Cooperative Glutamatergic and Cholinergic Mechanisms Generate Short-Term Modifications of Synaptic Effectiveness in Prepositus Hypoglossi Neurons

To maintain horizontal eye position on a visual target after a saccade, extraocular motoneurons need a persistent (tonic) neural activity, called "eye-position signal," generated by prepositus hypoglossi (PH) neurons. We have shown previously in vitro and in vivo that this neural activity depends, among others mechanisms, on the interplay of glutamatergic transmission and cholinergic synaptically triggered depolarization. Here, we used rat sagittal brainstem slices, including PH nucleus and paramedian pontine reticular formation (PPRF). We made intracellular recordings of PH neurons and studied their synaptic activation from PPRF neurons. Train stimulation of the PPRF area evoked a cholinergic-sustained depolarization of PH neurons that outlasted the stimulus. EPSPs evoked in PH neurons by single pulses applied to the PPRF presented a short-term potentiation (STP) after train stimulation. APV (an NMDA-receptor blocker) or chelerythrine (a protein kinase-C inhibitor) had no effect on the sustained depolarization, but they did block the evoked STP, whereas pirenzepine (an M1 muscarinic antagonist) blocked both the sustained depolarization and the STP of PH neurons. Thus, electrical stimulation of the PPRF area activates both glutamatergic and cholinergic axons terminating in the PH nucleus, the latter producing a sustained depolarization probably involved in the genesis of the persistent neural activity required for eye fixation. M1-receptor activation seems to evoke a STP of PH neurons via NMDA receptors. Such STP could be needed for the stabilization of the neural network involved in the generation of position signals necessary for eye fixation after a saccade

Looking for Competent School Leaders for Indigenous Schools: The New System to Appoint School Leaders in Mexico

The understanding that leadership matters is well regarded in many types of organizations not only in education. In 2015 Mexico implemented a new system to appoint school leaders updating the previous, which was applied for more than four decades. This system aims to appoint the most competent candidate as school principal based on the scores they get on two tests. This study explored how the new system enhances or hinders preparation and readiness for leadership positions, and the effectiveness of tutoring and in-service professional development. Five newly appointed school leaders to Indigenous schools were followed throughout their first year of service. They were interviewed at the beginning, after six months, and at then end of their first year. Thematic analysis was used to process the data gathered from semi-structured interviews using a selective coding approach. Two main predefined themes were explored in this study: Leadership Preparation and Tutoring and Professional Development. Findings indicate that for schools located in remote Indigenous communities, isolation and the lack of communication infrastructure, such as internet and phone signal, hinder the possibility of effective training and tutoring.This study concludes that even though the new system seems to have made progress in appointing better school leaders, it is only partial since aspiring leaders are neither required to make specific preparation for their new post nor offered these opportunities, hindering their readiness to enact headship effectively

The Appointment of School Heads in Mexican Primary Schools: An Exploratory Study of the System of Promotion.

This work explored the Mexican system to appoint school leaders from a perspective that could consider its positive aspects and as well as its shortcomings. This research was framed as an exploratory case study. Three types of participants were interviewed: five aspiring heads, twelve incumbent heads, and four administrators of the promotion system. Thematic analysis was the procedure adopted in the analysis of transcripts. The research was carried out to the highest ethical standards in educational research as it was granted ethical approval by Birmingham University, and BERA’s Ethical Guidelines for Educational Research (2011) were adhered to throughout the study. The study revealed that there are some positive aspects in the Mexican system that could enable its consolidation. The study found also a need to upgrade the current system of promotion since school leaders in Mexico are appointed by a system in which its regulations and procedures were promulgated more than 40 years ago. The current system of promotion does not enable the appointment of prepared school leaders. The findings revealed a need for leadership preparation as a prerequisite for participants in competitions for deputy headships, headships and, also for those who are already holding a leadership position

Las cifras de la documentación en España: 2002

The state of the Spanish LIS profession and specialities in 2002 is reviewed. Statistical data is provided about both the number and type of Spanish libraries and archives as well as of practising professionals, according to geographic distribution, training and job description. Spanish library and information authorities are identified as well as professional associations and learned societies and conferences held. University education is also examined with descriptions of existing institutions, degree levels and data on student enrolment and teachers. The primary media for professional communication are described, in particular, publishers, bulletins, scientific journals and electronic fora. Publishing output is quantified: books, journal articles, and conference papers both at national and international levels. Finally, research in the field is analysed through the total of Ph. D. dissertations presented, research articles published and research projects funded

Las revistas científicas españolas de ciencias de la salud en 1993.

An analysis about spanish scientific journals in health sciences in 1993 is presented

La enseñanza de metodología de la investigación en las Escuelas de Biblioteconomía y Documentación de USA Gran Bretaña y Canada

The teaching of research metodology in USA, Great Britain and Canada is studied

Role of Cerebellar Interpositus Nucleus in the Genesis and Control of Reflex and Conditioned Eyelid Responses

The role of cerebellar circuits in the acquisition of new motor abilities is still a matter of intensive debate. To establish the contribution of posterior interpositus nucleus (PIN) to the performance and/or acquisition of reflex and classically conditioned responses (CRs) of the eyelid, the effects of microstimulation and/or pharmacological inhibition by muscimol of the nucleus were investigated in conscious cats. Microstimulation of the PIN in naive animals evoked ramp-like eyelid responses with a wavy appearance, without producing any noticeable plastic functional change in the cerebellar and brainstem circuits involved. Muscimol microinjections decreased the amplitude of reflex eyeblinks evoked by air puffs, both when presented alone or when paired with a tone as conditioned stimulus (CS). In half-conditioned animals, muscimol injections also decreased the amplitude and damped the typical wavy profile of CRs, whereas microstimulation of the same sites increased both parameters. However, neither muscimol injections nor microstimulation modified the expected percentage of CRs, suggesting a major role of the PIN in the performance of eyelid responses rather than in the learning process. Moreover, the simultaneous presentation of CS and microstimulation in well trained animals evoked CRs similar in amplitude to the added value of those evoked by the two stimuli presented separately. In contrast, muscimol-injected animals developed CRs to paired CS and microstimulation presentations, larger than those evoked by the two stimuli when presented alone. It is concluded that the PIN contributes to the enhancement of both reflex and conditioned eyelid responses and to the damping of resonant properties of neuromuscular elements controlling eyelid kinematics