The rodent vomeronasal organ (VNO) mediates the regulation of species-specific and interspecies social behaviors. We have used gene targeting to examine the role of the G protein Gαo, encoded by the gene Gnao1, in vomeronasal function. We used the Cre-loxP system to delete Gαo in those cells that express olfactory marker protein, which includes all vomeronasal sensory neurons of the basal layer of the VNO sensory epithelium. Using electrophysiology and calcium imaging, we show that the conditional null mice exhibit strikingly reduced sensory responses in V2R receptor-expressing vomeronasal sensory neurons to specific molecular cues, including MHC1 antigens, major urinary proteins, and exocrine gland-secreting peptide. Gαo is also vital for vomeronasal sensing of two Nformylated mitochondrially encoded peptides derived from NADH dehydrogenase 1. Furthermore, we show that Gαo is an essential requirement for the display of male-male territorial aggression as well as maternal aggression in mice. Finally, we show that Gαo-dependent maternal aggression can be induced by major urinary proteins. These cellular and behavioral phenotypes identify Gαo as the primary G-protein α-subunit mediating the detection of peptide and protein pheromones by sensory neurons of the VNO.formyl peptide receptor | olfaction | peptide detection | Trpc2 | social recognition T he mammalian olfactory system comprises a complex array of subsystems, but the functional significance of this organization remains unclear (1). The mouse vomeronasal organ (VNO)-which has attracted specific attention because of its vital role in social communication (2, 3)-consists of at least two distinct layers containing apical (superficial) and basal (deep) populations of vomeronasal sensory neurons (VSNs), which project their axons to discrete regions of the accessory olfactory bulb (AOB) (4-6). These VSN populations are characterized by differential expression of heterotrimeric G proteins and G proteincoupled receptors (GPCRs): apical VSNs express Gαi2 and members of the V1R family of vomeronasal GPCRs (7), whereas basal VSNs express Gαo and members of the V2R receptor family (8-10). VSNs of both layers express the transient receptor potential channel Trpc2 (11-13). Whether these two VNO subsystems function in relative isolation, each specialized to control a distinct subset of social behaviors, or whether they work in a cooperative and integrative manner remains unclear.A series of gene deletion studies has revealed an obligate requirement of Trpc2 (12-14) and at least some V1Rs (15, 16) and V2Rs (17, 18) for the generation of sensory responses in VSN populations. Together, these studies support a model of VSN signaling in which receptor occupancy, through G-protein coupling, causes activation of phospholipase C (PLC) that, in turn, leads to the activation of a Ca 2+ -permeable, Trpc2-dependent cation channel (19). Ca 2+ entry through this channel mediates both negative and positive VSN feedback regulation through calmodulin-dependent sensory adaptation and down...

OBJECT Evidence in support of hemispherectomy stems from a multitude of retrospective studies illustrating individual institutions' experience. A systematic review of this topic, however, is lacking in the literature. METHODS A systematic review of hemispherectomy for the treatment of refractory epilepsy available up to October 2013 was performed using the following inclusion criteria: reports of a total of 10 or more patients in the pediatric age group (≤ 20 years) undergoing hemispherectomy, seizure outcome reported after a minimum follow-up of 1 year after the initial procedure, and description of the type of hemispherectomy. Only the most recent paper from institutions that published multiple papers with overlapping study periods was included. Two reviewers independently applied the inclusion criteria and extracted all the data. RESULTS Twenty-nine studies with a total of 1161 patients met the inclusion criteria. Seizure outcome was available for 1102 patients, and the overall rate of seizure freedom at the last follow-up was 73.4%. Sixteen studies (55.2%) exclusively reported seizure outcomes of a single type of hemispherectomy. There was no statistically significant difference in seizure outcome and type of hemispherectomy (p = 0.737). Underlying etiology was reported for 85.4% of patients with documented seizure outcome, and the overall distribution of acquired, developmental, and progressive etiologies was 30.5%, 40.7%, and 28.8%, respectively. Acquired and progressive etiologies were associated with significantly higher seizure-free rates than developmental etiologies (p < 0.001). Twenty of the 29 studies (69%) reported complications. The overall rate of hydrocephalus requiring CSF diversion was 14%. Mortality within 30 days was 2.2% and was not statistically different between types of hemispherectomy (p = 0.787). CONCLUSIONS Hemispherectomy is highly effective for treating refractory epilepsy in the pediatric age group, particularly for acquired and progressive etiologies. While the type of hemispherectomy does not have any influence on seizure outcome, hemispherotomy procedures are associated with a more favorable complication profile.

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Object Tectal plate gliomas are generally low-grade astrocytomas with favorable prognosis, and observation of the lesion and management of hydrocephalus remain the mainstay of treatment. Methods A cohort of patients with tectal plate gliomas at 2 academic institutions was retrospectively reviewed. Results Forty-four patients with a mean age of 10.2 years who harbored tectal plate gliomas were included in the study. The mean clinical and radiological follow-up was 7.6 ± 3.3 years (median 7.9 years, range 1.5–14.7 years) and 6.5 ± 3.1 years (median 6.5 years, range 1.1–14.7 years), respectively. The most frequent intervention was CSF diversion (81.8% of patients) followed by biopsy (11.4%), radiotherapy (4.5%), chemotherapy (4.5%), and resection (2.3%). On MR imaging tectal plate gliomas most commonly showed T1-weighted isointensity (71.4%), T2-weighted hyperintensity (88.1%), and rarely enhanced (19%). The initial mean volume was 1.6 ± 2.2 cm3 and it increased to 2.0 ± 4.4 cm3 (p = 0.628) at the last follow-up. Frontal and occipital horn ratio (FOHR) and third ventricular width statistically decreased over time (p < 0.001 and p < 0.05, respectively). Conclusions The authors' results support existing evidence that tectal plate gliomas frequently follow a benign clinical and radiographic course and rarely require any intervention beyond management of associated hydrocephalus.