The Experts below are selected from a list of 44994 Experts worldwide ranked by ideXlab platform
Xiaobin He - One of the best experts on this subject based on the ideXlab platform.
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neural circuits containing olfactory neurons are involved in the prepulse inhibition of the startle reflex in rats
Frontiers in Behavioral Neuroscience, 2015Co-Authors: Zhijian Zhang, Xiaobin He, Ting Zhou, Qiang Zhang, Yuehua Qiao, Fuqiang Xu, Min HuAbstract:Many neuropsychiatric disorders, such as schizophrenia, have been associated with olfactory dysfunction and abnormalities in the prepulse inhibition (PPI) response to a startle reflex. However, whether these two abnormalities could be related is unclear. The present investigations were designed to determine whether theblockage of olfactory Sensory Input by zinc sulfate infusion in the olfactory naris (0.5 ml, 0.17 M, ZnE) can disturb the PPI response. Furthermore, a bilateral microinjection of lidocaine/MK801 in the olfactory bulb (OB) was administered to examine whether the blockage of olfactory Sensory Input could impair the PPI response. To identify the neural projection between olfaction and PPI-related areas, trans-synaptic retrograde tracing with the recombinant pseudorabies virus (PRV) was used. Our results demonstrated that blockage of olfactory Sensory Input could disturb olfactory behavior. In the function studies, we demonstrated that blockage of olfactory Sensory Input could impair the pre-pulse inhibition of the startle response following decreased c-Fos expression in relevant brain regions during the PPI responses. Furthermore, similar and more robust findings indicated that blockage of olfactory Sensory Input by microinjection of lidocaine/MK801 in the OB could impair the PPI response. In the circuit-level studies, we demonstrated that trans-synaptic retrograde tracing with PRV exhibited a large portion of labeled neurons in several regions of the olfactory cortices from the pedunculopontine tegmental nucleus (PPTg). Thus, these data suggest that the olfactory system participates in the PPI regulating fields and plays a role in the pre-pulse inhibition of the startle response in rats.
John A Sweeney - One of the best experts on this subject based on the ideXlab platform.
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neurophysiological hyperresponsivity to Sensory Input in autism spectrum disorders
Journal of Neurodevelopmental Disorders, 2016Co-Authors: Yukari Takarae, Savanna R Sablich, Stormi P White, John A SweeneyAbstract:Atypical Sensory processing is a common clinical observation in autism spectrum disorder (ASD). Neural hyperexcitability has been suggested as the cause for Sensory hypersensitivity, a frequently reported clinical observation in ASD. We examined visual evoked responses to parametric increases in stimulus contrast in order to model neural responsivity of Sensory systems in ASD. Thirteen high-functioning individuals with ASD and 12 typically developing (TD) individuals completed a steady-state visual evoked potential study. Stimuli were vertical circular gratings oscillating at 3.76 Hz at varying contrasts (5, 10, 20,…, 90 % contrast, 10 levels). The average spectral power at the stimulus oscillation frequency was calculated for each contrast level. The magnitude of evoked Sensory responses increased at a significantly greater rate and resulted in disproportionately elevated activation with higher contrasts in the ASD group. Approximately 45 % of ASD participants had rates of response increases greater than any TD participant. This alteration was highly associated with parental reports of these participants’ Sensory difficulties. Greater increases in visual responses over contrast manipulation suggest heightened excitability in the Sensory cortex in ASD participants. Heightened neural excitability was observed in a substantial portion but not all of the ASD participants. This pattern suggests that individuals with higher excitability may constitute a neurobiologically distinct subgroup requiring individualized treatment interventions.
John C Rothwell - One of the best experts on this subject based on the ideXlab platform.
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transcallosal sensorimotor integration effects of Sensory Input on cortical projections to the contralateral hand
Clinical Neurophysiology, 2006Co-Authors: Orlando B C Swayne, John C Rothwell, Karin RosenkranzAbstract:Abstract Objective Low amplitude vibration of forearm or hand muscles predominantly activates proprioceptive Inputs that influence corticospinal projections in a focal manner, increasing output to the stimulated muscle while reducing output to neighbouring muscles. Modulation of contralateral forearm muscles by vibration has also been reported on one occasion. The aim of the current investigation was to investigate the effects of proprioceptive Input from a hand muscle on corticospinal excitability, intracortical inhibition (SICI) and interhemispheric inhibition (IHI) targeting the homologous contralateral muscle. Methods Transcranial Magnetic Stimulation (TMS) was delivered to the left cortical hand area of 10 healthy subjects and surface electromyography (EMG) recordings taken from the right First Dorsal Interosseus (FDI) and Abductor Digiti Minimi (ADM). The effect of low amplitude vibration of the left FDI on MEP amplitudes, SICI and IHI targeting the right hand was assessed. Results Vibration of the left FDI caused a significant reduction in MEP amplitudes in the homologous right FDI but not in the right ADM. SICI and IHI targeting both muscles were also significantly increased. Conclusions We conclude that proprioceptive Input from a hand muscle reduces the corticospinal excitability of the contralateral homologous muscle. The increases in SICI and IHI suggest that at least some of this effect occurs in the cortex ipsilateral to the stimulus and this may be mediated via transcallosal fibres. Significance These results suggest that Sensory Input can modulate excitability in both motor cortices simultaneously, as well as the relationship between them. Interventions which modulate this transcallosal relationship may become useful in disorders where abnormal IHI is a potential therapeutic target.
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the effect of Sensory Input and attention on the sensorimotor organization of the hand area of the human motor cortex
The Journal of Physiology, 2004Co-Authors: Karin Rosenkranz, John C RothwellAbstract:Sensory Input can remodel representations in the Sensory cortex, and this effect is heavily influenced by attention to the stimulus. Here we ask whether pure Sensory Input can also influence the spatial distribution of Sensory effects on motor cortical hand area (sensorimotor organization) and whether this is modulated by attention. Sensorimotor organization was tested by applying short (1.5 s) periods of low amplitude vibration to single intrinsic hand muscles and measuring motor cortex excitability with transcranial magnetic stimulation (TMS). In healthy subjects, sensorimotor organization in the hand is focal, with Input from one hand muscle increasing motor-evoked potentials (MEPs), decreasing short and increasing long-interval intracortical inhibition (SICI and LICI) in the vibrated muscle (‘homotopic’ effects) and having opposite effects on neighbouring muscles (‘heterotopic’ effects). Here we show that a 15 min intervention of vibration applied simultaneously to two hand muscles can lead to long-term (> 30 min) changes in the spatial pattern of sensorimotor interaction. The amount and direction of the effects depended on the subject's attention during the intervention: if subjects attended to both muscles when they were receiving simultaneous vibration, subsequent short-term vibration applied to one of them produced ‘homotopic’ effects on both muscles. ‘Heterotopic’ effects on a muscle not vibrated during the intervention were unaffected. If subjects did not attend to simultaneous vibration, subsequent short-term vibration of the muscles involved in the intervention no longer had any effect on them although the ‘heterotopic’ effects on a muscle not involved in the intervention were unchanged. We conclude that a 15 min period of pure Sensory Input can remodel the way that subsequent Sensory Inputs interact with motor output, that the effects are specific for the motor output to muscles involved in the intervention and that they are modulated by the subject's attention.
Karin Rosenkranz - One of the best experts on this subject based on the ideXlab platform.
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transcallosal sensorimotor integration effects of Sensory Input on cortical projections to the contralateral hand
Clinical Neurophysiology, 2006Co-Authors: Orlando B C Swayne, John C Rothwell, Karin RosenkranzAbstract:Abstract Objective Low amplitude vibration of forearm or hand muscles predominantly activates proprioceptive Inputs that influence corticospinal projections in a focal manner, increasing output to the stimulated muscle while reducing output to neighbouring muscles. Modulation of contralateral forearm muscles by vibration has also been reported on one occasion. The aim of the current investigation was to investigate the effects of proprioceptive Input from a hand muscle on corticospinal excitability, intracortical inhibition (SICI) and interhemispheric inhibition (IHI) targeting the homologous contralateral muscle. Methods Transcranial Magnetic Stimulation (TMS) was delivered to the left cortical hand area of 10 healthy subjects and surface electromyography (EMG) recordings taken from the right First Dorsal Interosseus (FDI) and Abductor Digiti Minimi (ADM). The effect of low amplitude vibration of the left FDI on MEP amplitudes, SICI and IHI targeting the right hand was assessed. Results Vibration of the left FDI caused a significant reduction in MEP amplitudes in the homologous right FDI but not in the right ADM. SICI and IHI targeting both muscles were also significantly increased. Conclusions We conclude that proprioceptive Input from a hand muscle reduces the corticospinal excitability of the contralateral homologous muscle. The increases in SICI and IHI suggest that at least some of this effect occurs in the cortex ipsilateral to the stimulus and this may be mediated via transcallosal fibres. Significance These results suggest that Sensory Input can modulate excitability in both motor cortices simultaneously, as well as the relationship between them. Interventions which modulate this transcallosal relationship may become useful in disorders where abnormal IHI is a potential therapeutic target.
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the effect of Sensory Input and attention on the sensorimotor organization of the hand area of the human motor cortex
The Journal of Physiology, 2004Co-Authors: Karin Rosenkranz, John C RothwellAbstract:Sensory Input can remodel representations in the Sensory cortex, and this effect is heavily influenced by attention to the stimulus. Here we ask whether pure Sensory Input can also influence the spatial distribution of Sensory effects on motor cortical hand area (sensorimotor organization) and whether this is modulated by attention. Sensorimotor organization was tested by applying short (1.5 s) periods of low amplitude vibration to single intrinsic hand muscles and measuring motor cortex excitability with transcranial magnetic stimulation (TMS). In healthy subjects, sensorimotor organization in the hand is focal, with Input from one hand muscle increasing motor-evoked potentials (MEPs), decreasing short and increasing long-interval intracortical inhibition (SICI and LICI) in the vibrated muscle (‘homotopic’ effects) and having opposite effects on neighbouring muscles (‘heterotopic’ effects). Here we show that a 15 min intervention of vibration applied simultaneously to two hand muscles can lead to long-term (> 30 min) changes in the spatial pattern of sensorimotor interaction. The amount and direction of the effects depended on the subject's attention during the intervention: if subjects attended to both muscles when they were receiving simultaneous vibration, subsequent short-term vibration applied to one of them produced ‘homotopic’ effects on both muscles. ‘Heterotopic’ effects on a muscle not vibrated during the intervention were unaffected. If subjects did not attend to simultaneous vibration, subsequent short-term vibration of the muscles involved in the intervention no longer had any effect on them although the ‘heterotopic’ effects on a muscle not involved in the intervention were unchanged. We conclude that a 15 min period of pure Sensory Input can remodel the way that subsequent Sensory Inputs interact with motor output, that the effects are specific for the motor output to muscles involved in the intervention and that they are modulated by the subject's attention.
Matt Wachowiak - One of the best experts on this subject based on the ideXlab platform.
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in vivo modulation of Sensory Input to the olfactory bulb by tonic and activity dependent presynaptic inhibition of receptor neurons
The Journal of Neuroscience, 2008Co-Authors: Nicolas Pirez, Matt WachowiakAbstract:The first reorganization of odor representations in the nervous system occurs at the synapse between olfactory receptor neurons and second-order neurons in olfactory bulb glomeruli. Signal transmission at this synapse is modulated presynaptically by several mechanisms, a major one being mediated by GABAB receptors, which suppress presynaptic calcium influx and subsequent transmitter release from the receptor neuron terminal. Here, we imaged stimulus-evoked calcium influx into the receptor neuron terminal in anesthetized mice and used odorant and electrical stimulation combined with in vivo pharmacology to characterize the functional determinants of GABAB-mediated presynaptic inhibition and to test hypotheses on the role of this inhibition in olfactory processing. As expected from previous studies, blocking presynaptic GABAB receptors in vivo increased odorant-evoked presynaptic calcium signals, confirming that GABAB-mediated inhibition modulates the strength of receptor Inputs. Surprisingly, we found that the strength of this inhibition was affected little by the nature of the Input, being independent of the spatial distribution of activated glomeruli, independent of the sniff frequency used to sample the odorant, and similar for weak and strong odorant-evoked Inputs. Instead, we found that tonic inhibition was a major determinant of receptor Input strength; this tonic inhibition in turn was dependent on glutamatergic transmission from second-order neurons in the glomerular layer. Thus, rather than adaptively shaping odor representations in an activity-dependent manner, a primary role of presynaptic inhibition in vivo may be to modulate the magnitude of Sensory Input to the brain as a function of behavioral state.
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sniffing controls an adaptive filter of Sensory Input to the olfactory bulb
Nature Neuroscience, 2007Co-Authors: Justus V. Verhagen, Daniel W Wesson, Theoden I Netoff, John A White, Matt WachowiakAbstract:Most Sensory stimuli are actively sampled, yet the role of sampling behavior in shaping Sensory codes is poorly understood. Mammals sample odors by sniffing, a complex behavior that controls odorant access to receptor neurons. Whether sniffing shapes the neural code for odors remains unclear. We addressed this question by imaging receptor Input to the olfactory bulb of awake rats performing odor discriminations that elicited different sniffing behaviors. High-frequency sniffing of an odorant attenuated Inputs encoding that odorant, whereas lower sniff frequencies caused little attenuation. Odorants encountered later in a sniff bout were encoded as the combination of that odorant and the background odorant during low-frequency sniffing, but were encoded as the difference between the two odorants during high-frequency sniffing. Thus, sniffing controls an adaptive filter for detecting changes in the odor landscape. These data suggest an unexpected functional role for sniffing and show that Sensory codes can be transformed by sampling behavior alone.
