Palaeoproteomics resolves sloth relationships

The living tree sloths Choloepus and Bradypus are the only remaining members of Folivora, a major xenarthran radiation that occupied a wide range of habitats in many parts of the western hemisphere during the Cenozoic, including both continents and the West Indies. Ancient DNA evidence has played only a minor role in folivoran systematics, as most sloths lived in places not conducive to genomic preservation. Here we utilize collagen sequence information, both separately and in combination with published mitochondrial DNA evidence, to assess the relationships of tree sloths and their extinct relatives. Results from phylogenetic analysis of these datasets differ substantially from morphology-based concepts: Choloepus groups with Mylodontidae, not Megalonychidae; Bradypus and Megalonyx pair together as megatherioids, while monophyletic Antillean sloths may be sister to all other folivorans. Divergence estimates are consistent with fossil evidence for mid-Cenozoic presence of sloths in the West Indies and an early Miocene radiation in South America

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Auditory objects are detected if they differ acoustically from the ongoing background. In simple cases, the appearance or disappearance of the object involves a transition in power, or frequency content, of the ongoing sound. However, it is more realistic that the background and object possess substantial non-stationary statistics, and the task is then to detect a transition in the pattern of ongoing statistics. How does the system detect and process such transitions? We use magnetoencephalography (MEG) to measure early auditory cortical responses to transitions between constant tones, regularly alternating, and randomly alternating tone-pip sequences. Such transitions embody key characteristics of natural auditory temporal edges. Our data demonstrate that the temporal dynamics and response morphology of the neural temporal-edge-detection processes depend in specific ways on the generalized nature of the edge (the context preceding and following the transition) and suggest that distinct neural substrates in core and non-core auditory cortex are recruited depending on the kind of computation (detection of a violation of regularity, vs. the acquisition of a new regularity rule) required to extract th

Stimulus Context Affects Auditory Cortical Responses to Changes in Interaural Correlation

cortical responses to changes in interaural correlation. J Neurophysio

Human auditory cortical processing of transitions between ‘order ’ and ‘disorder’

Sensitivity to changes in sound is important to auditory scene analysis and detection of the appearance of new objects in the environment. In this paper we describe two experiments that used Magnetoencephalography (MEG) to investigate the temporal dynamics of auditory cortical responses to changes in ongoin

AUDITORYAND VESTIBULAR SYSTEMS NEUROREPORT Auditory M50 and M100 responses to broadband noise: functional implications

The functional signi¢cance of the M50 and M100 auditory evoked ¢elds remains unclear. Here we report auditory evoked ¢eld data from three di¡erent studies employing wide-band noise stimuli.We ¢nd that, for the same stimuli, the strength of the M100, as well as its lateralization, are task-modulated.The M50, in contrast, shows three properties: It is dramatically more pronounced for nois

Left Ventricular Aneurysm Presenting as Bidirectional Ventricular Tachycardia

Bidirectional ventricular tachycardia is a rare form of ventricular arrhythmia, characterized by a changing of the mean QRS axis of 180 degrees. Digitalis toxicity is the most common cause of bidirectional ventricular tachycardia; other causes include myocarditis, aconite toxicity, metastatic cardiac tumor, myocardial infarction, and cardiac channelopathies. A 73-year-old male with hypertension and a pacemaker implanted for sick sinus syndrome presented with a complaint of substernal chest pressure for several days. He also stated he had had an episode of near syncope. The patient's physical examination was unremarkable; however, electrocardiogram demonstrated sustained bidirectional ventricular tachycardia. Echocardiogram showed severe anterior wall hypokinesis and an estimated ejection fraction of 35%, as well as an apical ventricular aneurysm. Electrophysiology study showed that the apical ventricular aneurysm was the site of the bidirectional arrhythmia. The patient was successfully treated with ventricular tachycardia ablation. This case is a unique example of a patient with bidirectional ventricular tachycardia originating from an apical left ventricular aneurysm that was treated successfully by ablation

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Neural dynamics of ignoring and attending i