Pupillometry tracks cognitive load and salience network activity in a working memory functional magnetic resonance imaging task

The diameter of the human pupil tracks working memory processing and is associated with activity in the frontoparietal network. At the same time, recent neuroimaging research has linked human pupil fluctuations to activity in the salience network. In this combined functional magnetic resonance imaging (fMRI)/pupillometry study, we recorded the pupil size of healthy human participants while they performed a blockwise organized working memory task (N‐back) inside an MRI scanner in order to monitor the pupil fluctuations associated neural activity during working memory processing. We first confirmed that mean pupil size closely followed working memory load. Combining this with fMRI data, we focused on blood oxygen level dependent (BOLD) correlates of mean pupil size modeled onto the task blocks as a parametric modulation. Interrogating this modulated task regressor, we were able to retrieve the frontoparietal network. Next, to fully exploit the within‐block dynamics, we divided the blocks into 1 s time bins and filled these with corresponding pupil change values (first‐order derivative of pupil size). We found that pupil change within N‐back blocks was positively correlated with BOLD amplitudes in the areas of the salience network (namely bilateral insula, and anterior cingulate cortex). Taken together, fMRI with simultaneous measurement of pupil parameters constitutes a valuable tool to dissect working memory subprocesses related to both working memory load and salience of the presented stimuli.     

End-of-life care for glioma patients; the caregivers’ perspective

Journal of Neuro-Oncology - Gliomas are primary brain tumors with a life-limiting course of disease, and the last weeks of life are often characterized by neurological deficits that affect...     

Ossifying Fibroma of Non-odontogenic Origin: A Fibro-osseous Lesion in the Craniofacial Skeleton to be (Re-)considered

In the cranio-facial skeleton, a heterogeneous group of well characterized fibro-osseous lesions can be distinguished. Whereas fibrous dysplasia can affect any skeletal bone, ossifying fibroma and cemento-osseous dysplasia exclusively develop in the cranio-facial region, with most subtypes restricted to the tooth bearing areas of the jaws. Herein we present a series of 20 fibro-osseous lesions that developed mostly in the frontal bone and in the mandible, presenting as expansile intramedullary tumors with a unique histologic appearance and an indolent clinical course. We provide evidence that these tumors are distinct from the categories included in the WHO classification and are therefore currently unclassifiable. The definition of cemento-ossifying fibroma as an odontogenic neoplasm developing only in close proximity to teeth should be re-considered and incorporate also extragnathic lesions as shown here.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12105-021-01351-3.     

Short-term benefit of smoking cessation in patients with coronary heart disease: estimates based on self-reported smoking data and serum cotinine measurements.

AIMS: To assess the short-term impact of smoking and smoking cessation measured by self-report and by serum cotinine on the risk of secondary cardiovascular disease events (CVD events). METHODS AND RESULTS: Cohort study among participants of an in-patient 3-week rehabilitation programme following an acute coronary syndrome or coronary artery revascularization. Smoking status at baseline was assessed by self-report (beginning of the rehabilitation programme, rehab) and serum cotinine (end of rehab). Active follow-up was conducted one year later. Subsequent CVD events were observed in 139 of the 967 patients. Both self-reported smoking status (odds ratio (OR) compared to continued smokers: recent quitters 0.96, former smokers 0.83, never smokers 0.54, p for trend 0.04) and serum cotinine (OR 0.59 (95% confidence interval (CI) 0.36-0.97) for cotinine-negative compared to cotinine-positive subjects) were associated with the occurrence of a secondary CVD event. After reclassification of all cotinine-positive subjects to continued smokers and cotinine-negative self-reported smokers to recent quitters, this association became even stronger. The OR now reached 0.71 (95% CI interval 0.38-1.33) for recent quitters, 0.64 (0.36-1.11) for former smokers and 0.44 (0.24-0.81) for never smokers (p-value for trend=0.009). CONCLUSION: The benefits of non-smoking and smoking cessation in cardiac patients are beyond controversy and might even be larger than suggested by previous studies which exclusively relied on self-reported smoking status.     

Cranioplasty after decompressive hemicraniectomy: Underestimated surgery-associated complications?

Objective

Decompressive hemicraniectomy (DC) and duroplasty after malignant brain infarction or traumatic brain injury is a common surgical procedure. Usually, preserved bone flaps are being reimplanted after resolution of brain swelling. Alloplast cranioplasties are seldom directly implanted due to the risk of wound healing disorders. While numerous studies deal with DC, little is known about the encountered problems of bone flap reimplantation. Thus, aim of the study was to identify surgery-associated complications after bone flap reimplantation.

Methods

We performed a retrospective chart analysis of patients that underwent DC and subsequent bone flap reimplantation between 2001 and 2011 at our institution. We registered demographic data, initial clinical diagnosis and surgery-associated complications.

Results

We identified 136 patients that underwent DC and subsequent reimplantation. Forty-one patients (30.1%) had early or late surgery-associated complications after bone flap reimplantation. Most often, bone flap resorption and postoperative wound infections were the underlying causes (73%, n = 30/41). Multivariate analysis identified age (p = 0.045; OR = 16.30), GOS prior to cranioplasty (p = 0.03; OR = 2.38) and nicotine abuse as a prognostic factor for surgery-associated complications (p = 0.043; OR = 4.02). Furthermore, patients with early cranioplasty had a better functional outcome than patients with late cranioplasty (p < 0.05).

Conclusions

Almost one-third of the patients that are operated on for bone flap reimplantation after DC suffer from surgery-associated complications. Most often, wound healing disorders as well as bone flap resorption lead to a second or even third operation with the need for artificial bone implantation. These results might raise the question, if subsequent operations can be avoided, if an artificial bone is initially chosen for cranioplasty.     

Mice with reduced brain-derived neurotrophic factor expression show decreased choline acetyltransferase activity, but regular brain monoamine levels and unaltered emotional behavior

The "neurotrophin hypothesis" of depression predicts that depressive disorders in humans coincide with a decreased activity and/or expression of brain-derived neurotrophic factor (BDNF) in the brain. Therefore, we investigated whether mice with a reduced BDNF expression due to heterozygous gene disruption demonstrate depression-like neurochemical changes or behavioral symptoms. BNDF protein levels of adult BDNF(+/-) mice were reduced to about 60% in several brain areas investigated, including the hippocampus, frontal cortex, striatum, and hypothalamus. The content of monoamines (serotonin, norepinephrine, and dopamine) as well as of serotonin and dopamine degradation products was unchanged in these brain regions. By contrast, choline acetyltransferase activity was significantly reduced by 19% in the hippocampus of BDNF(+/-) mice, indicating that the cholinergic system of the basal forebrain is critically dependent on sufficient endogenous BDNF levels in adulthood. Moreover, BDNF(+/-) mice exhibited normal corticosterone and adrenocorticotropic hormone (ACTH) serum levels under baseline conditions and following immobilization stress. In a panel of behavioral tests investigating locomotor activity, exploration, anxiety, fear-associated learning, and behavioral despair, BDNF(+/-) mice were indistinguishable from wild-type littermates. Thus, a chronic reduction of BDNF protein content in adult mice is not sufficient to induce neurochemical or behavioral alterations that are reminiscent of depressive symptoms in humans.