thinking but where you are thinking and associate certain areas with certain purposes. For example, the act of seeing and vision is associated with the back of the brain.

When is comes to measuring consciousness, fMRI scanners are incredibly useful too. They surpass the traditional methods of simply observing a patient’s behaviour to determine consciousness because they display activity and surely activity relates to consciousness. Would that it actually were so simple.

In reality, the concept of consciousness remains elusive and we cannot simply scan a brain to discern whether a person has consciousness. What we can do, however, is talk to an individual during an fMRI scan and observe the activity produced. Such techniques allow us to distinguish between those in a vegetative state and those with locked-in syndrome (the latter involving similar behavioural symptoms to a vegetative state but complete retention of consciousness). As many as 4 out of 23 patients in a recent study were found to be not vegetative (as previously considered) when placed in an fMRI scanner. While smaller than chance, most certainly, this figure suggests that as many as one in six patients considered vegetative could have been mis-diagnosed. Indeed 3 of the previously mentioned 4 patients could conjure up mental imagery (e.g. playing tennis) so well as to be mapped on their brain activity scans meaning they weren’t simply aware of their surroundings but had retention of mental abilities. One of these three patients then went on to answer yes-no questions using this technique.

While fascinating in itself, the work done by Monti et al. (2009;2010) did not directly indicate that only these four individuals were conscious. By their own admittance, it would be impossible to determine whether the others were completely unconscious or simply unable to hear and so unable to use the auditory information they were given. The issue is further compounded by the fact a conscious individual would have intact sleep cycles, meaning they could easily sleep straight through an fMRI test and appear to have no activity. Hence, even in something so quantitative, there is a subjective element to consciousness.

With such uncertainty the future of fMRI measures of consciousness may lie in tactile stimulation (touch) and visual stimuli as secondary measures of consciousness in the event of a negative auditory result. Until then, clinicians, carers and relatives are left, as Schwarzbauer and Schafer say “confronted with a vast grey-zone ranging from cases lose to brain death at one end of the spectrum and cases close to the threshold of perception and awareness at the other end.” New techniques such as functional connectivity MRI (fcMRI) are being developed as a more accurate measure of activity in functional networks associated with consciousness.

From a legal perspective, developments in fMRI techniques also provide the potential for doctor-patient dialogue; something never before experience with unconscious patients. Once a yes-no code is established, permission and decisions can be communicated from patient to doctor, as well as non visible symptoms. These yes-no statements provided when a patient is unconscious have important influence when it comes to things such as ‘do not resuscitate’ orders given by the patient before the onset of the altered state. In England and Wales specifically, the Mental Capacity Act of 2005 permits communication other than speech as a mode of revoke the DNR order previously given as “a change of mind is recognised as a revocation of a prior oral or written instruction, even if it does not meet the requirements of a legal statement.”
and Schafer say “confronted with a vast grey-zone ranging from cases lose to brain death at one end of the spectrum and cases close to the threshold of perception and awareness at the other end.” New techniques such as functional connectivity MRI (fcMRI) are being developed as a more accurate measure of activity in functional networks associated with consciousness.

From a legal perspective, developments in fMRI techniques also provide the potential for doctor-patient dialogue; something never before experience with unconscious patients. Once a yes-no code is established, permission and decisions can be communicated from patient to doctor, as well as non visible symptoms. These yes-no statements provided when a patient is unconscious have important influence when it comes to things such as ‘do not resuscitate’ orders given by the patient before the onset of the altered state. In England and Wales specifically, the Mental Capacity Act of 2005 permits communication other than speech as a mode of revoke the DNR order previously given as “a change of mind is recognised as a revocation of a prior oral or written instruction, even if it does not meet the requirements of a legal statement.”


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