Area PF Research Articles

Explorando la opinión de los especialistas españoles acerca de la utilidad de la radiómica en el área oncológica

AimTo describe the knowledge and opinion of health professionals regarding the usefulness of radiomics in oncology. MethodsA 12-question questionnaire (multiple-choice responses, Likert-type scale, and open response) was developed and sent to professionals related to diagnosis/treatment of oncological diseases (Oncology, Radiodiagnosis, Nuclear Medicine, Radiation Oncology, Hematology-Oncology, Radiophysics and Pathology). Participants were classified into two groups according to their level of training: attending physicians and residents. Results114 professionals completed the survey (54% residents, mostly from Nuclear Medicine and Radiodiagnostic specialties). Attending physicians obtained a better performance in the area pf knowledge compared to residents. Both groups of respondents agreed regarding the usefulness of radiomics to help make more accurate diagnoses and promoting the work of medical teams and the most frequent disadvantages were related to the lack of systematization in the acquisition of images and extraction of parameters, the need for the training of professionals and concern about the replacement of human work by technological tools. ConclusionsRadiomics is a novel field and the most general aspects are known by health professionals. The professionals surveyed were optimistic about the benefits provided by radiomics and other types of tools. The main problem detected was the lack of systematization in its implementation. The replacement of professionals and job loss is a concern, albeit less prevalent, and may respond to a generational phenomenon.

Exploring the opinion of Spanish medical specialists about the usefulness of radiomics in oncology

AimTo describe the knowledge and opinion of health professionals regarding the usefulness of radiomics in oncology. MethodsA 12-question questionnaire (multiple-choice responses, Likert-type scale, and open response) was developed and sent to professionals related to diagnosis/treatment of oncological diseases (Oncology, Radiodiagnosis, Nuclear Medicine, Radiation Oncology, Hematology-Oncology, Radiophysics and Pathology). Participants were classified into two groups according to their level of training: attending physicians and residents. Results114 professionals completed the survey (54% residents, mostly from Nuclear Medicine and Radiodiagnostic specialties). Attending physicians obtained a better performance in the area pf knowledge compared to residents. Both groups of respondents agreed regarding the usefulness of radiomics to help make more accurate diagnoses and promoting the work of medical teams and the most frequent disadvantages were related to the lack of systematization in the acquisition of images and extraction of parameters, the need for the training of professionals and concern about the replacement of human work by technological tools. ConclusionsRadiomics is a novel field and the most general aspects are known by health professionals. The professionals surveyed were optimistic about the benefits provided by radiomics and other types of tools. The main problem detected was the lack of systematization in its implementation. The replacement of professionals and job loss is a concern, albeit less prevalent, and may respond to a generational phenomenon.

Architecture of the inferior parietal cortex in capuchin monkey.

We studied the organization of the inferior parietal cortex (IPC) in five capuchin monkey (6 hemispheres) using cytoarchitectonic (Nissl), myeloarchitectonic (Gallyas), and immune-architectonic (SMI-32 monoclonal antibody) techniques. We partitioned the IPC into five distinct areas: PFG, PG, Opt, PFop, and PGop. Since we used parasagittal sections, we were not able to study area PF due to its far lateral position, which yielded slices that were tangential to the pial surface. Areas PFG, PG, and Opt were in the convexity close to the lateral sulcus, while PFop and PGop were positioned more posteriorly, in the opercular region of IPC. Of all the five regions, area Opt was the one most similar to its analogue in the macaque, especially as revealed with SMI-32 staining. Namely, in both primate species area Opt showed a low density of large pyramidal neurons. Additionally, the apical dendrites of these neurons were sparse and vertically orientated, resembling columns. We also found area PG to be similar: both species exhibited cell body layers with a radial arrangement. On the other hand, Nissl staining revealed area PFG to be architectonically different between New and Old-World monkeys: PFG in the capuchin showed a comparatively higher cell density than in macaques, especially in layers II and IV. These results suggest that evolution may have enabled the functional specialization of these brain regions based on behavioral demands of upper limb use. The small differences in the IPC of the two primates may be linked to interspecies variability.

The Area Prostriata may play a role in technical reasoning

Most recent research indicated how technical reasoning (TR), namely, a specific form of causal reasoning aimed at understanding the physical world, may support the development of tools and technologies of increasing complexity. We have recently identified the Area PF of the left inferior parietal lobe (PF) as a critical structural correlate of TR, as assessed by using two ad-hoc psycho-technical tests evaluating the two main aspects of TR, i.e., physical world’s understanding and visuospatial imagery. Here, we extended our findings by implementing new ad-hoc analyses of our previous data by using a whole-brain approach. Results showed that the cortical thickness (CT) of the left Area Prostriata of the visual cortex, alongside the left Area PF CT, predicts TR performance.

The cortical thickness of the area PF of the left inferior parietal cortex mediates technical-reasoning skills

Most recent research highlights how a specific form of causal understanding, namely technical reasoning, may support the increasing complexity of tools and techniques developed by humans over generations, i.e., the cumulative technological culture (CTC). Thus, investigating the neurocognitive foundations of technical reasoning is essential to comprehend the emergence of CTC in our lineage. Whereas functional neuroimaging evidence started to highlight the critical role of the area PF of the left inferior parietal cortex (IPC) in technical reasoning, no studies explored the links between the structural characteristics of such a brain region and technical reasoning skills. Therefore, in this study, we assessed participants’ technical-reasoning performance by using two ad-hoc psycho-technical tests; then, we extracted from participants’ 3 T T1-weighted magnetic-resonance brain images the cortical thickness (i.e., a volume-related measure which is associated with cognitive performance as reflecting the size, density, and arrangement of cells in a brain region) of all the IPC regions for both hemispheres. We found that the cortical thickness of the left area PF predicts participants’ technical-reasoning performance. Crucially, we reported no correlations between technical reasoning and the other IPC regions, possibly suggesting the specificity of the left area PF in generating technical knowledge. We discuss these findings from an evolutionary perspective, by speculating about how the evolution of parietal lobes may have supported the emergence of technical reasoning in our lineage.

Pantomime of tool use: looking beyond apraxia.

Pantomime has a long tradition in clinical neuropsychology of apraxia. It has been much more used by researchers and clinicians to assess tool-use disorders than real tool use. Nevertheless, it remains incompletely understood and has given rise to controversies, such as the involvement of the left inferior parietal lobe or the nature of the underlying cognitive processes. The present article offers a comprehensive framework, with the aim of specifying the neural and cognitive bases of pantomime. To do so, we conducted a series of meta-analyses of brain-lesion, neuroimaging and behavioural studies about pantomime and other related tasks (i.e. real tool use, imitation of meaningless postures and semantic knowledge). The first key finding is that the area PF (Area PF complex) within the left inferior parietal lobe is crucially involved in both pantomime and real tool use as well as in the kinematics component of pantomime. The second key finding is the absence of a well-defined neural substrate for the posture component of pantomime (both grip errors and body-part-as-tool responses). The third key finding is the role played by the intraparietal sulcus in both pantomime and imitation of meaningless postures. The fourth key finding is that the left angular gyrus seems to be critical in the production of motor actions directed towards the body. The fifth key finding is that performance on pantomime is strongly correlated with the severity of semantic deficits. Taken together, these findings invite us to offer a neurocognitive model of pantomime, which provides an integrated alternative to the two hypotheses that dominate the field: The gesture-engram hypothesis and the communicative hypothesis. More specifically, this model assumes that technical reasoning (notably the left area PF), the motor-control system (notably the intraparietal sulcus), body structural description (notably the left angular gyrus), semantic knowledge (notably the polar temporal lobes) and potentially theory of mind (notably the middle prefrontal cortex) work in concert to produce pantomime. The original features of this model open new avenues for understanding the neurocognitive bases of pantomime, emphasizing that pantomime is a communicative task that nevertheless originates in specific tool-use (not motor-related) cognitive processes.<Please insert Graphical abstract here>

On the Neurocognitive Co-Evolution of Tool Behavior and Language: Insights from the Massive Redeployment Framework.

Understanding the link between brain evolution and the evolution of distinctive features of modern human cognition is a fundamental challenge. A still unresolved question concerns the co-evolution of tool behavior (i.e., tool use or tool making) and language. The shared neurocognitive processes hypothesis suggests that the emergence of the combinatorial component of language skills within the frontal lobe/Broca's area made possible the complexification of tool-making skills. The importance of the frontal lobe/Broca's area in tool behavior is somewhat surprising with regard to the literature on neuropsychology and cognitive neuroscience, which has instead stressed the critical role of the left inferior parietal lobe. Therefore, to be complete, any version of the shared neurocognitive processes hypothesis needs to integrate the potential interactions between the frontal lobe/Broca's area and the left inferior parietal lobe as well as their co-evolution at a phylogenetic level. Here, we sought to provide the first elements of answer through the use of the massive deployment framework, which posits that evolutionarily older brain areas are deployed in more cognitive functions (i.e., they are less specific). We focused on the left parietal cortex, and particularly the left areas PF, PGI, and anterior intraparietal (AIP), which are known to be involved in tool use, language, and motor control, respectively. The deployment of each brain area in different cognitive functions was measured by conducting a meta-analysis of neuroimaging studies. Our results confirmed the pattern of specificity for each brain area and also showed that the left area PGI was far less specific than the left areas PF and AIP. From these findings, we discuss the different evolutionary scenarios depicting the potential co-evolution of the combinatorial and generative components of language and tool behavior in our lineage.

Investigating the Impact of the Missing Significant Objects in Scene Recognition Using Multivariate Pattern Analysis.

Significant objects in a scene can make a great contribution to scene recognition. Besides the three scene-selective regions: parahippocampal place area (PPA), retrosplenial complex (RSC), and occipital place area (OPA), some neuroimaging studies have shown that the lateral occipital complex (LOC) is also engaged in scene recognition processing. In this study, the multivariate pattern analysis was adopted to explore the object-scene association in scene recognition when different amounts of significant objects were masked. The scene classification only succeeded in the intact scene in the ROIs. In addition, the average signal intensity in LOC [including the lateral occipital cortex (LO) and the posterior fusiform area (pF)] decreased when there were masked objects, but such a decrease was not observed in scene-selective regions. These results suggested that LOC was sensitive to the loss of significant objects and mainly involved in scene recognition by the object-scene semantic association. The performance of the scene-selective areas may be mainly due to the fact that they responded to the change of the scene's entire attribute, such as the spatial information, when they were employed in the scene recognition processing. These findings further enrich our knowledge of the significant objects' influence on the activation pattern during the process of scene recognition.

Technition: When Tools Come Out of the Closet

People are ambivalently enthusiastic and anxious about how far technology can go. Therefore, understanding the neurocognitive bases of the human technical mind should be a major topic of the cognitive sciences. Surprisingly, however, scientists are not interested in this topic or address it only marginally in other mainstream domains (e.g., motor control, action observation, social cognition). In fact, this lack of interest may hinder our understanding of the necessary neurocognitive skills underlying our appetence for transforming our physical environment. Here, we develop the thesis that our technical mind originates in perhaps uniquely human neurocognitive skills, namely, technical-reasoning skills involving the area PF within the left inferior parietal lobe. This thesis creates an epistemological rupture with the state of the art that justifies the emergence of a new field in the cognitive sciences (i.e., technition) dedicated to the intelligence hidden behind tools and other forms of technologies, including constructions.

To Watch is to Work: a Review of NeuroImaging Data on Tool Use Observation Network.

Since the discovery of mirror neurons in the 1990s, many neuroimaging studies have tackled the issue of action observation with the aim of unravelling a putative homolog human system. However, these studies do not distinguish between non-tool-use versus tool-use actions, implying that a common brain network is systematically involved in the observation of any action. Here we provide evidence for a brain network dedicated to tool-use action observation, called the tool-use observation network, mostly situated in the left hemisphere, and distinct from the non-tool-use action observation network. Areas specific for tool-use action observation are the left cytoarchitectonic area PF within the left inferior parietal lobe and the left inferior frontal gyrus. The neural correlates associated with the observation of tool-use reported here offer new insights into the neurocognitive bases of action observation and tool use, as well as addressing more fundamental issues on the origins of specifically human phenomena such as cumulative technological evolution.

Thalamic Inputs to Posterior Parietal Cortical Areas Involved in Skilled Forelimb Movement and Tool Use in the Capuchin Monkey.

The posterior parietal cortex (PPC) is a central hub for the primate forebrain networks that control skilled manual behavior, including tool use. Here, we quantified and compared the sources of thalamic input to electrophysiologically-identified hand/forearm-related regions of several PPC areas, namely areas 5v, AIP, PFG, and PF, of the capuchin monkey (Sapajus sp). We found that these areas receive most of their thalamic connections from the Anterior Pulvinar (PuA), Lateral Posterior (LP) and Medial Pulvinar (PuM) nuclei. Each PPC area receives a specific combination of projections from these nuclei, and fewer additional projections from other nuclei. Moreover, retrograde labeling of the cells innervating different PPC areas revealed substantial intermingling of these cells within the thalamus. Differences in thalamic input may contribute to the different functional properties displayed by the PPC areas. Furthermore, the observed innervation of functionally-related PPC domains from partly intermingled thalamic cell populations accords with the notion that higher-order thalamic inputs may dynamically regulate functional connectivity between cortical areas.

NTUm-based optimization of heat or heat pump driven liquid desiccant dehumidification systems regenerated by fresh air or return air

Liquid desiccant (LD) dehumidification systems have received significant attention in recent years owing to their effectiveness in humidity control and great potential for energy saving in buildings. The optimization of these systems, considering the relevant influencing factors, is thus an important research purpose. This paper focuses on the optimization pf area distribution among the packing towers, under a fixed total area, in the liquid desiccant dehumidification systems. Two typical LD dehumidification systems are analyzed and optimized. One system is regenerated by fresh air and the other system is regenerated by return air, with total heat recovery and the dehumidification modules. The input heat for the heat driven pattern and the input work for the heat pump driven pattern are adopted as the optimizing indexes. It is indicated that for the first system, the square ratio of the optimum NTUm of the dehumidifier to that of the regenerator is equal to the ratio of the enthalpy difference between the fresh air and supply air to that between the fresh air and exhaust air. For the second system, the optimum NTUm of the total heat recovery module accounts for about 30% of the total NTUm. The heat-cold offset takes a great proportion of the input heat, and the NTUm distribution development based on the optimum input work with the heat pump driven pattern is consistent with that based on the optimum input heat with the heat driven pattern. Therefore the optimization of input heat is important for LD systems and can be the representative criterion for their NTUm-based optimization.

P 11 Towards a human vestibular cortex – Manifold confounders hamper the delineation of vestibular responses in functional neuroimaging

Aim Galvanic vestibular stimulation (GVS) allows for robust vestibular responses and is therefore the gold standard in neuroimaging studies focusing on the central vestibular system. Nevertheless, there are several confounding side-effects which hinder the delineation of pure vestibular responses. Besides stimulating vestibular hair cells and afferent fibers [1] , mastoidal GVS also evokes somatosensory, vagal and nociceptive responses. Furthermore, GVS induces reflectory head movements leading to motion artefacts. Aim of our fMRI study was to assess and control for the impact of these confounders by means of local anaesthesia, optimized head fixation, and a sham-GVS stimulation with different current intensities. Methods We examined 44 right-handed healthy subjects (21 F; mean age 28 years) in three sessions (interval length between session > 24 h) with different conditions: GVS with 3.5 mA with/without local anaesthesia, sham-GVS with 3.5 mA/1 mA, and GVS with/without head fixation (headfixation system: Pearltec, Switzerland). Structural and functional images were obtained in a clinical 3T scanner (Siemens Magnetom Verio) with a 32-channel head coil. The protocol included a GVS stimulation session consisting of a T2*-weighted EPI sequence (TR 2s, 31 ascending slices, 3 mm in-plane resolution, slice thickness 3.5 mm), a MPRAGE sequence, and a resting-state session. Data analysis was performed using SPM 12 (Version 6407 Wellcome Department of Imaging Neuroscience, UK) and the motion fingerprint toolbox (Wilke, Neuroimage 2012) after standard preprocessing using DARTEL-based normalization. Results were considered significant at FDR p 0.05 (corrected at cluster level). Results Pain perception during GVS decreased significantly after local anesthesia (NRS-11 reduction from 4.5 to 1.7, Wilcoxon signed-rank test, Z = −3.79, p = 0.00). GVS with lidocaine evoked responses in the vestibular network, predominantly in right OP2 and the medial cingulate cortex bilaterally, which were absent during sham stimulation. Without anesthesia, confluent activation cluster were found in anterior and posterior insula-opercular regions. Activation of the insula was also shown bilaterally during sham-GVS, with a predominant effect in area OP1 and area PF with a current intensity of 3.5 mA. Sham-GVS with 1 mA led to bilateral responses in area Fp1, the precentral gyrus and the left posterior cingulum. Motion finger print analysis in GVS with and without head fixation revealed head motion predominantly in the roll plane, leading to inter-slice motion artefacts in temporo-parietal-opercular regions. These artefacts were eliminated using a new head fixation system. Conclusion In this fMRI study, we evaluated and minimized the effects of several confounders in GVS. Head motion artefacts as well as nociceptive and somatosensory responses may hinder the localization of actual vestibular response patterns, particularly in the insula and parietal operculum. Our results highlight the importance of controlling for these side-effects and lead the way towards a precise definition of the human vestibular cortical network.

Development of rostral inferior parietal lobule area functional connectivity from late childhood to early adulthood

Although the mirror neuron system (MNS) has been extensively studied in monkeys and adult humans, very little is known about its development. Previous studies suggest that the MNS is present by infancy and that the brain and MNS-related cognitive abilities (such as language, empathy, and imitation learning) continue to develop after childhood. In humans, the PFt area of the inferior parietal lobule (IPL) seems to particularly correlate with the functional properties of the PF area in primates, which contains mirror neurons. However, little is known about the functional connectivity (FC) of the PFt area with other brain areas and whether these networks change over time. Here, we investigated the FC development of the PFt area-based network in 59 healthy subjects aged 7–26 years at resting-state to study brain development from late childhood through adolescence to early adulthood. The bilateral PFt showed similar core FC networks, which included the frontal lobe, the cingulate gyri, the insula, the somatosensory cortex, the precuneus, the superior and inferior parietal lobules, the temporal lobe, and the cerebellum posterior lobes. Furthermore, the FC between the left PFt and the left IPL exhibited a significantly positive correlation with age, and the FC between the left PFt and the right postcentral gyrus exhibited a significantly negative correlation with age. In addition, the FC between the right PFt and the right putamen exhibited a significantly negative correlation with age. Our findings suggest that the PFt area-based network develops and is reorganized with age.

RELIABILITY OF THE FATIGUE SEVERITY SCALE IN CIRRHOTIC AND CORRELATION WITH DEPRESSION AND QUALITY OF LIFE: preliminary assessment.

Fatigue is a common complaint in patients with liver disease and may be considered a disabling symptom, affecting their quality of life and mental health. The Brazilian version of the Fatigue Severity Scale showed sensitivity to assess fatigue in some populations, but has not been tested in cirrhotic individuals. The aim of this study was to evaluate the reliability of the Fatigue Severity Scale and association with depression and quality of life in patients with liver cirrhosis. A prospective cohort study where the same interviewer applied to 25 patients Fatigue Severity Scale questionnaires, Brazilian version of the Beck Depression Inventory II (BDI- II) and Brazilian version of the Short Form Health Survey II (SF-36 v.II). Evaluating the reliability of the Fatigue Severity Scale through internal consistency and reproducibility was conducted. Statistical analysis showed strong internal consistency (Cronbach's alpha = 0.917) and intraobserver reproducibility test, there was no significant difference between both moments (P=0.828). Fatigue Severity Scale was significantly associated with BDI- II (r=0.478; P=0.016) and quality of life in areas PF (r=-0.484; P=0.014), BP (r=-0.402; P=0.046) and GH (r=-0.406; P=0.044) and SF (r=-0.520; P=0.008). The Fatigue Severity Scale showed satisfactory reliability in evaluation of fatigue in cirrhotic and can be used as a tool for this purpose. Fatigue is related to depression and quality of life in the physical aspects domains, pain, general health and social aspects.

Exogenous features versus prior experiences modulate different subregions of the right IPL during episodic memory retrieval.

The fractionation view holds that distinct cognitive operations are mediated by subregions of the inferior parietal lobule (IPL). Within IPL, we hypothesised that retrieval-related activity in different parts of the right supramarginal gyrus (rSMG) may be modulated differentially by information acquired via different combinations of attention signals at encoding. We had two groups of participants watch a 42-min TV episode and, after a 24-hr delay, perform a temporal-order judgment task during fMRI. Each retrieval trial comprised three images presented sequentially, requiring participants to judge the temporal order between the first and last images while ignoring the second image (“distractor”). We manipulated the bottom-up factor by presenting distractors that were extracted from either an event-boundary or a non-boundary of the movie. The top-down factor was manipulated by instructing one group perform a segmentation task reporting the event-boundaries at encoding, while the other group watched the movie passively. Across groups, we found that the stimulus-related factor modulated retrieval activation in the anterior rSMG (areas PFt and PFop), whereas the goal-related influence of prior segmentation interacted with this effect in the middle rSMG (area PF), demonstrating IPL segregation during retrieval as a function of prior bottom-up vs. top-down attention signals.

Cortical and thalamic projections to cytoarchitectural areas 6Va and 8C of the marmoset monkey: connectionally distinct subdivisions of the lateral premotor cortex.

We studied the afferent connections of two cytoarchitectural subdivisions of the caudolateral frontal cortex, areas 6Va and 8C, in marmoset monkeys. These areas received connections from the same set of thalamic nuclei, including main inputs from the ventral lateral and ventral anterior complexes, but differed in their patterns of corticocortical connections. Areas 8C and 6Va had reciprocal interconnections, and received similar proportions of afferents from premotor areas 6M and 6DC, and from the prefrontal cortex. However, area 8C received stronger inputs from frontal areas that have been implicated in oculomotor functions, whereas area 6Va received stronger projections from the primary motor area. Somatosensory projections to area 6Va were generally stronger than those to area 8C, and originated from several areas; in contrast, only the second somatosensory area (S2) sent major inputs to area 8C. Finally, although both 6Va and 8C received major inputs from the rostral posterior parietal cortex (putative homologs of areas PE, PF, and PFG), area 8C also received a variety of smaller connections from posterior midline, caudal posterior parietal, and extrastriate areas. Statistical analyses revealed that the pattern of connections of area 8C is more akin to that characterizing a premotor area, rather than a prefrontal area. We conclude that cytoarchitectural area 6Va in the marmoset is similar to ventral premotor areas identified in other simian primates, and that area 8C corresponds to a specialized subdivision of the caudal premotor complex where visual information for the guidance of movements is likely to be emphasized.

Importance of pericardial fat in the formation of complex fractionated atrial electrogram region in atrial fibrillation

Background/ObjectivesPericardial fat (PF) and complex fractionated atrial electrogram (CFAE) are both associated with atrial fibrillation (AF). Therefore, we examined the relation between PF and CFAE area in AF. MethodsThe study population included 120 control patients without AF and 120 patients with AF (80 paroxysmal AF and 40 persistent AF) who underwent catheter ablation. Total cardiac PF volume, representing all adipose tissue within the pericardial sac, was measured by contrast-enhanced computed tomography. The location and distribution of CFAE region were identified by left atrial endocardial mapping using a three-dimensional mapping system. We analyzed the significance of total cardiac PF volume and total area of CFAE region on AF, persistence of AF from paroxysmal to persistent form, and the relation between total cardiac PF volume and total CFAE area. We also evaluated the regional distribution of PF volume and CFAE area in five areas of the left atrium (LA). ResultsTotal cardiac PF volume correlated with AF (odds ratio [OR]: 1.024, p<0.001). Total cardiac PF volume and total CFAE area were both independently associated with persistence of AF (OR: 1.018, p=0.018, OR: 1.144, p=0.002, respectively). Multivariate linear regression analysis identified total cardiac PF volume as a significant and independent determinant of total CFAE area (r=0.488, p<0.001). Furthermore, regional PF volume correlated with local CFAE area in an each LA area. ConclusionsPF volume correlated significantly with CFAE area in patients with AF. This finding suggests that PF is directly related to the progression of CFAE area and promotes the pathogenic process of AF.

Functional Magnetic Resonance Imaging Connectivity Analyses Reveal Efference-Copy to Primary Somatosensory Area, BA2

Some theories of motor control suggest efference-copies of motor commands reach somatosensory cortices. Here we used functional magnetic resonance imaging to test these models. We varied the amount of efference-copy signal by making participants squeeze a soft material either actively or passively. We found electromyographical recordings, an efference-copy proxy, to predict activity in primary somatosensory regions, in particular Brodmann Area (BA) 2. Partial correlation analyses confirmed that brain activity in cortical structures associated with motor control (premotor and supplementary motor cortices, the parietal area PF and the cerebellum) predicts brain activity in BA2 without being entirely mediated by activity in early somatosensory (BA3b) cortex. Our study therefore provides valuable empirical evidence for efference-copy models of motor control, and shows that signals in BA2 can indeed reflect an input from motor cortices and suggests that we should interpret activations in BA2 as evidence for somatosensory-motor rather than somatosensory coding alone.

Dissociations between spatial-attentional processes within parietal cortex: insights from hybrid spatial cueing and change detection paradigms

Spatial cueing has been used by many different groups under multiple forms to study spatial attention processes. We will present evidence obtained in brain-damaged patients and healthy volunteers using a variant of this paradigm, the hybrid spatial cueing paradigm, which, besides single-target trials with valid and invalid cues, also contains trials where a target is accompanied by a contralateral competing stimulus (competition trials). This allows one to study invalidity-related processes and selection between competing stimuli within the same paradigm. In brain-damaged patients, lesions confined to the intraparietal sulcus result in contralesional attentional deficits, both during competition and invalid trials, according to a pattern that does not differ from that observed following inferior parietal lesions. In healthy volunteers, however, selection between competing stimuli and invalidity-related processes are partially dissociable, the former relying mainly on cytoarchitectonic areas hIP1-3 in the intraparietal sulcus, the latter on cytoarchitectonic area PF in the right inferior parietal lobule. The activity profile in more posterior inferior parietal areas PFm and PGa, does not distinguish between both types of trials. The functional account for right PF and adjacent areas is further constrained by the activity profile observed during other experimental paradigms. In a change detection task with variable target and distracter set size, for example, these inferior parietal areas show highest activity when the stimulus array consists of only one single target, while the intraparietal sulcus show increased activity as the array contains more targets and distracters. Together, these findings lead us to the hypothesis that right PF functions as a target singleton detector, which is activated when a target stands out from the background, referring both to the temporal background (expectancy) and the momentaneous background (stimulus-driven saliency).