The effects of interstimulus interval on sensory gating and on preattentive auditory memory in the oddball paradigm: Can magnitude of the sensory gating affect preattentive auditory comparison process?

P50, and mismatch negativity (MMN) are components of event-related potentials (ERP) reflecting sensory gating and preattentive auditory memory, respectively. Interstimulus interval (ISI) is an important determinant of the amplitudes of these components and N1. In the present study the interrelation between stimulus gating and preattentive auditory sensory memory were investigated as a function of ISI in 1.5, 2.5 and 3.5 s in 15 healthy volunteered participants. ISI factor affected the N1 peak amplitude significantly. MMN amplitude in 2.5 s ISI was significantly smaller compared to 1.5 and 3.5 s ISI. ISI X stimuli interaction on P50 amplitude was statistically significant. P50 amplitudes to deviant stimuli in 2.5 s ISI were larger than the P50 amplitudes in other ISIs. P50 difference (P50d) waveform amplitude correlated significantly with MMN amplitude. The results suggest that: (i) auditory sensory gating could affect preattentive auditory sensory memory by supplying input to the comparator mechanism; (ii) 2.5 s ISI is important in displaying the sensory gating and preattentive auditory sensory memory relation.     

Effects of physiological aging on mismatch negativity: A meta-analysis

Mismatch negativity (MMN) is a promising window on how the functional integrity of auditory sensory memory and change discrimination is modulated by age and relevant clinical conditions. However, the effects of aging on MMN have remained somewhat elusive, particularly at short interstimulus intervals (ISIs). We performed a meta-analysis of peer-reviewed MMN studies that had targeted both young and elderly adults to estimate the mean effect size. Nine studies, consisting of 29 individual investigations, were included and the final total study population consisted of 182 young and 165 elderly subjects. The effects of different deviant types and duration of ISIs on the effect size were assessed. The overall mean effect size was 0.63 (95% CI at 0.43–0.82). The effect sizes for long ISI (> 2 s, effect size 0.68, 95% CI at 0.31–1.06) and short ISI (< 2 s, effect size 0.61, 95% CI at 0.39–0.84) were both considered moderate. A further analysis showed a prominent aging-related decrease in MMN responses to duration and frequency changes at short ISIs. It was also interesting to note that the effect size was about 25% larger for duration deviant condition compared to the frequency deviant condition. In conclusion, a reduced MMN response to duration and frequency deviants is a robust feature among the aged adults, which suggests that there has been a decline in the functional integrity of central auditory processing in this population.     

Temporal characteristics of auditory sensory memory: Neuromagnetic evidence

We investigated the temporal dependencies of N100m, the most prominent deflection of the auditory evoked response, using whole-head neuromagnetic recordings. Stimuli were presented singly or in pairs (tones in the pair were separated by 210 ms) at interstimulus intervals (ISIs) of 0.6–8.1 s. N100m to single stimuli and to the first tone of the pair had similar temporal recovery functions, plateauing at ISIs of 6 s. N100m to the second tone in the pair, which was smaller than that to the first except with short ISIs, plateaued with ISIs of about 4 s. Source analysis revealed that the N100m could be decomposed into two sources separated by about 1 cm on the supratemporal plane. The recovery function of the posterior source was not affected by stimulus presentation, whereas that of the anterior source was. Activity in the anterior area appears to reflect the effects of temporal integration. We relate these results to auditory sensory memory.     

Long-term adherence to the Mediterranean diet reduces the prevalence of hyperuricaemia in elderly individuals, without known cardiovascular disease: the Ikaria study

Background

The purpose of this study was to evaluate the impact of adherence to Mediterranean diet on serum uric acid (UA) levels in elderly individuals, without known cardiovascular disease.

Methods

During 2009, 281 females (75 ± 6 years old) and 257 males (75 ± 7 years old) permanent inhabitants of the island, were voluntarily enrolled. A diet score that assesses the inherent characteristics of the Mediterranean diet (MedDietScore, range 0-55) was applied. Serum levels of UA were determined using an enzymatic colorimetric test through the uricase-peroxidase method. Hyperuricaemia was defined as UA > 7 mg/dL in males and 6 mg/dL in females.

Results

Prevalence of hyperuricaemia was 34% in males and 25% in females (p = 0.02). Mean level of adherence to the Mediterranean diet was 35 ± 2. Linear regression analysis revealed that MedDietScore was inversely associated with UA levels (b ± SE: −1.48 ± 0.17, p < 0.001) in the overall sample, after controlling for hypertension, hypercholesterolemia, diabetes mellitus, creatinine clearance, physical activity, and coffee consumption. When the analysis was stratified by gender, MedDietScore was inversely associated with UA levels in males (b ± SE: −1.10 ± 0.42, p = 0.009), but not in females (b ± SE: 0.04 ± 0.41, p = 0.92).

Conclusion

Another cardioprotective effect of Mediterranean diet was revealed, through the modification of UA levels in elderly individuals. The potential different effect size as regards the relationship between diet and UA levels between genders, deserves further investigation.     

Working memory capacity affects the interference control of distractors at auditory gating

It is important to understand the role of individual differences in working memory capacity (WMC). We investigated the relation between differences in WMC and N1 in event-related brain potentials as a measure of early selective attention for an auditory distractor in three-stimulus oddball tasks that required minimum memory. A high-WMC group (n = 13) showed a smaller N1 in response to a distractor and target than did a low-WMC group (n = 13) in the novel condition with high distraction. However, in the simple condition with low distraction, there was no difference in N1 between the groups. For all participants (n = 52), the correlation between the scores for WMC and N1 peak amplitude was strong for distractors in the novel condition, whereas there was no relation in the simple condition. These results suggest that WMC can predict the interference control for a salient distractor at auditory gating even during a selective attention task.     

Rats subjected to chronic-intermittent hypoxia have increased density of noradrenergic terminals in the trigeminal sensory and motor nuclei

Rodents subjected to chronic intermittent hypoxia (CIH) are used to investigate the mechanisms underlying the consequences of the obstructive sleep apnea (OSA) syndrome. Following CIH, rats have an increased density of noradrenergic terminals in the hypoglossal motor nucleus which innervates lingual muscles that protect the upper airway from collapse in OSA patients. Here, we investigated whether such an increase also occurs in other brainstem nuclei. Six pairs of male Sprague-Dawley rats were exposed to CIH or sham treatment for 10 h/day for 35 days, with O₂ level oscillating between 24% and 7% every 3 min. Brainstem sections were immunohistochemically processed for dopamine-β-hydroxylase, a marker for norepinephrine. Noradrenergic terminal varicosities were counted in the center of the trigeminal motor nucleus (Mo5) and the interpolar part of the spinal trigeminal sensory nucleus (Sp5). In the Mo5, noradrenergic varicosities tended to be 9% more numerous in CIH- than sham-treated rats, and in the Sp5 they were 18% more numerous in CIH rats (184 ± 9 vs. 156 ± 8 per 100 × 100 μm counting box; p = 0.03, n = 18 section pairs).These data suggest that CIH elicits sprouting of noradrenergic terminals in multiple motor and sensory regions of the lower brainstem. This may alter motor and cardiorespiratory outputs and the transmission of cardiorespiratory and motor reflexes in CIH rats and, by implication, in OSA patients.     

Insufficient sleep impairs driving performance and cognitive function

Cumulative sleep deprivation may increase the risk of psychiatric disorders, other disorders, and accidents. We examined the effect of insufficient sleep on cognitive function, driving performance, and cerebral blood flow in 19 healthy adults (mean age 29.2 years). All participants were in bed for 8 h (sufficient sleep), and for <4 h (insufficient sleep). The oxyhaemoglobin (oxyHb) level by a word fluency task was measured with a near-infrared spectroscopy recorder on the morning following sufficient and insufficient sleep periods. Wisconsin card sorting test, continuous performance test, N-back test, and driving performance were evaluated on the same days. The peak oxyHb level was significantly lower, in the left and right frontal lobes after insufficient sleep than after sufficient sleep (left: 0.25 ± 0.13 vs. 0.74 ± 0.33 mmol, P < 0.001; right: 0.25 ± 0.09 vs. 0.69 ± 0.44 mmol, P < 0.01). The percentage of correct responses on CPT after insufficient sleep was significantly lower than that after sufficient sleep (96.1 ± 4.5 vs. 86.6 ± 9.8%, P < 0.05). The brake reaction time in a harsh-braking test was significantly longer after insufficient sleep than after sufficient sleep (546.2 ± 23.0 vs. 478.0 ± 51.2 ms, P < 0.05). Whereas there were no significant correlations between decrease in oxyHb and the changes of cognitive function or driving performance between insufficient sleep and sufficient sleep. One night of insufficient sleep affects daytime cognitive function and driving performance and this was accompanied by the changes of cortical oxygenation response.     

Olfactory loss and nigrostriatal dopaminergic denervation in the elderly

Olfactory dysfunction may precede common neurodegenerative disorders in the elderly, such as Alzheimer (AD) or Parkinson disease (PD). However, pathobiological mechanisms of olfactory loss in the elderly are poorly understood. Although nigrostriatal dopaminergic denervation is a key patholobiological feature of PD, age-associated nigrostriatal denervation (AASDD) occurs also with normal aging and can be more prominent in some elderly. We investigated the relationship between AASDD and olfactory performance in community-dwelling subjects. Community-dwelling subjects (n = 73, 44 F/29 M, mean age 64.0 ± 16.4, range 20–85) underwent brain dopamine transporter (DAT) [¹¹C]2-β-carbomethoxy-3β-(4-fluorophenyl) tropane (β-CFT) positron emission tomography (PET) imaging and olfactory assessment using the 40-odor University of Pennsylvania Smell Identification Test (UPSIT). Subjects with clinical or DAT PET evidence of Parkinson disease (PD) were not eligible for the study. AASDD was defined based on normative data in young and middle-aged subjects. Compared to a mild and general linear decline in odor identification observed in most subjects (R² = 0.18, P = 0.0002), there were 13 subjects who deviated below the 5% confidence interval level in age-predicted UPSIT scores. Analysis limited to elderly subjects 60 years and over demonstrated a significant association between poor smell (n = 10 out of 49, 20.4%) and AASDD (χ² = 4.4, P < 0.05). There is a significant association between olfactory dysfunction and more prominent nigrostriatal denervation in the elderly. Olfactory assessment may have potential as a screening tool to detect age-accelerated neurodegeneration in the elderly.     

Occipital cortex activation studied with simultaneous recordings of functional transcranial Doppler ultrasound (fTCD) and visual evoked potential (VEP) in cognitively normal human subjects: Effect of healthy aging

We evaluated effect of aging, gender and eye (sighting) dominance on relationship between visual evoked flow response (VEFR) and visual evoked potential (VEP), which refers to neurovascular coupling. The VEFR was defined as a percentage increase of the ratio of mean blood flow velocity in the contralateral (according to the side of dominant eye processing) posterior cerebral artery P2 segment to those in ipsilateral middle cerebral artery from the baseline during half-field stimulation. Vasoneural coupling index (CI) was defined as “100 × VEFR/VEP P100 amplitude”. Compared to the healthy elderly subjects (n: 19; female/male: 6/13, mean age: 69.7 ± 7), younger participants (n: 28; female/male: 16/12; mean age: 31.1 ± 4.7) had significantly higher VEFR for both sides: 18.9 ± 6.7% versus 11.2 ± 6.7%, p < 0.001 and 17.3 ± 7.7% versus 11.8 ± 5.5%, p: 0.007, for the hemisphere contralateral to dominant and nondominant eye (D and ND side), respectively. Albeit absence of any correlation between their latencies, VEP and VEFR amplitudes were well correlated. However, this was significant only for younger subjects and more evident in D side. The CI was higher in young subjects compared to those in old ones (6.49 ± 2.79 versus 4.75 ± 2.35, respectively, p = 0.007). But, this age-related trend remained as borderline when sides were analyzed individually: In the young subjects CI was 5.99 ± 2.21 and 6.96 ± 3.22 for D and ND sides, while those were 4.27 ± 2.60 and 5.19 ± 2.07 in old ones. This study confirmed diminished visual evoked flow in relation with advancing age, and suggested that “weakened” neurovascular coupling (as evidenced by a decreased VEP and VEFR correlation along with decreased CI) as one of the underlying mechanisms.     

Early event-related potentials changes during simple mental calculation in Chinese older adults with mild cognitive impairment: A case–control study

The aim was to examine early event-related potential (ERP) changes during mental arithmetic calculation task in mild cognitive impairment patients compared to healthy elderly. 16 mild cognitive impairment (MCI) subjects and 16 healthy Chinese older adults were studied. Event-related potentials were elicited using a simple mental calculation task. Performance on arithmetic calculation task, and the latency and amplitude of early event-related potential components (N1, P1, N170, and P2) were compared between the two groups. The reaction time of MCI group was significantly longer than that of control group (1691.03 ± 94.59 vs. 1539.55 ± 27.76, P < 0.01). The correct rate of MCI group (0.9463 ± 0.04) was significantly lower than that of control group (0.9776 ± 0.02, P < 0.01). The latency of temporal–occipital N170 and central–prefrontal P2 of MCI group were significantly prolonged compared to controls. MCI subjects presented significantly higher P2 amplitude. Compared with healthy controls, N170 was significantly lower at left temporal–occipital region and higher at right temporal–occipital region in mild cognitive impairment. Mild cognitive impairment patients had deficit on simple calculation. The early arithmetic calculation processing mechanism of mild cognitive impairment patients may be different from normal people.     

Generalizability of perturbation-evoked cortical potentials: Independence from sensory,motor and overall postural state

Following disturbances to postural stability, balance recovery reactions are evoked by numerous sensory inputs and characterized by motor reactions involving different patterns of activity, depending on postural task conditions. It remains unknown whether well-documented cortical responses to instability share common spatio-temporal characteristics, despite variations in the sensory, motor, and postural components of the reactions. The objective was to explore the spatio-temporal profile of cortical potentials evoked by instability requiring either upper- or lower-limb compensatory responses. The hypothesis that upper- and lower-limb balance-correcting reactions are associated with evoked cortical potentials (N1, P2) featuring similar spatio-temporal characteristics was tested by inducing postural perturbations in seated (SIT) or standing (STAND) positions. For both conditions, N1 amplitude was greatest at FCz, with no significant differences in the timing of N1 peak (SIT: 142.4 ± 7.95 ms; STAND: 148.4 ± 4.10 ms) or N1 amplitude (SIT: 37.16 ± 6.99 μV; STAND: 39.08 ± 4.51 μV). The amplitude of the P2 potential (measured at CPz) was significantly larger in the STAND condition (37.87 ± 6.14 μV) than in the SIT (23.66 ± 6.21 μV) condition. Significant differences in P2 peak time between tasks were absent (SIT: 319.9 ± 11.45 ms; STAND: 322.7 ± 7.61 ms). Though differences in the amplitude of components of evoked potentials may reflect the extent of cortical involvement in different aspects of postural control, similarities in the spatio-temporal components of cortical potentials between tasks reflects generalizable cortical processing of unexpected stimuli independent of the sensory, motor, or postural aspects of the response.     

Respiratory pattern in awake rats: Effects of motor activity and of alerting stimuli

Our aim was to assess the impact of motor activity and of arousing stimuli on respiratory rate in the awake rats. The study was performed in male adult Sprague-Dawley (SD, n = 5) and Hooded Wistar (HW, n = 5) rats instrumented for ECG telemetry. Respiratory rate was recorded using whole-body plethysmograph, with a piezoelectric sensor attached for the simultaneous assessment of motor activity. All motor activity was found to be associated with an immediate increase in respiratory rate that remained elevated for the whole duration of movement; this was reflected by: i) bimodal distribution of respiratory intervals (modes for slow peak: 336 ± 19 and 532 ± 80 ms for HW and SD, p < 0.05; modes for fast peak 128 ± 6 and 132 ± 7 ms for HW and SD, NS); and ii) a tight correlation between total movement time and total time of tachypnoea, with an R² ranging 0.96-0.99 (n = 10, p < 0001). The extent of motor-related tachypnoea was significantly correlated with the intensity of associated movement. Mild alerting stimuli produced stereotyped tachypnoeic responses, without affecting heart rate: tapping the chamber raised respiratory rate from 117 ± 7 to 430 ± 15 cpm; sudden side move — from 134 ± 13 to 487 ± 16 cpm, and turning on lights — from 136 ± 12 to 507 ± 14 cpm (n = 10; p < 0.01 for all; no inter-strain differences). We conclude that: i) sniffing is an integral part of the generalized arousal response and does not depend on the modality of sensory stimuli; ii) tachypnoea is a sensitive index of arousal; and iii) respiratory rate is tightly correlated with motor activity.     

Differential cerebrovascular CO2 reactivity in anterior and posterior cerebral circulations

The potential differences in cerebrovascular responses between the anterior and posterior circulations to changes in CO₂ are unclear in humans. Using transcranial Doppler ultrasound, we compared the CO₂ reactivity of the (1) BA and PCA and (2) MCA and PCA during hyperoxic rebreathing in supine position. The reactivity in the BA and PCA was similar in both absolute (1.27 ± 0.5 and 1.27 ± 0.6 cm/s/Torr; P = 0.992) and relative (3.98 ± 1.3 and 3.66 ± 1.5%/Torr CO₂; P = 0.581) measures, suggesting that the PCA is an adequate surrogate measure of reactivity for the BA. The MCA reactivity was greater than the PCA in absolute (2.09 ± 0.7 and 1.22 ± 0.5 cm/s/Torr CO₂; P < 0.001), but not relative measures (3.25 ± 1.0 and 3.56 ± 1.6%/Torr CO₂; P = 0.629). Our findings (a) confirm regional differences in the absolute reactivity in the human brain and (b) suggest that in cerebrovascular studies investigating functions mediated by posterior brain structures (e.g., control of breathing), the posterior vasculature should also be insonated.     

Role of hepatic HCV-RNA level on the severity of chronic hepatitis C and response to antiviral therapy

Background

Correlation between hepatic HCV-RNA and serum HCV-RNA, severity of liver disease and response to therapy is poorly known.

Objectives

To assess the influence of hepatic HCV-RNA level on severity of liver disease and response to therapy in a large cohort of chronic hepatitis C (CHC) patients.

Study Design

HCV-RNA was measured in frozen liver biopsies and serum samples from 130 CHC patients the day of liver biopsy prior to treatment. Liver fibrosis was assessed by Ishaq scoring. A Sustained Virological Response (SVR) was observed in 52% of the patients, non-response (NR) in 34%.

Results

Mean ± standard deviation hepatic HCV-RNA level was 7.69 ± 0.67 log₁₀ copies/mg of liver. Mean serum HCV-RNA level was 6.21 ± 0.72 log₁₀ copies/ml. There was a correlation between hepatic and serum HCV-RNA in genotype 1 and 4 (p = 0.008 and p = 0.03) and age (p = 0.006). Mean hepatic HCV-RNA was 7.70 ± 0.69 vs 7.67 ± 0.68 log₁₀ copies/mg of liver, in patients with significant fibrosis vs those with mild fibrosis, respectively (p = 0.7); 8.04 ± 0.68; 7.44 ± 0.47; 7.43 ± 0.49 and 7.44 ± 0.71 log₁₀ copies/mg of liver in genotypes 1, 2, 3 and 4, respectively (p = 0.0001); higher in women than in men (p = 0.04); 7.60 ± 0.63, 7.71 ± 0.54 and 7.96 ± 0.73 log₁₀ copies/mg in SVR, relapsers and NR, respectively (p = 0.1). Multivariate analysis showed that high hepatic HCV-RNA level was independently associated with genotype and response to therapy was associated with genotype independently from hepatic HCV-RNA level.

Conclusions

Hepatic HCV-RNA level was not associated with severity of liver disease. High level was strongly associated with HCV genotype independently from response to therapy.     

Communication skills instruction: An analysis of self, peer-group, student instructors and faculty assessment

Objective

To explore the correlation of student and faculty assessments of, second-year dental students’ (D2s) communicative skills during simulated patient interviews.

Methods

Eighty-two D2s, 14 student instructors and 8 faculty used a 5-point scale, (1 = poor-5 = excellent) to assess 12 specific communicative skills of D2s generating assessment sources of self, peer-group, student instructor, and faculty. Mean scores and comparisons between assessment sources were calculated. Spearman correlations evaluated relationships between specific skills and assessment sources.

Results

Mean assessment score and standard error for peer-group (4.14 ± 0.04), was higher than self (3.86 ± 0.06, p < 0.05) yet slightly higher than student instructor (4.07 ± 0.04) and faculty (3.93 ± 0.10). Regarding assessment sources, the degree of correlation from highest to lowest was peer-group and student instructor (ρ = 0.46, p < 0.0001), self and student instructor (ρ = 0.35, p < 0.002), self and peer-group (ρ = 0.28, p < 0.02). The correlations between student instructor and faculty, faculty and self, and faculty and peer-group were nonsignificant.

Conclusion

Student assessments were different from faculty by mean score and correlation index. Future studies are needed to determine the nature of the differences found between student and faculty assessments.

Practice implications

Peer, student instructor and faculty assessments of dental students’ communicative skills are not necessarily interchangeable but may offer uniquely different and valuable feedback to students.     

Increased Toll-like receptor 9 expression by B cells from inflammatory bowel disease patients

Background

Toll-like receptors (TLRs) are important mediators of the innate immune response. Our aim was to evaluate TLR9 expression in peripheral B cells, taken from inflammatory bowel disease (IBD) patients before and after anti-inflammatory treatment. Nineteen patients with IBD (12-crohn’s disease, 7-ulcerative colitis) and 18 healthy controls were included in the study. Disease severity was assessed using the Pediatric/Adults crohn’s disease activity index and the ulcerative colitis activity index as needed. Accordingly, patients were classified as mild, moderate or severe disease. Peripheral B cells isolated from IBD patients, before and after anti-inflammatory treatment, and from the control group, were cultured for 24 h with and without CpG oligodeoxynucleotides (ODN-CpG) 0.5 μM. TLR9 expression by memory B cells (CD19+CD27+) was assessed by flow cytometry.

Results

We found that TLR9 expression by peripheral B cells was significantly higher in IBD patients than that in healthy controls (12.42 ± 9.5 MFI vs. 6.0 ± 2.6 MFI p = 0.02). The addition of ODN-CpG to B cells resulted in a significantly increase of TLR9 expression in B cells from healthy controls (6.5 ± 3.2 MFI vs. 8.8 ± 4.2 MFI p = 0.007). On the contrary, B cells from IBD patients only partly respond to the addition of ODN-CpG after anti-inflammatory treatment (6.3 ± 3.8 vs. 7.3 ± 3.7, p = 0.1). TLR9 expression was positively correlated with IBD disease severity (r = 0.681, p < 0.0001).

Conclusions

TLR9 expression in memory B from IBD patients is elevated and associated with disease severity.     

Aging-related changes in auditory and visual integration measured with MEG

As noted in the aging literature, processing delays often occur in the central nervous system with increasing age, which is often attributable in part to demyelination. In addition, differential slowing between sensory systems has been shown to be most discrepant between visual (up to 20 ms) and auditory systems (<5 ms). Therefore, we used MEG to measure the multisensory integration response in auditory association cortex in young and elderly participants to better understand the effects of aging on multisensory integration abilities. Results show a main effect for reaction times (RTs); the mean RTs of the elderly were significantly slower than the young. In addition, in the young we found significant facilitation of RTs to the multisensory stimuli relative to both unisensory stimuli, when comparing the cumulative distribution functions, which was not evident for the elderly. We also identified a significant interaction between age and condition in the superior temporal gyrus. In particular, the elderly had larger amplitude responses (∼100 ms) to auditory stimuli relative to the young when auditory stimuli alone were presented, whereas the amplitude of responses to the multisensory stimuli was reduced in the elderly, relative to the young. This suppressed cortical multisensory integration response in the elderly, which corresponded with slower RTs and reduced RT facilitation effects, has not been reported previously and may be related to poor cortical integration based on timing changes in unisensory processing in the elderly.     

Cyclic alternating pattern and sleep quality in healthy subjects—Is there a first-night effect on different approaches of sleep quality?

Objective

Cyclic alternating pattern (CAP) is defined as periodic EEG activity during NREM sleep that reflects unstable sleep and represents a marker of instability of the sleep process. The aim of the present investigation was to analyze sleep quality of 28 healthy subjects (mean age 53.3 ± 21.3 years) over two consecutive nights and determine potential differences between them (“first-night effect”).

Methods

Evaluations comprised objective and subjective sleep variables as well as macrostructural and microstructural variables of sleep.

Results

Macrostructural analysis showed significant differences between the first and the second sleep laboratory night in REM latency (122.39 ± 60.46 min vs. 95.43 ± 36.60 min; T = 3.431; p = 0.002) and the amount of sleep stage 1 (42.60 ± 21.80 min vs. 39.70 ± 18.95 min; T = 2.223; p = 0.035). Microstructural analysis revealed a significant decrease in the CAP rate (1st night: 33.29%; 2nd night: 26.34%; T = 3.288; p = 0.003) and in the amount of subtype A2 (74.79 ± 43.47 vs. 58.50 ± 23.22; T = 2.185; p = 0.038). Subjective variables also demonstrated a significant increase of drive (T = 2.564; p = 0.016).

Conclusion

Healthy subjects show hardly any macrostructural differences between the first and the second night in the sleep laboratory. On the microstructural level differences in CAP variables were found.

Significance

Microstructural analysis can be seen as a further approach to the classification of sleep and CAP turned out to be sensitive to environmental influences on sleep.     

Brain activity in goal-directed movements in a real compared to a virtual environment using the Nintendo Wii

Low budget virtual environments like the Nintendo Wii increased in popularity and may play a role in motor learning related to sports and exercise. But nothing was known about the comparability of cortical activity of motor tasks in real and virtual environments. The aim of the study was to examine cortical differences between real and Wii based virtual sports performances using the golf putt as a model. Ten male golfers (26.0 ± 0.7 years; 81.8 ± 5.6 kg; 184.5 ± 6.0 cm; handicap 30.0 ± 10.0; 2.9 ± 1.0 years of golf experience) were asked to putt for 3 min in random order in the real and the virtual Wii condition. A rest in sitting position (3 min) followed each performance. The score and cortical activity (EEG) were recorded continuously. The participants performed with a significant better score in the real condition (p ≤ 0.01). Compared to virtual putting Theta spectral power showed a significant increase during real performance at F3 and F4 (p ≤ 0.05). Significantly increased Alpha-2 power was demonstrated during real putting compared to the virtual putting performance at P3 (p ≤ 0.05). The findings suggested that putting performance and brain activity was influenced by the choice of a real or virtual environment. The results were discussed based on the concept of the working memory where increased frontal Theta power indicated higher focused attention and higher Alpha-2 power was inversely related to the quantity of sensory information processing in the real putting compared to the virtual condition.     

The effect of a monoclonal antibody to calcitonin-gene related peptide (CGRP) on injury-induced ectopic discharge following lingual nerve injury

The development of ectopic neural discharge at a site of peripheral nerve injury is thought to contribute to the initiation of sensory disturbances and pain. We have previously shown that this discharge can be initiated or increased by the neuropeptide calcitonin gene-related peptide (CGRP). We have now studied a potential therapeutic approach to reducing the discharge by evaluating the effect of a systemically administered monoclonal antibody to CGRP on injury-induced activity in the lingual nerve. In 16 anaesthetised adult ferrets the left lingual nerve was sectioned. One day after the injury, the animals received a subcutaneous injection of either a monoclonal antibody to CGRP or a vehicle control. Three days after the injury, under a second anaesthetic, single-unit electrophysiological recordings were made from central to the injury site (469 and 391 units were analysed in antibody and vehicle groups, respectively), and the proportion of units that were spontaneously active was determined. In the vehicle-treated animals 6.4 ± 2.7 [SEM]% of the units were spontaneously active, with conduction velocities of 8.8-40.8 m/s and discharge frequencies of 0.03-2.7 Hz. In the monoclonal antibody-treated animals 5.7 ± 2.0% of the units were spontaneously active, with conduction velocities of 13.9-38.8 m/s and discharge frequencies of 0.07-1.8 Hz. There was no significant difference between these two groups (for spontaneous activity and conduction velocity: p > 0.05, Student's t-test; for discharge frequency: p > 0.05, Mann-Whitney test), suggesting that the spontaneous activity initiated by a nerve injury cannot be modulated by administration of a monoclonal antibody to CGRP.