Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

Emotion-related states encompass a wide range of affective and behavioral dimensions, including anxiety, fear, pleasure, and aversion, whereas motivation refers to internal drives that energize goal-directed behaviors such as feeding, reward seeking, or avoidance. These states are thought to arise from the brain’s integration of exteroceptive inputs, interoceptive signals reflecting bodily states, and prior experiences. Recent studies have increasingly highlighted the critical role of gut-to-brain communication, particularly vagal and other interoceptive pathways, in shaping emotion-related and motivational behaviors. In parallel, advances in genetic manipulation techniques have enabled the identification of neuronal circuits innervating the gastrointestinal tract and have provided new insights into their links with affective-like behavior. A better understanding of these mechanisms will be essential for elucidating how gastrointestinal-derived signals contribute to emotion-related states and how they are represented and processed in the brain. In this review, we discuss recent advances in gut-to-brain neural pathways, with a particular focus on vagal afferent and interoceptive mechanisms, while also considering spinal afferent pathways and ENS-related mechanisms that may contribute to emotion-related behavioral regulation.

DOI： 10.3389/fnsys.2026.1855213

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.physbeh.2026.115398

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

ABSTRACT

The locus coeruleus (LC) neurons send extensive projections to the somatosensory cortex and release noradrenaline (NA) at synaptic terminals, which is thought to regulate the activation of sensory‐related cells by acting on three types of receptors (α1, α2 and β). Although previous studies have examined the effects of LC stimulation on single‐unit sensory neurons, their impact on somatosensory evoked potentials (SEPs) and their temporal variations, as well as the specific roles of NA receptors, remain unclear. Herein, we investigated how SEPs are modulated by tonic LC stimulation at physiological frequencies (0.1, 1 and 4 Hz) and identified the receptors involved in these changes. Forepaw stimulation‐induced amplitudes in SEP were enhanced in response to 1 Hz stimulation of the LC but not in response to 0.1 and 4 Hz stimulation. Interestingly, the enhancement of SEPs after LC stimulation persisted for tens of minutes following the cessation of stimulation. Optical imaging using a voltage‐sensitive dye showed an increase in the depolarizing response in the somatosensory cortex after 1 Hz stimulation. Prazosin (α1 receptor antagonist) and propranolol (β receptor antagonist) inhibited SEP enhancement following 1 Hz LC stimulation, whereas yohimbine (α2 receptor antagonist) had no effect. This suggests that the enhancement in SEP observed is primarily mediated by the activation of cortical excitatory α1 and β receptors. These findings provide insight into the impact of the NA system on sensory information processing and the pathophysiology of sensory disorders related to the disruption of the NA system.

DOI： 10.1111/ejn.70020

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Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

The relationship between the morphological characteristics of the infrapatellar fat pad (IFP) and joint deformity has yet to be fully elucidated. Therefore, the purpose of this study was to clarify the morphological characteristics of the IFP and to identify the relationships between morphological characteristics of the IFP and degenerative grade of the articular surface of the patella. This investigation examined 41 legs from 25 Japanese cadavers. The IFP length, width, and volume were measured. It was categorized into three types: Type I, IFP proximal located on medial and lateral sides of the patella; Type II, the IFP proximal only located medially; and Type III, absence of the IFP proximal. Articular surfaces were graded as macroscopically intact or mildly altered (Grade I), moderately (Grade II), or severely (Grade III). Grade III was significantly more frequent than Grades I or II in Type III. IFP volume was significantly larger in Type I than in Types II or III. A negative correlation was found between the degenerative grade of the articular surface of the patella and IFP volume. It was suggested that a relationship between the degenerative grade of the articular surface of the patella and the IFP volume.

DOI： 10.1038/s41598-022-12859-1

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Other Link： https://www.nature.com/articles/s41598-022-12859-1

Publishing type：Research paper (scientific journal)   Publisher：SAGE Publications  

Background:

Thiel cadavers have been reported to have lifelike flexibility and mechanical properties, but whether they are useful for measurement of the ulnohumeral joint space (JS) is unclear. The contributions of the third and fourth digits and the second and fifth digits of the flexor digitorum superficialis (FDS) to elbow valgus stability are also unknown.

Purpose:

To (1) clarify whether Thiel cadavers can be used for JS measurement on ultrasound and (2) identify the contributions to valgus stability of the third and fourth digits and the second and fifth digits of the FDS.

Study Design:

Descriptive laboratory study.

Methods:

In experiment 1 (12 elbows from human volunteers and 12 elbows from Thiel cadavers), valgus stress was increased gradually from 0 to 30 to 60 N, and the JS was compared on ultrasound between groups at each load. In experiment 2 (13 elbows from Thiel cadavers), specimens were divided into 2 groups, and the JS was measured for group 1 with the FDS intact, with tendinous insertions of the third and fourth digits cut (3/4-cut state), and with tendinous insertions of all fingers cut (all-cut state); and for group 2 at intact FDS, with tendinous insertions of the second and fifth digits cut (2/5-cut state), and at all-cut.

Results:

In experiment 1, the rate of change of the JS increased significantly with elbow valgus stress in both humans and Thiel cadavers, with no significant difference between groups. In experiment 2, the JS was significantly greater in the 3/4- and 2/5-cut states compared with the intact state at both 30 N (Δ _{3/4-cut vs intact} = 0.23 mm [ P = .01]; Δ _{2/5-cut vs intact} = 0.32 mm [ P = .02]) and 60 N (Δ _{3/4-cut vs intact} = 0.33 mm [ P = .002]; Δ _{2/5-cut vs intact} = 0.37 mm [ P = .04]). There was no significant difference in JS measurements between the 3/4- and 2/5-cut states at any load.

Conclusion:

Thiel cadavers showed JS changes similar to those of humans when valgus stress was applied. The third and fourth digits and the second and fifth digits of the FDS were involved in valgus stability, and there was no difference in their respective contributions.

Clinical Relevance:

This study may help in identifying function of the FDS based on structure.

DOI： 10.1177/23259671211026247

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Other Link： https://journals.sagepub.com/doi/full-xml/10.1177/23259671211026247