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- Colin Klein, Significance, Evidence, and the Uncomfortable Science of fMRI.Functional magnetic resonance imaging (or fMRI)1 is widely used to support hypotheses about brain function. Many find the images produced from fMRI data to be especially compelling evidence for scientific hypotheses [McCabe and Castel, 2008]. There are many problems with all of this; I want to start with two of them, and argue that they get us closer to an under-appreciated worry about many imaging experiments.No categories
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was to test the role of both early and higher visual areas in the integration of local features into global shapes. To this end, we conducted functional magnetic resonance imaging (fMRI) studies. Although fMRI lacks the high spatial resolution of intracortical recordings, it allows simultaneous collection of responses to the same stimulus set from multiple visual areas that is not possible with standard recording techniques. We performed these studies in monkeys, where much is known about the properties of neurons in different visual areas (Hubel and Wiesel, 1968; Felleman and Van Essen, 1991; Van The integration of local image features into global Essen et al., 1992), and in humans, where recent fMRI..
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Good research requires, among other virtues,(i) methods that yield stable experimentalobservations without arbitrary (post hoc)assumptions, (ii) logical interpretations ofthe sources of observations, and (iii) soundinferences to general causal mechanismsexplaining experimental results by placing themin larger explanatory contexts. In TheNew Phrenology , William Uttal examines theresearch tradition of localization, and findsit deficient in all three virtues, whetherbased on lesion studies or on new technologiesfor functional brain imaging. In this paper Iconsider just the arguments concerning brainimaging, especially functional MagneticResonance Imaging. I think that Uttal is tooharsh in his methodological critique, butcorrect in his assessment of the conceptuallimitations of localist evidence. I proposeinstead a data-driven test for assessingrelative modularity in brain images, and showits use in a secondary analysis of fMRI datafrom the National fMRI Data Center(www.fmridc.org). Although the analysis is alimited pilot study, it offers additionalempirical challenge to localism.
fMRI is a tool to study brain function noninvasively that can reliably identify sites of neural involvement for a given task. However, to what extent can fMRI signals be related to measures obtained in electrophysiology? Can the blood-oxygen-level-dependent signal be interpreted as spatially pooled spiking activity? Here we combine knowledge from neurovascular coupling, functional imaging and neurophysiology to discuss whether fMRI has succeeded in demonstrating one of the most established functional properties in the visual brain, namely directional selectivity in the motion-processing region V5/ MT+. We also discuss differences of fMRI and electrophysiology in their sensitivity to distinct physiological processes. We conclude that fMRI constitutes a complement, not a poor-resolution substitute, to invasive techniques, and that it deserves interpretations that acknowledge its stand as a separate signal.
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Cognitive neuroscientists use functional magnetic resonance imaging (fMRI) to measure properties of a participant’s brain during a cognitive task. These imaging results are transformed into compelling pictures of brain activity using statistical models. I will argue that, for a broad class of experiments, neuroimaging experts have a tendency to over‐interpret the functional significance of their data. This over‐interpretation appears to follow from contentious theoretical assumptions about the mind‐brain connection, and from a propensity to conflate the anatomical location of a statistically‐significant correlation with knowledge of the mechanistic functioning at that location.
In this paper, I argue that companies who use functional Magnetic Resonance Imaging (fMRI) scans for lie detection encounter the same basic ethical stumbling blocks as commercial companies that market traditional polygraphs. Markets in traditional voluntary polygraphs are common and fail to elicit much uproar among ethicists. Thus, for consistency, if markets in polygraphs are ethically unproblematic, markets using fMRIs for lie detection are equally as acceptable. Furthermore, while I acknowledge two substantial differences between the ethical concerns involving polygraphs and fMRI lie detection, I argue that these concerns can be overcome and do not lead to the conclusion that markets in fMRI lie detection are ethically dubious. It is my conclusion that voluntary markets in fMRI lie detection can be justified by consumer autonomy and should be allowed to persist.
Functional neuroimaging (NI) technologies like Positron Emission Tomography and functional Magnetic Resonance Imaging (fMRI) have revolutionized neuroscience, and provide crucial tools to link cognitive psychology and traditional neuroscientific models. A growing discipline of 'neurophilosophy' brings fMRI evidence to bear on traditional philosophical issues such as weakness of will, moral psychology, rational choice, social interaction, free will, and consciousness. NI has also attracted critical attention from psychologists and from philosophers of science. I review debates over the evidential status of fMRI, including the differences between brain scans and ordinary images, the legitimacy of forward inference and reverse inference, and deductive versus probabilistic accounts of NI evidence. I conclude with a discussion of fMRI as exploratory rather than confirmatory evidence, linking this debate to the growing literature on cognitive ontology.
fMRI promises to uncover the functional structure of the brain. I argue, however, that pictures of ‘brain activity' associated with fMRI experiments are poor evidence for functional claims. These neuroimages present the results of null hypothesis significance tests performed on fMRI data. Significance tests alone cannot provide evidence about the functional structure of causally dense systems, including the brain. Instead, neuroimages should be seen as indicating regions where further data analysis is warranted. This additional analysis rarely involves simple significance testing, and so justified skepticism about neuroimages does not provide reason for skepticism about fMRI more generally.
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