Time and Origin of Cichlid Colonization of the Lower Congo Rapids

Most freshwater diversity is arguably located in networks of rivers and streams, but, in contrast to lacustrine systems riverine radiations, are largely understudied. The extensive rapids of the lower Congo River is one of the few river stretches inhabited by a locally endemic cichlid species flock as well as several species pairs, for which we provide evidence that they have radiated in situ. We use more that 2,000 AFLP markers as well as multilocus sequence datasets to reconstruct their origin, phylogenetic history, as well as the timing of colonization and speciation of two Lower Congo cichlid genera, Steatocranus and Nanochromis. Based on a representative taxon sampling and well resolved phylogenetic hypotheses we demonstrate that a high level of riverine diversity originated in the lower Congo within about 5 mya, which is concordant with age estimates for the hydrological origin of the modern lower Congo River. A spatial genetic structure is present in all widely distributed lineages corresponding to a trisection of the lower Congo River into major biogeographic areas, each with locally endemic species assemblages. With the present study, we provide a phylogenetic framework for a complex system that may serve as a link between African riverine cichlid diversity and the megadiverse cichlid radiations of the East African lakes. Beyond this we give for the first time a biologically estimated age for the origin of the lower Congo River rapids, one of the most extreme freshwater habitats on earth

A Functional Role for Modality-Specific Perceptual Systems in Conceptual Representations

Theories of embodied cognition suggest that conceptual processing relies on the same neural resources that are utilized for perception and action. Evidence for these perceptual simulations comes from neuroimaging and behavioural research, such as demonstrations of somatotopic motor cortex activations following the presentation of action-related words, or facilitation of grasp responses following presentation of object names. However, the interpretation of such effects has been called into question by suggestions that neural activation in modality-specific sensorimotor regions may be epiphenomenal, and merely the result of spreading activations from “disembodied”, abstracted, symbolic representations. Here, we present two studies that focus on the perceptual modalities of touch and proprioception. We show that in a timed object-comparison task, concurrent tactile or proprioceptive stimulation to the hands facilitates conceptual processing relative to control stimulation. This facilitation occurs only for small, manipulable objects, where tactile and proprioceptive information form part of the multimodal perceptual experience of interacting with such objects, but facilitation is not observed for large, nonmanipulable objects where such perceptual information is uninformative. Importantly, these facilitation effects are independent of motor and action planning, and indicate that modality-specific perceptual information plays a functionally constitutive role in our mental representations of objects, which supports embodied assumptions that concepts are grounded in the same neural systems that govern perception and action

A review of the systematic biology of fossil and living bony-tongue fishes, Osteoglossomorpha (Actinopterygii: Teleostei)

The bony-tongue fishes, Osteoglossomorpha, have been the focus of a great deal of morphological, systematic, and evolutionary study, due in part to their basal position among extant teleostean fishes. This group includes the mooneyes (Hiodontidae), knifefishes (Notopteridae), the abu (Gymnarchidae), elephantfishes (Mormyridae), arawanas and pirarucu (Osteoglossidae), and the African butterfly fish (Pantodontidae). This morphologically heterogeneous group also has a long and diverse fossil record, including taxa from all continents and both freshwater and marine deposits. The phylogenetic relationships among most extant osteoglossomorph families are widely agreed upon. However, there is still much to discover about the systematic biology of these fishes, particularly with regard to the phylogenetic affinities of several fossil taxa, within Mormyridae, and the position of Pantodon. In this paper we review the state of knowledge for osteoglossomorph fishes. We first provide an overview of the diversity of Osteoglossomorpha, and then discuss studies of the phylogeny of Osteoglossomorpha from both morphological and molecular perspectives, as well as biogeographic analyses of the group. Finally, we offer our perspectives on future needs for research on the systematic biology of Osteoglossomorpha

Chronic coffee consumption and striatal DAT-SPECT findings in Parkinson’s disease

Coffee may interfere with the dopaminergic transmission, and this action would possibly enhance motor activity and exert an antidyskinetic effect in Parkinsonâs disease (PD). This study aimed to see whether coffee habit could be associated with change in striatal dopamine active transporter (DAT)-single photon emission computed tomography (SPECT) imaging in PD. A total of 83 PD patients (71 current coffee drinkers and 12 never drinkers) underwent a DAT-SPECT study, using [123I]FP-CIT as radionuclide. Socio-demographic and clinical information as well as smoking habit was collected at the time of imaging acquisition. The Unified Parkinsonâs Disease Rating Scale part III was used to evaluate disease severity. On multivariable analysis, chronic coffee consumption was not associated with any significant change in striatal uptake of the radionuclide. However, the number of years patients drunk coffee was correlated with a significant increase in age at PD onset (p < 0.001). Confirming a previous report, current cigarette smoking was associated with a reduction of radionuclide uptake in putamen and caudate (p < 0.001)