GABA concentrations in the human anterior cingulate cortex predict negative BOLD responses in fMRI

The human anterior cingulate cortex (ACC) is part of the default-mode network that shows predominant negative blood oxygen level-dependent (BOLD) responses in functional magnetic resonance imaging (fMRI). We combined fMRI during emotional processing and resting-state magnetic resonance spectroscopy measurements and observed that the concentration of GABA in the ACC specifically correlated with the amount of negative BOLD responses in the very same region. Our findings show that default-mode network negative BOLD responses during emotions are mediated by GABA.     

Evaluation eines internetbasierten E-Learnings für den Studentenunterricht im Fach Augenheilkunde

Background

In 2006, the University Eye Hospital Freiburg (Germany) introduced an Internet-based e-learning module as part of the ophthalmology training for medical students.

Methods

In the e-learning module, the students encounter the same cases as discussed during lectures and seminars. The case presentation is based on an interactive question-and-answer game. Content, format, usability, and effectiveness of the e-learning module were evaluated by the students over two terms.

Results

Of 307 students, 272 used the e-learning module. On average, 94% of the content was processed per student. More than 75% stated that they had fun working with the e-learning module. Students with frequent e-learning use tended to achieve higher marks in their final ophthalmology exams.

Conclusion

E-learning represents a sensible addendum to the established ophthalmology training for medical students. It is comparably easy to integrate into the curriculum and is well accepted by medical students.     

Bariatric Surgery as the One Route to Achieving Donor Heart Transplantation in a Patient with a Left-Ventricular Assist Device

Bariatric and metabolic surgery is currently the most effective procedure of achieving and maintaining weight loss. In the case under discussion, a 48-year-old male patient with heart insufficiency and an implanted left-ventricular assist device (LVAD) wanted to reduce his high BMI (48.6 kg/m²), so as to qualify for the heart transplant waiting list. According to the guidelines, he underwent all the required preoperative testing, which included psychosomatic clarifications, determination of endocrinological causes, and a nutritional consultation. During laparoscopic sleeve gastrectomy, a cardiac technician was present to support the anesthetist. After inserting 3 trocars with no complications, the greater curvature was mobilized using Medtronic''s bipolar electrothermal vessel-sealing instrument, LigaSure™. The resection was performed with an Ethicon™ endostapler. Postoperative monitoring showed no signs of hemorrhage. The patient''s BMI on the day of surgery was 46.8 kg/m² and consecutively fell to 26.7 kg/m² 1 year after the procedure. Follow-up appointments revealed that the patient was fit and in good health. Thus, the patient''s aim of being listed on the transplant list was fulfilled, and at the time of this writing, he is ready to be matched with an organ donor. Because high-BMI patients with inserted LVADs are less likely to receive a donor graft and must remain longer on transplant waiting lists than normal-weight patients, bariatric and metabolic weight loss surgery may lead to a speedier resolution for these high-risk patients.     

Ab interno canaloplasty (ABiC)—12-month results of a new minimally invasive glaucoma surgery (MIGS)

Graefe's Archive for Clinical and Experimental Ophthalmology - The aim of this study is to assess whether the ab interno canaloplasty is a reasonable minimally invasive method to lower...     

Parenteral and enteral nutrition in the management of neurosurgical patients in the intensive care unit

The iatrogenic malnutrition of neurosurgical patients in intensive care units (ICU) is an underestimated problem. It may cause a decrease in plasma albumin and oncotic pressure, leading to an increase in the amount of water entering the brain and increased intracranial pressure (ICP). This study was conducted to test the hypothesis that combined high-protein parenteral and enteral nutrition is beneficial for neurosurgical patients in ICU. A total of 202 neurosurgical patients in ICU (mean age ± standard deviation, 56 years ± 16 years; male:female = 1.2:1) were studied. Two consecutive 1-year time periods were compared, during which two different nutritional regimens were followed. In the first time period (Y1) patients were given a low-protein/high-fat formulation parenterally, followed by a standard enteral regimen. In the second time period (Y2) a protein-rich, combined parenteral and enteral diet was prospectively administered. The Glasgow Outcome Score was measured at 3–6 months after discharge. The following clinical parameters were recorded during the first 2 weeks after admission: ICP; albumin; cholinesterase (CHE); daily hours of ICP > 20 mmHg and cerebral perfusion pressure < 70 mmHg; and Acute Physiology and Chronic Health Evaluation II (APACHE II) score. It was found that overall albumin (32.4 g/L ± 4.1 g/L vs. 27.5 g/L ± 3.6 g/L) and CHE was higher during Y2, although the total energy supply, glucose and fat intake was lower. Higher GOS scores were seen when patients had lower APACHE II scores and received the Y2 nutritional regimen. During Y2, the total hours of ICP > 20 mmHg were fewer. With the Y2 nutrition, maintenance of adequate cerebral perfusion required less catecholamine medication and colloidal fluid replacement. Therefore, adequate nutrition is an important parameter in the management of neurosurgical patients in ICU.     

Sustained cognitive impairments after clinical recovery of severe depression

ABSTRACT: Neuropsychological impairment is prominent in patients with depression, but it is unclear whether deficits persist after clinical response. This study aimed to investigate neuropsychological functions in the course of the illness. Depressive patients were investigated in the acute state and after clinical response using an extensive neuropsychological test battery. After clinical response, there was only a partial improvement in learning and memory and there were no changes regarding working memory, executive functions, and attention. Transient impairments in visual learning and memory suggest a depression-related state effect. The continuing deficits in attention, working memory, and executive function might be considered a trait marker.     

Ketamine administration reduces amygdalo‐hippocampal reactivity to emotional stimulation

Increased amygdala reactivity might lead to negative bias during emotional processing that can be reversed by antidepressant drug treatment. However, little is known on how N‐methyl‐d ‐aspartate (NMDA) receptor antagonism with ketamine as a novel antidepressant drug target might modulate amygdala reactivity to emotional stimulation. Using functional magnetic resonance imaging (fMRI) and resting‐state fMRI (rsfMRI), we assessed amygdalo‐hippocampal reactivity at baseline and during pharmacological stimulation with ketamine (intravenous bolus of 0.12 mg/kg, followed by a continuous infusion of 0.25 mg/kg/h) in 23 healthy subjects that were presented with stimuli from the International Affective Picture System (IAPS). We found that ketamine reduced neural reactivity in the bilateral amygdalo‐hippocampal complex during emotional stimulation. Reduced amygdala reactivity to negative pictures was correlated to resting‐state connectivity to the pregenual anterior cingulate cortex. Interestingly, subjects experienced intensity of psychedelic alterations of consciousness during ketamine infusion predicted the reduction in neural responsivity to negative but not to positive or neutral stimuli. Our findings suggest that the pharmacological modulation of glutamate‐responsive cerebral circuits, which is associated with a shift in emotional bias and a reduction of amygdalo‐hippocampal reactivity to emotional stimuli, represents an early biomechanism to restore parts of the disrupted neurobehavioral homeostasis in MDD patients. Hum Brain Mapp 37:1941–1952, 2016. © 2016 Wiley Periodicals, Inc .     

Segregated neural representation of psychological and somatic-vegetative symptoms in severe major depression

Objective: The Beck Depression Inventory (BDI) is probably the most widely used depression scale. It has been suggested that it contains a two-factor structure measuring cognitive-affective (i.e. psychological) and somatic-vegetative depressive symptoms. In this study we aim to evaluate these factors by probing for their neural correlates. Methods: Neural responses evoked by emotional perception, relative to an emotional judgment task, were measured using functional magnetic resonance imaging (fMRI) in 20 medication-free patients with severe MDD. Psychological and somatic-vegetative symptoms were evaluated with the BDI. Results: Psychological symptoms correlated with signal changes in the dorsomedial and right ventrolateral prefrontal cortex, while somatic-vegetative symptoms correlated with signal changes in the pre-genual anterior cingulate cortex. Conclusions: These preliminary findings demonstrate segregated neural representation of psychological and somatic-vegetative symptoms of MDD in different cortical regions. Thus, our results indicate that the two-factor structure of the BDI is related to distinct neural correlates.     

Anticipating control over aversive stimuli is mediated by the medial prefrontal cortex: An fMRI study with healthy adults

The anticipation of control over aversive events in life is relevant for our mental health. Insights on the underlying neural mechanisms remain limited. We developed a new functional magnetic resonance imaging (fMRI) task that uses auditory stimuli to explore the neural correlates of (1) the anticipation of control over aversion and (2) the processing of aversion. In a sample of 25 healthy adults, we observed increased neural activation in the medial prefrontal cortex (ventromedial prefrontal cortex and rostral anterior cingulate cortex), other brain areas relevant for reward anticipation (ventral striatum, brainstem [ventral tegmental area], midcingulate cortex), and the posterior cingulate cortex when they anticipated control over aversion compared with anticipating no control (1). The processing of aversive sounds compared to neutral sounds (2) was associated with increased neural activation in the bilateral posterior insula. Our findings provide evidence for the important role of medial prefrontal regions in control anticipation and highlight the relevance of conceiving the neural mechanisms involved within a reward‐based framework.