Integration of exteroceptive and interoceptive information within the hippocampus: a computational study

Caregivers' Attention Toward, and Response to, Their Child's Interoceptive Hunger and Thirst Cues

People can use their internal state to determine if they are hungry or thirsty. Although the meaning of some interoceptive cues may be innate (e.g., pain), it is possible that others-including those for hunger and thirst-are acquired. There has been little exploration of this idea in humans. Consequently, we conducted a survey among child caregivers to determine if the basic conditions necessary for interoceptive learning were present. Two-hundred and thirty-five caregivers of children aged 1-12 years were asked if they had recently noticed stomach rumbling, hunger-related irritability, and a dry mouth in their child. They were also asked how they would respond. The impact of several moderating variables, especially caregiver beliefs about the causes of hunger, fullness, and thirst, was also explored. Fifteen percent of caregivers had recently noticed stomach rumbling in their child, 28% hunger-related irritability, and 14% a dry mouth. Forty-four percent of caregivers had noticed at least one of these three cues. Noticing hunger cues was significantly moderated by caregiver beliefs about their cause, by child age, and in one case by temporal context (around vs. outside mealtimes). Key caregiver responses were providing the need (e.g., offer food) and/or asking the child if they had a need (e.g., hungry?). Each type of response could potentially support a different form of interoceptive learning. In conclusion, we suggest the necessary conditions for children to learn interoceptive hunger and thirst cues, are present in many caregiver-offspring dyads.

Sensory processing across eating disorders: A systematic review and meta-analysis of self-report inventories

OBJECTIVE

This review investigated the extant literature regarding the relationship between eating disorder diagnoses and sensory processing as measured by validated and reliable self-report inventories. Increasing evidence highlights the role of sensory processing in cognitive functions. Sensory processing is implicated in mental-ill health, including eating disorders (ED) and body image disturbances. However, the pathophysiological underpinnings of sensory processing, encompassing exteroception and interoception, in relation to ED remain underexplored.

METHOD

We included studies involving participants aged 15 years or older with an eating disorder diagnosis confirmed by semi-structured or structured interviews. We further limited inclusion to articles using validated and reliable self-report instruments to measure sensory processing. Our meta-analysis focused on studies using the interoceptive awareness subscale from the second version of the Eating Disorder Inventory. We used the Critical Appraisal checklist for quasi-experimental studies to assess the quality of included articles.

RESULTS

There were 19 studies that met our inclusion criteria. Most studies showed moderate-to-high quality. Anorexia nervosa (AN) and bulimia nervosa (BN) were associated with heightened exteroception. Moreover, people with AN reported a heightened sense of taste compared to those with BN. Our meta-analysis comprising 10 studies, 19 samples, and 6382 participants revealed that AN (binge-purge subtype) and BN were associated with increased interoceptive difficulties compared to AN (restrictive subtype) or binge-eating disorder.

DISCUSSION

Overall, this review emphasizes the need for a deeper investigation into sensory processing, spanning both exteroception and interoception, in relation to ED. This may prove important for individualizing person-centered care.

PUBLIC SIGNIFICANCE

How people process internal, for example, hunger, and external, for example, taste and sensations is known to influence cognition and mental-ill health, including ED and body image disturbances. However, the ways in which sensory processing may contribute to ED are incompletely understood. We found that individuals with AN or BN experienced heightened exteroception, while people with an eating disorder characterized by purging reported increased interoceptive difficulties. These patterns could inform the development of more personalized treatments.

Neurophysiological changes associated with vibroacoustically-augmented breath-focused mindfulness for dissociation: targeting interoception and attention

BACKGROUND

Dissociative symptoms can emerge after trauma and interfere with attentional control and interoception; disruptions to these processes are barriers to mind-body interventions such as breath-focused mindfulness (BFM). To overcome these barriers, we tested the use of an exteroceptive augmentation to BFM, using vibrations equivalent to the amplitude of the auditory waveform of the actual breath, delivered via a wearable subwoofer in real time (VBFM). We tested whether this device enhanced interoceptive processes, attentional control and autonomic regulation in trauma-exposed women with dissociative symptoms.

METHODS

65 women, majority (82%) Black American, aged 18-65 completed self-report measures of interoception and 6 BFM sessions, during which electrocardiographic recordings were taken to derive high-frequency heart rate variability (HRV) estimates. A subset (n = 31) of participants completed functional MRI at pre- and post-intervention, during which they were administered an affective attentional control task.

RESULTS

Compared to those who received BFM only, women who received VBFM demonstrated greater increases in interoception, particularly their ability to trust body signals, increased sustained attention, as well as increased connectivity between nodes of emotion processing and interoceptive networks. Intervention condition moderated the relationship between interoception change and dissociation change, as well as the relationship between dissociation and HRV change.

CONCLUSIONS

Vibration feedback during breath focus yielded greater improvements in interoception, sustained attention and increased connectivity of emotion processing and interoceptive networks. Augmenting BFM with vibration appears to have considerable effects on interoception, attention and autonomic regulation; it could be used as a monotherapy or to address trauma treatment barriers.

Breast Cancer: How Hippotherapy Bridges the Gap between Healing and Recovery-A Randomized Controlled Clinical Trial

BACKGROUND

Breast cancer is the most diagnosed women's cancer, and has a high survival rate. Despite great progress in detection and treatment, life reconstruction requires comprehensive cross-sectoral approaches between different disciplines and deeper consideration of the patient's challenges. Hippotherapy is an emerging specialized rehabilitation approach, performed by accredited health professionals and equine specialists, on specially trained horses via their movement, activating major paths for physical, mental, psychic and social reinforcement, and is synergistic to rehabilitative and supportive care.

METHODS

We conducted a randomized open, prospective, two-armed, controlled trial on the effectiveness of hippotherapy versus conventional supportive care on adult women with a diagnosis of breast cancer, after the period of primary treatment (surgery, chemotherapy, radiotherapy). The 6-month program included, in the treated group, an initial 1-week daily hippotherapy session, followed by three short 2-day sessions with an interval of 2 months between each, where the patients received conventional supportive care. The control group received 6 months of conventional supportive care. The primary end point was quality of life. Cognitive performances, fatigue, anxiety, depression, and body image were the secondary end points. Measurements were done through self-reported questionnaires.

RESULTS

We observed statistical differences in the evolution of the measured parameters over time between the two groups. The hippotherapy group showed a much faster, favorable and continuous improvement until the end of the program for each function assessed. The most striking improvements were observed in global quality of life, and fatigue, while breast cancer-specific quality of life, cognitive performance, anxiety and depression and body image showed a less marked but still statistically significant difference at the final post-treatment evaluation.

CONCLUSIONS

We demonstrate the therapeutic relevance of hippotherapy, a one-health approach, as a key initial stage after cancer diagnosis and treatment to foster recovery. Furthermore, hippotherapy has a strong impact on cancer treatments' efficiency and reconstruction of patient's life and ecosystem. This work reveals a layer of complexity that needs to be broadly considered.

TRIAL REGISTRATION

ClincalTrials.gov NCT04350398 accessed on 1 January 2022. Registered 17 April 2020, retrospectively registered; French Clinical Trials in Cancer Register RECF3818. Registered 18 March 2019, retrospectively registered.

The contemporary model of vertebral column joint dysfunction and impact of high-velocity, low-amplitude controlled vertebral thrusts on neuromuscular function

Purpose

There is growing evidence that vertebral column function and dysfunction play a vital role in neuromuscular control. This invited review summarises the evidence about how vertebral column dysfunction, known as a central segmental motor control (CSMC) problem, alters neuromuscular function and how spinal adjustments (high-velocity, low-amplitude or HVLA thrusts directed at a CSMC problem) and spinal manipulation (HVLA thrusts directed at segments of the vertebral column that may not have clinical indicators of a CSMC problem) alters neuromuscular function.

Methods

The current review elucidates the peripheral mechanisms by which CSMC problems, the spinal adjustment or spinal manipulation alter the afferent input from the paravertebral tissues. It summarises the contemporary model that provides a biologically plausible explanation for CSMC problems, the manipulable spinal lesion. This review also summarises the contemporary, biologically plausible understanding about how spinal adjustments enable more efficient production of muscular force. The evidence showing how spinal dysfunction, spinal manipulation and spinal adjustments alter central multimodal integration and motor control centres will be covered in a second invited review.

Results

Many studies have shown spinal adjustments increase voluntary force and prevent fatigue, which mainly occurs due to altered supraspinal excitability and multimodal integration. The literature suggests physical injury, pain, inflammation, and acute or chronic physiological or psychological stress can alter the vertebral column’s central neural motor control, leading to a CSMC problem. The many gaps in the literature have been identified, along with suggestions for future studies.

Conclusion

Spinal adjustments of CSMC problems impact motor control in a variety of ways. These include increasing muscle force and preventing fatigue. These changes in neuromuscular function most likely occur due to changes in supraspinal excitability. The current contemporary model of the CSMC problem, and our understanding of the mechanisms of spinal adjustments, provide a biologically plausible explanation for how the vertebral column’s central neural motor control can dysfunction, can lead to a self-perpetuating central segmental motor control problem, and how HVLA spinal adjustments can improve neuromuscular function.

A global framework for a systemic view of brain modeling

The brain is a complex system, due to the heterogeneity of its structure, the diversity of the functions in which it participates and to its reciprocal relationships with the body and the environment. A systemic description of the brain is presented here, as a contribution to developing a brain theory and as a general framework where specific models in computational neuroscience can be integrated and associated with global information flows and cognitive functions. In an enactive view, this framework integrates the fundamental organization of the brain in sensorimotor loops with the internal and the external worlds, answering four fundamental questions (what, why, where and how). Our survival-oriented definition of behavior gives a prominent role to pavlovian and instrumental conditioning, augmented during phylogeny by the specific contribution of other kinds of learning, related to semantic memory in the posterior cortex, episodic memory in the hippocampus and working memory in the frontal cortex. This framework highlights that responses can be prepared in different ways, from pavlovian reflexes and habitual behavior to deliberations for goal-directed planning and reasoning, and explains that these different kinds of responses coexist, collaborate and compete for the control of behavior. It also lays emphasis on the fact that cognition can be described as a dynamical system of interacting memories, some acting to provide information to others, to replace them when they are not efficient enough, or to help for their improvement. Describing the brain as an architecture of learning systems has also strong implications in Machine Learning. Our biologically informed view of pavlovian and instrumental conditioning can be very precious to revisit classical Reinforcement Learning and provide a basis to ensure really autonomous learning.

Hippocampal volume, function, and related molecular activity in anorexia nervosa: A scoping review

INTRODUCTION

Anorexia nervosa (AN) is a serious and persistent eating disorder, characterized by severe dietary restriction and weight loss, with a third of patients developing a  severe-enduring form. The factors contributing to this progression are poorly understood, although there is evidence for impairments in neural structures such as the hippocampus, an area particularly affected by malnutrition and chronic stress.

AREAS COVERED

This study aimed to map the evidence for alterations in hippocampal volume, function, and related molecular activity in anorexia nervosa. PubMed, PsycINFO, and Web of Science were searched for studies related to hippocampal function and integrity using a range of methodologies, such as neuropsychological paradigms, structural and functional magnetic resonance imaging, and analysis of blood components.

EXPERT OPINION

Thirty-nine studies were included in this review. The majority were neuroimaging studies, which found hippocampus-specific volumetric and functional impairments. Neuropsychological studies showed evidence for a specific memory and learning impairments. There was some evidence for molecular abnormalities (e.g. cortisol), although these were few studies. Taken together, our review suggests that the hippocampus might be a particular region of interest when considering neurobiological approaches to understanding AN. These findings warrant further investigation and may lead to novel treatment approaches.

Why Is Aging a Risk Factor for Cognitive Impairment in Parkinson's Disease?-A Resting State fMRI Study

Using resting-state functional MRI (rsfMRI) data of younger and older healthy volunteers and patients with Parkinson's disease (PD) with and without mild cognitive impairment (MCI) and applying two different analytic approaches, we investigated the effects of age, pathology, and cognition on brain connectivity. When comparing rsfMRI connectivity strength of PD patients and older healthy volunteers, reduction between multiple brain regions in PD patients with MCI (PD-MCI) compared with PD patients without MCI (PD-non-MCI) was observed. This group difference was not affected by the number and location of clusters but was reduced when age was included as a covariate. Next, we applied a graph-theory method with a cost-threshold approach to the rsfMRI data from patients with PD with and without MCI as well as groups of younger and older healthy volunteers. We observed decreased hub function (measured by degree and betweenness centrality) mainly in the medial prefrontal cortex (mPFC) in older healthy volunteers compared with younger healthy volunteers. We also found increased hub function in the posterior medial structure (precuneus and the cingulate cortex) in PD-non-MCI patients compared with older healthy volunteers and PD-MCI patients. Hub function in these posterior medial structures was positively correlated with cognitive function in all PD patients. Together these data suggest that overlapping patterns of hub modifications could mediate the effect of age as a risk factor for cognitive decline in PD, including age-related reduction of hub function in the mPFC, and recruitment availability of the posterior medial structure, possibly to compensate for impaired basal ganglia function.

The Possible Role of Neurobeachin in Extinction of Contextual Fear Memory

Established fear memory becomes vulnerable to disruption after memory retrieval and extinction; this labile state is critical for inhibiting the return of fear memory. However, the labile state has a very narrow time window after retrieval, and underlying molecular mechanisms are not well known. To that end, we isolated the hippocampus immediately after fear memory retrieval and performed proteomics. We identified Neurobeachin (NBEA), an autism-related regulator of synaptic protein trafficking, to be upregulated after contextual fear memory retrieval. NBEA protein expression was rapid and transient after fear memory retrieval at the synapse. Nbea mRNA was enriched at the synapses, and the rapid induction of NBEA expression was blocked by inhibition of the mammalian target of rapamycin (mTOR)-dependent signaling pathway. Mice with cornu ammonis 1 (CA1)-specific Nbea shRNA knockdown showed normal fear acquisition and contextual fear memory but impaired extinction, suggesting an important role of Nbea in fear memory extinction processes. Consistently, Nbea heterozygotes showed normal fear acquisition and fear memory recall but showed impairment in extinction. Our data suggest that NBEA is necessary either for induction of memory lability or for the physiological process of memory extinction.