REM sleep and depressive symptoms in a population‐based study of middle‐aged and elderly persons

Alterations in rapid eye movement sleep have been consistently related to depression in clinical studies. So far, there is limited evidence from population‐based studies for this association of rapid eye movement sleep alterations with depressive symptoms. In 489 participants of the Rotterdam Study, we assessed rapid eye movement sleep latency, rapid eye movement sleep duration and rapid eye movement density with ambulant polysomnography, and depressive symptoms with the Center of Epidemiologic Studies‐Depression Scale. A longer rapid eye movement sleep latency (B = 0.002, P = 0.025) and higher rapid eye movement density (B = 0.015, P = 0.046) were related to depressive symptoms after age–sex adjustment. When we excluded persons who used sleep medication or medication for the nervous system (n = 124), only rapid eye movement density remained related to depressive symptoms (B = 0.018, P = 0.027). Our results suggest that rapid eye movement density is a marker of depressive symptoms in the general population, and that associations of rapid eye movement sleep with depressive symptoms are modified by the use of medication.     

Sleep patterns and insomnia in a large population‐based study of middle‐aged and older adults: The Tromsø study 2015–2016

Epidemiological studies assessing adult sleep duration have yielded inconsistent findings and there are still large variations in estimation of insomnia prevalence according to the most recent diagnostic criteria. Our objective was to describe sleep patterns in a large population of middle‐aged and older adults, by employing accurate measures of both sleep duration and insomnia. Data stem from the Tromsø Study (2015–2016), an ongoing population‐based study in northern Norway comprising citizens aged 40 years and older (n = 21,083, attendance = 64.7%). Sleep parameters were reported separately for weekdays and weekends and included bedtime, rise time, sleep latency and total sleep time. Insomnia was defined according to recent diagnostic criteria (International Classification of Sleep Disorders; ICSD‐3). The results show that 20% (95% confidence interval,19.4–20.6) fulfilled the inclusion criteria for insomnia. The prevalence was especially high among women (25%), for whom the prevalence also increased with age. For men, the prevalence was around 15% across all age groups. In all, 42% of the women reported sleeping <7 hr (mean sleep duration of 7:07 hr), whereas the corresponding proportion among males was 52% (mean sleep duration of 6:55 hr). We conclude that the proportion of middle‐aged and older adults not getting the recommended amount of sleep is worryingly high, as is also the observed prevalence of insomnia. This warrants attention as a public health problem in this population.     

A comparative study of magnetic resonance imaging on the gray matter and resting‐state function in prodromal and first‐episode schizophrenia

It is very difficult to predict the future development possibility of schizophrenia through the clinical symptoms of the high‐risk cases. Therefore, how to determine the possibility of developing into schizophrenia individuals before the onset of the diseases are particularly important. The study investigated cerebral gray matter volume differences and resting‐state functional connections among patients with psychosis risk syndrome (PRS), patients with first‐episode schizophrenic (FES), and healthy controls (HC), aiming to provide scientific clinical evidence for schizophrenia early identification and intervention. A total of 19 PRS patients, 18 FES patients, and 29 HC were recruited. Gray matter volume and amplitude of low‐frequency fluctuation (fALFF) during resting‐state functional studies were measured. Comparison of gray matter volumes showed that PRS and FES groups had common reduced gray matter volume in the right caudate. PRS and FES patients showed altered connectivity mainly in the semantic processing‐related brain areas. fALFF analysis found that PRF and FES patients had significant differences in fALFF values of the brain region mainly located in the subcortical network, visual recognition network, and auditory network. In addition, PRF individuals had a higher fALFF value and a lower fALFF value in the anterior wedge of the cerebral network than the HC group. Gray matter volume loss between related brain areas might appear prior to illness onset. Similar fALFF values occurred in PRS and FES groups indicated that multiple brain regions of neuronal activity abnormalities and unconventional neural network mechanism have been existed in PRS patients.     

Increased interhemispheric resting‐state functional connectivity in functional dyspepsia: a pilot study

Recent brain imaging studies have emphasized the role of regional brain activity abnormalities in the pathophysiology of functional dyspepsia (FD). However, whether the functional connectivity between brain regions is changed, especially between the cerebral hemispheres, in patients with FD remains unknown. Thus, the present study aimed to examine the interhemispheric resting‐state functional connectivity (RSFC) changes in patients with FD. Resting‐state functional MRI (fMRI) was performed in 26 patients with FD and in 20 matched healthy controls. An interhemispheric RSFC map was obtained by calculating the Pearson correlation (Fisher Z transformed) between each pair of homotopic voxel time series for each subject. The between‐group difference in interhemispheric RSFC was then examined at global and voxelwise levels separately. The global difference in interhemispheric RSFC between groups was tested using the independent two‐sample t‐test. Voxelwise comparisons were carried out using a permutation‐based nonparametric test, and multiple comparisons across space were corrected using the threshold‐free cluster enhancement (TFCE) method. The results showed that patients with FD had higher global interhemispheric RSFC than healthy controls (p < 0.01). Furthermore, voxelwise analysis revealed that patients with FD had increased interhemispheric RSFC in brain regions including the anterior cingulate cortex, insula and thalamus (p < 0.01, TFCE corrected). Our findings provide preliminary evidence of interhemispheric correlation abnormalities in patients with FD and contribute to a better understanding of the pathophysiology of the disease. Copyright © 2012 John Wiley & Sons, Ltd.     

Sleep patterns and insomnia among adolescents: a population‐based study

The aim of the current study was to examine sleep patterns and rates of insomnia in a population‐based study of adolescents aged 16–19 years. Gender differences in sleep patterns and insomnia, as well as a comparison of insomnia rates according to DSM‐IV, DSM‐V and quantitative criteria for insomnia (Behav. Res. Ther., 41 , 2003, 427), were explored. We used a large population‐based study in Hordaland county in Norway, conducted in 2012. The sample included 10 220 adolescents aged 16–18 years (54% girls). Self‐reported sleep measurements included bedtime, rise time, time in bed, sleep duration, sleep efficiency, sleep onset latency, wake after sleep onset, rate and frequency and duration of difficulties initiating and maintaining sleep and rate and frequency of tiredness and sleepiness. The adolescents reported short sleep duration on weekdays (mean 6:25 hours), resulting in a sleep deficiency of about 2 h. A majority of the adolescents (65%) reported sleep onset latency exceeding 30 min. Girls reported longer sleep onset latency and a higher rate of insomnia than boys, while boys reported later bedtimes and a larger weekday–weekend discrepancy on several sleep parameters. Insomnia prevalence rates ranged from a total prevalence of 23.8 (DSM‐IV criteria), 18.5 (DSM‐V criteria) and 13.6% (quantitative criteria for insomnia). We conclude that short sleep duration, long sleep onset latency and insomnia were prevalent in adolescents. This warrants attention as a public health concern in this age group.     

Negative BOLD during tongue movement: A functional magnetic resonance imaging study

The aim of this functional magnetic resonance imaging (fMRI) study was to evaluate negative blood oxygen level-dependent (BOLD) signals during voluntary tongue movement. Deactivated (Negative BOLD) regions included the posterior parietal cortex (PPC), precuneus, and middle temporal gyrus. Activated (Positive BOLD) regions included the primary somatosensory-motor area (SMI), inferior parietal lobule, medial frontal gyrus, superior temporal gyrus, insula, lentiform nucleus, and thalamus. The results were not consistent with previous studies involving unilateral hand and finger movements showing the deactivation of motor-related cortical areas including the ipsilateral MI. The areas of Negative BOLD in the PPC and precuneus might reflect specific neural networks relating to voluntary tongue movement.     

Saccular stimulation of the human cortex: A functional magnetic resonance imaging study

Recent imaging studies have reported the projection of semicircular canal signals onto wide regions of the cerebral cortex but little is known about otolith projections onto the cerebral cortex. We used functional magnetic resonance imaging (fMRI) to investigate the activation of the cortex by loud clicks that selectively stimulate the sacculus. Twelve normal volunteers were presented with auditory stimuli via an earphone containing a piezo electric element. High-intensity [maximum volume of 120 dB (SPL)] or low-intensity [maximum volume of 110 dB (SPL)] clicks were delivered at a frequency of 1 Hz and lasted 1 ms. We first checked that the high-intensity, but not low-intensity, clicks stimulated the sacculus by determining the vestibular evoked myogenic potentials. We then analyzed two task conditions (high- and low-intensity clicks) in a boxcar paradigm. We obtained gradient echo echo-planar images by using a 1.5 T MRI system. We analyzed the fMRI time series data with SPM2. High-intensity clicks activated wide areas of the cortex, namely, the frontal lobe (prefrontal cortex, premotor cortex, and frontal eye fields), parietal lobe (the region around the intraparietal sulcus, temporo-parietal junction, and paracentral lobule), and cingulate cortex. These areas are similar to those reported in previous imaging studies that analyzed the cortical responses to the activation of the semicircular canals. Thus, semicircular canal and otolith/saccular signals may be processed in similar regions of the human cortex.     

Sleep deprivation compromises resting‐state emotional regulatory processes: An EEG study

Resting‐state spontaneous neural activities consume far more biological energy than stimulus‐induced activities, suggesting their significance. However, existing studies of sleep loss and emotional functioning have focused on how sleep deprivation modulates stimulus‐induced emotional neural activities. The current study aimed to investigate the impacts of sleep deprivation on the brain network of emotional functioning using electroencephalogram during a resting state. Two established resting‐state electroencephalogram indexes (i.e. frontal alpha asymmetry and frontal theta/beta ratio) were used to reflect the functioning of the emotion regulatory neural network. Participants completed an 8‐min resting‐state electroencephalogram recording after a well‐rested night or 24 hr sleep deprivation. The Sleep Deprivation group had a heightened ratio of the power density in theta band to beta band (theta/beta ratio) in the frontal area than the Sleep Control group, suggesting an affective approach with reduced frontal cortical regulation of subcortical drive after sleep deprivation. There was also marginally more left‐lateralized frontal alpha power (left frontal alpha asymmetry) in the Sleep Deprivation group compared with the Sleep Control group. Besides, higher theta/beta ratio and more left alpha lateralization were correlated with higher sleepiness and lower vigilance. The results converged in suggesting compromised emotional regulatory processes during resting state after sleep deprivation. Our work provided the first resting‐state neural evidence for compromised emotional functioning after sleep loss, highlighting the significance of examining resting‐state neural activities within the affective brain network as a default functional mode in investigating the sleep–emotion relationship.     

功能磁共振在大脑皮质发育障碍患者的初步应用研究

目的：应用功能磁共振（fMRI）探讨6名正常受试者及2例皮质发育障碍（DCDs）患者在进行汉语词汇加工过程中脑激活模式，探讨DCDs患者与正常受试者之间脑激活区域的差异与临床意义。方法：本实验采用听觉刺激，以汉语单词理解为语言作业任务。结果：①正常受试者均出现显著的脑区激活，传统语言脑区Wemicke和Broca区激活在双侧大脑半球基本是对称的。除传统语言脑区激活外，还出现其它脑区激活现象。②两例DCDs患者表现为基本语言功能区的激活，诸如Wemicke区和Broca区激活。但脑激活表现为显著的不对称性，甚至完全偏侧性。结论：fMRI能够对大脑DCDs患者功能重塑皮质进行定位，为DCDs伴难治性癫痫患者手术治疗，避免损伤重要功能区提供了有益的保障。     

Sleep and academic performance in later adolescence: results from a large population‐based study

The aim of the current study was to assess the association between sleep duration and sleep patterns and academic performance in 16–19 year‐old adolescents using registry‐based academic grades. A large population‐based study from Norway conducted in 2012, the youth@hordaland‐survey, surveyed 7798 adolescents aged 16–19 years (53.5% girls). The survey was linked with objective outcome data on school performance. Self‐reported sleep measures provided information on sleep duration, sleep efficiency, sleep deficit and bedtime differences between weekday and weekend. School performance [grade point average (GPA)] was obtained from official administrative registries. Most sleep parameters were associated with increased risk for poor school performance. After adjusting for sociodemographic information, short sleep duration and sleep deficit were the sleep measures with the highest odds of poor GPA (lowest quartile). Weekday bedtime was associated significantly with GPA, with adolescents going to bed between 22:00 and 23:00 hours having the best GPA. Also, delayed sleep schedule during weekends was associated with poor academic performance. The associations were somewhat reduced after additional adjustment for non‐attendance at school, but remained significant in the fully adjusted models. In conclusion, the demonstrated relationship between sleep problems and poor academic performance suggests that careful assessment of sleep is warranted when adolescents are underperforming at school. Future studies are needed on the association between impaired sleep in adolescence and later functioning in adulthood.     

Changes in resting connectivity with age: a simultaneous electroencephalogram and functional magnetic resonance imaging investigation

Resting fluctuations in the blood oxygenation level-dependent signal have attracted considerable interest for their sensitivity to pathological brain processes. However, these analyses are susceptible to confound by nonneural physiological factors such as vasculature, breathing, and head movement which is a concern when investigating elderly or pathological groups. Here, we used simultaneous electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) (EEG/fMRI) to constrain the analysis of resting state networks (RSNs) and identify aging differences. Four of 26 RSNs showed fMRI and EEG/fMRI group differences; anterior default-mode network, left frontal-parietal network, bilateral middle frontal, and postcentral gyri. Seven RSNs showed only EEG/fMRI differences suggesting the combination of these 2 methods might be more sensitive to age-related neural changes than fMRI alone. Five RSNs showed only fMRI differences and might reflect nonneural group differences. Activity within some EEG/fMRI RSNs was better explained by neuropsychological measures (Mini Mental State Examination and Stroop) than age. These results support previous studies suggesting that age-related changes in specific RSNs are neural in origin, and show that changes in some RSNs relate better to elderly cognition than age.     

Neural correlates of conceptual object priming in young and older adults: an event-related functional magnetic resonance imaging study

In this event-related functional magnetic resonance imaging study, we investigated age-related differences in brain activity associated with conceptual repetition priming in young and older adults. Participants performed a speeded “living/nonliving” classification task with 3 repetitions of familiar objects. Both young and older adults showed a similar magnitude of behavioral priming to repeated objects and evidenced repetition-related activation reductions in fusiform gyrus, superior occipital, middle, and inferior temporal cortex, and inferior frontal and insula regions. The neural priming effect in young adults was extensive and continued through both the second and third stimulus repetitions, and neural priming in older adults was markedly attenuated and reached floor at the second repetition. In young adults, greater neural priming in multiple brain regions correlated with greater behavioral facilitation and in older adults, only activation reduction in the left inferior frontal correlated with faster behavioral responses. These findings provide evidence for altered neural priming in older adults despite preserved behavioral priming, and suggest the possibility that age-invariant behavioral priming is observed as a result of more sustained neural processing of stimuli in older adults which might be a form of compensatory neural activity.     

Cardiovascular risks and brain function: a functional magnetic resonance imaging study of executive function in older adults

Cardiovascular (CV) risk factors, such as hypertension, diabetes, and hyperlipidemia are associated with cognitive impairment and risk of dementia in older adults. However, the mechanisms linking them are not clear. This study aims to investigate the association between aggregate CV risk, assessed by the Framingham general cardiovascular risk profile, and functional brain activation in a group of community-dwelling older adults. Sixty participants (mean age: 64.6 years) from the Brain Health Study, a nested study of the Baltimore Experience Corps Trial, underwent functional magnetic resonance imaging using the Flanker task. We found that participants with higher CV risk had greater task-related activation in the left inferior parietal region, and this increased activation was associated with poorer task performance. Our results provide insights into the neural systems underlying the relationship between CV risk and executive function. Increased activation of the inferior parietal region may offer a pathway through which CV risk increases risk for cognitive impairment.     

Resting‐state functional connectivity differentiates anxious apprehension and anxious arousal

Brain regions in the default mode network (DMN) display greater functional connectivity at rest or during self‐referential processing than during goal‐directed tasks. The present study assessed resting‐state connectivity as a function of anxious apprehension and anxious arousal, independent of depressive symptoms, in order to understand how these dimensions disrupt cognition. Whole‐brain, seed‐based analyses indicated differences between anxious apprehension and anxious arousal in DMN functional connectivity. Lower connectivity associated with higher anxious apprehension suggests decreased adaptive, inner‐focused thought processes, whereas higher connectivity at higher levels of anxious arousal may reflect elevated monitoring of physiological responses to threat. These findings further the conceptualization of anxious apprehension and anxious arousal as distinct psychological dimensions with distinct neural instantiations.     

Epidemiology of achondroplasia: A population‐based study in Europe

Achondroplasia is a rare genetic disorder resulting in short‐limb skeletal dysplasia. We present the largest European population‐based epidemiological study to date using data provided by the European Surveillance of Congenital Anomalies (EUROCAT) network. All cases of achondroplasia notified to 28 EUROCAT registries (1991–2015) were included in the study. Prevalence, birth outcomes, prenatal diagnosis, associated anomalies, and the impact of paternal and maternal age on de novo achondroplasia were presented. The study population consisted of 434 achondroplasia cases with a prevalence of 3.72 per 100,000 births (95%CIs: 3.14–4.39). There were 350 live births, 82 terminations of pregnancy after prenatal diagnosis, and two fetal deaths. The prenatal detection rate was significantly higher in recent years (71% in 2011–2015 vs. 36% in 1991–1995). Major associated congenital anomalies were present in 10% of cases. About 20% of cases were familial. After adjusting for maternal age, fathers >34 years had a significantly higher risk of having infants with de novo achondroplasia than younger fathers. Prevalence was stable over time, but regional differences were observed. All pregnancy outcomes were included in the prevalence estimate with 80.6% being live born. The study confirmed the increased risk for older fathers of having infants with de novo achondroplasia.     

Sleep stabilizes visuomotor adaptation memory: a functional magnetic resonance imaging study

The beneficial effect of sleep on motor memory consolidation is well known for motor sequence memory, but remains unsettled for visuomotor adaptation in humans. The aim of this study was to characterize more clearly the influence of sleep on consolidation of visuomotor adaptation using a between‐subjects functional magnetic resonance imaging (fMRI) design contrasting sleep to total sleep deprivation. Our behavioural results, based on seven different parameters, show that sleep stabilizes performance whereas sleep deprivation deteriorates it. During training, while a set of cerebellar, striatal and cortical areas is activated in proportion to performance improvement, the recruitment of the hippocampus and frontal cortex protects motor memory against the detrimental effects of sleep deprivation. During retest after sleep loss a cerebello–cortical network, usually involved in the earliest stage of learning, was recruited to perform the task. In contrast, no changes in cerebral activity were observed after sleep, suggesting that it may only support the stabilization of the visuomotor adaptation memory trace.     

特殊感觉障碍人群(盲人)脑功能磁共振成像研究

目的：探讨特殊感觉障碍人群(盲人)大脑枕叶视皮层及相关结构在肓文阅读时充当的角色。方法：采用功能磁共振成像(fMRI)技术研究8名先天和后天盲人，在刺激(触摸中国盲文)和静止等两种对比条件下采集枕叶和有关皮层的回波平面图象。结果：盲人阅读中国盲文时在距状裂附近的纹状区、纹外区包括次级视觉中枢及与视觉信息处理有关的脑区均有激活信号出现，而正常人触摸盲文时上述脑区未出现明显激活信号。结论：枕叶可能参与肓文阅读过程的触觉信息识别：     

A functional magnetic resonance imaging navigated repetitive transcranial magnetic stimulation study of the posterior parietal cortex in normal pain and hyperalgesia

Noxious stimuli activate a complex cerebral network. During central sensitization to pain, activity in most of these areas is changed. One of these areas is the posterior parietal cortex (PPC). The role of the PPC during processing of acute pain as well as hyperalgesia and tactile allodynia remains elusive. Therefore, we performed a functional magnetic resonance imaging (fMRI) based, neuro-navigated, repetitive transcranial magnetic stimulation (rTMS) study in 10 healthy volunteers. Firstly, pin-prick hyperalgesia was provoked on the right volar forearm, using the model of electrically-induced secondary mechanical hyperalgesia. fMRI was performed during pin-prick stimulation inside and outside the hyperalgesic areas. Secondly, on four different experimental sessions, the left and right individual intraparietal BOLD peak-activations were used as targets for a sham-controlled 1 Hz rTMS paradigm of 10 min duration. We measured psychophysically the (i) electrical pain stimulus intensity on an 11-point numeric pain rating scale (NRS, 0–10), the (ii) area of hyperalgesia, and the (iii) area of dynamic mechanical allodynia. Sham stimulation or rTMS was performed 16 min after induction of pin-prick hyperalgesia and tactile allodynia. Compared to sham stimulation, no significant effect of rTMS was observed on pain stimulus intensity and the area of allodynia. However, a reduction of the hyperalgesic area was observed for rTMS of the left PPC (P<0.05). We discuss the role of the PPC in central sensitization to pain, in spatial discrimination of pain stimuli and in spatial-attention to pain stimuli.