The planum temporale (PT) is a critical region of the language functional network in the human brain showing a striking size asymmetry toward the left hemisphere. Historically considered as a structural landmark of the left-brain specialization for language, a similar anatomical bias has been described in great apes but never in monkeys-indicating that this brain landmark might be unique to Hominidae evolution. In the present in vivo magnetic resonance imaging study, we show clearly for the first time in a nonhominid primate species, an Old World monkey, a left size predominance of the PT among 96 olive baboons (Papio anubis), using manual delineation of this region in each individual hemisphere. This asymmetric distribution was quasi-identical to that found originally in humans. Such a finding questions the relationship between PT asymmetry and the emergence of language, indicating that the origin of this cerebral specialization could be much older than previously thought, dating back, not to the Hominidae, but rather to the Catarrhini evolution at the common ancestor of humans, great apes and Old World monkeys, 30-40 million years ago.

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The baboon (Papio) brain is a remarkable model for investigating the brain. The current work aimed at creating a population-average baboon (Papio anubis) brain template and its left/right hemisphere symmetric version from a large sample of T1-weighted magnetic resonance images collected from 89 individuals. Averaging the prior probability maps output during the segmentation of each individual also produced the first baboon brain tissue probability maps for gray matter, white matter and cerebrospinal fluid. The templates and the tissue probability maps were created using state-of-the-art, freely available software tools and are being made freely and publicly available: http://www.nitrc.org/projects/haiko89/ or http://lpc.univ-amu.fr/spip.php?article589. It is hoped that these images will aid neuroimaging research of the baboon by, for example, providing a modern, high quality normalization target and accompanying standardized coordinate system as well as probabilistic priors that can be used during tissue segmentation.

Transabdominal ShearWave elastography of fetal lungs in pregnant baboons is feasible. However, intra- and inter-operator reproducibility is acceptable when the mean of three measurements is used. Further studies are thus needed before an objective study of lung maturity with ShearWave elastography can be carried out.

HTLV-1 causes Adult T cell Leukemia/Lymphoma (ATLL) in humans. We describe an ATL-like disease in a 9 year-old female baboon naturally infected with STLV-1 (the simian counterpart of HTLV-1), with a lymphocyte count over 1010/L, lymphocytes with abnormal nuclear morphology, and pulmonary and skin lesions. The animal was treated with a combination of AZT and alpha interferon. Proviral load (PVL) was measured every week. Because the disease continued to progress, the animal was euthanized. Abnormal infiltrates of CD3+CD25+ lymphocytes and Tax-positive cells were found by histological analyses in both lymphoid and non-lymphoid organs. PVL was measured and clonal diversity was assessed by LM-PCR (Ligation-Mediated Polymerase Chain Reaction) and high throughput sequencing, in blood during treatment and in 14 different organs. The highest PVL was found in lymph nodes, spleen and lungs. One major clone and a number of intermediate abundance clones were present in blood throughout the course of treatment, and in organs. These results represent the first multi-organ clonality study in ATLL. We demonstrate a previously undescribed clonal complexity in ATLL. Our data reinforce the usefulness of natural STLV-1 infection as a model of ATLL