Solving the mystery of memory

The word "memory" is derived from the ancient Greek myth of Mnemosyne, the mother of the Muses, who was "said to know everything, past, present, and future." Memory is essential to our existence, and one of neuroscience's primary missions is to understand how the brain processes memory and to improve treatments for Alzheimer's disease, traumatic brain injury, drug addiction, and the many other afflictions associated with disrupted memory. Our article traces scientists' progress in understanding memory over the last 15 years.

Obligatory role for the immediate early gene NARP in critical period plasticity

The immediate early gene neuronal activity-regulated pentraxin (NARP) is an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) binding protein that is specifically enriched at excitatory synapses onto fast-spiking parvalbumin-positive interneurons (FS [PV] INs). Here, we show that transgenic deletion of NARP decreases the number of excitatory synaptic inputs onto FS (PV) INs and reduces net excitatory synaptic drive onto FS (PV) INs. Accordingly, the visual cortex of NARP(-/-) mice is hyperexcitable and unable to express ocular dominance plasticity, although many aspects of visual function are unimpaired. Importantly, the number and strength of inhibitory synaptic contacts from FS (PV) INs onto principle neurons in the visual cortex is normal in NARP(-/-) mice, and enhancement of this output recovers the expression of experience-dependent synaptic plasticity. Thus the recruitment of inhibition from FS (PV) INs plays a central role in enabling the critical period for ocular dominance plasticity.

Loss of vascular early response gene reduces edema formation after experimental stroke

Vascular Early Response Gene (Verge) is an immediate early gene (IEG) that is up-regulated in endothelial cells in response to a number of stressors, including ischemic stroke. Endothelial cell lines that stably express Verge show enhanced permeability. Increased Verge expression has also been associated with blood brain barrier breakdown. In this study we investigated the role of Verge in ischemic injury induced by middle cerebral artery occlusion (MCAO) in both Verge knockout (KO) and wild type (WT) mice. Verge KO mice had significantly less cerebral edema formation after MCAO compared to WT mice. However, stroke outcome (infarct size and neurological deficit scores) evaluated at either 24 or 72 hours after stroke showed no differences between the two genotypes. Verge deletion leads to decreased edema formation after ischemia; however acute stroke outcomes were unchanged.

Role of Homer proteins in the maintenance of sleep-wake states

Sleep is an evolutionarily conserved process that is linked to diurnal cycles and normal daytime wakefulness. Healthy sleep and wakefulness are integral to a healthy lifestyle; this occurs when an organism is able to maintain long bouts of both sleep and wake. Homer proteins, which function as adaptors for group 1 metabotropic glutamate receptors, have been implicated in genetic studies of sleep in both Drosophila and mouse. Drosophila express a single Homer gene product that is upregulated during sleep. By contrast, vertebrates express Homer as both constitutive and immediate early gene (H1a) forms, and H1a is up-regulated during wakefulness. Genetic deletion of Homer in Drosophila results in fragmented sleep and in failure to sustain long bouts of sleep, even under increased sleep drive. However, deletion of Homer1a in mouse results in failure to sustain long bouts of wakefulness. Further evidence for the role of Homer1a in the maintenance of wake comes from the CREB alpha delta mutant mouse, which displays a reduced wake phenotype similar to the Homer1a knockout and fails to up-regulate Homer1a upon sleep loss. Homer1a is a gene whose expression is induced by CREB. Sustained behaviors of the sleep/wake cycle are created by molecular pathways that are distinct from those for arousal or short bouts, and implicate an evolutionarily-conserved role for Homer in sustaining these behaviors.

Can medical education in poor rural areas be cost-effective and sustainable: the case of the Ateneo de Zamboanga University School of Medicine

INTRODUCTION

This study examined the hypothesis that a medical school in a low-resource setting, based on volunteer faculty, can be sustainable and associated with improvement in medical workforce and population health outcomes.

METHODS

Using a retrospective case study approach, this study described the formation of the Ateneo de Zamboanga University School of Medicine (ADZU SOM) in Zamboanga province, Mindanao, Philippines. The principal outcome measures were the number of graduated students practicing as physicians in the Philippines, the number of local municipalities with doctors, and changes in the provincial infant mortality rate since the School's inception.

RESULTS

Since the first 15 graduates in 1999, by 2011 more than 160 students had successfully graduated with over 80% practicing in the local underserved regions. This compares with a national average of 68% of Philippine medical graduates practicing overseas. There has been a 55% increase (n=20 to 31) in the number of municipalities in Zamboanga with a doctor. Since the ADZU SOM's inception in 1994, the infant mortality rate in the region has decreased by approximately 90%, compared with a national change of approximately 50% in the same time period. The School has only three employees because all teachers continue to work as volunteer clinicians from the local health services.

CONCLUSIONS

These results can encourage governments and communities around the world to consider adopting a socially accountable approach to medical education as a cost-effective strategy to improve medical workforce in underserved areas.

Demonstrating the value of longitudinal integrated placements to general practice preceptors

CONTEXT

This paper aims to consider why general practitioners (GPs) teach, in particular by defining the longitudinal supervisory relationships between rural clinician-preceptors and students.

METHODS

A total of 41 individual semi-structured interviews were conducted with GPs, practice managers and students. All interviews were audiotaped, transcribed and analysed for emergent themes.

RESULTS

In this study preceptors identified many ways in which precepting added value to their roles. However, themes relating to the doctor-student relationship were central to GP preceptors' experiences. These developed in chronological order and resulted in changes in the triangular relationship between doctor, patient and student in the consultation.

DISCUSSION

Interpretive findings identify that the motivators for precepting represent a group of constantly changing interconnected factors that contribute to the defining of preceptors as central members of their professional community of practice. This critical finding challenges the simplistic organisational concept that universities can recruit and retain GPs by offering increased rewards. This paper introduces four clinical preceptor models, which involve the roles of, respectively: the student-observer; the teacher-healer; the doctor-orchestrator, and the doctor-advisor. Symbiosis between student learning and patient care was found to occur in the doctor-orchestrator model.

CONCLUSIONS

The evolution of doctor-student relationships in long-term student placements explains how students become more useful over the academic year and sheds light on how GPs are changed through precepting as part of the complex process by which they come to recognise themselves as central members of the rural generalist community.

Social accountability in medical education--an Australian rural and remote perspective

Australia's medical education system is undergoing a socially motivated transformation focused on improving access to medical care for rural and remote communities. A rural and remote backbone of Rural Clinical Schools (RCS), University Departments of Rural Health, regional medical schools, and the postgraduate college, ACRRM, have enabled community responsive innovation and partnerships with rural health services that once would have been difficult to imagine. This article argues that this transformation is succeeding because of the passionate leadership of rural medical and community leaders, government seed funding to encourage rural medicine as an academic discipline, rigorous research and consultation that underpinned each step of the innovation pathway, and a political campaign to invest in rural medical education as a form of rural social capital.

Development of the Rural Immersion Programme for 5th-year medical students at the University Of Otago

AIMS

To report the development of the first Rural Medical Immersion Programme (RMIP) of the University of Otago in New Zealand.

METHOD

We review medical education trends and challenges for educating New Zealand's doctors and recruiting them to careers in rural practice. We describe key features of the RMIP developed in response to these challenges.

RESULTS

Medical education is evolving from discipline and hospital-based teaching to using more integrated, community-based teaching. The RMIP aims to immerse 5th-year medical students in an integrated, patient-centred, community-based, parallel learning environment where learners' experiences in primary, secondary, and tertiary settings are always based on patient care. Government funding for the RMIP pilot was granted in November 2006 and the first 6 students started in the programme in 2007. Experiences of the programme from 2007-2009 are reported.

CONCLUSION

The RMIP remains true to the principles underpinning its establishment and has to date delivered successful medical education outcomes for the first 18 students of the 2007 and 2008 cohorts. We cannot yet assess its role in future recruitment to rural medical careers.

TORC1 and TORC2 selectively regulate CD4+ T helper cell lineage differentiation (50.35)

The mammalian target of rapamycin (mTOR) is a highly conserved serine-threonine kinase that regulates cell division, survival, and translation. Downstream mTOR signals via two functionally distinct complexes, TORC1 and TORC2. We have previously shown T cells deficient in mTOR fail to differentiate into Th1, Th2, or Th17 cells and instead become Foxp3+ regulatory cells. We further dissected mTOR signaling in T cell differentiation by deleting Rheb (the activator of TORC1) and rictor (an essential TORC2 subunit). T cells lacking Rheb selectively lack TORC1 activity, and, like mTOR mutants, fail to differentiate into Th1 or Th17 cells when skewed. However, Rheb-deficient T cells retain their ability to become Th2 cells. This is due in part to diminished STAT4 and STAT3 activation, but elevated STAT6 activation. Alternatively, rictor-deficient cells specifically lack TORC2 activity, and fail to become Th2 cells when skewed. However, they retain the ability to become Th1 and Th17 cells, with a pattern of STAT activation that inversely correlates with TORC1 mutants. Interestingly, neither TORC1 nor TORC2 deficiency alone is sufficient to induce Treg differentiation. In vivo, TORC1 deficiency protects against EAE while TORC2 deficiency leads to accelerated disease. Our data support a novel paradigm in which TCR engagement in the absence of mTOR defaults to a regulatory fate, and TORC1 and TORC2 activation selectively regulate T cell effector lineage differentiation.

Homer1a-dependent crosstalk between NMDA and metabotropic glutamate receptors in mouse neurons

Background

A large number of evidences suggest that group-I metabotropic glutamate receptors (mGluR1a, 1b, 1c, 5a, 5b) can modulate NMDA receptor activity. Interestingly, a physical link exists between these receptors through a Homer-Shank multi-protein scaffold that can be disrupted by the immediate early gene, Homer1a. Whether such a versatile link supports functional crosstalk between the receptors is unknown.

Methodology/Principal Findings

Here we used biochemical, electrophysiological and molecular biological approaches in cultured mouse cerebellar neurons to investigate this issue. We found that Homer1a or dominant negative Shank3 mutants that disrupt the physical link between the receptors allow inhibition of NMDA current by group-I mGluR agonist. This effect is antagonized by pertussis toxin, but not thapsigargin, suggesting the involvement of a G protein, but not intracellular calcium stores. Also, this effect is voltage-sensitive, being present at negative, but not positive membrane potentials. In the presence of DHPG, an apparent NMDA “tail current” was evoked by large pulse depolarization, only in neurons transfected with Homer1a. Co-immunoprecipitation experiments showed interaction between G-protein βγ subunits and NMDA receptor in the presence of Homer1a and group-I mGluR agonist.

Conclusions/Significance

Altogether these results suggest a direct inhibition of NMDA receptor-channel by Gbetagamma subunits, following disruption of the Homer-Shank3 complex by the immediate early gene Homer1a. This study provides a new molecular mechanism by which group-I mGluRs could dynamically regulate NMDA receptor function.

Using rural and remote settings in the undergraduate medical curriculum: AMEE Guide No. 47

The goal of global equity in health care requires that the training of health-care professionals be better tuned to meet the needs of the communities they serve. In fact medical education is being driven into isolated communities by factors including workforce undersupply, education pedagogy, medical practice and research needs. Rural and remote medical education (RRME) happens in rural hospitals and rural general practices, singly or in combination, generally for periods of 4 to 40 weeks. An effective RRME programme matches the context of the local health service and community. Its implementation reflects the local capacity for providing learning opportunities, facilitates collaboration of all participants and capitalises on local creativity in teaching. Implementation barriers stem from change management, professional culture and resource allocation. Blending learning approaches as much as technology and local culture allow is central to achieving student learning outcomes and professional development of local medical teachers. RRME harnesses the rich learning environment of communities such that students rapidly achieve competence and confidence in a primary care/generalist setting. Longer programmes with an integrated (generalist) approach based in the immersion learning paradigm appear successful in returning graduates to rural practice and a career track with a quality lifestyle.

Effectiveness of point-of-care testing for therapeutic control of chronic conditions: results from the PoCT in General Practice Trial

OBJECTIVE

To compare the clinical effectiveness of point-of-care testing (PoCT) and that of pathology laboratory testing, as measured by therapeutic control in chronic conditions.

DESIGN

Multicentre, cluster randomised controlled trial using non-inferiority analysis.

SETTING

53 Australian general practices in urban, rural and remote areas across three Australian states, September 2005 to February 2007.

PARTICIPANTS

4968 patients with established type 1 or type 2 diabetes, established hyperlipidaemia, or taking anticoagulant therapy.

INTERVENTION

The intervention group (3010 patients in 30 practices) had blood and urine samples tested by PoCT devices in their general practices, and the control group (1958 patients in 23 practices) had samples tested by their usual pathology laboratories.

MAIN OUTCOME MEASURES

The proportion of patients and of tests with results in the target range, and change in test results from baseline.

RESULTS

For the proportion of patients with results in the target range, PoCT was found to be non-inferior to pathology laboratory testing for measuring glycated haemoglobin (HbA(1c)), urine albumin, albumin-creatinine ratio (ACR), total cholesterol and triglyceride levels but not for high-density lipoprotein (HDL) cholesterol level and international normalised ratio (INR). For the proportion of tests with results in the target range, PoCT was found to be non-inferior to pathology laboratory testing for measuring all variables except HDL cholesterol. For the proportion of patients showing an improvement in their test result from baseline, PoCT was non-inferior to pathology laboratory testing for HbA(1c), total cholesterol and triglyceride levels, but not for HDL cholesterol level.

CONCLUSIONS

This study provides important evidence for those considering the introduction of PoCT into general practice. For all tests except INR and HDL cholesterol, the PoCT approach demonstrated the same or better clinical effectiveness than pathology laboratory testing.

TRIAL REGISTRATION

Australian Clinical Trials Registry ACTRN12612607000628448.

Design, implementation and results of the quality control program for the Australian government's point of care testing in general practice trial

BACKGROUND

From 2005 to 2007 the Australian Government funded a multicentre, clustered randomized controlled trial to determine the clinical effectiveness, cost-effectiveness, satisfaction and safety of point of care testing (PoCT) in general practice (GP). PoC tests measured (and devices used) in the trial were haemoglobin A1c and urine albumin:creatinine ratio (DCA 2000), lipids (Cholestech LDX) and international normalized ratio (CoaguChek S).

METHODS

An internal quality control (QC) program was developed as part of a quality management framework for the trial. PoCT device operators were provided with a colour-coded QC Result Sheet and QC Action Sheet for on-site recording and interpreting of their results. Within-practice imprecision for QC testing was calculated and compared with the analytical goals for imprecision set prior to the trial.

RESULTS

The average participation rate for QC testing was 91% or greater. Median within-practice imprecision met the analytical goals for all PoC tests, except for high-density lipoprotein-cholesterol (HDL-C) where observed performance was outside the minimum goal for one level and one lot number of QC. Most practices achieved the imprecision goals for all analytes, with the principal exception of HDL-C.

CONCLUSIONS

Results from QC testing indicate that PoCT in the GP trial met the analytical goals set for the trial, with the exception of HDL-C.

What do general practitioners do differently when consulting with a medical student?

OBJECTIVES

The practice of having medical students see patients in a general practice setting, in their own consulting rooms, prior to the GP preceptor joining the consultation does not increase general practitioner (GP) consultation time. How do GPs meet the needs of both patient and student without extending consultation time? This study sought to quantify and compare GP consultation activities with and without students.

METHODS

This was a prospective cohort study of 523 videotaped consultations. Consultations were analysed in 15-second intervals using a modified Davis observation code to define GP activity. Estimated marginal means were calculated using mixed model analysis accounting for confounding factors.

RESULTS

In comparison with consulting alone, GPs precepting a student spent 37 seconds less time examining patients (P = 0.001), 41 seconds less on patient management, and 1 minute, 31 seconds less on clerical and other activities (P < 0.001). This created time for GPs to take a history from both the student and patient (39 seconds longer; P = 0.002) and to teach students (1 minute, 10 seconds; P < 0.001).

DISCUSSION

General practitioner activity in the consultation changes significantly when precepting a student; GPs spend longer exploring the history in order to unpack the student's clinical reasoning, verify the patient's story and resynthesise the information. They spend less time on examination, management and clerical activities and presumably delegate or defer these activities. Conclusions This organising of clinical activities in order to meet the needs of both patient and student is likely to require different processing skills to solo consulting.