GluD1, linked to schizophrenia, controls the burst firing of dopamine neurons

Human mutations of the GRID1 gene encoding the orphan delta1 glutamate receptor-channel (GluD1) are associated with schizophrenia but the explicit role of GluD1 in brain circuits is unknown. Based on the known function of its paralog GluD2 in cerebellum, we searched for a role of GluD1 in slow glutamatergic transmission mediated by metabotropic receptor mGlu1 in midbrain dopamine neurons, whose dysfunction is a hallmark of schizophrenia. We found that an mGlu1 agonist elicits a slow depolarizing current in HEK cells co-expressing mGlu1 and GluD1, but not in cells expressing mGlu1 or GluD1 alone. This current is abolished by additional co-expression of a dominant-negative GluD1 dead pore mutant. We then characterized mGlu1-dependent currents in dopamine neurons from midbrain slices. Both the agonist-evoked and the slow postsynaptic currents are abolished by expression of the dominant-negative GluD1 mutant, pointing to the involvement of native GluD1 channels in these currents. Likewise, both mGlu1-dependent currents are suppressed in GRID1 knockout mice, which reportedly display endophenotypes relevant for schizophrenia. It is known that mGlu1 activation triggers the transition from tonic to burst firing of dopamine neurons, which signals salient stimuli and encodes reward prediction. In vivo recordings of dopamine neurons showed that their spontaneous burst firing is abolished in GRID1 knockout mice or upon targeted expression of the dominant-negative GluD1 mutant in wild-type mice. Our results de-orphanize GluD1, unravel its key role in slow glutamatergic transmission and provide insights into how GRID1 gene alterations can lead to dopaminergic dysfunctions in schizophrenia

The frequency-dependent Wright-Fisher model: diffusive and non-diffusive approximations

We study a class of processes that are akin to the Wright-Fisher model, with transition probabilities weighted in terms of the frequency-dependent fitness of the population types. By considering an approximate weak formulation of the discrete problem, we are able to derive a corresponding continuous weak formulation for the probability density. Therefore, we obtain a family of partial differential equations (PDE) for the evolution of the probability density, and which will be an approximation of the discrete process in the joint large population, small time-steps and weak selection limit. If the fitness functions are sufficiently regular, we can recast the weak formulation in a more standard formulation, without any boundary conditions, but supplemented by a number of conservation laws. The equations in this family can be purely diffusive, purely hyperbolic or of convection-diffusion type, with frequency dependent convection. The particular outcome will depend on the assumed scalings. The diffusive equations are of the degenerate type; using a duality approach, we also obtain a frequency dependent version of the Kimura equation without any further assumptions. We also show that the convective approximation is related to the replicator dynamics and provide some estimate of how accurate is the convective approximation, with respect to the convective-diffusion approximation. In particular, we show that the mode, but not the expected value, of the probability distribution is modelled by the replicator dynamics. Some numerical simulations that illustrate the results are also presented

Advertisement and aggressive calls of Ischnocnema oea (Heyer, 1984) (Anura, Brachycephalidae)

Hepp, Fabio, Canedo, Clarissa (2013): Advertisement and aggressive calls of Ischnocnema oea (Heyer, 1984) (Anura, Brachycephalidae). Zootaxa 3710 (2): 197-199, DOI: 10.11646/zootaxa.3710.2.

FIGURE 1 in Advertisement and aggressive calls of Ischnocnema oea (Heyer, 1984) (Anura, Brachycephalidae)

FIGURE 1. Ischnocnema oea: spectrogram and power spectrum with window function Hann, amplitude logarithmic, window size 512 samples, overlap 99%. (A) Oscillogram, (B) spectrogram and (C) power spectrum of one advertisement call. (D) Oscillogram, (E) spectrogram and (F) power spectrum of one aggressive call.Published as part of <i>Hepp, Fabio & Canedo, Clarissa, 2013, Advertisement and aggressive calls of Ischnocnema oea (Heyer, 1984) (Anura, Brachycephalidae), pp. 197-199 in Zootaxa 3710 (2)</i> on page 198, DOI: 10.11646/zootaxa.3710.2.6, <a href="http://zenodo.org/record/10099463">http://zenodo.org/record/10099463</a&gt

First record of Scinax tripui Lourenço, Nascimento and Pires, 2010 (Amphibia: Anura: Hylidae) from Espírito Santo state, Brazil

Scinax tripui is a medium sized frog that belongs to the Scinax catharinae clade. We provide a new record of Scinax tripui from Serra de Torres, Espírito Santo state, southeastern Brazil. This is the first record outside the specie’s type locality (Ouro Preto, Minas Gerais) and the first record from the state of Espírito Santo

Taxonomic status and redescription of Flectonotus ulei (Anura: Hemiphractidae), with a key for the species of Fritziana

Based on preserved specimens from the states of São Paulo and Rio de Janeiro, Flectonotus ulei Miranda-Ribeiro, 1926 is resurrected from its synonymy with Flectonotus fissilis (Miranda-Ribeiro, 1920) and is redescribed. Analysis of osteological characters and brood pouch structure confirms that F. ulei belongs to Fritziana. The species is small for the genus (snout-vent length in males, 19.2-26.9 mm, n = 2; in females, 20.3-21 mm, n = 4) and was found in bromeliads. Flectonotus ulei is characterized by dorsal pattern consisting of interorbital pentagon or hexagon-shaped mark delimited by heavy dark line, diameter of tympanum smaller than that of disc of third digit, and a brood pouch covering the eggs dorsally except for a narrow longitudinal slit; eggs arranged in rosette

Taxonomic status and redescription of Flectonotus ulei (Anura: Hemiphractidae), with a key for species of Fritziana

Based on preserved specimens from the states of São Paulo and Rio de Janeiro, Flectonotus ulei Miranda-Ribeiro, 1926 is resurrected from its synonymy with Flectonotus fissilis (Miranda-Ribeiro, 1920) and is redescribed. Analysis of osteological characters and brood pouch structure confirms that F. ulei belongs to Fritziana. The species is small for the genus (snout-vent length in males, 19.2-26.9 mm, n = 2; in females, 20.3-21 mm, n = 4) and was found in bromeliads. Flectonotus ulei is characterized by dorsal pattern consisting of interorbital pentagon or hexagon-shaped mark delimited by heavy dark line, diameter of tympanum smaller than that of disc of third digit, and a brood pouch covering the eggs dorsally except for a narrow longitudinal slit; eggs arranged in rosette

Automated and Quantitative Assessment of Tactile Mislocalization After Stroke

Topesthesia, the recognition of tactile stimulation location on the skin, can be severely affected by neurological injuries, such as stroke. Despite topesthesia being crucial for manipulating objects and interacting with the environment during activities of daily living, deficits cannot be quantitatively captured with current clinical assessments and are, as a consequence, not well-understood. The present work describes a novel automated assessment tool for tactile mislocalization in neurological patients with somatosensory deficits. We present two cases of ischemic stroke patients, describe their tactile localization deficits with the automated assessment, and compare the results to a standard manual clinical assessment. Using the automated assessment tool, it was possible to identify, locate, precisely quantify, and depict the patients' deficits in topesthesia. In comparison, the clinical assessment was not sensitive enough and some deficits would remain undetected due to ceiling effects. In addition, an MRI structural analysis of the lesion supported the existence of somatosensory deficits. This novel and quantitative assessment may not only help to raise awareness of the implications of deficits in topesthesia, but would also allow monitoring recovery throughout the rehabilitation process, informing treatment design, and objectively evaluating treatment efficacy