Science posts

See science posts on page 69 below.

    • 2010
    • Gordon L. Shulman
    • Right Hemisphere Dominance during Spatial Selective Attention and Target Detection Occurs Outside the Dorsal Frontoparietal Network
    • Spatial selective attention is widely considered to be right hemisphere dominant. Previous functional magnetic resonance imaging studies, however, have reported bilateral blood-oxygenation-level-dependent responses in dorsal frontoparietal regions during anticipatory shifts of attention to a location (Kastner et al., 1999; Corbetta et al., 2000; Hopfinger et al., 2000). Right-lateralized activity has mainly been reported in ventral frontoparietal regions for shifts of attention to an unattended target stimulus (Arrington et al., 2000; Corbetta et al., 2000). However, clear conclusions cannot be drawn from these studies because hemispheric asymmetries were not assessed using direct voxelwise comparisons of activity in left and right hemispheres. Here, we used this technique to measure hemispheric asymmetries during shifts of spatial attention evoked by a peripheral cue stimulus and during target detection at the cued location. Stimulus-driven shifts of spatial attention in both visual..
    • Gordon L. Shulman, Daniel L. W. Pope, Serguei V. Astafiev, Mark P. McAvoy, Abraham Z. Snyder, Maurizio Corbetta
    • 2013
    • Maurizio Corbetta
    • Spatial neglect and attention networks
    • Unilateral spatial neglect is a common neurological syndrome following predominantly right hemisphere injuries to ventral fronto-parietal cortex. We propose that neglect reflects deficits in the coding of saliency, control of spatial attention, and representation within an egocentric frame of reference, in conjunction with non-spatial deficits of reorienting, target detection, and arousal/vigilance. In contrast to theories that link spatial neglect to structural damage of specific brain regions, we argue that neglect is better explained by the physiological dysfunction of distributed cortical networks. The ventral lesions in right parietal, temporal, and frontal cortex that cause neglect directly impair non-spatial functions and hypoactivate the right hemisphere, inducing abnormalities in task-evoked activity and functional connectivity of a dorsal frontal-parietal network that controls spatial attention. The anatomy and right hemisphere dominance of neglect follows from the anatomy ..
    • Maurizio Corbetta, Gordon L. Shulman
    • 2002
    • Maurizio Corbetta
    • Control of goal-directed and stimulus-driven attention in the brain
    • We review evidence for partially segregated networks of brain areas that carry out different attentional functions. One system, which includes parts of the intraparietal cortex and superior frontal cortex, is involved in preparing and applying goal-directed (top-down) selection for stimuli and responses. This system is also modulated by the detection of stimuli. The other system, which includes the temporoparietal cortex and inferior frontal cortex, and is largely lateralized to the right hemisphere, is not involved in top-down selection. Instead, this system is specialized for the detection of behaviourally relevant stimuli, particularly when they are salient or unexpected. This ventral frontoparietal network works as a 'circuit breaker' for the dorsal system, directing attention to salient events. Both attentional systems interact during normal vision, and both are disrupted in unilateral spatial neglect.
    • 2009
    • Pascal Molenberghs
    • Is the mirror neuron system involved in imitation? A short review and meta-analysis
    • It has been suggested that the mirror neuron system provides an important neural substrate for humans’ ability to imitate. Mirror neurons have been found during single-cell recordings in monkeys in area F5 and PF. It is believed that the human equivalent of this mirror system in humans is the pars opercularis of the inferior frontal gyrus (area 44) and the rostral part of the inferior parietal lobule. This article critically reviews published fMRI studies that examined the role of frontal and parietal brain regions in imitation. A meta-analysis using activation likelihood estimation (ALE) revealed that the superior parietal lobule, inferior parietal lobule, and the dorsal premotor cortex but not the inferior frontal gyrus, are all commonly involved in imitation. An additional meta-analysis using a label-based review confirmed that in the frontal lobe, the premotor cortex rather than the inferior frontal gyrus is consistently active in studies investigating imitation. In the parietal ..
    • Pascal Molenberghs, Ross Cunnington, Jason B. Mattingley
    • Imitation, fMRI, Mirror neuron system
    • 2004
    • Giovanni Buccinoa
    • The mirror neuron system and action recognition
    • Mirror neurons, first described in the rostral part of monkey ventral premotor cortex (area F5), discharge both when the animal performs a goal-directed hand action and when it observes another individual performing the same or a similar action. More recently, in the same area mirror neurons responding to the observation of mouth actions have been also found. In humans, through an fMRI study, it has been shown that the observation of actions performed with the hand, the mouth and the foot leads to the activation of different sectors of Broca’s area and premotor cortex, according to the effector involved in the observed action, following a somatotopic pattern which resembles the classical motor cortex homunculus. These results strongly support the existence of an execution-observation matching system (mirror neuron system). It has been proposed that this system is involved in action recognition. Experimental evidence in favor of this hypothesis both in the monkey and humans are shortl..
    • Giovanni Buccinoa, Ferdinand Binkofskib, Lucia Riggioa
    • 2005
    • Mirella Dapretto
    • Understanding emotions in others: mirror neuron dysfunction in children with autism spectrum disorders
    • To examine mirror neuron abnormalities in autism, high-functioning children with autism and matched controls underwent fMRI while imitating and observing emotional expressions. Although both groups performed the tasks equally well, children with autism showed no mirror neuron activity in the inferior frontal gyrus (pars opercularis). Notably, activity in this area was inversely related to symptom severity in the social domain, suggesting that a dysfunctional 'mirror neuron system' may underlie the social deficits observed in autism.
    • Mirella Dapretto, Mari S Davies, Jennifer H Pfeifer, Ashley A Scott, Marian Sigman, Susan Y Bookheimer, Marco Iacoboni
    • 2004
    • Giacomo Rizzolatti
    • The mirron-neuron system
    • A category of stimuli of great importance for primates, humans in particular, is that formed by actions done by other individuals. If we want to survive, we must understand the actions of others. Furthermore, without action understanding, social organization is impossible. In the case of humans, there is another faculty that depends on the observation of others' actions: imitation learning. Unlike most species, we are able to learn by imitation, and this faculty is at the basis of human culture. In this review we present data on a neurophysiological mechanism—the mirror-neuron mechanism—that appears to play a fundamental role in both action understanding and imitation. We describe first the functional properties of mirror neurons in monkeys. We review next the characteristics of the mirror-neuron system in humans. We stress, in particular, those properties specific to the human mirror-neuron system that might explain the human capacity to learn by imitation. We conclude by discussing..
    • Giacomo Rizzolatti, Laila Craighero
    • 2010
    • S.G. Shamay-Tsoorya
    • The origins of originality: The neural bases of creative thinking and originality
    • Although creativity has been related to prefrontal activity, recent neurological case studies postulate that patients who have left frontal and temporal degeneration involving deterioration of language abilities may actually develop de novo artistic abilities. In this study, we propose a neural and cognitive model according to which a balance between the two hemispheres affects a major aspect of creative cognition, namely, originality. In order to examine the neural basis of originality, that is, the ability to produce statistically infrequent ideas, patients with localized lesions in the medial prefrontal cortex (mPFC), inferior frontal gyrus (IFG), and posterior parietal and temporal cortex (PC), were assessed by two tasks involving divergent thinking and originality. Results indicate that lesions in the mPFC involved the most profound impairment in originality. Furthermore, precise anatomical mapping of lesions indicated that while the extent of lesion in the right mPFC was associ..
    • S.G. Shamay-Tsoorya, N. Adlera, J. Aharon-Peretzb, D. Perrya, N. Mayselessa
    • Creativity, Originality, Medial prefrontal cortex, Lateralization
    • 2008
    • Jonathan St. B. T. Evan
    • Dual-Processing Accounts of Reasoning, Judgment, and Social Cognition
    • This article reviews a diverse set of proposals for dual processing in higher cognition within largely disconnected literatures in cognitive and social psychology. All these theories have in common the distinction between cognitive processes that are fast, automatic, and unconscious and those that are slow, deliberative, and conscious. A number of authors have recently suggested that there may be two architecturally (and evolutionarily) distinct cognitive systems underlying these dual-process accounts. However, it emerges that (a) there are multiple kinds of implicit processes described by different theorists and (b) not all of the proposed attributes of the two kinds of processing can be sensibly mapped on to two systems as currently conceived. It is suggested that while some dual-process theories are concerned with parallel competing processes involving explicit and implicit knowledge systems, others are concerned with the influence of preconscious processes that contextualize and ..
    • 2010
    • Deanna J. Greene
    • Hemispheric differences in attentional orienting by social cues
    • Research points to a right hemisphere bias for processing social stimuli. Hemispheric specialization for attention shifts cued by social stimuli, however, has been rarely studied. We examined the capacity of each hemisphere to orient attention in response to social and nonsocial cues using a lateralized spatial cueing paradigm. We compared the up/down orienting effects of eye gaze cues, arrow cues, and peripheral cues (change in luminance). Results revealed similar cueing effects in each visual field for nonsocial cues, but asymmetric effects for social cues. At both short (150 ms) and long (950 ms) cue-target intervals, gaze cueing was significant in the LVF, but not in the RVF. Thus, there is a right hemisphere bias for attentional orienting cued by social stimuli, but not for attentional orienting cued by nonsocial stimuli. This supports a theory of a separate neural system for socially cued orienting of attention, as well as a theory of separate parallel and simultaneous neural s..
    • Deanna J. Greene, Eran Zaidel
    • Lateralized gaze cues, Hemispheric specialization, Spatial attention, Exogenous orienting, Reflexive orienting