Primary motor cortex activation and lateralization in patients with tumors of the central region

AbstractHemispheric lateralization is a frequently encountered phenomenon of cortical function. It describes the functional specialization of a region on one side of the brain for a given task. It is well characterized in motor and sensory, as well as language systems and becomes more and more known for various cognitive domains. While in the adult healthy brain hemispheric lateralization is mostly set, pathological processes may lead to cortical reorganization. In these cases neuroplasticity of the corresponding region in the non-dominant hemisphere seems to play an important role. In a previous study we investigated language associated regions in right-handed patients with frontal and temporal tumors of the left hemisphere. We observed a marked change of language lateralization in these patients towards the non-dominant hemisphere as measured by functional MRI (Partovi et al., 2012).In the present study we evaluated activation and lateralization of cortical motor areas in patients with tumors of the central region. BOLD fMRI was performed during unilateral voluntary movements of the contralesional hand in 87 patients. Individual correlations of measured BOLD-signals with the model hemodynamic reference function were determined on a ROI basis in single subjects and compared to those of 16 healthy volunteers. In volunteers the strongest activation is usually found in the M1 hand representation contralateral to the movement, while a weaker homotopic co-activation is observed in ipsilateral M1 (Stippich et al., 2007a). In the patient group our results show significant changes of motor activations, ranging from a reduction of M1 lateralization to equalization of M1 activations or even inversion of M1 lateralization during contralesional movements. This study corroborates in a large patient group the idea that lesions affecting M1 may lead to functional reorganization of cortical motor systems and in particular equalize hemispheric lateralization. However, it is not yet clear whether these changes are only an epiphenomenon or indeed reflect an attempt of recovery of brain function

Increased Volume and Function of Right Auditory Cortex as a Marker for Absolute Pitch

Absolute pitch (AP) perception is the auditory ability to effortlessly recognize the pitch of any given tone without external reference. To study the neural substrates of this rare phenomenon, we developed a novel behavioral test, which excludes memory-based interval recognition and permits quantification of AP proficiency independently of relative pitch cues. AP- and non-AP-possessing musicians were studied with morphological and functional magnetic resonance imaging (fMRI) and magnetoencephalography. Gray matter volume of the right Heschl's gyrus (HG) was highly correlated with AP proficiency. Right-hemispheric auditory evoked fields were increased in the AP group. fMRI revealed an AP-dependent network of right planum temporale, secondary somatosensory, and premotor cortices, as well as left-hemispheric "Broca's” area. We propose the right HG as an anatomical marker of AP and suggest that a right-hemispheric network mediates AP "perception,” whereas pitch "labeling” takes place in the left hemispher

The Bright, Artificial Intelligence-Augmented Future of Neuroimaging Reading

Radiologists are among the first physicians to be directly affected by advances in computer technology. Computers are already capable of analyzing medical imaging data, and with decades worth of digital information available for training, will an artificial intelligence (AI) one day signal the end of the human radiologist? With the ever increasing work load combined with the looming doctor shortage, radiologists will be pushed far beyond their current estimated 3 s allotted time-of-analysis per image; an AI with super-human capabilities might seem like a logical replacement. We feel, however, that AI will lead to an augmentation rather than a replacement of the radiologist. The AI will be relied upon to handle the tedious, time-consuming tasks of detecting and segmenting outliers while possibly generating new, unanticipated results that can then be used as sources of medical discovery. This will affect not only radiologists but all physicians and also researchers dealing with medical imaging. Therefore, we must embrace future technology and collaborate interdisciplinary to spearhead the next revolution in medicine

Leftward Lateralization of Auditory Cortex Underlies Holistic Sound Perception in Williams Syndrome

BACKGROUND: Individuals with the rare genetic disorder Williams-Beuren syndrome (WS) are known for their characteristic auditory phenotype including strong affinity to music and sounds. In this work we attempted to pinpoint a neural substrate for the characteristic musicality in WS individuals by studying the structure-function relationship of their auditory cortex. Since WS subjects had only minor musical training due to psychomotor constraints we hypothesized that any changes compared to the control group would reflect the contribution of genetic factors to auditory processing and musicality. METHODOLOGY/PRINCIPAL FINDINGS: Using psychoacoustics, magnetoencephalography and magnetic resonance imaging, we show that WS individuals exhibit extreme and almost exclusive holistic sound perception, which stands in marked contrast to the even distribution of this trait in the general population. Functionally, this was reflected by increased amplitudes of left auditory evoked fields. On the structural level, volume of the left auditory cortex was 2.2-fold increased in WS subjects as compared to control subjects. Equivalent volumes of the auditory cortex have been previously reported for professional musicians. CONCLUSIONS/SIGNIFICANCE: There has been an ongoing debate in the neuroscience community as to whether increased gray matter of the auditory cortex in musicians is attributable to the amount of training or innate disposition. In this study musical education of WS subjects was negligible and control subjects were carefully matched for this parameter. Therefore our results not only unravel the neural substrate for this particular auditory phenotype, but in addition propose WS as a unique genetic model for training-independent auditory system properties

Does local cerebellar volume predict treatment success in anorexia nervosa?

Anorexia nervosa (AN) is difficult to treat with up to half of patients failing to gain weight during treatment. Neurobiological factors predicting treatment response in AN are poorly understood. In this longitudinal study, we aimed to identify morphological characteristics in the grey matter which predict treatment success in patients with AN. Fifty patients with severe AN participated in an eating disorder-specific inpatient treatment. On admission, T1-weighted magnetic resonance images were acquired from all patients. Half of the patients successfully gained weight, reaching a body-mass index ≥ 17.5 kg/m2. Using voxel-based morphometry, local grey matter volumes were compared between the two groups of patients who gained weight and those who did not. This approach allowed us to identify anatomical characteristics which predict treatment success in terms of post-treatment weight status. Patients who did not reach the weight threshold at discharge had a smaller volume in the right cerebellar crus I at the time of admission. In this group, smaller volume was associated with a greater alexithymia score. The findings suggest that a trophic state within the cerebellum before treatment might be prognostic for treatment success. Consistent with previous reports, this result further substantiates the possible role of the cerebellum in the psychopathology of AN

Thérapie cellulaire du diabète (influence des caractéristiques du donneur et du prélèvement pancréatique sur l'isolement des îlots de Langerhans)

Depuis les résultats de l'équipe d'Edmonton publiés en 2000, la greffe d'îlots de Langerhans connaît un essor particulier avec plus de 500 patients diabétiques traités par cette thérapeutique dans le monde. Malgré ces progrès réels, les freins demeurent la nécessité d'un traitement immunosuppresseur prolongé, la rareté des pancréas disponibles et le caractère imprévisible des résultats de l'isolement des îlots. Après un bref rappel et un historique de la greffe d'îlots de Langerhans, nous avons présenté les techniques actuelles du prélèvement pancréatique ainsi que les résultats de l'isolement des îlots dans notre équipe. Nous avons ensuite montré l'influence de la nature du liquide de conservation sur les résultats de l'isolement. Nous avons également démontré chez le Porc le caractère prédictif de la masse endocrine évaluée in vivo chez le donneur sur le rendement de l'isolement. Dans un second temps, ces résultats ont été confirmés chez l'Homme et ont permis d'envisager une sélection rationnelle des donneurs en vue de l'isolement d'îlots.Since the publication of clinical results in 2000 by the Edmonton team, islet transplantation has been on the rise where more than 500 diabetic patients have received this new therapy around the world. Despite this real progress, drawbacks remain such as the use of a prolonged immunosuppressive regimen, scarce organ availability for isolation and the unpredictable nature of isolation methods. Following a brief historical overview of the islet transplantation, we presented the current techniques of pancreas procurement and our islet isolation results. We then showed the influence of the conservation solution on the results of islet isolation. We were also able to establish in the pig model the predictive value of the pancreatic endocrine mass assessed in vivo in the donor on the isolation outcome. Secondly, we confirmed these results in man allowing us to consider a rational selection of donors prior to islet isolation.LILLE2-BU Santé-Recherche (593502101) / SudocPARIS-Académie Médecine (751065201) / SudocSudocFranceF

Increased gray matter volume of the auditory cortex and higher incidence of posterior duplications in WS subjects.

<p>(<b>a</b>) Averaged individual AC landmarks and MEG dipoles (filled circles) (<b>b</b>) Probability maps of HG including local duplications anterior to the first complete Heschl's sulcus. The number of overlapping voxels is color coded, <i>i.e.</i> red means that >80% of the brains overlapped in this voxel. (<b>a,b</b>) Plots in xy-Talairach (TAL) stereotaxic coordinates. (<b>c</b>) Morphometry of whole brain (B, light grey), grey matter (GM, medium grey), left HG (blue) and right HG (red) before and after normalization. ACPC =  plane of anterior and posterior commissure; a =  anterior; p =  posterior; r =  right; l =  left; aSTG =  anterior supratemporal gyrus; HG =  Heschl's Gyrus; D =  complete posterior HG duplication; PT =  planum temporale; B =  total brain volume; GM =  gray matter.</p

Demographic and psychoacoustic data.

<p>Sound perception: Index δ =  (<i>SP</i> - <i>H</i>)/(<i>SP</i>+<i>H</i>) according to the number of perceived holistic (<i>H</i>) and spectral (<i>SP</i>) items of the sound perception test <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0012326#pone.0012326-Schneider1" target="_blank">[1]</a>. Age (years), musical expertise (hours of training per day) and sound perception index (δ) are presented as mean ± standard error (s.e.m.). ANOVA: <i>p-</i>value of WS vs. control group of spectral listeners (C<i>_SP</i>) and WS vs. control group of holistic listeners (C<i>_H</i>).</p

MEG source activity.

<p>Source activity: Dipole amplitudes of auditory evoked P50responses (nAm). Dipole localization: normalized y-coordinate in anterior-posterior direction (mm). ANOVA: <i>p-</i>value of WS vs. spectral listeners of control group (C<i>_SP</i>) and WS vs. holistic listeners of control group (C<i>_H</i>).</p