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Cortical Areas (cortical + area)
Selected AbstractsEpileptiform synchronization in the cingulate cortexEPILEPSIA, Issue 3 2009Gabriella Panuccio Summary Purpose:, The anterior cingulate cortex (ACC),which plays a role in pain, emotions and behavior,can generate epileptic seizures. To date, little is known on the neuronal mechanisms leading to epileptiform synchronization in this structure. Therefore, we investigated the role of excitatory and inhibitory synaptic transmission in epileptiform activity in this cortical area. In addition, since the ACC presents with a high density of opioid receptors, we studied the effect of opioid agonism on epileptiform synchronization in this brain region. Methods:, We used field and intracellular recordings in conjunction with pharmacological manipulations to characterize the epileptiform activity generated by the rat ACC in a brain slice preparation. Results:, Bath-application of the convulsant 4-aminopyridine (4AP, 50 ,M) induced both brief and prolonged periods of epileptiform synchronization resembling interictal- and ictal-like discharges, respectively. Interictal events could occur more frequently before the onset of ictal activity that was contributed by N -methyl- d -aspartate (NMDA) receptors. Mu-opioid receptor activation abolished 4AP-induced ictal events and markedly reduced the occurrence of the pharmacologically isolated GABAergic synchronous potentials. Ictal discharges were replaced by interictal events during GABAergic antagonism; this GABA-independent activity was influenced by subsequent mu-opioid agonist application. Conclusions:, Our results indicate that both glutamatergic and GABAergic signaling contribute to epileptiform synchronization leading to the generation of electrographic ictal events in the ACC. In addition, mu-opioid receptors appear to modulate both excitatory and inhibitory mechanisms, thus influencing epileptiform synchronization in the ACC. [source] Panayiotopoulos Syndrome: An Important Electroclinical Example of Benign Childhood System EpilepsyEPILEPSIA, Issue 6 2007Michael Koutroumanidis Summary:, As a result of the converging evidence from multiple large independent studies, Panayiotopoulos syndrome (PS) is now formally recognized as a distinct clinical entity within the spectrum of benign focal epilepsies of childhood. Clinically, PS is manifested by predominantly autonomic seizures and electrographically with multifocal interictal spikes, while the few published ictal recordings have documented onsets of variable lobar topography. These typical electroclinical features do not allow straightforward assignment to a distinctive cortical area, rendering the term "focal",as we currently understand it,problematic. This is a critical review of the clinical and EEG features of PS, focusing on those characteristics that may shed some light on its so far elusive pathophysiology. We also explore its electroclinical similarities to other idiopathic "focal" epilepsies and its differences to symptomatic focal epilepsies that may also manifest with autonomic ictal symptoms and signs. This methodology allows the formation of a rational hypothesis on the pathophysiology of PS that seems to be emerging as a good model for the so-called "system" (nonsymptomatic) epilepsies, with potentially important taxonomic implications. [source] Does the medial orbitofrontal cortex have a role in social valuation?EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2010M. P. Noonan Abstract It has been claimed that social behaviour changes after lesions of the ventromedial prefrontal cortex (vmPFC). However, lesions in humans are rarely restricted to a well defined cortical area. Although vmPFC lesions usually include medial orbitofrontal cortex (mOFC), they typically also affect subgenual and/or perigenual anterior cingulate cortex. The purpose of the current study is to investigate the role of mOFC in social valuation and decision-making. We tested four macaque monkeys prior to and after focal lesions of mOFC. Comparison of the animals' pre- and postoperative performance revealed that, unlike lesions of anterior cingulate gyrus (ACCg), lesions of mOFC did not induce alterations in social valuation. MOFC lesions did, however, induce mild impairments in a probabilistic two-choice decision task, which were not seen after ACCg lesions. In summary, the double dissociation between the patterns of impairment suggest that vmPFC involvement in both decision-making and social valuation may be mediated by distinct subregions centred on mOFC and ACCg respectively. [source] Neuronal substrates of gaze following in monkeysEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2009Simone Kamphuis Abstract Human and non-human primates follow the gaze of their respective conspecific to identify objects of common interest. Whereas humans rely on eye-gaze for such purposes, monkeys preferentially use head-gaze information. Functional magnetic resonance imaging (fMRI) studies have delineated an area in the human superior temporal sulcus (STS), which is specifically activated when subjects actively follow the eye-gaze of others. Similarly, using fMRI, we have identified an analogous region in the monkey's middle STS responding to gaze following. Hence, although humans and monkeys might rely on different directional cues guiding their attention, they seem to deploy a similar and possibly homologous cortical area to follow the gaze of a conspecific. Our results support the idea that the eyes developed a new social function in human evolution, most likely to support cooperative mutual social interactions building on a phylogenetically old STS module for the processing of head cues. [source] Premotor transcranial direct current stimulation (tDCS) affects primary motor excitability in humansEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2008Klára Boros Abstract Recent studies have shown that repetitive transcranial magnetic stimulation (rTMS) over the premotor cortex (PM) modifies the excitability of the ipsilateral primary motor cortex (M1). Transcranial direct current stimulation (tDCS) is a new method to induce neuroplasticity in humans non-invasively. tDCS generates neuroplasticity directly in the cortical area under the electrode, but might also induce effects in distant brain areas, caused by activity modulation of interconnected areas. However, this has not yet been tested electrophysiologically. We aimed to study whether premotor tDCS can modify the excitability of the ipsilateral M1 via cortico-cortical connectivity. Sixteen subjects received cathodal and anodal tDCS of the PM and eight subjects of the dorsolateral prefrontal cortex. Premotor anodal, but not premotor cathodal or prefrontal tDCS, modified selectively short intracortical inhibition/intracortical facilitation (SICI/ICF), while motor thresholds, single test-pulse motor-evoked potential and input,output curves were stable throughout the experiments. Specifically, anodal tDCS decreased intracortical inhibition and increased paired-pulse excitability. The selective influence of premotor tDCS on intracortical excitability of the ipsilateral M1 suggests a connectivity-driven effect of tDCS on remote cortical areas. Moreover, this finding indirectly substantiates the efficacy of tDCS to modulate premotor excitability, which might be of interest for applications in diseases accompanied by pathological premotor activity. [source] Variation in the development of postcranial robusticity: an example from Çatalhöyük, TurkeyINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 3 2007L. W. Cowgill Abstract While the study of variation in adult postcranial robusticity has a long history, few analyses have examined the acquisition of postcranial robusticity within an ontogenetic context. This research evaluates differences in the ontogenetic trajectories of immature femora from three samples, in order to assess the point at which differences in levels of adult postcranial robusticity arise during development. Femoral midshaft cross-sectional properties were compared between three diverse samples: Neolithic agriculturalists from Çatalhöyük, Turkey (n,=,42); Byzantine agriculturalists from Çatalhöyük, Turkey (n,=,24); and urban Americans from the Denver Growth Study (n,=,151). While the two adult samples from Çatalhöyük do not differ statistically, both Neolithic and Byzantine adults have relatively larger cortical and total areas than the American urban adults, and these differences are clearly established by the age of six. In addition, by the age of three, individuals from the Denver Growth Study have already attained a greater percentage of their adult length, total area, and cortical area relative to those in both the Neolithic and Byzantine samples. These results indicate that the differing levels of postcranial robusticity characterising adult populations appear relatively early during development, and that populations vary in the rate and pattern through which adult levels of postcranial robusticity are achieved. Copyright © 2007 John Wiley & Sons, Ltd. [source] A test of two methods of radiographically deriving long bone cross-sectional properties compared to direct sectioning of the diaphysisINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 5 2002Jay T. Stock Abstract Numerous studies have made use of cross-sectional geometry to describe the distribution of cortical bone in long bone diaphyses. Several methods can be used to measure or estimate cross-sectional contours. Direct sectioning (DSM) of the diaphysis is not appropriate in most curatorial contexts, and is commonly substituted with methods based upon bi-planar radiography: a latex cast method (LCM) or an eccentric elliptical method (EEM). Previous studies have demonstrated that the EEM provides accurate estimates of area measurements, while providing less accurate estimates of second moments of area (Biknevicius & Ruff, 1992; Runestad et al., 1993; Lazenby, 1997). The LCM has been commonly employed, as a way to estimate section contours more accurately, yet the validity of this method has not been adequately documented. This study measures the agreement of these methods against DSM of long bone diaphyses using 21 sections of canine tibiae derived from a study of total hip arthroplasty. The accuracy and agreement of these methods is evaluated using reduced major axis regression, paired sample t-tests and tests for agreement (Bland & Altman, 1986). The results illustrate that the LCM provides a reasonable estimate of cross-sectional dimensions, producing cross-sectional properties that are on average within 5% of properties derived from the DSM. The EEM is found to provide adequate estimates of true cross-sectional areas, but poor estimates of second moments of area. The use of the LCM is supported for all cross-sectional properties, but the EEM is only accurate in total area, cortical area and percent cortical area estimates. Copyright © 2002 John Wiley & Sons, Ltd. [source] Effects of an ethanol,gasoline mixture: results of a 4-week inhalation study in ratsJOURNAL OF APPLIED TOXICOLOGY, Issue 3 2005I. Chu Abstract The inhalation toxicity of an ethanol,gasoline mixture was investigated in rats. Groups of 15 male and 15 female rats were exposed by inhalation to 6130 ppm ethanol, 500 ppm gasoline or a mixture of 85% ethanol and 15% gasoline (by volume, 6130 ppm ethanol and 500 ppm gasoline), 6 h a day, 5 days per week for 4 weeks. Control rats of both genders received HEPA[sol ]charcoal-filtered room air. Ten males and ten females from each group were killed after 4 weeks of treatment and the remaining rats were exposed to filtered room air for an additional 4 weeks to determine the reversibility of toxic injuries. Female rats treated with the mixture showed growth suppression, which was reversed after 4 weeks of recovery. Increased kidney weight and elevated liver microsomal ethoxyresorufin- O -deethylase (EROD) activity, urinary ascorbic acid, hippuric acid and blood lymphocytes were observed and most of the effects were associated with gasoline exposure. Combined exposure to ethanol and gasoline appeared to exert an additive effect on growth suppression. Inflammation of the upper respiratory tract was observed only in the ethanol,gasoline mixture groups, and exposure to either ethanol and gasoline had no effect on the organ, suggesting that an irritating effect was produced when the two liquids were mixed. Morphology in the adrenal gland was characterized by vacuolation of the cortical area. Although histological changes were generally mild in male and female rats and were reversed after 4 weeks, the changes tended to be more severe in male rats. Brain biogenic amine levels were altered in ethanol- and gasoline-treated groups; their levels varied with respect to gender and brain region. Although no general interactions were observed in the brain neurotransmitters, gasoline appeared to suppress dopamine concentrations in the nucleus accumbens region co-exposed to ethanol. It was concluded that treatment with ethanol and gasoline, at the levels studied, produced mild, reversible biochemical hematological and histological effects, with some indications of interactions when they were co-administered. Copyright © 2005 John Wiley & Sons, Ltd. [source] Aged mice have enhanced endocortical response and normal periosteal response compared with young-adult mice following 1 week of axial tibial compressionJOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2010Michael D Brodt Abstract With aging, the skeleton may lose its ability to respond to positive mechanical stimuli. We hypothesized that aged mice are less responsive to loading than young-adult mice. We subjected aged (22 months) and young-adult (7 months) BALB/c male mice to daily bouts of axial tibial compression for 1 week and evaluated cortical and trabecular responses using micro,computed tomography (µCT) and dynamic histomorphometry. The right legs of 95 mice were loaded for 60 rest-inserted cycles per day to 8, 10, or 12,N peak force (generating mid-diaphyseal strains of 900 to 1900 µ, endocortically and 1400 to 3100 µ, periosteally). At the mid-diaphysis, mice from both age groups showed a strong anabolic response on the endocortex (Ec) and periosteum (Ps) [Ec.MS/BS and Ps. MS/BS: loaded (right) versus control (left), p,<,.05]. Generally, bone formation increased with increasing peak force. At the endocortical surface, contrary to our hypothesis, aged mice had a significantly greater response to loading than young-adult mice (Ec.MS/BS and Ec.BFR/BS: 22 months versus 7 months, p,<,.001). Responses at the periosteal surface did not differ between age groups (p,>,.05). The loading-induced increase in bone formation resulted in increased cortical area in both age groups (loaded versus control, p,<,.05). In contrast to the strong cortical response, loading only weakly stimulated trabecular bone formation. Serial (in vivo) µCT examinations at the proximal metaphysis revealed that loading caused a loss of trabecular bone in 7-month-old mice, whereas it appeared to prevent bone loss in 22-month-old mice. In summary, 1 week of daily tibial compression stimulated a robust endocortical and periosteal bone-formation response at the mid-diaphysis in both young-adult and aged male BALB/c mice. We conclude that aging does not limit the short-term anabolic response of cortical bone to mechanical stimulation in our animal model. © 2010 American Society for Bone and Mineral Research [source] RANKL Inhibition with Osteoprotegerin Increases Bone Strength by Improving Cortical and Trabecular bone Architecture in Ovariectomized Rats,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2008Michael S Ominsky Abstract Introduction: Ovariectomy (OVX) results in bone loss caused by increased bone resorption. RANKL is an essential mediator of bone resorption. We examined whether the RANKL inhibitor osteoprotegerin (OPG) would preserve bone volume, density, and strength in OVX rats. Materials and Methods: Rats were OVX or sham-operated at 3 mo of age. Sham controls were treated for 6 wk with vehicle (Veh, PBS). OVX rats were treated with Veh or human OPG-Fc (10 mg/kg, 2/wk). Serum RANKL and TRACP5b was measured by ELISA. BMD of lumbar vertebrae (L1,L5) and distal femur was measured by DXA. Right distal femurs were processed for bone histomorphometry. Left femurs and the fifth lumbar vertebra (L5) were analyzed by ,CT and biomechanical testing, and L6 was analyzed for ash weight. Results: OVX was associated with significantly greater serum RANKL and osteoclast surface and with reduced areal and volumetric BMD. OPG markedly reduced osteoclast surface and serum TRACP5b while completely preventing OVX-associated bone loss in the lumbar vertebrae, distal femur, and femur neck. Vertebrae from OPG-treated rats had increased dry and ash weight, with no significant differences in tissue mineralization versus OVX controls. ,CT showed that trabecular compartments in OVX-OPG rats had significantly greater bone volume fraction, vBMD, bone area, trabecular thickness, and number, whereas their cortical compartments had significantly greater bone area (p < 0.05 versus OVX-Veh). OPG improved cortical area in L5 and the femur neck to levels that were significantly greater than OVX or sham controls (p < 0.05). Biomechanical testing of L5 and femur necks showed significantly greater maximum load values in the OVX-OPG group (p < 0.05 versus OVX-Veh). Bone strength at both sites was linearly correlated with total bone area (r2 = 0.54,0.74, p < 0.0001), which was also significantly increased by OPG (p < 0.05 versus OVX). Conclusions: OPG treatment prevented bone loss, preserved trabecular architecture, and increased cortical area and bone strength in OVX rats. [source] Exercise When Young Provides Lifelong Benefits to Bone Structure and Strength,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2007Stuart J Warden PT Abstract Short-term exercise in growing rodents provided lifelong benefits to bone structure, strength, and fatigue resistance. Consequently, exercise when young may reduce the risk for fractures later in life, and the old exercise adage of "use it or lose it" may not be entirely applicable to the skeleton. Introduction: The growing skeleton is most responsive to exercise, but low-trauma fractures predominantly occur in adults. This disparity has raised the question of whether exercised-induced skeletal changes during growth persist into adulthood where they may have antifracture benefits. This study investigated whether brief exercise during growth results in lifelong changes in bone quantity, structure, quality, and mechanical properties. Materials and Methods: Right forearms of 5-week-old Sprague-Dawley rats were exercised 3 days/week for 7 weeks using the forearm axial compression loading model. Left forearms were internal controls and not exercised. Bone quantity (mineral content and areal density) and structure (cortical area and minimum second moment of area [IMIN]) were assessed before and after exercise and during detraining (restriction to home cage activity). Ulnas were removed after 92 weeks of detraining (at 2 years of age) and assessed for bone quality (mineralization) and mechanical properties (ultimate force and fatigue life). Results: Exercise induced consistent bone quantity and structural adaptation. The largest effect was on IMIN, which was 25.4% (95% CI, 15.6,35.3%) greater in exercised ulnas compared with nonexercised ulnas. Bone quantity differences did not persist with detraining, whereas all of the absolute difference in bone structure between exercised and nonexercised ulnas was maintained. After detraining, exercised ulnas had 23.7% (95% CI, 13.0,34.3%) greater ultimate force, indicating enhanced bone strength. However, exercised ulnas also had lower postyield displacement (,26.4%; 95% CI, ,43.6% to ,9.1%), indicating increased brittleness. This resulted from greater mineralization (0.56%; 95% CI, 0.12,1.00%), but did not influence fatigue life, which was 10-fold greater in exercised ulnas. Conclusions: These data indicate that exercise when young can have lifelong benefits on bone structure and strength, and potentially, fracture risk. They suggest that the old exercise adage of "use it or lose it" may not be entirely applicable to the skeleton and that individuals undergoing skeletal growth should be encouraged to perform impact exercise. [source] Whole-Genome Scan for Linkage to Bone Strength and Structure in Inbred Fischer 344 and Lewis Rats,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2005Imranul Alam Abstract A genome-wide genetic linkage analysis identified several chromosomal regions influencing bone strength and structure in F2 progeny of Fischer 344 x Lewis inbred rats. Introduction: Inbred Fischer 344 (F344) and Lewis (LEW) rats are similar in body size, but the F344 rats have significantly lower BMD and biomechanical strength of the femur and spine compared with LEW rats. The goal of this study was to identify quantitative trait loci (QTL) linked to bone strength and structure in adult female F2 rats from F344 and LEW progenitors. Materials and Methods: The 595 F2 progeny from F344 x LEW rats were phenotyped for measures of bone strength (ultimate force {Fu}; energy to break {U}; stiffness {S}) of the femur and lumbar vertebra and structure (femur midshaft polar moment of inertia {Ip}; femur midshaft cortical area; vertebral area). A genome-wide scan was completed in the F2 rats using 118 microsatellite markers at an average interval of 20 cM. Multipoint quantitative linkage analysis was performed to identify chromosomal regions that harbor QTL for bone strength and structure phenotypes. Results: Evidence of linkage for femur and lumbar strength was observed on chromosomes (Chrs) 1, 2, 5, 10, and 19. Significant linkage for femoral structure was detected on Chrs 2, 4, 5, 7, and 15. QTLs affecting femoral strength on Chrs 2 and 5 were also found to influence femur structure. Unique QTLs on Chrs 1, 10, and 19 were found that contributed to variability in bone strength but had no significant effect on structure. Also, unique QTLs were observed on Chrs 4, 7, and 15 that affected only bone structure without any effect on biomechanics. Conclusion: We showed multiple genetic loci influencing bone strength and structure in F344 x LEW F2 rats. Some of these loci are homologous to mouse and human chromosomes previously linked to related bone phenotypes. [source] Adrenarche and Bone Modeling and Remodeling at the Proximal Radius: Weak Androgens Make Stronger Cortical Bone in Healthy Children,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2003Thomas Remer Abstract Adrenarche, the physiological increase in adrenal androgen secretion, may contribute to better bone status. Proximal radial bone and 24-h urinary steroid hormones were analyzed cross-sectionally in 205 healthy children and adolescents. Positive adrenarchal effects on radial diaphyseal bone were observed. Obviously, adrenarche is one determinant of bone mineral status in children. Introduction: Increased bone mass has been reported in several conditions with supraphysiological adrenal androgen secretion during growth. However, no data are available for normal children. Therefore, our aim was to examine whether adrenal androgens within their physiological ranges may be involved in the strengthening of diaphyseal bone during growth. Methods: Periosteal circumference (PC), cortical density, cortical area, bone mineral content, bone strength strain index (SSI), and forearm cross-sectional muscle area were determined with peripheral quantitative computed tomography (pQCT) at the proximal radial diaphysis in healthy children and adolescents. All subjects, aged 6,18 years, who collected a 24-h urine sample around the time of their pQCT analysis (100 boys, 105 girls), were included in the present study, and major urinary glucocorticoid (C21) and androgen (C19) metabolites were quantified using gas chromatography-mass spectrometry. Results and Conclusions: We found a significant influence of muscularity, but not of hormones, on periosteal modeling (PC) before the appearance of pubic hair (prepubarche). Similarly, no influence of total cortisol secretion (C21) was seen on the other bone variables. However, positive effects of C19 on cortical density (p < 0.01), cortical area (p < 0.001), bone mineral content (p < 0.001), and SSI (p < 0.001),reflecting, at least in part, reduction in intracortical remodeling,were observed in prepubarchal children after muscularity or age had been adjusted for. This early adrenarchal contribution to proximal radial diaphyseal bone strength was further confirmed for all cortical variables (except PC) when, instead of C19 and C21, specific dehydroepiandrosterone metabolites were included as independent variables in the multiple regression model. During development of pubic hair (pubarche), muscularity and pubertal stage rather than adrenarchal hormones seemed to influence bone variables. Our study shows that especially the prepubarchal increase in adrenal androgen secretion plays an independent role in the accretion of proximal radial diaphyseal bone strength in healthy children. [source] Intermittently Administered Human Parathyroid Hormone(1,34) Treatment Increases Intracortical Bone Turnover and Porosity Without Reducing Bone Strength in the Humerus of Ovariectomized Cynomolgus MonkeysJOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2001David B. Burr Abstract Cortical porosity in patients with hyperparathyroidism has raised the concern that intermittent parathyroid hormone (PTH) given to treat osteoporotic patients may weaken cortical bone by increasing its porosity. We hypothesized that treatment of ovariectomized (OVX) cynomolgus monkeys for up to 18 months with recombinant human PTH(1,34) [hPTH(1,34)] LY333334 would significantly increase porosity in the midshaft of the humerus but would not have a significant effect on the strength or stiffness of the humerus. We also hypothesized that withdrawal of PTH for 6 months after a 12-month treatment period would return porosity to control OVX values. OVX female cynomolgus monkeys were given once daily subcutaneous (sc) injections of recombinant hPTH(1,34) LY333334 at 1.0 ,g/kg (PTH1), 5.0 ,g/kg (PTH5), or 0.1 ml/kg per day of phosphate-buffered saline (OVX). Sham OVX animals (sham) were also given vehicle. After 12 months, PTH treatment was withdrawn from half of the monkeys in each treatment group (PTH1-W and PTH5-W), and they were treated for the remaining 6 months with vehicle. Double calcein labels were given before death at 18 months. After death, static and dynamic histomorphometric measurements were made intracortically and on periosteal and endocortical surfaces of sections from the middiaphysis of the left humerus. Bone mechanical properties were measured in the right humeral middiaphysis. PTH dose dependently increased intracortical porosity. However, the increased porosity did not have a significant detrimental effect on the mechanical properties of the bone. Most porosity was concentrated near the endocortical surface where its mechanical effect is small. In PTH5 monkeys, cortical area (Ct.Ar) and cortical thickness (Ct.Th) increased because of a significantly increased endocortical mineralizing surface. After withdrawal of treatment, porosity in PTH1-W animals declined to sham values, but porosity in PTH5-W animals remained significantly elevated compared with OVX and sham. We conclude that intermittently administered PTH(1,34) increases intracortical porosity in a dose-dependent manner but does not reduce the strength or stiffness of cortical bone. [source] Suppressed Bone Turnover by Bisphosphonates Increases Microdamage Accumulation and Reduces Some Biomechanical Properties in Dog RibJOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2000Tasuku Mashiba Abstract It has been hypothesized that suppression of bone remodeling allows microdamage to accumulate, leading to increased bone fragility. This study evaluated the effects of reduced bone turnover produced by bisphosphonates on microdamage accumulation and biomechanical properties of cortical bone in the dog rib. Thirty-six female beagles, 1,2 years old, were divided into three groups. The control group (CNT) was treated daily for 12 months with saline vehicle. The remaining two groups were treated daily with risedronate (RIS) at a dose of 0.5 mg/kg per day or alendronate (ALN) at 1.0 mg/kg per day orally. After sacrifice, the right ninth rib was assigned to cortical histomorphometry or microdamage analysis. The left ninth rib was tested to failure in three-point bending. Total cross-sectional bone area was significantly increased in both RIS and ALN compared with CNT, whereas cortical area did not differ significantly among groups. One-year treatment with RIS or ALN significantly suppressed intracortical remodeling (RIS, 53%; ALN, 68%) without impairment of mineralization and significantly increased microdamage accumulation in both RIS (155%) and ALN (322%) compared with CNT. Although bone strength and stiffness were not significantly affected by the treatments, bone toughness declined significantly in ALN (20%). Regression analysis showed a significant nonlinear relationship between suppressed intracortical bone remodeling and microdamage accumulation as well as a significant linear relationship between microdamage accumulation and reduced toughness. This study showed that suppression of bone turnover by high doses of bisphosphonates is associated with microdamage accumulation and reduced some mechanical properties of bone. [source] Assessment of Histomorphological Features of the Sternal End of the Fourth Rib for Age Estimation in Koreans,JOURNAL OF FORENSIC SCIENCES, Issue 6 2007M.S., Yi-Suk Kim M.D. Abstract:, The aim of this study was to assess the histomorphological features of the fourth rib and to develop age-predicting equations for Koreans. Sixty-four rib samples (36 males and 28 females) obtained from forensic cases were used for developing equations. Two thin sections (<100-,m thick) per sample were prepared by manual grinding. Multivariate analysis of covariance revealed statistically significant differences in age-adjusted histomorphological variables between sexes. Using stepwise regression analysis, osteon population density and average osteon area were correlated with unknown sex (r2 = 0.826), and sex plus two histomorphological variables provided the best results for an age-predicting equation given the assumption of knowing the sex of a specimen (r2 = 0.839). Average Haversian canal area had little influence on age estimation for male or female samples, and relative cortical area was not significantly related to age for any specimen. [source] Technical note: The effect of midshaft location on the error ranges of femoral and tibial cross-sectional parametersAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010Vladimír Sládek Abstract In comparing long-bone cross-sectional geometric properties between individuals, percentages of bone length are often used to identify equivalent locations along the diaphysis. In fragmentary specimens where bone lengths cannot be measured, however, these locations must be estimated more indirectly. In this study, we examine the effect of inaccurately located femoral and tibial midshafts on estimation of geometric properties. The error ranges were compared on 30 femora and tibiae from the Eneolithic and Bronze Age. Cross-sections were obtained at each 1% interval from 60 to 40% of length using CT scans. Five percent of deviation from midshaft properties was used as the maximum acceptable error. Reliability was expressed by mean percentage differences, standard deviation of percentage differences, mean percentage absolute differences, limits of agreement, and mean accuracy range (MAR) (range within which mean deviation from true midshaft values was less than 5%). On average, tibial cortical area and femoral second moments of area are the least sensitive to positioning error, with mean accuracy ranges wide enough for practical application in fragmentary specimens (MAR = 40,130 mm). In contrast, tibial second moments of area are the most sensitive to error in midshaft location (MAR = 14,20 mm). Individuals present significant variation in morphology and thus in error ranges for different properties. For highly damaged fossil femora and tibiae we recommend carrying out additional tests to better establish specific errors associated with uncertain length estimates. Am J Phys Anthropol 2010. © 2009 Wiley-Liss, Inc. [source] The effects of total hip arthroplasty on the structural and biomechanical properties of adult boneAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Joshua J. Peck Abstract The responsiveness of bone to mechanical stimuli changes throughout life, with adaptive potential generally declining after skeletal maturity is reached. This has led some to question the importance of bone functional adaptation in the determination of the structural and material properties of the adult skeleton. A better understanding of age-specific differences in bone response to mechanical loads is essential to interpretations of long bone adaptation. The purpose of this study is to examine how the altered mechanical loading environment and cortical bone loss associated with total hip arthroplasty affects the structural and biomechanical properties of adult bone at the mid-shaft femur. Femoral cross sections from seven individuals who had undergone unilateral total hip arthroplasty were analyzed, with intact, contralateral femora serving as an approximate internal control. A comparative sample of individuals without hip prostheses was also included in the analysis. Results showed a decrease in cortical area in femora with prostheses, primarily through bone loss at the endosteal envelope; however, an increase in total cross-sectional area and maintenance of the parameters of bone strength, Ix, Iy, and J, were observed. No detectable differences were found between femora of individuals without prostheses. We interpret these findings as an adaptive response to increased strains caused by loading a bone previously diminished in mass due to insertion of femoral prosthesis. These results suggest that bone accrued through periosteal apposition may serve as an important means by which adult bone can functional adapt to changes in mechanical loading despite limitations associated with senescence. Am J Phys Anthropol 2009. © 2008 Wiley-Liss, Inc. [source] Comparison of the ultrastructure of cortical and retinal terminals in the rat superior colliculusTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 8 2006Kamran Boka Abstract We compared the ultrastructure and synaptic targets of terminals of cortical or retinal origin in the stratum griseum superficiale and stratum opticum of the rat superior colliculus. Following injections of biotinylated dextran amine into cortical area 17, corticotectal axons were labeled by anterograde transport. Corticotectal axons were of relatively small caliber with infrequent small varicosities. At the ultrastructural level, corticotectal terminals were observed to be small profiles (0.44 ± 0.27 ,m2) that contained densely packed round vesicles. In tissue stained for gamma amino butyric acid (GABA) using postembedding immunocytochemical techniques, corticotectal terminals were found to contact small (0.51 ± 0.69 ,m2) non-GABAergic dendrites and spines (93%) and a few small GABAergic dendrites (7%). In the same tissue, retinotectal terminals, identified by their distinctive pale mitochondria, were observed to be larger than corticotectal terminals (3.34 ± 1.79 ,m2). In comparison to corticotectal terminals, retinotectal terminals contacted larger (1.59 ± 1.70 ,m2) non-GABAergic dendrites and spines (73%) and a larger proportion of GABAergic profiles (27%) of relatively large size (2.17 ± 1.49 ,m2), most of which were vesicle-filled (71%). Our results suggest that cortical and retinal terminals target different dendritic compartments within the neuropil of the superficial layers of the superior colliculus. Anat Rec Part A, 288A:850,858, 2006. © 2006 Wiley-Liss, Inc. [source] Comparative study of brain morphology in Mecp2 mutant mouse models of Rett syndromeTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2008Nadia P. Belichenko Abstract Rett syndrome (RTT) is caused by mutations in the X-linked gene MECP2. While patients with RTT show widespread changes in brain function, relatively few studies document changes in brain structure and none examine in detail whether mutations causing more severe clinical phenotypes are linked to more marked changes in brain structure. To study the influence of MeCP2-deficiency on the morphology of brain areas and axonal bundles, we carried out an extensive morphometric study of two Mecp2-mutant mouse models (Mecp2B and Mecp2J) of RTT. Compared to wildtype littermates, striking changes included reduced brain weight (,13% and ,9%) and the volumes of cortex (,11% and ,7%), hippocampus (both by ,8%), and cerebellum (,12% and 8%) in both mutant mice. At 3 weeks of age, most (24 of 47) morphological parameters were significantly altered in Mecp2B mice; fewer (18) were abnormal in Mecp2J mice. In Mecp2B mice, significantly lower values for cortical area were distributed along the rostrocaudal axis, and there was a reduced length of the olfactory bulb (,10%) and periaqueductal gray matter (,16%). In Mecp2J mice, while there was significant reduction in rostrocaudal length of cortex, this parameter was also abnormal in hippocampus (,10%), periaqueductal gray matter (,13%), fimbria (,18%), and anterior commissure (,10%). Our findings define patterns of Mecp2 mutation-induced changes in brain structure that are widespread and show that while some changes are present in both mutants, others are not. These observations provide the underpinning for studies to further define microarchitectural and physiological consequences of MECP2 deficiency. J. Comp. Neurol. 508:184,195, 2008. © 2008 Wiley-Liss, Inc. [source] Neuromotor development in nocturnal enuresisDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 9 2006Alexander von Gontard MD PhD In children with nocturnal enuresis, a higher rate of minor neurological dysfunction has been found. The aim of this study was to assess timed performance (a measure of motor performance speed) and associated movements using a standardized and reliable instrument. The motor function of 37 children with nocturnal enuresis (27 males, 10 females; mean age 10y 7mo [SD 1y 10mo]; age range 8y-14y 8mo) and 40 comparison children without enuresis (17 males, 23 females; mean age 10y 7mo [SD 1y 6mo]; age range 8y-14y 8mo) was assessed using the Zurich Neuromotor Assessment. Children with nocturnal enuresis showed a slower motor performance than comparison children, particularly for repetitive hand and finger movements. This study provides evidence for a maturational deficit in motor performance in children with nocturnal enuresis. In addition to a maturational deficit of the brainstem, it is proposed that there is a possible maturational deficit of the motor cortex circuitry and related cortical areas in children with nocturnal enuresis. [source] Differential effects of stress and amphetamine administration on Fos-like protein expression in corticotropin releasing factor-neurons of the rat brainDEVELOPMENTAL NEUROBIOLOGY, Issue 6 2007David Rotllant Abstract Corticotropin releasing factor (CRF) appears to be critical for the control of important aspects of the behavioral and physiological response to stressors and drugs of abuse. However, the extent to which the different brain CRF neuronal populations are similarly activated after stress and drug administration is not known. We then studied, using double immunohistochemistry for CRF and Fos protein, stress and amphetamine-induced activation of CRF neurons in cortex, central amygdala (CeA), medial parvocellular dorsal, and submagnocellular parvocellular regions of the paraventricular nucleus of the hypothalamus (PVNmpd and PVNsm, respectively) and Barrington nucleus (Bar). Neither exposure to a novel environment (hole-board, HB) nor immobilization (IMO) increased Fos-like immunoreactivity (FLI) in the CeA, but they did to the same extent in cortical regions. In other regions only IMO increased FLI. HB and IMO both failed to activate CRF+ neurons in cortical areas, but after IMO, some neurons expressing FLI in the PVNsm and most of them in the PVNmpd and Bar were CRF+. Amphetamine administration increased FLI in cortical areas and CeA (with some CRF+ neurons expressing FLI), whereas the number of CRF+ neurons increased only in the PVNsm, in contrast to the effects of IMO. The present results indicate that stress and amphetamine elicited a distinct pattern of brain Fos-like protein expression and differentially activated some of the brain CRF neuronal populations, despite similar levels of overall FLI in the case of IMO and amphetamine. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007. [source] Influence of parental deprivation on the behavioral development in Octodon degus: Modulation by maternal vocalizationsDEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2003Katharina Braun Abstract Repeated separation from the family during very early stages of life is a stressful emotional experience which induces a variety of neuronal and synaptic changes in limbic cortical areas that may be related to behavioral alterations. First, we investigated whether repeated parental separation and handling, without separation from the family, leads to altered spontaneous exploratory behavior in a novel environment (open field test) in 8-day-old Octodon degus. Second, we tested whether the parentally deprived and handled animals display different stimulus-evoked exploratory behaviors in a modified open field version, in which a positive emotional stimulus, the maternal call, was presented. In the open field test a significant influence of previous emotional experience was found for the parameters of running, rearing, and vocalization. Parentally deprived degus displayed increased horizontal (running) and vertical (rearing) motoric activities, but decreased vocalization, compared to normal and handled controls. The presentation of maternal vocalizations significantly modified running, vocalization, and grooming activities, which in the case of running activity was dependent on previous emotional experience. Both deprivation-induced locomotor hyperactivity together with the reduced behavioral response towards a familiar acoustic emotional signal are similar to behavioral disturbances observed in human attachment disorders. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 42: 237,245, 2003. [source] A shift from diffuse to focal cortical activity with developmentDEVELOPMENTAL SCIENCE, Issue 1 2006Sarah Durston Recent imaging studies have suggested that developmental changes may parallel aspects of adult learning in cortical activation becoming less diffuse and more focal over time. However, while adult learning studies examine changes within subjects, developmental findings have been based on cross-sectional samples and even comparisons across studies. Here, we used functional MRI in children to test directly for shifts in cortical activity during performance of a cognitive control task, in a combined longitudinal and cross-sectional study. Our longitudinal findings, relative to our cross-sectional ones, show attenuated activation in dorsolateral prefrontal cortical areas, paralleled by increased focal activation in ventral prefrontal regions related to task performance. [source] The cortex in multidimensional space: where do cortical areas come from?DEVELOPMENTAL SCIENCE, Issue 2 2001Marcy A. Kingsbury The concept of a cortical ,area' as a discrete phylogenetic, developmental and computational unit is evaluated. Evidence including the comparative organization of the forebrain in vertebrates, the organization of cortex in different mammals, the scaling of the areas of the isocortex in mammals, and the early molecular differentiation of the cortex all suggest a special status for the primary sensory cortical areas, particularly the visual cortex. Furthermore, the overlapping gradients of early molecular expression and the patterning of cortical structure and connectivity by thalamic input suggest a new view of cortical organization that is different from the traditional view of a developmentally mosaic cortex; this view proposes that distinct cortical areas arise combinatorily from the multiple overlapping processes imposed upon the developing cortex. [source] Peer Commentaries on Marcy A. Kingsbury and Barbara L. Finlay's The cortex in multidimensional space: where do cortical areas come from?DEVELOPMENTAL SCIENCE, Issue 2 2001Article first published online: 28 JUN 200 Elizabeth Bates, Brain evolution and development: passing through the eye of the needle, p. 143 Serena M. Dudek, Multidimensional gene expression in cortical space, p. 145 Henry Kennedy and Colette Dehay, Gradients and boundaries: limits of modularity and its influence on the isocortex, p. 147 Sarah L. Pallas, Specification of mammalian neocortex: the power of the evo,devo approach in resolving the nature,nurture dichotomy, p. 148 Michel Roger, Embryonic stage of commitment of neocortical cells to develop area-specific connections, p. 151 M.W. Spratling and M.H. Johnson, Activity-dependent processes in regional cortical specialization, p. 153 [source] Coexistence of symptomatic focal and absence seizures: Video-EEG and EEG-fMRI evidence of overlapping but independent epileptogenic networksEPILEPSIA, Issue 7 2009Serge Chassagnon Summary The distinction between typical absences and hypomotor seizures in patients having frontal lesions is difficult. In focal epilepsy, generalized-like interictal discharges can reflect either a coexistent generalized epileptic trait or a secondary bilateral synchrony. Using combined measures of the EEG and blood oxygenation level dependent (BOLD) activity, we studied a 50-year-old patient with both absence-like and symptomatic focal motor seizures. Focal activity induced activation in the lesional area and deactivation in the contralateral central cortex. Generalized spike-and-wave discharges (GSWDs) resulted also in perilesional activation, and multifocal symmetrical cortical and thalamic activations, and deactivation in associative cortical areas. Although the central cortex was involved during both types of epileptic activity, electroencephalography (EEG),functional magnetic resonance imaging (fMRI) revealed distinct neuronal networks at the time of the focal or generalized discharges, allowing a clear-cut differentiation of the generators. Whether the patient had distinct epileptic syndromes or distinct electrographic patterns from the lesional trigger remains debatable. [source] Electroencephalographic Characterization of an Adult Rat Model of Radiation-Induced Cortical DysplasiaEPILEPSIA, Issue 10 2001Shinji Kondo Summary: ,Purpose: Cortical dysplasia (CD) is a frequent cause of medically intractable focal epilepsy. The mechanisms of CD-induced epileptogenicity remain unknown. The difficulty in obtaining and testing human tissue warrants the identification and characterization of animal model(s) of CD that share most of the clinical, electroencephalographic (EEG), and histopathologic characteristics of human CD. In this study, we report on the in vivo EEG characterization of the radiation-induced model of CD. Methods: Timed-pregnant Sprague,Dawley rats were irradiated on E17 using a single dose of 145 cGy or left untreated. Their litters were identified and implanted with bifrontal epidural and hippocampal depth electrodes for prolonged continuous EEG recordings. After prolonged EEG monitoring, animals were killed and their brains sectioned and stained for histologic studies. Results: In utero,irradiated rats showed frequent spontaneous interictal epileptiform spikes and spontaneous seizures arising independently from the hippocampal or the frontal neocortical structures. No epileptiform or seizure activities were recorded from age-matched control rats. Histologic studies showed the presence of multiple cortical areas of neuronal clustering and disorganization. Moreover, pyramidal cell dispersion was seen in the CA1>CA3 areas of the hippocampal formations. Conclusions: Our results further characterize the in vivo EEG characteristics of the in utero radiation model of CD using long-term EEG monitoring. This model may be used to study the molecular and cellular changes in epileptogenic CD and to test the efficacy of newer antiepileptic medications. [source] Major and minor depression in Parkinson's disease: a neuropsychological investigationEUROPEAN JOURNAL OF NEUROLOGY, Issue 9 2006A. Costa Previous studies have failed to distinguish the differential contribution of major and minor depression to cognitive impairment in patients with idiopathic Parkinson's disease (PD). This study was aimed at investigating the relationships among major depression (MD), minor depression (MiD) and neuropsychological deficits in PD. Eighty-three patients suffering from PD participated in the study. MD and MiD were diagnosed by means of a structured interview (SCID-I) based on the DSM-IV criteria, and severity of depression was evaluated by the Beck Depression Inventory. For the neuropsychological assessment, we used standardized scales that measure verbal and visual episodic memory, working memory, executive functions, abstract reasoning and visual-spatial and language abilities. MD patients performed worse than PD patients without depression on two long-term verbal episodic memory tasks, on an abstract reasoning task and on three measures of executive functioning. The MiD patients' performances on the same tests fell between those of the other two groups of PD patients but did not show significant differences. Our results indicate that MD in PD is associated with a qualitatively specific neuropsychological profile that may be related to an alteration of prefrontal and limbic cortical areas. Moreover, the same data suggest that in these patients MiD and MD may represent a gradual continuum associated with increasing cognitive deficits. [source] Cortical control of thermoregulatory sympathetic activationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2010M. Fechir Abstract Thermoregulation enables adaptation to different ambient temperatures. A complex network of central autonomic centres may be involved. In contrast to the brainstem, the role of the cortex has not been clearly evaluated. This study was therefore designed to address cerebral function during a whole thermoregulatory cycle (cold, neutral and warm stimulation) using 18-fluordeoxyglucose-PET (FDG-PET). Sympathetic activation parameters were co-registered. Ten healthy male volunteers were examined three times on three different days in a water-perfused whole-body suit. After a baseline period (32°C), temperature was either decreased to 7°C (cold), increased to 50°C (warm) or kept constant (32°C, neutral), thereafter the PET examination was performed. Cerebral glucose metabolism was increased in infrapontine brainstem and cerebellar hemispheres during cooling and warming, each compared with neutral temperature. Simultaneously, FDG uptake decreased in the bilateral anterior/mid-cingulate cortex during warming, and in the right insula during cooling and warming. Conjunction analyses revealed that right insular deactivation and brainstem activation appeared both during cold and warm stimulation. Metabolic connectivity analyses revealed positive correlations between the cortical activations, and negative correlations between these cortical areas and brainstem/cerebellar regions. Heart rate changes negatively correlated with glucose metabolism in the anterior cingulate cortex and in the middle frontal gyrus/dorsolateral prefrontal cortex, and changes of sweating with glucose metabolism in the posterior cingulate cortex. In summary, these results suggest that the cerebral cortex exerts an inhibitory control on autonomic centres located in the brainstem or cerebellum. These findings may represent reasonable explanations for sympathetic hyperactivity, which occurs, for example, after hemispheric stroke. [source] | ||||||||||||||||||||||||||||||||||