Sensory stimulation and timing behavior

The concentration of glycogen, the major brain energy reserve localized mainly in astrocytes, is generally reported as about 2 or 3 μmol/g, but sometimes as high as 3.9 to 8 μmol/g, in normal rat brain. The authors found high but very different glycogen levels in two recent studies in which glycogen was determined by the routine amyloglucosidase procedure in 0.03N HCl digests either of frozen powders (4.8 to 6 μmol/g) or of ethanol-insoluble fractions (8 to 12 μmol/g). To evaluate the basis for these discrepant results, glycogen was assayed in parallel extracts of the same samples. Glycogen levels in ethanol extracts were twice those in 0.03N HCl digests, suggesting incomplete enzyme inactivation even with very careful thawing. The very high glycogen levels were biologically active and responsive to physiologic and pharmacological challenge. Glycogen levels fell after brief sensory stimulation, and metabolic labeling indicated its turnover under resting conditions. About 95% of the glycogen was degraded under in vitro ischemic conditions, and its “carbon equivalents” recovered mainly as glc, glc-P, and lactate. Resting glycogen stores were reduced by about 50% by chronic inhibition of nitric oxide synthase. Because neurotransmitters are known to stimulate glycogenolysis, stress or sensory activation due to animal handling and tissue-sampling procedures may stimulate glycogenolysis during an experiment, and glycogen lability during tissue sampling and extraction can further reduce glycogen levels. The very high glycogen levels in normal rat brain suggest an unrecognized role for astrocytic energy metabolism during brain activation.

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Effect of Aging, Gender and Sensory Stimulation of TRPV1 Receptors with Capsaicin on Spontaneous Swallowing Frequency in Patients with Oropharyngeal Dysphagia: A Proof-of-Concept Study

Diagnostics ◽

10.3390/diagnostics11030461 ◽

2021 ◽

Vol 11 (3) ◽

pp. 461

Author(s):

Weslania Nascimento ◽

Noemí Tomsen ◽

Saray Acedo ◽

Cristina Campos-Alcantara ◽

Christopher Cabib ◽

...

Keyword(s):

Oropharyngeal Dysphagia ◽

Sensory Stimulation ◽

Age And Gender ◽

Post Stroke ◽

Brainstem Reflex ◽

Trpv1 Receptors ◽

Volume Viscosity ◽

And Gender ◽

Effect Of Age ◽

Stimulation Of

Spontaneous swallowing contributes to airway protection and depends on the activation of brainstem reflex circuits in the central pattern generator (CPG). We studied the effect of age and gender on spontaneous swallowing frequency (SSF) in healthy volunteers and assessed basal SSF and TRPV1 stimulation effect on SSF in patients with post-stroke oropharyngeal dysphagia (OD). The effect of age and gender on SSF was examined on 141 healthy adult volunteers (HV) divided into three groups: GI—18–39 yr, GII—40–59 yr, and GIII—>60 yr. OD was assessed by the Volume–Viscosity Swallowing Test (VVST). The effect of sensory stimulation with capsaicin 10−5 M (TRPV1 agonist) was evaluated in 17 patients with post-stroke OD, using the SSF. SSF was recorded in all participants during 10 min using surface electromyography (sEMG) of the suprahyoid muscles and an omnidirectional accelerometer placed over the cricothyroid cartilage. SSF was significantly reduced in GII (0.73 ± 0.50 swallows/min; p = 0.0385) and GIII (0.50 ± 0.31 swallows/min; p < 0.0001) compared to GI (1.03 ± 0.62 swallows/min), and there was a moderate significant correlation between age and SFF (r = −0.3810; p < 0.0001). No effect of gender on SSF was observed. Capsaicin caused a strong and significant increase in SSF after the TRPV1 stimulation when comparing to basal condition (pre-capsaicin: 0.41 ± 0.32 swallows/min vs post-capsaicin: 0.81 ± 0.51 swallow/min; p = 0.0003). OD in patients with post-stroke OD and acute stimulation with TRPV1 agonists caused a significant increase in SSF, further suggesting the potential role of pharmacological stimulation of sensory pathways as a therapeutic strategy for CPG activation in patients with OD.

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Sensory over-responsivity is related to GABAergic inhibition in thalamocortical circuits

Translational Psychiatry ◽

10.1038/s41398-020-01154-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Emily T. Wood ◽

Kaitlin K. Cummings ◽

Jiwon Jung ◽

Genevieve Patterson ◽

Nana Okada ◽

...

Keyword(s):

Magnetic Resonance ◽

Sensory Information ◽

Network Connectivity ◽

Sensory Stimulation ◽

Autism Spectrum ◽

Future Research ◽

Resonance Spectroscopy ◽

Gamma Aminobutyric Acid ◽

Sensory Stimuli ◽

Brain Responses

AbstractSensory over-responsivity (SOR), extreme sensitivity to or avoidance of sensory stimuli (e.g., scratchy fabrics, loud sounds), is a highly prevalent and impairing feature of neurodevelopmental disorders such as autism spectrum disorders (ASD), anxiety, and ADHD. Previous studies have found overactive brain responses and reduced modulation of thalamocortical connectivity in response to mildly aversive sensory stimulation in ASD. These findings suggest altered thalamic sensory gating which could be associated with an excitatory/inhibitory neurochemical imbalance, but such thalamic neurochemistry has never been examined in relation to SOR. Here we utilized magnetic resonance spectroscopy and resting-state functional magnetic resonance imaging to examine the relationship between thalamic and somatosensory cortex inhibitory (gamma-aminobutyric acid, GABA) and excitatory (glutamate) neurochemicals with the intrinsic functional connectivity of those regions in 35 ASD and 35 typically developing pediatric subjects. Although there were no diagnostic group differences in neurochemical concentrations in either region, within the ASD group, SOR severity correlated negatively with thalamic GABA (r = −0.48, p < 0.05) and positively with somatosensory glutamate (r = 0.68, p < 0.01). Further, in the ASD group, thalamic GABA concentration predicted altered connectivity with regions previously implicated in SOR. These variations in GABA and associated network connectivity in the ASD group highlight the potential role of GABA as a mechanism underlying individual differences in SOR, a major source of phenotypic heterogeneity in ASD. In ASD, abnormalities of the thalamic neurochemical balance could interfere with the thalamic role in integrating, relaying, and inhibiting attention to sensory information. These results have implications for future research and GABA-modulating pharmacologic interventions.

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Rehabilitation of Post Stroke Sensory Dysfunction—A Scoping Review

Journal of Stroke Medicine ◽

10.1177/2516608520984296 ◽

2021 ◽

pp. 251660852098429

Author(s):

Dorcas B. C. Gandhi ◽

Ivy Anne Sebastian ◽

Komal Bhanot

Keyword(s):

Motor Behavior ◽

Sensory Modality ◽

Sensory System ◽

Sensory Stimulation ◽

Current Evidence ◽

Cochrane Library ◽

Post Stroke ◽

Sensory Dysfunction ◽

Electronic Database Search ◽

External Stimuli

Sensory dysfunction is one of the common impairments that occurs post stroke. With sensory changes in all modalities, it also affects the quality of life and incites suicidal thoughts. The article attempts to review and describe the current evidence of various approaches of assessment and rehabilitation for post-stroke sensory dysfunction. After extensive electronic database search across Medline, Embase, EBSCO, and Cochrane library, it generated 2433 results. After screening according to inclusion and exclusion criteria, we included 11 studies. We categorized data based on type of sensory deficits and prevalence, role of sensory system on motor behavior, type of intervention, sensory modality targeted, and dosage of intervention and outcome measures used for rehabilitation. Results found the strong evidence of involvement of primary and secondary motor areas involved in processing and responding to somatosensation, respectively. We divided rehabilitation approaches into sensory stimulation approach and sensory retraining approach focused on using external stimuli and relearning, respectively. However, with varied aims and targeted sensory involvement, the study applicability is affected. Thus, this emerges the need of extensive research in future for evidence-based practice of assessments and rehabilitation on post-stroke sensory rehabilitation.

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Sensory Stimulation in the NICU Environment: Devices, Systems, and Procedures to Protect and Stimulate Premature Babies

Children ◽

10.3390/children8050334 ◽

2021 ◽

Vol 8 (5) ◽

pp. 334

Author(s):

Francesco Massimo Vitale ◽

Gaetano Chirico ◽

Carmen Lentini

Keyword(s):

Music Therapy ◽

Preterm Infants ◽

Noise Pollution ◽

Sensory Stimulation ◽

Normative Values ◽

Control Groups ◽

Beneficial Effects ◽

Stressful Environment ◽

Premature Babies ◽

Systematic Control

Prematurity deprives infants of the prenatal sensory stimulation essential to their correct development; in addition, the stressful environment of the NICU impacts negatively on their growth. The purpose of this review was to investigate the effects of NICU noise pollution on preterm infants and parents. We focused on the systems and projects used to control and modulate sounds, as well as on those special devices and innovative systems used to deliver maternal sounds and vibrations to this population. The results showed beneficial effects on the preterm infants in different areas such as physiological, autonomic, and neurobehavioral development. Although most of these studies highlight positive reactions, there is also a general acknowledgement of the current limits: small and heterogeneous groups, lack of structured variable measurements, systematic control groups, longitudinal studies, and normative values. The mother’s presence is always preferred, but the use of music therapy and the devices analyzed, although not able to replace her presence, aim to soften her absence through familiar and protective stimuli, which is a very powerful aid during the COVID-19 pandemic.

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Diversity of neurovascular coupling dynamics along vascular arbors in layer II/III somatosensory cortex

Communications Biology ◽

10.1038/s42003-021-02382-w ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Ravi L. Rungta ◽

Marc Zuend ◽

Ali-Kemal Aydin ◽

Éric Martineau ◽

Davide Boido ◽

...

Keyword(s):

Cerebral Cortex ◽

Somatosensory Cortex ◽

Cerebral Blood Volume ◽

Transfer Functions ◽

Neurovascular Coupling ◽

Sensory Stimulation ◽

Brain Regions ◽

Blood Velocity ◽

Functional Brain Imaging ◽

Vascular Events

AbstractThe spatial-temporal sequence of cerebral blood flow (CBF), cerebral blood volume (CBV) and blood velocity changes triggered by neuronal activation is critical for understanding functional brain imaging. This sequence follows a stereotypic pattern of changes across different zones of the vasculature in the olfactory bulb, the first relay of olfaction. However, in the cerebral cortex, where most human brain mapping studies are performed, the timing of activity evoked vascular events remains controversial. Here we utilized a single whisker stimulation model to map out functional hyperemia along vascular arbours from layer II/III to the surface of primary somatosensory cortex, in anesthetized and awake Thy1-GCaMP6 mice. We demonstrate that sensory stimulation triggers an increase in blood velocity within the mid-capillary bed and a dilation of upstream large capillaries, and the penetrating and pial arterioles. We report that under physiological stimulation, response onset times are highly variable across compartments of different vascular arbours. Furthermore, generating transfer functions (TFs) between neuronal Ca2+ and vascular dynamics across different brain states demonstrates that anesthesia decelerates neurovascular coupling (NVC). This spatial-temporal pattern of vascular events demonstrates functional diversity not only between different brain regions but also at the level of different vascular arbours within supragranular layers of the cerebral cortex.

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