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Background and Objectives: Psychogenic nonepileptic (functional) seizures (FS) clinically resemble epileptic seizures (ES) with both often preceded by traumatic brain injury (TBI). FS and ES emergence and occurrence after TBI may be linked to aberrant neurobehavioral stress responses. We hypothesized that neural activity signatures in response to a psychosocial stress task would differ between TBI + FS and TBI + ES after controlling for TBI status (TBI-only)., Methods: In the current multicenter study, participants were recruited prospectively from Rhode Island Hospital, Providence Rhode Island Veterans Administration Medical Center, and the University of Alabama at Birmingham Medical Center. Previous diagnoses of TBI, ES, and FS were verified based on data collected from participants, medical chart and record review, and, where indicated, results of EEG and/or video-EEG confirmatory diagnosis. TBI + ES (N = 21) and TBI + FS (N = 21) were matched for age and sex and combined into an initial group (TBI + SZ; N = 42). A TBI-only group (N = 42) was age and sex matched to the TBI with seizures (TBI + SZ) group. All participants completed an fMRI control math task (CMT) and stress math task (SMT) based on the Montreal Imaging Stress Task (MIST)., Results: The TBI + SZ group (n = 24 female) did not differ in mood or anxiety severity compared to TBI-only group (n = 24 female). However, TBI + FS group (n = 11 female) reported greater severity of these symptoms compared to TBI + ES (n = 13 female). The linear mixed effects analysis identified neural responses that differed between TBI-only and TBI + SZ during math performance within the left premotor cortex and during auditory feedback within bilateral prefrontal cortex and hippocampus/amygdala regions. Additionally, neural responses differed between TBI + ES and TBI + FS during math performance within the right dorsolateral prefrontal cortex and bilateral amygdala during auditory feedback within the supplementary motor area. All tests comparing neural stress responses to psychiatric symptom severity failed to reach significance., Discussion: Controlling for TBI and seizure status, these findings implicate specific nodes within frontal, limbic, and sensorimotor networks that may maintain functional neurological symptoms and possibly distinguish FS from ES. This study provides class II evidence of differences in neural responses to psychosocial stress between ES and FS after TBI., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Vasoactive intestinal peptide (VIP)-like immunoreactivity was demonstrated in the lingual salt glands of the estuarine crocodile, Crocodylus porosus. Varicose fibers showing VIP-like immunoreactivity ramified the salt glands, forming a dense network around the basal region of the exocrine cells. Secretions from the lingual salt glands were monitored in hatchling C. porosus. Spontaneous secretory activity was variable, ranging from 0.3 to 5.3 micromol Na 100 g(-0.7) bm hr(-1) (bm, body mass). Administration of a 100-microl bolus of 0.9% NaCl, via a cannulated femoral vein, did not affect the spontaneous secretory rate. However, injection of 100 pmol porcine VIP resulted in a massive increase in secretory activity, reaching a maximum of 58.2 micromol of Na 100 g(-0.7) bm hr(-1). The presence of VIP-like immunoreactivity and the positive secretory effect of administered VIP indicate a potential action of VIP on salt gland activity.