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)

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.

Having a self is associated with important advantages for an organism.These advantages have been suggested to include mechanisms supporting elaborate capacities for planning, decision-making, and behavioral control. Acknowledging such functionality offers possibilities for obtaining traction on investigation of neural correlates of selfhood. A method that has potential for investigating some of the brain-based properties of self arising in behavioral contexts varying in requirements for such behavioral guidance and control is functional brain imaging. Data obtained with this method are (...) beginning to converge on a set of brain areas that appear to play a significant role in permitting conscious access to representational content having reference to self as an embodied and independent experiencer and agent. These areas have been identified in a variety of imaging contexts ranging from passive state conditions in which they appear to manifest ongoing activity associated with spontaneous and typically ‘self-related’ cognition, to tasks targeting explicitly experienced properties of self, to demanding task conditions where activity within them is attenuated in apparent redirection of cognitive resources in the service of task guidance and control. In this paper, these data will be reviewed and a hypothesis presented regarding a significant role for these areas in enabling degrees of self-awareness and participating in the management of such behavioral control. (shrink)

Functional imaging techniques, such as positron emission tomography and functional magnetic resonance imaging, present a unique opportunity to examine, in humans, the cerebral representation of space in vivo. Space is ubiquitous and not a unitary phenomenon, and the brain uses visual, vestibular and proprioceptive inputs to produce multiple representations of space subserving spatial cognition, ranging from gaze control to remembering multiple complex large-scale environments. Functional imaging studies have shown the importance of the parietal cortex (...) in perceptual, motor, attention and working memory aspects of body-centred human spatial cognition. Functional imaging has also revealed pathways in humans homologous to those found in monkeys for the separate processing of spatial location and object identity. There are further suggestions of similar differentiation in working memory. The importance of the medial temporal region in the recall of spatial location has been confirmed also and novel virtual reality paradigms are now providing insights into the cerebral representation of spatially-extended large-scale environments. We still have much to learn about the cerebral representation of space in the human brain and functional brain imaging, in concert with patient studies and animal models, will allow us to continue investigating. (shrink)

If we assume that consciousness is a natural biological phenomenon in the brain, should we expect the current brain sensing and imaging methods to somehow ‘discover’ consciousness? The answer depends on the following points: What kind of level of biological organization do we assume consciousness to be? What would count as the discovery of this level? What are the levels of organization from which the currently available research instruments pick signals and acquire data? Single-cell recordings, PET, fMRI, EEG and (...) MEG pick different types of signals from different levels of organization in the brain. However, it seems they do not manage to pick signals that would allow the direct visualization and reconstruction of the higher levels of electrophysiological organization that are crucial for the empirical discovery and theoretical explanation of consciousness. The message of the present paper is twofold: On the one hand, we should be aware of the practical limitations of the currently available methods of cognitive neuroscience and not read too much into the images produced by them. On the other hand, the present limitations could be overcome by more sophisticated methods in the future. Therefore, contrary to what several philosophers have argued, the empirical discovery of consciousness in the brain is not impossible in principle. (shrink)

Since the mid‐1980s, psychologists and neuroscientists have used brain imaging to test hypotheses about human thought processes and their neural instantiation. In just three decades, functional neuroimaging has been transformed from a crude clinical tool to a widely used research method for understanding the human brain and mind. Such rapidly achieved success is bound to evoke skepticism. A degree of skepticism toward new methods and ideas is both inevitable and useful in any field. It is especially valuable in (...) a science as young as cognitive neuroscience and its even younger siblings, social and affective neuroscience. Healthy skepticism encourages us to check our assumptions, recognize the limitations of our methods, and proceed thoughtfully. Skepticism itself, however, also must be examined.In this article, I review the most commonly voiced criticisms of functional neuroimaging. In the spirit of healthy skepticism, I will critically examine these criticisms themselves. Each contains at least a kernel of truth, although I will argue that in some cases the kernel has been overextended in ways that are inaccurate or misleading. (shrink)

Rapid technological advances have produced a variety of novel techniques that allow a comprehensive assessment of brain function to be combined with detailed information about brain structure and connectivity. Any assessment that is based on exhibited behavior after brain injury will be prone to error for a number of reasons. These questions are explored in the context of recent studies in both healthy populations and brain injured patients that have sought to investigate covert awareness through the use of functional (...) neuroimaging. Those circumstances in which functional magnetic resonance imaging data can be used to infer awareness in the absence of a behavioral response are contrasted with those circumstances in which it cannot. This distinction is fundamental for understanding and interpreting patterns of brain activity following acute brain injury and has implications for clinical care, diagnosis, prognosis, and medicolegal decision-making after serious brain injury. (shrink)

Mechanistic explanations satisfy widely held norms of explanation: the ability to manipulate and answer counterfactual questions about the explanandum phenomenon. A currently debated issue is whether any nonmechanistic explanations can satisfy these explanatory norms. Weiskopf argues that the models of object recognition and categorization, JIM, SUSTAIN, and ALCOVE, are not mechanistic yet satisfy these norms of explanation. In this article I argue that these models are mechanism sketches. My argument applies recent research using model-based functional magnetic resonance imaging, (...) a novel neuroimaging method whose significance for current debates on psychological models and mechanistic explanation has yet to be explored. (shrink)

The approach of Revonsuo is criticised as being based on a misplaced emphasis on coupled oscillatory dynamics, as well as on too limited an approach to recent advances in brain imaging. This results in the nature of attention as a basic component in consciousness being ignored, and prevents any attempt to attack the crucial problem for consciousness of inner experience: of ‘what it is like to be’.

After severe brain injury, one of the key challenges for medical doctors is to determine the patient’s prognosis. Who will do well? Who will not do well? Physicians need to know this, and families need to do this too, to address choices regarding the continuation of life supporting therapies. However, current prognostication methods are insufficient to provide a reliable prognosis. -/- Functional Magnetic Resonance Imaging (MRI) holds considerable promise for improving the accuracy of prognosis in acute brain injury (...) patients. Nonetheless, research on functional MRI in the intensive care unit context is ethically challenging. These studies raise several ethical issues that have not been addressed so far. In this article, Prof. Charles Weijer and his co-workers provide a framework for researchers and ethics committees to design and review these studies in an ethically sound way. (shrink)

This paper discusses features of an epistemically valuable form of evidence that raise troubles for received and new epistemological treatments of experimental evidence.