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.

Owing to methodological shortcomings and a certain conservatism that consolidates wrong assumptions in the literature, some dogmas have become established and reproduced in papers and textbooks, derived from quantitative features of the brain. The first dogma states that the cerebral cortex is the pinnacle of brain evolution - based on the observations that its volume is greater in more 'intelligent' species, and that cortical surface area grows more than any other brain region, to reach the largest proportion in higher primates and humans. The second dogma claims that the human brain contains 100 billion neurons, plus 10-fold more glial cells. These round numbers have become widely adopted, although data provided by different authors have led to a broad range of 75-125 billion neurons in the whole brain. The third dogma derives from the second, and states that our brain is structurally special, an outlier as compared with other primates. Being so large and convoluted, it is a special construct of nature, unrelated to evolutionary scaling. Finally, the fourth dogma appeared as a tentative explanation for the considerable growth of the brain throughout development and evolution - being modular in structure, the brain (and particularly the cerebral cortex) grows by tangential addition of modules that are uniform in neuronal composition. In this review, we sought to examine and challenge these four dogmas, and propose other interpretations or simply their replacement with alternative views.

SUMMARY In primates, posterior auditory cortical areas are thought to be part of a dorsal auditory pathway that processes spatial information. But how posterior (and other) auditory areas represent acoustic space remains a matter of debate. Here we provide new evidence based on functional magnetic resonance imaging (fMRI) of the macaque indicating that space is predominantly represented by a distributed hemi-field code rather than by a local spatial topography. Hemifield tuning in cortical and subcortical regions emerges from an opponent hemispheric pattern of activation and deactivation that depends on the availability of interaural delay cues. Importantly, these opponent signals allow responses in posterior regions to segregate space similarly to a hemifield code representation. Taken together, our results reconcile seemingly contradictory views by showing that the representation of space follows closely a hemifield code and suggest that enhanced posterior-dorsal spatial specificity in primates might emerge from this form of coding.

BMMCs infusion is feasible and practical in a clinical setting. In vivo tracking of labelled cells demonstrated that the hepatic artery route successfully delivered BMMCs to the liver. The early improvement of laboratory indices of liver function should be interpreted with caution, because this study was not designed to evaluate efficacy. The median Model for End-Stage Liver Disease score had not deteriorated 1 year later. The occurrence of a graft-versus-host disease-like phenomenon highlights the importance of sustained vigilance even when giving autologous cells. Controlled studies are needed to determine whether BMMCs infusion affects HCC development in cirrhosis.

Using functional magnetic resonance imaging in awake behaving monkeys we investigated how species-specific vocalizations are represented in auditory and auditory-related regions of the macaque brain. We found clusters of active voxels along the ascending auditory pathway that responded to various types of complex sounds: inferior colliculus (IC), medial geniculate nucleus (MGN), auditory core, belt, and parabelt cortex, and other parts of the superior temporal gyrus (STG) and sulcus (STS). Regions sensitive to monkey calls were most prevalent in the anterior STG, but some clusters were also found in frontal and parietal cortex on the basis of comparisons between responses to calls and environmental sounds. Surprisingly, we found that spectrotemporal control sounds derived from the monkey calls (“scrambled calls”) also activated the parietal and frontal regions. Taken together, our results demonstrate that species-specific vocalizations in rhesus monkeys activate preferentially the auditory ventral stream, and in particular areas of the antero-lateral belt and parabelt.

Paenibacillus polymyxa strain SCE2 was shown to inhibit the growth of different potential human pathogenic bacterial strains and fungi in vitro. To determine the genetic characterization of this antimicrobial substance, strain SCE2 was transformed with plasmid pTV32(Ts), a delivery vector for Tn917‐lac. After transposition, four mutants were shown to have lost their capability to inhibit Micrococcus sp. and Staphylococcus aureus RN450, but they continued to inhibit the growth of Corynebacterium fimi NCTC7547 and Escherichia coli HB101. Hybridization experiments using the DNA of the four mutants digested with different endonucleases and pTV32(Ts) as a probe showed that the place of insertion of Tn917‐lac in the chromosome was the same in mutants 4 and 36 and in mutants 31 and 59, but different between these pairs. It is thought possible that more than one antimicrobial substance is being produced by strain SCE2.

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-Objective: We compare duplex scan (DS) and magnetic resonance angiography (MRA) with digital angiography (DGA) in respect to accuracy in measuring internal carotid artery (IC) stenosis in symptomatic patients. Method: Ten symptomatic patients with IC stenosis greater than 70% previously diagnosed by DS were submitted to another DS and to both MRA and DGA. Both ICs from each patient (total 20 ICs) were evaluated by physicians blinded for the results of other tests. DS and MRA were compared with DGA, using the intraclass correlation coeficient (r) and its 95% confidence interval (95% ci). .or each diagnostic test, the study group (20 Ics) was also divided in surgical patients (IC stenosis between 70 and 99%) and non surgical patients, using kappa concordance coeficient (k) to compare the results. KEY WORDS: carotid stenosis, diagnosis, cerebrovascular disease, comparative study.Estenose da artéria carótida interna extracraniana: comparação de duplex-scan e angio-ressonância com angiografia digital RESUMO -Objetivo: .oram comparados duplex scan (DS) e angio-ressonância magnética (AGRM) com angiografia digital (AGD) na avaliação da estenose da artéria carótida interna (CI). Método: .oram estudados 10 pacientes sintomáticos com estenose da CI superior a 70% em estudos de triagem com DS. Os pacientes foram submetidos a novo DS, AGRM e AGD para estudo de ambas as CIs (total 20 CIs). O DS e a AGRM foram comparados com a AGD utilizando-se o coeficiente de correlação intra-classe (r) e o seu intervalo de confiança a 95% (ic 95%). Para cada método diagnóstico, o grupo de pacientes (considerando as 20 CIs) foi também dicotomizado em casos cirúrgicos (estenose entre 70% e 99%) e não cirúrgicos, utilizando-se o coeficiente kappa de concordância (k). Resultados: Na comparação entre DS e AGD, obteve-se r = 0,71 (0,4 -0,87). Entre AGRM e AGD, r = 0,61 (0,25 -0,82). Após a dicotomização da amostra, obteve-se, entre DS e AGD, k = 0,857, p < 0,0001; e entre AGRM e AGD, k = 0,545, p = 0,003. A maioria dos erros de DS e AGRM ocorreu nos casos de suboclusão arterial. Conclusão: Os resultados sugerem que o DS e a AGRM, usados em conjunto, podem substituir a AGD na indicação da endarterectomia carotídea, exceto quando há discordância entre os dois ou quando algum dos métodos detecta suboclusão arterial.