Functional mapping of the auditory midbrain during mate call reception

We examined patterns of neural activity as assayed by changes in gene expression to localize representation of acoustic mating signals in the auditory midbrain of frogs. We exposed wild-caught male Physalaemus pustulosus to conspecific mating calls that vary in their behavioral salience, nonsalient mating calls, or no sound. We measured expression of the immediate early gene egr-1 (also called ZENK, zif268, NGFI-A, and krox-24) throughout the torus semicircularis, the auditory midbrain homolog of the inferior colliculus. Differential egr-1 induction in response to the acoustic stimuli occurred in the laminar, midline, and principal nuclei of the torus semicircularis, whereas the ventral region did not show significant effects of stimulus. The laminar nucleus differentially responded to conspecific mating calls compared with nonsalient mating calls, whereas the midline and principal nuclei responded preferentially to one of two conspecific calls. These responses were not explained by simple acoustic properties of the stimuli, and they demonstrate a functional heterogeneity of auditory processing of complex biological signals within the frog midbrain. Moreover, using analyses that assess the ability of the torus semicircularis as a whole to discriminate among acoustic stimuli, we found that activity patterns in the four regions together provide more information about biologically relevant acoustic stimuli than activity in any single region

Mating patterns and post-mating isolation in three cryptic species of the Engystomops petersi species complex

This research was funded by a National Science Foundation IOS-0940466 grant to KH and a UNESCO-L’Oreal-CONCYTEC 001-2009-L’Oreal fellowship to PAT. Laboratory work was funded by grants from the Secretarı´a de Educacio´n Superior, Ciencia, Tecnologı´a e Innovación (SENESCYT, Arca de Noe´ Initiative) and a Pontificia Universidad Católica del Ecuador (PUCE-DGA) grant to SRR. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte

Association between a genetic variant in the serotonin transporter gene (<it>SLC6A4</it>) and suicidal behavior in patients with schizophrenia

<p>Abstract</p> <p>Background</p> <p>The serotonin (5-hydroxytryptamin; 5-HT) system has a central role in the circuitry of cognition and emotions. Multiple lines of evidence suggest that genetic variation in the serotonin transporter gene (<it>SLC6A4</it>; <it>5-HTT</it>) is associated with schizophrenia and suicidal behavior. In this study, we wanted to elucidate whether <it>SLC6A4</it> variations is involved in attempted suicide among patients with schizophrenia in a Scandinavian case–control sample.</p> <p>Methods</p> <p>Patients diagnosed with schizophrenia from three Scandinavian samples were assessed for presence or absence of suicide attempts, based on record reviews and interview data. Seven <it>SLC6A4</it> single nucleotide polymorphisms (SNPs) were genotyped in 837 schizophrenia patients and 1,473 control individuals. Association analyses and statistical evaluations were performed with the program UNPHASED (version 3.0.9).</p> <p>Results</p> <p>We observed an allele association between the SNP rs16965628, located in intron one of <it>SLC6A4</it>, and attempted suicide (adjusted p-value 0.01), among patients with schizophrenia. No association was found to a diagnosis of schizophrenia, when patients were compared to healthy control individuals.</p> <p>Conclusion</p> <p>The gene <it>SLC6A4</it> appears to be involved in suicidal ideation among patients with schizophrenia. Independent replication is needed before more firm conclusions can be drawn.</p