GluN3A excitatory glycine receptors control adult cortical and amygdalar circuits.

GluN3A is an atypical glycine-binding subunit of NMDA receptors (NMDARs) whose actions in the brain are mostly unknown. Here, we show that the expression of GluN3A subunits controls the excitability of mouse adult cortical and amygdalar circuits via an unusual signaling mechanism involving the formation of excitatory glycine GluN1/GluN3A receptors (eGlyRs) and their tonic activation by extracellular glycine. eGlyRs are mostly extrasynaptic and reside in specific neuronal populations, including the principal cells of the basolateral amygdala (BLA) and SST-positive interneurons (SST-INs) of the neocortex.

NMDARs in granule cells contribute to parallel fiber-Purkinje cell synaptic plasticity and motor learning.

Long-term synaptic plasticity is believed to be the cellular substrate of learning and memory. Synaptic plasticity rules are defined by the specific complement of receptors at the synapse and the associated downstream signaling mechanisms. In young rodents, at the cerebellar synapse between granule cells (GC) and Purkinje cells (PC), bidirectional plasticity is shaped by the balance between transcellular nitric oxide (NO) driven by presynaptic -methyl-D-aspartate receptor (NMDAR) activation and postsynaptic calcium dynamics.

Triheteromeric NMDA receptors: from structure to synaptic physiology.

N-methyl-D-aspartate receptors (NMDARs) are glutamate-gated ion channels that play crucial roles in brain development and synaptic plasticity. They are also therapeutic targets of interest since their dysfunction is associated with multiple neurological and psychiatric disorders. , NMDARs exist as multiple subtypes that differ in their subunit composition, anatomical distribution, functional properties, as well as signaling capacities.

Reallocation of Olfactory Cajal-Retzius Cells Shapes Neocortex Architecture.

The neocortex undergoes extensive developmental growth, but how its architecture adapts to expansion remains largely unknown. Here, we investigated how early born Cajal-Retzius (CR) neurons, which regulate the assembly of cortical circuits, maintain a dense superficial distribution in the growing neocortex. We found that CR cell density is sustained by an activity-dependent importation of olfactory CR cells, which migrate into the neocortex after they have acted as axonal guidepost cells in the olfactory system.

Burst-Dependent Bidirectional Plasticity in the Cerebellum Is Driven by Presynaptic NMDA Receptors.

Numerous studies have shown that cerebellar function is related to the plasticity at the synapses between parallel fibers and Purkinje cells. How specific input patterns determine plasticity outcomes, as well as the biophysics underlying plasticity of these synapses, remain unclear. Here, we characterize the patterns of activity that lead to postsynaptically expressed LTP using both in vivo and in vitro experiments.

Properties and molecular identity of NMDA receptors at synaptic and non-synaptic inputs in cerebellar molecular layer interneurons.

N-methyl-D-aspartate receptors (NMDARs) in cerebellar molecular layer interneurons (MLIs) are expressed and activated in unusual ways: at parallel fibre (PF) synapses they are only recruited by repetitive stimuli, suggesting an extrasynaptic location, whereas their activation by climbing fibre is purely mediated by spillover. NMDARs are thought to play an important role in plasticity at different levels of the cerebellar circuitry. Evaluation of the location, functional properties and physiological roles of NMDARs will be facilitated by knowledge of the NMDAR isoforms recruited.

Zinc dynamics and action at excitatory synapses.

Decades after the discovery that ionic zinc is present at high levels in glutamatergic synaptic vesicles, where, when, and how much zinc is released during synaptic activity remains highly controversial. Here we provide a quantitative assessment of zinc dynamics in the synaptic cleft and clarify its role in the regulation of excitatory neurotransmission by combining synaptic recordings from mice deficient for zinc signaling with Monte Carlo simulations. Ambient extracellular zinc levels are too low for tonic occupation of the GluN2A-specific nanomolar zinc sites on NMDA receptors (NMDARs).

T-type channel blockade impairs long-term potentiation at the parallel fiber-Purkinje cell synapse and cerebellar learning.

CaV3.1 T-type channels are abundant at the cerebellar synapse between parallel fibers and Purkinje cells where they contribute to synaptic depolarization. So far, no specific physiological function has been attributed to these channels neither as charge carriers nor more specifically as Ca(2+) carriers.

Single myelin fiber imaging in living rodents without labeling by deep optical coherence microscopy.

Myelin sheath disruption is responsible for multiple neuropathies in the central and peripheral nervous system. Myelin imaging has thus become an important diagnosis tool. However, in vivo imaging has been limited to either low-resolution techniques unable to resolve individual fibers or to low-penetration imaging of single fibers, which cannot provide quantitative information about large volumes of tissue, as required for diagnostic purposes.

A customized pigmentation SNP array identifies a novel SNP associated with melanoma predisposition in the SLC45A2 gene.

As the incidence of Malignant Melanoma (MM) reflects an interaction between skin colour and UV exposure, variations in genes implicated in pigmentation and tanning response to UV may be associated with susceptibility to MM. In this study, 363 SNPs in 65 gene regions belonging to the pigmentation pathway have been successfully genotyped using a SNP array. Five hundred and ninety MM cases and 507 controls were analyzed in a discovery phase I.

Presynaptic NR2A-containing NMDA receptors implement a high-pass filter synaptic plasticity rule.

The detailed characterization of synaptic plasticity has led to the replacement of simple Hebbian rules by more complex rules depending on the order of presynaptic and postsynaptic action potentials. Here, we describe a mechanism endowing a plasticity rule with additional computational complexity--a dependence on the pattern of presynaptic action potentials. The classical Hebbian rule is based on detection of conjunctive presynaptic and postsynaptic activity by postsynaptic NMDA receptors, but there is also accumulating evidence for the existence of presynaptic NMDA receptors in several brain structures.

[Cutaneous myiasis over tumor-lesions: presentation of three cases].

We report three cases of myiasis in patients with tumor-lesions. The first patient, a 54-year-old male, presented with laryngeal carcinoma with extensive local involvement, forming a large tumorous mass on the front of the neck that had been irradiated, where several active larvae were seen. The other two patients, females aged 101 and 87 years, respectively, presented with skin tumors on the scalp and face, and several active larvae could be seen in these tumors.

[Herpetiform pemphigus associated with esophageal carcinoma].

We present the case of a 63-year-old woman with herpetiform pemphigus and disseminated esophageal carcinoma which began to manifest themselves simultaneously. Some cases of herpetiform pemphigus associated with neoplasms have previously been reported, but these have primarily been bronchopulmonary. The association of any type of pemphigus with esophageal cancer is very infrequent.

[Topical treatment of melanoma skin metastases with imiquimod].

The treatment of skin metastases of melanoma can be difficult in many cases because of the patients age, as well as the number, size and location of the lesions. We present the case of an 82-year-old male with melanoma skin metastases on the scalp, which responded satisfactorily to treatment with 5 % imiquimod cream. Imiquimod is a topical immunomodulator with antiviral and antineoplastic action.

Insight, psychopathology, and interpersonal relationships in schizophrenia.

Insight of patients with schizophrenia seems to be a complex phenomenon that includes elements of a psychological, psychopathological, neurocognitive, and interactional nature. The purpose of this research was to study two of these areas (psychopathology and interpersonal relationships) in order to determine their influence on insight and their interrelation. Eighty-two outpatients fulfilling DSM-IV criteria for schizophrenia were studied using the Schedule for the Assessment of Insight (SAI), the Positive and Negative Syndrome Scale (PANSS), and the Social Cognitions and Object Relations Scale (SCORS).

Involvement of presynaptic N-methyl-D-aspartate receptors in cerebellar long-term depression.

At the cerebellar synapses between parallel fibers (PFs) and Purkinje cells (PCs), long-term depression (LTD) of the excitatory synaptic current has been assumed to be independent of the N-methyl-D-aspartate (NMDA) receptor activation because PCs lack NMDA receptors. However, we now report that LTD is suppressed by NMDA receptor antagonists that act on presynaptic NMDA receptors of the PFs. This effect is still observed when the input is restricted to a single fiber.