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At least 1,621 records · Page 90Linked to original sources
PubMed1997

Transrectal ultrasound versus digital rectal examination for the staging of carcinoma of the prostate: results of a prospective, multi-institutional trial.

PURPOSE: We determined the accuracy of transrectal ultrasonography versus digital rectal examination in staging the local extent of biopsy proved carcinoma of the prostate. MATERIALS AND METHODS: A National Institutes of Health funded network was developed to perform prospective, multi-institutional trials. A total of 386 patients judged by the investigators to be candidates for radical prostatectomy underwent transrectal ultrasonography with recording of data according to a numerical analog for construction of receiver operating characteristic curves. The results of digital rectal examination were similarly recorded. After radical prostatectomy whole mount histology was performed on all surgical specimens, and pathological findings were correlated with preoperative transrectal ultrasound and digital rectal examination results. RESULTS: The calculated area under the curve for transrectal ultrasound in predicting extracapsular tumor extension was 0.69 compared to 0.72 for digital rectal examination (p = 0.64), while that for predicting seminal vesicle invasion was 0.74 and 0.69, respectively (p = 0.36). There was a nonstatistically significant trend for improved accuracy of both examinations as tumor volume increased. Transrectal ultrasound was more accurate for staging posterior cancers than for those in the anterior portion of the prostate. CONCLUSIONS: Neither transrectal ultrasound nor digital rectal examination proved to be superior to each other for staging the local extent of prostate cancer. No imaging modality or examination that depends on gross architectural changes is likely to have a high degree of accuracy in detecting microscopic extension of extracapsular tumor frequently observed in radical prostatectomy specimens.

Adenocarcinoma↗
PubMed2000

Gastric lymphography and detection of sentinel nodes.

The lymphatic drainage system of the stomach was studied using lymphography with various dyes, and several major routes have been shown. Gastric lymph channels are multidirectional and form complex networks. We conducted a retrospective study to know the first site of metastasis from small gastric cancers by examining 89 cases with only one lymph node metastasis. The perigastric nodal area close to the primary tumor was the first site of metastasis in only 62% of the cases. N2 metastasis without N1 involvement was seen in 13%. In order to identify sentinel nodes for local resection of gastric cancer, a novel method needs to be developed.

Carbon↗
PubMed1994

Dynamics of local neuronal networks: control parameters and state bifurcations in epileptogenesis.

The aim of this overview is to present evidence that local neuronal networks (LNNs) are functionally organized in such a way that they behave as dynamic non-linear systems that can exhibit multiple types of attractor and can present bifurcations between different attractors, depending on control parameters. To begin with, some of the theoretical concepts of non-linear dynamics and chaos are briefly presented. As a case study, we described the CA1 area of the hippocampus and the changes that the corresponding LNNs undergo during kindling epileptogenesis. During epileptic seizures, evidence exists for the presence of low-dimensional chaos, since the correlation dimension estimated from the corresponding EEG signals decreases dramatically from a large value, characteristic of the resting state, to a low value typical of deterministic chaos. We propose that, among other things, an important control parameter of the dynamics of this brain area is the balance between excitatory (E) and inhibitory (I) processes. We assume that this balance can be experimentally estimated by using a paired-pulse paradigm. Accordingly, we demonstrate that the paired-pulse response changes during kindling epileptogenesis in the sense that the E/I ratio increases in the course of the establishment of a kindled epileptogenic focus. This change in E/I leads to a shift in the operating point of the LNN moving it close to a bifurcation where a rapid state change takes place. In this way, the LNN dynamics can change more readily to the basin of attraction of a chaotic attractor than under normal conditions. This is in essence what makes the behavior of the LNN more sensitive to tetanus, and predicts the facilitated occurrence of epileptic seizures during kindling.

Animals↗
PubMed1995

The rab7 GTPase resides on a vesicular compartment connected to lysosomes.

Rab GTPases belong to the Ras GTPase superfamily and are key regulators of membrane traffic. Among them, rab7 has been localized on late endosomes of NRK cells but its function remains unknown. In order to investigate its role, we generated stable HeLa cell lines that express either wild type or a GTPase-defective mutant of rab7 in an inducible manner. A morphological analysis of the intracellular localization of these proteins was performed by confocal laser microscopy. Here we show that, in HeLa cells, rab7 is present on a vesicular compartment that extends from the perinuclear area to the cell periphery and shows only a partial colocalization with the cation-independent mannose 6-phosphate receptor, a marker for late endosomes. The topology of this compartment is dependent on the microtubule network since nocodazole treatment results in its scattering throughout the cytoplasm. In addition, we observed that, in contrast to the wild-type protein, a rab7 mutant with a reduced GTPase activity is in part associated with lysosomal membranes. This observation was confirmed by subcellular fractionation in a Percoll gradient. Our data implicate rab7 as the first GTPase functioning on terminal endocytic structures in mammalian cells.

Animals↗
PubMed2002

Local generation of fast ripples in epileptic brain.

Aperiodic high-frequency oscillations (>100 Hz) reflect a short-term synchronization of neuronal electrical activity. It has been shown in the epileptic brain that spontaneous oscillations in the frequency range of 250-600 Hz reflect action potential population bursts of synchronously discharging neuronal clusters. These oscillations occur in the early stages of epileptogenesis in areas adjacent to the brain lesion and may trigger the formation of seizure-generating neuronal networks. We studied the extent of the area generating oscillations in the frequency range of 250-600 Hz [fast ripples (FRs)] in intrahippocampal kainic acid-treated rats with spontaneous seizures, by analyzing voltage versus depth profiles of FRs in hippocampal and parahippocampal areas in freely moving animals and by spatial mapping in hippocampal slice preparations in vitro. The strength of inhibition was compared in areas with and without FRs using a paired-pulse paradigm. The extent of the areas generating FRs did not exceed 1 mm(3). The areas generating FRs became broader after the application of the GABA(A) receptor antagonist bicuculline. Paired-pulse fast inhibition at 15-30 msec intervals was similar in areas generating FRs and areas not generating FRs. Our data illustrate that hypothesized clusters of highly interconnected neurons are capable of overcoming interneuron feedback inhibition, resulting in generation of epileptiform bursts, eventually leading to seizure activity.

Action Potentials↗
PubMed2001

A biologically motivated solution to the cocktail party problem.

We present a new approach to the cocktail party problem that uses a cortronic artificial neural network architecture (Hecht-Nielsen, 1998) as the front end of a speech processing system. Our approach is novel in three important respects. First, our method assumes and exploits detailed knowledge of the signals we wish to attend to in the cocktail party environment. Second, our goal is to provide preprocessing in advance of a pattern recognition system rather than to separate one or more of the mixed sources explicitly. Third, the neural network model we employ is more biologically feasible than are most other approaches to the cocktail party problem. Although the focus here is on the cocktail party problem, the method presented in this study can be applied to other areas of information processing.

Artificial Intelligence↗
PubMedDate not supplied

Cortical networks for visual reaching: physiological and anatomical organization of frontal and parietal lobe arm regions.

The functional and structural properties of the dorsolateral frontal lobe and posterior parietal proximal arm representations were studied in macaque monkeys. Physiological mapping of primary motor (MI), dorsal premotor (PMd), and posterior parietal (area 5) cortices was performed in behaving monkeys trained in an instructed-delay reaching task. The parietofrontal corticocortical connectivities of these same areas were subsequently examined anatomically by means of retrograde tracing techniques. Signal-, set-, movement-, and position-related directional neuronal activities were distributed nonuniformly within the task-related areas in both frontal and parietal cortices. Within the frontal lobe, moving caudally from PMd to the MI, the activity that signals for the visuo-spatial events leading to target localization decreased, while the activity more directly linked to movement generation increased. Physiological recordings in the superior parietal lobule revealed a gradient-like distribution of functional properties similar to that observed in the frontal lobe. Signal- and set-related activities were encountered more frequently in the intermediate and ventral part of the medial bank of the intraparietal sulcus (IPS), in area MIP. Movement-and position-related activities were distributed more uniformly within the superior parietal lobule (SPL), in both dorsal area 5 and in MIP. Frontal and parietal regions sharing similar functional properties were preferentially connected through their association pathways. As a result of this study, area MIP, and possibly areas MDP and 7m as well, emerge as the parietal nodes by which visual information may be relayed to the frontal lobe arm region. These parietal and frontal areas, along with their association connections, represent a potential cortical network for visual reaching. The architecture of this network is ideal for coding reaching as the result of a combination between visual and somatic information.

Animals↗
PubMedDate not supplied

Immunohistochemical studies on cholecystokinin (CCK)-immunoreactive neurons in the rat using sequence specific antisera and with special reference to the caudate nucleus and primary sensory neurons.

In the present immunohistochemical study the occurrence and distribution of CCK-immunoreactive neurons were analyzed in the brain, spinal cord and sensory ganglia using sequence specific antisera. Thus, antibodies directed towards the C-terminal portion of CCK-33, to the N-terminal portion of CCK-8 and to the mid portion of CCK-33 as well as monoclonal antibodies were used. For comparison antisera raised against calcitonin gene-related peptide (CGRP), tyrosine hydroxylase (TH) and 5-hydroxytryptamine (5-HT) were used. Untreated, colchicine treated, 6-hydroxydopamine (6-OH-DA) treated and ibotenic acid treated rats were analyzed. The results indicate that most CCK systems in the rat central nervous system contain genuine CCK. These include, for example, the hippocampal formation, the hypothalamus, several subcortical forebrain areas, the ventral mesencephalon, nucleus tractus solitarii, some neurons in the ventral medulla oblongata as well as local and possibly descending neurons in the spinal cord. An exception was primary sensory neurons in which CCK-like immunoreactivity (LI) could only be demonstrated with C-terminally directed antisera and probably represents cross-reactivity with CGRP or a similar peptide. The central branches of such primary afferents were found both in the dorsal vagal complex, in the spinal trigeminal nucleus and in the dorsal horn of the spinal cord. Special attention was focused on CCK-LI in mesencephalic dopamine neurons and in their projection areas including nucleus accumbens, tuberculum olfactorium and particularly the caudate nucleus. In the latter structure CCK-LI exhibited a heterogenous pattern probably representing fibres of different types and origin. Thus, CCK-LI coexists with dopamine in two anatomically and morphologically distinguishable systems, one located in the periventricular area, increasing in size in the caudal direction to occupy most of the cauda, and a second system consisting of very fine dots in the medial half of the caudate nucleus. These two fibre types disappeared after 6-OH-DA treatment. A third system consisted of strongly fluorescent patches distributed at all levels of the caudate nucleus, mainly in its medial half. A diffuse, weakly fluorescent network of CCK-positive fibres was also found over the entire caudate nucleus. The latter two systems did not disappear after 6-OH-DA. Finally, local CCK-positive cell bodies were seen in small numbers, mainly in the ventral aspects of the caudate nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2001

Vascular fibrosis and calcification in the hippocampus in aging, Alzheimer disease, and Down syndrome.

Study of the hippocampal formation of 82 subjects, including 25 control subjects from 33 to 83 years of age, 34 subjects with Alzheimer disease (AD) from 65 to 89 years of age, and 23 subjects with Down syndrome (DS) from 33 to 72 years of age, revealed hippocampal vasculopathy with fibrosis and calcification (VFC) in 40% of control, 59% of AD, and 4% of DS subjects. VFC starts in the precapillaries/capillaries in the molecular layer of the dentate gyrus (DG) and expands to the granule cell and polymorphic cell layer of the DG, and to the stratum lacunosum/molecular in the CA1 sector. Vasculopathy spreads from the tail to the body and, in a few cases, to the head of the hippocampal formation. Light and electron microscopy reveal thickening of the vascular wall with fibrosis, calcification, and enforcement of the astrocyte interface with vessels with anchorage densities associated with hemidesmosome-like structures. In moderately and severely affected cases, fragmentation and removal of calcified and occluded vessels result in local reduction of vascular network. In two AD subjects, severe vascular calcification extending from the tail to the head of the hippocampal formation was associated with loss of almost all neurons in the CA1 sector and in the subiculum proper, corresponding to hippocampal sclerosis. The topography of affected vessels and the patterns of neuronal loss reflect the middle hippocampal artery distribution with its precapillary/capillary network. The similar prevalence of vasculopathy in the AD group and in the age-matched control group, and the presence of hippocampal VFC in only one subject in the DS cohort, 96% of which is affected by Alzheimer-type pathology, oppose the link between AD and this form of vasculopathy. However, severe VFC affects the pattern of AD pathology locally by deletion of neurofibrillary degeneration and beta-amyloidosis in the CA1 sector, subiculum proper, and the molecular layer of the dentate gyrus. Hippocampal VFC appears to be a form of vascular pathology with a unique predilection for the middle hippocampal artery and corresponding capillary network, which results in patchy neuronal loss in moderately affected subjects and in almost total neuronal loss in the area of impaired blood supply in severely affected subjects. These observations suggest an etiologic link between hippocampal VFC and hippocampal sclerosis.

Adult↗
PubMed1985

Bone marrow findings in systemic mastocytosis.

The neoplastic proliferation of tissue mast cells constitutes a group of rare diseases that have localized and systemic variants. The cytologic (n = 7) and histologic (n = 38) findings in bone marrow from a total of 45 patients with systemic mastocytosis were evaluated. Three distinct histologic patterns of marrow involvement were distinguished. In 21 cases a patchy or focal infiltration pattern was encountered. Mast cell aggregates were located predominantly in peritrabecular and perivascular areas. The adjacent trabeculae were thickened. A dense network of reticulin fibers and foci of lymphocytes accompanied the mast cell infiltrates. Increased numbers of eosinophils frequently demarcated the mast cell infiltrates from the surrounding tissue. In the noninfiltrated marrow areas hematopoiesis and the distribution of fat cells appeared to be normal. This histologic pattern, designated type 1, was observed exclusively in patients showing primary involvement of the skin, indistinguishable from urticaria pigmentosa. In 14 additional cases peritrabecular and perivascular sheets of mast cells, with concomitant fibrosis and osteosclerosis, were also present. Unlike the findings in type 1, however, the noninfiltrated marrow areas showed marked reductions in fat cell content and markedly increased granulocytopoiesis or increased numbers of blast cells (infiltration pattern type 2). On the basis of the hematologic and clinical findings, chronic myeloid leukemia was diagnosed in six of these cases, myelomonocytic leukemia in three cases, and acute myeloid leukemia in two cases. The bone marrow of three patients was diffusely infiltrated by atypical mast cells, leading to marked hypoplasia of fat cells and blood cell precursors. These histologic features were identified as infiltration pattern type 3. The diagnosis of mast cell leukemia was confirmed in all three cases by the presence of numerous mast cells in the blood. The prognosis for patients with the type 1 marrow infiltration pattern and primary skin involvement was favorable (actuarial survival rate five years after diagnosis, 0.75). This variant was called benign systemic mastocytosis. Primary skin involvement did not occur in the patients with type 2 or 3 infiltration patterns. The prognosis for these patients was poor (actuarial survival five years after diagnosis, 0.17 for type 2 and 0.00 for type 3). These two forms were accordingly designated malignant systemic mastocytosis.

Adult↗
PubMed2003

Hedgerow planting analysed as a social system--interaction between farmers and other actors in Denmark.

In a number of European countries, including Denmark, the practice of planting hedgerows has a long tradition, and hedgerows form significant structures of semi-natural elements in a matrix of arable land. In Denmark an institutionalised framework has developed in relation to a subsidy scheme encouraging farmers to plant hedgerows. This article analyses the planting practice as a social system; giving emphasis to the interactions between actors and how this affects the current planting activity. Combining an overall description of the nationwide network with a detailed case study in Jutland, Denmark enables an understanding of how the local planting practice is influenced by the local context and the nationwide network, and at the same time contributes to the reproduction of the entire network. It is concluded that the planting activity is characterised by routines, professionalism and division of labour. The local actors involved perceive the activity as a success, and do not question current practise. However, the actors are not aware of the potential consequences of the planting practice at the landscape scale. Even though hedgerows are planted through so-called planting associations related to defined local areas the placement of hedgerows is not co-ordinated and evaluated at a landscape scale. In addition, the composition of hedgerows is standardised at a national level, and the individual farmer makes few adjustments. Thus, the sense of local landscape identity may become blurred. The increasing public attention towards a multiplicity of functions in the agricultural landscape implies further development of the potential positive landscape effects of hedgerows in a local context. This may induce changes in the relationships between actors and eventually the planting practice.

Agriculture↗
PubMed2006

Packing, flipping, and buckling transitions in compressed monolayers of ellipsoidal latex particles.

The behavior of monolayers of monodisperse prolate ellipsoidal latex particles with the same surface chemistry but varying aspect ratio has been studied experimentally. Particle monolayers at an air-water interface were subjected to compression in a Langmuir trough. When surface pressure measurements and microscopy observations were combined, possible structural transitions were evaluated. Ellipsoids of a sufficiently large aspect ratio display a less abrupt increase in the compression isotherms than spherical particles. Microscopic observations reveal that a sequence of transitions is responsible for this more gradual increase of the surface pressure. When a percolating aggregate network is used as the starting point, locally ordered regions appear progressively. When it reaches a certain surface pressure, the system "jams", and in-plane rearrangements are no longer possible at this point. A highly localized yielding of the particle network is observed. The compressional stress is relieved by flipping the ellipsoids into an upright position and by expelling particles from the monolayer. The latter does not occur for spherical particles with similar dimensions and surface chemistry. In the final stage of compression, buckling of the monolayer as a whole was observed. The effect of aspect ratio on the pressure area isotherms and on the obtained percolation and packing thresholds was quantified.

Colloids↗
PubMed2006

Communities' awareness, perception and participation in the Community-Based Medical Education of the University of Maiduguri.

BACKGROUND: Community-based medical education (CBME) is no longer a new innovation in medical education since the establishment of The Network: Towards Unity for Health (The Network: TUFH) 25 years ago. The CBME of the University of Maiduguri medical college is 14 years old and has never been assessed in terms of the population it serves. The study was conducted to determine the level of awareness, perception, and participation of the communities in CBME. METHODS: A cross-sectional survey was carried out in 11 village units of three Local Government Areas (LGAs) using a 14-item structured questionnaire administered to adults in randomly selected households. The questionnaire was based on guide questions used for focus group discussions held earlier with community leaders. RESULTS: Awareness of students' visits among respondents was 73.7%. Knowledge of the frequency of presence of the students in the communities was 72.2%. "To examine and treat" (33.6%) and "to ask questions" (16.6%) were the most prominent reasons given for the visits. The majority of respondents perceived the visits as beneficial (72.2%). More frequent visits were requested by 54.4% of the respondents. The communities were willing to be more accessible and felt that the LGAs should provide more logistic support to the program. DISCUSSION: This study revealed that communities were aware of students' visits and knew reasons for the visits, thought visits were beneficial, and were willing to provide more support for these visits.

Adult↗
PubMed1987

Skin reactivity to mycobacterial antigens in children living in an area of Mycobacterium xenopi endemicity.

Intradermal skin tests with a 2TU dose of PPD-RT 23 prepared from M. tuberculosis and 0.1 ug/0.1 ml of PPD-RS 631 from M. xenopi were simultaneously carried out in 378 7-year-old children from two localities in North-Bohemian region's capital Ustí n. Lab., a focus of M. xenopi endemicity repeatedly confirmed since its disclosure in 1980 by positive M. xenopi isolations from humans and public water supply network. A further group 157 children serving as controls was from Prague district 4 where no presence of M. xenopi strains was ever recorded. All of these children had received routine immunization at birth with Czech BCG vaccine. The children from the two endemic localities were found to give a positive 6 mm or greater reaction to M. xenopi mycobacterin in 43.3% and 22.3%, to human tuberculin in 12.8% and 12.6%, respectively. The frequency histogram clearly separated a group of reactors with 8-18 mm indurations from a group of nonreactors showing a skin induration of 4-8 mm. The higher reactivity of this exposed child population was also reflected in a larger proportion of reactions greater to M. xenopi PPD than to human tuberculin antigen: the reactions greater by 1-5 mm accounted, respectively, for 25.1% and 20.6%, reactions greater by 6 mm or more for 23.7% and 15.9%. Among a group of children from Prague district 4, 6.4% had medium-sized and 3.8% large-sized reactions to M. xenopi antigen; the proportion of reactions greater to M. xenopi antigen than to human tuberculin accounted for only 5.1%, reactions greater to tuberculin than to sensitin were here in slight predominance. The evidenced skin sensitization to M. xenopi mycobacterin is suggested to result from the different degrees of exposure to infection by environmental mycobacteria.

Antigens, Bacterial↗
PubMed1980

[Construction of the microcirculatory bed of palatine salivary glands of rats].

Owing to multilayer graphic reconstruction, it was possible to state that resistance and capacitance microvessels of the palatal salivary glands are localized within the lamina propria of the palatal mucous membrane. The structural principle of blood transport and distribution is performed by a closed arteriolar system in which separate modules are distinct. In an individual module area there are tightly packed 5--6 glandular lobes, 1 or 2 of them are not connected with the gland which is completely within the limits of the module. The network of the canals delivering and distributing blood among the modules has a concentric-radial form. Every precapillary arteriole, passing in interlobular connective tissue layer towards the center--the collecting vein--delivers blood to two halves of the adjoining lobes. At various levels of organization of the vascular microcirculatory bed in the rat palatal salivary gland, canals with a predominant blood flow are revealed and functional appraisal for each is given. The palatal salivary gland lobe is noted to correspond most fully to our idea of the elementary autonomic secretory unit.

Animals↗
PubMed1997

Morphological aspects of the median eminence--place of accumulation and secretion of regulatory neurohormones and neuropeptides.

The median eminence (ME) is a small brain area forming both the structural and functional bridge between the hypothalamus and the hypophysis. It is supplied by a variety of neurohormones and neuropeptides which are delivered to the ME by different hypothalamic and extrahypothalamic pathways. These biologically active substances may act in the ME locally influencing the activity of secretion of the neighbouring terminals or, after being released from the neuronal endings into the network of fenestrated capillaries and transported to the hypophysis, they may be involved in the regulation of secretion of adenohypophyseal hormones. Recent demonstrations of extensive colocalizations of these biologically active substances in individual axonal endings in the ME with wide spectrum of biological actions further emphasizes the ME as an important place involved in the neuroendocrine regulatory processes.

Animals↗
PubMed2005

[Self-organizing neural networks for automatic detection and classification of contrast (media) enhancement of lesions in dynamic MR-mammography].

PURPOSE: Investigation and statistical evaluation of "Self-Organizing Maps," a special type of neural networks in the field of artificial intelligence, classifying contrast enhancing lesions in dynamic MR-mammography. MATERIAL AND METHODS: 176 investigations with proven histology after core biopsy or operation were randomly divided into two groups. Several Self-Organizing Maps were trained by investigations of the first group to detect and classify contrast enhancing lesions in dynamic MR-mammography. Each single pixel's signal/time curve of all patients within the second group was analyzed by the Self-Organizing Maps. The likelihood of malignancy was visualized by color overlays on the MR-images. At last assessment of contrast-enhancing lesions by each different network was rated visually and evaluated statistically. RESULTS: A well balanced neural network achieved a sensitivity of 90.5 % and a specificity of 72.2 % in predicting malignancy of 88 enhancing lesions. Detailed analysis of false-positive results revealed that every second fibroadenoma showed a "typical malignant" signal/time curve without any chance to differentiate between fibroadenomas and malignant tissue regarding contrast enhancement alone; but this special group of lesions was represented by a well-defined area of the Self-Organizing Map. DISCUSSION: Self-Organizing Maps are capable of classifying a dynamic signal/time curve as "typical benign" or "typical malignant." Therefore, they can be used as second opinion. In view of the now known localization of fibroadenomas enhancing like malignant tumors at the Self-Organizing Map, these lesions could be passed to further analysis by additional post-processing elements (e.g., based on T2-weighted series or morphology analysis) in the future.

Algorithms↗
PubMed2001

Cortical correlates of gesture processing: clues to the cerebral mechanisms underlying apraxia during the imitation of meaningless gestures.

The clinical test of imitation of meaningless gestures is highly sensitive in revealing limb apraxia after dominant left brain damage. To relate lesion locations in apraxic patients to functional brain activation and to reveal the neuronal network subserving gesture representation, repeated H2(15O)-PET measurements were made in seven healthy subjects during a gesture discrimination task. Observing paired images of either meaningless hand or meaningless finger gestures, subjects had to indicate whether they were identical or different. As a control condition subjects simply had to indicate whether two portrayed persons were identical or not. Brain activity during the discrimination of hand gestures was strongly lateralized to the left hemisphere, a prominent peak activation being localized within the inferior parietal cortex (BA40). The discrimination of finger gestures induced a more symmetrical activation and rCBF peaks in the right intraparietal sulcus and in medial visual association areas (BA18/19). Two additional foci of prominent rCBF increase were found. One focus was located at the left lateral occipitotemporal junction (BA 19/37) and was related to both tasks; the other in the pre-SMA was particularly related to hand gestures. The pattern of task-dependent activation corresponds closely to the predictions made from the clinical findings, and underlines the left brain dominance for meaningless hand gestures and the critical involvement of the parietal cortex. The lateral visual association areas appear to support first stages of gesture representation, and the parietal cortex is part of the dorsal action stream. Finger gestures may require in addition precise visual analysis and spatial attention enabled by occipital and right intraparietal activity. Pre-SMA activity during the perception of hand gestures may reflect engagement of a network that is intimately related to gesture execution.

Adult↗