Online research in philosophy

The advent of functional brain imaging has revolutionized the ability to understand the biological mechanisms underlying decision-making. Although it has been amply demonstrated that assumptions of rationality often break down in experimental games, there has not been an overarching theory of why this happens. I describe recent advances in functional brain imaging and suggest a framework for considering the function of the human reward system as a discrete agent.

Brain images are used both as scientific evidence and to illustrate the results of neuroimaging experiments. These images are apt to be viewed as photographs of brain activity, and in so viewing them people are prone to assume that they share the evidential characteristics of photographs. Photographs are epistemically compelling, and have a number of characteristics that underlie what I call their inferential proximity. Here I explore the aptness of the photography analogy, and argue that although neuroimaging does bear important similarities to photography, the details of the generation and analysis of neuroimages significantly complicate the relation of the image to the data. Neuroimages are not inferentially proximate, but their seeming so increases the potential for misinterpretation. This suggests caution in appealing to such images in the public domain.

While philosophers have, for centuries, pondered upon the relation between mind and brain, neuroscientists have only recently been able to explore the connection analytically — to peer inside the black box. This ability stems from recent advances in technology and emerging neuroimaging modalities. It is now possible not only to produce remarkably detailed images of the brain’s structure (i.e. anatomical imaging) but also to capture images of the physiology associated with mental processes (i.e. functional imaging). We are able to see how specific regions of the brain ‘light up’ when activities such as reading this book are performed, and how our neurons and their elaborate cast of supporting cells organize and coordinate their tasks. As demonstrated in the other chapters of this book, the mapping of the human mind (mostly by measuring regional changes in blood flow, initially by positron emission tomography (PET) and recently by functional magnetic resonance imaging or (fMRI)) has provided insight into the functional neuroanatomy of neuropsychiatric diseases. Amazingly, the idea that regional cerebral blood flow (rCBF) is related intimately to brain function goes back more than a century. As is often the case in science, this idea was initially the result of unexpected observations. The Italian physiologist Angelo Mosso first expressed the idea while studying pulsations of the living human brain that keep pace with the heartbeat (Mosso, 1881). These brain pulsations can be observed on the surface of the fontanelles in newborn children. Mosso believed that they reflected blood flow to the brain. He observed similar pulsations in an adult with a post-traumatic skull defect over the frontal lobes. While studying this subject, a peasant named Bertino, Mosso observed a sudden increase in the magnitude of the ‘brain’s heart-beats’ when the church bells signalled 12 o’clock, the time for a required prayer. The changes in brain pulsations occurred independently of any change in pulsations in the forearm..

Different cognitive functions recruit a number of different, often overlapping, areas of the brain. Theories in cognitive and computational neuroscience are beginning to take this kind of functional integration into account. The contributions to this special issue consider what functional integration tells us about various aspects of the mind such as perception, language, volition, agency, and reward. Here, I consider how and why functional integration may matter for the mind; I discuss a general theoretical framework, based on generative models, that may unify many of the debates surrounding functional integration and the mind; and I briefly introduce each of the contributions.

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.

Anatomical studies propose that the primate auditory cortex contains more fields than have actually been functionally confirmed or described. Spatially resolved functional magnetic resonance imaging (fMRI) with carefully designed acoustical stimulation could be ideally suited to extend our understanding of the processing within these fields. However, after numerous experiments in humans, many auditory fields remain poorly characterized. Imaging the macaque monkey is of particular interest as these species have a richer set of anatomical and neurophysiological data to clarify the source of the imaged activity. We functionally mapped the auditory cortex of behaving and of anesthetized macaque monkeys with high resolution fMRI. By optimizing our imaging and stimulation procedures, we obtained robust activity throughout auditory cortex using tonal and band-passed noise sounds. Then, by varying the frequency content of the sounds, spatially specific activity patterns were observed over this region. As a result, the activity patterns could be assigned to many auditory cortical fields, including those whose functional properties were previously undescribed. The results provide an extensive functional tessellation of the macaque auditory cortex and suggest that 11 fields contain neurons tuned for the frequency of sounds. This study provides functional support for a model where three fields in primary auditory cortex are surrounded by eight neighboring ‘‘belt’’ fields in non-primary auditory cortex. The findings can now guide neurophysiological recordings in the monkey to expand our understanding of the processing within these fields. Additionally, this work will improve fMRI investigations of the human auditory cortex.

Since its development about 15 years ago, functional magnetic resonance imaging (fMRI) has become the leading research tool for mapping brain activity. The technique works by detecting the levels of oxygen in the blood, point by point, throughout the brain. In other words, it relies on a surrogate signal, resulting from changes in oxygenation, blood volume and flow, and does not directly measure neural activity. Although a relationship between changes in brain activity and blood flow has long been speculated, indirectly examined and suggested and surely anticipated and expected, the neural basis of the fMRI signal was only recently demonstrated directly in experiments using combined imaging and intracortical recordings. In the present paper, we discuss the results obtained from such combined experiments. We also discuss our current knowledge of the extracellularly measured signals of the neural processes that they represent and of the structural and functional neurovascular coupling, which links such processes with the hemodynamic changes that offer the surrogate signal that we use to map brain activity. We conclude by considering applications of invasive MRI, including injections of paramagnetic tracers for the study of connectivity in the living animal and simultaneous imaging and electrical microstimulation. D 2004 Elsevier Inc. All rights reserved.

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.

Abstract   Producing and interpreting functional brain data is part of the negotiation we imagine our brain. To take a closer look at the idea of brain imaging as a form of visual knowledge, it is necessary to put the research of today into a historical context. In my article I will point to a specific approach of functional imaging which depends on historical shifts entangled with the visual aspect of producing pictures of the brain. I will bring out the interaction of issues like techniques, models and historical assumptions of the brain and link them with the way the brain images are presented. The aesthetic dimensions (Rancière) in the pictures are also questions of ethics and normativity. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s12152-011-9139-z Authors Hannah Fitsch, Technische Universität Berlin, Berlin, Germany Journal Neuroethics Online ISSN 1874-5504 Print ISSN 1874-5490.

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.