& These experiments use functional magnetic resonance imaging (fMRI) to reveal neural activity uniquely associated with perception of biological motion. We isolated brain areas activated during the viewing of point-light figures, then compared those areas to regions known to be involved in coherent-motion perception and kinetic-boundary perception. Coherent motion activated a region matching previous reports of human MT/MST complex located on the temporo-parietooccipital junction. Kinetic boundaries activated a region posterior and adjacent to human MT previously identified as the kinetic-occipital (KO) region or the lateral-occipital (LO) complex. The pattern of activation during viewing of biological

Functional magnetic resonance imaging was used to identify the neural correlates of Chinese character and word reading. The Chinese stimuli were presented visually, one at a time. Subjects covertly generated a word that was semantically related to each stimulus. Three sorts of Chinese items were used: single characters having precise meanings, single characters having vague meanings, and two-character Chinese words. The results indicated that reading Chinese is characterized by extensive activity of the neural systems, with strong left lateralization of frontal (BAs 9 and 47) and temporal (BA 37) cortices and right lateralization of visual systems (BAs 17–19), parietal lobe (BA 3), and cerebellum. The location of peak activation in the left frontal regions coincided nearly completely both for vague- and precisemeaning characters as well as for two-character words, without dissociation in laterality patterns. In addition, left frontal activations were modulated by the ease of semantic retrieval. The present results constitute a challenge to the deeply ingrained belief that activations in reading single characters are right lateralized, whereas activations in reading two-character words are left lateralized.

Written Chinese as logographic script differs notably from alphabets such as English in visual form, orthography, phonology, and semantics. Thus, research on the Chinese language is important to advance our understanding of the universality and particularity of the organization of language systems in the brain. In this study, we examine the neural systems associated with logographic reading using functional magnetic resonance imaging. Two experimental tasks were devised, one based on semantic decision and the other on homophone decision. Compared to the fixation baseline, peak activations resulting from semantic as well as homophony decisions were localized in the left middle frontal gyrus (BA 9). Left inferior frontal cortex also mediated Chinese processing. In addition, more right hemisphere cortical regions (i.e., BAs 47/45, 7, 40/39, and the right visual system) were involved in reading Chinese relative to reading English. This is attributed to the square shape of the logograph which requires an elaborated analysis of the spatial information and locations of various strokes comprising the logographic character. We suggest that the left middle frontal area (BA 9) coordinates and integrates the intensive visuospatial analysis demanded by logographs ’ square configuration and the semantic (or phonological) analysis required by the present experimental tasks. Our study has implicated brain regions common to both logographic and alphabetic languages as well as brain regions specialized in processing logographs. © 2001 Academic Press

It is well known that performance on a given trial of a cognitive task is affected by the nature of previous trials. For example, conflict effects on interference tasks, such as the Stroop task, are reduced subsequent to high-conflict trials relative to low-conflict trials. This interaction effect between previous and current trial types is called bconflict adaptationQ and thought to be due to processing adjustments in cognitive control. The current study aimed to identify the neural substrates of cognitive control during conflict adaptation by isolating neural correlates of reduced conflict from those of increased cognitive control. We expected cognitive control to be implemented by prefrontal cortex through context-specific modulation of posterior regions involved in sensory and motor aspects of task performance. We collected event-related fMRI data on a color-word naming Stroop task and found distinct fronto-parietal networks of current trial conflict detection and conflict adaptation through cognitive control. Conflict adaptation was associated with increased activity in left middle frontal gyrus (GFm) and superior frontal gyrus (GFs), consistent with increased cognitive control, and with decreased activity in bilateral prefrontal and parietal cortices, consistent with reduced response conflict. Psychophysiological interaction analysis (PPI) revealed that cognitive control activation in GFs and GFm was accompanied by increased functional integration with bilateral inferior frontal, right temporal and parietal areas, and the anterior cerebellum. These data suggest that cognitive control is implemented by medial and lateral prefrontal cortices that bias processes in regions that have been implicated in high-level perceptual and motor processes.

Finding a unifying concept behind the diversity of signs and symptoms in schizophrenia is a central challenge to contemporary research. A neo-Bleulerian unitary model is described, which defines the illness as a neurodevelopmentally derived “misconnection syndrome, ” involving connections between cortical regions and the cerebellum mediated through the thalamus (the cortico-cerebellar-thalamic-cortical circuit [CCTCC]). An abnormality in this circuitry, normally used to coordinate both motor and mental activity, leads to misconnections in many aspects of mental activity, or “cognitive dysmetria. ” As Bleuler originally proposed, “thought disorder ” is the primary defining feature of schizophrenia, rather than the more obvious signs and symptoms such as delusions and hallucinations. Cognitive dysmetria, or a disorder in the CCTCC, may provide a heuristic theoretical framework for strategies to explore etiology, pathophysiology, intervention, or prevention. Arch Gen Psychiatry. 1999;56:781-787 At present the most important problem in schizophrenia research is not finding the gene or localizing it in the brain and understanding its neural circuits. Our most important problem is identifying the correct target at which to aim our powerful new scientific weapons. Our most pressing problem is at the clinical level: defining what schizophrenia is. See also page 791 This overview reviews the original definition of schizophrenia, as formulated by Euger Bleuler, and proposes a model for updating it within the context of contemporary neuroscience. It derives from the need to reconceptualize the phenotype of the illness for contemporary translational research that moves from the clinical to the basic and back to the clinical again; eg, the informed choice of candidate genes, the development of animal models for this most human of diseases, or the identification of the neural circuits that improved treatments might modify. This overview argues that, for these purposes, the definition of schizophrenia

We used fMRI to examine neural responses when subjects experienced a tactile stimulus that was either self-produced or externally produced. The somatosensory cortex showed increased levels of activity when the stimulus was externally produced. In the cerebellum there was less activity associated with a movement that generated a tactile stimulus than with a movement that did not. This difference suggests that the cerebellum is involved in predicting the specific sensory consequences of movements and providing the signal that is used to attenuate the sensory response to self-generated stimulation. In this paper, we use regression analyses to test this hypothesis explicitly. Specifically, we predicted that activity in the cerebellum contributes to the decrease in somatosensory cortex activity during self-produced tactile stimulation. Evidence in favor of this hypothesis was obtained by demonstrating that activity in the thalamus and primary and secondary somatosensory cortices significantly regressed on activity in the cerebellum when tactile stimuli were self-produced but not when they were externally produced. This supports the proposal that the cerebellum is involved in predicting the sensory consequences of movements. In the present study, this prediction is accurate when tactile stimuli are self-produced relative to when they are externally produced, and is therefore used to attenuate the somatosensory response to the former type of tactile stimulation but not the latter.

CONTENTS LIST OF FIGURES..............................................................................................................VII LIST OF TABLES..................................................................................................................X CHAPTER 1: INTRODUCTION.............................................................................................1 THE ISSUES OF MOTOR CONTROL ...........................................................................................1 HISTORY OF THE BASAL GANGLIA .........................................................................................3 HYPOTHESIS ..........................................................................................................................7 ORGANIZATION OF DISSERTATION.................................

This article presents a new high-resolution atlas template of the human, cerebellum and brainstem, based on the anatomy of 20 young healthy individuals. The atlas is spatially unbiased, i.e., the location of each structure is equal to the expected location of that structure across individuals in MNI space, a result that is cross-validated with an independent sample of 16 individuals. At the same time, the new template preserves the anatomical detail of cerebellar structures through a nonlinear atlas generation algorithm. In comparison to current whole-brain templates, it allows for an improved voxel-byvoxel normalization for functional MRI and lesion analysis. Alignment to the template requires that the cerebellum and brainstem are isolated from the surrounding tissue, a process for which an automated algorithm has been developed. Compared to normalization to the MNI whole-brain template, the new method strongly improves the alignment of individual fissures, reducing their spatial spread by 60%, and improves the overlap of the deep cerebellar nuclei. Applied to functional MRI data, the new normalization technique leads to a 5–15 % increase in peak t values and in the activated volume in the cerebellar cortex for movement vs. rest contrasts. This indicates that the new template significantly improves the overlap of functionally equivalent cerebellar regions across individuals. The template and software are freely available as an SPM-toolbox, which also allows users to relate the new template to the annotated volumetric

The classical notion that the cerebellum and the basal ganglia are dedicated to motor control is under dispute given increasing evidence of their involvement in non-motor functions. Is it then impossible to characterize the functions of the cerebellum, the basal ganglia and the cerebral cortex in a simplistic manner? This paper presents a novel view that their computational roles can be characterized not by asking what are the "goals" of their computation, such as motor or sensory, but by asking what are the "methods " of their computation, specifically, their learning algorithms. There is currently enough anatomical, physiological, and theoretical evidence to support the hypotheses that the cerebellum is a specialized organism for supervised learning, the basal ganglia are for reinforcement learning, and the cerebral cortex is for unsupervised learning. This paper investigates how the learning modules specialized for these three kinds of learning can be assembled into goa...

and acquisition in this language. D 2004 Elsevier Inc. All rights reserved. Keywords: Noun; Verb; Chinese; fMRI Introduction A central issue in the cognitive neuroscience of language is how the brain represents linguistic categories such as nouns, verbs, and adjectives. Neuropsychological studies of brain-injured patients and neuroimaging studies of normal speakers have both suggested specific brain areas that respond to different linguistic categories, in particular, object names (nouns) and action names (verbs). For example, while Broca's aphasics have significant problems with action/verb naming, Wernicke's aphasics typically experience difficulties in producing nouns (Bates et al., 1991; Caramazza and Hillis, 1991; Miceli et al., 1988; Shapiro and Caramazza, 2003). PET studies reveal that nouns and verbs elicit responses from different regions of the brain: nouns or object names activate the posterior regions (occipitotemporal areas, including the visual cortex) while verbs or