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The spatial location of an object can be represented in two frames of reference: egocentric (relative to the observer's body or body parts) and allocentric (relative to another object independent of the observer). The object positions relative to the two frames can be either congruent (e.g., both left or both right) or incongruent (e.g., one left and one right). Most of the previous studies, however, did not discriminate between the two types of spatial conflicts. To investigate the common and specific neural mechanisms underlying the spatial congruency effect induced by the two reference frames, we adopted a 3 (type of task: allocentric, egocentric, and color) × 2 (spatial congruency: congruent vs. incongruent) within-subject design in this fMRI study. The spatial congruency effect in the allocentric task was induced by the task-irrelevant egocentric representations, and vice versa in the egocentric task. The nonspatial color task was introduced to control for the differences in bottom-up stimuli between the congruent and incongruent conditions. Behaviorally, significant spatial congruency effect was revealed in both the egocentric and allocentric task. Neurally, the dorsal-medial visuoparietal stream was commonly involved in the spatial congruency effect induced by the task-irrelevant egocentric and allocentric representations. The right superior parietal cortex and the right precentral gyrus were specifically involved in the spatial congruency effect induced by the irrelevant egocentric and allocentric representations, respectively. Taken together, these results suggested that different subregions in the parieto-frontal network played different functional roles in the spatial interaction between the egocentric and allocentric reference frame. Hum Brain Mapp 38:2112-2127, 2017. © 2017 Wiley Periodicals, Inc.

An object’s location can be represented either relative to an observer’s body effectors (egocentric reference frame) or relative to another external object (allocentric reference frame). In non-spatial tasks, an object’s task-irrelevant egocentric position conflicts with the side of a task-relevant manual response, which defines the classical Simon effect. Growing evidence suggests that the Simon effect occurs not only based on conflicting positions within the egocentric but also within the allocentric reference frame. Although neural mechanisms underlying the egocentric Simon effect have been extensively researched, neural mechanisms underlying the allocentric Simon effect and their potential interaction with those underlying its egocentric variant remain to be explored. In this fMRI study, spatial congruency between the task-irrelevant egocentric and allocentric target positions and the task-relevant response hand was orthogonally manipulated. Behaviorally, a significant Simon effect was observed for both reference frames. Neurally, three sub-regions in the frontoparietal network were involved in different aspects of the Simon effect, depending on the source of the task-irrelevant object locations. The right precentral gyrus, extending to the right SMA, was generally activated by Simon conflicts, irrespective of the spatial reference frame involved, and showed no additive activity to Simon conflicts. In contrast, the right postcentral gyrus was specifically involved in Simon conflicts induced by task-irrelevant allocentric, rather than egocentric, representations. Furthermore, a right lateral frontoparietal network showed increased neural activity whenever the egocentric and allocentric target locations were incongruent, indicating its functional role as a mismatch detector that monitors the discrepancy concerning allocentric and egocentric object locations.

A 58-year-old man with history of multiple episodes of left arm weakness and numbness. He was admitted to the emergency room with weakness of the left arm of 1 h duration. Multimodal CT imaging revealed an area of prolonged MTT with preserved blood volume at the right precentral gyrus (Fig. 99.1a–c); CTA revealed tight stenosis at the origin of the right ICA and MRI showed multiple areas of diffusion restriction in thr right ACA-MCA and MCA-PCA watershed territory (Fig. 99.1d–f).

Earlier studies demonstrated that adult emotional competences (EC) can be improved through relatively brief training. This increase has been investigated, thus far, using self-reported questionnaires and behavioral data. The aim of the present study was to evaluate the cerebral correlates underlying improvement in EC. An experimental group received an EC training and a control group received brief sessions of drama improvisation. Participants viewed negative, positive, and neutral pictures while attempting to decrease, increase, or not modulate their emotional reactions. Subjective reactions were assessed via on-line ratings. After the intervention, the training group showed less cerebral activity as compared to the control group within different regions related to emotional regulation and attention including prefrontal regions and the bilateral inferior parietal lobule, the right precentral gyrus and the intraparietal sulcus. These results suggest increased neural efficiency in the training group as a result of emotional competen cies training.

A 39-year-old man with a history of sickle cell disease (SCD) presented with left leg weakness. He had a normal CT head and CT angiogram, but MRI head showed multiple acute bilateral cortical infarcts including in the right precentral gyrus. The MRI findings were more in keeping with an embolic source rather than stroke related to SCD, although it could not be ruled out. He also had an echocardiogram which revealed a patent foramen ovale. He was treated with antiplatelet therapy and also had red blood cell exchange transfusion. His symptoms improved significantly and he was discharged with follow-up as an outpatient and a cardiology review.

The current study investigated the neural correlates of both hedonic and eudaimonic happiness. Seventeen students underwent fMRI while cued with written sentences describing three classes of life events: Hedonic events (HE), eudaimonic events (EE) and neutral events (NE). We asked participants to imagine and empathize with all these event types. Results showed that, compared to NE, both HE and EE activated a network involving frontal, temporal and parietal regions, as well as subcortical structures. However, in the HE/EE comparison, HE showed enhanced activity in frontal medial/middle regions and anterior cingulate cortex; by contrast, EE showed increased activity in the right precentral gyrus. Findings suggest that hedonic and eudaimonic happiness activate similar neural correlates. However, both kinds of happiness are also associated with distinctive brain areas serving distinctive functions.

Studies have converged in their findings of relatively less gray matter volume (GMV) in developmental dyslexia in bilateral temporoparietal and left occipitotemporal cortical regions. However, the interpretation of these results has been difficult. The reported neuroanatomical differences in dyslexia may be causal to the reading problems, following from, for example, neural migration errors that occurred during early human development and before learning to read. Alternatively, less GMV may represent the consequence of an impoverished reading experience, akin to the experience-dependent GMV differences attributed to illiterate compared with literate adults. Most likely, a combination of these factors is driving these observations. Here we attempt to disambiguate these influences by using a reading level-matched design, where dyslexic children were contrasted not only with age-matched controls, but also with younger controls who read at the same level as the dyslexics. Consistent with previous reports, dyslexics showed less GMV in multiple left and right hemisphere regions, including left superior temporal sulcus when compared with age-matched controls. However, not all of these differences emerged when dyslexics were compared with controls matched on reading abilities, with only right precentral gyrus GMV surviving this second analysis. When similar analyses were performed for white matter volume, no regions emerged from both comparisons. These results indicate that the GMV differences in dyslexia reported here and in prior studies are in large part the outcome of experience (e.g., disordered reading experience) compared with controls, with only a fraction of the differences being driven by dyslexia per se.

La Esclerosis Múltiple (EM) es una enfermedad en la que la memoria de trabajo (MT) se encuentra comúnmente afectada. Estudiar la eficacia de un programa de entrenamiento en MT en pacientes de EM. 29 pacientes de EM Remitente-Recurrente fueron seleccionados para el estudio: 15 realizaron el entrenamiento en MT y 14 fueron seleccionados como grupo control. Todos los participantes fueron valorados a nivel neuropsicológico y se adquirieron imágenes de Resonancia Magnética funcional (RMf) durante la realización de la tarea 2 y 3-back (basal y post tratamiento-7 días). Los pacientes entrenados mejoraron su ejecución en 2 y 3-back (p

Using PET and H215O, we investigated the cortical areas that merge two different ways of coding space in the cerebral cortex, those concerned with the oculomotor and the somatomotor space. Normal subjects performed a visuomotor task that required the spatial coding of visual stimuli in oculomotor space and of motor responses in somatomotor space. We manipulated the mapping of oculomotor and somatomotor space by instructing subjects to respond in half of the PET scans with uncrossed hands, i.e. each hand was in the homonymous hemispace (standard oculomotor-somatomotor mapping), and in the other half with crossed hands, i.e. with the left hand in the right hemispace and the right hand in the left hemispace (nonstandard oculomotor-somatomotor mapping). Reaction times were slower for crossed hands than uncrossed hands. Crossed hands produced increases in blood flow in the precentral and postcentral gyri of the right hemisphere. Increases in blood flow in the precentral gyrus were correlated with increases in reaction time comparing the crossed-hand task with the uncrossed one, whereas the increases in blood flow in the postcentral gyrus were not. These findings suggest that the right precentral gyrus merges oculomotor and somatomotor space coding in the human brain.