Aggression in Group-Housed Male Mice: A Systematic Review

Aggression among group-housed male mice is a major animal welfare concern often observed at animal facilities. Studies designed to understand the causes of male mice aggression have used different methodological approaches and have been heterogeneous, using different strains, environmental enrichments, housing conditions, group formations and durations. By conducting a systematic literature review based on 198 observed conclusions from 90 articles, we showed that the methodological approach used to study aggression was relevant for the outcome and suggested that home cage observations were better when studying home cage aggression than tests provoking aggression outside the home cage. The study further revealed that aggression is a complex problem; one solution will not be appropriate for all animal facilities and all research projects. Recommendations were provided on promising tools to minimize aggression, based on the results, which included what type of environmental enrichments could be appropriate and which strains of male mice were less likely to be aggressive.

Interactions between poloxamer, PEOx-PPOy-PEOx, and non-ionic surfactant, sucrose monolaurate: A study on potential allergenic effect using model phospholipid membrane

Sugar-based surfactants are involved in skin related allergy cases in the past decade. Skin irritation starts with the interaction of the surfactant with the skin lipids leading to lipid emulsification and eventual barrier damage. Polymers or co-surfactants can be used to mitigate the allergenic effect but the mechanism of formulation mildness on skin remains unclear. We have used the quartz crystal microbalance (QCM) together with dissipative particle dynamics (DPD) simulation, small angle x-ray scattering (SAXS) as well as cell viability tests to decipher the interactions between poloxamers and sucrose monolaurate (SML), and how these interactions could prevent the disruption of a model supported phospholipid bilayer (SLB). Poloxamer addition to the SML solution can delay or totally prevent the disruption of the SLB depending on poloxamer type and concentration. Poloxamer P407 (Pluronic® F127) delays the onset of disruption while poloxamer P188 (Pluronic® F68) does not preserve the bilayer integrity even at high concentration of up to 15% w/w. Preservation of the SLB is likely due to the differences in the aggregates formation between SML-F127 and SML-F68 mixtures with corresponding retarded motion of SML micelles through the SML-F127 polymer matrix that improved cell viability.

Optimism, pessimism and judgement bias in animals: A systematic review and meta-analysis

Just as happy people see the proverbial glass as half-full, 'optimistic' or 'pessimistic' responses to ambiguity might also reflect affective states in animals. Judgement bias tests, designed to measure these responses, are an increasingly popular way of assessing animal affect and there is now a substantial, but heterogeneous, literature on their use across different species, affect manipulations, and study designs. By conducting a systematic review and meta-analysis of 459 effect sizes from 71 studies of non-pharmacological affect manipulations on 22 non-human species, we show that animals in relatively better conditions, assumed to generate more positive affect, show more 'optimistic' judgements of ambiguity than those in relatively worse conditions. Overall effects are small when considering responses to all cues, but become more pronounced when non-ambiguous training cues are excluded from analyses or when focusing only on the most divergent responses between treatment groups. Task type (go/no-go; go/go active choice), training cue reinforcement (reward-punishment; reward-null; reward-reward) and sex of animals emerge as potential moderators of effect sizes in judgement bias tests.

Pharmacological manipulations of judgement bias: A systematic review and meta-analysis

Validated measures of animal affect are crucial to research spanning numerous disciplines. Judgement bias, which assesses decision-making under ambiguity, is a promising measure of animal affect. One way of validating this measure is to administer drugs with affect-altering properties in humans to non-human animals and determine whether the predicted judgement biases are observed. We conducted a systematic review and meta-analysis using data from 20 published research articles that use this approach, from which 557 effect sizes were extracted. Pharmacological manipulations overall altered judgement bias at the probe cues as predicted. However, there were several moderating factors including the neurobiological target of the drug, whether the drug induced a relatively positive or negative affective state in humans, dosage, and the presented cue. This may partially reflect interference from adverse effects of the drug which should be considered when interpreting results. Thus, the overall pattern of change in animal judgement bias appears to reflect the affect-altering properties of drugs in humans, and hence may be a valuable measure of animal affective valence.

Generalization of learned preferences covaries with behavioral flexibility in red junglefowl chicks

The relationship between animal cognition and consistent among-individual behavioral differences (i.e., behavioral types, animal personality, or coping styles), has recently received increased research attention. Focus has mainly been on linking different behavioral types to performance in learning tasks. It has been suggested that behavioral differences could influence also how individuals use previously learnt information to generalize about new stimuli with similar properties. Nonetheless, this has rarely been empirically tested. Here, we therefore explore the possibility that individual variation in generalization is related to variation in behavioral types in red junglefowl chicks (Gallus gallus). We show that more behaviorally flexible chicks have a stronger preference for a novel stimulus that is intermediate between 2 learnt positive stimuli compared to more inflexible chicks. Thus, more flexible and inflexible chicks differ in how they generalize. Further, behavioral flexibility correlates with fearfulness, suggesting a coping style, supporting that variation in generalization is related to variation in behavioral types. How individuals generalize affects decision making and responses to novel situations or objects, and can thus have a broad influence on the life of an individual. Our results add to the growing body of evidence linking cognition to consistent behavioral differences.

Heritabilities and co-variation among cognitive traits in red junglefowl

Natural selection can act on between-individual variation in cognitive abilities, yet evolutionary responses depend on the presence of underlying genetic variation. It is, therefore, crucial to determine the relative extent of genetic versus environmental control of these among-individual differences in cognitive traits to understand their causes and evolutionary potential. We investigated heritability of associative learning performance and of a cognitive judgement bias (optimism), as well as their covariation, in a captive pedigree-bred population of red junglefowl (Gallus gallus, n > 300 chicks over 5 years). We analysed performance in discriminative and reversal learning (two facets of associative learning), and cognitive judgement bias, by conducting animal models to disentangle genetic from environmental contributions. We demonstrate moderate heritability for reversal learning, and weak to no heritability for optimism and discriminative learning, respectively. The two facets of associative learning were weakly negatively correlated, consistent with hypothesized trade-offs underpinning individual cognitive styles. Reversal, but not discriminative learning performance, was associated with judgement bias; less optimistic individuals reversed a previously learnt association faster. Together these results indicate that genetic and environmental contributions differ among traits. While modular models of cognitive abilities predict a lack of common genetic control for different cognitive traits, further investigation is required to fully ascertain the degree of covariation between a broader range of cognitive traits and the extent of any shared genetic control.This article is part of the theme issue 'Causes and consequences of individual differences in cognitive abilities'.

The relationship between learning speed and personality is age- and task-dependent in red junglefowl

Abstract

Cognition is fundamental to animals’ lives and an important source of phenotypic variation. Nevertheless, research on individual variation in animal cognition is still limited. Further, although individual cognitive abilities have been suggested to be linked to personality (i.e., consistent behavioral differences among individuals), few studies have linked performance across multiple cognitive tasks to personality traits. Thus, the interplays between cognition and personality are still unclear. We therefore investigated the relationships between an important aspect of cognition, learning, and personality, by exposing young and adult red junglefowl (Gallus gallus) to multiple learning tasks (discriminative, reversal, and spatial learning) and personality assays (novel arena, novel object, and tonic immobility). Learning speed was not correlated across learning tasks, and learning speed in discrimination and spatial learning tasks did not co-vary with personality. However, learning speed in reversal tasks was associated with individual variation in exploration, and in an age-dependent manner. More explorative chicks learned the reversal task faster than less explorative ones, while the opposite association was found for adult females (learning speed could not be assayed in adult males). In the same reversal tasks, we also observed a sex difference in learning speed of chicks, with females learning faster than males. Our results suggest that the relationship between cognition and personality is complex, as shown by its task- and age-dependence, and encourage further investigation of the causality and dynamics of this relationship.

Significance statement

In the ancestor of today’s chickens, the red junglefowl, we explored how personality and cognition relate by exposing both chicks and adults to several learning tasks and personality assays. Our birds differed in personality and learning speed, while fast learners in one task did not necessarily learn fast in another (i.e., there were no overall “smarter” birds). Exploration correlated with learning speed in the more complex task of reversal learning: faster exploring chicks, but slower exploring adult females, learned faster, compared to less explorative birds. Other aspects of cognition and personality did not correlate. Our results suggest that cognition and personality are related, and that the relationship can differ depending on task and age of the animal.

Electronic supplementary material

The online version of this article (10.1007/s00265-018-2579-2) contains supplementary material, which is available to authorized users.

The Influence of Rearing on Behavior, Brain Monoamines, and Gene Expression in Three-Spined Sticklebacks

The causes of individual variation in behavior are often not well understood, and potential underlying mechanisms include both intrinsic and extrinsic factors, such as early environmental, physiological, and genetic differences. In an exploratory laboratory study, we raised three-spined sticklebacks (Gasterosteus aculeatus) under 4 different environmental conditions (simulated predator environment, complex environment, variable social environment, and control). We investigated how these manipulations related to behavior, brain physiology, and gene expression later in life, with focus on brain dopamine and serotonin levels, turnover rates, and gene expression. The different rearing environments influenced behavior and gene expression, but did not alter monoamine levels or metabolites. Specifically, compared to control fish, fish exposed to a simulated predator environment tended to be less aggressive, more exploratory, and more neophobic; and fish raised in both complex and variable social environments tended to be less neophobic. Exposure to a simulated predator environment tended to lower expression of dopamine receptor DRD4A, a complex environment increased expression of dopamine receptor DRD1B, while a variable social environment tended to increase serotonin receptor 5-HTR2B and serotonin transporter SLC6A4A expression. Despite both behavior and gene expression varying with early environment, there was no evidence that gene expression mediated the relationship between early environment and behavior. Our results confirm that environmental conditions early in life can affect phenotypic variation. However, the mechanistic pathway of the monoaminergic systems translating early environmental variation into observed behavioral responses was not detected.

Comparative support for the expensive tissue hypothesis: Big brains are correlated with smaller gut and greater parental investment in Lake Tanganyika cichlids

The brain is one of the most energetically expensive organs in the vertebrate body. Consequently, the energetic requirements of encephalization are suggested to impose considerable constraints on brain size evolution. Three main hypotheses concerning how energetic constraints might affect brain evolution predict covariation between brain investment and (1) investment into other costly tissues, (2) overall metabolic rate, and (3) reproductive investment. To date, these hypotheses have mainly been tested in homeothermic animals and the existing data are inconclusive. However, there are good reasons to believe that energetic limitations might play a role in large-scale patterns of brain size evolution also in ectothermic vertebrates. Here, we test these hypotheses in a group of ectothermic vertebrates, the Lake Tanganyika cichlid fishes. After controlling for the effect of shared ancestry and confounding ecological variables, we find a negative association between brain size and gut size. Furthermore, we find that the evolution of a larger brain is accompanied by increased reproductive investment into egg size and parental care. Our results indicate that the energetic costs of encephalization may be an important general factor involved in the evolution of brain size also in ectothermic vertebrates.

Abnormal expression of dysferlin in skeletal muscle and monocytes supports primary dysferlinopathy in patients with one mutated allele

BACKGROUND

In some cases, a definitive confirmation of dysferlinopathy cannot be achieved by DNA test, because the mutation is detected in one allele only.

PATIENTS AND METHODS

DYSFERLIN expression in skeletal muscle and peripheral blood monocytes (PBM) was studied by Western blot in two unrelated adult patients. The comparative C(T) method (ΔΔC(T) ) was used to calculate relative changes in dysferlin mRNA determined from real-time quantitative PCR experiments. The dysferlin gene was studied by direct sequencing of cDNA and genomic DNA and by Multiplex Ligation-dependent Probe Amplification (MLPA) analysis.

RESULTS

A comparable severe reduction in dysferlin was demonstrated in both skeletal muscle and PBM. The expression of dysferlin mRNA was significantly reduced. A novel mutation in exon 47 (c.5289G>C) of the dysferlin gene in the heterozygous state, causing an amino acid change (p.Glu1763Asp), was detected in both patients. The MLPA analysis did not reveal any deletion or duplication.

CONCLUSIONS

Dysferlin and/or dysferlin mRNA abnormalities are diagnostic for dysferlinopathy when mutational analysis detects a mutation in one allele only. Analysis of dysferlin mRNA can be helpful for distinguishing symptomatic heterozygotes from such patients.

Functional changes of the cortical motor system in hereditary spastic paraparesis

BACKGROUND

Hereditary spastic paraparesis (HSP) is a heterogeneous group of disorders characterized by progressive bilateral lower limb spasticity. Functional imaging studies in patients with corticospinal tract involvement have shown reorganization of motor circuitry. Our study investigates functional changes in sensorimotor brain areas in patients with HSP.

METHODS

Twelve subjects with HSP and 12 healthy subjects were studied. Functional magnetic resonance imaging (fMRI) was used to measure brain activation during right-hand finger tapping. Image analysis was performed using general linear model and regions of interest (ROI)-based approach. Weighted laterality indices (wLI) and anterior/posterior indicies (wAI and wPI) were calculated for predefined ROIs.

RESULTS AND DISCUSSION

Comparing patients and controls at the same finger-tapping rate (1.8 Hz), there was increased fMRI activation in patients' bilateral posterior parietal cortex and left primary sensorimotor cortex. No differences were found when comparing patients and controls at 80% of their individual maximum tapping rates. wLI of the primary sensorimotor cortex was significantly lower in patients. Subjects with HSP also showed a relative increase in the activation of the posterior parietal and premotor areas compared with that of the primary sensorimotor cortex. Our findings demonstrate an altered pattern of cortical activation in subjects with HSP during motor task. The increased activation probably reflects reorganization of the cortical motor system.

ALS and FTLD: two faces of TDP-43 proteinopathy

Major discoveries have been made in the recent past in the genetics, biochemistry and neuropathology of frontotemporal lobar degeneration (FTLD). TAR DNA-binding protein 43 (TDP-43), encoded by the TARDBP gene, has been identified as the major pathological protein of FTLD with ubiquitin-immunoreactive (ub-ir) inclusions (FTLD-U) with or without amyotrophic lateral sclerosis (ALS) and sporadic ALS. Recently, mutations in the TARDBP gene in familial and sporadic ALS have been reported which demonstrate that abnormal TDP-43 alone is sufficient to cause neurodegeneration. Several familial cases of FTLD-U, however, are now known to have mutations in the progranulin (GRN) gene, but granulin is not a component of the TDP-43- and ub-ir inclusions. Further, TDP-43 is found to be a component of the inclusions of an increasing number of neurodegenerative diseases. Other FTLD-U entities with TDP-43 proteinopathy include: FTLD-U with valosin-containing protein (VCP) gene mutation and FTLD with ALS linked to chromosome 9p. In contrast, chromosome 3-linked dementia, FTLD-U with chromatin modifying protein 2B (CHMP2B) mutation, has ub-ir, TDP-43-negative inclusions. In summary, recent discoveries have generated new insights into the pathogenesis of a spectrum of disorders called TDP-43 proteinopathies including: FTLD-U, FTLD-U with ALS, ALS, and a broadening spectrum of other disorders. It is anticipated that these discoveries and a revised nosology of FTLD will contribute toward an accurate diagnosis, and facilitate the development of new diagnostic tests and therapeutics.

Relation of CTG expansion and clinical variables to electrocardiogram conduction abnormalities and sudden death in patients with myotonic dystrophy

We prospectively followed 63 patients with myotonic dystrophy (DM) after establishing diagnosis of DM for an average 8 years in an attempt to detect conduction disturbances (by electrocardiography and/or Holter monitoring) and sudden cardiac events (sudden death, cardiac syncope) and correlate them to potential predicting factors (CTG repeat expansion in the myotonin protein kinase gene and several clinical variables: clinical type and duration of DM, age and sex). Twenty-six patients developed conduction disturbances, five patients died suddenly, and two patients experienced cardiac syncope necessitating urgent implantation of pacemaker. Analysis showed no significant correlation between conduction disturbances and/or cardiac events and CTG expansion. Furthermore, no correlation was found with type of DM, whereas conduction disturbances and sudden cardiac events correlated with patients' age, duration of disease and male sex. Results on our cohort of DM patients show that CTG expansion has no role in predicting neither conduction abnormalities nor sudden death. It seems that risk of sudden death increases with duration of disease and age, and that risk is higher in male patients.

Actigraphic assessment of sleep-wake rhythm during the first 6 months of life

OBJECTIVES

To examine the validity of the "Gaehwiler" actigraph (Gaehwiler Electronics, model Z80-32k V(1)) for the assessment of sleep-wake (S/W) rhythm and sleep structure in infants during the first 6 months of life using an algorithm developed in our laboratory to differentiate sleep and wake states.

METHODS

A continuous 72 h actigraphic recording was performed in 10 healthy infants at 1, 3 and 6 months of age. The actigraphic data were matched to direct observation of the infants' behavioural states. Using discriminant function analysis a scoring algorithm for automatic identification of S/W states from raw activity data was developed. The chi-square periodogram analysis was performed to estimate periodic components of S/W rhythm.

RESULTS

The overall agreement rates between the actigraphic and observer scoring for S/W were between 87 and 95% for the infants after the third month of life, while for the 1-month-old infants they never exceeded 72%. The actigraphic discrimination between active and quiet sleep was the best in 3-month-old infants. The circadian influence on S/W rhythm was already present by the end of the first month of life.

CONCLUSIONS

Using the "Gaehwiler" actigraph in our study, valid discrimination between sleep and wake states was obtained in infants during 3 and 6 months. The actigraph, however, did not provide valid active vs. quiet sleep state measures. The circadian rhythm of S/W was observed as early as during the first month of life.

Enoxaparin and abciximab adjunctive pharmacotherapy during percutaneous coronary intervention

Randomized controlled trials of patients with non-ST segment elevation acute coronary syndromes have established the superiority of enoxaparin (versus unfractionated heparin) for reducing adverse ischemic outcomes. Furthermore, adjunctive abciximab therapy during percutaneous coronary intervention (PCI) is associated with improved clinical outcomes. Since algorithms for integrating these pharmacotherapies have not been determined, patients undergoing elective PCI were enrolled into 2 distinct and separate studies conducted by the National Investigators Collaborating on Enoxaparin (NICE) study groups (NICE 1 and NICE 4 studies). Patients in NICE 1 were administered enoxaparin 1.0 mg/kg intravenously (without abciximab) and those enrolled in NICE 4 were administered a reduced dose (0.75 mg/kg) of enoxaparin in combination with standard-dose abciximab intravenously during PCI. Bleeding events and ischemic outcomes assessed in-hospital and at 30-days post-PCI were infrequent with either pharmacologic regimen. In the dose regimens studied, enoxaparin with or without abciximab appears to provide safe and effective anticoagulation during PCI. The combination of reduced-dose enoxaparin and abciximab was associated with a low incidence of adverse outcomes (bleeding or ischemic events). Additional studies may be required to establish the relative safety and efficacy of this new adjunctive pharmacologic strategy when compared with the combination of low-dose, weight-adjusted unfractionated heparin and abciximab.

Charcot-Marie-Tooth disease type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP): reliable detection of the CMT1A duplication and HNPP deletion using 8 microsatellite markers in 2 multiplex PCRs

Charcot-Marie-Tooth disease (CMT) and hereditary neuropathy with liability to pressure palsies (HNPP) are the most frequent inherited disorders of the peripheral nervous system. They are clinically and genetically heterogeneous. A submicroscopic tandem duplication of 1. 5 Mb in chromosome 17p11.2-12 comprising the PMP22 gene is found in 70.7% of autosomal dominant Charcot-Marie-Tooth type 1 (CMT1) patients. A reciprocal deletion is found in 87.6% of HNPP patients. The size of the typical CMT1A duplication is too small for classical cytogenetics and the whole region including the CMT1A-REP elements is sometimes too complex for a single DNA analysis method. We present results of a multiplex PCR of 8 microsatellite markers with multicolour fluorescence primer labelling followed by fragment analysis on an ABI 310 Prism analyzer to simplify the diagnostic procedure. Results for 24 patients can be obtained within 24 h. This method was applied on 92 DNA samples of unrelated patients carrying a typical CMT1A duplication previously confirmed by two colour fluorescence in situ hybridization (FISH, probe c132G8) and EcoRI/SacI Southern blotting (probe pLR7.8). Three alleles of three different sizes were clearly detected at least once in 88 of them (95.6%). Subsequently this analysis was applied on 312 Czech patients and revealed a CMT1A/HNPP rearrangement in 109 out of them.

Hereditary motor and sensory neuropathy associated with auditory neuropathy in a Gypsy family

In a Slovene Gypsy family of 19 subjects from four generations three patients with clinical characteristics compatible with hereditary motor and sensory neuropathy - Lom (HMSNL). were found They had severe distal and milder proximal muscle atrophy and weakness with areflexia of myotatic jerks. Two had facial weakness at the time when already wheelchair bound. All sensory modalities were affected distally in the limbs. Sluggish pupillary responses to light and convergence were found. They had skeletal abnormalities. One patient had polydactily on the hand. Nerve conduction studies were compatible with demyelinative polyneuropathy. Nerve biopsy showed mainly axonal loss without hypertrophic changes. Auditory neuropathy was diagnosed in all of them. None of the patients had duplication of 17p1.2-12 or point mutations in the Protein zero. Peripheral myelin protein and Connexin32 genes. Similar disorder that mapped to 8q24 was previously described in some Bulgarian and Italian Gypsy families. Members of our family may suffer from the same hereditary disease and may carry the same ancestor mutation, which was in the past spread in European Gypsy populations.

Combination enoxaparin and abciximab therapy during percutaneous coronary intervention: "NICE guys finish first"

Data from randomized clinical trials support the administration of both enoxaparin and platelet glycoprotein IIb/IIIa blockade to patients who present with non-ST segment evaluation acute coronary syndromes. Enoxaparin does not activate platelets, has a more predictable dose response that facilitates weight-adjusted dosing and may have enhanced antithrombotic (increased anti-Xa activity) and safety (reduced anti-IIa activity) properties when compared with unfractionated heparin. Abciximab administration during percutaneous coronary intervention reduces the incidence of ischemic adverse outcomes and may improve survival in long-term follow-up. The preliminary experience with combining abciximab and intravenous enoxaparin during percutaneous coronary intervention in the NICE-4 Trial demonstrates a low incidence of minor/major bleeding (TIMI definition) and transfusion and infrequent major cardiac events to 30 days follow-up. Future algorithms to facilitate the transition of patients from the clinical service who have received subcutaneous administration of enoxaparin to the cardiac catheterization laboratory prior to percutaneous coronary intervention are forthcoming and will provide seamless integration of "optimal" adjunctive pharmacology through the course of hospitalization for patients with non-ST elevation acute coronary syndromes.

Hereditary auditory, vestibular, motor, and sensory neuropathy in a Slovenian Roma (Gypsy) kindred

Members of a Roma (Gypsy) family with hereditary motor and sensory peripheral neuropathy (HMSN) and concomitant auditory and vestibular cranial neuropathies were identified in Kocevje, Slovenia. The illness begins in childhood with a severe and progressive motor disability and the deafness is delayed until the second decade. There are no symptoms of vestibular dysfunction. The family structure is consistent with an autosomal recessive pattern of inheritance and the genetic locus for the disorder is linked to the same region of chromosome 8q24 as other Roma families with HMSN and deafness from Lom, Bulgaria (HMSN-Lom). The present study shows that the deafness is caused by a neuropathy of the auditory nerve with preserved measures of cochlear outer hair cell function (otoacoustic emissions and cochlear microphonics) but absent neural components of auditory brainstem potentials. The hearing loss affects speech comprehension out of proportion to the pure tone loss. Vestibular testing showed absence of caloric responses. Physiological and neuropathological studies of peripheral nerves were compatible with the nerve disorder contemporaneously affecting Schwann cells and axons resulting in both slowed nerve conduction and axonal loss. Genetic linkage studies suggest a refinement of the 8q24 critical region containing the HMSN-Lom locus that affects peripheral motor and sensory nerves as well as the cranial auditory and vestibular nerves.

Functional organisation of the facial motor system in man

To investigate human corticobulbar projections, electromyographic responses from orbicularis oculi and orbicularis oris muscles were recorded in 11 healthy subjects after transcranial magnetic stimulation. Selective activation of lower facial motoneurones of one hemisphere was reached with the round coil 4 cm lateral to the vertex on a line to the external auditory meatus with stimulus intensities from 45 to 55% (100% = 1.5 T). The mean latency of the OR muscle was 11.5 +/- 1.77 ms contralaterally. Ipsilateral cortical responses were observed in 5 subjects (45%) at a mean latency of 13.88 +/- 2.17 ms. Corticobulbar innervation may have affected bilateral responses in the lower facial muscles as those persisted even after lidocaine blockade of both supraorbital nerves. The functional importance of ipsilateral projections to the lower facial muscles in man is lower than that of the contralateral projections, as evidenced by the fact that they cannot be observed in all subjects or in all motor units. The influence of the trigeminal sensory afferents was excluded from the study after blockade of both supraorbital nerves.

Evidence of direct connection of corticobulbar fibers to orofacial muscles in man: electromyographic study of individual motor unit responses

We studied corticobulbar influence on the orbicularis oris (OR) muscles by anodal and magnetic transcranial stimulation and compared it to the corticospinal influence on first dorsal interosseous muscles of healthy human volunteers. We recorded single motor unit (MU) responses and applied peristimulus time histogram (PSTH) technique to determine their properties. Peaks in the PSTHs are assumed to coincide with multiple excitatory postsynaptic potentials (EPSPs) induced at the motoneurons by corticospinal input. We found relatively small latency variation of consecutive single MU responses for both muscles. Additionally, we found a narrow initial peak in five OR MUs after anodal stimulation. This short duration indicates the presence of monosynaptic cortical projection in the lower facial motoneurons. The EPSP amplitudes, estimated on the basis of initial peak, were used as a measure of the synaptic transmission efficiency. Our results support the concept of predominantly monosynaptic transmission at the spinal level.

Autosomal dominant Charcot-Marie-Tooth disease type 1A and hereditary neuropathy with liability to pressure palsies: detection of the recombination in Slovene patients and exclusion of the potentially recessive Thr118Met PMP22 point mutation

Charcot-Marie-Tooth disease type 1 (CMT1) and hereditary neuropathy with liability to pressure palsies (HNPP) are the most frequent autosomal dominantly inherited disorders of the peripheral nervous system. The recessive inheritance is observed only exceptionally. Unequal crossing-over of misaligned flanking CMT1A-REP elements on chromosome 17p11.2 is the most frequent cause of the CMT1A duplication and of the reciprocal deletion in HNPP patients. Recently a recombination was noted. In our study 71 Slovene CMT1 patients from 36 families, 12 HNPP patients from 6 families and their 31 healthy relatives were analysed for the presence of these recombination mutations. In 29 of 36 unrelated CMT1 (81%) and in all 6 unrelated HNPP patients the duplication or the deletion, on chromosome 17p11.2-12 was detected. In 26 out of 29 duplication patients (CMT1A) (90%) a 3.2 kb EcoRI/SacI duplication junction fragment was observed. The analogous 7.8 kb EcoRI/EcoRI deletion junction fragment was found in 4 out of 6 unrelated HNPP deletion patients (67%). Overall we found a recombination mutation inside the in 86% of unrelated Slovene CMT1A and HNPP patients. One hundred and thirty-six DNA samples of the CMT1 and HNPP patients and of the healthy controls were negative for the potentially recessive Thr118Met PMP22 amino acid substitution. Dominantly inherited CMT1A duplications and HNPP deletions on chromosome 17p11.2 are thus, as in most other European countries, the most common mutations in Slovene CMT1 and HNPP patients. No signs of polymorphism or of potentially recessive mutation were found at the specific Thr118Met PMP22 site.

Genetic epidemiology of Duchenne and Becker muscular dystrophy in Slovenia

Most population studies on Duchenne (DMD) and Becker (BMD) muscular dystrophies predated the discovery of the gene and its product dystrophin. The diagnosis of these conditions and consequent epidemiological estimates were therefore limited to clinical criteria. In our study of the Slovene population the prevalence and cumulative incidence of DMD and BMD were calculated by including additional diagnostic tests: deletion screening in the dystrophin gene as well as dystrophin immunocytochemistry. The minimal prevalence rates, 2.9/100,000 for DMD, 1.2/100,000 for BMD, and the minimal cumulative DMD incidence rate of 13.8/100,000 are in the range of lower estimates compared to studies world-wide. However, we found a high BMD cumulative incidence rate of 5.7/100,000 and a high proportion of BMD versus DMD cumulative incidence rate (41.3%). Our results imply that the epidemiological figures for BMD might have been underestimated in the past.

Correlations between clinical, electrophysiological and genetic findings in hereditary motor and sensory neuropathy type I (HMSN I)

We evaluated the correlation between clinical signs, electrophysiological data and molecular genetics findings in patients with HMSN I. We found a duplication in the PMP-22 gene in 60% of HMSN I families. We compared clinical and electrophysiological data between 23 patients with duplication and 18 patients without duplication. No statistically significant differences in age of onset of symptoms, clinical signs and electrophysiological parameters were found.

CTG repeat analysis in lymphocytes, muscles and fibroblasts in patients with myotonic dystrophy

The mutation responsible for DM has been identified as the amplification of a polymorphic (CTG)n repeat in the 3' untranslated region of the myotonin proteinase gene. To examine somatic instability of the repeat, we studied tissue variability of the CTG expansion of three mesodermally derived tissues: lymphocytes, cultured fibroblasts and muscle cells. In six patients with adult onset DM, the repeat region was larger in skeletal muscles and fibrolasts as compared to lymphocytes. Our findings indicate that somatic CTG instability between examined tissues might take place postnatally by a selection mechanism in lymphocytes.

Cardiac involvement in Emery-Dreifuss muscular dystrophy: role of a diagnostic pacemaker

Emery-Dreifuss muscular dystrophy is an X-linked recessive myopathy. Its progression is slow, and it rarely leads to cessation of walking; therefore, it has often been called "benign." On the other hand, cardiac involvement is often severe and sudden death is not uncommon. We describe a family with four affected males, two of whom died suddenly. The case of an affected man with first-degree AV block, incomplete right bundle branch block, and left anterior fascicular block is described in detail. The prophylactic insertion of a diagnostic pacemaker enabled us to follow the progress of conduction disturbances without leaving the patient unprotected. While AV and intraventricular conduction defects were more prominent before pacemaker implantation, sinus node dysfunction became more important during the follow-up.

Botulinum toxin in the treatment of neurological disorders

Botulinum toxin therapy is safe and effective in the treatment of different movement disorders, especially focal dystonias. We reviewed botulinum toxin treatment of 97 patients: 36 had blepharospasm, 41 had torticollis, and 20 had diverse movement disorders. Patients with blepharospasm and torticollis improved markedly after botulinum toxin injections. The most common side effect in BS patients was ptosis (44.4%); in TC patients, it was dysphagia (29.3%). The mean duration of the improvement in both groups was 3.4 months. Very promising results were obtained also in the heterogeneous group including patients with other focal dystonias and cerebral palsy. On the basis of these results, we concluded that BTA injections must now be considered the mainstay of therapy for focal dystonias and other involuntary movement disorders.

Facioscapulohumeral dystrophy: jitter in facial muscles

Motor end plate jitter was studied by single fibre EMG in the orbicularis oculi muscle of eight patients with facioscapulohumeral dystrophy activated by extramuscular nerve stimulation. The jitter was found to be slightly larger in comparison with the normal controls, although still within the normal limits in each patient. The findings are considered to indicate absence of any significant neuromuscular transmission disturbance, inflammatory or regenerative process, or reinnervation in progress. There was no evidence of muscle fibre conduction abnormality even in very weak muscle.

Lumbosacral evoked potentials (LSEPs) and cortical somatosensory evoked potentials (SEPs) in patients with lesions of the conus medullaris and cauda equina

Evoked potentials from unilateral stimulation of the posterior tibial nerve at the knee were recorded over the spinous processes S1, L4, L2, T12 and from the 'lower extremity' portion of the sensory cortex (Cz) in 29 patients who exhibited clinical and electromyographic signs of conus medullaris or cauda equina lesions. Simultaneous recording of the lumbosacral evoked potentials (LSEPs) and cortical somatosensory evoked potentials (SEPs) permitted evaluation of the relative effectiveness of the peripheral stimulus in eliciting responses in the lumbosacral segments of the spinal cord and in the cortex of the brain. In patients with cauda equina lesion, each major component of LSEP can be absent or the peak can have a reduced amplitude and a prolonged latency. The degree of impairment of the LSEP runs in parallel to the degree of severeness of the cauda equina lesion. The recording of LSEP responses with surface electrodes represents a reliable test for the detection of mild cauda equina abnormalities, but the surface recording technique is not sensitive enough to differentiate between severe incomplete and severe complete cauda equina lesions. On the other hand, concurrent recording of responses evoked at lumbosacral and cortical levels by the same stimuli did detect instances in which the first-order afferents were capable of delivering an adequate volley of impulses to evoke a sizeable cortical response without evidence of an associated postsynaptic response in the spinal cord. Such findings are good evidence of a problem localized in the gray matter of the spinal cord.(ABSTRACT TRUNCATED AT 250 WORDS)

Pudendal nerve involvement in patients with hereditary motor and sensory neuropathy

Pudendal nerve involvement was demonstrated by electromyography of perineal muscles and by recordings of their direct and reflex responses on perineal electrical stimulation in 10 patients with hereditary motor and sensory neuropathy. Patients reported no defecation disturbances and the 6 men had good erections. Urinary stress incontinence was seen in those 2 (of 4) female patients who had delivered.

Percutaneous stimulation of human corticospinal tract: a single-fibre EMG study of individual motor unit responses

The technique of electrical stimulation of the brain through intact scalp was applied to activate the corticospinal tract (CST) of healthy human volunteers. Single motoneurone responses were picked up by a special (single fibre EMG) needle electrode. Our finding of relatively small latency variation of consecutive single motor unit responses seems to support the concept of predominantly monosynaptic transmission at the spinal level. The alternation between several discrete latencies seems to reflect a complexly shaped spinal motoneurone excitatory postsynaptic potential (EPSP), which could be due to either alternating direct/indirect (via other cerebral neurones) activation of the corticospinal tract (CST) neurones, or alternating mono- or oligosynaptic transmission at the spinal level, or multiple CST impulses in response to a single stimulus.