Attention-dependent modulation of cortical taste circuits revealed by granger causality with signal-dependent noise

We show, for the first time, that in cortical areas, for example the insular, orbitofrontal, and lateral prefrontal cortex, there is signal-dependent noise in the fMRI blood-oxygen level dependent (BOLD) time series, with the variance of the noise increasing approximately linearly with the square of the signal. Classical Granger causal models are based on autoregressive models with time invariant covariance structure, and thus do not take this signal-dependent noise into account. To address this limitation, here we describe a Granger causal model with signal-dependent noise, and a novel, likelihood ratio test for causal inferences. We apply this approach to the data from an fMRI study to investigate the source of the top-down attentional control of taste intensity and taste pleasantness processing. The Granger causality with signal-dependent noise analysis reveals effects not identified by classical Granger causal analysis. In particular, there is a top-down effect from the posterior lateral prefrontal cortex to the insular taste cortex during attention to intensity but not to pleasantness, and there is a top-down effect from the anterior and posterior lateral prefrontal cortex to the orbitofrontal cortex during attention to pleasantness but not to intensity. In addition, there is stronger forward effective connectivity from the insular taste cortex to the orbitofrontal cortex during attention to pleasantness than during attention to intensity. These findings indicate the importance of explicitly modeling signal-dependent noise in functional neuroimaging, and reveal some of the processes involved in a biased activation theory of selective attention

The scientific value of tractography: Accuracy vs usefulness

Tractography has emerged as a central tool for mapping the cerebral white matter architecture. However, its scientific value continues to be a subject of debate, given its inherent limitations in anatomical accuracy. This concise communication showcases key points of a debate held at the 2024 Tract-Anat Retreat, addressing the trade-offs between the accuracy and utility of tractography. While tractography remains constrained by limitations related to resolution, sensitivity, and validation, its usefulness and utility in areas such as surgical planning, disorder prediction, and the elucidation of brain development are emphasized. These perspectives highlight the necessity of context-specific interpretation, anatomically informed algorithms, and the continuous refinement of tractography workflows to achieve an optimal balance between accuracy and utility

Development curves of communication and social interaction in individuals with cerebral palsy

Aim: To determine development curves of communication and social interaction from childhood into adulthood for individuals with cerebral palsy (CP). Method: This Pediatric Rehabilitation Research in the Netherlands (PERRIN)-DECADE study longitudinally assessed 421 individuals with CP, aged from 1 to 20 years at baseline, after 13 years (n=121 at follow-up). Communication and social interactions were assessed using the Vineland Adaptive Behavior Scales. We estimated the average maximum performance limit (level) and age at which 90% of the limit was reached (age90) using nonlinear mixed-effects modeling. Results: One-hundred individuals without intellectual disability were aged 21 to 34 years at follow-up (39 females, 61 males) (mean age [SD] 28y 5mo [3y 11mo]). Limits of individuals without intellectual disability, regardless of Gross Motor Function Classification System (GMFCS) level, approached the maximum score and were significantly higher than those of individuals with intellectual disability. Ages90 ranged between 3 and 4 years for receptive communication, 6 and 7 years for expressive communication and interrelationships, 12 and 16 years for written communication, 13 and 16 years for play and leisure, and 14 and 16 years for coping. Twenty-one individuals with intellectual disability were between 21 and 27 years at follow-up (8 females, 13 males) (mean age [SD] 24y 7mo [1y 8mo]). Individuals with intellectual disability in GMFCS level V showed the least favourable development, but variation between individuals with intellectual disability was large. Interpretation: Individuals with CP and without intellectual disability show developmental curves of communication and social interactions similar to typically developing individuals, regardless of their level of motor function. Those with intellectual disability reach lower performance levels and vary largely in individual development. What this paper adds: Communication and social interactions in individuals with cerebral palsy without intellectual disability develop similarly to typically developing individuals. Communication and social interactions of individuals with intellectual disability develop less favourably and show large variation

Pain, fatigue, depressive symptoms and sleep disturbance in young adults with cerebral palsy

Purpose: Investigate pain, fatigue, depressive symptoms and sleep disturbance in young adults with cerebral palsy compared to references. Materials and methods: Young adults with cerebral palsy (n = 97, aged 21-34 years) and age-matched references from the general population (n = 190) rated pain using a numeric rating scale and fatigue, depressive symptoms, sleep disturbance and global health using Patient-Reported Outcomes Measurement Information System (R) short forms. Scores were compared between cerebral palsy subgroups and the reference population. Correlation coefficients and linear regression analyses assessed interrelationships of health issues and associations with global health. Results: Individuals with Gross Motor Function Classification System level I had less pain, fatigue and depressive symptoms, while individuals with levels II and III-V had more pain (53% and 56%, p <0.001) and those with levels III-V more fatigue (39%, p = 0.035) than references (pain: 26%, fatigue: 14%). Pain and fatigue were more interrelated (correlation coefficients: 0.71 vs. 0.41) and stronger associated with global mental health in individuals with cerebral palsy. Conclusions: Young adults with Gross Motor Function Classification System levels II-V report more pain and those with levels III-V report more fatigue than references. Pain and fatigue are highly interrelated and specifically relate to mental health in individuals with cerebral palsy

Comparative quantitative analysis reveals preserved structural connectivity patterns in the human and macaque brain

The macaque brain serves as a model for the human brain, but its suitability is challenged by unique human features, including connectivity reconfigurations, which emerged during primate evolution. We perform a quantitative comparative analysis of the whole brain macroscale structural connectivity of the two species. Our findings suggest that the human and macaque brain as a whole are similarly wired. A region-wise analysis reveals many interspecies similarities of connectivity patterns, but also lack thereof, primarily involving cingulate and parietal regions. We unravel a common structural backbone in both species involving a highly overlapping set of regions. This structural backbone, important for mediating information across the brain, constitutes a feature of the primate brain persevering evolution. Our findings illustrate novel evolutionary aspects at the macroscale connectivity level, including the existence of common topological structures, and offer a quantitative translational bridge between macaque and human research

Human larynx motor cortices coordinate respiration for vocal-motor control.

Vocal flexibility is a hallmark of the human species, most particularly the capacity to speak and sing. This ability is supported in part by the evolution of a direct neural pathway linking the motor cortex to the brainstem nucleus that controls the larynx the primary sound source for communication. Early brain imaging studies demonstrated that larynx motor cortex at the dorsal end of the orofacial division of motor cortex (dLMC) integrated laryngeal and respiratory control, thereby coordinating two major muscular systems that are necessary for vocalization. Neurosurgical studies have since demonstrated the existence of a second larynx motor area at the ventral extent of the orofacial motor division (vLMC) of motor cortex. The vLMC has been presumed to be less relevant to speech motor control, but its functional role remains unknown. We employed a novel ultra-high field (7T) magnetic resonance imaging paradigm that combined singing and whistling simple melodies to localise the larynx motor cortices and test their involvement in respiratory motor control. Surprisingly, whistling activated both 'larynx areas' more strongly than singing despite the reduced involvement of the larynx during whistling. We provide further evidence for the existence of two larynx motor areas in the human brain, and the first evidence that laryngeal-respiratory integration is a shared property of both larynx motor areas. We outline explicit predictions about the descending motor pathways that give these cortical areas access to both the laryngeal and respiratory systems and discuss the implications for the evolution of speech

Autonomy in participation in cerebral palsy from childhood to adulthood

Aim To determine the long-term development of autonomy in participation of individuals with cerebral palsy (CP) without intellectual disability. Method Individuals with CP (n=189, 117 males, 72 females; mean age [SD] 21y 11mo [4y 11mo], range 12-34y); were assessed cross-sectionally (46%) or up to four times (54%), between the ages of 12 and 34 years. Autonomy in participation was classified using phase 3 of the Rotterdam Transition Profile. A logistic generalized estimating equation regression model was used to analyse autonomy in six domains (independent variables: age, Gross Motor Function Classification System [GMFCS] level, and interaction between age and GMFCS level). Proportions of autonomy were compared to references using binomial tests (pIndividuals with cerebral palsy without intellectual disability achieved autonomy in most participation domains. Regarding intimate relationships, they continued to have less experience compared to age-matched references. Development of autonomy was less favourable for individuals in Gross Motor Function Classification System levels III to V.</p

Optimal short-time acquisition schemes in high angular resolution diffusion-weighted imaging

This work investigates the possibilities of applying high-angular-resolution-diffusion-imaging- (HARDI-) based methods in a clinical setting by investigating the performance of non-Gaussian diffusion probability density function (PDF) estimation for a range of b-values and diffusion gradient direction tables. It does so at realistic SNR levels achievable in limited time on a high-performance 3T system for the whole human brain in vivo. We use both computational simulations and in vivo brain scans to quantify the angular resolution of two selected reconstruction methods: Q-ball imaging and the diffusion orientation transform. We propose a new analytical solution to the ODF derived from the DOT. Both techniques are analytical decomposition approaches that require identical acquisition and modest postprocessing times and, given the proposed modifications of the DOT, can be analyzed in a similar fashion. We find that an optimal HARDI protocol given a stringent time constraint (48). Our findings generalize to other methods and additional improvements in MR acquisition techniques

Development of work participation in young adults with cerebral palsy: A longitudinal study

Objective: To document the development of work participation in young adults with cerebral palsy who are transitioning into adulthood, examine associated characteristics, and investigate work limitations and barriers among employed persons.Design: Observational longitudinal cohort study.Subjects: Seventy-four young adults with cerebral palsy of average intelligence, aged 16-20 years at baseline.Methods: Work participation in 3 categories (employed, unemployed, studying) was assessed at baseline, 2-year and 4-year follow-ups using structured interviews. At 4-year follow-up, associations of work participation with demographic and clinical characteristics were examined using multinomial logistic regression. Work limitations and barriers among employed persons were evaluated using questionnaires.Results: From age range 16-20 years to age range 20-24 years the proportions of subjects who were employed and unemployed increased from 12% to 49% and 3% to 17%, respectively; the proportion who were students decreased from 85% to 34%. In the age range 20-24 years, the employment rate of young adults with cerebral palsy was lower and the unemployment rate higher, than that of the general population. A lower level of gross motor function and younger age were associated with unemployment. Employed persons experienced few work limitations; 28% experienced situational or health barriers.Conclusion: Young adults with cerebral palsy and average intelligence are at risk of experiencing unfavourable developments in work participation. Rehabilitation services should offer support to prevent unemployment and occupational disability