Lateral Occipital Area Research Articles

The Emergence of Tuning to Global Shape Properties of Radial Frequency Patterns in the Ventral Visual Pathway.

Radial frequency (RF) patterns, created by sinusoidal modulations of a circle's radius, are processed globally when RF is low. These closed shapes therefore offer a useful way to interrogate the human visual system for global processing of curvature. RF patterns elicit greater responses than those to radial gratings in V4 and more anterior face-selective regions of the ventral visual pathway. This is largely consistent with work on nonhuman primates showing curvature processing emerges in V4, but is evident also higher up the ventral visual stream. Rather than contrasting RF patterns with other stimuli, we presented them at varied frequencies in a regimen that allowed tunings to RF to be derived from 8 human participants (3 female). We found tuning to low RF in lateral occipital areas and to some extent in V4. In a control experiment, we added a high-frequency ripple to the stimuli disrupting the local contour. Low-frequency tuning to these stimuli remained in the ventral visual stream, underscoring its role in global processing of shape curvature. We then used representational similarity analysis to show that, in lateral occipital areas, the neural representation was related to stimulus similarity, when it was computed with a model that captured how stimuli are perceived. We therefore show that global processing of shape curvature emerges in the ventral visual stream as early as V4, but is found more strongly in lateral occipital regions, which exhibit responses and representations that relate well to perception.SIGNIFICANCE STATEMENT We show that tuning to low radial frequencies, known to engage global shape processing mechanisms, was localized to lateral occipital regions. When low-level stimulus properties were accounted for such tuning emerged in V4 and LO2 in addition to the object-selective region LO. We also documented representations of global shape properties in lateral occipital regions, and these representations were predicted well by a proxy of the perceptual difference between the stimuli.

Increased parietal and occipital lobe gyrification predicts conversion to syndromal psychosis in a clinical high-risk cohort.

Local gyrification index (lGI), indicative of the degree of cortical folding is a proxy marker for early cortical neurodevelopmental abnormalities. We studied the difference in lGI between those who do and do not convert to psychosis (non-converters) in a clinical high-risk (CHR) cohort, and whether lGI predicts conversion to psychosis. Seventy-two CHR participants with attenuated positive symptom syndrome were followed up for two years. The difference in baseline whole-brain lGI was examined on the T1-weighted MRIs between, i)CHR (N=72) and healthy controls (N=19), ii)Converters to psychosis (N=24) and non-converters (N=48), adjusting for age and sex, on Freesurfer-6.0. The significant cluster obtained in the converters versus non-converters comparison was registered as a region of interest to individual images of all 72 participants and lGI values were extracted from this region. A cox proportional hazards model was applied with these values to study whether lGI predicts conversion to psychosis. lGI was not different between CHR and healthy controls. lGI was increased in converters in the right-sided inferior parietal and lateral occipital areas (corrected cluster-wise-p-value=0.009, cohen's f=0.42) compared to non-converters, which significantly increased the risk of onset of psychosis (p=0.029, hazard ratio=1.471). Increased gyrification in the right-sided inferior parietal and lateral occipital area differentiates converters to psychosis in CHR, significantly increasing the risk of conversion to psychosis. This measure may reflect underlying traits in parts of the brain that develop earliest in-utero (parietal and occipital), conferring a heightened vulnerability to convert to syndromal psychosis subsequently.

Effects of nonsocial and circumscribed interest images on neural mechanisms of emotion regulation in autistic adults.

Emotion dysregulation is commonly reported among autistic individuals. Prior work investigating the neurofunctional mechanisms of emotion regulation (ER) in autistic adults has illustrated alterations in dorsolateral prefrontal cortex (dlPFC) activity, as well as concurrent atypical patterns of activation in subcortical regions related to affect during cognitive reappraisal of social images. Whereas most research examining ER in autism has focused on regulation of negative emotions, the effects of regulating positive emotions has been generally understudied. This is surprising given the relevance of positive motivational states to understanding circumscribed interests (CI) in autism. Accordingly, the purpose of this study was to use fMRI with simultaneous eye-tracking and pupillometry to investigate the neural mechanisms of ER during passive viewing and cognitive reappraisal of a standardized set of nonsocial images and personalized (self-selected) CI images. The autistic group demonstrated comparatively reduced modulation of posterior cingulate cortex (PCC) activation during cognitive reappraisal of CI images compared to viewing of CI, although no eye-tracking/pupillometry differences emerged between-groups. Further, the autistic group demonstrated increased PCC connectivity with left lateral occipital and right supramarginal areas when engaging in cognitive reappraisal vs. viewing CI. In autistic adults, CI may be differentially modulated via PCC. Considering the documented role of the PCC as a core hub of the default mode network, we further postulate that ER of CI could potentially be related to self-referential cognition.

Representational structure of fMRI/EEG responses to dynamic facial expressions

Face perception provides an excellent example of how the brain processes nuanced visual differences and transforms them into behaviourally useful representations of identities and emotional expressions. While a body of literature has looked into the spatial and temporal neural processing of facial expressions, few studies have used a dimensionally varying set of stimuli containing subtle perceptual changes. In the current study, we used 48 short videos varying dimensionally in their intensity and category (happy, angry, surprised) of expression. We measured both fMRI and EEG responses to these video clips and compared the neural response patterns to the predictions of models based on image features and models derived from behavioural ratings of the stimuli. In fMRI, the inferior frontal gyrus face area (IFG-FA) carried information related only to the intensity of the expression, independent of image-based models. The superior temporal sulcus (STS), inferior temporal (IT) and lateral occipital (LO) areas contained information about both expression category and intensity. In the EEG, the coding of expression category and low-level image features were most pronounced at around 400 ms. The expression intensity model did not, however, correlate significantly at any EEG timepoint. Our results show a specific role for IFG-FA in the coding of expressions and suggest that it contains image and category invariant representations of expression intensity.

Normative quantitative relaxation atlases for characterization of cortical regions using magnetic resonance fingerprinting.

Quantitative magnetic resonance (MR) has been used to study cyto- and myelo-architecture of the human brain non-invasively. However, analyzing brain cortex using high-resolution quantitative MR acquisition can be challenging to perform using 3T clinical scanners. MR fingerprinting (MRF) is a highly efficient and clinically feasible quantitative MR technique that simultaneously provides T1 and T2 relaxation maps. Using 3D MRF from 40 healthy subjects (mean age = 25.6 ± 4.3years) scanned on 3T magnetic resonance imaging, we generated whole-brain gyral-based normative MR relaxation atlases and investigated cortical-region-based T1 and T2 variations. Gender and age dependency of T1 and T2 variations were additionally analyzed. The coefficient of variation of T1 and T2 for each cortical-region was 3.5% and 7.3%, respectively, supporting low variability of MRF measurements across subjects. Significant differences in T1 and T2 were identified among 34 brain regions (P < 0.001), lower in the precentral, postcentral, paracentral lobule, transverse temporal, lateral occipital, and cingulate areas, which contain sensorimotor, auditory, visual, and limbic functions. Significant correlations were identified between age and T1 and T2 values. This study established whole-brain MRF T1 and T2 atlases of healthy subjects using a clinical 3T scanner, which can provide a quantitative and region-specific baseline for future brain studies and pathology detection.

Modeling the Hemodynamic Response Function Using EEG-fMRI Data During Eyes-Open Resting-State Conditions and Motor Task Execution

Being able to accurately quantify the hemodynamic response function (HRF) that links the blood oxygen level dependent functional magnetic resonance imaging (BOLD-fMRI) signal to the underlying neural activity is important both for elucidating neurovascular coupling mechanisms and improving the accuracy of fMRI-based functional connectivity analyses. In particular, HRF estimation using BOLD-fMRI is challenging particularly in the case of resting-state data, due to the absence of information about the underlying neuronal dynamics. To this end, using simultaneously recorded electroencephalography (EEG) and fMRI data is a promising approach, as EEG provides a more direct measure of neural activations. In the present work, we employ simultaneous EEG-fMRI to investigate the regional characteristics of the HRF using measurements acquired during resting conditions. We propose a novel methodological approach based on combining distributed EEG source space reconstruction, which improves the spatial resolution of HRF estimation and using block-structured linear and nonlinear models, which enables us to simultaneously obtain HRF estimates and the contribution of different EEG frequency bands. Our results suggest that the dynamics of the resting-state BOLD signal can be sufficiently described using linear models and that the contribution of each band is region specific. Specifically, it was found that sensory-motor cortices exhibit positive HRF shapes, whereas the lateral occipital cortex and areas in the parietal cortex, such as the inferior and superior parietal lobule exhibit negative HRF shapes. To validate the proposed method, we repeated the analysis using simultaneous EEG-fMRI measurements acquired during execution of a unimanual hand-grip task. Our results reveal significant associations between BOLD signal variations and electrophysiological power fluctuations in the ipsilateral primary motor cortex, particularly for the EEG beta band, in agreement with previous studies in the literature.

The role of ventral stream areas for viewpoint-invariant object recognition

Object constancy is one of the most crucial mechanisms of the human visual system enabling viewpoint invariant object recognition. However, the neuronal foundations of object constancy are widely unknown. Research has shown that the ventral visual stream is involved in processing of various kinds of object stimuli and that several regions along the ventral stream are possibly sensitive to the orientation of an object in space. To systematically address the question of viewpoint sensitive object perception, we conducted a study with stroke patients as well as an fMRI experiment with healthy participants applying object stimuli in several spatial orientations, for example in typical and atypical viewing conditions. In the fMRI experiment, we found stronger BOLD signals and above-chance classification accuracies for objects presented in atypical viewing conditions in fusiform face sensitive and lateral occipito-temporal object preferring areas. In the behavioral patient study, we observed that lesions of the right fusiform gyrus were associated with lower performance in object recognition for atypical views. The complementary results from both experiments emphasize the contributions of fusiform and lateral-occipital areas to visual object constancy and indicate that visual object constancy is particularly enabled through increased neuronal activity and specific activation patterns for objects in demanding viewing conditions.

Electroencephalography for Early Detection of Alzheimer's Disease in Subjective Cognitive Decline.

Early detection of subjective cognitive decline (SCD) due to Alzheimer's disease (AD) is important for clinical research and effective prevention and management. This study examined if quantitative electroencephalography (qEEG) could be used for early detection of AD in SCD. Participants with SCD from 6 dementia clinics in Korea were enrolled. 18F-florbetaben brain amyloid positron emission tomography (PET) was conducted for all the participants. qEEG was performed to measure power spectrum and source cortical activity. The present study included 95 participants aged over 65 years, including 26 amyloid PET (+) and 69 amyloid PET (-). In participants with amyloid PET (+), relative power at delta band was higher in frontal (p=0.025), parietal (p=0.005), and occipital (p=0.022) areas even after adjusting for age, sex, and education. Source activities of alpha 1 band were significantly decreased in the bilateral fusiform and inferior temporal areas, whereas those of delta band were increased in the bilateral cuneus, pericalcarine, lingual, lateral occipital, precuneus, posterior cingulate, and isthmus areas. There were increased connections between bilateral precuneus areas but decreased connections between left rostral middle frontal area and bilateral frontal poles at delta band in participants with amyloid PET (+) showed. At alpha 1 band, there were decreased connections between bilateral entorhinal areas after adjusting for covariates. SCD participants with amyloid PET (+) showed increased delta and decreased alpha 1 activity. qEEG is a potential means for predicting amyloid pathology in SCD. Further longitudinal studies are needed to confirm these findings.

Interocular Grouping in Perceptual Rivalry Localized with fMRI

Bistable perception refers to a broad class of dynamically alternating visual illusions that result from ambiguous images. These illusions provide a powerful method to study the mechanisms that determine how visual input is integrated over space and time. Binocular rivalry occurs when subjects view different images in each eye, and a similar experience called stimulus rivalry occurs even when the left and right images are exchanged at a fast rate. Many previous studies have identified with fMRI a network of cortical regions that are recruited during binocular rivalry, relative to non-rivalrous control conditions (termed replay) that use physically changing stimuli to mimic rivalry. However, we show here for the first time that additional cortical areas are activated when subjects experience rivalry with interocular grouping. When interocular grouping occurs, activation levels broadly increase, with a slight shift towards right hemisphere lateralization. Moreover, direct comparison of binocular rivalry with and without grouping highlights strong focused activity in the intraparietal sulcus and lateral occipital areas, such as right-sided retinotopic visual areas LO1 and IP2, as well as activity in left-sided visual areas LO1, and IP0-IP2. The equivalent analyses for comparable stimulus (eye-swap) rivalry showed very similar results; the main difference is greater recruitment of the right superior parietal cortex for binocular rivalry, as previously reported. Thus, we found minimal interaction between the novel networks isolated here for interocular grouping, and those previously attributed to stimulus and binocular rivalry. We conclude that spatial integration (i.e,. image grouping/segmentation) is a key function of lateral occipital/intraparietal cortex that acts similarly on competing binocular stimulus representations, regardless of fast monocular changes.

The neural basis of hazard perception differences between novice and experienced drivers - An fMRI study.

The neural mechanisms underlying hazard perception are poorly understood as to how experience leads to better driving skills. In this study we used functional magnetic resonance imaging (fMRI) to examine experience-related changes in brain activation during hazard perception task between novice and aged drivers. Additionally, region of interest (ROI) and seed-to-voxel analyses were conducted to examine experience-related functional connectivity changes during visual attention and saliency networks between novice (n=15, age 22.13 ± 3.38 years years) and experienced (n=16, age 41.44 ± 5.83 years) drivers. Experienced drivers had significantly lower hazard perception reaction time (1.32 ± 1.09 s) and miss rates (11.42 ± 8.36 %) compared to the novice (3.58 ± 1.45 s and 39.67 ± 15.72 %, respectively). Blood oxygen level dependent (BOLD) activation increased in occipital, parietal and frontal areas when executing hazard perception task in both groups. In general, during the task execution, experienced drivers showed greater activation in the occipital lobe, supramarginal gyrus (SMG), right anterior insular cortex (AIC), anterior cingulate cortex (ACC) and cerebellar regions compared to the novice drivers indicating more efficient visual attention and decision-making process during hazard perception task. Seed based functional analyses during the hazard perception task revealed greater connectivity between the ACC and the entire salience network (visual attention network) in the experienced group. Additionally, ACC had higher functional connectivity with the right frontal eye field (FEF), bilateral intraparietal sulcus (IPS) and lateral occipital areas in the experienced group. Our results suggest that better hazard perception in the experienced drivers is due to increase in the activation of executive attention regions and higher functional connectivity between bilateral occipital cortices and salience network. In conclusion, better hazard perception is highly dependent on emotional awareness, perception of motion velocity, spatial representation of the environment and executing control.

Differences in brain surface area and cortical volume between suicide attempters and non-attempters with major depressive disorder

The neurobiological causes underlying suicidal behaviors in major depressive disorder (MDD) have not been identified. This study was performed to investigate the differences in brain cortical thickness, surface area, and volume between suicide attempters and non-attempters with MDD. We performed magnetic resonance imaging (MRI) in 38 MDD patients (18–65 years old; 18 male, 20 female) with and without a history of suicide attempts. FreeSurfer software was used to compare the cortical thickness, surface area, and volume of 19 suicide attempters with MDD and 19 suicide non-attempters with MDD, while controlling for age, sex, mean area (or volume), and severity of depression. Compared with suicide non-attempters, suicide attempters with MDD exhibited a larger surface area in the left postcentral area and left lateral occipital area and a larger cortical volume in the left postcentral area and left lateral orbitofrontal area. Suicide attempters exhibited a smaller surface area in the left superior frontal area than suicide non-attempters. The present findings provide evidence for neuroanatomical risk factors of suicide in MDD. Further research to replicate these results and determine the mechanisms underlying these findings is needed.

The left lateral occipital cortex exhibits decreased thickness in children with sensorineural hearing loss

Patients with sensorineural hearing loss (SNHL) tend to show language delay, executive functioning deficits, and visual cognitive impairment, even after intervention with hearing amplification and cochlear implants, which suggest altered brain structures and functions in SNHL patients. In this study, we investigated structural brain MRI in 30 children with SNHL (18 mild to moderate [M-M] SNHL and 12 moderately severe to profound [M–P] SNHL) by comparing gender- and age-matched normal controls (NC). Region-based analyses did not show statistically significant differences in volumes of the cerebrum, basal ganglia, cerebellum, and the ventricles between SNHL and NC. On surface-based analyses, the global and lobar cortical surface area, thickness, and volumes were not statistically significantly different between SNHL and NC participants. Regional surface areas, cortical thicknesses, and cortical volumes were statistically significantly smaller in M–P SNHL compared to NC in the left middle occipital cortex, and left inferior occipital cortex after a correction for multiple comparisons using random field theory (p < 0.02). These regions were identified as areas known to be related to high level visual cognition including the human middle temporal area, lateral occipital area, occipital face area, and V8. The observed regional decreased thickness in M–P SNHL may be associated with dysfunctions of visual cognition in SNHL detectable in a clinical setting.

&lt;p&gt;Modulations of emotional attention and spatial attention on human visual cortical activities&lt;/p&gt;

Background: Spatial attention could enhance the neural activities of attended locations in human visual cortex. As a salient stimulus, emotional image could enhance the responses in amygdala and visual areas. However, few studies examined the interaction of the attentional effects induced by emotional stimuli and spatial cues on the neural responses in visual areas.Methods: In the present study, we used functional magnetic resonance imaging (fMRI) to examine the combined and separated effects of emotional image and spatial cue on the activities in human visual areas. A revised Posner cueing paradigm was utilized. Each participant viewed a fearful image and a peaceful image simultaneously in left and right visual fields. A spatial cue of two dots was then presented in one of the image positions. In this manner, the attentional effects for emotional image and spatial cue could be isolated and combined.Results: The results showed that spatial cue enhanced the responses in V4, intraparietal sulcus (IPS) and lateral occipital area (LO), while emotional image could enhance the responses in V3, V4 and LO. Importantly, no significant interactions were found in any of the visual areas.Conclusion: Our results indicate that the two kinds of attentional modulation might not be affected by each other. These findings shed light on the neural mechanism of the emotional attention.

Anatomy and white matter connections of the inferior frontal gyrus.

The inferior frontal gyrus (IFG) is involved in the evaluation of linguistic, interoceptive, and emotional information. A detailed understanding of its subcortical white matter anatomy could improve postoperative morbidity related to surgery in and around this gyrus. Through GQI-based fiber tracking validated by gross anatomical dissection as ground truth, we characterized the fiber tracts of the IFG based on relationships to other well-known neuroanatomic structures. Diffusion imaging from the Human Connectome Project for 10 healthy adult controls was used for fiber tracking analysis. We evaluated the IFG as a whole based on its connectivity with other regions. All tracts were mapped in both hemispheres, and a lateralization index was calculated based on resultant tract volumes. Ten cadaveric dissections were then performed using a modified Klingler technique to demonstrate the location of major tracts. We identified four major connections of the IFG: a white matter bundle corresponding the frontal aslant tract connecting to the superior frontal gyrus; the superior longitudinal fasciculus connecting to the inferior parietal lobule, lateral occipital area, posterior temporal areas, and the temporal pole; the inferior fronto-occipital fasciculus connecting to the cuneus and lingual gyrus; and the uncinate fasciculus connecting to the temporal pole. A callosal fiber bundle connecting the inferior frontal gyri bilaterally was also identified. The IFG is an important region implicated in a variety of tasks including language processing, speech production, motor control, interoceptive awareness, and semantic processing. Postsurgical outcomes related to this region may be better understood in the context of the fiber-bundle anatomy highlighted in this study. Clin. Anat. 32:546-556, 2019. © 2019 Wiley Periodicals, Inc.

Dissociating the role of dorsal and ventral visual streams in object lifting and weight perception

Event Abstract Back to Event Dissociating the role of dorsal and ventral visual streams in object lifting and weight perception Vonne Van Polanen1*, Guy Rens1 and Marco Davare1 1 KU Leuven, Belgium When sequentially lifting a series of differently weighted objects, our fingertip forces are typically scaled according to the weight of the previously lifted object, an effect often referred to as sensorimotor memory [2]. For instance, force rates are higher after the lift of a heavy compared to a light object. Recently, we showed that this effect on force parameters also changes perceptual estimates, where objects are judged lighter after the lift of a heavy compared to a light weight [3]. Here, we aimed to investigate the causal role of the dorsal vs. ventral visual streams in these processes, given they are classically involved in computing motor vs. perceptual parameters, respectively. We used transcranial magnetic stimulation (TMS) to investigate the contribution of the left anterior intraparietal sulcus (aIPS) and lateral occipital (LO) areas, which are important nodes for processing hand-object interactions in the dorsal and ventral streams. Subjects received TMS to either aIPS or LO. Neuronavigation (Brainsight) was used to localize our TMS targets on individual structural brain imaging scans. The left aIPS was defined anatomically as the intersection between the intraparietal and postcentral sulci and LO was located using previously published functional coordinates [1]. Subjects were asked to grip and lift equally sized but differently weighted (light, 2N, or heavy, 6N) objects in a pseudo-randomized order and provide a weight estimate on a self-chosen scale. During object lifting, TMS was applied in a burst of 3 pulses (10Hz) at 120% of the active motor threshold. Three stimulation conditions were compared for each brain area, with stimulation at object contact (dynamic phase), 500 ms after object lift-off (static phase) or no stimulation. We quantified the effect of TMS on perceptual weight estimates, peak grip and load force rates, loading phase duration and mean grip force during stable hold. For each parameter, a mixed ANOVA was performed with TMS target (aIPS or LO) as between-subject factor and TMS condition (dynamic, static, or no stimulation) and object order (light-light, heavy-light, light-heavy, or heavy-heavy) as within-subject factors. When previously lifting a heavy object, peak grip and load force rates were higher and loading phase durations were shorter compared to previously lifting a light object, in line with classical sensorimotor memory effects. It is noteworthy that TMS did not alter this order effect. We only found a general effect of TMS when applied during the dynamic phase, with increased force rate peaks compared to the other TMS conditions. Furthermore, stable grip forces were higher after lifting a heavy object compared to a light one. Interestingly, this effect was cancelled in the aIPS group. No general effect of TMS condition on stable grip force was found. Finally, weight estimations were lower when a light object was preceded by a heavy object compared to a light one, replicating our earlier findings [3]. TMS led to overall lighter weight ratings, independently of the targeted area or timing. Remarkably, the order effect on weight estimations was cancelled when TMS was applied during the static phase over either aIPS or LO. These findings suggest that both aIPS and LO are involved in late phases of object weight perception. Moreover, the role of dorsal and ventral stream areas in mediating sensorimotor memory effects seems limited to aIPS for controlling grip forces in later phases of lifting. Overall, this sheds new light on the interactions between brain networks mediating action and perception during object manipulation.

Structure, asymmetry, and connectivity of the human temporo-parietal aslant and vertical occipital fasciculi.

We previously proposed a bipartite 'dorsal-ventral' model of human arcuate fasciculus (AF) morphology. This model does not, however, account for the 'vertical,' temporo-parietal subdivision of the AF described in earlier dissection and tractographic studies. In an effort to address the absence of the vertical AF (VAF) within 'dorsal-ventral' nomenclature, we conducted a dedicated tractographic and white-matter dissection study of this tract and another short, vertical, posterior-hemispheric fascicle: the vertical occipital fasciculus (VOF). We conducted atlas-based, non-tensor, deterministic tractography in 30 single subjects from the Human Connectome Project database and verified our results using an average diffusion atlas compiled from 842 separate normal subjects. We also performed white-matter dissection in four post-mortem specimens. Our tractography results demonstrate that the VAF is, in fact, a bipartite system connecting the ventral parietal and temporal regions, with variable connective, and no volumetric lateralization. The VOF is a non-lateralized, non-segmented system connecting lateral occipital areas with basal-temporal regions. Importantly, the VOF was spatially dissociated from the VAF. As the VAF demonstrates no overall connective or volumetric lateralization, we postulate its distinction from the AF system and propose its re-naming to the 'temporo-parietal aslant tract,' (TPAT), with unique dorsal and ventral subdivisions. Our tractography results were supported by diffusion atlas and white-matter dissection findings.

Altered Default Mode and Sensorimotor Network Connectivity With Striatal Subregions in Primary Insomnia: A Resting-State Multi-Band fMRI Study.

Background: Primary insomnia is a high prevalent sleep disorder. Disturbed brain activity during reward, emotional, and cognitive processing have been observed in insomnia patients. Studies have implicated a critical role of the striatum in these dysfunctions. However, there have been no direct investigations on the whole-brain functional connectivity (FC) of the striatum in insomnia.Methods: We analyzed the group differences in the FC images of 6 predefined striatal subregions based on the multi-band resting-state fMRI data of 18 insomnia patients and 16 healthy controls.Results: We found increased positive FC in the bilateral medial frontal gyrus for bilateral dorsal caudate (DC) and left inferior ventral striatum (VS) subregions, but increased negative FC in the bilateral inferior parietal lobe for the left inferior VSi and right dorsal caudal putamen (DCP) subregions, and in the lateral temporal, occipital, and primary sensorimotor areas for the bilateral DC and left superior VS subregions. The FC between the right DCP and right inferior parietal lobe showed significant positive correlation with Pittsburgh Sleep Quality Index (PSQI).Conclusion: The findings indicate disturbed striatal FC with the default mode network (DMN), the visual and somatosensory areas in insomnia, which likely reflects an inappropriate reward or emotional significance attribute to self-reflection, episodic memory, sensory-perception processes. The altered striatal FC might increase the risk of insomnia patients to develop depression and anxiety.

Decoding natural scenes based on sounds of objects within scenes using multivariate pattern analysis

Scene recognition plays an important role in spatial navigation and scene classification. It remains unknown whether the occipitotemporal cortex could represent the semantic association between the scenes and sounds of objects within the scenes. In this study, we used the functional magnetic resonance imaging (fMRI) technique and multivariate pattern analysis to assess whether diff ; ;erent scenes could be discriminated based on the patterns evoked by sounds of objects within the scenes. We found that patterns evoked by scenes could be predicted with patterns evoked by sounds of objects within the scenes in the posterior fusiform area (pF), lateral occipital area (LO) and superior temporal sulcus (STS). The further functional connectivity analysis suggested significant correlations between pF, LO and parahippocampal place area (PPA) except that between STS and other three regions under the scene and sound conditions. A distinct network in processing scenes and sounds was discovered using a seed-to-voxel analysis with STS as the seed. This study may provide a cross-modal channel of scene decoding through the sounds of objects within the scenes in the occipitotemporal cortex, which could complement the single-modal channel of scene decoding based on the global scene properties or objects within the scenes.

Identification of Common Thalamocortical Dysconnectivity in Four Major Psychiatric Disorders.

Recent genetic and imaging analyses of large datasets suggested that common biological substrates exist across psychiatric diagnoses. Functional connectivity (FC) abnormalities of thalamocortical circuits were consistently found in patients with schizophrenia but have been less studied in other major psychiatric disorders. This study aimed to examine thalamocortical FC in 4 major psychiatric disorders to identify the common connectivity abnormalities across major psychiatric disorders. This study recruited 100 patients with schizophrenia, 100 patients with bipolar I disorder, 88 patients with bipolar II disorder, 100 patients with major depressive disorder, and 160 healthy controls (HCs). Each participant underwent resting functional magnetic resonance imaging. The thalamus was used to derive FC maps, and group comparisons were made between each patient group and HCs using an independent-sample t test. Conjunction analysis was used to identify the common thalamocortical abnormalities among these 4 psychiatric disorders. The 4 groups of patients shared a similar pattern of thalamocortical dysconnectivity characterized by a decrease in thalamocortical FC with the dorsal anterior cingulate, anterior prefrontal cortex and inferior parietal cortex. The groups also showed an increase in FC with the postcentral gyrus, precentral gyrus, superior temporal cortex, and lateral occipital areas. Further network analysis demonstrated that the frontoparietal regions showing hypoconnectivity belonged to the salience network. Our findings provide FC evidence that supports the common network hypothesis by identifying common thalamocortical dysconnectivities across 4 major psychiatric disorders. The network analysis also supports the cardinal role of salience network abnormalities in major psychiatric disorders.

Value-driven attentional capture in neglect

ObjectiveRecent studies suggest that motivational cues such as rewards may be a powerful determinant of attentional selection, both in healthy subjects and in brain-damaged patients suffering from neglect. However, the exact brain mechanisms underlying these effects and their relation to other well-known attentional systems are still poorly known. MethodsWe designed a visual search paradigm to examine how value-based attentional priority could modulate spatial orienting in patients with pathological biases due to neglect after right hemispheric stroke. Targets were preceded by exogenous valid or invalid spatial cues, in the presence or absence of distractors that were associated with high reward values subsequent to an initial reinforcement training phase. ResultsWe found that the learned reward value of distractors interfered with spatial reorienting toward the left (neglected) side when neglect patients were invalidly cued to the right side. Moreover, the presence of reward-associated distractors in the contralesional field interfered most with the detection of task-relevant targets on the same side, and this interference was exaggerated with more severe neglect. Voxelwise anatomical lesion analysis indicated that damage to the right angular gyrus, as well as lateral occipital and inferior temporal areas of the right hemisphere, were associated with stronger value-driven attentional effects. ConclusionsVisual stimuli previously associated with rewards receive higher attentional priority during visual search despite pathological spatial biases due to neglect, and thus interfere with orienting to contralesional targets, presumably by competing with top-down mechanisms controlling exogenous spatial attention. Reward signals may bias neural activity evoked by visual stimuli, independent of conscious control, through a common priority map integrating several different attentional influences. These results do not only provide novel insights to link spatial orienting and motivational signals within current models of attention, but also open new perspectives that may usefully be exploited for neurological rehabilitation strategies in patients suffering from attentional deficits and neglect.