Neural Evidence of Hierarchical Cognitive Control during Haptic Processing: An fMRI Study

Interacting with our immediate surroundings requires constant manipulation of objects. Dexterous manipulation depends on comparison between actual and predicted sensory input, with these predictions calculated by means of lower- and higher-order corollary discharge signals. However, there is still scarce knowledge about the hierarchy in the neural architecture supporting haptic monitoring during manipulation. The present study aimed to assess this issue focusing on the cross talk between lower- order sensory and higher-order associative regions. We used functional magnetic resonance imaging in humans during a haptic discrimination task in which participants had to judge whether a touched shape or texture corresponded to an expected stimulus whose name was previously presented. Specialized haptic regions identified with an independent localizer task did not differ between expected and unexpected conditions, suggesting their lack of involvement in tactile monitoring. When presented stimuli did not match previous expectations, the left supramarginal gyrus (SMG), middle temporal, and medial prefrontal cortices were activated regardless of the nature of the haptic mismatch (shape/texture). The left primary somatosensory area (SI) responded differently to unexpected shapes and textures in line with a specialized detection of haptic mismatch. Importantly, connectivity analyses revealed that the left SMG and SI were more functionally coupled during unexpected trials, emphasizing their interaction. The results point for the first time to a hierarchical organization in the neural substrates underlying haptic monitoring during manipulation with the SMG as a higher-order hub comparing actual and predicted somatosensory input, and SI as a lower- order site involved in the detection of more specialized haptic mismatch

Tactile expectancy modulates occipital alpha oscillations in early blindness

Alpha oscillatory activity is thought to contribute to visual expectancy through the engagement of task-relevant occipital regions. In early blindness, occipital alpha oscillations are systematically reduced, suggesting that occipital alpha depends on visual experience. However, it remains possible that alpha activity could serve expectancy in non-visual modalities in blind people, especially considering that previous research has shown the recruitment of the occipital cortex for non-visual processing. To test this idea, we used electroencephalography to examine whether alpha oscillations reflected a differential recruitment of task-relevant regions between expected and unexpected conditions in two haptic tasks (texture and shape discrimination). As expected, sensor-level analyses showed that alpha suppression in parieto-occipital sites was significantly reduced in early blind individuals compared with sighted participants. The source reconstruction analysis revealed that group differences originated in the middle occipital cortex. In that region, expected trials evoked higher alpha desynchronization than unexpected trials in the early blind group only. Our results support the role of alpha rhythms in the recruitment of occipital areas in early blind participants, and for the first time we show that although posterior alpha activity is reduced in blindness, it remains sensitive to expectancy factors. Our findings therefore suggest that occipital alpha activity is involved in tactile expectancy in blind individuals, serving a similar function to visual anticipation in sighted populations but switched to the tactile modality. Altogether, our results indicate that expectancy-dependent modulation of alpha oscillatory activity does not depend on visual experience. Significance statement: Are posterior alpha oscillations and their role in expectancy and anticipation dependent on visual experience? Our results show that tactile expectancy can modulate posterior alpha activity in blind (but not sighted) individuals through the engagement of occipital regions, suggesting that in early blindness, alpha oscillations maintain their proposed role in visual anticipation but subserve tactile processing. Our findings bring a new understanding of the role that alpha oscillatory activity plays in blindness, contrasting with the view that alpha activity is task unspecific in blind populations

Performance monitoring in lung cancer patients pre- and post-chemotherapy using fine-grained electrophysiological measures

No previous event-related potentials (ERPs) study has explored the error-related negativity (ERN) - an ERP component indexing performance monitoring - associated to cancer and chemotherapy-induced cognitive impairment in a lung cancer population. The aim of this study was to examine differences in performance monitoring in a small-cell lung cancer group (SCLC, C+) 1-month following chemotherapy and two control groups: a non-small cell lung cancer patient group (NSCLC, C-) prior to chemotherapy and a healthy control group (HC). Seventeen SCLC (C+) underwent a neuropsychological assessment and an ERP study using a flanker and a stop-signal paradigm. This group was compared to fifteen age-, gender-and education-matched NSCLC (C-) and eighteen HC. Between 20 and 30% of patients in both lung cancer groups (C+ and C-) met criteria for cognitive impairment. Concerning ERPs, lung cancer patients showed lower overall hit rate and a severe ERN amplitude reduction compared to HC. Lung cancer patients exhibited an abnormal pattern of performance monitoring thus suggesting that chemotherapy and especially cancer itself, may contribute to cognitive deterioration. ERN appeared as an objective laboratory tool sensitive to cognitive dysfunction in cancer population

Structural and Functional Network-Level Reorganization in the Coding of Auditory Motion Directions and Sound Source Locations in the Absence of Vision

Epub 2022 May 2hMT+/V5 is a region in the middle occipitotemporal cortex that responds preferentially to visual motion in sighted people. In cases of early visual deprivation, hMT+/V5 enhances its response to moving sounds. Whether hMT+/V5 contains information about motion directions and whether the functional enhancement observed in the blind is motion specific, or also involves sound source location, remains unsolved. Moreover, the impact of this cross-modal reorganization of hMT+/V5 on the regions typically supporting auditory motion processing, like the human planum temporale (hPT), remains equivocal. We used a combined functional and diffusion-weighted MRI approach and individual in-ear recordings to study the impact of early blindness on the brain networks supporting spatial hearing in male and female humans. Whole-brain univariate analysis revealed that the anterior portion of hMT+/V5 responded to moving sounds in sighted and blind people, while the posterior portion was selective to moving sounds only in blind participants. Multivariate decoding analysis revealed that the presence of motion direction and sound position information was higher in hMT+/V5 and lower in hPT in the blind group. While both groups showed axis-of-motion organization in hMT+/V5 and hPT, this organization was reduced in the hPT of blind people. Diffusion-weighted MRI revealed that the strength of hMT+/V5-hPT connectivity did not differ between groups, whereas the microstructure of the connections was altered by blindness. Our results suggest that the axis-of-motion organization of hMT+/V5 does not depend on visual experience, but that congenital blindness alters the response properties of occipitotemporal networks supporting spatial hearing in the sighted.SIGNIFICANCE STATEMENT Spatial hearing helps living organisms navigate their environment. This is certainly even more true in people born blind. How does blindness affect the brain network supporting auditory motion and sound source location? Our results show that the presence of motion direction and sound position information was higher in hMT+/V5 and lower in human planum temporale in blind relative to sighted people; and that this functional reorganization is accompanied by microstructural (but not macrostructural) alterations in their connections. These findings suggest that blindness alters cross-modal responses between connected areas that share the same computational goals.The project was funded in part by a European Research Council starting grant MADVIS (Project 337573) awarded to O.C., the Belgian Excellence of Science (EOS) program (Project 30991544) awarded to O.C., a Flagship ERA-NET grant SoundSight (FRS-FNRS PINT-MULTI R.8008.19) awarded to O.C., and by the European Union Horizon 2020 research and innovation program under the Marie Skłodowska-Curie Grant Agreement No. 701250 awarded to V.O. Computational resources have been provided by the supercomputing facilities of the Université catholique de Louvain (CISM/UCL) and the Consortium des Équipements de Calcul Intensif en Fédération Wallonie Bruxelles (CÉCI) funded by the Fond de la Recherche Scientifique de Belgique (F.R.S.-FNRS) under convention 2.5020.11 and by the Walloon Region. A.G.-A. is supported by the Wallonie Bruxelles International Excellence Fellowship and the FSR Incoming PostDoc Fellowship by Université Catholique de Louvain. O.C. is a research associate, C.B. is postdoctoral researcher, and M.R. is a research fellow at the Fond National de la Recherche Scientifique de Belgique (FRS-FNRS)

Direct Structural Connection between Auditory-temporal and Visual-occipital motion selective regions

In humans, the occipital middle-temporal region (investigated for the first time in humans the existence of direct white matter connections hMT+/V5) specializes in the processing of visual motion, while the Planum Temporale (hPT) specializes in auditory motion processing. It has been hypothesized that these regions might communicate directly to achieve fast and optimal exchange of multisensory motion information. In this study, we investigated for the first time in humans (male and female) the existence of direct white matter connections between visual and auditory motion-selective regions using a combined functional- and diffusion-MRI approach. We found reliable evidence supporting the existence of direct white matter connections between individually and functionally defined hMT+/V5 and hPT. We show that projections between hMT+/V5 and hPT do not overlap with large white matter bundles such as the Inferior Longitudinal Fasciculus (ILF) nor the Inferior Frontal Occipital Fasciculus (IFOF). Moreover, we did not find evidence for the existence of reciprocal projections between the face fusiform area and hPT, supporting the functional specificity of hMT+/V5 – hPT connections. Finally, evidence supporting the existence of hMT+/V5 – hPT connections was corroborated in a large sample of participants (n=114) from the human connectome project. Altogether, this study provides first evidence supporting the existence of direct occipito-temporal projections between hMT+/V5 and hPT which may support the exchange of motion information between functionally specialized auditory and visual regions and that we propose to name the middle (or motion) occipito-temporal track (MOTT)

Direct Structural Connection between Auditory-temporal and Visual-occipital motion selective regions

Perceiving and integrating motion signals across sensory systems is a crucial perceptual skill for optimal interaction with a multisensory environment. In primates, including humans, the middle-temporal region (hereafter, hMT+/V5) specializes in processing visual motion signals, while the Planum Temporale (hereafter, PT) specializes for auditory motion processing. It has been hypothesized that these regions can communicate directly to achieve fast and optimal multisensory integration of motion signals. However, the existence of direct anatomical connections between these regions remains unexplored. We therefore evaluated the presence of anatomical connections between the hMT+/V5 and the PT in fifteen healthy individuals. Each participant was first involved in an auditory and visual motion localizer in order to define PT and hMT+/V5 functionally. Using diffusion imaging data and conducting probabilistic tractography, we reconstructed white matter tracts between individually defined PT and hMT+/V5. We found reliable connections between hMT+/V5 and PT in both hemispheres in 15 out of 15 individuals, suggesting the existence of a direct pathway between these visual and auditory selective regions. Our findings have important implications for the understanding of the multisensory nature of motion processing, as this connection might represent the structural scaffolding underlying the auditory and tactile responses observed in hMT+/V5