Age and gender influence on maximal bite force and masticatory muscles thickness

The present study aimed investigate the age and gender influence on maximal molar bite force and at outlining the criteria for normal masticatory muscle development in a sample of 177 Brazilian Caucasian dentate individuals aged 7-80 years divided into five age groups: I(7-12 years), II (13-20 years), III (21-40 years), IV (41-60 years), and V (61-80 years). Except for Group V, which comprised nine women and eight men, all groups were equally divided in respect to gender (20 M/20 F). Bite force was recorded with a mouth-adapted 1000 N dynamometer and the highest out of three records was regarded as the maximal bite force. The data were submitted to multivariate statistical analysis (SPSS 17.0 p < 0.05). Effects of group and gender were found, but no interactions between them. The ANOVA showed significant differences between groups bilaterally. Bonferroni`s test showed that group I had significantly lower bite force means at both sides as compared to all groups, except group V. No differences were found between the left and right sides. In all the groups, gender was found to be a significant factor associated with maximal bite force. A global comparison including all the subjects and measures showed that the means of men were approximately 30% higher than those of women, within-group comparisons yielded similar results in all groups. Muscle thickness was measured with a SonoSite Titan ultrasound tool using a high-resolution real-time 56 mm/10 MHz linear-array transducer. Three ultrasound images were obtained from the bilateral masseter and temporal muscles at rest and at maximal voluntary contraction. The means of the three measures in each clinical condition were analyzed with multivariate statistical analysis (SPSS 17.0 p < 0.05). A gradual increase in thickness of the masseter and temporal muscles was found both at rest and maximal voluntary contraction for groups I to IV, whereas a decrease in muscle thickness was observed in group V. Multivariate analysis showed that in both conditions there was an effect of group and gender. The study of the development of the stomatognathic system in relation to age and gender can provide useful data for the identification of normal and impaired functioning patterns. The results of this study indicate that age and gender are associated with structural and functional alterations in the muscles of the stomatognathic system. (C) 2010 Elsevier Ltd. All rights reserved.

Neural Basis of Delta-9-Tetrahydrocannabinol and Cannabidiol: Effects During Response Inhibition

Background: This study examined the effect of Delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) on brain activation during a motor inhibition task. Methods: Functional magnetic resonance imaging and behavioural measures were recorded while 15 healthy volunteers performed a Go/No-Go task following administration of either THC or CBD or placebo in a double-blind, pseudo-randomized, placebo-controlled repeated measures within-subject design. Results: Relative to placebo, THC attenuated activation in the right inferior frontal and the anterior cingulate gyrus. In contrast, CBD deactivated the left temporal cortex and insula. These effects were not related to changes in anxiety, intoxication, sedation, and psychotic symptoms. Conclusions: These data suggest that THC attenuates the engagement of brain regions that mediate response inhibition. CBD modulated function in regions not usually implicated in response inhibition.

Modulation of Auditory and Visual Processing by Delta-9-Tetrahydrocannabinol and Cannabidiol: an fMRI Study

Although the effects of cannabis on perception are well documented, little is known about their neural basis or how these may contribute to the formation of psychotic symptoms. We used functional magnetic resonance imaging (fMRI) to assess the effects of Delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) during visual and auditory processing in healthy volunteers. In total, 14 healthy volunteers were scanned on three occasions. Identical 10mg THC, 600mg CBD, and placebo capsules were allocated in a balanced double-blinded pseudo-randomized crossover design. Plasma levels of each substance, physiological parameters, and measures of psychopathology were taken at baseline and at regular intervals following ingestion of substances. Volunteers listened passively to words read and viewed a radial visual checkerboard in alternating blocks during fMRI scanning. Administration of THC was associated with increases in anxiety, intoxication, and positive psychotic symptoms, whereas CBD had no significant symptomatic effects. THC decreased activation relative to placebo in bilateral temporal cortices during auditory processing, and increased and decreased activation in different visual areas during visual processing. CBD was associated with activation in right temporal cortex during auditory processing, and when contrasted, THC and CBD had opposite effects in the right posterior superior temporal gyrus, the right-sided homolog to Wernicke`s area. Moreover, the attenuation of activation in this area (maximum 61, -15, -2) by THC during auditory processing was correlated with its acute effect on psychotic symptoms. Single doses of THC and CBD differently modulate brain function in areas that process auditory and visual stimuli and relate to induced psychotic symptoms. Neuropsychopharmacology (2011) 36, 1340-1348; doi:10.1038/npp.2011.17; published online 16 March 2011

Mild cognitive deficits associated to neocortical microgyria in mice with genetic deletion of cellular prion protein

The cellular prion protein (PrP(c)) has been implicated with the modulation of neuronal apoptosis, adhesion, neurite outgrowth and maintenance which are processes involved in the neocortical development. Malformations of cortical development (MCD) are frequently associated with neurological conditions including mental retardation, autism, and epilepsy. Here we investigated the behavioral performance of female adult PrP(c)-null mice (Prnp(%)) and their wild-type controls (Prnp(+/+)) presenting unilateral polymicrogyria, a MCD experimentally induced by neonatal freeze-lesion in the right hemisphere. injured mice from both genotypes presented similar locomotor activity but Prnp(%) mice showed a tendency to increase anxiety-related responses when compared to Prnp(+/+) animals. Additionally, injured Prnp(%) mice have a poorer performance in the social recognition task than sham-operated and Prnp(%) injured ones. Moreover the step-down inhibitory avoidance task was not affected by the procedure or the genotype of the animals. These data suggest that the genetic deletion of PrP(c) confers increased susceptibility to short-term social memory deficits induced by neonatal freezing model of polymicrogyria in mice. (C) 2008 Published by Elsevier B.V.

STATIC IMAGES WITH DIFFERENT INDUCED INTENSITIES OF HUMAN BODY MOVEMENTS AFFECT SUBJECTIVE TIME

Modulation of subjective time was examined using static images eliciting perceptions of different intensities of body movement. Undergraduate students were exposed to photographs of dancer sculptures in different dance positions for 36 sec. and asked to estimate the exposure duration. Lower movement intensities were related to shorter estimated durations. Mean durations for images of unmoving dancers were underestimated and for dancers taking a ballet step were overestimated. Temporal estimations were also related to the order of presentation of the stimuli, which suggested that subjective time estimations were influenced by the experimental context. Subjective time is related not only to the visual perception of moving images, but also of elicited perceptions of movement in static images, suggesting an embodiment effect on subjective time estimation.

Equal Numbers of Neuronal and Nonneuronal Cells Make the Human Brain an Isometrically Scaled-Up Primate Brain

The human brain is often considered to be the most cognitively capable among mammalian brains and to be much larger than expected for a mammal of our body size. Although the number of neurons is generally assumed to be a determinant of computational power, and despite the widespread quotes that the human brain contains 100 billion neurons and ten times more glial cells, the absolute number of neurons and glial cells in the human brain remains unknown. Here we determine these numbers by using the isotropic fractionator and compare them with the expected values for a human-sized primate. We find that the adult male human brain contains on average 86.1 +/- 8.1 billion NeuN-positive cells (""neurons"") and 84.6 +/- 9.8 billion NeuN-negative (""nonneuronal"") cells. With only 19% of all neurons located in the cerebral cortex, greater cortical size (representing 82% of total brain mass) in humans compared with other primates does not reflect an increased relative number of cortical neurons. The ratios between glial cells and neurons in the human brain structures are similar to those found in other primates, and their numbers of cells match those expected for a primate of human proportions. These findings challenge the common view that humans stand out from other primates in their brain composition and indicate that, with regard to numbers of neuronal and nonneuronal cells, the human brain is an isometrically scaled-up primate brain. J. Comp. Neurol. 513:532-541, 2009. (c) 2009 Wiley-Liss, Inc.

The renin-angiotensin system is upregulated in the cortex and hippocampus of patients with temporal lobe epilepsy related to mesial temporal sclerosis

Purpose: As reported by several authors, angiotensin II (AngII) is a proinflammatory molecule that stimulates the release of inflammatory cytokines and activates nuclear factor kappa B (NF kappa B), being also associated with the increase of cellular oxidative stress. Its production depends on the activity of the angiotensin converting enzyme (ACE) that hydrolyzes the inactive precursor angiotensin I (AngI) into AngII. It has been suggested that AngII underlies the physiopathological mechanisms of several brain disorders such as stroke, bipolar disorder, schizophrenia, and disease. The aim of the present work was to localize and quantify AngII AT1 and AT2 receptors in the cortex and hippocampus of patients with temporal lobe epilepsy related to mesial temporal sclerosis (MTS) submitted to corticoamygdalohippocampectomy for seizure control. Method: Immunohistochemistry, Western blot, and real-time PCR techniques were employed to analyze the expression of these receptors. Results: The results showed an upregulation of AngII AT1 receptor as well as its messenger ribonucleic acid (mRNA) expression in the cortex and hippocampus of patients with MTS. In addition, an increased immunoexpression of AngII AT2 receptors was found only in the hippocampus of these patients with no changes in its mRNA levels. Discussion: These data show, for the first time, changes in components of renin-angiotensin system (RAS) that could be implicated in the physiopathology of MTS.

Effect of image analysis software on neurofunctional activation during processing of emotional human faces

Functional brain imaging techniques such as functional MRI (fMRI) that allow the in vivo investigation of the human brain have been exponentially employed to address the neurophysiological substrates of emotional processing. Despite the growing number of fMRI studies in the field, when taken separately these individual imaging studies demonstrate contrasting findings and variable pictures, and are unable to definitively characterize the neural networks underlying each specific emotional condition. Different imaging packages, as well as the statistical approaches for image processing and analysis, probably have a detrimental role by increasing the heterogeneity of findings. In particular, it is unclear to what extent the observed neurofunctional response of the brain cortex during emotional processing depends on the fMRI package used in the analysis. In this pilot study, we performed a double analysis of an fMRI dataset using emotional faces. The Statistical Parametric Mapping (SPM) version 2.6 (Wellcome Department of Cognitive Neurology, London, UK) and the XBAM 3.4 (Brain Imaging Analysis Unit, Institute of Psychiatry, Kings College London, UK) programs, which use parametric and non-parametric analysis, respectively, were used to assess our results. Both packages revealed that processing of emotional faces was associated with an increased activation in the brain`s visual areas (occipital, fusiform and lingual gyri), in the cerebellum, in the parietal cortex, in the cingulate cortex (anterior and posterior cingulate), and in the dorsolateral and ventrolateral prefrontal cortex. However, blood oxygenation level-dependent (BOLD) response in the temporal regions, insula and putamen was evident in the XBAM analysis but not in the SPM analysis. Overall, SPM and XBAM analyses revealed comparable whole-group brain responses. Further Studies are needed to explore the between-group compatibility of the different imaging packages in other cognitive and emotional processing domains. (C) 2009 Elsevier Ltd. All rights reserved.

Proteome analysis of human dorsolateral prefrontal cortex using shotgun mass spectrometry

The prefrontal cortex executes important functions such as differentiation of conflicting thoughts, correct social behavior and personality expression, and is directly implicated in different neurodegenerative diseases. We performed a shotgun proteome analysis that included IEF fractionation, RP-LC, and MALDI-TOF/TOF mass spectrometric analysis of tryptic digests from a pool of seven human dorsolateral prefrontal cortex protein extracts. In this report, we present a catalog of 387 proteins expressed in these samples, identified by two or more peptides and high confidence search scores. These proteins are involved in different biological processes such as cell growth and/or maintenance, metabolism/energy pathways, cell communication/signal trarisduction, protein metabolism, transport, regulation of nucleobase, nucleoside, nucleotide and nucleic acid metabolism, and immune response. This analysis contributes to the knowledge of the human brain proteome by adding sample diversity and protein expression data from an alternative technical approach. It will also aid comparative studies of different brain areas and medical conditions, with future applications in basic and clinical research.

Effects of flooding of the River Paraná on the temporal activity of Anopheles (Nyssorhynchus) darlingi Root (Diptera: Culicidae), at the border state of Mato Grosso do Sul and São Paulo, Brazil

INTRODUCTION: Study of the temporal activity of malaria vectors during the implantation of a hydroelectric power station on the River Paraná, intended to generate electrical energy. The river separates the States of São Paulo and Mato Grosso do Sul, in Brazil. The objective was to verify whether alterations occurred in the wealth and diversity indices of Anopheles, following two successive floods, extended to the temporal activity and nycthemeral rhythm followed over a five year period. METHODS: Mosquito capture was performed monthly using the Human Attraction Technique and Shannon Traps. The first, executed for 24h, provided the nycthemeral rhythm and the second, lasting 15h, permitted the tracking of Anopheles during the two floods. RESULTS: The bimodal pattern of Anopheles darlingi defined before these floods was modified throughout the environment interventions. The same effect had repercussions on the populations of An albitarsis s.l., An triannulatus and An galvaoi. Activity prior to twilight was less affected by the environment alterations. CONCLUSIONS: The dam construction provoked changes in Anopheles temporal activity patterns, permitting classification of the area as an ecologically steady and unstable situation. Differences observed in Anopheles behavior due to the capture methods revealed the influence of solo and multiple attractiveness inside the populations studied.

Positive Selection Results in Frequent Reversible Amino Acid Replacements in the G Protein Gene of Human Respiratory Syncytial Virus

Human respiratory syncytial virus (HRSV) is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly temporal pattern of genetic variation, with a replacement of dominant genotypes occurring during consecutive years. In the present study we utilized phylogenetic methods to detect and map sites subject to adaptive evolution in the G protein of HRSVA and HRSVB. A total of 29 and 23 amino acid sites were found to be putatively positively selected in HRSVA and HRSVB, respectively. Several of these sites defined genotypes and lineages within genotypes in both groups, and correlated well with epitopes previously described in group A. Remarkably, 18 of these positively selected tended to revert in time to a previous codon state, producing a ""flipflop'' phylogenetic pattern. Such frequent evolutionary reversals in HRSV are indicative of a combination of frequent positive selection, reflecting the changing immune status of the human population, and a limited repertoire of functionally viable amino acids at specific amino acid sites.

Breastfeeding, sleep and wake circadian rhythms show distinct temporal emerging patterns

The emerging patterns of breastfeeding, sleep and wake circadian rhythms in an infant and the breastfeeding emergence pattern of his elder sister are presented. Both children were raised under regular contact with photic and non-photic Zeitgebers. Data are related to the first four months of life of the infants, which correspond to the exclusive and ad libitum breastfeeding stage of their lives. Discrimination is made of fasting-associated-wakefulness (FAW) which is a wake state without feeding. Our data show that while FAW episodes are concentrated in the diurnal phase of the day since the first week of life, breastfeeding rhythm takes longer to show statistically significant circadian periodicity (four weeks) and to become monophasic, concentrated in the diurnal phase of the day (three/four months). This precedence of the consolidation of FAW rhythm indicates tight association between nocturnal sleep fragmentation and the drive to feed, in the first months of life of infants.

Antinociceptive effect of stimulating the occipital or retrosplenial cortex in rats

A role for the occipital or retrosplenial cortex in nociceptive processing has not been demonstrated yet, but connections from these cortices to brain structures involved in descending pain-inhibitory mechanisms were already demonstrated. This study demonstrated that the electrical stimulation of the occipital or retrosplenial cortex produces antinociception in the rat tail-flick and formalin tests. Bilateral lesions of the dorsolateral funiculus abolished the effect of cortical stimulation in the tail-flick test. Injection of glutamate into the same targets was also antinociceptive in the tail-flick test. No rats stimulated in the occipital or retrosplenial cortex showed any change in motor performance on the Rota-rod test, or had epileptiform changes in the EEG recording during or up to 3 hours after stimulation. The antinociception induced by occipital cortex stimulation persisted after neural block of the retrosplenial cortex. The effect of retrosplenial cortex stimulation also persisted after neural block of the occipital cortex. We conclude that stimulation of the occipital or retrosplenial cortex in rats leads to antinociception activating distinct descending pain-inhibitory mechanisms, and this is unlikely to result from a reduced motor performance or a postictal phenomenon. Perspective: This study presents evidence that stimulation of the retrosplenial or occipital cortex produces antinociception in rat models of acute pain. These findings enhance our understanding of the role of the cerebral cortex in control of pain. (C) 2010 by the American Pain Society

Prospective ultramorphological characterization of human hair by optical coherence tomography

Background/purpose The continuous advancement in cosmetic science has led to an increasing demand for the development of non-invasive, reliable scientific techniques directed toward claim substantiation, which is of utmost relevance, to obtain data regarding the efficacy and safety of cosmetic products. Methods In this work, we used the optical coherence tomography (OCT) technique to produce in vitro transversal section-images of human hair. We also compared the OCT signal before and after chemical treatment with an 18% w/w ammonium thioglycolate solution. Results The mean diameter of the medulla was 29 +/- 7 mu m and the hair diameter was 122 +/- 16 mu m in our samples of standard Afro-ethnic hair. A three-dimensional (3D) image was constructed starting from 601 cross-sectional images (slices). Each slice was taken in steps of 6.0 mu m at eight frames per second, and the entire 3D image was constructed in 60 s. Conclusion It was possible to identify, using the A-scan protocol, the principal structures: the cuticle, cortex and medulla. After chemical treatment, it was not possible to identify the main structures of hair fiber due to index matching promoted by deleterious action of the chemical agent.

Midazolam reduces the selective activation of the rhinal cortex by contextual fear stimuli

Independent brain circuits appear to underlie different forms of conditioned fear, depending on the type of conditioning used, such as a context or explicit cue paired with footshocks. Several clinical reports have associated damage to the medial temporal lobe (MTL) with retrograde amnesia. Although a number of studies have elucidated the neural circuits underlying conditioned fear, the involvement of MTL components in the aversive conditioning paradigm is still unclear. To address this issue, we assessed freezing responses and Fos protein expression in subregions of the rhinal cortex and ventral hippocampus of rats following exposure to a context, light or tone previously paired with footshock (Experiment 1). A comparable degree of freezing was observed in the three types of conditioned fear, but with distinct patterns of Fos distribution. The groups exposed to cued fear conditioning did not show changes in Fos expression, whereas the group subjected to contextual fear conditioning showed selective activation of the ectorhinal (Ect), perirhinal (Per), and entorhinal (Ent) cortices, with no changes in the ventral hippocampus. We then examined the effects of the benzodiazepine midazolam injected bilaterally into these three rhinal subregions in the expression of contextual fear conditioning (Experiment 2). Midazolam administration into the Ect, Per, and Ent reduced freezing responses. These findings suggest that contextual and explicit stimuli endowed with aversive properties through conditioning recruit distinct brain areas, and the rhinal cortex appears to be critical for storing context-, but not explicit cue-footshock, associations. (C) 2010 Elsevier B.V. All rights reserved.