Medial Orbitofrontal Regions Research Articles

The "limbic network," comprising orbitofrontal and anterior temporal cortex, is part of an extended default network: Evidence from multi-echo fMRI.

Resting-state functional magnetic resonance imaging (fMRI) investigations have provided a view of the default network (DN) as composed of a specific set of frontal, parietal, and temporal cortical regions. This spatial topography is typically defined with reference to an influential network parcellation scheme that designated the DN as one of seven large-scale networks (Yeo et al., 2011). However, the precise functional organization of the DN is still under debate, with studies arguing for varying subnetwork configurations and the inclusion of subcortical regions. In this vein, the so-called limbic network-defined as a distinct large-scale network comprising the bilateral temporal poles, ventral anterior temporal lobes, and orbitofrontal cortex-is of particular interest. A large multi-modal and multi-species literature on the anatomical, functional, and cognitive properties of these regions suggests a close relationship to the DN. Notably, these regions have poor signal quality with conventional fMRI acquisition, likely obscuring their network affiliation in most studies. Here, we leverage a multi-echo fMRI dataset with high temporal signal-to-noise and whole-brain coverage, including orbitofrontal and anterior temporal regions, to examine the large-scale network resting-state functional connectivity of these regions and assess their associations with the DN. Consistent with our hypotheses, our results support the inclusion of the majority of the orbitofrontal and anterior temporal cortex as part of the DN and reveal significant heterogeneity in their functional connectivity. We observed that left-lateralized regions within the temporal poles and ventral anterior temporal lobes, as well as medial orbitofrontal regions, exhibited the greatest resting-state functional connectivity with the DN, with heterogeneity across DN subnetworks. Overall, our findings suggest that, rather than being a functionally distinct network, the orbitofrontal and anterior temporal regions comprise part of a larger, extended default network.

Multimodal neuroimaging exploration of the mechanisms of sleep quality deterioration after SARS-CoV-2 Omicron infection

BackgroundTo evaluate the neurological alterations induced by Omicron infection, to compare brain changes in chronic insomnia with those in exacerbated chronic insomnia in Omicron patients, and to examine individuals without insomnia alongside those with new-onset insomnia.MethodsIn this study, a total of 135 participants were recruited between January 11 and May 4, 2023, including 26 patients with chronic insomnia without exacerbation, 24 patients with chronic insomnia with exacerbation, 40 patients with no sleep disorder, and 30 patients with new-onset insomnia after infection with Omicron (a total of 120 participants with different sleep statuses after infection), as well as 15 healthy controls who were never infected with Omicron. Neuropsychiatric data, clinical symptoms, and multimodal magnetic resonance imaging data were collected. The gray matter thickness and T1, T2, proton density, and perivascular space values were analyzed. Associations between changes in multimodal magnetic resonance imaging findings and neuropsychiatric data were evaluated with correlation analyses.ResultsCompared with healthy controls, gray matter thickness changes were similar in the patients who have and do not have a history of chronic insomnia groups after infection, including an increase in cortical thickness near the parietal lobe and a reduction in cortical thickness in the frontal, occipital, and medial brain regions. Analyses showed a reduced gray matter thickness in patients with chronic insomnia compared with those with an aggravation of chronic insomnia post-Omicron infection, and a reduction was found in the right medial orbitofrontal region (mean [SD], 2.38 [0.17] vs. 2.67 [0.29] mm; P < 0.001). In the subgroups of Omicron patients experiencing sleep deterioration, patients with a history of chronic insomnia whose insomnia symptoms worsened after infection displayed heightened medial orbitofrontal cortical thickness and increased proton density values in various brain regions. Conversely, patients with good sleep quality who experienced a new onset of insomnia after infection exhibited reduced cortical thickness in pericalcarine regions and decreased proton density values. In new-onset insomnia patients post-Omicron infection, the thickness in the right pericalcarine was negatively correlated with the Self-rating Anxiety Scale (r = − 0.538, P = 0.002, PFDR = 0.004) and Self-rating Depression Scale (r = − 0.406, P = 0.026, PFDR = 0.026) scores.ConclusionsThese findings help us understand the pathophysiological mechanisms involved when Omicron invades the nervous system and induces various forms of insomnia after infection. In the future, we will continue to pay attention to the dynamic changes in the brain related to insomnia caused by Omicron infection.

The relevance of Spearman's g for epilepsy.

Whilst the concept of a general mental factor known as 'g' has been of longstanding interest, for unknown reasons, it has never been interrogated in epilepsy despite the 100+ year empirical history of the neuropsychology of epilepsy. This investigation seeks to identify g within a comprehensive neuropsychological data set and compare participants with temporal lobe epilepsy to controls, characterize the discriminatory power of g compared with domain-specific cognitive metrics, explore the association of g with clinical epilepsy and sociodemographic variables and identify the structural and network properties associated with g in epilepsy. Participants included 110 temporal lobe epilepsy patients and 79 healthy controls between the ages of 19 and 60. Participants underwent neuropsychological assessment, clinical interview and structural and functional imaging. Cognitive data were subjected to factor analysis to identify g and compare the group of patients with control participants. The relative power of g compared with domain-specific tests was interrogated, clinical and sociodemographic variables were examined for their relationship with g, and structural and functional images were assessed using traditional regional volumetrics, cortical surface features and network analytics. Findings indicate (i) significantly (P < 0.005) lower g in patients compared with controls; (ii) g is at least as powerful as individual cognitive domain-specific metrics and other analytic approaches to discriminating patients from control participants; (iii) lower g was associated with earlier age of onset and medication use, greater number of antiseizure medications and longer epilepsy duration (Ps < 0.04); and lower parental and personal education and greater neighbourhood deprivation (Ps < 0.012); and (iv) amongst patients, lower g was linked to decreased total intracranial volume (P = 0.019), age and intracranial volume adjusted total tissue volume (P = 0.019) and age and intracranial volume adjusted total corpus callosum volume (P = 0.012)-particularly posterior, mid-posterior and anterior (Ps < 0.022) regions. Cortical vertex analyses showed lower g to be associated specifically with decreased gyrification in bilateral medial orbitofrontal regions. Network analysis of resting-state data with focus on the participation coefficient showed g to be associated with the superior parietal network. Spearman's g is reduced in patients, has considerable discriminatory power compared with domain-specific metrics and is linked to a multiplex of factors related to brain (size, connectivity and frontoparietal networks), environment (familial and personal education and neighbourhood disadvantage) and disease (epilepsy onset, treatment and duration). Greater attention to contemporary models of human cognition is warranted in order to advance the neuropsychology of epilepsy.

Frequency Dependent Changes of Regional Homogeneity in Children with Growth Hormone Deficiency.

Abnormal spontaneous neural activity in children with growth hormone deficiency (GHD) has been found in previous resting-state functional magnetic resonance imaging (rs-fMRI) studies. Nevertheless, the spontaneous neural activity of GHD in different frequency bands is still unclear. Here, we combined rs-fMRI and regional homogeneity (ReHo) methods to analyze the spontaneous neural activity of 26 GHD children and 15 healthy controls (HCs) with age- and sex-matching in four frequency bands: slow-5 (0.014-0.031Hz), slow-4 (0.031-0.081Hz), slow-3 (0.081-0.224Hz), and slow-2 (0.224-0.25Hz). In the slow-5 band, GHD children compared with HCs displayed higher ReHo in the left dorsolateral part of the superior frontal gyrus, triangular part of the inferior frontal gyrus, precentral gyrus and middle frontal gyrus, and right angular gyrus, while lower ReHo in the right precentral gyrus, and several medial orbitofrontal regions. In the slow-4 band, GHD children relative to HCs revealed increased ReHo in the right middle temporal gyrus, whereas reduced ReHo in the left superior parietal gyrus, right middle occipital gyrus, and bilateral medial parts of the superior frontal gyrus. In the slow-2 band, compared with HCs, GHD children showed increased ReHo in the right anterior cingulate gyrus, and several prefrontal regions, while decreased ReHo in the left middle occipital gyrus, and right fusiform gyrus and anterior cingulate gyrus. Our findings demonstrate that regional brain activity in GHD children exhibits extensive abnormalities, and these abnormalities are related to specific frequency bands, which may provide bases for understanding its pathophysiology significance.

Posterior-prefrontal and medial orbitofrontal regions play crucial roles in happiness and sadness recognition

The core brain regions responsible for basic human emotions are not yet fully understood. We investigated the key areas responsible for emotion recognition of facial expressions of happiness and sadness using data obtained from patients who underwent local brain resection. A total of 44 patients with right cerebral hemispheric brain tumors and 33 healthy volunteers were enrolled and subjected to a facial expression recognition test. Voxel-based lesion-symptom mapping was performed to investigate the relationship between the accuracy of emotion recognition and the resected regions. Consequently, trade-off relationships were discovered: the posterior-prefrontal region was related to a low score of happiness recognition and a high score of sadness recognition (disorder-of-happiness group), whereas the medial orbitofrontal region was related to a low score of sadness recognition and a high score of happiness recognition (disorder-of-sadness group). The emotion recognition score in both the happiness and sadness disorder groups was significantly lower than that in the control group (p = 0.0009 and p = 0.021, respectively). Interestingly, the deficit in happiness recognition was temporary, whereas the deficit in sadness recognition persisted during the chronic phase. Using graph theoretical analysis, we identified structural connectivity between the posterior-prefrontal and medial orbitofrontal regions. When either of these regions was damaged, the tract volume connecting them was significantly reduced (p = 0.013). These results indicate that the posterior-prefrontal and medial orbitofrontal regions may be crucial for maintaining a balance between happiness and sadness recognition in humans. Investigating the clinical impact of certain area resections using lesion studies combined with connectivity analysis is a useful neuroimaging method for understanding neural networks.

Volumetric Alterations of the Cerebral Cortex in Eating Disorders.

Eating disorders are relatively frequent psychiatric disorders that can produce serious consequences at the brain level. In an effort to clarify the neurobiological mechanisms of their pathogenesis, some studies have suggested the existence of modifications of the cortical architecture in eating disorders, but it is unknown whether the alterations described are a cause or consequence of eating disorders. The main objective of this systematic review is to collect the evidence available about the volumetric alterations of the cerebral cortex in eating disorders in adults and their apparent relationship with the pathogenesis of the disease. Initially, 91 articles were found by a search that included the terms anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder, gray matter, cortical thickness (CT), and brain volume. To pare down the articles, the following inclusion criteria were applied: (1) cortical thickness and/or gray matter volume (GMV) in patients with anorexia, bulimia nervosa, or binge-eating disorder was the main measure of the study; and (2) the sample was adult patients aged 18–65. The exclusion criteria were as follows: (1) articles that did not analyze cortical thickness or gray matter volume; (2) studies with patients with comorbidities; and (3) studies in patients who did not meet the DSM-IV/DSM-V criteria. In the first phase of selection, we proceeded to read the titles and abstracts as a first screen, thereby excluding 62 studies, followed by a complete critical reading of the 29 remaining articles. In this last phase, nine studies were excluded because they did not specify the eating disorder subtype, they included adolescents, or they did not measure GMV or CT. Finally, after the above systematic selection process, 20 articles were included in this review. Despite the methodological heterogeneity of the studies, there was some agreement between them. They showed an overall reduction in GMV in eating disorders, as well as alterations in certain regions of the cerebral cortex. Some of the most often mentioned cortical areas were the frontal, cingulate, and right orbitofrontal cortices, the precuneus, the right insula, and some temporoparietal gyri in cases of AN, with greater cortical involvement in frontotemporal and medial orbitofrontal regions in BN and binge eating disorder. Likewise, certain cortical regions, such as the left inferior frontal gyrus, the precuneus, the right superior motor area, the cingulate cortex, the insula, and the medial orbitofrontal sulcus, often remained altered after recovery from AN, making them potential cortical areas involved in the etiopathogenesis of AN. A reduction in GMV in specific areas of the CNS can inform us about the neurobiological mechanisms that underlie eating disorders as well as give us a better understanding of their possible consequences at the brain level.

Cognitive and Affective Empathy in Huntington's Disease.

Empathy is a multidimensional construct and a key component of social cognition. In Huntington's disease (HD), little is known regarding the phenomenology and the neural correlates of cognitive and affective empathy, and regarding how empathic deficits interact with other behavioral and cognitive manifestations. To explore the cognitive and affective empathy disturbances and related behavioral and neural correlates in HD. Clinical and sociodemographic data were obtained from 36 healthy controls (HC) and 54 gene-mutation carriers (17 premanifest and 37 early-manifest HD). The Test of Cognitive and Affective Empathy (TECA) was used to characterize cognitive (CE) and affective empathy (AE), and to explore their associations with grey matter volume (GMV) and cortical thickness (Cth). Compared to HC, premanifest participants performed significantly worse in perspective taking (CE) and empathic distress (AE). In symptomatic participants, scores were significantly lower in almost all the TECA subscales. Several empathy subscales were associated with the severity of apathy, irritability, and cognitive deficits. CE was associated with GMV in thalamic, temporal, and occipital regions, and with Cth in parietal and temporal areas. AE was associated with GMV in the basal ganglia, limbic, occipital, and medial orbitofrontal regions, and with Cth in parieto-occipital areas. Cognitive and affective empathy deficits are detectable early, are more severe in symptomatic participants, and involve the disruption of several fronto-temporal, parieto-occipital, basal ganglia, and limbic regions. These deficits are associated with disease severity and contribute to several behavioral symptoms, facilitating the presentation of maladaptive patterns of social interaction.

Gout Is Not Just Arthritis: Abnormal Cortical Thickness and Structural Covariance Networks in Gout.

Background: Hyperuricemia is the cause of gout. The antioxidant and neuroprotective effects of uric acid seem to benefit some patients with central nervous system injury. However, changes in the brain structure have not been discovered in patients with gout.Object: Clarify the changes in cortical thickness in patients with gout and the alteration of the structural covariance networks (SCNs) based on cortical thickness.Methods: We collected structural MRIs of 23 male gout patients and 23 age-matched healthy controls. After calculating and comparing the difference in cortical thickness between the two groups, we constructed and analyzed the cortical thickness covariance networks of the two groups, and we investigated for any changes in SCNs of gout patients.Results: Gout patients have thicker cortices in the left postcentral, left supramarginal, right medial temporal, and right medial orbitofrontal regions; and thinner cortices were found in the left insula, left superior frontal, right pericalcarine, and right precentral regions. In SCN analysis, between-group differences in global network measures showed that gout patients have a higher global efficiency. In regional network measures, more nodes in gout patients have increased centrality. In network hub analysis, we found that the transfer of the core hub area, rather than the change in number, may be the characteristic of the gout's cortical thickness covariance network.Conclusion: This is the first study on changes in brain cortical thickness and SCN based on graph theory in patients with gout. The present study found that, compared with healthy controls, gout patients show regional cortical thinning or thickening, and variation in the properties of the cortical thickness covariance network also changed. These alterations may be the combined effect of disease damage and physiological compensation. More research is needed to fully understand the complex underlying mechanisms of gout brain variation.

Global and Regional Changes in Perivascular Space in Idiopathic and Familial Parkinson's Disease.

The glymphatic system, including the perivascular space (PVS), plays a critical role in brain homeostasis. Although mounting evidence from Alzheimer's disease has supported the potential role of PVS in neurodegenerative disorders, its contribution in Parkinson's disease (PD) has not been fully elucidated. Although idiopathic (IPD) and familial PD (FPD) share similar pathophysiology in terms of protein aggregation, the differential impact of PVS on PD subtypes remains unknown. Our objective was to examine the differences in PVS volume fraction in IPD and FPD compared to healthy controls (HCs) and nonmanifest carriers (NMCs). A total of 470 individuals were analyzed from the Parkinson's Progression Markers Initiative database, including (1) IPD (n = 179), (2) FPD (LRRK2 [leucine-rich repeat kinase 2], glucocerebrosidase, or α-synuclein) (n = 67), (3) NMC (n = 101), and (4) HCs (n = 84). Total PVS volume fraction (%) was compared using parcellation and quantitation within greater white matter volume at global and regional levels in all cortical and subcortical white matter. There was a significant increase in global and regional PVS volume fraction in PD versus non-PD, particularly in FPD versus NMC and LRRK2 FPD versus NMC. Regionally, FPD and NMC differed in the medial orbitofrontal region, as did LRRK2 FPD versus NMC. Non-PD and PD differed in the medial orbitofrontal region and the banks of the superior temporal regions. IPD and FPD differed in the cuneus and lateral occipital regions. Our findings support the role of PVS in PD and highlight a potentially significant contribution of PVS to the pathophysiology of FPD, particularly LRRK2. © 2021 International Parkinson and Movement Disorder Society.

Aberrations of anterior insular cortex functional connectivity in nontreatment-seeking alcoholics

An emergent literature suggests that resting state functional magnetic resonance imaging (rsfMRI) functional connectivity (FC) patterns are aberrant in alcohol use disorder (AUD) populations. The salience network (SAL) is an established set of brain regions prominent in salience attribution and valuation, and includes the anterior insular cortex (AIC). The SAL is thought to play a role in AUD through directing increased attention to interoceptive cues of intoxication. There is very little information on the salience network (SAL) in AUD, and, in particular, there are no data on SAL FC in currently drinking, nontreatment seeking individuals with AUD (NTS). rsfMRI data from 16 NTS and 21 social drinkers (SD) were compared using FC correlation maps from ten seed regions of interest in the bilateral AIC. As anticipated, SD subjects demonstrated greater insular FC with frontal and parietal regions. We also found that, compared to SD, NTS had higher insular FC with hippocampal and medial orbitofrontal regions. The apparent overactivity in brain networks involved in salience, learning, and behavioral control in NTS suggests possible mechanisms in the development and maintenance of AUD.

Oral and written narrative comprehension in left-brain damaged individuals and brain volumes correlates

Oral and written narrative comprehension in left-brain damaged individuals and brain volumes correlates

Exploratory structural assessment in craniocervical dystonia: Global and differential analyses.

IntroductionOur goal was to investigate the cortical thickness and subcortical volume in subjects with craniocervical dystonia and its subgroups.MethodsWe studied 49 subjects, 17 with cervical dystonia, 18 with blepharospasm or oromandibular dystonia, and 79 healthy controls. We performed a whole group analysis, followed by a subgroup analysis. We used Freesurfer software to measure cortical thickness, subcortical volume and to perform a primary exploratory analysis in the craniocervical dystonia group, complemented by a region of interest analysis. We also performed a secondary analysis, with data generated from Freesurfer for subgroups, corrected by false discovery rate. We then performed an exploratory generalized linear model with significant areas for the previous steps using clinical features as independent variables.ResultsThe primary exploratory analysis demonstrated atrophy in visual processing regions in craniocervical dystonia. The secondary analysis demonstrated atrophy in motor, sensory, and visual regions in blepharospasm or oromandibular dystonia, as well as in limbic regions in cervical dystonia. Cervical dystonia patients also had greater cortical thickness than blepharospasm or oromandibular dystonia patients in frontal pole and medial orbitofrontal regions. Finally, we observed an association between precuneus, age of onset of dystonia and age at the MRI exam, in craniocervical dystonia; between motor and limbic regions and age at the exam, clinical score and time on botulinum toxin in cervical dystonia and sensory regions and age of onset and time on botulinum toxin in blepharospasm or oromandibular dystonia.ConclusionsWe detected involvement of visual processing regions in craniocervical dystonia, and a pattern of involvement in cervical dystonia and blepharospasm or oromandibular dystonia, including motor, sensory and limbic areas. We also showed an association of cortical thickness atrophy and younger onset age, older age at the MRI exam, higher clinical score and an uncertain association with longer time on botulinum toxin.

Reproducibility of quantitative structural and physiological MRImeasurements.

IntroductionQuantitative longitudinal magnetic resonance imaging and spectroscopy (MRI/S) is used to assess progress of brain disorders and treatment effects. Understanding the significance of MRI/S changes requires knowledge of the inherent technical and physiological consistency of these measurements. This longitudinal study examined the variance and reproducibility of commonly used quantitative MRI/S measurements in healthy subjects while controlling physiological and technical parameters.MethodsTwenty‐five subjects were imaged three times over 5 days on a Siemens 3T Verio scanner equipped with a 32‐channel phase array coil. Structural (T1, T2‐weighted, and diffusion‐weighted imaging) and physiological (pseudocontinuous arterial spin labeling, proton magnetic resonance spectroscopy) data were collected. Consistency of repeated images was evaluated with mean relative difference, mean coefficient of variation, and intraclass correlation (ICC). Finally, a “reproducibility rating” was calculated based on the number of subjects needed for a 3% and 10% difference.ResultsStructural measurements generally demonstrated excellent reproducibility (ICCs 0.872–0.998) with a few exceptions. Moderate‐to‐low reproducibility was observed for fractional anisotropy measurements in fornix and corticospinal tracts, for cortical gray matter thickness in the entorhinal, insula, and medial orbitofrontal regions, and for the count of the periependymal hyperintensive white matter regions. The reproducibility of physiological measurements ranged from excellent for most of the magnetic resonance spectroscopy measurements to moderate for permeability‐diffusivity coefficients in cingulate gray matter to low for regional blood flow in gray and white matter.DiscussionThis study demonstrates a high degree of longitudinal consistency across structural and physiological measurements in healthy subjects, defining the inherent variability in these commonly used sequences. Additionally, this study identifies those areas where caution should be exercised in interpretation. Understanding this variability can serve as the basis for interpretation of MRI/S data in the assessment of neurological disorders and treatment effects.

Brain alterations in low-frequency fluctuations across multiple bands in obsessive compulsive disorder.

The extent of functional abnormalities in frontal-subcortical circuits in obsessive-compulsive disorder (OCD) is still unclear. Although neuroimaging studies, in general, and resting-state functional Magnetic Resonance Imaging (rs-fMRI), in particular, have provided relevant information regarding such alterations, rs-fMRI studies have been typically limited to the analysis of between-region functional connectivity alterations at low-frequency signal fluctuations (i.e., <0.08Hz). Conversely, the local attributes of Blood Oxygen Level Dependent (BOLD) signal across different frequency bands have been seldom studied, although they may provide valuable information. Here, we evaluated local alterations in low-frequency fluctuations across different oscillation bands in OCD. Sixty-five OCD patients and 50 healthy controls underwent an rs-fMRI assessment. Alterations in the fractional amplitude of low-frequency fluctuations (fALFF) were evaluated, voxel-wise, across four different bands (from 0.01Hz to 0.25Hz). OCD patients showed decreased fALFF values in medial orbitofrontal regions and increased fALFF values in the dorsal-medial prefrontal cortex (DMPFC) at frequency bands <0.08Hz. This pattern was reversed at higher frequencies, where increased fALFF values also appeared in medial temporal lobe structures and medial thalamus. Clinical variables (i.e., symptom-specific severities) were associated with fALFF values across the different frequency bands. Our findings provide novel evidence about the nature and regional distribution of functional alterations in OCD, which should contribute to refine neurobiological models of the disorder. We suggest that the evaluation of the local attributes of BOLD signal across different frequency bands may be a sensitive approach to further characterize brain functional alterations in psychiatric disorders.

Brain Cortical Thickness Differences in Adolescent Females with Substance Use Disorders.

Some youths develop multiple substance use disorders early in adolescence and have severe, persistent courses. Such youths often exhibit impulsivity, risk-taking, and problems of inhibition. However, relatively little is known about the possible brain bases of these behavioral traits, especially among females.MethodsWe recruited right-handed female patients, 14–19 years of age, from a university-based treatment program for youths with substance use disorders and community controls similar for age, race and zip code of residence. We obtained 43 T1-weighted structural brain images (22 patients and 21 controls) to examine group differences in cortical thickness across the entire brain as well as six a priori regions-of-interest: 1) medial orbitofrontal cortex; 2) rostral anterior cingulate cortex; and 3) middle frontal cortex, in each hemisphere. Age and IQ were entered as nuisance factors for all analyses.ResultsA priori region-of-interest analyses yielded no significant differences. However, whole-brain group comparisons revealed that the left pregenual rostral anterior cingulate cortex extending into the left medial orbitofrontal region (355.84 mm2 in size), a subset of two of our a priori regions-of-interest, was significantly thinner in patients compared to controls (vertex-level threshold p = 0.005 and cluster-level family wise error corrected threshold p = 0.05). The whole-brain group differences did not survive after adjusting for depression or externalizing scores. Whole-brain within-patient analyses demonstrated a positive association between cortical thickness in the left precuneus and behavioral disinhibition scores (458.23 mm2 in size).ConclusionsAdolescent females with substance use disorders have significant differences in brain cortical thickness in regions engaged by the default mode network and that have been associated with problems of emotional dysregulation, inhibition, and behavioral control in past studies.

From Vivaldi to Beatles and back: Predicting lateralized brain responses to music

We aimed at predicting the temporal evolution of brain activity in naturalistic music listening conditions using a combination of neuroimaging and acoustic feature extraction. Participants were scanned using functional Magnetic Resonance Imaging (fMRI) while listening to two musical medleys, including pieces from various genres with and without lyrics. Regression models were built to predict voxel-wise brain activations which were then tested in a cross-validation setting in order to evaluate the robustness of the hence created models across stimuli. To further assess the generalizability of the models we extended the cross-validation procedure by including another dataset, which comprised continuous fMRI responses of musically trained participants to an Argentinean tango. Individual models for the two musical medleys revealed that activations in several areas in the brain belonging to the auditory, limbic, and motor regions could be predicted. Notably, activations in the medial orbitofrontal region and the anterior cingulate cortex, relevant for self-referential appraisal and aesthetic judgments, could be predicted successfully. Cross-validation across musical stimuli and participant pools helped identify a region of the right superior temporal gyrus, encompassing the planum polare and the Heschl's gyrus, as the core structure that processed complex acoustic features of musical pieces from various genres, with or without lyrics. Models based on purely instrumental music were able to predict activation in the bilateral auditory cortices, parietal, somatosensory, and left hemispheric primary and supplementary motor areas. The presence of lyrics on the other hand weakened the prediction of activations in the left superior temporal gyrus. Our results suggest spontaneous emotion-related processing during naturalistic listening to music and provide supportive evidence for the hemispheric specialization for categorical sounds with realistic stimuli. We herewith introduce a powerful means to predict brain responses to music, speech, or soundscapes across a large variety of contexts.

Adversive seizures associated with periodic lateralised epileptiform discharges (PLEDs) after left orbital contusion

We report a patient who presented with adversive seizures associated with periodic lateralised epileptiform discharges (PLEDs), a month after head trauma. The PLEDs predominantly involving the left frontal contacts became more frequent at the onset of adversive seizures during EEG. Brain MRI demonstrated a contusion scar in the left orbital cortex with reduced diffusion, not only around this orbital lesion but also in the ipsilateral anteromedial thalamus. Single photon emission computed tomography revealed focal cerebral hyperperfusion in the left medial orbitofrontal region, basal ganglia, and thalamus. The abnormal metabolism involving the thalamus and striatum could be associated with the ipsilateral orbital contusion and might have been caused by cortical-subcortical, trans-synaptic hyperactivity. Further studies are warranted to determine the role of subcortical structures in the generation of PLEDs and adversive seizures. [Published with video sequences].

Rey Visual Design Learning Test performance correlates with white matter structure.

Studies exploring relation of visual memory to white matter are extensively lacking. The Rey Visual Design Learning Test (RVDLT) is an elementary motion, colour and word independent visual memory test. It avoids a significant contribution from as many additional higher order visual brain functions as possible to visual performance, such as three-dimensional, colour, motion or word-dependent brain operations. Based on previous results, we hypothesised that test performance would be related with white matter of dorsal hippocampal commissure, corpus callosum, posterior cingulate, superior longitudinal fascicle and internal capsule. In 14 healthy subjects, we measured intervoxel coherence (IC) by diffusion tensor imaging as an indication of connectivity and visual memory performance measured by the RVDLT. IC considers the orientation of the adjacent voxels and has a better signal-to-noise ratio than the commonly used fractional anisotropy index. Using voxelwise linear regression analyses of the IC values, we found a significant and direct relationship between 11 clusters and visual memory test performance. The fact that memory performance correlated with white matter structure in left and right dorsal hippocampal commissure, left and right posterior cingulate, right callosal splenium, left and right superior longitudinal fascicle, right medial orbitofrontal region, left anterior cingulate, and left and right anterior limb of internal capsule emphasises our hypothesis. Our observations in healthy subjects suggest that individual differences in brain function related to the performance of a task of higher cognitive demands might partially be associated with structural variation of white matter regions.

Positron Emission Tomography Metabolic Correlates of Apathy in Alzheimer Disease

Apathy is the most common neuropsychiatric manifestation in Alzheimer disease (AD). Clinical, single-photon emission computed tomography, magnetic resonance imaging, and pathologic studies of apathy in AD have suggested an association with frontal dysfunction, most supportive of anterior cingulate abnormalities, but without a definitive localization. To examine the association between apathy and cortical metabolic rate on positron emission tomography in AD. Forty-one subjects with probable AD underwent [(18)F] fluorodeoxyglucose positron emission tomography imaging and neuropsychiatric and cognitive assessments. Global subscale scores from the Scale for the Assessment of Negative Symptoms in Alzheimer Disease were used to designate the absence or presence of clinically meaningful apathy. Whole-brain voxel-based analyses were performed using statistical parametric mapping (SPM2; Wellcome Department of Imaging Neuroscience, London, England), which yielded significance maps comparing the 2 groups. Twenty-seven (66%) subjects did not have apathy, whereas 14 (34%) had apathy. Statistical parametric mapping analysis revealed significant reduced activity in the bilateral anterior cingulate region extending inferiorly to the medial orbitofrontal region (P < .001) and the bilateral medial thalamus (P = .04) in subjects with apathy. The results of the statistical parametric mapping analysis remained the same after individually covarying for the effects of global cognitive impairment, depressed mood, and education. Apathy in AD is associated with reduced metabolic activity in the bilateral anterior cingulate gyrus and medial orbitofrontal cortex and may be associated with reduced activity in the medial thalamus. These results reinforce the confluence of evidence from other investigational modalities in implicating medial frontal dysfunction and related neuronal circuits in the neurobiology of apathy in AD and other neuropsychiatric diseases.

Distinct and common cortical activations for multimodal semantic categories

If semantic representations are based on particular types of perceptual features, then category knowledge that arises from multimodal sensory experiences should rely on distinct and common sensory brain regions depending on the features involved. Using a similarity-based generation-and-comparison task, we found that semantic categories activated cortical areas associated with taste and smell, biological motion, and visual processing. Fruit names specifically activated medial orbitofrontal regions associated with taste and smell. Labels for body parts and clothing activated lateral temporal occipitoparietal areas associated with perceiving the human body. More generally, visually biased categories activated ventral temporal regions typically ascribed to visual object recognition, whereas functional categories activated lateral frontotemporal areas previously associated with the representation of usage properties. These results indicate that semantic categories that are distinguished by particular perceptual properties rely on distinct cortical regions, whereas semantic categories that rely on similar types of features depend on common brain areas.