Acute hyperglycemia and spatial working memory in adolescents with type 1 diabetes

<i>Objective:</i> <a>To investigate the effect of acute hyperglycemia on brain function in adolescents with type 1 diabetes.</a> <p><i><br></i></p><p><i>Research Design and Methods:</i><b> </b>Twenty participants with type 1 diabetes (T1D) (age 14.64 ±1.78 years) and 20 age-matched healthy controls (age 14.40± 2.82 years) performed two functional magnetic resonance imaging sessions. Participants with T1D performed the first scanning session under euglycemic and the second under hyperglycemic clamp (20 mmol/L (360 mg/dL)).<b> </b></p> <p><i><br></i></p><p><i>Results:</i> Lower spatial working memory (sWM) capacity during acute hyperglycemia and significant differences in activation of regions of interest during different stages of the spatial working memory task (p=0.014) were observed.<b> </b><b></b></p> <p><i><br></i></p><p><i>Conclusions</i>: Acute hyperglycemia negatively affected sWM capacity in adolescents with T1D, which is relevant for daily functioning and academic performance.</p>

Acute hyperglycemia and spatial working memory in adolescents with type 1 diabetes

<i>Objective:</i> <a>To investigate the effect of acute hyperglycemia on brain function in adolescents with type 1 diabetes.</a> <p><i><br></i></p><p><i>Research Design and Methods:</i><b> </b>Twenty participants with type 1 diabetes (T1D) (age 14.64 ±1.78 years) and 20 age-matched healthy controls (age 14.40± 2.82 years) performed two functional magnetic resonance imaging sessions. Participants with T1D performed the first scanning session under euglycemic and the second under hyperglycemic clamp (20 mmol/L (360 mg/dL)).<b> </b></p> <p><i><br></i></p><p><i>Results:</i> Lower spatial working memory (sWM) capacity during acute hyperglycemia and significant differences in activation of regions of interest during different stages of the spatial working memory task (p=0.014) were observed.<b> </b><b></b></p> <p><i><br></i></p><p><i>Conclusions</i>: Acute hyperglycemia negatively affected sWM capacity in adolescents with T1D, which is relevant for daily functioning and academic performance.</p>

A functional connectome phenotyping dataset including cognitive state and personality measures

The dataset enables exploration of higher-order cognitive faculties, self-generated mental experience, and personality features in relation to the intrinsic functional architecture of the brain. We provide multimodal magnetic resonance imaging (MRI) data and a broad set of state and trait phenotypic assessments: mind-wandering, personality traits, and cognitive abilities. Specifically, 194 healthy participants (between 20 and 75 years of age) filled out 31 questionnaires, performed 7 tasks, and reported 4 probes of in-scanner mind-wandering. The scanning session included four 15.5-min resting-state functional MRI runs using a multiband EPI sequence and a high-resolution structural scan using a 3D MP2RAGE sequence. This dataset constitutes one part of the MPI-Leipzig Mind-Brain-Body database.

Extracting Cross-Sectional Clinical Images Based on Their Principal Axes of Inertia

Cross-sectional imaging is considered the gold standard in diagnosing a range of diseases. However, despite its widespread use in clinical practice and research, no widely accepted method is available to reliably match cross-sectional planes in several consecutive scans. This deficiency can impede comparison between cross-sectional images and ultimately lead to misdiagnosis. Here, we propose and demonstrate a method for finding the same imaging plane in images obtained during separate scanning sessions. Our method is based on the reconstruction of a “virtual organ” from which arbitrary cross-sectional images can be extracted, independent of the axis orientation in the original scan or cut; the key is to establish unique body coordinates of the organ from its principal axes of inertia. To verify our method a series of tests were performed, and the same cross-sectional plane was successfully extracted. This new approach offers clinicians access, after just a single scanning session, to the morphology and structure of a lesion through cross-sectional images reconstructed along arbitrary axes. It also aids comparable detection of morphological and structural changes in the same imaging plane from scans of the same patient taken at different times—thus potentially reducing the misdiagnosis rate when cross-sectional images are interpreted.

Spatial Cognition and the Hippocampus: The Anterior–Posterior Axis

We discuss the question of differentiation along the anterior–posterior longitudinal axis of the hippocampus. Data from a recent fMRI study are reanalyzed to determine whether activations in these hippocampal regions are affected by the nature of the information being accessed during a scanning session in which participants thought about episodes from their lives. Retrieving detailed spatial relational information preferentially activated the posterior hippocampus, whereas retrieving information about locales (or contexts) preferentially activated the anterior hippocampus. These data support the view that there is functional differentiation along the longitudinal axis in humans that matches what has been seen in rats, namely, that the posterior (dorsal) hippocampus is crucial for precise spatial behavior, and the anterior (ventral) hippocampus is crucial for context coding.

The effects of rehearsal on auditory cortex: An fMRI study of the putative neural mechanisms of dance therapy

We were interested in examining the time course of the evolution when beginning to learn a motor habit and it’s associated neural functional changes in the brain. To accomplish this we employed five professional dancers that were scanned using a within subjects design. Each dancer participated in four fMRI (functional magnetic resonance imaging) scanning sessions over the training and learning of a dance to a 1 min piece of music employing a typical blocked design (5 epochs with alternations of a 30-s fixation period). We also tested five control subjects that had dance experience but did not learn the dance to this music. Subjects were asked to visualize dancing while listening to a piece of music. At the first scanning session, only 4 rehearsals of the piece (initial acquisition phase) were studied. The control subjects were also tested at this time period but they had no rehearsals and had no visual exposure to the music before scanning. The second scanning session occurred one week later, after a total of 9 rehearsals. The third scanning session was completed 7 weeks after initial acquisition of the dance (the dance was performed a total of 16 times after initial training). Thus in total there were 22 scanning sessions using 10 subjects. Additionally a control motor scan was performed in each scanning session to activate motor regions that should not change activation patterns across all scanning sessions. Results revealed a significant increase of BOLD signal, across the sessions in a network of brain regions including bilateral auditory cortex to supplementary motor cortex. These results suggest that as we learn a motor sequence from music, greater neuronal activity occurs and we discuss the potential neural network involved in dance and its implications towards alternative neural regions that are potentially recruited during dance therapy.

Progesterone and Cerebral Function during Emotion Processing in Men and Women with Schizophrenia

Schizophrenia has been associated with disturbed levels of sex-steroid hormones, including estrogen and testosterone. In the present study we have examined the implication of a less studied hormone progesterone. Forty-three patients with schizophrenia (21 women) and 43 control participants (21 women) underwent functional MRI while viewing emotionally positive, negative, and neutral images. Blood samples were taken prior to the scanning session to evaluate progesterone levels. Simple regression analyses between levels of progesterone and brain activations associated with emotion processing were performed using SPM5. A positive correlation was found between progesterone levels and brain activations during processing of emotionally charged images in both healthy and schizophrenia men, but no significant relationship was revealed in women. These preliminary results indicate that progesterone is significantly associated with brain activations during processing of positive and negative affect in healthy and schizophrenia men, but not in women. Further investigation is warranted.

Neural Decoding with Hierarchical Generative Models

Recent research has shown that reconstruction of perceived images based on hemodynamic response as measured with functional magnetic resonance imaging (fMRI) is starting to become feasible. In this letter, we explore reconstruction based on a learned hierarchy of features by employing a hierarchical generative model that consists of conditional restricted Boltzmann machines. In an unsupervised phase, we learn a hierarchy of features from data, and in a supervised phase, we learn how brain activity predicts the states of those features. Reconstruction is achieved by sampling from the model, conditioned on brain activity. We show that by using the hierarchical generative model, we can obtain good-quality reconstructions of visual images of handwritten digits presented during an fMRI scanning session.

Distinct Effects of D9-tetrahydrocannabinol and Cannabidiol on Neural Activation During Emotional Processing

Aims:Cannabis use can both increase and reduce anxiety in humans. The neurophysiological substrates of these effects are unknown.Method:Fifteen healthy English-native right-handed men were studied on three separate occasions using an event-related fMRI paradigm while viewing faces that implicitly elicited different levels of anxiety. Each scanning session was preceded by the ingestion of either 10mg of D-9-THC, 600mg of CBD, or a placebo, in a double-blind, randomised, placebo controlled design. Electrodermal activity (Skin Conductance Response, SCR) and objective and subjective ratings of anxiety were recorded durign the scanning.Results:D-9THC increased anxiety, as well as levels of intoxication, sedation and psychotic symptoms, whereas there was a trend for a reduction in anxiety following administration of CBD. The number of SCR fluctuations during the processing of intensely fearful faces increased following administration of D-9THC but decreased following administration of CBD. CBD attenuated the BOLD signal in the amygdala and the anterior and posterior cingulate cortex while subjects were processing intensely fearful faces, and its suppression of the amygdalar and posterior cingulate responses was correlated with the concurrent reduction in SCR fluctuations. D-9-THC mainly modulated activation in frontal and parietal areas.Conclusions:D-9-THC and CBD had clearly distinct effects on the neural, eclectrodermal and symptomatic response to fearful faces. The effects of CBD on activation in limbic and paralimbic regions may contribute to its ability to reduce autonomic arousal and subjective anxiety, whereas the anxiogenic effects of D-9-THC may be related to effects in other brain regions.

Sources of variation influencing the use of real-time ultrasound to predict intramuscular fat in live beef cattle

A total of 123 steers of six European breeds (Angus, Simmental, Charolais, Limousin, Blonde d'Aquitaine, Piedmontese) were used (i) to evaluate the precision of the ultrasound-predicted intramuscular fat (USIMF) and its sources of variation using the current Pie QUIP technology and (ii) to develop improved models for predicting USIMF. Steers were slaughtered when they reached the target value of 3.5% USIMF. Hide samples were obtained 3 d before slaughter by shot-biopsy. After slaughter, a sample of the longissimus muscle was used to determine actual chemical intramuscular fat (EEIMF), collagen content and solubility. Among the variables available during a chute-side scanning session, hide thickness and ultrasound subcutaneous fat thickness at the 12th and 13th ribs were shown to be significantly correlated with EEIMF. These two variables were selected as possible independent variables to evaluate the construction of new models. The model with the best fit included USIMF, hide thickness and liveweight and had a standard error of prediction of 0.96%, which is similar to other published technologies. Breed group and collagen-related traits did not influence USIMF estimation. Finally, the revised Pie QUIP technology should be considered as one technology of choice to predict EEIMFcontent in live animals. Key words: Beef, cattle, ultrasound, intramuscular fat, hide thickness, collagen