Revision of the New Zealand gecko genus Hoplodactylus, with the description of a new species.

The New Zealand endemic gecko genus Hoplodactylus is revised. Two species are recognized: Hoplodactylus duvaucelii (Duméril & Bibron, 1836) from the North Island and some near-shore islands, and H. tohu n. sp., which was formerly widespread throughout the South Island but is presently restricted to some islands in the Cook Strait region. H. delcourti (Bauer & Russell, 1986) is retained in Hoplodactylus sensu lato in the interest of taxonomic stability, pending further research, but is probably neither congeneric nor from New Zealand.

Ancient mitochondrial genomes recovered from small vertebrate bones through minimally destructive DNA extraction: Phylogeography of the New Zealand gecko genus Hoplodactylus.

Methodological and technological improvements are continually revolutionizing the field of ancient DNA. Most ancient DNA extraction methods require the partial (or complete) destruction of finite museum specimens, which disproportionately impacts small or fragmentary subfossil remains, and future analyses. We present a minimally destructive ancient DNA extraction method optimized for small vertebrate remains. We applied this method to detect lost mainland genetic diversity in the large New Zealand diplodactylid gecko genus Hoplodactylus, which is presently restricted to predator-free island and mainland sanctuaries. We present the first mitochondrial genomes for New Zealand diplodactylid geckos, recovered from 19 modern, six historical/archival (1898-2011) and 16 Holocene Hoplodactylus duvaucelii sensu latu specimens, and one modern Woodworthia sp. specimen. No obvious damage was observed in post-extraction micro-computed tomography reconstructions. All "large gecko" specimens examined from extinct populations were found to be conspecific with extant Hoplodactylus species, suggesting their large relative size evolved only once in the New Zealand diplodactylid radiation. Phylogenetic analyses of Hoplodactylus samples recovered two genetically (and morphologically) distinct North and South Island clades, probably corresponding to distinct species. Finer phylogeographical structuring within Hoplodactylus spp. highlighted the impacts of Late Cenozoic biogeographical barriers, including the opening and closure of Pliocene marine straits, fluctuations in the size and suitability of glacial refugia, and eustatic sea-level change. Recent mainland extinction obscured these signals from the modern tissue-derived data. These results highlight the utility of minimally destructive DNA extraction in genomic analyses of less well studied small vertebrate taxa, and the conservation of natural history collections.

Application of palaeogenetic techniques to historic mollusc shells reveals phylogeographic structure in a New Zealand abalone.

Natural history collections worldwide contain a plethora of mollusc shells. Recent studies have detailed the sequencing of DNA extracted from shells up to thousands of years old and from various taphonomic and preservational contexts. However, previous approaches have largely addressed methodological rather than evolutionary research questions. Here, we report the generation of DNA sequence data from mollusc shells using such techniques, applied to Haliotis virginea Gmelin, 1791, a New Zealand abalone, in which morphological variation has led to the recognition of several forms and subspecies. We successfully recovered near-complete mitogenomes from 22 specimens including 12 dry-preserved shells up to 60 years old. We used a combination of palaeogenetic techniques that have not previously been applied to shell, including DNA extraction optimized for ultra-short fragments and hybridization-capture of single-stranded DNA libraries. Phylogenetic analyses revealed three major, well-supported clades comprising samples from: (1) The Three Kings Islands; (2) the Auckland, Chatham and Antipodes Islands; and (3) mainland New Zealand and Campbell Island. This phylogeographic structure does not correspond to the currently recognized forms. Critically, our nonreliance on freshly collected or ethanol-preserved samples enabled inclusion of topotypes of all recognized subspecies as well as additional difficult-to-sample populations. Broader application of these comparatively cost-effective and reliable methods to modern, historical, archaeological and palaeontological shell samples has the potential to revolutionize invertebrate genetic research.

Splitting of the magnetic encephalogram into «brain¼ and «non-brain¼ physiological signals based on the joint analysis of frequency-pattern functional tomograms and magnetic resonance images.

The article considers the problem of dividing the encephalography data into two time series, that generated by the brain and that generated by other electrical sources located in the human head. The magnetic encephalograms and magnetic resonance images of the head were recorded in the Center for Neuromagnetism at NYU Grossman School of Medicine. Data obtained at McGill University and Montreal University were also used. Recordings were made in a magnetically shielded room and the gradiometers were designed to suppress external noise, making it possible to eliminate them from the data analysis. Magnetic encephalograms were analyzed by the method of functional tomography, based on the Fourier transform and on the solution of inverse problem for all frequencies. In this method, one spatial position is assigned to each frequency component. Magnetic resonance images of the head were evaluated to annotate the space to be included in the analysis. The included space was divided into two parts: «brain¼ and «non-brain¼. The frequency components were classified by the feature of their inclusion in one or the other part. The set of frequencies, designated as «brain¼, represented the partial spectrum of the brain signal, while the set of frequencies designated as «non-brain¼, represented the partial spectrum of the physiological noise produced by the head. Both partial spectra shared the same frequency band. From the partial spectra, a time series of the «brain¼ area signal and «non-brain¼ area head noise were reconstructed. Summary spectral power of the signal was found to be ten times greater than the noise. The proposed method makes it possible to analyze in detail both the signal and the noise components of the encephalogram and to filter the magnetic encephalogram.

Noninvasive muscle activity imaging using magnetography.

A spectroscopic paradigm has been developed that allows the magnetic field emissions generated by the electrical activity in the human body to be imaged in real time. The growing significance of imaging modalities in biology is evident by the almost exponential increase of their use in research, from the molecular to the ecological level. The method of analysis described here allows totally noninvasive imaging of muscular activity (heart, somatic musculature). Such imaging can be obtained without additional methodological steps such as the use of contrast media.

Differential Modulation of Rhythmic Brain Activity in Healthy Adults by a T-Type Calcium Channel Blocker: An MEG Study.

1-octanol is a therapeutic candidate for disorders involving the abnormal activation of the T-type calcium current since it blocks this current specifically. Such disorders include essential tremor and a group of neurological and psychiatric disorders resulting from thalamocortical dysrhythmia (TCD). For example, clinically, the observable phenotype in essential tremor is the tremor itself. The differential diagnostic of TCD is not based only on clinical signs and symptoms. Rather, TCD incorporates an electromagnetic biomarker, the presence of abnormal thalamocortical low frequency brain oscillations. The effect of 1-octanol on brain activity has not been tested. As a preliminary step to such a TCD study, we examined the short-term effects of a single dose of 1-octanol on resting brain activity in 32 healthy adults using magnetoencephalograpy. Visual inspection of baseline power spectra revealed that the subjects fell into those with strong low frequency activity (set 2, n = 11) and those without such activity, but dominated by an alpha peak (set 1, n = 22). Cross-validated linear discriminant analysis, using mean spectral density (MSD) in nine frequency bands as predictors, found overall that 82.5% of the subjects were classified as determined by visual inspection. The effect of 1-octanol on the MSD in narrow frequency bands differed between the two subject groups. In set 1 subjects the MSD increased in the 4.5-6.5Hz and 6.5-8.5 Hz bands. This was consistent with a widening of the alpha peak toward lower frequencies. In the set two subjects the MSD decrease in the 2.5-4.5 Hz and 4.5-6.5 Hz bands. This decreased power is consistent with the blocking effect of 1-octanol on T-type calcium channels. The subjects reported no adverse effects of the 1-octanol. Since stronger low frequency activity is characteristic of patients with TCD, 1-octanol and other T-type calcium channel blockers are good candidates for treatment of this group of disorders following a placebo-controlled study.

Reconstruction of human brain spontaneous activity based on frequency-pattern analysis of magnetoencephalography data.

A new method for the analysis and localization of brain activity has been developed, based on multichannel magnetic field recordings, over minutes, superimposed on the MRI of the individual. Here, a high resolution Fourier Transform is obtained over the entire recording period, leading to a detailed multi-frequency spectrum. Further analysis implements a total decomposition of the frequency components into functionally invariant entities, each having an invariant field pattern localizable in recording space. The method, addressed as functional tomography, makes it possible to find the distribution of magnetic field sources in space. Here, the method is applied to the analysis of simulated data, to oscillating signals activating a physical current dipoles phantom, and to recordings of spontaneous brain activity in 10 healthy adults. In the analysis of simulated data, 61 dipoles are localized with 0.7 mm precision. Concerning the physical phantom the method is able to localize three simultaneously activated current dipoles with 1 mm precision. Spatial resolution 3 mm was attained when localizing spontaneous alpha rhythm activity in 10 healthy adults, where the alpha peak was specified for each subject individually. Co-registration of the functional tomograms with each subject's head MRI localized alpha range activity to the occipital and/or posterior parietal brain region. This is the first application of this new functional tomography to human brain activity. The method successfully provides an overall view of brain electrical activity, a detailed spectral description and, combined with MRI, the localization of sources in anatomical brain space.

Enhanced synaptic transmission at the squid giant synapse by artificial seawater based on physically modified saline.

Superfusion of the squid giant synapse with artificial seawater (ASW) based on isotonic saline containing oxygen nanobubbles (RNS60 ASW) generates an enhancement of synaptic transmission. This was determined by examining the postsynaptic response to single and repetitive presynaptic spike activation, spontaneous transmitter release, and presynaptic voltage clamp studies. In the presence of RNS60 ASW single presynaptic stimulation elicited larger postsynaptic potentials (PSP) and more robust recovery from high frequency stimulation than in control ASW. Analysis of postsynaptic noise revealed an increase in spontaneous transmitter release with modified noise kinetics in RNS60 ASW. Presynaptic voltage clamp demonstrated an increased EPSP, without an increase in presynaptic ICa(++) amplitude during RNS60 ASW superfusion. Synaptic release enhancement reached stable maxima within 5-10 min of RNS60 ASW superfusion and was maintained for the entire recording time, up to 1 h. Electronmicroscopic morphometry indicated a decrease in synaptic vesicle density and the number at active zones with an increase in the number of clathrin-coated vesicles (CCV) and large endosome-like vesicles near junctional sites. Block of mitochondrial ATP synthesis by presynaptic injection of oligomycin reduced spontaneous release and prevented the synaptic noise increase seen in RNS60 ASW. After ATP block the number of vesicles at the active zone and CCV was reduced, with an increase in large vesicles. The possibility that RNS60 ASW acts by increasing mitochondrial ATP synthesis was tested by direct determination of ATP levels in both presynaptic and postsynaptic structures. This was implemented using luciferin/luciferase photon emission, which demonstrated a marked increase in ATP synthesis following RNS60 administration. It is concluded that RNS60 positively modulates synaptic transmission by up-regulating ATP synthesis, thus leading to synaptic transmission enhancement.

Imaging of thalamocortical dysrhythmia in neuropsychiatry.

Abnormal brain activity dynamics, in the sense of a thalamocortical dysrhythmia (TCD), has been proposed as the underlying mechanism for a subset of disorders that bridge the traditional delineations of neurology and neuropsychiatry. In order to test this proposal from a psychiatric perspective, a study using magnetoencephalography (MEG) was implemented in subjects with schizophrenic spectrum disorder (n = 14), obsessive-compulsive disorder (n = 10), or depressive disorder (n = 5) and in control individuals (n = 18). Detailed CNS electrophysiological analysis of these patients, using MEG, revealed the presence of abnormal theta range spectral power with typical TCD characteristics, in all cases. The use of independent component analysis and minimum-norm-based methods localized such TCD to ventromedial prefrontal and temporal cortices. The observed mode of oscillation was spectrally equivalent but spatially distinct from that of TCD observed in other related disorders, including Parkinson's disease, central tinnitus, neuropathic pain, and autism. The present results indicate that the functional basis for much of these pathologies may relate most fundamentally to the category of calcium channelopathies and serve as a model for the cellular substrate for low-frequency oscillations present in these psychiatric disorders, providing a basis for therapeutic strategies.

Oral administration of pharmacologically active substances to squid: a methodological description.

The squid giant synapse is a well-defined experimental preparation for the study of ligand-dependant synaptic transmission. Its large size gives direct experimental access to both presynaptic and postsynaptic junctional elements, allowing direct optical, biophysical, and electrophysiological analysis of depolarization-release coupling. However, this important model has not been utilized in pharmacological studies, other than those implementable acutely in the in vitro condition. A method is presented for oral administration of bioactive substances to living squid. Electrophysiological characterization and direct determination of drug absorption into the nervous system demonstrate the administration method described here to be appropriate for pharmacological research.

Intravascular Neural Interface with Nanowire Electrode.

A minimally invasive electrical recording and stimulating technique capable of simultaneously monitoring the activity of a significant number (e.g., 10(3) to 10(4)) of neurons is an absolute prerequisite in developing an effective brain-machine interface. Although there are many excellent methodologies for recording single or multiple neurons, there has been no methodology for accessing large numbers of cells in a behaving experimental animal or human individual. Brain vascular parenchyma is a promising candidate for addressing this problem. It has been proposed [1, 2] that a multitude of nanowire electrodes introduced into the central nervous system through the vascular system to address any brain area may be a possible solution. In this study we implement a design for such microcatheter for ex vivo experiments. Using Wollaston platinum wire, we design a submicron-scale electrode and develop a fabrication method. We then evaluate the mechanical properties of the electrode in a flow when passing through the intricacies of the capillary bed in ex vivo Xenopus laevis experiments. Furthermore, we demonstrate the feasibility of intravascular recording in the spinal cord of Xenopus laevis.

Long-term effects of microgravity on the swimming behaviour of young rats.

The postnatal development of sensory systems has been shown in studies over the last four decades to be influenced by experience during critical periods of development. We report here that similar experience-dependent development can be observed in the swimming behaviour of young rats reared from postnatal day 14 (P14) to P30 in the reduced gravitational field of low earth orbit. Animals flown in space when placed in the water on the day of landing maintained their head and forelimbs in a balanced posture. However, until the animals began to swim, their hindquarters showed little lateral postural control resulting in rotation about the longitudinal axis (60 degrees+/-4 deg). Such results suggest an 'unlinking' of postural control of the forequarters from the hindquarters in the early hours after landing. Similar instability seen in animals age-matched to the day of launch (97+/-7 deg) and in ground control animals (9+/-3 deg) was corrected within one or two rotations, even in the absence of swimming. Animals flown in space began to swim sooner after being placed in the water, and the duration of swimming strokes was shorter than in control animals. Motion analysis revealed a difference in the swimming style on landing day. In flight animals, the knee joint was more flexed throughout the stroke, there was a narrower range of movement, and the linear velocity of the tip of the foot was faster throughout most of the stroke than in age-matched control animals. Thus, posture in the water as well as swimming speed and style were altered in the animals flown in space. Some of these characteristics persisted for as long as the animals were followed (30 days). These included the short pre-swimming interval and short stroke duration in flight animals. These findings clearly show that an altered gravitational field influences the postnatal development of motor function. The nature of the differences between animals reared in space for 16 days and those remaining on the ground reflects an adaptation of the flight animals to the microgravity environment. The data suggest that the most fundamental of these adaptations is a resetting of the basic motor rhythm to a higher frequency.

The effects of microgravity on the development of surface righting in rats.

The active interaction of neonatal animals with their environment has been shown to be a decisive factor in the postnatal development of sensory systems, which demonstrates a critical period in their maturation. The direct demonstration of such a dependence on the rearing environment has not been demonstrated for motor system function. Nor has the role of gravity in mammalian motor system development been investigated. Here we report the results of two space flight missions examining the effect of removing gravity on the development of surface righting. Since the essential stimulus that drives this synergy, gravitation, was missing, righting did not occur while the animals were in the microgravity environment. We hypothesize that this absence of contextual motor experience arrested the maturation of the motor tactics for surface righting. Such effects were permanent in rats spending 16 days (from postnatal day (P), P14 to P30), but were transient in animals spending nine days (from P15 to P24) in microgravity. Thus, active, contextual interaction with the environment during a critical period of development is necessary for the postnatal maturation of motor tactics as exemplified by surface righting, and such events must occur within a particular time period. Further, Earth's gravitational field is not assumed by the developing motor system. Rather, postnatal motor system development is appropriate to the gravitational field in which the animal is reared.