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. (shrink)
The philosophical tradition of phenomenology, with its focus on human bodily perception, can be used to explore the ways scientific instrumentation shapes a user’s experience. Building on Don Ihde’s account of technological embodiment, I develop a framework of concepts for articulating the experience of image interpretation in science. These concepts can be of practical value to the analysis of scientific debates over image interpretation for the ways they draw out the relationships between the image-making processes and the rival scientific explanations (...) of image content. As a guiding example, I explore a contemporary debate over images of the surface of Mars which reveal a landmass that resembles river delta formations on Earth, and which thus has important implications for the history of Martian climate and water flow. The phenomenological framework I develop can be used to help evaluate the different interpretations on offer for these images, and to analyze the roles in this discussion played by spacecraft equipped with cameras and laser and thermal imaging devices. (shrink)
A unifying theory of general anesthetic-induced unconsciousness must explain the common mechanism through which various anesthetic agents produce unconsciousness. Functional-brain-imaging data obtained from 11 volunteers during general anesthesia showed specific suppression of regional thalamic and midbrain reticular formation activity across two different commonly used volatile agents. These findings are discussed in relation to findings from sleep neurophysiology and the implications of this work for consciousness research. It is hypothesized that the essential common neurophysiologic mechanism underlying anesthetic-induced unconsciousness is, as (...) with sleep-induced unconsciousness, a hyperpolarization block of thalamocortical neurons. A model of anesthetic-induced unconsciousness is introduced to explain how the plethora of effects anesthetics have on cellular functioning ultimately all converge on a single neuroanatomic/neurophysiologic system, thus providing for a unitary physiologic theory of narcosis related to consciousness. (shrink)
I will argue that the fairly common assumption that brain imaging may compromise people’s privacy in an undesirable way only if moral crimes are committed is false. Sometimes persons’ privacy is compromised because of failures of privacy. A normal emotional reaction to failures of privacy is embarrassment and shame, not moral resentment like in the cases of violations of right to privacy. I will claim that if (1) neuroimaging will provide all kinds of information about persons’ inner life and (...) not only information that is intentionally searched for, and (2) there will be more and more application fields of fMRI and more and more people whose brains will be scanned (without any coercion), then, in the future, shame may be an unfortunately common feeling in our culture. This is because failures of privacy may dramatically increase. A person may feel shame strongly and long, especially if his failure is witnessed by people who he considers relatively important, but less than perfectly trustworthy. (shrink)
The goal of this study was to evaluate affective changes induced during mental imaging of instinctual action patterns. Subjects were first trained to simulate the bodily rhythms of laughter and crying and were then trained to image these processes without any movement. The mere imagination of the motor imagery of laughter and crying were sufficient to significantly facilitate happy and sad mood ratings as monitored by subjective self-report. In contrast, no changes in mood were reported while imaging the (...) affectively neutral task of walking. The work suggests that motor imagery is sufficient to modify emotional feelings, suggesting the feasibility of this method for brain imaging of emotional processes. (shrink)
Images, ranging from visualizations of the nanoscale to future visions, abound within and beyond the world of nanotechnology. Rather than the contrast between imaging , i.e. creating images that are understood as offering a view on what is out there, and imagining , i.e. creating images offering impressions of how the nanoscale could look like and images presenting visions of worlds that might be realized, it is the entanglement between imaging and imagining which is the key to understanding (...) what images do. Three main arenas of entanglement of imag(in)ing and the tensions involved are discussed: production practices and use of visualizations of the nanoscale; imag(in)ing the future and the present; and entanglements of nanoscience and art. In these three arenas one sees struggles about which images might stand for nanotechnology, but also some stabilization of the entanglement of imag(in)ing, for example in established rules in the practices of visualizing the nanoscale. Three images have become iconic, through the combination of their wide reception and further circulation. All three, the IBM logo, the Foresight Institute’s Nanogear image, and the so-called Nanolouse, depict actual or imagined technoscientific objects and are thus seen as representing technoscientific achievements – while marking out territory. (shrink)
Deception is an all-too-common human activity, one that succeeds because we cannot always detect it in others. It complicates all sorts of human decision-making, including attributing guilt for criminal offenses. The law relies on human fact-finders to determine whether criminal defendants claiming innocence, as well as witnesses testifying about a case, are telling the truth. But the fallibility of human lie detection has fueled the search for a more accurate replacement. Scientists have developed new approaches to lie detection that use (...) a brain scanning technique called functional magnetic resonance imaging (fMRI) to evaluate whether someone is lying. In experimental settings, researchers have found .. (shrink)
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.. (shrink)
From a twenty-first century partnership between bioethics and neuroscience, the modern field of neuroethics is emerging, and technologies enabling functional neuroimaging with unprecedented sensitivity have brought new ethical, social and legal issues to the forefront. Some issues, akin to those surrounding modern genetics, raise critical questions regarding prediction of disease, privacy and identity. However, with new and still-evolving insights into our neurobiology and previously unquantifiable features of profoundly personal behaviors such as social attitude, value and moral agency, the difficulty of (...) carefully and properly interpreting the relationship between brain findings and our own self-concept is unprecedented. Therefore, while the ethics of genetics provides a legitimate starting point - even a backbone - for tackling ethical issues in neuroimaging, they do not suffice. Drawing on recent neuroimaging findings and their plausible real-world applications, we argue that interpretation of neuroimaging data is a key epistemological and ethical challenge. This challenge is two-fold. First, at the scientific level, the sheer complexity of neuroscience research poses challenges for integration of knowledge and meaningful interpretation of data. Second, at the social and cultural level, we find that interpretations of imaging studies are bound by cultural and anthropological frameworks. In particular, the introduction of concepts of self and personhood in neuroimaging illustrates the interaction of interpretation levels and is a major reason why ethical reflection on genetics will only partially help settle neuroethical issues. Indeed, ethical interpretation of such findings will necessitate not only traditional bioethical input but also a wider perspective on the construction of scientific knowledge. (shrink)
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. (shrink)
Despite the results of David Lewis, Peter Gärdenfors, and others, showing that imaging and classical conditionalization coincide only in the most trivial probabilistic models of belief revision, it turns out that imaging on a proposition A can always be described via Popper function conditionalization on a proposition that entails A. This result generalizes to any method of belief revision meeting certain minimal requirements. The proof is illustrated by an application of imaging in the context of the Monty (...) Hall Problem. (shrink)
Given that visualisations via medical imaging have tremendously increased over the last decades, the overall presence of colour-coded brain slices generated on the basis of functional imaging, i.e. neuroimaging techniques, have led to the assumption of so-called kinds of brains or cognitive profiles that might be especially related to non-healthy humans affected by neurological, neuropsychological or psychiatric syndromes or disorders. In clinical contexts especially, one must consider that visualisations through medical imaging are suggestive in a twofold way. (...)Imaging data not only visually render pathological entities, but also tend to represent objective and concrete evidence for these psychophysical states in question. This article aims to identify key issues in visually rendering psychiatric disorders via functional approaches of imaging within the neurosciences from an epistemological point of view. (shrink)
Gliomas can display marked changes in the concentrations of energy metabolism molecules such as creatine (Cr), phosphocreatine (PCr) and lactate, as measured using magnetic resonance spectroscopy (MRS). Moreover, the BOLD (blood oxygen level dependent) contrast enhancement in functional magnetic resonance imaging (fMRI) can be reduced or missing within or near gliomas, while neural activity is not significantly reduced (so-called neurovascular decoupling), so that the location of functionally eloquent areas using fMRI can be erroneous. In this paper, we adapt a (...) previously developed model of the coupling between neural activation, energy metabolism and hemodynamics, by including the venous dilatation Balloon model of Buxton and Frank. We show that decreasing the cerebral blood flow (CBF) baseline value, or the CBF increase fraction, results in a decrease of the BOLD signal and an increase of the lactate peak during a sustained activation. Baseline lactate and PCr levels are not significantly affected by CBF baseline reduction, but are altered even by a moderate decrease of mitochondrial respiration. Decreasing the total Cr and PCr concentration reduces the BOLD signal after the initial overshoot. In conclusion, we suggest that the coupled use of BOLD fMRI and MRS could contribute to a better understanding of the neurovascular and metabolic decoupling in gliomas. (shrink)
Children seem to have a profound implicit knowledge of human behaviour, because they laugh at Bugs Bunny cartoons where much of the humour depends on animals behaving like humans and our intuitive recognition that this is absurd. Scientists, on the other hand, have problems defining what this 'human difference' is. I suggest these problems are of cultural origin. For example, the industrial revolution and the protestant work ethic have created a world in which work is valued over play, object intelligence (...) over social intelligence, and science and technology over the arts. This may explain why we have so many imaging studies of tool-use and object manipulation, but only four studies of dance, two of pretend play, and one of role-play. Yet in order to understand child development, the evolution of the brain, and the emergence of human self-consciousness, we need to look at social displays-- such as dance, song, image-making and role-play-- which underpin human culture, cooperation and the arts. I will discuss recent brain imaging research on playful versus instrumental behaviour and show how, in conjunction with archaeological data, we can use this to make sense of human evolution. (shrink)
Medical imaging has provided insight into the living body that were not possible beforehand. With these methods a revolution in medical diagnosis and biomedical research has begun. Problematic aspects on the other hand are arising from the highly constructive properties of image production, which use complicated physical and physiological effects. Images are established via highly complicated combinations of technology and contingently chosen mathematical and algorithmic solutions. In addition, image construction follows properties of the human visual and cognitive system to (...) allow for the discrimination of the desired categories. It is no wonder that the visualizations referring to the body also show effects which have no physiological correlation within the body. Still such images are often used as if they were one-to-one correlates of the body. This has impacts, e.g. for their use as standardizing instances, resulting in new definitions of the normed healthy body, sickness or pathologies, maleness and femaleness and in determinisms as opposed to the brain's plasticity and variability, both in time and space, inter- as well as intra-individually. (shrink)
Merging the information from different senses is essential for successful interaction with real-life situations. Indeed, sensory integration can reduce perceptual ambiguity, speed reactions, or change the qualitative sensory experience. It is widely held that integration occurs at later processing stages and mostly in higher association cortices; however, recent studies suggest that sensory convergence can occur in primary sensory cortex. A good model for early convergence proved to be the auditory cortex, which can be modulated by visual and tactile stimulation; however, (...) given the large number and small size of auditory fields, neither human imaging nor microelectrode recordings have systematically identified which fields are susceptible to multisensory influences. To reconcile findings from human imaging with anatomical knowledge from nonhuman primates, we exploited high-resolution imaging (functional magnetic resonance imaging) of the macaque monkey to study the modulation of auditory processing by visual stimulation. Using a functional parcellation of auditory cortex, we localized modulations to individual fields. Our results demonstrate that both primary (core) and nonprimary (belt) auditory fields can be activated by the mere presentation of visual scenes. Audiovisual convergence was restricted to caudal fields [prominently the core field (primary auditory cortex) and belt fields (caudomedial field, caudolateral field, and mediomedial field)] and continued in the auditory parabelt and the superior temporal sulcus. The same fields exhibited enhancement of auditory activation by visual stimulation and showed stronger enhancement for less effective stimuli, two characteristics of sensory integration. Together, these findings reveal multisensory modulation of auditory processing prominently in caudal fields but also at the lowest stages of auditory cortical processing. (shrink)
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. (shrink)
How Technologies of Imaging are Shaping Clinical Research and Practice in Neurology Content Type Journal Article Category Past & Present Pages 315-328 DOI 10.1007/s12376-010-0037-1 Authors Nicolas Kopp, Hôpital de l’HotelDieu Lyon University Hospitals, EspaceEthique Inter-régional 69288 Lyon, Cedex 02 France Journal Medicine Studies Online ISSN 1876-4541 Print ISSN 1876-4533 Journal Volume Volume 1 Journal Issue Volume 1, Number 4.
Modelling became one of the primary tools of mathematical economic research in the twentieth century, but when we look at examples of how nonanalogical models were first built in economics, both the process of making representations and aspects of the representing relation remain opaque. Like early astronomers, economists have to imagine how the hidden parts of their world are arranged and to make images, that is, create models, to represent how they work. The case of the Edgeworth Box, a model (...) widely used for theoretical work in twentieth-century economics, provides a good example to explore the process of making mathematical representations of the economy. It shows how, in making these new representations, conceptual elements were developed which could not have been represented in the older verbal forms of economics. (shrink)
The ability to image the human brain has provided a new perspective for neuropsychologists in their efforts to understand, diagnose, and treat insults to the human brain that might occur as the result of stroke, tumor, traumatic injury, degenerative disease, or errors in development. These new ®ndings are the major theme of this special issue. In our article, we consider brain networks that carry out the functions of attention. We outline several such networks that have been studied in normal and (...) pathological states. These include networks for orienting to sensory stimuli, for maintaining the alert state, and for orchestrating volitional control. (shrink)
Modelling became one of the primary tools of economic research in the 20th century and economists understand their mathematical models as giving some kind of representation of the economic world, one adequate enough for the purpose of reasoning about that world. But when we look at examples of how non-analogical models were first built in economics, both the process of making representations and aspects of the representing relation remain opaque. Like early astronomers, economists have to imagine how the hidden parts (...) of their world are arranged and to make images, that is, create models, to represent how they work. The case of the Edgeworth Box, a widely used model in 20th century economics, provides a good example to explore the role of imagination and images in the process of making representations of the economy. (shrink)
This article is based on ethnographic research conducted between 1998 and 2000 in British Columbia, Canada. In this article Luce brings together the narratives of queer women she interviewed about their experiences of trying to become parents with her own stories about doing the research. Both sets of stories explore the ways in which relationships between people are reproduced and represented through images of sexuality, reproduction, queerness, parents, and families. Shifting between telling about the tensions she experienced while doing ethnographic (...) fieldwork and retelling women's stories about how their relationships to partners, fetuses, babies, and donors were perceived, the article draws attention to both political and methodological questions. (shrink)
The influence of sediment oxygen heterogeneity, due to bioturbation, on diffusive oxygen flux was investigated. Laboratory experiments were carried out with 3 macrobenthic species presenting different bioturbation behaviour patterns: the polychaetes Nereis diversicolor and Nereis virens, both constructing ventilated galleries in the sediment column, and the gastropod Cyclope neritea, a burrowing species which does not build any structure. Oxygen two-dimensional distribution in sediments was quantified by means of the optical planar optode technique. Diffusive oxygen fluxes (mean and integrated) and a (...) variability index were calculated on the captured oxygen images. All species increased sediment oxygen heterogeneity compared to the controls without animals. This was particularly noticeable with the polychaetes because of the construction of more or less complex burrows. Integrated diffusive oxygen flux increased with oxygen heterogeneity due to the production of interface available for solute exchanges between overlying water and sediments. This work shows that sediment heterogeneity is an important feature of the control of oxygen exchanges at the sediment–water interface. (shrink)
William Uttal's The new phrenology is a broad attack on localization in cognitive neuroscience. He argues that even though the brain is a highly differentiated organ, "high level cognitive functions" should not be localized in specific brain regions. First, he argues that psychological processes are not well-defined. Second, he criticizes the methods used to localize psychological processes, including imaging technology: he argues that variation among individuals compromises localization, and that the statistical methods used to construct activation maps are flawed. (...) Neither criticism is compelling. First, as we illustrate, there are behavioral measures which offer at least weak constraints on psychological attribution. Second, though imaging does face methodological difficulties associated with variation among individuals, these are broadly acknowledged; moreover, his specific criticisms of the imaging work, and in particular of fMRI, misrepresent the methodology. In concluding, we suggest a way of framing the issues that might allow us to resolve differences between localizationist models and more distributed models empirically. (shrink)
& Functional brain imaging offers new opportunities for the begin with single-subject (preprocessed) scan series, and study of that most pervasive of cognitive conditions, human consider the patterns of all voxels as potential multivariate consciousness. Since consciousness is attendant to so much encodings of phenomenal information. Twenty-seven subjects of human cognitive life, its study requires secondary analysis from the four studies were analyzed with multivariate of multiple experimental datasets. Here, four preprocessed methods, revealing analogues of phenomenal structures, datasets from (...) the National fMRI Data Center are considered: particularly the structures of temporality. In a second Hazeltine et al., Neural activation during response competi- interpretive approach, artificial neural networks were used tion; Ishai et al., The representation of objects in the human to detect a more explicit prediction from phenomenology, occipital and temporal cortex; Mechelli et al., The effects of namely, that present experience contains and is inflected by presentation rate during word and pseudoword reading; and past states of awareness and anticipated events. In all of 21 Postle et al., Activity in human frontal cortex associated with subjects in this analysis, nets were successfully trained to spatial working memory and saccadic behavior. The study of extract aspects of relative past and future brain states, in consciousness also draws from multiple disciplines. In this comparison with statistically similar controls. This exploratory article, the philosophical subdiscipline of phenomenology study thus concludes that the proposed methods for provides initial characterization of phenomenal structures ‘‘neurophenomenology’’ warrant further application, includ- conceptually necessary for an analysis of consciousness. These ing the exploration of individual differences, multivariate structures include phenomenal intentionality, phenomenal differences between cognitive task conditions, and explora- superposition, and experienced temporality.. (shrink)
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. (shrink)
Anatomo-functional studies in humans point out that handedness and language-related functional laterality are not correlated – except during language production; and that the convergence of language and hand control is located in the precentral gyrus, whereas executive functions required by movement imitation and phonological and semantic processing converge onto Broca's area. Multiple domains are likely to be actors in language evolution. Footnotes1 Nathalie Tzourio-Mazoyer is the corresponding author for this commentary.
Soltis' paper contains little data on the underlying neural substrate of the discussed signal function of early infant crying – probably because there is amazingly little known about it. We here discuss the interest of functional neuroimaging as an objective measurement of brain activity in (1) early infants during crying and (2) parents hearing their offspring cry.
Calcium plays an important role in regulating a great variety of neuronal processes, and many efforts are made to generate gadolinium complexes that can act as calcium-dependent MRI contrast agents. A series of gadolinium chelate complexes based on DO3A were developed, bearing phosphonate groups as an additional coordination sites, which is hypothesized to change relaxivity in magnetic resonance experiments dynamically with Ca2+ concentration. Different lengths of the phosphonate side chains are expected to lead to different binding constants of the phosphonate (...) - gadolinium bonds. The latter property can be exploited for fine-tuning the sensitivity of the agent to calcium ion concentration. (shrink)
Smart MR contrast agents exhibit modulation of their relaxivity by specific physiological or biochemical trigger-events, while targeted MR contrast agents are envisioned to deliver the large gadolinium chelates into the target tissue. In an effort to develop novel smart and targeted MR contrast agents, the series of the DO3A based multifunctional chelating agents with the variable length of the side chain has been synthesized. They serve as valuable multipurpose precursors for contrast agents based on gadolinium chelates in the design of (...) relaxometric MR probes. The presence of the amino group in the side chain of the macrocycle allows for conversion into various functional groups (aminophosponates, aminocarboxylates, etc.) or for conjugation with different biomolecules, dyes, and polymers. Choice of the functional groups depends on the.. (shrink)
Disorders of consciousness (DOC) raise profound scientific, clinical, ethical, and philosophical issues. Growing knowledge on fundamental principles of brain organization in healthy individuals offers new opportunities for a better understanding of residual brain function in DOCs. We here discuss new perspectives derived from a recently proposed scheme of brain organization underlying consciousness in healthy individuals. In this scheme, thalamo-cortical networks can be divided into two, often antagonistic, global systems: (i) a system of externally oriented, sensory-motor networks (the ‘‘extrinsic’’ system); and (...) (ii) a system of inward-oriented networks (the ‘‘intrinsic’’ or default system). According to this framework, four distinct mental states would be possible that could be relevant for understanding DOCs. In normal healthy volunteers and locked-in syndrome patients, a state of high functionality of both the extrinsic and intrinsic or default systems is expected — associated with full awareness of environment and self. In this case, mental imagery tasks combined with fMRI can be used to detect covert awareness in patients that are unable to communicate. According to the framework, two complementary states of system imbalance are also possible, in which one system is in a hyperfunctional state, while the other is hypoactive. Extrinsic system hyperfunction is expected to lead to a state of total sensory-motor ‘‘absorption’’ or ‘‘lost self.’’ In contrast, intrinsic or default system hyperfunction is expected to lead to a state of complete detachment from the external world. A state where both extrinsic and intrinsic systems are hypofunctional is predicted to lead to markedly impaired consciousness as seen in DOCs. Finally, we review the potential use of ultra-slow fluctuations in BOLD signal as a tool for assessing the functional integrity of extrinsic and intrinsic systems during ‘‘resting state’’ fMRI acquisitions.. (shrink)
Imagine you are an editor at a well respected national magazine with a rich history in photojournalism. The magazine is ready for publication but there is a problem with the cover. The photograph chosen for the cover does not quite fit the vertical format of the magazine and no other picture has all the qualities to best illustrate the cover story. No problem! With a computer, an operator simply moves the objects in the photograph closer together to fit the magazine (...) format perfectly. The finished product is virtually undetectable, even by experts. (shrink)
