MEG-SIM: a web portal for testing MEG analysis methods using realistic simulated and empirical data

MEG and EEG measure electrophysiological activity in the brain with exquisite temporal resolution. Because of this unique strength relative to noninvasive hemodynamic-based measures (fMRI, PET), the complementary nature of hemodynamic and electrophysiological techniques is becoming more widely recognized (e.g., Human Connectome Project). However, the available analysis methods for solving the inverse problem for MEG and EEG have not been compared and standardized to the extent that they have for fMRI/PET. A number of factors, including the non-uniqueness of the solution to the inverse problem for MEG/EEG, have led to multiple analysis techniques which have not been tested on consistent datasets, making direct comparisons of techniques challenging (or impossible). Since each of the methods is known to have their own set of strengths and weaknesses, it would be beneficial to quantify them. Toward this end, we are announcing the establishment of a website containing an extensive series of realistic simulated data for testing purposes ( http://cobre.mrn.org/megsim/ ). Here, we present: 1) a brief overview of the basic types of inverse procedures; 2) the rationale and description of the testbed created; and 3) cases emphasizing functional connectivity (e.g., oscillatory activity) suitable for a wide assortment of analyses including independent component analysis (ICA), Granger Causality/Directed transfer function, and single-trial analysis.

Transmission of B virus infection between monkeys especially in relation to breeding colonies

Studies of B virus (Herpesvirus simiae) antibody in several species of macaque lead to the following generalizations. Newborn monkeys are not infected with B virus, even when born of seropositive mothers. Young monkeys remain uninfected until they become adults. The majority of adults develop B virus antibody unless their physical contact with seropositive adults is restricted. These observations are consistent with sexual transmission of B virus and classification of the disease in monkeys as venereal. However, infection at oral and dermal sites also occurs and may play a part in monkey-to-monkey transmission. Epizootics of B virus occurred during early attempts to start B virus-free breeding colonies. They appeared to originate from reactivated latent B virus in adult monkeys which had only low titres of antibody. The stress produced when groups of adult strangers were assembled to form breeding colonies was the most effective known inducer of latent B virus. Total exclusion of animals with any trace of antibody has enabled the establishment of new breeding colonies which are free from B virus.

Yersiniosis in a breeding unit of Macaca fascicularis (cynomolgus monkeys)

2 outbreaks of acute fatal enteric disease involving 20 animals in a breeding unit of approximately 200 cynomolgus monkeys were diagnosed as yersiniosis; Yersinia pseudotuberculosis was isolated from 50% of the clinically affected animals. Post-mortem findings included enlarged mesenteric lymph nodes with some enterocolitis and necrotic foci in liver and spleen. Approximately 7% of clinically healthy monkeys were found to be excreting Y. pseudotuberculosis and a further 5% Y. enterocolitica. Rectal swabs, though less convenient, were better than faecal samples for the detection of Yersinia spp. in 'healthy' monkeys. Efficiency of the cold saline technique and direct plating for isolating Yersinia spp. were compared. It is thought likely that the infection was introduced into the unit by asymptomatic infected monkeys.

The effect of measles vaccination in rhesus monkeys (Macaca mulatta)

30 rhesus monkeys (Macaca mulatta), born into a breeding colony, received measles vaccination when aged between 3 and 26 months; 28 of them were re-vaccinated 5 to 7 months later. Measles virus antibody was measured by haemagglutination-inhibition at the time of each vaccination and again 3 to 6 weeks later. Only 2 out of 9 animals aged less than 6 months responded to vaccination, whereas 10 out of 14 older animals showed 4-fold or greater rises. Re-vaccination of the younger group when aged 8 to 10 months resulted in a marked rise in antibody.

Measles in monkeys: an epidemiological study

This study describes aspects of measles in non-human primates. Monkeys infected before importation are shown to produce non-immune offspring in captivity in England. The high antibody titres found in most recently imported monkeys decline slowly during captivity in England. While measles is often fatal to monkeys, we have described an outbreak in which a number of symptomless infections occurred. Histological examination of fatal cases produced evidence of infection in the wall of the urinary bladder in one monkey. The close similarity between measles in humans and monkeys has been confirmed. It is considered that the study of infection among the latter may have significance for the former.

Control of oxyurids in mice using thiabendazole

Mice with a natural infection of Syphacia obvelata and Aspiculuris tetraptera were continuously medicated with 0.1% thiabendazole in the diet. No oxyurids were found in test animals after 24 days of treatment though control animals remained infected. Growth rates in treated animals increased. 2 generations of mice were studied and, although overall production fell by 1.45%, the use of this drug in total eradication of the worms is suggested.

Establishment of small breeding colony of rhesus monkeys

A breeding colony of 22 female and 4 male rhesus monkeys (Macaca mulatta) was established in a controlled-environment building with an outdoor run. The animals were quarantined for 2 years prior to their release into the unit. The housing, release and management of the colony are described. During the first year 19 young were born of which 17 have survived to 6 months of age. The cost of production and maintenance of the colony when compared with the cost of importing rhesus monkeys would appear to be acceptable.