Tag Archives: fmri

The Inner Life of Vegetative Patients and Why It Matters

MRI

Here’s the latest draft of my paper on covert consciousness in the vegetative state, which is still very much a work-in-progress. If you compare it to the earlier draft I posted, you can see I am taking the paper in a more bioethical direction, which is a whole new ballgame for me. Comments welcome.

Abstract: Adrian Owen and colleagues (2006 et al.) report using functional neuroimaging to detect residual levels of conscious awareness in patients diagnosed with vegetative state syndrome. These studies have generated immense scientific and public interest largely due to the putative moral significance of consciousness. These findings raise vexing philosophical and ethical questions about the nature of consciousness and its moral significance. My goal in this paper is to critically examine these findings and evaluate their significance from a clinical-ethical perspective. The general lesson is that determining the moral significance of consciousness is complex and multifaceted.

Link to PDF: Williams 4-24-14-InnerLifeofVegetativePatients

5 Comments

Filed under Consciousness, Moral Philosophy, Philosophy, Psychology

Draft of Latest Paper – Awake But Not Aware: Probing For Consciousness in Unresponsive Patients

patient

Ok everyone, here’s a paper I’m really excited about. The topic is so “me” — the first project I’ve wholeheartedly thrown myself into since since I came to Wash U. I can see myself wanting to write a dissertation or book on the topic so this paper will likely serve as the basis for a prospectus in the near future. The issue I’m dealing with in the paper is situated at the intersection of a variety of fields ranging from philosophy of mind, philosophy of science, cutting edge neuroscience, clinical neurology and biomedical ethics. I could conceivably “sell” the project to a variety of people. The project is obviously at an early stage of development and the paper is drafty but I have the rest of the semester to work on this so I’m open to any comments, criticisms, or questions. Thanks!

For PDF of paper, click here –> Williams-AwakeButNotAware-Draft-3-03-14

Here’s a tentative abstract:

The standard approach in clinical neurology is to diagnose disorders of consciousness (DOC) on the basis of operationally defined behaviors. Critics of the standard approach argue that it relies on a flawed behaviorist epistemology that methodologically rules out the possibility of covert consciousness existing independently of any observable behavior or overt report. Furthermore, critics point to developments in neuroimaging that use fMRI to “actively probe” for consciousness in unresponsive patients using mental imagery tasks (Owen et al. 2006). Critics argue these studies showcase the limitations of the standard approach. The goal of this paper is to defend the standard approach against these objections. My defense comes in two parts: negative and positive. Negatively, I argue that these new “active probe” techniques are inconclusive as demonstrations of consciousness. Positively, I reinterpret these active probes in behavioral terms by arguing they are instances of “brain behaviors”, and thus not counterexamples to the standard approach.

Leave a comment

Filed under Academia, Consciousness, Philosophy, Philosophy of science, Psychology

Strong and Weak Modularity

When evaluating the truth of the modularity thesis about the brain, it’s important to distinguish between two forms modularity can take: a strong form and a weak form. The strong form is the view that the brain is organized along the lines of a swiss army knife, with hundreds or thousands of modules like the “mate selection module”, “food detection module”, or “cheater detection module”, with each module running a dedicated task. The weak form is simply the thesis that you can turn off or take out some parts of the brain without shutting down the whole system. For example, weak modularity is the idea that if you removed the auditory cortex your visual system would not completely crash and vice-versa.

The strong form is usually committed to things like “information encapsulation”. But there are two forms encapsulation might take: strong and weak. The stronger form says that any given module runs completely independently from other modules and when it is running its processes it uses its own internal knowledge to process it. This is supposed to be why the Müller-Lyer can’t be turned off even if you know it’s an illusion. The weak form views encapsulation a little different. On the weak view, each module is “talking” to a lot of other modules, and the idea is that when you have different modules talking to each other, new functions arise. The weak form thus sees modules built out of other modules, like a nested hierarchy. On this view, “encapsulation” has the wrong metaphorical connotations. Encapsulated seems to mean something like “isolated”. But on the weak interpretation, modules are not isolated at all; they are situated in a complex causal network of different modules. Moreover, the stronger form usually says that each module only really runs one process e.g. the cheater detection module only detects cheating. On the weak view however, it’s theoretically possible that a module could do more than one thing.

So when we look at task-based fMRI data using subtraction logic and are tempted to talk about a “theory of mind module” at one particular loci, we need to think about both the weak and strong forms of modularity and the weak and strong forms of information encapsulation. For the weak view of modularity, the theory of mind module is only modular because you could lesion it without shutting down the rest of the brain. And on the weak view of encapsulation, it’s more likely that theory of mind capacity stems from the powers of a distributed network of modules with the one particular loci that is “subtracted” out also being capable of helping out in other things beside theory of mind. The strong view of modularity and encapsulation would say the particular loci that is “most active” is the place where theory of mind happens. Michael Anderson has recently done meta-analyses of fMRI data and concluded that what’s going on often is cases where cortical areas are redeployed to perform new tasks, so the idea that any given brain loci does just one thing is mistaken. Since the brain constantly recruits old circuits to do new tasks, the strong form of encapsulation is going to be wrong: each loci can participate in different tasks in a slightly different way.

Leave a comment

Filed under Philosophy, Psychology