Dynamic properties of sensory stimulation evoked responses in mouse cerebellar granule cell layer and molecular layer.

Science.gov (United States)

Bing, Yan-Hua; Zhang, Guang-Jian; Sun, Lei; Chu, Chun-Ping; Qiu, De-Lai

2015-01-12

Sensory information coming from climbing fiber and mossy fiber-granule cell pathways, generates motor-related outputs according to internal rules of integration and computation in the cerebellar cortex. However, the dynamic properties of sensory information processing in mouse cerebellar cortex are less understood. Here, we studied the dynamic properties of sensory stimulation-evoked responses in the cerebellar granule cell layer (GCL) and molecular layer (ML) by electrophysiological recordings method. Our data showed that air-puff stimulation (5-10 ms in duration) of the ipsilateral whisker pad evoked single-peak responses in the GCL and ML; whereas a duration of stimulation ≥30 ms in GCL and ≥60 ms in ML, evoked double-peak responses that corresponded with stimulation-on and -off responses via mossy fiber pathway. The highest frequency of stimulation train for evoking GCL responses was 33 Hz. In contrast, the highest frequency of stimulation train for evoking ML responses was 4 Hz. These results indicate that the cerebellar granule cells transfer the high-fidelity sensory information from mossy fibers, which is cut-off by molecular layer interneurons (MLIs). Our results suggest that the MLIs network acts as a low-pass filter during the processing of high-frequency sensory information. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A translational study on looming-evoked defensive response and the underlying subcortical pathway in autism.

Science.gov (United States)

Hu, Yu; Chen, Zhuoming; Huang, Lu; Xi, Yue; Li, Bingxiao; Wang, Hong; Yan, Jiajian; Lee, Tatia M C; Tao, Qian; So, Kwok-Fai; Ren, Chaoran

2017-11-07

Rapidly approaching objects indicating threats can induce defensive response through activating a subcortical pathway comprising superior colliculus (SC), lateral posterior nucleus (LP), and basolateral amygdala (BLA). Abnormal defensive response has been reported in autism, and impaired synaptic connections could be the underlying mechanism. Whether the SC-LP-BLA pathway processes looming stimuli abnormally in autism is not clear. Here, we found that looming-evoked defensive response is impaired in a subgroup of the valproic acid (VPA) mouse model of autism. By combining the conventional neurotracer and transneuronal rabies virus tracing techniques, we demonstrated that synaptic connections in the SC-LP-BLA pathway were abnormal in VPA mice whose looming-evoked defensive responses were absent. Importantly, we further translated the finding to children with autism and observed that they did not present looming-evoked defensive response. Furthermore, the findings of the DTI with the probabilistic tractography showed that the structural connections of SC-pulvinar-amygdala in autism children were weak. The pulvinar is parallel to the LP in a mouse. Because looming-evoked defensive response is innate in humans and emerges much earlier than do social and language functions, the absence of defensive response could be an earlier sign of autism in children.

Is the auditory evoked P2 response a biomarker of learning?

Directory of Open Access Journals (Sweden)

Kelly eTremblay

2014-02-01

Full Text Available Even though auditory training exercises for humans have been shown to improve certain perceptual skills of individuals with and without hearing loss, there is a lack of knowledge pertaining to which aspects of training are responsible for the perceptual gains, and which aspects of perception are changed. To better define how auditory training impacts brain and behavior, electroencephalography and magnetoencephalography have been used to determine the time course and coincidence of cortical modulations associated with different types of training. Here we focus on P1-N1-P2 auditory evoked responses (AEP, as there are consistent reports of gains in P2 amplitude following various types of auditory training experiences; including music and speech-sound training. The purpose of this experiment was to determine if the auditory evoked P2 response is a biomarker of learning. To do this, we taught native English speakers to identify a new pre-voiced temporal cue that is not used phonemically in the English language so that coinciding changes in evoked neural activity could be characterized. To differentiate possible effects of repeated stimulus exposure and a button-pushing task from learning itself, we examined modulations in brain activity in a group of participants who learned to identify the pre-voicing contrast and compared it to participants, matched in time, and stimulus exposure, that did not. The main finding was that the amplitude of the P2 auditory evoked response increased across repeated EEG sessions for all groups, regardless of any change in perceptual performance. What’s more, these effects were retained for months. Changes in P2 amplitude were attributed to changes in neural activity associated with the acquisition process and not the learned outcome itself. A further finding was the expression of a late negativity (LN wave 600-900 ms post-stimulus onset, post-training, exclusively for the group that learned to identify the pre

Brain stem auditory evoked responses in chronic alcoholics.

OpenAIRE

Chan, Y W; McLeod, J G; Tuck, R R; Feary, P A

1985-01-01

Brain stem auditory evoked responses (BAERs) were performed on 25 alcoholic patients with Wernicke-Korsakoff syndrome, 56 alcoholic patients without Wernicke-Korsakoff syndrome, 24 of whom had cerebellar ataxia, and 37 control subjects. Abnormal BAERs were found in 48% of patients with Wernicke-Korsakoff syndrome, in 25% of alcoholic patients without Wernicke-Korsakoff syndrome but with cerebellar ataxia, and in 13% of alcoholic patients without Wernicke-Korsakoff syndrome or ataxia. The mean...

Inhibition of somatosensory-evoked cortical responses by a weak leading stimulus.

Science.gov (United States)

Nakagawa, Kei; Inui, Koji; Yuge, Louis; Kakigi, Ryusuke

2014-11-01

We previously demonstrated that auditory-evoked cortical responses were suppressed by a weak leading stimulus in a manner similar to the prepulse inhibition (PPI) of startle reflexes. The purpose of the present study was to investigate whether a similar phenomenon was present in the somatosensory system, and also whether this suppression reflected an inhibitory process. We recorded somatosensory-evoked magnetic fields following stimulation of the median nerve and evaluated the extent by which they were suppressed by inserting leading stimuli at an intensity of 2.5-, 1.5-, 1.1-, or 0.9-fold the sensory threshold (ST) in healthy participants (Experiment 1). The results obtained demonstrated that activity in the secondary somatosensory cortex in the hemisphere contralateral to the stimulated side (cSII) was significantly suppressed by a weak leading stimulus with the intensity larger than 1.1-fold ST. This result implied that the somatosensory system had an inhibitory process similar to that of PPI. We then presented two successive leading stimuli before the test stimulus, and compared the extent of suppression between the test stimulus-evoked responses and those obtained with the second prepulse alone and with two prepulses (first and second) (Experiment 2). When two prepulses were preceded, cSII responses to the second prepulse were suppressed by the first prepulse, whereas the ability of the second prepulse to suppress the test stimulus remained unchanged. These results suggested the presence of at least two individual pathways; response-generating and inhibitory pathways. Copyright © 2014 Elsevier Inc. All rights reserved.

Visually-evoked pattern and photomyoclonic responses in video game and television epilepsy: case reports.

Science.gov (United States)

Anyanwu, E; Watson, N A

1996-01-01

This research paper reports a case study of two male photosensitive epileptic patients, aged 14 and 16 years old respectively, whose epileptic seizures were often triggered by the flickers from television and video games respectively. The 14-year old patient had no family history of epilepsy, while the 16 year old had a family history of epilepsy. A comprehensive electroencephalogram (EEG), including hyperventilation, intermittent photic stimulation (IPS) and pattern stimulation were carried out on them and EEG abnormalities including photoparoxysmal responses (PPR) and generalized myoclonic responses were evoked. A thorough analysis of the EEG morphology of the myclonic responses and the clinical manifestations showed evidence of two separate entitles of seizures namely: visually evoked pattern-myoclonic responses (PTMR) and visually evoked photomyoclonic responses (PMR). PTMR was independent of flash rate and occurred before a PPR and at the same time as the flash rate, while PMR occurred after the PPR and was dependent on flash rate. These findings suggest that "Video Game" epilepsy is probably a pattern sensitive epilepsy, electronic screen being the source of the triggering patterns; hence, the morphology and the family histories and the myoclonic phenomena differ from those of pure photosensitive epilepsy.

Newborn hearing screening with transient evoked otoacoustic emissions and automatic auditory brainstem response

OpenAIRE

Renata Mota Mamede de Carvallo; Carla Gentile Matas; Isabela de Souza Jardim

2008-01-01

Objective: The aim of the present investigation was to check Transient Evoked Otoacoustic Emissions and Automatic Auditory Brainstem Response tests applied together in regular nurseries and Newborn Intensive Care Units (NICU), as well as to describe and compare the results obtained in both groups. Methods: We tested 150 newborns from regular nurseries and 70 from NICU. Rresults: The newborn hearing screening results using Transient Evoked Otoacoustic Emissions and Automatic Auditory Brainstem...

Peripheral vascular response to mild indirect cooling in patients with homozygous sickle cell (SS) disease and the frequency of painful crisis.

Science.gov (United States)

Mohan, J; Marshall, J M; Reid, H L; Thomas, P W; Hambleton, I; Serjeant, G R

1998-02-01

1. In homozygous sickle cell (SS) disease, skin cooling is a common precipitating factor of the painful crisis which is associated with avascular necrosis of active bone marrow. Since skin cooling does not directly induce sickling, we have investigated the nature of the reflex vascular responses to mild cooling in SS patients in a steady state of the disease and compared them with their history of painful crises. 2. Experiments were performed in Jamaica on 60 male SS patients and 30 matched control subjects with normal haemoglobin (AA) genotype. Forearm blood flow (FBF) was measured by venous occlusion plethysmography and mean arterial pressure (MAP) by a Finapres device: forearm vascular resistance (FVR) was calculated as MAP/FBF. Cutaneous erythrocyte flux in forearm and hand was monitored by a laser Doppler meter. The contralateral hand was immersed in cool water at 16 degrees C for 2 min, 6 times, at random intervals of 0.5-3 min. 3. The first cool immersion evoked an increase in MAP, cutaneous vasoconstriction and a net increase in FVR in both AA and SS subjects. However, the direction of change in FVR varied between individuals such that 18 AA subjects showed an increase in FVR (constrictor group) while 12 showed a decrease in FVR, indicating vasodilatation in forearm muscle (dilator group). In contrast, 50 SS subjects showed an increase in FVR and only 10 showed a decrease in FVR. The proportion of subjects who showed net vasoconstriction was significantly greater in the SS than in the AA group (83% versus 60%, P = 0.03, chi 2 test). 4. By the sixth cool stimulus, the 'dilator' group of AA subjects showed no change in FVR while the 'dilator' group of SS patients showed an increase in FVR. We suggest that forearm muscle vasodilatation was the characteristic component of the alerting/defence response to novel or noxious stimuli which habituates on repetition. 5. In the whole group of SS patients, baseline values of cutaneous vascular resistance and FVR

Vaccine-induced inflammation attenuates the vascular responses to mental stress

NARCIS (Netherlands)

Paine, N.J.; Ring, C.; Bosch, J.A.; Drayson, M.T.; Aldred, S.; Veldhuijzen van Zanten, J.J.C.S.

2014-01-01

Inflammation is associated with poorer vascular function, with evidence to suggest that inflammation can also impair the vascular responses to mental stress. This study examined the effects of vaccine-induced inflammation on vascular responses to mental stress in healthy participants. Eighteen male

Parabrachial complex glutamate receptors modulate the cardiorespiratory response evoked from hypothalamic defense area.

Science.gov (United States)

Díaz-Casares, A; López-González, M V; Peinado-Aragonés, C A; González-Barón, S; Dawid-Milner, M S

2012-08-16

To characterize the possible role of glutamate in the interaction between Hypothalamic Defense Area (HDA) and Parabrachial complex (PBc) nuclei, cardiorespiratory changes were analyzed in response to electrical stimulation of the HDA (1 ms pulses, 30-50 μA given at 100 Hz for 5s) before and after the microinjection of the nonspecific glutamate receptor antagonist kynurenic acid (50 nl, 5 nmol), NMDA receptor antagonist MK-801 (50 nl, 50 nmol), non-NMDA receptor antagonist CNQX (50 nl, 50 nmol) or metabotropic glutamate receptor antagonist MCPG (50 nl, 5 nmol) within the PBc. HDA stimulation evoked an inspiratory facilitatory response, consisting of an increase in respiratory rate (pHDA stimulation. Similarly, the magnitude of the tachycardia and the pressor response was decreased after the microinjection of MK-801 (pHDA stimulation but the respiratory response persisted unchanged after MK-801 or CNQX microinjection into the lPB. Kynurenic acid within the medial parabrachial region (mPB) abolished the tachycardia (pHDA stimulation. MK-801 and CNQX microinjection in this region decreased the magnitude of the tachycardia (pHDA stimulation was not changed after the microinjection of kynurenic acid, MK-801 or CNQX within the mPB. No changes were observed in the cardiorespiratory response evoked to HDA stimulation after MCPG microinjection within lPB and mPB. These results indicate that glutamate PBc receptors are involved in the cardiorespiratory response evoked from the HDA. The possible mechanisms involved in these interactions are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Postural threat differentially affects the feedforward and feedback components of the vestibular-evoked balance response.

Science.gov (United States)

Osler, Callum J; Tersteeg, M C A; Reynolds, Raymond F; Loram, Ian D

2013-10-01

Circumstances may render the consequence of falling quite severe, thus maximising the motivation to control postural sway. This commonly occurs when exposed to height and may result from the interaction of many factors, including fear, arousal, sensory information and perception. Here, we examined human vestibular-evoked balance responses during exposure to a highly threatening postural context. Nine subjects stood with eyes closed on a narrow walkway elevated 3.85 m above ground level. This evoked an altered psycho-physiological state, demonstrated by a twofold increase in skin conductance. Balance responses were then evoked by galvanic vestibular stimulation. The sway response, which comprised a whole-body lean in the direction of the edge of the walkway, was significantly and substantially attenuated after ~800 ms. This demonstrates that a strong reason to modify the balance control strategy was created and subjects were highly motivated to minimise sway. Despite this, the initial response remained unchanged. This suggests little effect on the feedforward settings of the nervous system responsible for coupling pure vestibular input to functional motor output. The much stronger, later effect can be attributed to an integration of balance-relevant sensory feedback once the body was in motion. These results demonstrate that the feedforward and feedback components of a vestibular-evoked balance response are differently affected by postural threat. Although a fear of falling has previously been linked with instability and even falling itself, our findings suggest that this relationship is not attributable to changes in the feedforward vestibular control of balance. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Roux-en-Y gastric bypass augments the feeding responses evoked by gastrin releasing peptides

Science.gov (United States)

Washington, Martha C.; Mhalhal, Thaer R.; Berger, Tanisha Johnson-Rouse Jose; Heath, John; Seeley, Randy; Sayegh, Ayman I.

2016-01-01

Background Roux-en-Y gastric bypass (RYGB) is the most effective method for the treatment of obesity and metabolic disease Roux-en-Y gastric bypass (RYGB) may reduce body weight by altering the feeding responses evoked by the short term satiety peptides. Materials and Methods Here, we measured meal size (MS, chow), intermeal interval (IMI) length and satiety ratio (SR, IMI/MS; food consumed per a unit of time) by the small and the large forms of gastrin releasing peptide (GRP) in rats, GRP-10 and GRP-29 (0, 0.1, 0.5 nmol/kg) infused in the celiac artery (CA, supplies stomach and upper duodenum) and the cranial mesenteric artery (CMA, supplies small and large intestine) in a RYGB rat model. Results GRP-10 reduced MS, prolonged the IMI and increased the SR only in the RYGB group, whereas GRP-29 evoked these responses by both routes and in both groups. Conclusion The RYGB procedure augments the feeding responses evoked by exogenous GRP, possibly by decreasing total food intake, increasing latency to the first meal, decreasing number of meals or altering the sites of action regulating MS and IMI length by the two peptides. PMID:27884350

Altered Evoked Gamma-Band Responses Reveal Impaired Early Visual Processing in ADHD Children

Science.gov (United States)

Lenz, Daniel; Krauel, Kerstin; Flechtner, Hans-Henning; Schadow, Jeanette; Hinrichs, Hermann; Herrmann, Christoph S.

2010-01-01

Neurophysiological studies yield contrary results whether attentional problems of patients with attention-deficit/hyperactivity disorder (ADHD) are related to early visual processing deficits or not. Evoked gamma-band responses (GBRs), being among the first cortical responses occurring as early as 90 ms after visual stimulation in human EEG, have…

Modulation of visually evoked postural responses by contextual visual, haptic and auditory information: a 'virtual reality check'.

Science.gov (United States)

Meyer, Georg F; Shao, Fei; White, Mark D; Hopkins, Carl; Robotham, Antony J

2013-01-01

Externally generated visual motion signals can cause the illusion of self-motion in space (vection) and corresponding visually evoked postural responses (VEPR). These VEPRs are not simple responses to optokinetic stimulation, but are modulated by the configuration of the environment. The aim of this paper is to explore what factors modulate VEPRs in a high quality virtual reality (VR) environment where real and virtual foreground objects served as static visual, auditory and haptic reference points. Data from four experiments on visually evoked postural responses show that: 1) visually evoked postural sway in the lateral direction is modulated by the presence of static anchor points that can be haptic, visual and auditory reference signals; 2) real objects and their matching virtual reality representations as visual anchors have different effects on postural sway; 3) visual motion in the anterior-posterior plane induces robust postural responses that are not modulated by the presence of reference signals or the reality of objects that can serve as visual anchors in the scene. We conclude that automatic postural responses for laterally moving visual stimuli are strongly influenced by the configuration and interpretation of the environment and draw on multisensory representations. Different postural responses were observed for real and virtual visual reference objects. On the basis that automatic visually evoked postural responses in high fidelity virtual environments should mimic those seen in real situations we propose to use the observed effect as a robust objective test for presence and fidelity in VR.

Noise-evoked otoacoustic emissions in humans

NARCIS (Netherlands)

Maat, B; Wit, HP; van Dijk, P

2000-01-01

Click-evoked otoacoustic emissions (CEOAEs) and acoustical responses evoked by bandlimited Gaussian noise (noise-evoked otoacoustic emissions; NEOAEs) were measured in three normal-hearing subjects. For the NEOAEs the first- and second-order Wiener kernel and polynomial correlation functions up to

Vascular Response of the Segments Adjacent to the Proximal and Distal Edges of the ABSORB Everolimus-Eluting Bioresorbable Vascular Scaffold

DEFF Research Database (Denmark)

Gogas, Bill D; Serruys, Patrick W; Diletti, Roberto

2012-01-01

This study sought to investigate in vivo the vascular response at the proximal and distal edges of the second-generation ABSORB everolimus-eluting bioresorbable vascular scaffold (BVS).......This study sought to investigate in vivo the vascular response at the proximal and distal edges of the second-generation ABSORB everolimus-eluting bioresorbable vascular scaffold (BVS)....

Synaptic responses evoked by tactile stimuli in Purkinje cells in mouse cerebellar cortex Crus II in vivo.

Directory of Open Access Journals (Sweden)

Chun-Ping Chu

Full Text Available Sensory stimuli evoke responses in cerebellar Purkinje cells (PCs via the mossy fiber-granule cell pathway. However, the properties of synaptic responses evoked by tactile stimulation in cerebellar PCs are unknown. The present study investigated the synaptic responses of PCs in response to an air-puff stimulation on the ipsilateral whisker pad in urethane-anesthetized mice.Thirty-three PCs were recorded from 48 urethane-anesthetized adult (6-8-week-old HA/ICR mice by somatic or dendritic patch-clamp recording and pharmacological methods. Tactile stimulation to the ipsilateral whisker pad was delivered by an air-puff through a 12-gauge stainless steel tube connected with a pressurized injection system. Under current-clamp conditions (I = 0, the air-puff stimulation evoked strong inhibitory postsynaptic potentials (IPSPs in the somata of PCs. Application of SR95531, a specific GABA(A receptor antagonist, blocked IPSPs and revealed stimulation-evoked simple spike firing. Under voltage-clamp conditions, tactile stimulation evoked a sequence of transient inward currents followed by strong outward currents in the somata and dendrites in PCs. Application of SR95531 blocked outward currents and revealed excitatory postsynaptic currents (EPSCs in somata and a temporal summation of parallel fiber EPSCs in PC dendrites. We also demonstrated that PCs respond to both the onset and offset of the air-puff stimulation.These findings indicated that tactile stimulation induced asynchronous parallel fiber excitatory inputs onto the dendrites of PCs, and failed to evoke strong EPSCs and spike firing in PCs, but induced the rapid activation of strong GABA(A receptor-mediated inhibitory postsynaptic currents in the somata and dendrites of PCs in the cerebellar cortex Crus II in urethane-anesthetized mice.

EEG and EMG responses to emotion-evoking stimuli processed without conscious awareness.

Science.gov (United States)

Wexler, B E; Warrenburg, S; Schwartz, G E; Janer, L D

1992-12-01

Dichotic stimulus pairs were constructed with one word that was emotionally neutral and another that evoked either negative or positive feelings. Temporal and spectral overlap between the members of each pair was so great that the two words fused into a single auditory percept. Subjects were consciously aware of hearing only one word from most pairs; sometimes the emotion-evoking word was heard consciously, other times the neutral word was heard consciously. Subjects were instructed to let their thoughts wander in response to the word they heard, during which time EEG alpha activity over left and right frontal regions, and muscle activity (EMG) in the corrugator ("frowning") and zygomatic ("smiling") regions were recorded. Both EEG and EMG provided evidence of emotion-specific responses to stimuli that were processed without conscious awareness. Moreover both suggested relatively greater right hemisphere activity with unconscious rather than conscious processing.

Effect of peripherally and cortically evoked swallows on jaw reflex responses in anesthetized rabbits.

Science.gov (United States)

Suzuki, Taku; Yoshihara, Midori; Sakai, Shogo; Tsuji, Kojun; Nagoya, Kouta; Magara, Jin; Tsujimura, Takanori; Inoue, Makoto

2018-05-03

This study aimed to investigate whether the jaw-opening (JOR) and jaw-closing reflexes (JCR) are modulated during not only peripherally, but also centrally, evoked swallowing. Experiments were carried out on 24 adult male Japanese white rabbits. JORs were evoked by trigeminal stimulation at 1 Hz for 30 sec. In the middle 10 sec, either the superior laryngeal nerve (SLN) or cortical swallowing area (Cx) was simultaneously stimulated to evoke swallowing. The peak-to-peak JOR amplitude was reduced during the middle and late 10-sec periods (i.e., during and after SLN or Cx stimulation), and the reduction was dependent on the current intensity of SLN/Cx stimulation: greater SLN/Cx stimulus current resulted in greater JOR inhibition. The reduction rate was significantly greater during Cx stimulation than during SLN stimulation. The amplitude returned to baseline 2 min after 10-sec SLN/Cx stimulation. The effect of co-stimulation of SLN and Cx was significantly greater than that of SLN stimulation alone. There were no significant differences in any parameters of the JCR between conditions. These results clearly showed that JOR responses were significantly suppressed, not only during peripherally evoked swallowing but also during centrally evoked swallowing, and that the inhibitory effect is likely to be larger during centrally compared with peripherally evoked swallowing. The functional implications of these results are discussed. Copyright © 2018. Published by Elsevier B.V.

Modulation of visually evoked postural responses by contextual visual, haptic and auditory information: a 'virtual reality check'.

Directory of Open Access Journals (Sweden)

Georg F Meyer

Full Text Available Externally generated visual motion signals can cause the illusion of self-motion in space (vection and corresponding visually evoked postural responses (VEPR. These VEPRs are not simple responses to optokinetic stimulation, but are modulated by the configuration of the environment. The aim of this paper is to explore what factors modulate VEPRs in a high quality virtual reality (VR environment where real and virtual foreground objects served as static visual, auditory and haptic reference points. Data from four experiments on visually evoked postural responses show that: 1 visually evoked postural sway in the lateral direction is modulated by the presence of static anchor points that can be haptic, visual and auditory reference signals; 2 real objects and their matching virtual reality representations as visual anchors have different effects on postural sway; 3 visual motion in the anterior-posterior plane induces robust postural responses that are not modulated by the presence of reference signals or the reality of objects that can serve as visual anchors in the scene. We conclude that automatic postural responses for laterally moving visual stimuli are strongly influenced by the configuration and interpretation of the environment and draw on multisensory representations. Different postural responses were observed for real and virtual visual reference objects. On the basis that automatic visually evoked postural responses in high fidelity virtual environments should mimic those seen in real situations we propose to use the observed effect as a robust objective test for presence and fidelity in VR.

A comparison of myogenic motor evoked responses to electrical and magnetic transcranial stimulation during nitrous oxide/opioid anesthesia

NARCIS (Netherlands)

Ubags, L. H.; Kalkman, C. J.; Been, H. D.; Koelman, J. H.; Ongerboer de Visser, B. W.

1999-01-01

Transcranial motor evoked potentials (tc-MEPs) are used to monitor spinal cord integrity intraoperatively. We compared myogenic motor evoked responses with electrical and magnetic transcranial stimuli during nitrous oxide/opioid anesthesia. In 11 patients undergoing spinal surgery, anesthesia was

Modulation of Visually Evoked Postural Responses by Contextual Visual, Haptic and Auditory Information: A ‘Virtual Reality Check’

Science.gov (United States)

Meyer, Georg F.; Shao, Fei; White, Mark D.; Hopkins, Carl; Robotham, Antony J.

2013-01-01

Externally generated visual motion signals can cause the illusion of self-motion in space (vection) and corresponding visually evoked postural responses (VEPR). These VEPRs are not simple responses to optokinetic stimulation, but are modulated by the configuration of the environment. The aim of this paper is to explore what factors modulate VEPRs in a high quality virtual reality (VR) environment where real and virtual foreground objects served as static visual, auditory and haptic reference points. Data from four experiments on visually evoked postural responses show that: 1) visually evoked postural sway in the lateral direction is modulated by the presence of static anchor points that can be haptic, visual and auditory reference signals; 2) real objects and their matching virtual reality representations as visual anchors have different effects on postural sway; 3) visual motion in the anterior-posterior plane induces robust postural responses that are not modulated by the presence of reference signals or the reality of objects that can serve as visual anchors in the scene. We conclude that automatic postural responses for laterally moving visual stimuli are strongly influenced by the configuration and interpretation of the environment and draw on multisensory representations. Different postural responses were observed for real and virtual visual reference objects. On the basis that automatic visually evoked postural responses in high fidelity virtual environments should mimic those seen in real situations we propose to use the observed effect as a robust objective test for presence and fidelity in VR. PMID:23840760

Vasculo-Neuronal Coupling: Retrograde Vascular Communication to Brain Neurons.

Science.gov (United States)

Kim, Ki Jung; Ramiro Diaz, Juan; Iddings, Jennifer A; Filosa, Jessica A

2016-12-14

Continuous cerebral blood flow is essential for neuronal survival, but whether vascular tone influences resting neuronal function is not known. Using a multidisciplinary approach in both rat and mice brain slices, we determined whether flow/pressure-evoked increases or decreases in parenchymal arteriole vascular tone, which result in arteriole constriction and dilation, respectively, altered resting cortical pyramidal neuron activity. We present evidence for intercellular communication in the brain involving a flow of information from vessel to astrocyte to neuron, a direction opposite to that of classic neurovascular coupling and referred to here as vasculo-neuronal coupling (VNC). Flow/pressure increases within parenchymal arterioles increased vascular tone and simultaneously decreased resting pyramidal neuron firing activity. On the other hand, flow/pressure decreases evoke parenchymal arteriole dilation and increased resting pyramidal neuron firing activity. In GLAST-CreERT2; R26-lsl-GCaMP3 mice, we demonstrate that increased parenchymal arteriole tone significantly increased intracellular calcium in perivascular astrocyte processes, the onset of astrocyte calcium changes preceded the inhibition of cortical pyramidal neuronal firing activity. During increases in parenchymal arteriole tone, the pyramidal neuron response was unaffected by blockers of nitric oxide, GABA A , glutamate, or ecto-ATPase. However, VNC was abrogated by TRPV4 channel, GABA B , as well as an adenosine A 1 receptor blocker. Differently to pyramidal neuron responses, increases in flow/pressure within parenchymal arterioles increased the firing activity of a subtype of interneuron. Together, these data suggest that VNC is a complex constitutive active process that enables neurons to efficiently adjust their resting activity according to brain perfusion levels, thus safeguarding cellular homeostasis by preventing mismatches between energy supply and demand. We present evidence for vessel

Auditory evoked responses to binaural beat illusion: stimulus generation and the derivation of the Binaural Interaction Component (BIC).

Science.gov (United States)

Ozdamar, Ozcan; Bohorquez, Jorge; Mihajloski, Todor; Yavuz, Erdem; Lachowska, Magdalena

2011-01-01

Electrophysiological indices of auditory binaural beats illusions are studied using late latency evoked responses. Binaural beats are generated by continuous monaural FM tones with slightly different ascending and descending frequencies lasting about 25 ms presented at 1 sec intervals. Frequency changes are carefully adjusted to avoid any creation of abrupt waveform changes. Binaural Interaction Component (BIC) analysis is used to separate the neural responses due to binaural involvement. The results show that the transient auditory evoked responses can be obtained from the auditory illusion of binaural beats.

A5 region modulation of the cardiorespiratory responses evoked from parabrachial cell bodies in the anaesthetised rat.

Science.gov (United States)

Dawid Milner, M S; Lara, J P; López de Miguel, M P; López-González, M V; Spyer, K M; González-Barón, S

2003-08-22

We have examined the importance of the A5 region modulating cardiorespiratory responses evoked from the parabrachial complex (PB) in spontaneously breathing rats. Cardiorespiratory changes were analyzed in response to electrical stimulation and glutamate microinjections into the PB (10-20 nl, 1-2 nmol) before and after ipsilateral microinjection of muscimol (50 nl, 0.25 nmol) or lidocaine (50 nl, 0.5 nmol) within the A5 region. Stimulation of medial parabrachial and Kölliker-Fuse nuclei (mPB-KF) evoked a decrease in respiratory rate (Pinteractions between A5 and PB, extracellular recordings of putative A5 neurones were obtained during PB stimulation. Eighty-three A5 cells were recorded, 35 were activated from the mPB-KF (42%). The results indicate that neurones of the A5 region participate in the cardiorespiratory response evoked from the different regions of the PB complex. The possible mechanisms involved in these interactions are discussed.

The Duration of Motor Responses Evoked with Intracortical Microstimulation in Rats Is Primarily Modulated by Stimulus Amplitude and Train Duration.

Directory of Open Access Journals (Sweden)

Meghan Watson

Full Text Available Microstimulation of brain tissue plays a key role in a variety of sensory prosthetics, clinical therapies and research applications, however the effects of stimulation parameters on the responses they evoke remain widely unknown. In particular, the effects of parameters when delivered in the form of a stimulus train as opposed to a single pulse are not well understood despite the prevalence of stimulus train use. We aimed to investigate the contribution of each parameter of a stimulus train to the duration of the motor responses they evoke in forelimb muscles. We used constant-current, biphasic, square wave pulse trains in acute terminal experiments under ketamine anaesthesia. Stimulation parameters were systematically tested in a pair-wise fashion in the caudal forelimb region of the motor cortex in 7 Sprague-Dawley rats while motor evoked potential (MEP recordings from the forelimb were used to quantify the influence of each parameter in the train. Stimulus amplitude and train duration were shown to be the dominant parameters responsible for increasing the total duration of the MEP, while interphase interval had no effect. Increasing stimulus frequency from 100-200 Hz or pulse duration from 0.18-0.34 ms were also effective methods of extending response durations. Response duration was strongly correlated with peak time and amplitude. Our findings suggest that motor cortex intracortical microstimulations are often conducted at a higher frequency rate and longer train duration than necessary to evoke maximal response duration. We demonstrated that the temporal properties of the evoked response can be both predicted by certain response metrics and modulated via alterations to the stimulation signal parameters.

Eccentric-exercise induced inflammation attenuates the vascular responses to mental stress

NARCIS (Netherlands)

Paine, N.J.; Ring, C.; Aldred, S.; Bosch, J.A.; Wadley, A.J.; Veldhuijzen van Zanten, J.J.C.S.

2013-01-01

Mental stress has been identified as a trigger of myocardial infarction (MI), with inflammation and vascular responses to mental stress independently implicated as contributing factors. This study examined whether inflammation moderates the vascular responses to mental stress. Eighteen healthy male

Event-related fields evoked by vocal response inhibition: a comparison of younger and older adults.

Science.gov (United States)

Castro-Meneses, Leidy J; Johnson, Blake W; Sowman, Paul F

2016-06-01

The current study examined event-related fields (ERFs) evoked by vocal response inhibition in a stimulus-selective stop-signal task. We compared inhibition-related ERFs across a younger and an older group of adults. Behavioural results revealed that stop-signal reaction times (RTs), go-RTs, ignore-stop RTs and failed stop RTs were longer in the older, relative to the younger group by 38, 123, 149 and 116 ms, respectively. The amplitude of the ERF M2 peak (approximately 200 ms after the stop signal) evoked on successful stop trials was larger compared to that evoked on both failed stop and ignore-stop trials. The M4 peak (approximately 450 ms after stop signal) was of larger amplitude in both successful and failed stops compared to ignore-stop trials. In the older group, the M2, M3 and M4 peaks were smaller in amplitude and peaked later in time (by 24, 50 and 76 ms, respectively). We demonstrate that vocal response inhibition-related ERFs exhibit a similar temporal evolution to those previously described for manual response inhibition: an early peak at 200 ms (i.e. M2) that differentiates successful from failed stopping, and a later peak (i.e. M4) that is consistent with a neural marker of response checking and error processing. Across groups, our data support a more general decline of stimulus processing speed with age.

Whiplash evokes descending muscle recruitment and sympathetic responses characteristic of startle

Science.gov (United States)

Mang, Daniel WH; Siegmund, Gunter P; Blouin, Jean-Sébastien

2014-01-01

Whiplash injuries are the most common injuries following rear-end collisions. During a rear-end collision, the human muscle response consists of both a postural and a startle response that may exacerbate injury. However, most previous studies only assessed the presence of startle using data collected from the neck muscles and head/neck kinematics. The startle response also evokes a descending pattern of muscle recruitment and changes in autonomic activity. Here we examined the recruitment of axial and appendicular muscles along with autonomic responses to confirm whether these other features of a startle response were present during the first exposure to a whiplash perturbation. Ten subjects experienced a single whiplash perturbation while recording electromyography, electrocardiogram, and electrodermal responses. All subjects exhibited a descending pattern of muscle recruitment, and increasing heart rate and electrodermal responses following the collision. Our results provide further support that the startle response is a component of the response to whiplash collisions. PMID:24932015

Roles of N-methyl-d-aspartate receptors during the sensory stimulation-evoked field potential responses in mouse cerebellar cortical molecular layer.

Science.gov (United States)

Xu, Yin-Hua; Zhang, Guang-Jian; Zhao, Jing-Tong; Chu, Chun-Ping; Li, Yu-Zi; Qiu, De-Lai

2017-11-01

The functions of N-methyl-d-aspartate receptors (NMDARs) in cerebellar cortex have been widely studied under in vitro condition, but their roles during the sensory stimulation-evoked responses in the cerebellar cortical molecular layer in living animals are currently unclear. We here investigated the roles of NMDARs during the air-puff stimulation on ipsilateral whisker pad-evoked field potential responses in cerebellar cortical molecular layer in urethane-anesthetized mice by electrophysiological recording and pharmacological methods. Our results showed that cerebellar surface administration of NMDA induced a dose-dependent decrease in amplitude of the facial stimulation-evoked inhibitory responses (P1) in the molecular layer, accompanied with decreases in decay time, half-width and area under curve (AUC) of P1. The IC 50 of NMDA induced inhibition in amplitude of P1 was 46.5μM. In addition, application of NMDA induced significant increases in the decay time, half-width and AUC values of the facial stimulation-evoked excitatory responses (N1) in the molecular layer. Application of an NMDAR blocker, D-APV (250μM) abolished the facial stimulation-evoked P1 in the molecular layer. These results suggested that NMDARs play a critical role during the sensory information processing in cerebellar cortical molecular layer in vivo in mice. Copyright © 2017 Elsevier B.V. All rights reserved.

Inattentional Deafness: Visual Load Leads to Time-Specific Suppression of Auditory Evoked Responses.

Science.gov (United States)

Molloy, Katharine; Griffiths, Timothy D; Chait, Maria; Lavie, Nilli

2015-12-09

Due to capacity limits on perception, conditions of high perceptual load lead to reduced processing of unattended stimuli (Lavie et al., 2014). Accumulating work demonstrates the effects of visual perceptual load on visual cortex responses, but the effects on auditory processing remain poorly understood. Here we establish the neural mechanisms underlying "inattentional deafness"--the failure to perceive auditory stimuli under high visual perceptual load. Participants performed a visual search task of low (target dissimilar to nontarget items) or high (target similar to nontarget items) load. On a random subset (50%) of trials, irrelevant tones were presented concurrently with the visual stimuli. Brain activity was recorded with magnetoencephalography, and time-locked responses to the visual search array and to the incidental presence of unattended tones were assessed. High, compared to low, perceptual load led to increased early visual evoked responses (within 100 ms from onset). This was accompanied by reduced early (∼ 100 ms from tone onset) auditory evoked activity in superior temporal sulcus and posterior middle temporal gyrus. A later suppression of the P3 "awareness" response to the tones was also observed under high load. A behavioral experiment revealed reduced tone detection sensitivity under high visual load, indicating that the reduction in neural responses was indeed associated with reduced awareness of the sounds. These findings support a neural account of shared audiovisual resources, which, when depleted under load, leads to failures of sensory perception and awareness. The present work clarifies the neural underpinning of inattentional deafness under high visual load. The findings of near-simultaneous load effects on both visual and auditory evoked responses suggest shared audiovisual processing capacity. Temporary depletion of shared capacity in perceptually demanding visual tasks leads to a momentary reduction in sensory processing of auditory

Role of the parabrachial complex in the cardiorespiratory response evoked from hypothalamic defense area stimulation in the anesthetized rat.

Science.gov (United States)

Díaz-Casares, Amelia; López-González, Manuel Víctor; Peinado-Aragonés, Carlos Antonio; Lara, José Pablo; González-Barón, Salvador; Dawid-Milner, Marc Stefan

2009-07-07

To analyze the role of parabrachial complex (PBc) in the modulation of cardiorespiratory response evoked from the hypothalamic defense area (HDA), cardiorespiratory changes were analyzed in spontaneously breathing anesthetised rats in response to electrical stimulation of the HDA (1 ms pulses, 30-50 microA, 100 Hz for 5 s) before and after the microinjection of muscimol (50 nl, 0.25 nmol, 5 s) within the PBc. HDA stimulation evoked an inspiratory facilitatory response, consisting of an increase in respiratory rate (pHDA stimulation (pHDA stimulation. The respiratory response persisted unchanged. Finally, extracellular recording of putative neurons from these regions were obtained during HDA stimulation to confirm functional interaction between HDA and parabrachial regions. 105 pontine cells were recorded during HDA stimulation, 57 from the lPB and 48 from the mPB-KF. In mPB-KF 34/48 (71%) and in lPB 38/57 (67%) cells were influenced from HDA. The results indicate that neurons from different regions of the PBc have an important function in mediating the cardiorespiratory response evoked from the HDA. The possible mechanisms involved in these interactions are discussed.

Analog and digital filtering of the brain stem auditory evoked response.

Science.gov (United States)

Kavanagh, K T; Franks, R

1989-07-01

This study compared the filtering effects on the auditory evoked potential of zero and standard phase shift digital filters (the former was a mathematical approximation of a standard Butterworth filter). Conventional filters were found to decrease the height of the evoked response in the majority of waveforms compared to zero phase shift filters. A 36-dB/octave zero phase shift high pass filter with a cutoff frequency of 100 Hz produced a 16% reduction in wave amplitude compared to the unfiltered control. A 36-dB/octave, 100-Hz standard phase shift high pass filter produced a 41% reduction, and a 12-dB/octave, 150-Hz standard phase shift high pass filter produced a 38% reduction in wave amplitude compared to the unfiltered control. A decrease in the mean along with an increase in the variability of wave IV/V latency was also noted with conventional compared to zero phase shift filters. The increase in the variability of the latency measurement was due to the difficulty in waveform identification caused by the phase shift distortion of the conventional filter along with the variable decrease in wave latency caused by phase shifting responses with different spectral content. Our results indicated that a zero phase shift high pass filter of 100 Hz was the most desirable filter studied for the mitigation of spontaneous brain activity and random muscle artifact.

Development of the acoustically evoked behavioral response in larval plainfin midshipman fish, Porichthys notatus.

Directory of Open Access Journals (Sweden)

Peter W Alderks

Full Text Available The ontogeny of hearing in fishes has become a major interest among bioacoustics researchers studying fish behavior and sensory ecology. Most fish begin to detect acoustic stimuli during the larval stage which can be important for navigation, predator avoidance and settlement, however relatively little is known about the hearing capabilities of larval fishes. We characterized the acoustically evoked behavioral response (AEBR in the plainfin midshipman fish, Porichthys notatus, and used this innate startle-like response to characterize this species' auditory capability during larval development. Age and size of larval midshipman were highly correlated (r(2 = 0.92. The AEBR was first observed in larvae at 1.4 cm TL. At a size ≥ 1.8 cm TL, all larvae responded to a broadband stimulus of 154 dB re1 µPa or -15.2 dB re 1 g (z-axis. Lowest AEBR thresholds were 140-150 dB re 1 µPa or -33 to -23 dB re 1 g for frequencies below 225 Hz. Larval fish with size ranges of 1.9-2.4 cm TL had significantly lower best evoked frequencies than the other tested size groups. We also investigated the development of the lateral line organ and its function in mediating the AEBR. The lateral line organ is likely involved in mediating the AEBR but not necessary to evoke the startle-like response. The midshipman auditory and lateral line systems are functional during early development when the larvae are in the nest and the auditory system appears to have similar tuning characteristics throughout all life history stages.

Development of the acoustically evoked behavioral response in larval plainfin midshipman fish, Porichthys notatus.

Science.gov (United States)

Alderks, Peter W; Sisneros, Joseph A

2013-01-01

The ontogeny of hearing in fishes has become a major interest among bioacoustics researchers studying fish behavior and sensory ecology. Most fish begin to detect acoustic stimuli during the larval stage which can be important for navigation, predator avoidance and settlement, however relatively little is known about the hearing capabilities of larval fishes. We characterized the acoustically evoked behavioral response (AEBR) in the plainfin midshipman fish, Porichthys notatus, and used this innate startle-like response to characterize this species' auditory capability during larval development. Age and size of larval midshipman were highly correlated (r(2) = 0.92). The AEBR was first observed in larvae at 1.4 cm TL. At a size ≥ 1.8 cm TL, all larvae responded to a broadband stimulus of 154 dB re1 µPa or -15.2 dB re 1 g (z-axis). Lowest AEBR thresholds were 140-150 dB re 1 µPa or -33 to -23 dB re 1 g for frequencies below 225 Hz. Larval fish with size ranges of 1.9-2.4 cm TL had significantly lower best evoked frequencies than the other tested size groups. We also investigated the development of the lateral line organ and its function in mediating the AEBR. The lateral line organ is likely involved in mediating the AEBR but not necessary to evoke the startle-like response. The midshipman auditory and lateral line systems are functional during early development when the larvae are in the nest and the auditory system appears to have similar tuning characteristics throughout all life history stages.

The effect of ACTH analogues on motor behavior and visual evoked responses in rats

NARCIS (Netherlands)

Wolthuis, O.L.; Wied, D. de

1976-01-01

Averaged visual evoked responses (VER) in cortical area 17 were recorded one hour after the administration of 7-l-phe ACTH(4-10) or 7-d-phe ACTH(4-10) to artificially ventilated rats, paralysed with gallamine. In addition, the effects of these peptides on spontaneous motor behavior were analyzed.

DESCRIPTION OF BRAINSTEM AUDITORY EVOKED RESPONSES (AIR AND BONE CONDUCTION IN CHILDREN WITH NORMAL HEARING

Directory of Open Access Journals (Sweden)

A. V. Pashkov

2014-01-01

Full Text Available Diagnosis of hearing level in small children with conductive hearing loss associated with congenital craniofacial abnormalities, particularly with agenesis of external ear and external auditory meatus is a pressing issue. Conventional methods of assessing hearing in the first years of life, i. e. registration of brainstem auditory evoked responses to acoustic stimuli in the event of air conduction, does not give an indication of the auditory analyzer’s condition due to potential conductive hearing loss in these patients. This study was aimed at assessing potential of diagnosing the auditory analyzer’s function with registering brainstem auditory evoked responses (BAERs to acoustic stimuli transmitted by means of a bone vibrator. The study involved 17 children aged 3–10 years with normal hearing. We compared parameters of registering brainstem auditory evoked responses (peak V depending on the type of stimulus transmission (air/bone in children with normal hearing. The data on thresholds of the BAERs registered to acoustic stimuli in the event of air and bone conduction obtained in this study are comparable; hearing thresholds in the event of acoustic stimulation by means of a bone vibrator correlates with the results of the BAERs registered to the stimuli transmitted by means of air conduction earphones (r = 0.9. High correlation of thresholds of BAERs to the stimuli transmitted by means of a bone vibrator with thresholds of BAERs registered when air conduction earphones were used helps to assess auditory analyzer’s condition in patients with any form of conductive hearing loss.  

Development of Brainstem-Evoked Responses in Congenital Auditory Deprivation

Directory of Open Access Journals (Sweden)

J. Tillein

2012-01-01

Full Text Available To compare the development of the auditory system in hearing and completely acoustically deprived animals, naive congenitally deaf white cats (CDCs and hearing controls (HCs were investigated at different developmental stages from birth till adulthood. The CDCs had no hearing experience before the acute experiment. In both groups of animals, responses to cochlear implant stimulation were acutely assessed. Electrically evoked auditory brainstem responses (E-ABRs were recorded with monopolar stimulation at different current levels. CDCs demonstrated extensive development of E-ABRs, from first signs of responses at postnatal (p.n. day 3 through appearance of all waves of brainstem response at day 8 p.n. to mature responses around day 90 p.n.. Wave I of E-ABRs could not be distinguished from the artifact in majority of CDCs, whereas in HCs, it was clearly separated from the stimulus artifact. Waves II, III, and IV demonstrated higher thresholds in CDCs, whereas this difference was not found for wave V. Amplitudes of wave III were significantly higher in HCs, whereas wave V amplitudes were significantly higher in CDCs. No differences in latencies were observed between the animal groups. These data demonstrate significant postnatal subcortical development in absence of hearing, and also divergent effects of deafness on early waves II–IV and wave V of the E-ABR.

Vascular responses to radiotherapy and androgendeprivation therapy in experimental prostate cancer

LENUS (Irish Health Repository)

2012-05-23

AbstractBackgroundRadiotherapy (RT) and androgen-deprivation therapy (ADT) are standard treatments for advanced prostate cancer (PC). Tumor vascularization is recognized as an important physiological feature likely to impact on both RT and ADT response, and this study therefore aimed to characterize the vascular responses to RT and ADT in experimental PC.MethodsUsing mice implanted with CWR22 PC xenografts, vascular responses to RT and ADT by castration were visualized in vivo by DCE MRI, before contrast-enhancement curves were analyzed both semi-quantitatively and by pharmacokinetic modeling. Extracted image parameters were correlated to the results from ex vivo quantitative fluorescent immunohistochemical analysis (qIHC) of tumor vascularization (9 F1), perfusion (Hoechst 33342), and hypoxia (pimonidazole), performed on tissue sections made from tumors excised directly after DCE MRI.ResultsCompared to untreated (Ctrl) tumors, an improved and highly functional vascularization was detected in androgen-deprived (AD) tumors, reflected by increases in DCE MRI parameters and by increased number of vessels (VN), vessel density ( VD), and vessel area fraction ( VF) from qIHC. Although total hypoxic fractions ( HF) did not change, estimated acute hypoxia scores ( AHS) – the proportion of hypoxia staining within 50 μm from perfusion staining – were increased in AD tumors compared to in Ctrl tumors. Five to six months after ADT renewed castration-resistant (CR) tumor growth appeared with an even further enhanced tumor vascularization. Compared to the large vascular changes induced by ADT, RT induced minor vascular changes. Correlating DCE MRI and qIHC parameters unveiled the semi-quantitative parameters area under curve ( AUC) from initial time-points to strongly correlate with VD and VF, whereas estimation of vessel size ( VS) by DCE MRI required pharmacokinetic modeling. HF was not correlated to any DCE MRI parameter, however, AHS may be estimated after

The vascular and neurogenic factors associated with erectile dysfunction in patients after pelvic fractures

Directory of Open Access Journals (Sweden)

Yong Guan

2015-10-01

Full Text Available ABSTRACT Erectile dysfunction (ED is a common complication of pelvic fractures. To identify the vascular and neurogenic factors associated with ED, 120 patients admitted with ED after traumatic pelvic fracture between January 2009 and June 2013 were enrolled in this study. All patients answered the International Index of Erectile Function (IIEF-5 questionnaire. Nocturnal penile tumescence (NPT testing confirmed the occurrence of ED in 96 (80% patients on whom penile duplex ultrasound and neurophysiological testing were further performed. Of these ED patients 29 (30% were demonstrated only with vascular abnormality, 41 (42.7% were detected only with neural abnormality, 26 (27.1% revealed mixed abnormalities. Of the 55 patients (29+26 with vascular problems, 7 patients (12.7% with abnormal arterial response to intracavernous injection of Bimix (15mg papaverine and 1mg phentolamine, 31 (56.4% with corporal veno-occlusive dysfunction and 17 (30.9% had both problems. Of the 67 (41+26 patients with abnormal neurophysiological outcomes, 51 (76.1% with abnormal bulbocavernosus reflex (BCR, 20 (29.9% with pathological pudendal nerve evoked potentials (PDEPs and 25 (37.3% with abnormal posterior tibial somatosensory nerve evoked potentials (PTSSEPs. Our observation indicated that neurogenic factors are important for the generation of ED in patients with pelvic fracture; venous impotence is more common than arteriogenic ED.

Cortical stimulation evokes abnormal responses in the dopamine-depleted rat basal ganglia.

Science.gov (United States)

Kita, Hitoshi; Kita, Takako

2011-07-13

The motor cortex (MC) sends massive projections to the basal ganglia. Motor disabilities in patients and animal models of Parkinson's disease (PD) may be caused by dopamine (DA)-depleted basal ganglia that abnormally process the information originating from MC. To study how DA depletion alters signal transfer in the basal ganglia, MC stimulation-induced (MC-induced) unitary responses were recorded from the basal ganglia of control and 6-hydroxydopamine-treated hemi-parkinsonian rats anesthetized with isoflurane. This report describes new findings about how DA depletion alters MC-induced responses. MC stimulation evokes an excitation in normally quiescent striatal (Str) neurons projecting to the globus pallidus external segment (GPe). After DA-depletion, the spontaneous firing of Str-GPe neurons increases, and MC stimulation evokes a shorter latency excitation followed by a long-lasting inhibition that was invisible under normal conditions. The increased firing activity and the newly exposed long inhibition generate tonic inhibition and a disfacilitation in GPe. The disfacilitation in GPe is then amplified in basal ganglia circuitry and generates a powerful long inhibition in the basal ganglia output nucleus, the globus pallidus internal segment. Intra-Str injections of a behaviorally effective dose of DA precursor l-3,4-dihydroxyphenylalanine effectively reversed these changes. These newly observed mechanisms also support the generation of pauses and burst activity commonly observed in the basal ganglia of parkinsonian subjects. These results suggest that the generation of abnormal response sequences in the basal ganglia contributes to the development of motor disabilities in PD and that intra-Str DA supplements effectively suppress abnormal signal transfer.

Cold urticaria. Dissociation of cold-evoked histamine release and urticara following cold challenge.

Science.gov (United States)

Keahey, T M; Greaves, M W

1980-02-01

Nine patients with acquired cold urticaria were studied to assess the effects of beta-adrenergic agents, xanthines, and corticosteroids on cold-evoked histamine release from skin in vivo. The patients, in all of whom an immediate urticarial response developed after cooling of the forearm, demonstrated release of histamine into the venous blood draining that forearm. Following treatment with aminophylline and albuterol in combination or prednisone alone, suppression of histamine release occurred in all but one patient. In some patients, this was accompanied by a subjective diminution in pruritus or buring, but there was no significant improvement in the ensuing edema or erythema. In one patient, total suppression of histamine release was achieved without any effect on whealing and erythema in response to cold challenge. Our results suggest that histamine is not central to the pathogenesis of vascular changes in acquired cold urticaria.

Infrared neural stimulation (INS) inhibits electrically evoked neural responses in the deaf white cat

Science.gov (United States)

Richter, Claus-Peter; Rajguru, Suhrud M.; Robinson, Alan; Young, Hunter K.

2014-03-01

Infrared neural stimulation (INS) has been used in the past to evoke neural activity from hearing and partially deaf animals. All the responses were excitatory. In Aplysia californica, Duke and coworkers demonstrated that INS also inhibits neural responses [1], which similar observations were made in the vestibular system [2, 3]. In deaf white cats that have cochleae with largely reduced spiral ganglion neuron counts and a significant degeneration of the organ of Corti, no cochlear compound action potentials could be observed during INS alone. However, the combined electrical and optical stimulation demonstrated inhibitory responses during irradiation with infrared light.

Neuromagnetic Oscillations Predict Evoked-Response Latency Delays and Core Language Deficits in Autism Spectrum Disorders

Science.gov (United States)

Edgar, J. Christopher; Khan, Sarah Y.; Blaskey, Lisa; Chow, Vivian Y.; Rey, Michael; Gaetz, William; Cannon, Katelyn M.; Monroe, Justin F.; Cornew, Lauren; Qasmieh, Saba; Liu, Song; Welsh, John P.; Levy, Susan E.; Roberts, Timothy P. L.

2015-01-01

Previous studies have observed evoked response latency as well as gamma band superior temporal gyrus (STG) auditory abnormalities in individuals with autism spectrum disorders (ASD). A limitation of these studies is that associations between these two abnormalities, as well as the full extent of oscillatory phenomena in ASD in terms of frequency…

Elevating Endogenous GABA Levels with GAT-1 Blockade Modulates Evoked but Not Induced Responses in Human Visual Cortex

Science.gov (United States)

Muthukumaraswamy, Suresh D; Myers, Jim F M; Wilson, Sue J; Nutt, David J; Hamandi, Khalid; Lingford-Hughes, Anne; Singh, Krish D

2013-01-01

The electroencephalographic/magnetoencephalographic (EEG/MEG) signal is generated primarily by the summation of the postsynaptic currents of cortical principal cells. At a microcircuit level, these glutamatergic principal cells are reciprocally connected to GABAergic interneurons. Here we investigated the relative sensitivity of visual evoked and induced responses to altered levels of endogenous GABAergic inhibition. To do this, we pharmacologically manipulated the GABA system using tiagabine, which blocks the synaptic GABA transporter 1, and so increases endogenous GABA levels. In a single-blinded and placebo-controlled crossover study of 15 healthy participants, we administered either 15 mg of tiagabine or a placebo. We recorded whole-head MEG, while participants viewed a visual grating stimulus, before, 1, 3 and 5 h post tiagabine ingestion. Using beamformer source localization, we reconstructed responses from early visual cortices. Our results showed no change in either stimulus-induced gamma-band amplitude increases or stimulus-induced alpha amplitude decreases. However, the same data showed a 45% reduction in the evoked response component at ∼80 ms. These data demonstrate that, in early visual cortex the evoked response shows a greater sensitivity compared with induced oscillations to pharmacologically increased endogenous GABA levels. We suggest that previous studies correlating GABA concentrations as measured by magnetic resonance spectroscopy to gamma oscillation frequency may reflect underlying variations such as interneuron/inhibitory synapse density rather than functional synaptic GABA concentrations. PMID:23361120

Evoked acoustic emission

DEFF Research Database (Denmark)

Elberling, C; Parbo, J; Johnsen, N J

1985-01-01

Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has only...

Vascular responses to radiotherapy and androgen-deprivation therapy in experimental prostate cancer

International Nuclear Information System (INIS)

Røe, Kathrine; Mikalsen, Lars TG; Kogel, Albert J van der; Bussink, Johan; Lyng, Heidi; Ree, Anne H; Marignol, Laure; Olsen, Dag R

2012-01-01

Radiotherapy (RT) and androgen-deprivation therapy (ADT) are standard treatments for advanced prostate cancer (PC). Tumor vascularization is recognized as an important physiological feature likely to impact on both RT and ADT response, and this study therefore aimed to characterize the vascular responses to RT and ADT in experimental PC. Using mice implanted with CWR22 PC xenografts, vascular responses to RT and ADT by castration were visualized in vivo by DCE MRI, before contrast-enhancement curves were analyzed both semi-quantitatively and by pharmacokinetic modeling. Extracted image parameters were correlated to the results from ex vivo quantitative fluorescent immunohistochemical analysis (qIHC) of tumor vascularization (9 F1), perfusion (Hoechst 33342), and hypoxia (pimonidazole), performed on tissue sections made from tumors excised directly after DCE MRI. Compared to untreated (Ctrl) tumors, an improved and highly functional vascularization was detected in androgen-deprived (AD) tumors, reflected by increases in DCE MRI parameters and by increased number of vessels (VN), vessel density (VD), and vessel area fraction (VF) from qIHC. Although total hypoxic fractions (HF) did not change, estimated acute hypoxia scores (AHS) – the proportion of hypoxia staining within 50 μm from perfusion staining – were increased in AD tumors compared to in Ctrl tumors. Five to six months after ADT renewed castration-resistant (CR) tumor growth appeared with an even further enhanced tumor vascularization. Compared to the large vascular changes induced by ADT, RT induced minor vascular changes. Correlating DCE MRI and qIHC parameters unveiled the semi-quantitative parameters area under curve (AUC) from initial time-points to strongly correlate with VD and VF, whereas estimation of vessel size (VS) by DCE MRI required pharmacokinetic modeling. HF was not correlated to any DCE MRI parameter, however, AHS may be estimated after pharmacokinetic modeling. Interestingly, such

Objective assessment of spectral ripple discrimination in cochlear implant listeners using cortical evoked responses to an oddball paradigm.

Science.gov (United States)

Lopez Valdes, Alejandro; Mc Laughlin, Myles; Viani, Laura; Walshe, Peter; Smith, Jaclyn; Zeng, Fan-Gang; Reilly, Richard B

2014-01-01

Cochlear implants (CIs) can partially restore functional hearing in deaf individuals. However, multiple factors affect CI listener's speech perception, resulting in large performance differences. Non-speech based tests, such as spectral ripple discrimination, measure acoustic processing capabilities that are highly correlated with speech perception. Currently spectral ripple discrimination is measured using standard psychoacoustic methods, which require attentive listening and active response that can be difficult or even impossible in special patient populations. Here, a completely objective cortical evoked potential based method is developed and validated to assess spectral ripple discrimination in CI listeners. In 19 CI listeners, using an oddball paradigm, cortical evoked potential responses to standard and inverted spectrally rippled stimuli were measured. In the same subjects, psychoacoustic spectral ripple discrimination thresholds were also measured. A neural discrimination threshold was determined by systematically increasing the number of ripples per octave and determining the point at which there was no longer a significant difference between the evoked potential response to the standard and inverted stimuli. A correlation was found between the neural and the psychoacoustic discrimination thresholds (R2=0.60, p<0.01). This method can objectively assess CI spectral resolution performance, providing a potential tool for the evaluation and follow-up of CI listeners who have difficulty performing psychoacoustic tests, such as pediatric or new users.

Vascular Hyperpermeability Response in Animals Systemically Exposed to Arsenic.

Science.gov (United States)

Chen, Shih-Chieh; Chang, Chao-Yuah; Lin, Ming-Lu

2018-01-01

The mechanisms underlying cardiovascular diseases induced by chronic exposure to arsenic remain unclarified. The objectives of this study were to investigate whether increased vascular leakage is induced by inflammatory mustard oil in mice systemically exposed to various doses of arsenic and whether an increased vascular leakage response is still present in arsenic-fed mice after arsenic discontinuation for 2 or 6 months. ICR mice were fed water or various doses of sodium arsenite (10, 15, or 20 mg/kg/day; 5 days/week) for 8 weeks. In separate experiments, the mice were treated with sodium arsenite (20 mg/kg) for 2 or 8 weeks, followed by arsenic discontinuation for 2 or 6 months. Vascular permeability to inflammatory mustard oil was quantified using Evans blue (EB) techniques. Both arsenic-exposed and water-fed (control) mice displayed similar basal levels of EB leakage in the ears brushed with mineral oil, a vehicle of mustard oil. The levels of EB leakage induced by mustard oil in the arsenic groups fed with sodium arsenite (10 or 15 mg/kg) were similar to those of water-fed mice. However, increased levels of EB leakage in response to mustard oil stimulation were significantly higher in mice treated with sodium arsenite (20 mg/kg; high dose) than in arsenic-fed (10 or 15 mg/kg; low and middle doses) or control mice. After arsenic discontinuation for 2 or 6 months, mustard oil-induced vascular EB leakage in arsenic-fed (20 mg/kg) mice was similar to that in control mice. Dramatic increases in mustard oil-induced vascular leakage were only present in mice systemically exposed to the high arsenic dose, indicating the synergistic effects of the high arsenic dose and mustard oil.

Compression-induced hyperaemia in the rabbit masseter muscle: a model to investigate vascular mechano-sensitivity of skeletal muscle

International Nuclear Information System (INIS)

Turturici, Marco; Roatta, Silvestro

2013-01-01

Recent evidence suggests that the mechano-sensitivity of the vascular network may underlie rapid dilatory events in skeletal muscles. Previous investigations have been mostly based either on in vitro or on whole-limb studies, neither preparation allowing one to assess the musculo-vascular specificity under physiological conditions. The aim of this work is to characterize the mechano-sensitivity of an exclusively-muscular vascular bed in vivo. In five anesthetized rabbits, muscle blood flow was continuously monitored in the masseteric artery, bilaterally (n = 10). Hyperaemic responses were evoked by compressive stimuli of different extent (50, 100 and 200 mm Hg) and duration (0.5, 1, 2 and 5 s) exerted by a servo-controlled motor on the masseter muscle. Peak amplitude of the hyperaemic response ranged from 340 ± 30% of baseline (at 50 mm Hg) to 459 ± 57% (at 200 mm Hg) (P < 0.05), did not depend on stimulus duration and exhibited very good reliability (ICC = 0.98) when reassessed at 30 min intervals. The time course of the response depended neither on applied pressure nor on the duration of the stimulus. In conclusion, for its high sensitivity and reliability this technique is adequate to characterize mechano-vascular reactivity and may prove useful in the investigation of the underlying mechanisms, with implications in the control of vascular tone and blood pressure in health and disease. (paper)

Suppressive effects of lysozyme on polyphosphate-mediated vascular inflammatory responses

Energy Technology Data Exchange (ETDEWEB)

Chung, Jiwoo [College of Pharmacy, CMRI, Research Institute of Pharmaceutical Sciences, BK21 Plus KNU Multi-Omics Based Creative Drug Research Team, Kyungpook National University, Daegu 41566 (Korea, Republic of); Ku, Sae-Kwang [Department of Anatomy and Histology, College of Korean Medicine, Daegu Haany University, Gyeongsan 38610 (Korea, Republic of); Lee, Suyeon [College of Pharmacy, CMRI, Research Institute of Pharmaceutical Sciences, BK21 Plus KNU Multi-Omics Based Creative Drug Research Team, Kyungpook National University, Daegu 41566 (Korea, Republic of); Bae, Jong-Sup, E-mail: baejs@knu.ac.kr [College of Pharmacy, CMRI, Research Institute of Pharmaceutical Sciences, BK21 Plus KNU Multi-Omics Based Creative Drug Research Team, Kyungpook National University, Daegu 41566 (Korea, Republic of)

2016-06-10

Lysozyme, found in relatively high concentration in blood, saliva, tears, and milk, protects us from the ever-present danger of bacterial infection. Previous studies have reported proinflammatory responses of endothelial cells to the release of polyphosphate(PolyP). In this study, we examined the anti-inflammatory responses and mechanisms of lysozyme and its effects on PolyP-induced septic activities in human umbilical vein endothelial cells (HUVECs) and mice. The survival rates, septic biomarker levels, behavior of human neutrophils, and vascular permeability were determined in PolyP-activated HUVECs and mice. Lysozyme suppressed the PolyP-mediated vascular barrier permeability, upregulation of inflammatory biomarkers, adhesion/migration of leukocytes, and activation and/or production of nuclear factor-κB, tumor necrosis factor-α, and interleukin-6. Furthermore, lysozyme demonstrated protective effects on PolyP-mediated lethal death and the levels of the related septic biomarkers. Therefore, these results indicated the therapeutic potential of lysozyme on various systemic inflammatory diseases, such as sepsis or septic shock. -- Highlights: •PolyP is shown to be an important mediator of vascular inflammation. •Lysozyme inhibited PolyP-mediated hyperpermeability. •Lysozyme inhibited PolyP-mediated septic response. •Lysozyme reduced PolyP-induced septic mortality.

Suppressive effects of lysozyme on polyphosphate-mediated vascular inflammatory responses

International Nuclear Information System (INIS)

Chung, Jiwoo; Ku, Sae-Kwang; Lee, Suyeon; Bae, Jong-Sup

2016-01-01

Lysozyme, found in relatively high concentration in blood, saliva, tears, and milk, protects us from the ever-present danger of bacterial infection. Previous studies have reported proinflammatory responses of endothelial cells to the release of polyphosphate(PolyP). In this study, we examined the anti-inflammatory responses and mechanisms of lysozyme and its effects on PolyP-induced septic activities in human umbilical vein endothelial cells (HUVECs) and mice. The survival rates, septic biomarker levels, behavior of human neutrophils, and vascular permeability were determined in PolyP-activated HUVECs and mice. Lysozyme suppressed the PolyP-mediated vascular barrier permeability, upregulation of inflammatory biomarkers, adhesion/migration of leukocytes, and activation and/or production of nuclear factor-κB, tumor necrosis factor-α, and interleukin-6. Furthermore, lysozyme demonstrated protective effects on PolyP-mediated lethal death and the levels of the related septic biomarkers. Therefore, these results indicated the therapeutic potential of lysozyme on various systemic inflammatory diseases, such as sepsis or septic shock. -- Highlights: •PolyP is shown to be an important mediator of vascular inflammation. •Lysozyme inhibited PolyP-mediated hyperpermeability. •Lysozyme inhibited PolyP-mediated septic response. •Lysozyme reduced PolyP-induced septic mortality.

Refractory episodic vertigo: role of intratympanic gentamicin and vestibular evoked myogenic potentials,

Directory of Open Access Journals (Sweden)

Erika Celis-Aguilar

Full Text Available Abstract Introduction: Even today, the treatment of intractable vertigo remains a challenge. Vestibular ablation with intratympanic gentamicin stands as a good alternative in the management of refractory vertigo patients. Objective: To control intractable vertigo through complete saccular and horizontal canal vestibular ablation with intratympanic gentamicin treatment. Methods: Patients with refractory episodic vertigo were included. The inclusion criteria were: unilateral ear disease, moderate to profound sensorineural hearing loss, and failure to other treatments. Included patients underwent 0.5-0.8 mL of gentamicin intratympanic application at a 30 mg/mL concentration. Vestibular ablation was confirmed by the absence of response on cervical vestibular evoked myogenic potentials and no response on caloric tests. Audiometry, electronystagmography with iced water, and vestibular evoked myogenic potentials were performed in all patients. Results: Ten patients were included; nine patients with Meniere's disease and one patient with (late onset delayed hydrops. Nine patients showed an absent response on vestibular evoked myogenic potentials and no response on caloric tests. The only patient with low amplitude on cervical vestibular evoked myogenic potentials had vertigo recurrence. Vertigo control was achieved in 90% of the patients. One patient developed hearing loss >30 dB. Conclusions: Cervical vestibular evoked myogenic potentials confirmed vestibular ablation in patients treated with intratympanic gentamicin. High-grade vertigo control was due to complete saccular and horizontal canal ablation (no response to iced water in electronystagmography and no response on cervical vestibular evoked myogenic potentials.

Microvascular dysfunction with increased vascular leakage response in mice systemically exposed to arsenic.

Science.gov (United States)

Chen, Shih-Chieh; Huang, Shin-Yin; Lu, Chi-Yu; Hsu, Ya-Hung; Wang, Dean-Chuan

2014-09-01

The mechanisms underlying cardiovascular disease induced by arsenic exposure are not completely understood. The objectives of this study were to investigate whether arsenic-fed mice have an increased vascular leakage response to vasoactive agents and whether enhanced type-2 protein phosphatase (PP2A) activity is involved in mustard oil-induced leakage. ICR mice were fed water or sodium arsenite (20 mg/kg) for 4 or 8 weeks. The leakage response to vasoactive agents was quantified using the Evans blue (EB) technique or vascular labeling with carbon particles. Increased EB leakage and high density of carbon-labeled microvessels were detected in arsenic-fed mice treated with mustard oil. Histamine induced significantly higher vascular leakage in arsenic-fed mice than in water-fed mice. Pretreatment with the PP2A inhibitor okadaic acid or the neurokinin 1 receptor (NK1R) blocker RP67580 significantly reduced mustard oil-induced vascular leakage in arsenic-fed mice. The protein levels of PP2Ac and NK1R were similar in both groups. PP2A activity was significantly higher in the arsenic-fed mice compared with the control group. These findings indicate that microvessels generally respond to vasoactive agents, and that the increased PP2A activity is involved in mustard oil-induced vascular leakage in arsenic-fed mice. Arsenic may initiate endothelial dysfunction, resulting in vascular leakage in response to vasoactive agents.

Task-specific modulation of human auditory evoked responses in a delayed-match-to-sample task

Directory of Open Access Journals (Sweden)

Feng eRong

2011-05-01

Full Text Available In this study, we focus our investigation on task-specific cognitive modulation of early cortical auditory processing in human cerebral cortex. During the experiments, we acquired whole-head magnetoencephalography (MEG data while participants were performing an auditory delayed-match-to-sample (DMS task and associated control tasks. Using a spatial filtering beamformer technique to simultaneously estimate multiple source activities inside the human brain, we observed a significant DMS-specific suppression of the auditory evoked response to the second stimulus in a sound pair, with the center of the effect being located in the vicinity of the left auditory cortex. For the right auditory cortex, a non-invariant suppression effect was observed in both DMS and control tasks. Furthermore, analysis of coherence revealed a beta band (12 ~ 20 Hz DMS-specific enhanced functional interaction between the sources in left auditory cortex and those in left inferior frontal gyrus, which has been shown to involve in short-term memory processing during the delay period of DMS task. Our findings support the view that early evoked cortical responses to incoming acoustic stimuli can be modulated by task-specific cognitive functions by means of frontal-temporal functional interactions.

Short-term vascular hemodynamic responses to isometric exercise in young adults and in the elderly

NARCIS (Netherlands)

Hartog, R. (Renee); D. Bolignano (Davide); E.J.G. Sijbrands (Eric); Pucci, G. (Giacomo); F.U.S. Mattace Raso (Francesco)

2018-01-01

textabstractBackground: Vascular aging is known to induce progressive stiffening of the large elastic arteries, altering vascular hemodynamics under both rest and stress conditions. In this study, we aimed to investigate changes in vascular hemodynamics in response to isometric handgrip exercise

Dominance of layer-specific microvessel dilation in contrast-enhanced high-resolution fMRI: Comparison between hemodynamic spread and vascular architecture with CLARITY.

Science.gov (United States)

Poplawsky, Alexander John; Fukuda, Mitsuhiro; Kang, Bok-Man; Kim, Jae Hwan; Suh, Minah; Kim, Seong-Gi

2017-08-16

Contrast-enhanced cerebral blood volume-weighted (CBVw) fMRI response peaks are specific to the layer of evoked synaptic activity (Poplawsky et al., 2015), but the spatial resolution limit of CBVw fMRI is unknown. In this study, we measured the laminar spread of the CBVw fMRI evoked response in the external plexiform layer (EPL, 265 ± 65 μm anatomical thickness, mean ± SD, n = 30 locations from 5 rats) of the rat olfactory bulb during electrical stimulation of the lateral olfactory tract and examined its potential vascular source. First, we obtained the evoked CBVw fMRI responses with a 55 × 55 μm 2 in-plane resolution and a 500-μm thickness at 9.4 T, and found that the fMRI signal peaked predominantly in the inner half of EPL (136 ± 54 μm anatomical thickness). The mean full-width at half-maximum of these fMRI peaks was 347 ± 102 μm and the functional spread was approximately 100 or 200 μm when the effects of the laminar thicknesses of EPL or inner EPL were removed, respectively. Second, we visualized the vascular architecture of EPL from a different rat using a Clear Lipid-exchanged Anatomically Rigid Imaging/immunostaining-compatible Tissue hYdrogel (CLARITY)-based tissue preparation method and confocal microscopy. Microvascular segments with an outer diameter of limit of the fMRI spatial resolution is approximately the average length of 1-2 microvessel segments, which may be sufficient for examining sublaminar circuits. Copyright © 2017 Elsevier Inc. All rights reserved.

An Analysis of Responses to Defibrotide in the Pulmonary Vascular Bed of the Cat.

Science.gov (United States)

Kaye, Alan D; Skonieczny, Brendan D; Kaye, Aaron J; Harris, Zoey I; Luk, Eric J

2016-01-01

Defibrotide is a polydisperse mixture of single-stranded oligonucleotides with many pharmacologic properties and multiple actions on the vascular endothelium. Responses to defibrotide and other vasodepressor agents were evaluated in the pulmonary vascular bed of the cat under conditions of controlled pulmonary blood flow and constant left atrial pressure. Lobar arterial pressure was increased to a high steady level with the thromboxane A2 analog U-46619. Under increased-tone conditions, defibrotide caused dose-dependent decreases in lobar arterial pressure without altering systemic arterial and left atrial pressures. Responses to defibrotide were significantly attenuated after the administration of the cyclooxygenase inhibitor sodium meclofenamate. Responses to defibrotide were also significantly attenuated after the administration of both the adenosine 1 and 2 receptor antagonists 8-cyclopentyl-1,3-dimethylxanthine and 8-(3-chlorostyryl)caffeine. Responses to defibrotide were not altered after the administration of the vascular selective adenosine triphosphate-sensitive potassium channel blocker U-37883A, or after the administration of the nitric oxide synthase inhibitor L-N-(1-iminoethyl)-ornithine. These data show that defibrotide has significant vasodepressor activity in the pulmonary vascular bed of the cat. They also suggest that pulmonary vasodilator responses to defibrotide are partially dependent on both the activation of the cyclooxygenase enzyme and adenosine 1 and 2 receptor pathways and independent of the activation of adenosine triphosphate-sensitive potassium channels or the synthesis of nitric oxide in the pulmonary vascular bed of the cat.

Steady-state evoked potentials possibilities for mental-state estimation

Science.gov (United States)

Junker, Andrew M.; Schnurer, John H.; Ingle, David F.; Downey, Craig W.

1988-01-01

The use of the human steady-state evoked potential (SSEP) as a possible measure of mental-state estimation is explored. A method for evoking a visual response to a sum-of-ten sine waves is presented. This approach provides simultaneous multiple frequency measurements of the human EEG to the evoking stimulus in terms of describing functions (gain and phase) and remnant spectra. Ways in which these quantities vary with the addition of performance tasks (manual tracking, grammatical reasoning, and decision making) are presented. Models of the describing function measures can be formulated using systems engineering technology. Relationships between model parameters and performance scores during manual tracking are discussed. Problems of unresponsiveness and lack of repeatability of subject responses are addressed in terms of a need for loop closure of the SSEP. A technique to achieve loop closure using a lock-in amplifier approach is presented. Results of a study designed to test the effectiveness of using feedback to consciously connect humans to their evoked response are presented. Findings indicate that conscious control of EEG is possible. Implications of these results in terms of secondary tasks for mental-state estimation and brain actuated control are addressed.

Neural responses to nostalgia-evoking music modeled by elements of dynamic musical structure and individual differences in affective traits.

Science.gov (United States)

Barrett, Frederick S; Janata, Petr

2016-10-01

Nostalgia is an emotion that is most commonly associated with personally and socially relevant memories. It is primarily positive in valence and is readily evoked by music. It is also an idiosyncratic experience that varies between individuals based on affective traits. We identified frontal, limbic, paralimbic, and midbrain brain regions in which the strength of the relationship between ratings of nostalgia evoked by music and blood-oxygen-level-dependent (BOLD) signal was predicted by affective personality measures (nostalgia proneness and the sadness scale of the Affective Neuroscience Personality Scales) that are known to modulate the strength of nostalgic experiences. We also identified brain areas including the inferior frontal gyrus, substantia nigra, cerebellum, and insula in which time-varying BOLD activity correlated more strongly with the time-varying tonal structure of nostalgia-evoking music than with music that evoked no or little nostalgia. These findings illustrate one way in which the reward and emotion regulation networks of the brain are recruited during the experiencing of complex emotional experiences triggered by music. These findings also highlight the importance of considering individual differences when examining the neural responses to strong and idiosyncratic emotional experiences. Finally, these findings provide a further demonstration of the use of time-varying stimulus-specific information in the investigation of music-evoked experiences. Copyright © 2016 Elsevier Ltd. All rights reserved.

Refractory episodic vertigo: role of intratympanic gentamicin and vestibular evoked myogenic potentials.

Science.gov (United States)

Celis-Aguilar, Erika; Hinojosa-González, Ramon; Vales-Hidalgo, Olivia; Coutinho-Toledo, Heloisa

Even today, the treatment of intractable vertigo remains a challenge. Vestibular ablation with intratympanic gentamicin stands as a good alternative in the management of refractory vertigo patients. To control intractable vertigo through complete saccular and horizontal canal vestibular ablation with intratympanic gentamicin treatment. Patients with refractory episodic vertigo were included. The inclusion criteria were: unilateral ear disease, moderate to profound sensorineural hearing loss, and failure to other treatments. Included patients underwent 0.5-0.8mL of gentamicin intratympanic application at a 30mg/mL concentration. Vestibular ablation was confirmed by the absence of response on cervical vestibular evoked myogenic potentials and no response on caloric tests. Audiometry, electronystagmography with iced water, and vestibular evoked myogenic potentials were performed in all patients. Ten patients were included; nine patients with Meniere's disease and one patient with (late onset) delayed hydrops. Nine patients showed an absent response on vestibular evoked myogenic potentials and no response on caloric tests. The only patient with low amplitude on cervical vestibular evoked myogenic potentials had vertigo recurrence. Vertigo control was achieved in 90% of the patients. One patient developed hearing loss >30dB. Cervical vestibular evoked myogenic potentials confirmed vestibular ablation in patients treated with intratympanic gentamicin. High-grade vertigo control was due to complete saccular and horizontal canal ablation (no response to iced water in electronystagmography and no response on cervical vestibular evoked myogenic potentials). Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Predictive value of neurological examination for early cortical responses to somatosensory evoked potentials in patients with postanoxic coma

NARCIS (Netherlands)

Bouwes, Aline; Binnekade, Jan M.; Verbaan, Bart W.; Zandbergen, Eveline G. J.; Koelman, Johannes H. T. M.; Weinstein, Henry C.; Hijdra, Albert; Horn, Janneke

2012-01-01

Bilateral absence of cortical N20 responses of median nerve somatosensory evoked potentials (SEP) predicts poor neurological outcome in postanoxic coma after cardiopulmonary resuscitation (CPR). Although SEP is easy to perform and available in most hospitals, it is worthwhile to know how

Voluntary muscle activation and evoked volitional-wave responses as a function of torque.

Science.gov (United States)

Hight, Robert E; Quarshie, Alwyn T; Black, Christopher D

2018-08-01

This study employed a unique stimulation paradigm which allowed for the simultaneous assessment of voluntary activation levels (VA) via twitch-interpolation, and the evoked V-wave responses of the plantar flexors during submaximal and maximal contractions. Test-retest reliability was also examined. Fourteen participants repeated a stimulation protocol over four visits to assess VA and evoked V-wave amplitude across torque levels ranging from 20% to 100% MVC. MVC torque and EMG amplitude were also measured. VA increased nonlinearly with torque production and plateaued by 80% MVC. V-wave amplitude increased linearly from 20% to 100% MVC. There were no differences in any dependent variable across visits (p > 0.05). VA demonstrated moderate to substantial reliability across all torque levels (ICC = 0.76-0.91) while V-wave amplitude exhibited fair to moderate reliability from 40% to 100% (ICC = 0.48-0.74). We were able to reliably collect VA and the V-wave simultaneously in the plantar flexors. Collection of VA and V-wave during the same contraction provides distinct information regarding the contribution of motor-unit recruitment and descending cortico-spinal drive/excitability to force production. Copyright © 2018 Elsevier Ltd. All rights reserved.

Visual Evoked Response in Children Subjected to Prenatal Maternal ...

African Journals Online (AJOL)

neural conduction, or arousal level. S. Afr. Med. J., 48 ... pression treatment in either development or IQ, whether ... children in brain function at an electrophysiological level, ..... Perry, N. W. and Childers, D. G. (1969): The Human Visual Evoked.

Correlation between electrical and hemodynamic responses during visual stimulation with graded contrasts

Science.gov (United States)

Si, Juanning; Zhang, Xin; Li, Yuejun; Zhang, Yujin; Zuo, Nianming; Jiang, Tianzi

2016-09-01

Brain functional activity involves complex cellular, metabolic, and vascular chain reactions, making it difficult to comprehend. Electroencephalography (EEG) and functional near infrared spectroscopy (fNIRS) have been combined into a multimodal neuroimaging method that captures both electrophysiological and hemodynamic information to explore the spatiotemporal characteristics of brain activity. Because of the significance of visually evoked functional activity in clinical applications, numerous studies have explored the amplitude of the visual evoked potential (VEP) to clarify its relationship with the hemodynamic response. However, relatively few studies have investigated the influence of latency, which has been frequently used to diagnose visual diseases, on the hemodynamic response. Moreover, because the latency and the amplitude of VEPs have different roles in coding visual information, investigating the relationship between latency and the hemodynamic response should be helpful. In this study, checkerboard reversal tasks with graded contrasts were used to evoke visual functional activity. Both EEG and fNIRS were employed to investigate the relationship between neuronal electrophysiological activities and the hemodynamic responses. The VEP amplitudes were linearly correlated with the hemodynamic response, but the VEP latency showed a negative linear correlation with the hemodynamic response.

Evoked response of heart rate variability using short-duration white noise.

Science.gov (United States)

Lee, Guo-She; Chen, Mei-Ling; Wang, Gin-You

2010-06-24

To investigate and to establish a model for evaluation of the instant cardiovascular responses to the noises of low-to-moderate intensity, sixteen healthy subjects were enrolled. The white noises were binaurally presented with a supra-aural earphone. The test intensities of noises were no noise, 50, 60, 70 and 80 dBA. Each noise was continued for 5 min and the electrocardiogram was simultaneously recorded. The cardiac autonomic responses were evaluated using power spectral analysis of the R-R contour obtained from digital signal processing of the ECG tracings. The result showed that the mean heart rate and mean blood pressure did not change significantly with the noises. However, the low-frequency power (LF) which represents cardiac autonomic modulations and the ratio (LHR) of LF to high-frequency power (HF) which reflects cardiac sympathetic modulations were significantly greater in the noise intensity of 50, 60, 70 and 80dBA (pnoise intensity (rho=0.90, pwhite noises can be detected using power spectral analysis of heart rate variability and the evoked responses may provide a sensitive way to evaluate the instant effect of noise to humans.

Vascular Response of Ruthenium Tetraamines in Aortic Ring from Normotensive Rats

Directory of Open Access Journals (Sweden)

Ana Gabriela Conceição-Vertamatti

2015-03-01

Full Text Available Background: Ruthenium (Ru tetraamines are being increasingly used as nitric oxide (NO carriers. In this context, pharmacological studies have become highly relevant to better understand the mechanism of action involved. Objective: To evaluate the vascular response of the tetraamines trans-[RuII(NH34(Py(NO]3+, trans-[RuII(Cl(NO (cyclan](PF62, and trans-[RuII(NH34(4-acPy(NO]3+. Methods: Aortic rings were contracted with noradrenaline (10−6 M. After voltage stabilization, a single concentration (10−6 M of the compounds was added to the assay medium. The responses were recorded during 120 min. Vascular integrity was assessed functionally using acetylcholine at 10−6 M and sodium nitroprusside at 10−6 M as well as by histological examination. Results: Histological analysis confirmed the presence or absence of endothelial cells in those tissues. All tetraamine complexes altered the contractile response induced by norepinephrine, resulting in increased tone followed by relaxation. In rings with endothelium, the inhibition of endothelial NO caused a reduction of the contractile effect caused by pyridine NO. No significant responses were observed in rings with endothelium after treatment with cyclan NO. In contrast, in rings without endothelium, the inhibition of guanylate cyclase significantly reduced the contractile response caused by the pyridine NO and cyclan NO complexes, and both complexes caused a relaxing effect. Conclusion: The results indicate that the vascular effect of the evaluated complexes involved a decrease in the vascular tone induced by norepinephrine (10−6 M at the end of the incubation period in aortic rings with and without endothelium, indicating the slow release of NO from these complexes and suggesting that the ligands promoted chemical stability to the molecule. Moreover, we demonstrated that the association of Ru with NO is more stable when the ligands pyridine and cyclan are used in the formulation of the compound.

Cortical evoked potentials to an auditory illusion: binaural beats.

Science.gov (United States)

Pratt, Hillel; Starr, Arnold; Michalewski, Henry J; Dimitrijevic, Andrew; Bleich, Naomi; Mittelman, Nomi

2009-08-01

To define brain activity corresponding to an auditory illusion of 3 and 6Hz binaural beats in 250Hz or 1000Hz base frequencies, and compare it to the sound onset response. Event-Related Potentials (ERPs) were recorded in response to unmodulated tones of 250 or 1000Hz to one ear and 3 or 6Hz higher to the other, creating an illusion of amplitude modulations (beats) of 3Hz and 6Hz, in base frequencies of 250Hz and 1000Hz. Tones were 2000ms in duration and presented with approximately 1s intervals. Latency, amplitude and source current density estimates of ERP components to tone onset and subsequent beats-evoked oscillations were determined and compared across beat frequencies with both base frequencies. All stimuli evoked tone-onset P(50), N(100) and P(200) components followed by oscillations corresponding to the beat frequency, and a subsequent tone-offset complex. Beats-evoked oscillations were higher in amplitude with the low base frequency and to the low beat frequency. Sources of the beats-evoked oscillations across all stimulus conditions located mostly to left lateral and inferior temporal lobe areas in all stimulus conditions. Onset-evoked components were not different across stimulus conditions; P(50) had significantly different sources than the beats-evoked oscillations; and N(100) and P(200) sources located to the same temporal lobe regions as beats-evoked oscillations, but were bilateral and also included frontal and parietal contributions. Neural activity with slightly different volley frequencies from left and right ear converges and interacts in the central auditory brainstem pathways to generate beats of neural activity to modulate activities in the left temporal lobe, giving rise to the illusion of binaural beats. Cortical potentials recorded to binaural beats are distinct from onset responses. Brain activity corresponding to an auditory illusion of low frequency beats can be recorded from the scalp.

Low-intensity focused ultrasound alters the latency and spatial patterns of sensory-evoked cortical responses in vivo

Science.gov (United States)

Fisher, Jonathan A. N.; Gumenchuk, Iryna

2018-06-01

Objective. The use of transcranial, low intensity focused ultrasound (FUS) is an emerging neuromodulation technology that shows promise for both therapeutic and research applications. Among many, one of the most exciting applications is the use of FUS to rehabilitate or augment human sensory capabilities. While there is compelling empirical evidence demonstrating this capability, basic questions regarding the spatiotemporal extent of the modulatory effects remain. Our objective was to assess the basic, yet often overlooked hypothesis that FUS in fact alters sensory-evoked neural activity within the region of the cerebral cortex at the beam’s focus. Approach. To address this knowledge gap, we developed an approach to optically interrogate patterns of neural activity in the cortex directly at the acoustic focus, in vivo. Implementing simultaneous wide-field optical imaging and FUS stimulation in mice, our experiments probed somatosensory-evoked electrical activity through the use of voltage sensitive dyes (VSDs) and, in transgenic mice expressing GCaMP6f, monitored associated Ca2+ responses. Main results. Our results demonstrate that low-intensity FUS alters both the kinetics and spatial patterns of neural activity in primary somatosensory cortex at the acoustic focus. When preceded by 1 s of pulsed ultrasound at intensities below 1 W cm‑2 (I sppa), the onset of sensory-evoked cortical responses occurred 3.0  ±  0.7 ms earlier and altered the surface spatial morphology of Ca2+ responses. Significance. These findings support the heretofore unconfirmed assumption that FUS-induced sensory modulation reflects, at least in part, altered reactivity in primary sensory cortex at the site of sonication. The findings are significant given the interest in using FUS to target and alter spatial aspects of sensory receptive fields on the cerebral cortex.

Low-intensity focused ultrasound alters the latency and spatial patterns of sensory-evoked cortical responses in vivo.

Science.gov (United States)

Fisher, Jonathan A N; Gumenchuk, Iryna

2018-02-13

The use of transcranial, low intensity focused ultrasound (FUS) is an emerging neuromodulation technology that shows promise for both therapeutic and research applications. Among many, one of the most exciting applications is the use of FUS to rehabilitate or augment human sensory capabilities. While there is compelling empirical evidence demonstrating this capability, basic questions regarding the spatiotemporal extent of the modulatory effects remain. Our objective was to assess the basic, yet often overlooked hypothesis that FUS in fact alters sensory-evoked neural activity within the region of the cerebral cortex at the beam's focus. To address this knowledge gap, we developed an approach to optically interrogate patterns of neural activity in the cortex directly at the acoustic focus, in vivo. Implementing simultaneous wide-field optical imaging and FUS stimulation in mice, our experiments probed somatosensory-evoked electrical activity through the use of voltage sensitive dyes (VSDs) and, in transgenic mice expressing GCaMP6f, monitored associated Ca 2+ responses. Our results demonstrate that low-intensity FUS alters both the kinetics and spatial patterns of neural activity in primary somatosensory cortex at the acoustic focus. When preceded by 1 s of pulsed ultrasound at intensities below 1 W cm -2 (I sppa ), the onset of sensory-evoked cortical responses occurred 3.0  ±  0.7 ms earlier and altered the surface spatial morphology of Ca 2+ responses. These findings support the heretofore unconfirmed assumption that FUS-induced sensory modulation reflects, at least in part, altered reactivity in primary sensory cortex at the site of sonication. The findings are significant given the interest in using FUS to target and alter spatial aspects of sensory receptive fields on the cerebral cortex.

Scent-evoked nostalgia.

Science.gov (United States)

Reid, Chelsea A; Green, Jeffrey D; Wildschut, Tim; Sedikides, Constantine

2015-01-01

Can scents evoke nostalgia; what might be the psychological implications of such an evocation? Participants sampled 12 scents and rated the extent to which each scent was familiar, arousing and autobiographically relevant, as well as the extent to which each scent elicited nostalgia. Participants who were high (compared to low) in nostalgia proneness reported more scent-evoked nostalgia, and scents elicited greater nostalgia to the extent that they were arousing, familiar and autobiographically relevant. Scent-evoked nostalgia predicted higher levels of positive affect, self-esteem, self-continuity, optimism, social connectedness and meaning in life. In addition, scent-evoked nostalgia was characterised by more positive emotions than either non-nostalgic autobiographical memories or non-nostalgic non-autobiographical memories. Finally, scent-evoked nostalgia predicted in-the-moment feelings of personal (general or object-specific) nostalgia. The findings represent a foray into understanding the triggers and affective signature of scent-evoked nostalgia.

Changes in forearm muscle temperature alter renal vascular responses to isometric handgrip.

Science.gov (United States)

Kuipers, Nathan T; Sauder, Charity L; Kearney, Matthew L; Ray, Chester A

2007-12-01

The purpose of the present study was to examine the effect of heating and cooling the forearm muscles on renal vascular responses to ischemic isometric handgrip (IHG). It was hypothesized that heating and cooling the forearm would augment and attenuate, respectively, renal vascular responses to IHG. Renal vascular responses to IHG were studied during forearm heating at 39 degrees C (n = 15, 26 +/- 1 yr) and cooling at 26 degrees C (n = 12, 26 +/- 1 yr). For a control trial, subjects performed the experimental protocol while the forearm was normothermic (approximately 34 degrees C). Muscle temperature (measured by intramuscular probe) was controlled by changing the temperature of water cycling through a water-perfused sleeve. The experimental protocol was as follows: 3 min at baseline, 1 min of ischemia, ischemic IHG to fatigue, and 2 min of postexercise muscle ischemia. At rest, renal artery blood velocity (RBV; Doppler ultrasound) and renal vascular conductance (RVC = RBV/mean arterial blood pressure) were not different between normothermia and the two thermal conditions. During ischemic IHG, there were greater decreases in RBV and RVC in the heating trial. However, RBV and RVC were similar during postexercise muscle ischemia during heating and normothermia. RVC decreased less during cooling than in normothermia while the subjects performed the ischemic IHG protocol. During postexercise muscle ischemia, RVC was greater during cooling than in normothermia. These results indicate that heating augments mechanoreceptor-mediated renal vasoconstriction whereas cooling blunts metaboreceptor-mediated renal vasoconstriction.

Behavioral analyses of wind-evoked escape of the cricket, Gryllodes sigillatus.

Science.gov (United States)

Kanou, Masamichi; Konishi, Atsuko; Suenaga, Rie

2006-04-01

The wind-evoked escape behavior of the cricket Gryllodes sigillatus was investigated using an air puff stimulus. A high velocity air puff elicited the escape behavior in many crickets. The crickets tended to escape away from the stimulus source, but the direction was not accurately oriented 180 degrees from the stimulus. After bilateral cercal ablation, only a few crickets showed wind-evoked escape behavior, and their response rates did not increase even 19 days after ablation. Therefore, information on air motion detected by cercal filiform hairs is essential for triggering wind-evoked behavior. After unilateral cercal ablation, the 81.3% response rate of intact crickets decreased to 16.5%, that is, it decreased to almost 20% that of intact crickets. One week after unilateral cercal ablation, the response rate recovered to more than 60% that of intact crickets. However, the accuracy rate of the escape direction of G. sigillatus showed no change even immediately after the unilateral cercal ablation. Therefore, both cerci are not necessarily required to determine the escape direction. The behavioral characteristics of wind-evoked escape of G. sigillatus are compared with those of another species of cricket, Gryllus bimaculatus. The two species of cricket employ different strategies for wind-evoked escape.

Middle components of the auditory evoked response in bilateral temporal lobe lesions. Report on a patient with auditory agnosia

DEFF Research Database (Denmark)

Parving, A; Salomon, G; Elberling, Claus

1980-01-01

An investigation of the middle components of the auditory evoked response (10--50 msec post-stimulus) in a patient with auditory agnosia is reported. Bilateral temporal lobe infarctions were proved by means of brain scintigraphy, CAT scanning, and regional cerebral blood flow measurements...

Vibration and muscle contraction affect somatosensory evoked potentials

OpenAIRE

Cohen, LG; Starr, A

1985-01-01

We recorded potentials evoked by specific somatosensory stimuli over peripheral nerve, spinal cord, and cerebral cortex. Vibration attenuated spinal and cerebral potentials evoked by mixed nerve and muscle spindle stimulation; in one subject that was tested, there was no effect on cutaneous input. Presynaptic inhibition of Ia input in the spinal cord and muscle spindle receptor occupancy are probably the responsible mechanisms. In contrast, muscle contraction attenuated cerebral potentials to...

Habituation of evoked responses is greater in patients with familial hemiplegic migraine than in controls

DEFF Research Database (Denmark)

Hansen, Jakob Møller; Bolla, M; Magis, D

2011-01-01

have associated with disturbed ion homeostasis, altered cellular excitability, neurotransmitter release, and decreased threshold for cortical spreading depression. The common forms of migraine are characterized interictally by a habituation deficit of cortical and subcortical evoked responses that has...... been attributed to neuronal dysexcitability. FHM and the common forms of migraine are thought to belong to a spectrum of migraine phenotypes with similar pathophysiology, and we therefore examined whether an abnormal habituation pattern would also be found in FHM patients....

Effect of nabumetone treatment on vascular responses of the thoracic aorta in rat experimental arthritis.

Science.gov (United States)

Ulker, S; Onal, A; Hatip, F B; Sürücü, A; Alkanat, M; Koşay, S; Evinç, A

2000-04-01

Nabumetone is a nonsteroidal anti-inflammatory (NSAI) drug which is known to cause less gastrointestinal damage than other NSAI drugs. This study was performed to evaluate whether nabumetone treatment might alter the vascular aberrations related to inflammation in a rat model of adjuvant-induced arthritis. Nabumetone treatment (120 or 240 mg x kg(-1) x day(-1), orally) was initiated on the 15th day of adjuvant inoculation and continued for 14 days. Arthritic lesions, vascular contractile and relaxant responses and gastroduodenal histopathological preparations were evaluated 29 days after adjuvant inoculation. The contractile responses of aortic rings to phenylephrine and KCl were increased in grade 2 arthritic rats. In grade 3 arthritis only the phenylephrine contractility was decreased. The relaxant responses to acetylcholine and sodium nitroprusside were decreased in grades 2 and 3. In healthy rats, nabumetone did not change the vascular responses. After treatment of arthritic rats with nabumetone, both the contractile and relaxant response of the aortic rings returned to normal, and arthritic score and paw swelling were reduced. Gastroduodenal histopathology did not show erosions or ulcers in any of the groups. In conclusion, nabumetone improved the systemic signs and vascular alterations in experimental arthritis without showing any gastrointestinal side effects. Copyright 2000 S. Karger AG, Basel.

Regularity increases middle latency evoked and late induced beta brain response following proprioceptive stimulation

DEFF Research Database (Denmark)

Arnfred, Sidse M.; Hansen, Lars Kai; Parnas, Josef

2008-01-01

as an indication of increased readiness. This is achieved through detailed analysis of both evoked and induced responses in the time-frequency domain. Electroencephalography in a 64 channels montage was recorded in four-teen healthy subjects. Two paradigms were explored: A Regular alternation between hand......). After initial exploration of the AvVVT and Induced collapsed files of all subjects using two-way factor analyses (Non-Negative Matrix Factorization), further data decomposition was performed in restricted windows of interest (WOI). Main effects of side of stimulation, onset or offset, regularity...

Endurance exercise training increases peripheral vascular response in human fingers.

Science.gov (United States)

Katayama, K; Shimoda, M; Maeda, J; Takemiya, T

1998-10-01

The purpose of this study was to clarify whether peripheral vascular response to alteration of transmural pressure is changed by endurance exercise training. The healthy male subjects (training group; n = 6) performed endurance exercise training that consisted of cycle ergometer exercise 5 d.week-1 and 30 min.d-1 for a period of 8 weeks. Changes in the peripheral vascular response to alteration of transmural pressure in the human finger were measured by a differential digital photoplethysmogram (DeltaDPG) and blood pressure during passive movement of the arm to different vertical hand positions relative to heart level. Following 8 weeks of endurance training, percent changes in DeltaDPG from heart level in the training group increased significantly (mean +/- SD, -48.1 +/- 7. 3 to -58.7 +/- 9.3% at the lowered position, 46.1 +/- 13.4 to 84.6 +/- 8.8% at the elevated position, ppressure, also significantly changed in the training group over the 8 weeks (5.6 +/- 1.3 to 2.7 +/- 1.6 mV. V-1.s-1.mmHg-1 at the lowered position, 30.0 +/- 12.4 to 54.4 +/- 18. 9 mV.V-1.s-1.mmHg-1 at the elevated position ). Maximal oxygen uptake (V.O2 max) was significantly increased in the training group. On the other hand, the control group (n = 6) showed no significant changes in all parameters for 8 weeks. Therefore these results suggest that endurance exercise training induces an increase in peripheral vascular response to alteration of transmural pressure in the human finger.

Recording visual evoked potentials and auditory evoked P300 at 9.4T static magnetic field.

Science.gov (United States)

Arrubla, Jorge; Neuner, Irene; Hahn, David; Boers, Frank; Shah, N Jon

2013-01-01

Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) has shown a number of advantages that make this multimodal technique superior to fMRI alone. The feasibility of recording EEG at ultra-high static magnetic field up to 9.4 T was recently demonstrated and promises to be implemented soon in fMRI studies at ultra high magnetic fields. Recording visual evoked potentials are expected to be amongst the most simple for simultaneous EEG/fMRI at ultra-high magnetic field due to the easy assessment of the visual cortex. Auditory evoked P300 measurements are of interest since it is believed that they represent the earliest stage of cognitive processing. In this study, we investigate the feasibility of recording visual evoked potentials and auditory evoked P300 in a 9.4 T static magnetic field. For this purpose, EEG data were recorded from 26 healthy volunteers inside a 9.4 T MR scanner using a 32-channel MR compatible EEG system. Visual stimulation and auditory oddball paradigm were presented in order to elicit evoked related potentials (ERP). Recordings made outside the scanner were performed using the same stimuli and EEG system for comparison purposes. We were able to retrieve visual P100 and auditory P300 evoked potentials at 9.4 T static magnetic field after correction of the ballistocardiogram artefact using independent component analysis. The latencies of the ERPs recorded at 9.4 T were not different from those recorded at 0 T. The amplitudes of ERPs were higher at 9.4 T when compared to recordings at 0 T. Nevertheless, it seems that the increased amplitudes of the ERPs are due to the effect of the ultra-high field on the EEG recording system rather than alteration in the intrinsic processes that generate the electrophysiological responses.

Effect of gabazine on sensory stimulation train evoked response in mouse cerebellar Purkinje cells.

Science.gov (United States)

Bing, Yan-Hua; Jin, Wen-Zhe; Sun, Lei; Chu, Chun-Ping; Qiu, De-Lai

2015-02-01

Cerebellar Purkinje cells (PCs) respond to sensory stimulation via climbing fiber and mossy fiber-granule cell pathways, and generate motor-related outputs according to internal rules of integration and computation. However, the dynamic properties of sensory information processed by PC in mouse cerebellar cortex are currently unclear. In the present study, we examined the effects of the gamma-aminobutyric acid receptor A (GABA(A)) antagonist, gabazine, on the stimulation train on the simple spike firing of PCs by electrophysiological recordings method. Our data showed that the output of cerebellar PCs could be significantly affected by all pulses of the low-frequency (0.25 -2 Hz) sensory stimulation train, but only by the 1st and 2nd pulses of the high-frequency (≥ 4 Hz) sensory stimulation train. In the presence of gabazine (20 μM), each pulse of 1 Hz facial stimulation evoked simple spike firing in the PCs, but only the 1st and 2nd pulses of 4 Hz stimulation induced an increase in simple spike firing of the PCs. These results indicated that GABAA receptor-mediated inhibition did not significantly affect the frequency properties of sensory stimulation evoked responses in the mouse cerebellar PCs.

Suicide attempts, platelet monoamine oxidase and the average evoked response

International Nuclear Information System (INIS)

Buchsbaum, M.S.; Haier, R.J.; Murphy, D.L.

1977-01-01

The relationship between suicides and suicide attempts and two biological measures, platelet monoamine oxidase levels (MAO) and average evoked response (AER) augmenting was examined in 79 off-medication psychiatric patients and in 68 college student volunteers chosen from the upper and lower deciles of MAO activity levels. In the patient sample, male individuals with low MAO and AER augmenting, a pattern previously associated with bipolar affective disorders, showed a significantly increased incidence of suicide attempts in comparison with either non-augmenting low MAO or high MAO patients. Within the normal volunteer group, all male low MAO probands with a family history of suicide or suicide attempts were AER augmenters themselves. Four completed suicides were found among relatives of low MAO probands whereas no high MAO proband had a relative who committed suicide. These findings suggest that the combination of low platelet MAO activity and AER augmenting may be associated with a possible genetic vulnerability to psychiatric disorders. (author)

Auditory brainstem activity and development evoked by apical versus basal cochlear implant electrode stimulation in children.

Science.gov (United States)

Gordon, K A; Papsin, B C; Harrison, R V

2007-08-01

The role of apical versus basal cochlear implant electrode stimulation on central auditory development was examined. We hypothesized that, in children with early onset deafness, auditory development evoked by basal electrode stimulation would differ from that evoked more apically. Responses of the auditory nerve and brainstem, evoked by an apical and a basal implant electrode, were measured over the first year of cochlear implant use in 50 children with early onset severe to profound deafness who used hearing aids prior to implantation. Responses at initial stimulation were of larger amplitude and shorter latency when evoked by the apical electrode. No significant effects of residual hearing or age were found on initial response amplitudes or latencies. With implant use, responses evoked by both electrodes showed decreases in wave and interwave latencies reflecting decreased neural conduction time through the brainstem. Apical versus basal differences persisted with implant experience with one exception; eIII-eV interlatency differences decreased with implant use. Acute stimulation shows prolongation of basally versus apically evoked auditory nerve and brainstem responses in children with severe to profound deafness. Interwave latencies reflecting neural conduction along the caudal and rostral portions of the brainstem decreased over the first year of implant use. Differences in neural conduction times evoked by apical versus basal electrode stimulation persisted in the caudal but not rostral brainstem. Activity-dependent changes of the auditory brainstem occur in response to both apical and basal cochlear implant electrode stimulation.

Neurovascular Saturation Thresholds Under High Intensity Auditory Stimulation During Wake

Science.gov (United States)

Schei, Jennifer L.; Van Nortwick, Amy S.; Meighan, Peter C.; Rector, David M.

2012-01-01

Coupling between neural activity and hemodynamic responses is important in understanding brain function, interpreting brain imaging signals, and assessing pathological conditions. Tissue state is a major factor in neurovascular coupling and may alter the relationship between neural and hemodynamic activity. However, most neurovascular coupling studies are performed under anesthetized or sedated states which may have severe consequences on coupling mechanisms. Our previous studies showed that following prolonged periods of sleep deprivation, evoked hemodynamic responses were muted despite consistent electrical responses, suggesting that sustained neural activity may decrease vascular compliance and limit blood perfusion. To investigate potential perfusion limitations during natural waking conditions, we simultaneously measured evoked response potentials (ERPs) and evoked hemodynamic responses using optical imaging techniques to increasing intensity auditory stimulation. The relationship between evoked hemodynamic responses and integrated ERPs followed a sigmoid relationship where the hemodynamic response approached saturation at lower stimulus intensities than the ERP. If limits in blood perfusion are caused by stretching of the vessel wall, then these results suggest there may be decreased vascular compliance due to sustained neural activity during wake, which could limit vascular responsiveness and local blood perfusion. Conditions that stress cerebral vasculature, such as sleep deprivation and some pathologies (e.g., epilepsy), may further decrease vascular compliance, limit metabolic delivery, and cause tissue trauma. While ERPs and evoked hemodynamic responses provide an indication of the correlated neural activity and metabolic demand, the relationship between these two responses is complex and the different measurement techniques are not directly correlated. Future studies are required to verify these findings and further explore neurovascular coupling during

Brainstem evoked potentials in infantile spasms

International Nuclear Information System (INIS)

Miyazaki, Masahito; Hashimoto, Toshiaki; Murakawa, Kazuyoshi; Tayama, Masanobu; Kuroda, Yasuhiro

1992-01-01

In ten patients with infantile spasms, brainstem evoked potentials and MRI examinations were performed to evaluate the brainstem involvement. The result of short latency somatosensory evoked potentials (SSEP) following the right median nerve stimulation revealed abnormal findings including the absence or low amplitudes of the waves below wave P3 and delayed central conduction time in 7 of the ten patients. The result of auditory brainstem responses (ABR) revealed abnormal findings including low amplitudes of wave V, prolonged interpeak latency of waves I-V and absence of the waves below wave IV in 5 of the ten patients. The result of the MRI examinations revealed various degrees of the brainstem atrophy in 6 of the ten patients, all of whom showed abnormal brainstem evoked potentials. The result of this study demonstrates that patients with infantile spasms are frequently associated with brainstem dysfunction and raises the possibility that brainstem atrophy might be a cause of infantile spasms. (author)

Measures of total stress-induced blood pressure responses are associated with vascular damage.

Science.gov (United States)

Nazzaro, Pietro; Seccia, Teresa; Vulpis, Vito; Schirosi, Gabriella; Serio, Gabriella; Battista, Loredana; Pirrelli, Anna

2005-09-01

The role of cardiovascular reactivity to study hypertension, and the assessment methods, are still controversial. We aimed to verify the association of hypertension and vascular damage with several measures of cardiovascular response. We studied 40 patients with normal-high (132 +/- 1/87 +/- 1 mm Hg) blood pressure (Group 1) and 80 untreated hypertensive subjects. Postischemic forearm vascular resistance (mFVR) served to differentiate hypertensive subjects (142 +/- 2/92 +/- 1 mm Hg v 143 +/- 2/94 +/- 2 mm Hg, P = NS) with a lower (Group 2) and higher (Group 3) hemodynamic index of vascular damage (4.8 +/- .05 v 6.3 +/- .09, P blood pressure, heart rate, forearm blood flow, and vascular resistance. Reactivity measures included: a) change from baseline, b) residualized score, c) cumulative change from baseline and residualized score, and d) total reactivity as area-under-the-curve (AUC), including changes occurring during baseline and recovery phases. The AUC of systolic blood pressure, diastolic blood pressure, and mFVR progressively increased in the groups (P AUC of SBP, DBP, and forearm blood flow and resistance demonstrated the highest (P AUC of SBP (beta = 0.634) and forearm blood flow (beta = -0.337) were predictive (P blood pressure stress response, as AUC, including baseline and recovery phases, was significantly better associated with hypertension and vascular damage than the other reactivity measures studied.

An Idle-State Detection Algorithm for SSVEP-Based Brain-Computer Interfaces Using a Maximum Evoked Response Spatial Filter.

Science.gov (United States)

Zhang, Dan; Huang, Bisheng; Wu, Wei; Li, Siliang

2015-11-01

Although accurate recognition of the idle state is essential for the application of brain-computer interfaces (BCIs) in real-world situations, it remains a challenging task due to the variability of the idle state. In this study, a novel algorithm was proposed for the idle state detection in a steady-state visual evoked potential (SSVEP)-based BCI. The proposed algorithm aims to solve the idle state detection problem by constructing a better model of the control states. For feature extraction, a maximum evoked response (MER) spatial filter was developed to extract neurophysiologically plausible SSVEP responses, by finding the combination of multi-channel electroencephalogram (EEG) signals that maximized the evoked responses while suppressing the unrelated background EEGs. The extracted SSVEP responses at the frequencies of both the attended and the unattended stimuli were then used to form feature vectors and a series of binary classifiers for recognition of each control state and the idle state were constructed. EEG data from nine subjects in a three-target SSVEP BCI experiment with a variety of idle state conditions were used to evaluate the proposed algorithm. Compared to the most popular canonical correlation analysis-based algorithm and the conventional power spectrum-based algorithm, the proposed algorithm outperformed them by achieving an offline control state classification accuracy of 88.0 ± 11.1% and idle state false positive rates (FPRs) ranging from 7.4 ± 5.6% to 14.2 ± 10.1%, depending on the specific idle state conditions. Moreover, the online simulation reported BCI performance close to practical use: 22.0 ± 2.9 out of the 24 control commands were correctly recognized and the FPRs achieved as low as approximately 0.5 event/min in the idle state conditions with eye open and 0.05 event/min in the idle state condition with eye closed. These results demonstrate the potential of the proposed algorithm for implementing practical SSVEP BCI systems.

Sympathetic responses during saline infusion into the veins of an occluded limb.

Science.gov (United States)

Cui, Jian; McQuillan, Patrick; Moradkhan, Raman; Pagana, Charles; Sinoway, Lawrence I

2009-07-15

Animal studies have shown that the increased intravenous pressure stimulates the group III and IV muscle afferent fibres, and in turn induce cardiovascular responses. However, this pathway of autonomic regulation has not been examined in humans. The aim of this study was to examine the hypothesis that infusion of saline into the venous circulation of an arterially occluded vascular bed evokes sympathetic activation in healthy individuals. Blood pressure, heart rate, and muscle sympathetic nerve activity (MSNA) responses were assessed in 19 young healthy subjects during local infusion of 40 ml saline into a forearm vein in the circulatory arrested condition. From baseline (11.8 +/- 1.2 bursts min(-1)), MSNA increased significantly during the saline infusion (22.5 +/- 2.6 bursts min(-1), P Blood pressure also increased significantly during the saline infusion. Three control trials were performed during separate visits. The results from the control trial show that the observed MSNA and blood pressure responses were not due to muscle ischaemia. The present data show that saline infusion into the venous circulation of an arterially occluded vascular bed induces sympathetic activation and an increase in blood pressure. We speculate that the infusion under such conditions stimulates the afferent endings near the vessels, and evokes the sympathetic activation.

Brain-immune interaction accompanying odor-evoked autobiographic memory.

Science.gov (United States)

Matsunaga, Masahiro; Bai, Yu; Yamakawa, Kaori; Toyama, Asako; Kashiwagi, Mitsuyoshi; Fukuda, Kazuyuki; Oshida, Akiko; Sanada, Kazue; Fukuyama, Seisuke; Shinoda, Jun; Yamada, Jitsuhiro; Sadato, Norihiro; Ohira, Hideki

2013-01-01

The phenomenon in which a certain smell evokes a specific memory is known as the Proust phenomenon. Odor-evoked autobiographic memories are more emotional than those elicited by other sensory stimuli. The results of our previous study indicated that odor-evoked autobiographic memory accompanied by positive emotions has remarkable effects on various psychological and physiological activities, including the secretion of cytokines, which are immune-signaling molecules that modulate systemic inflammation. In this study, we aimed to clarify the neural substrates associated with the interaction between odor-evoked autobiographic memory and peripheral circulating cytokines. We recruited healthy male and female volunteers and investigated the association between brain responses and the concentration of several cytokines in the plasma by using positron emission tomography (PET) recordings when an autographic memory was evoked in participants by asking them to smell an odor that was nostalgic to them. Participants experienced positive emotions and autobiographic memories when nostalgic odors were presented to them. The levels of peripheral proinflammatory cytokines, such as the tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), were significantly reduced after experiencing odor-evoked autobiographic memory. Subtraction analysis of PET images indicated that the medial orbitofrontal cortex (mOFC) and precuneus/posterior cingulate cortex (PCC) were significantly activated during experiences of odor-evoked autobiographic memory. Furthermore, a correlation analysis indicated that activities of the mOFC and precuneus/PCC were negatively correlated with IFN-γ concentration. These results indicate that the neural networks including the precuneus/PCC and mOFC might regulate the secretion of peripheral proinflammatory cytokines during the experience of odor-evoked autobiographic memories accompanied with positive emotions.

Brain–Immune Interaction Accompanying Odor-Evoked Autobiographic Memory

Science.gov (United States)

Matsunaga, Masahiro; Bai, Yu; Yamakawa, Kaori; Toyama, Asako; Kashiwagi, Mitsuyoshi; Fukuda, Kazuyuki; Oshida, Akiko; Sanada, Kazue; Fukuyama, Seisuke; Shinoda, Jun; Yamada, Jitsuhiro; Sadato, Norihiro; Ohira, Hideki

2013-01-01

The phenomenon in which a certain smell evokes a specific memory is known as the Proust phenomenon. Odor-evoked autobiographic memories are more emotional than those elicited by other sensory stimuli. The results of our previous study indicated that odor-evoked autobiographic memory accompanied by positive emotions has remarkable effects on various psychological and physiological activities, including the secretion of cytokines, which are immune-signaling molecules that modulate systemic inflammation. In this study, we aimed to clarify the neural substrates associated with the interaction between odor-evoked autobiographic memory and peripheral circulating cytokines. We recruited healthy male and female volunteers and investigated the association between brain responses and the concentration of several cytokines in the plasma by using positron emission tomography (PET) recordings when an autographic memory was evoked in participants by asking them to smell an odor that was nostalgic to them. Participants experienced positive emotions and autobiographic memories when nostalgic odors were presented to them. The levels of peripheral proinflammatory cytokines, such as the tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), were significantly reduced after experiencing odor-evoked autobiographic memory. Subtraction analysis of PET images indicated that the medial orbitofrontal cortex (mOFC) and precuneus/posterior cingulate cortex (PCC) were significantly activated during experiences of odor-evoked autobiographic memory. Furthermore, a correlation analysis indicated that activities of the mOFC and precuneus/PCC were negatively correlated with IFN-γ concentration. These results indicate that the neural networks including the precuneus/PCC and mOFC might regulate the secretion of peripheral proinflammatory cytokines during the experience of odor-evoked autobiographic memories accompanied with positive emotions. PMID:23977312

Brain-immune interaction accompanying odor-evoked autobiographic memory.

Directory of Open Access Journals (Sweden)

Masahiro Matsunaga

Full Text Available The phenomenon in which a certain smell evokes a specific memory is known as the Proust phenomenon. Odor-evoked autobiographic memories are more emotional than those elicited by other sensory stimuli. The results of our previous study indicated that odor-evoked autobiographic memory accompanied by positive emotions has remarkable effects on various psychological and physiological activities, including the secretion of cytokines, which are immune-signaling molecules that modulate systemic inflammation. In this study, we aimed to clarify the neural substrates associated with the interaction between odor-evoked autobiographic memory and peripheral circulating cytokines. We recruited healthy male and female volunteers and investigated the association between brain responses and the concentration of several cytokines in the plasma by using positron emission tomography (PET recordings when an autographic memory was evoked in participants by asking them to smell an odor that was nostalgic to them. Participants experienced positive emotions and autobiographic memories when nostalgic odors were presented to them. The levels of peripheral proinflammatory cytokines, such as the tumor necrosis factor-α (TNF-α and interferon-γ (IFN-γ, were significantly reduced after experiencing odor-evoked autobiographic memory. Subtraction analysis of PET images indicated that the medial orbitofrontal cortex (mOFC and precuneus/posterior cingulate cortex (PCC were significantly activated during experiences of odor-evoked autobiographic memory. Furthermore, a correlation analysis indicated that activities of the mOFC and precuneus/PCC were negatively correlated with IFN-γ concentration. These results indicate that the neural networks including the precuneus/PCC and mOFC might regulate the secretion of peripheral proinflammatory cytokines during the experience of odor-evoked autobiographic memories accompanied with positive emotions.

Age-related hearing loss in dogs : Diagnosis with Brainstem-Evoked Response Audiometry and Treatment with Vibrant Soundbridge Middle Ear Implant.

NARCIS (Netherlands)

ter Haar, G.

2009-01-01

Age-related hearing loss (ARHL) is the most common cause of acquired hearing impairment in dogs. Diagnosis requires objective electrophysiological tests (brainstem evoked response audiometry [BERA]) evaluating the entire audible frequency range in dogs. In our laboratory a method was developed to

Objective correlate of subjective pain perception by contact heat-evoked potentials.

Science.gov (United States)

Granovsky, Yelena; Granot, Michal; Nir, Rony-Reuven; Yarnitsky, David

2008-01-01

The method of pain-evoked potentials has gained considerable acceptance over the last 3 decades regarding its objectivity, repeatability, and quantifiability. The present study explored whether the relationship between pain-evoked potentials and pain psychophysics obtained by contact heat stimuli is similar to those observed for the conventionally used laser stimulation. Evoked potentials (EPs) were recorded in response to contact heat stimuli at different body sites in 24 healthy volunteers. Stimuli at various temperatures were applied to the forearm (43 degrees C, 46 degrees C, 49 degrees C, and 52 degrees C) and leg (46 degrees C and 49 degrees C). The amplitudes of both components (N2 and P2) were strongly associated with the intensity of the applied stimuli and with subjective pain perception. Yet, regression analysis revealed pain perception and not stimulus intensity as the major contributing factor. A significant correlation was found between the forearm and the leg for both psychophysics and EPs amplitude. Contact heat can generate readily distinguishable evoked potentials on the scalp, consistent between upper and lower limbs. Although these potentials bear positive correlation with both stimulus intensity and pain magnitude, the latter is the main contributor to the evoked brain response.

An inventory and update of jealousy-evoking partner behaviours in modern society.

Science.gov (United States)

Dijkstra, Pieternel; Barelds, Dick P H; Groothof, Hinke A K

2010-01-01

The goal of the present study was to identify the most important jealousy-evoking partner behaviours and to examine the extent to which these behaviours evoke jealousy. Based on the literature, a questionnaire was constructed containing 42 jealousy-evoking partner behaviours, including a partner's extra-dyadic involvement with someone else by means of modern communication devices, such as the Internet. A second study examined the extent to which undergraduates and a community sample experienced jealousy in response to these partner behaviours. Results showed that explicit unfaithful behaviours evoked most feelings of jealousy, followed by a partner's emotional or romantic involvement with someone else by means of modern communication devices. In general, older individuals responded with less jealousy in response to a partner's unfaithful and suspicious behaviours. Clinical implications are discussed. (c) 2009 John Wiley & Sons, Ltd.

High frequency oscillations evoked by peripheral magnetic stimulation.

Science.gov (United States)

Biller, S; Simon, L; Fiedler, P; Strohmeier, D; Haueisen, J

2011-01-01

The analysis of somatosensory evoked potentials (SEP) and / or fields (SEF) is a well-established and important tool for investigating the functioning of the peripheral and central human nervous system. A standard technique to evoke SEPs / SEFs is the stimulation of the median nerve by using a bipolar electrical stimulus. We aim at an alternative stimulation technique enabling stimulation of deep nerve structures while reducing patient stress and error susceptibility. In the current study, we apply a commercial transcranial magnetic stimulation system for peripheral magnetic stimulation of the median nerve. We compare the results of simultaneously recorded EEG signals to prove applicability of our technique to evoke SEPs including low frequency components (LFC) as well as high frequency oscillations (HFO). Therefore, we compare amplitude, latency and time-frequency characteristics of the SEP of 14 healthy volunteers after electric and magnetic stimulation. Both low frequency components and high frequency oscillations were detected. The HFOs were superimposed onto the primary cortical response N20. Statistical analysis revealed significantly lower amplitudes and increased latencies for LFC and HFO components after magnetic stimulation. The differences indicate the inability of magnetic stimulation to elicit supramaximal responses. A psycho-perceptual evaluation showed that magnetic stimulation was less unpleasant for 12 out of the 14 volunteers. In conclusion, we showed that LFC and HFO components related to median nerve stimulation can be evoked by peripheral magnetic stimulation.

Nitric oxide and TNFα are critical regulators of reversible lymph node vascular remodeling and adaptive immune response.

Directory of Open Access Journals (Sweden)

Stephanie L Sellers

Full Text Available Lymph node (LN vascular growth, at the level of the main arteriole, was recently characterized for the first time during infection. Arteriole diameter was shown to increase for at least seven days and to occur via a CD4(+ T cell dependent mechanism, with vascular expansion playing a critical role in regulating induction of adaptive immune response. Here, using intravital microscopy of the inguinal LN during herpes simplex type II (HSV-2 infection, the data provides the first studies that demonstrate arteriole expansion during infection is a reversible vascular event that occurs via eutrophic outward remodeling. Furthermore, using genetic ablation models, and pharmacological blockade, we reveal arteriole remodeling and LN hypertrophy to be dependent upon both endothelial nitric oxide synthase (eNOS and TNFα expression. Additionally, we reveal transient changes in nitric oxide (NO levels to be a notable feature of response to viral infection and LN vascular remodeling and provide evidence that mast cells are the critical source of TNFα required to drive arteriole remodeling. Overall, this study is the first to fully characterize LN arteriole vascular changes throughout the course of infection. It effectively reveals a novel role for NO and TNFα in LN cellularity and changes in LN vascularity, which represent key advances in understanding LN vascular physiology and adaptive immune response.

Do ambient urban odors evoke basic emotions?

Directory of Open Access Journals (Sweden)

Sandra Theresia Weber-Glass

2014-04-01

Full Text Available Fragrances, such as plant odors, have been shown to evoke autonomic response patterns associated with Ekman’s (Ekman et al., 1983 basic emotions happiness, surprise, anger, fear, sadness and disgust. Inducing positive emotions by odors in highly frequented public spaces could serve to improve the quality of life in urban environments. Thus, the present study evaluated the potency of ambient odors connoted with an urban environment to evoke basic emotions on an autonomic and cognitive response level. Synthetic mixtures representing the odors of disinfectant, candles / bees wax, summer air, burnt smell, vomit and musty smell as well as odorless water as a control were presented five times in random order to 30 healthy, non-smoking human subjects with intact sense of smell. Skin temperature, skin conductance, breathing rate, forearm muscle activity, blink rate and heart rate were recorded simultaneously. Subjects rated the odors in terms of pleasantness, intensity and familiarity and gave verbal labels to each odor as well as cognitive associations with the basic emotions. The results showed that the amplitude of the skin conductance response varied as a function of odor presentation. Burnt smell and vomit elicited significantly higher electrodermal responses than summer air. Also, a negative correlation was revealed between the amplitude of the skin conductance response and hedonic odor valence indicating that the magnitude of the electrodermal response increased with odor unpleasantness. The analysis of the cognitive associations between odors and basic emotions showed that candles / bees wax and summer air were specifically associated with happiness whereas burnt smell and vomit were uniquely associated with disgust. Our findings suggest that city odors may evoke specific cognitive associations of basic emotions and that autonomic activity elicited by such odors is related to odor hedonics.

Common cortical responses evoked by appearance, disappearance and change of the human face

Directory of Open Access Journals (Sweden)

Kida Tetsuo

2009-04-01

Full Text Available Abstract Background To segregate luminance-related, face-related and non-specific components involved in spatio-temporal dynamics of cortical activations to a face stimulus, we recorded cortical responses to face appearance (Onset, disappearance (Offset, and change (Change using magnetoencephalography. Results Activity in and around the primary visual cortex (V1/V2 showed luminance-dependent behavior. Any of the three events evoked activity in the middle occipital gyrus (MOG at 150 ms and temporo-parietal junction (TPJ at 250 ms after the onset of each event. Onset and Change activated the fusiform gyrus (FG, while Offset did not. This FG activation showed a triphasic waveform, consistent with results of intracranial recordings in humans. Conclusion Analysis employed in this study successfully segregated four different elements involved in the spatio-temporal dynamics of cortical activations in response to a face stimulus. The results show the responses of MOG and TPJ to be associated with non-specific processes, such as the detection of abrupt changes or exogenous attention. Activity in FG corresponds to a face-specific response recorded by intracranial studies, and that in V1/V2 is related to a change in luminance.

Simultaneous recording of electroretinogram and visual evoked response. Focal stimulation under direct observation.

Science.gov (United States)

Hirose, T; Miyake, Y; Hara, A

1977-07-01

A system has been tested that allows simultaneous recording of the retinal response (electroretinogram [ERG]) and the occipital response (visual evoked response [VER]) with focal photic stimulation of the retina under direct observation of the fundus. A helium-neon gas laser is used as a stimulus source. The laser is chopped either by a pen motor or a rotating disc. The laser is attached to a biomicroscope through which the examiner can observe the fundus of the subject during the entire recording session. The optically clear contact lens is made with a flat surface that neutralizes refraction due to the cornea, thereby allowing fundus observation by microscope. Two metal wires mounted inside and outside of the lens serve as the electrode for the ERG. Graticules consisting of concentric circles and radial lines are projected onto the subject's fundus, providing a pattern that the examiner can use to determine the exact location to be stimulated in the fundus. With proper adjustment of stimulus and background illumination, local ERG and VER can be recorded simultaneously by stimulating the macula.

Skin denervation does not alter cortical potentials to surface concentric electrode stimulation: A comparison with laser evoked potentials and contact heat evoked potentials.

Science.gov (United States)

La Cesa, S; Di Stefano, G; Leone, C; Pepe, A; Galosi, E; Alu, F; Fasolino, A; Cruccu, G; Valeriani, M; Truini, A

2018-01-01

In the neurophysiological assessment of patients with neuropathic pain, laser evoked potentials (LEPs), contact heat evoked potentials (CHEPs) and the evoked potentials by the intraepidermal electrical stimulation via concentric needle electrode are widely agreed as nociceptive specific responses; conversely, the nociceptive specificity of evoked potentials by surface concentric electrode (SE-PREPs) is still debated. In this neurophysiological study we aimed at verifying the nociceptive specificity of SE-PREPs. We recorded LEPs, CHEPs and SE-PREPs in eleven healthy participants, before and after epidermal denervation produced by prolonged capsaicin application. We also used skin biopsy to verify the capsaicin-induced nociceptive nerve fibre loss in the epidermis. We found that whereas LEPs and CHEPs were suppressed after capsaicin-induced epidermal denervation, the surface concentric electrode stimulation of the same denervated skin area yielded unchanged SE-PREPs. The suppression of LEPs and CHEPs after nociceptive nerve fibre loss in the epidermis indicates that these techniques are selectively mediated by nociceptive system. Conversely, the lack of SE-PREP changes suggests that SE-PREPs do not provide selective information on nociceptive system function. Capsaicin-induced epidermal denervation abolishes laser evoked potentials (LEPs) and contact heat evoked potentials (CHEPs), but leaves unaffected pain-related evoked potentials by surface concentric electrode (SE-PREPs). These findings suggest that unlike LEPs and CHEPs, SE-PREPs are not selectively mediated by nociceptive system. © 2017 European Pain Federation - EFIC®.

Redundant control of migration and adhesion by ERM proteins in vascular smooth muscle cells

International Nuclear Information System (INIS)

Baeyens, Nicolas; Latrache, Iman; Yerna, Xavier; Noppe, Gauthier; Horman, Sandrine; Morel, Nicole

2013-01-01

Highlights: •The three ERM proteins are expressed in vascular smooth muscle cell. •ERM depletion inhibited PDGF-evoked migration redundantly. •ERM depletion increased cell adhesion redundantly. •ERM depletion did not affect PDGF-evoked Ca signal, Rac1 activation, proliferation. •ERM proteins control PDGF-induced migration by regulating adhesion. -- Abstract: Ezrin, radixin, and moesin possess a very similar structure with a C-terminal actin-binding domain and a N-terminal FERM interacting domain. They are known to be involved in cytoskeleton organization in several cell types but their function in vascular smooth muscle cells (VSMC) is still unknown. The aim of this study was to investigate the role of ERM proteins in cell migration induced by PDGF, a growth factor involved in pathophysiological processes like angiogenesis or atherosclerosis. We used primary cultured VSMC obtained from rat aorta, which express the three ERM proteins. Simultaneous depletion of the three ERM proteins with specific siRNAs abolished the effects of PDGF on cell architecture and migration and markedly increased cell adhesion and focal adhesion size, while these parameters were only slightly affected by depletion of ezrin, radixin or moesin alone. Rac1 activation, cell proliferation, and Ca 2+ signal in response to PDGF were unaffected by ERM depletion. These results indicate that ERM proteins exert a redundant control on PDGF-induced VSMC migration by regulating focal adhesion turn-over and cell adhesion to substrate

Redundant control of migration and adhesion by ERM proteins in vascular smooth muscle cells

Energy Technology Data Exchange (ETDEWEB)

Baeyens, Nicolas; Latrache, Iman; Yerna, Xavier [Laboratory of Cell Physiology, IoNS, Université Catholique de Louvain (Belgium); Noppe, Gauthier; Horman, Sandrine [Pôle de Recherche Cardiovasculaire, IREC, Université Catholique de Louvain (Belgium); Morel, Nicole, E-mail: nicole.morel@uclouvain.be [Laboratory of Cell Physiology, IoNS, Université Catholique de Louvain (Belgium)

2013-11-22

Highlights: •The three ERM proteins are expressed in vascular smooth muscle cell. •ERM depletion inhibited PDGF-evoked migration redundantly. •ERM depletion increased cell adhesion redundantly. •ERM depletion did not affect PDGF-evoked Ca signal, Rac1 activation, proliferation. •ERM proteins control PDGF-induced migration by regulating adhesion. -- Abstract: Ezrin, radixin, and moesin possess a very similar structure with a C-terminal actin-binding domain and a N-terminal FERM interacting domain. They are known to be involved in cytoskeleton organization in several cell types but their function in vascular smooth muscle cells (VSMC) is still unknown. The aim of this study was to investigate the role of ERM proteins in cell migration induced by PDGF, a growth factor involved in pathophysiological processes like angiogenesis or atherosclerosis. We used primary cultured VSMC obtained from rat aorta, which express the three ERM proteins. Simultaneous depletion of the three ERM proteins with specific siRNAs abolished the effects of PDGF on cell architecture and migration and markedly increased cell adhesion and focal adhesion size, while these parameters were only slightly affected by depletion of ezrin, radixin or moesin alone. Rac1 activation, cell proliferation, and Ca{sup 2+} signal in response to PDGF were unaffected by ERM depletion. These results indicate that ERM proteins exert a redundant control on PDGF-induced VSMC migration by regulating focal adhesion turn-over and cell adhesion to substrate.

Evoked Brain Activity and Personnel Performance

Science.gov (United States)

1987-10-01

Shucard and Horn (1972), Galbraith, Gliddon, and Busk (1970), and Callaway (1975), the latter using Navy recruits. Callaway’s own work was reported at...G.C., Gliddon, J.B., & Busk , J. (1970). Visual evoked responses in mentally retarded and nonretarded subjects. American Journal of Mental Deficiency

The pars intermedia: an anatomic basis for a coordinated vascular response to female genital arousal.

Science.gov (United States)

Shih, Cheryl; Cold, Christopher J; Yang, Claire C

2013-06-01

The pars intermedia is an area of the vulva that has been inconsistently described in the literature. We conducted anatomic studies to better describe the tissues and vascular structures of the pars intermedia and proposed a functional rationale of the pars intermedia in the female sexual response. Nine cadaveric vulvectomy specimens were used. Each was serially sectioned and stained with hematoxylin and eosin and Masson's trichrome. Histologic ultrastructural description of the pars intermedia. The pars intermedia contains veins traveling longitudinally in the angle of the clitoris, supported by collagen-rich stromal tissues. These veins drain the different vascular compartments of the vulva, including the clitoris, the bulbs, and labia minora; also, the interconnecting veins link the different vascular compartments. The pars intermedia is not composed of erectile tissue, distinguishing it from the erectile tissues of the corpora cavernosa of the clitoris as well as the corpus spongiosum of the clitoral (vestibular) bulbs. The venous communications of the pars intermedia, linking the erectile tissues with the other vascular compartments of the vulva, appear to provide the anatomic basis for a coordinated vascular response during female sexual arousal. © 2012 International Society for Sexual Medicine.

Phantom somatosensory evoked potentials following selective intraneural electrical stimulation in two amputees.

Science.gov (United States)

Granata, Giuseppe; Di Iorio, Riccardo; Romanello, Roberto; Iodice, Francesco; Raspopovic, Stanisa; Petrini, Francesco; Strauss, Ivo; Valle, Giacomo; Stieglitz, Thomas; Čvančara, Paul; Andreu, David; Divoux, Jean-Louis; Guiraud, David; Wauters, Loic; Hiairrassary, Arthur; Jensen, Winnie; Micera, Silvestro; Rossini, Paolo Maria

2018-06-01

The aim of the paper is to objectively demonstrate that amputees implanted with intraneural interfaces are truly able to feel a sensation in the phantom hand by recording "phantom" somatosensory evoked potentials from the corresponding brain areas. We implanted four transverse intrafascicular multichannel electrodes, available with percutaneous connections to a multichannel electrical stimulator, in the median and ulnar nerves of two left trans-radial amputees. Two channels of the implants that were able to elicit sensations during intraneural nerve stimulation were chosen, in both patients, for recording somatosensory evoked potentials. We recorded reproducible evoked responses by stimulating the median and the ulnar nerves in both cases. Latencies were in accordance with the arrival of somatosensory information to the primary somatosensory cortex. Our results provide evidence that sensations generated by intraneural stimulation are truly perceived by amputees and located in the phantom hand. Moreover, our results strongly suggest that sensations perceived in different parts of the phantom hand result in different evoked responses. Somatosensory evoked potentials obtained by selective intraneural electrical stimulation in amputee patients are a useful tool to provide an objective demonstration of somatosensory feedback in new generation bidirectional prostheses. Copyright © 2018. Published by Elsevier B.V.

Simultaneous EEG/fMRI analysis of the resonance phenomena in steady-state visual evoked responses.

Science.gov (United States)

Bayram, Ali; Bayraktaroglu, Zubeyir; Karahan, Esin; Erdogan, Basri; Bilgic, Basar; Ozker, Muge; Kasikci, Itir; Duru, Adil D; Ademoglu, Ahmet; Oztürk, Cengizhan; Arikan, Kemal; Tarhan, Nevzat; Demiralp, Tamer

2011-04-01

The stability of the steady-state visual evoked potentials (SSVEPs) across trials and subjects makes them a suitable tool for the investigation of the visual system. The reproducible pattern of the frequency characteristics of SSVEPs shows a global amplitude maximum around 10 Hz and additional local maxima around 20 and 40 Hz, which have been argued to represent resonant behavior of damped neuronal oscillators. Simultaneous electroencephalogram/functional magnetic resonance imaging (EEG/fMRI) measurement allows testing of the resonance hypothesis about the frequency-selective increases in SSVEP amplitudes in human subjects, because the total synaptic activity that is represented in the fMRI-Blood Oxygen Level Dependent (fMRI-BOLD) response would not increase but get synchronized at the resonance frequency. For this purpose, 40 healthy volunteers were visually stimulated with flickering light at systematically varying frequencies between 6 and 46 Hz, and the correlations between SSVEP amplitudes and the BOLD responses were computed. The SSVEP frequency characteristics of all subjects showed 3 frequency ranges with an amplitude maximum in each of them, which roughly correspond to alpha, beta and gamma bands of the EEG. The correlation maps between BOLD responses and SSVEP amplitude changes across the different stimulation frequencies within each frequency band showed no significant correlation in the alpha range, while significant correlations were obtained in the primary visual area for the beta and gamma bands. This non-linear relationship between the surface recorded SSVEP amplitudes and the BOLD responses of the visual cortex at stimulation frequencies around the alpha band supports the view that a resonance at the tuning frequency of the thalamo-cortical alpha oscillator in the visual system is responsible for the global amplitude maximum of the SSVEP around 10 Hz. Information gained from the SSVEP/fMRI analyses in the present study might be extrapolated to the

Extracting the basal extracellular dopamine concentrations from the evoked responses: re-analysis of the dopamine kinetics.

Science.gov (United States)

Chen, Kevin C; Budygin, Evgeny A

2007-08-15

Fast-scan cyclic voltammetry in conjunction with carbon fiber microelectrode has been used to study dopamine (DA) release and uptake mechanisms in rat brains because of the smaller size of the electrode and the subsecond resolution. Current voltammetry data were analyzed by a DA kinetic model assuming a zero baseline, which is in conflict with existing microdialysis findings and a recent claim of the striatal extracellular DA concentration at micromolar levels. This work applied a new analysis approach based on a modified DA kinetic model to analyze the kinetics of electrically evoked DA overflow in the caudate-putamen of anesthetized rats. The DA uptake parameters were fitted from the electrical stimulation phase, and subsequently used to calculate theoretical DA uptake rates. Comparison of the theoretical uptake rates with experimental clearance rates allows for the study of the tonic DA release process following electrical stimulations. Analyses of DA voltammetry data suggest that the locally averaged basal level of extracellular DA in the rat striatum might be confined between 95 and 220 nM. The disparate time scales in the clearance kinetics of endogenous and exogenous DA were investigated. Long-distance diffusion could only partially explain the slow clearance time course of exogenous DA. Model simulations and parameter analyses on evoked DA responses indicate that suppression of the nonevoked DA release process immediately following electrical stimulation cannot completely account for the rapid clearance of the electrically evoked DA. Inconsistency in the measured uptake strengths in the literature studying endogenous and exogenous DA remains to be investigated in the future.

Evoked Electromyographically Controlled Electrical Stimulation

Directory of Open Access Journals (Sweden)

Mitsuhiro Hayashibe

2016-07-01

Full Text Available Time-variant muscle responses under electrical stimulation (ES are often problematic for all the applications of neuroprosthetic muscle control. This situation limits the range of ES usage in relevant areas, mainly due to muscle fatigue and also to changes in stimulation electrode contact conditions, especially in transcutaneous ES. Surface electrodes are still the most widely used in noninvasive applications.Electrical field variations caused by changes in the stimulation contact condition markedly affect the resulting total muscle activation levels. Fatigue phenomena under functional electrical stimulation (FES are also well known source of time-varying characteristics coming from muscle response under ES. Therefore it is essential to monitor the actual muscle state and assess the expected muscle response by ES so as to improve the current ES system in favour of adaptive muscle-response-aware FES control. To deal with this issue, we have been studying a novel control technique using evoked electromyography (eEMG signals to compensate for these muscle time-variances under ES for stable neuroprosthetic muscle control. In this perspective article, I overview the background of this topic and highlight important points to be aware of when using ES to induce the desired muscle activation regardless of the time-variance. I also demonstrate how to deal with the common critical problem of ES to move toward robust neuroprosthetic muscle control with the Evoked Electromyographically Controlled Electrical Stimulation paradigm.

Stomatal Blue Light Response Is Present in Early Vascular Plants.

Science.gov (United States)

Doi, Michio; Kitagawa, Yuki; Shimazaki, Ken-ichiro

2015-10-01

Light is a major environmental factor required for stomatal opening. Blue light (BL) induces stomatal opening in higher plants as a signal under the photosynthetic active radiation. The stomatal BL response is not present in the fern species of Polypodiopsida. The acquisition of a stomatal BL response might provide competitive advantages in both the uptake of CO2 and prevention of water loss with the ability to rapidly open and close stomata. We surveyed the stomatal opening in response to strong red light (RL) and weak BL under the RL with gas exchange technique in a diverse selection of plant species from euphyllophytes, including spermatophytes and monilophytes, to lycophytes. We showed the presence of RL-induced stomatal opening in most of these species and found that the BL responses operated in all euphyllophytes except Polypodiopsida. We also confirmed that the stomatal opening in lycophytes, the early vascular plants, is driven by plasma membrane proton-translocating adenosine triphosphatase and K(+) accumulation in guard cells, which is the same mechanism operating in stomata of angiosperms. These results suggest that the early vascular plants respond to both RL and BL and actively regulate stomatal aperture. We also found three plant species that absolutely require BL for both stomatal opening and photosynthetic CO2 fixation, including a gymnosperm, C. revoluta, and the ferns Equisetum hyemale and Psilotum nudum. © 2015 American Society of Plant Biologists. All Rights Reserved.

Gender differences in rival characteristics that evoke jealousy in response to emotional versus sexual infidelity

NARCIS (Netherlands)

Buunk, Abraham (Bram); Dijkstra, Pieternel

2004-01-01

Previous research has shown that in men jealousy is evoked more by a rival's status-related characteristics than in women, whereas in women jealousy is evoked more by a rival's physical attractiveness than in men. The present study examined whether the occurrence of this gender difference depends

Mobilization of endothelial precursor cells: systemic vascular response to musculoskeletal trauma.

LENUS (Irish Health Repository)

Laing, A J

2012-02-03

Postnatal vasculogenesis, the process by which vascular committed bone marrow stem cells or endothelial precursor cells (EPC) migrate, differentiate, and incorporate into the nacent endothelium contributing to physiological and pathological neovascularization, has stimulated much interest. Its contribution to tumor nonvascularization, wound healing, and revascularization associated with skeletal and cardiac muscles ischaemia is established. We evaluated the mobilization of EPCs in response to musculoskeletal trauma. Blood from patients (n = 15) following AO type 42a1 closed diaphyseal tibial fractures was analyzed for CD34 and AC133 cell surface marker expression. Immunomagnetically enriched CD34+ mononuclear cell (MNC(CD34+)) populations were cultured and examined for phenotypic and functional vascular endothelial differentiation. Circulating MNC(CD34+) levels increased sevenfold by day 3 postinjury. Circulating MNC(AC133+) increased 2.5-fold. Enriched MNC(CD34+) populations from day 3 samples in culture exhibited cell cluster formation with sprouting spindles. These cells bound UEA-1 and incorporated fluorescent DiI-Ac-LDL intracellularily. Our findings suggest a systemic provascular response is initiated in response to musculoskeletal trauma. Its therapeutic manipulation may have implications for the potential enhancement of fracture healing.

Influenza A infection attenuates relaxation responses of mouse tracheal smooth muscle evoked by acrolein.

Science.gov (United States)

Cheah, Esther Y; Mann, Tracy S; Burcham, Philip C; Henry, Peter J

2015-02-15

The airway epithelium is an important source of relaxant mediators, and damage to the epithelium caused by respiratory tract viruses may contribute to airway hyperreactivity. The aim of this study was to determine whether influenza A-induced epithelial damage would modulate relaxation responses evoked by acrolein, a toxic and prevalent component of smoke. Male BALB/c mice were inoculated intranasally with influenza A/PR-8/34 (VIRUS-infected) or allantoic fluid (SHAM-infected). On day 4 post-inoculation, isometric tension recording studies were conducted on carbachol pre-contracted tracheal segments isolated from VIRUS and SHAM mice. Relaxant responses to acrolein (30 μM) were markedly smaller in VIRUS segments compared to SHAM segments (2 ± 1% relaxation vs. 28 ± 5%, n=14, pacrolein and SP were reduced in VIRUS segments (>35% reduction, n=6, pacrolein were profoundly diminished in tracheal segments isolated from influenza A-infected mice. The mechanism through which influenza A infection attenuates this response appears to involve reduced production of PGE2 in response to SP due to epithelial cell loss, and may provide insight into the airway hyperreactivity observed with influenza A infection. Copyright © 2014 Elsevier Inc. All rights reserved.

The Relationship of Visual Evoked Potential Asymmetries to the Performance of Sonar Operators

Science.gov (United States)

1981-08-11

also been related to EP variability. Schizophrenic adults and patients with Korsakoff’s Syndrome have shown higher evoked potential variability than...average evoked response in Korsakoff patients. J. Psychiatry Res. 6: 253-260, 1969. Santoro, T. and D. Fender. Rules for the perception of

Conditioning stimulation techniques for enhancement of transcranially elicited evoked motor responses

NARCIS (Netherlands)

Journee, H. -L.; Polak, H. E.; De Kleuver, M.

2007-01-01

Introduction. - In spite of the use of multipulse, transcranial electrical stimulation (TES) is still insufficient in a subgroup of patients to elicit motor-evoked potentials during intraoperative neurophysiological monitoring (IONM). Classic facilitation methods used in awake patients are precluded

Pharmacology of Bradykinin-Evoked Coughing in Guinea Pigs.

Science.gov (United States)

Hewitt, Matthew M; Adams, Gregory; Mazzone, Stuart B; Mori, Nanako; Yu, Li; Canning, Brendan J

2016-06-01

Bradykinin has been implicated as a mediator of the acute pathophysiological and inflammatory consequences of respiratory tract infections and in exacerbations of chronic diseases such as asthma. Bradykinin may also be a trigger for the coughing associated with these and other conditions. We have thus set out to evaluate the pharmacology of bradykinin-evoked coughing in guinea pigs. When inhaled, bradykinin induced paroxysmal coughing that was abolished by the bradykinin B2 receptor antagonist HOE 140. These cough responses rapidly desensitized, consistent with reports of B2 receptor desensitization. Bradykinin-evoked cough was potentiated by inhibition of both neutral endopeptidase and angiotensin-converting enzyme (with thiorphan and captopril, respectively), but was largely unaffected by muscarinic or thromboxane receptor blockade (atropine and ICI 192605), cyclooxygenase, or nitric oxide synthase inhibition (meclofenamic acid and N(G)-nitro-L-arginine). Calcium influx studies in bronchopulmonary vagal afferent neurons dissociated from vagal sensory ganglia indicated that the tachykinin-containing C-fibers arising from the jugular ganglia mediate bradykinin-evoked coughing. Also implicating the jugular C-fibers was the observation that simultaneous blockade of neurokinin2 (NK2; SR48968) and NK3 (SR142801 or SB223412) receptors nearly abolished the bradykinin-evoked cough responses. The data suggest that bradykinin induces coughing in guinea pigs by activating B2 receptors on bronchopulmonary C-fibers. We speculate that therapeutics targeting the actions of bradykinin may prove useful in the treatment of cough. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

Test-retest reliability of speech-evoked auditory brainstem response in healthy children at a low sensation level.

Science.gov (United States)

Zakaria, Mohd Normani; Jalaei, Bahram

2017-11-01

Auditory brainstem responses evoked by complex stimuli such as speech syllables have been studied in normal subjects and subjects with compromised auditory functions. The stability of speech-evoked auditory brainstem response (speech-ABR) when tested over time has been reported but the literature is limited. The present study was carried out to determine the test-retest reliability of speech-ABR in healthy children at a low sensation level. Seventeen healthy children (6 boys, 11 girls) aged from 5 to 9 years (mean = 6.8 ± 3.3 years) were tested in two sessions separated by a 3-month period. The stimulus used was a 40-ms syllable /da/ presented at 30 dB sensation level. As revealed by pair t-test and intra-class correlation (ICC) analyses, peak latencies, peak amplitudes and composite onset measures of speech-ABR were found to be highly replicable. Compared to other parameters, higher ICC values were noted for peak latencies of speech-ABR. The present study was the first to report the test-retest reliability of speech-ABR recorded at low stimulation levels in healthy children. Due to its good stability, it can be used as an objective indicator for assessing the effectiveness of auditory rehabilitation in hearing-impaired children in future studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Postural vascular response in human skin: passive and active reactions to alteration of transmural pressure.

Science.gov (United States)

Jepsen, H; Gaehtgens, P

1993-09-01

Laser-Doppler (LD) fluxmetry was performed in the palmar finger skin of healthy subjects to study the mechanisms contributing to the postural vascular response. Local transmural pressure in the skin blood vessels of the region studied was altered for 1 min in two experimental series either by passive movement of the arm to different vertical hand positions relative to heart level or by application of external pressure (-120-180 mmHg) to the finger. Heart and respiratory rate, arterial blood pressure, and LD flux in the contralateral finger (kept at heart level) were measured. The measurements suggest a compound reaction of local (myogenic) and systemic (neurogenic) mechanisms: the local regulatory component appears as a graded active vascular response elicited by passive vessel distension or compression. A systemic component, associated with a single deep inspiration, is frequently observed during the actual movement of the arm. In addition, prolonged holding of the test hand in a given vertical position also elicits a delayed vascular response in the control hand at heart level, which may be generated by volume receptors in the intrathoracic low-pressure system.

Human sensory-evoked responses differ coincident with either "fusion-memory" or "flash-memory", as shown by stimulus repetition-rate effects

Directory of Open Access Journals (Sweden)

Baird Bill

2006-02-01

Full Text Available Abstract Background: A new method has been used to obtain human sensory evoked-responses whose time-domain waveforms have been undetectable by previous methods. These newly discovered evoked-responses have durations that exceed the time between the stimuli in a continuous stream, thus causing an overlap which, up to now, has prevented their detection. We have named them "A-waves", and added a prefix to show the sensory system from which the responses were obtained (visA-waves, audA-waves, somA-waves. Results: When A-waves were studied as a function of stimulus repetition-rate, it was found that there were systematic differences in waveshape at repetition-rates above and below the psychophysical region in which the sensation of individual stimuli fuse into a continuity. The fusion phenomena is sometimes measured by a "Critical Fusion Frequency", but for this research we can only identify a frequency-region [which we call the STZ (Sensation-Transition Zone]. Thus, the A-waves above the STZ differed from those below the STZ, as did the sensations. Study of the psychophysical differences in auditory and visual stimuli, as shown in this paper, suggest that different stimulus features are detected, and remembered, at stimulation rates above and below STZ. Conclusion: The results motivate us to speculate that: 1 Stimulus repetition-rates above the STZ generate waveforms which underlie "fusion-memory" whereas rates below the STZ show neuronal processing in which "flash-memory" occurs. 2 These two memories differ in both duration and mechanism, though they may occur in the same cell groups. 3 The differences in neuronal processing may be related to "figure" and "ground" differentiation. We conclude that A-waves provide a novel measure of neural processes that can be detected on the human scalp, and speculate that they may extend clinical applications of evoked response recordings. If A-waves also occur in animals, it is likely that A-waves will provide

Human sensory-evoked responses differ coincident with either "fusion-memory" or "flash-memory", as shown by stimulus repetition-rate effects

Science.gov (United States)

Jewett, Don L; Hart, Toryalai; Larson-Prior, Linda J; Baird, Bill; Olson, Marram; Trumpis, Michael; Makayed, Katherine; Bavafa, Payam

2006-01-01

Background: A new method has been used to obtain human sensory evoked-responses whose time-domain waveforms have been undetectable by previous methods. These newly discovered evoked-responses have durations that exceed the time between the stimuli in a continuous stream, thus causing an overlap which, up to now, has prevented their detection. We have named them "A-waves", and added a prefix to show the sensory system from which the responses were obtained (visA-waves, audA-waves, somA-waves). Results: When A-waves were studied as a function of stimulus repetition-rate, it was found that there were systematic differences in waveshape at repetition-rates above and below the psychophysical region in which the sensation of individual stimuli fuse into a continuity. The fusion phenomena is sometimes measured by a "Critical Fusion Frequency", but for this research we can only identify a frequency-region [which we call the STZ (Sensation-Transition Zone)]. Thus, the A-waves above the STZ differed from those below the STZ, as did the sensations. Study of the psychophysical differences in auditory and visual stimuli, as shown in this paper, suggest that different stimulus features are detected, and remembered, at stimulation rates above and below STZ. Conclusion: The results motivate us to speculate that: 1) Stimulus repetition-rates above the STZ generate waveforms which underlie "fusion-memory" whereas rates below the STZ show neuronal processing in which "flash-memory" occurs. 2) These two memories differ in both duration and mechanism, though they may occur in the same cell groups. 3) The differences in neuronal processing may be related to "figure" and "ground" differentiation. We conclude that A-waves provide a novel measure of neural processes that can be detected on the human scalp, and speculate that they may extend clinical applications of evoked response recordings. If A-waves also occur in animals, it is likely that A-waves will provide new methods for

Adverse Weather Evokes Nostalgia.

Science.gov (United States)

van Tilburg, Wijnand A P; Sedikides, Constantine; Wildschut, Tim

2018-03-01

Four studies examined the link between adverse weather and the palliative role of nostalgia. We proposed and tested that (a) adverse weather evokes nostalgia (Hypothesis 1); (b) adverse weather causes distress, which predicts elevated nostalgia (Hypothesis 2); (c) preventing nostalgia exacerbates weather-induced distress (Hypothesis 3); and (d) weather-evoked nostalgia confers psychological benefits (Hypothesis 4). In Study 1, participants listened to recordings of wind, thunder, rain, and neutral sounds. Adverse weather evoked nostalgia. In Study 2, participants kept a 10-day diary recording weather conditions, distress, and nostalgia. We also obtained meteorological data. Adverse weather perceptions were positively correlated with distress, which predicted higher nostalgia. Also, adverse natural weather was associated with corresponding weather perceptions, which predicted elevated nostalgia. (Results were mixed for rain.) In Study 3, preventing nostalgia (via cognitive load) increased weather-evoked distress. In Study 4, weather-evoked nostalgia was positively associated with psychological benefits. The findings pioneer the relevance of nostalgia as source of comfort in adverse weather.

Interhemispheric Asymmetries in Visual Evoked Potential Amplitude

Science.gov (United States)

1980-06-12

Layne, 1965) and of patients with Korsakoff’s syndrome (Malerstein and Callaway, 1969) . In the schizophrenics, the high variability is related to poor...communication. Malerstein, A. J., Callaway, E. Two-tone average evoked response in Korsakoff patients. J. Psychiatr. Res. 6: 253-260, 1969. Marsh, G

Angiogenesis for tumor vascular normalization of Endostar on hepatoma 22 tumor-bearing mice is involved in the immune response.

Science.gov (United States)

Xu, Qingyu; Gu, Junfei; Lv, You; Yuan, Jiarui; Yang, Nan; Chen, Juan; Wang, Chunfei; Hou, Xuefeng; Jia, Xiaobin; Feng, Liang; Yin, Guowen

2018-03-01

Tumor vascular normalization involved in immune response is beneficial to the chemotherapy of tumors. Recombinant human endostatin (Endostar), an angiogenesis inhibitor, has been demonstrated to be effective in hepatocellular cancer (HCC). However, its vascular normalization in HCC and the role of the immune response in angiogenesis were unclear. In the present study, effects of Endostar on tumor vascular normalization were evaluated in hepatoma 22 (H22) tumor-bearing mice. Endostar was able to inhibit the proliferation and infiltration of tumor cells and improve α-fetoprotein, tumor necrosis factor-α and cyclic adenosine 5'-phosphate levels in the serum of H22-bearing mice, as well as the protein expression levels of the immune factors interferon-γ and cluster of differentiation (CD)86 in liver tissue. Endostar also exhibited more marked downregulation of the levels of vascular endothelial growth factor, CD31, matrix metalloproteinase (MMP)-2, MMP-9 and interleukin-17 during day 3-9 treatment, resulting in short-term normalization of tumor blood vessels. The period of vascular normalization was 3-9 days. The results of the present study demonstrated that Endostar was able to induce the period of vascular normalization, contributing to a more efficacious means of HCC treatment combined with other chemotherapy, and this effect was associated with the immune response. It may be concluded that Endostar inhibited immunity-associated angiogenesis behaviors of vascular endothelial cells in response to HCC. The results of the present study provided more reasonable possibility for the combination therapy of Endostar for the treatment of HCC.

Neural Vascular Mechanism for the Cerebral Blood Flow Autoregulation after Hemorrhagic Stroke

Directory of Open Access Journals (Sweden)

Ming Xiao

2017-01-01

Full Text Available During the initial stages of hemorrhagic stroke, including intracerebral hemorrhage and subarachnoid hemorrhage, the reflex mechanisms are activated to protect cerebral perfusion, but secondary dysfunction of cerebral flow autoregulation will eventually reduce global cerebral blood flow and the delivery of metabolic substrates, leading to generalized cerebral ischemia, hypoxia, and ultimately, neuronal cell death. Cerebral blood flow is controlled by various regulatory mechanisms, including prevailing arterial pressure, intracranial pressure, arterial blood gases, neural activity, and metabolic demand. Evoked by the concept of vascular neural network, the unveiled neural vascular mechanism gains more and more attentions. Astrocyte, neuron, pericyte, endothelium, and so forth are formed as a communicate network to regulate with each other as well as the cerebral blood flow. However, the signaling molecules responsible for this communication between these new players and blood vessels are yet to be definitively confirmed. Recent evidence suggested the pivotal role of transcriptional mechanism, including but not limited to miRNA, lncRNA, exosome, and so forth, for the cerebral blood flow autoregulation. In the present review, we sought to summarize the hemodynamic changes and underline neural vascular mechanism for cerebral blood flow autoregulation in stroke-prone state and after hemorrhagic stroke and hopefully provide more systematic and innovative research interests for the pathophysiology and therapeutic strategies of hemorrhagic stroke.

A comparison of auditory evoked potentials to acoustic beats and to binaural beats.

Science.gov (United States)

Pratt, Hillel; Starr, Arnold; Michalewski, Henry J; Dimitrijevic, Andrew; Bleich, Naomi; Mittelman, Nomi

2010-04-01

The purpose of this study was to compare cortical brain responses evoked by amplitude modulated acoustic beats of 3 and 6 Hz in tones of 250 and 1000 Hz with those evoked by their binaural beats counterparts in unmodulated tones to indicate whether the cortical processes involved differ. Event-related potentials (ERPs) were recorded to 3- and 6-Hz acoustic and binaural beats in 2000 ms duration 250 and 1000 Hz tones presented with approximately 1 s intervals. Latency, amplitude and source current density estimates of ERP components to beats-evoked oscillations were determined and compared across beat types, beat frequencies and base (carrier) frequencies. All stimuli evoked tone-onset components followed by oscillations corresponding to the beat frequency, and a subsequent tone-offset complex. Beats-evoked oscillations were higher in amplitude in response to acoustic than to binaural beats, to 250 than to 1000 Hz base frequency and to 3 Hz than to 6 Hz beat frequency. Sources of the beats-evoked oscillations across all stimulus conditions located mostly to left temporal lobe areas. Differences between estimated sources of potentials to acoustic and binaural beats were not significant. The perceptions of binaural beats involve cortical activity that is not different than acoustic beats in distribution and in the effects of beat- and base frequency, indicating similar cortical processing. Copyright 2010 Elsevier B.V. All rights reserved.

Computational Pipeline for NIRS-EEG Joint Imaging of tDCS-Evoked Cerebral Responses-An Application in Ischemic Stroke.

Science.gov (United States)

Guhathakurta, Debarpan; Dutta, Anirban

2016-01-01

Transcranial direct current stimulation (tDCS) modulates cortical neural activity and hemodynamics. Electrophysiological methods (electroencephalography-EEG) measure neural activity while optical methods (near-infrared spectroscopy-NIRS) measure hemodynamics coupled through neurovascular coupling (NVC). Assessment of NVC requires development of NIRS-EEG joint-imaging sensor montages that are sensitive to the tDCS affected brain areas. In this methods paper, we present a software pipeline incorporating freely available software tools that can be used to target vascular territories with tDCS and develop a NIRS-EEG probe for joint imaging of tDCS-evoked responses. We apply this software pipeline to target primarily the outer convexity of the brain territory (superficial divisions) of the middle cerebral artery (MCA). We then present a computational method based on Empirical Mode Decomposition of NIRS and EEG time series into a set of intrinsic mode functions (IMFs), and then perform a cross-correlation analysis on those IMFs from NIRS and EEG signals to model NVC at the lesional and contralesional hemispheres of an ischemic stroke patient. For the contralesional hemisphere, a strong positive correlation between IMFs of regional cerebral hemoglobin oxygen saturation and the log-transformed mean-power time-series of IMFs for EEG with a lag of about -15 s was found after a cumulative 550 s stimulation of anodal tDCS. It is postulated that system identification, for example using a continuous-time autoregressive model, of this coupling relation under tDCS perturbation may provide spatiotemporal discriminatory features for the identification of ischemia. Furthermore, portable NIRS-EEG joint imaging can be incorporated into brain computer interfaces to monitor tDCS-facilitated neurointervention as well as cortical reorganization.

Distinction between added-energy and phase-resetting mechanisms in non-invasively detected somatosensory evoked responses.

Science.gov (United States)

Fedele, T; Scheer, H-J; Burghoff, M; Waterstraat, G; Nikulin, V V; Curio, G

2013-01-01

Non-invasively recorded averaged event-related potentials (ERP) represent a convenient opportunity to investigate human brain perceptive and cognitive processes. Nevertheless, generative ERP mechanisms are still debated. Two previous approaches have been contested in the past: the added-energy model in which the response raises independently from the ongoing background activity, and the phase-reset model, based on stimulus-driven synchronization of oscillatory ongoing activity. Many criteria for the distinction of these two models have been proposed, but there is no definitive methodology to disentangle them, owing also to the limited information at the single trial level. Here, we propose a new approach combining low-noise EEG technology and multivariate decomposition techniques. We present theoretical analyses based on simulated data and identify in high-frequency somatosensory evoked responses an optimal target for the distinction between the two mechanisms.

Music evokes vivid autobiographical memories.

Science.gov (United States)

Belfi, Amy M; Karlan, Brett; Tranel, Daniel

2016-08-01

Music is strongly intertwined with memories-for example, hearing a song from the past can transport you back in time, triggering the sights, sounds, and feelings of a specific event. This association between music and vivid autobiographical memory is intuitively apparent, but the idea that music is intimately tied with memories, seemingly more so than other potent memory cues (e.g., familiar faces), has not been empirically tested. Here, we compared memories evoked by music to those evoked by famous faces, predicting that music-evoked autobiographical memories (MEAMs) would be more vivid. Participants listened to 30 songs, viewed 30 faces, and reported on memories that were evoked. Memories were transcribed and coded for vividness as in Levine, B., Svoboda, E., Hay, J. F., Winocur, G., & Moscovitch, M. [2002. Aging and autobiographical memory: Dissociating episodic from semantic retrieval. Psychology and Aging, 17, 677-689]. In support of our hypothesis, MEAMs were more vivid than autobiographical memories evoked by faces. MEAMs contained a greater proportion of internal details and a greater number of perceptual details, while face-evoked memories contained a greater number of external details. Additionally, we identified sex differences in memory vividness: for both stimulus categories, women retrieved more vivid memories than men. The results show that music not only effectively evokes autobiographical memories, but that these memories are more vivid than those evoked by famous faces.

Single-sweep spectral analysis of contact heat evoked potentials

DEFF Research Database (Denmark)

Hansen, Tine M; Graversen, Carina; Frøkjaer, Jens B

2015-01-01

AIMS: The cortical response to nociceptive thermal stimuli recorded as contact heat evoked potentials (CHEPs) may be altered by morphine. However, previous studies have averaged CHEPs over multiple stimuli, which are confounded by jitter between sweeps. Thus, the aim was to assess single-sweep ch......AIMS: The cortical response to nociceptive thermal stimuli recorded as contact heat evoked potentials (CHEPs) may be altered by morphine. However, previous studies have averaged CHEPs over multiple stimuli, which are confounded by jitter between sweeps. Thus, the aim was to assess single...... by 13% (P = 0.04) and 9% (P = 0.007), while the beta and gamma bands were increased by 10% (P = 0.006) and 24% (P = 0.04). CONCLUSION: The decreases in the delta and theta band are suggested to represent a decrease in the pain specific morphology of the CHEPs, which indicates a diminished pain response...

Independent component analysis for cochlear implant artifacts attenuation from electrically evoked auditory steady-state response measurements

Science.gov (United States)

Deprez, Hanne; Gransier, Robin; Hofmann, Michael; van Wieringen, Astrid; Wouters, Jan; Moonen, Marc

2018-02-01

Objective. Electrically evoked auditory steady-state responses (EASSRs) are potentially useful for objective cochlear implant (CI) fitting and follow-up of the auditory maturation in infants and children with a CI. EASSRs are recorded in the electro-encephalogram (EEG) in response to electrical stimulation with continuous pulse trains, and are distorted by significant CI artifacts related to this electrical stimulation. The aim of this study is to evaluate a CI artifacts attenuation method based on independent component analysis (ICA) for three EASSR datasets. Approach. ICA has often been used to remove CI artifacts from the EEG to record transient auditory responses, such as cortical evoked auditory potentials. Independent components (ICs) corresponding to CI artifacts are then often manually identified. In this study, an ICA based CI artifacts attenuation method was developed and evaluated for EASSR measurements with varying CI artifacts and EASSR characteristics. Artifactual ICs were automatically identified based on their spectrum. Main results. For 40 Hz amplitude modulation (AM) stimulation at comfort level, in high SNR recordings, ICA succeeded in removing CI artifacts from all recording channels, without distorting the EASSR. For lower SNR recordings, with 40 Hz AM stimulation at lower levels, or 90 Hz AM stimulation, ICA either distorted the EASSR or could not remove all CI artifacts in most subjects, except for two of the seven subjects tested with low level 40 Hz AM stimulation. Noise levels were reduced after ICA was applied, and up to 29 ICs were rejected, suggesting poor ICA separation quality. Significance. We hypothesize that ICA is capable of separating CI artifacts and EASSR in case the contralateral hemisphere is EASSR dominated. For small EASSRs or large CI artifact amplitudes, ICA separation quality is insufficient to ensure complete CI artifacts attenuation without EASSR distortion.

Normative findings of electrically evoked compound action potential measurements using the neural response telemetry of the Nucleus CI24M cochlear implant system.

NARCIS (Netherlands)

Cafarelli-Dees, D.; Dillier, N.; Lai, W.K.; Wallenberg, E. von; Dijk, B. van; Akdas, F.; Aksit, M.; Batman, C.; Beynon, A.J.; Burdo, S.; Chanal, J.M.; Collet, L.; Conway, M.; Coudert, C.; Craddock, L.; Cullington, H.; Deggouj, N.; Fraysse, B.; Grabel, S.; Kiefer, J.; Kiss, J.G.; Lenarz, T.; Mair, A.; Maune, S.; Muller-Deile, J.; Piron, J.P.; Razza, S.; Tasche, C.; Thai-Van, H.; Toth, F.; Truy, E.; Uziel, A.; Smoorenburg, G.F.

2005-01-01

One hundred and forty-seven adult recipients of the Nucleus 24 cochlear implant system, from 13 different European countries, were tested using neural response telemetry to measure the electrically evoked compound action potential (ECAP), according to a standardised postoperative measurement

A novel method for extraction of neural response from single channel cochlear implant auditory evoked potentials.

Science.gov (United States)

Sinkiewicz, Daniel; Friesen, Lendra; Ghoraani, Behnaz

2017-02-01

Cortical auditory evoked potentials (CAEP) are used to evaluate cochlear implant (CI) patient auditory pathways, but the CI device produces an electrical artifact, which obscures the relevant information in the neural response. Currently there are multiple methods, which attempt to recover the neural response from the contaminated CAEP, but there is no gold standard, which can quantitatively confirm the effectiveness of these methods. To address this crucial shortcoming, we develop a wavelet-based method to quantify the amount of artifact energy in the neural response. In addition, a novel technique for extracting the neural response from single channel CAEPs is proposed. The new method uses matching pursuit (MP) based feature extraction to represent the contaminated CAEP in a feature space, and support vector machines (SVM) to classify the components as normal hearing (NH) or artifact. The NH components are combined to recover the neural response without artifact energy, as verified using the evaluation tool. Although it needs some further evaluation, this approach is a promising method of electrical artifact removal from CAEPs. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Quantitative Evaluation of Tumor Early Response to a Vascular-Disrupting Agent with Dynamic PET.

Science.gov (United States)

Guo, Ning; Zhang, Fan; Zhang, Xiaomeng; Guo, Jinxia; Lang, Lixin; Kiesewetter, Dale O; Niu, Gang; Li, Quanzheng; Chen, Xiaoyuan

2015-12-01

The purpose of this study is to evaluate the early response of tumors to a vascular-disrupting agent (VDA) VEGF121/recombinant toxin gelonin (rGel) using dynamic [(18)F]FPPRGD2 positron emission tomography (PET) and kinetic parameter estimation. Two tumor xenograft models: U87MG (highly vascularized) and A549 (moderately vascularized), were selected, and both were randomized into treatment and control groups. Sixty-minute dynamic PET scans with [(18)F]FPPRGD2 that targets to integrin αvβ3 were performed at days 0 (baseline), 1, and 3 since VEGF121/rGel treatment started. Dynamic PET-derived binding potential (BPND) and parametric maps were compared with tumor uptake (%ID/g) and the static PET image at 1 h after the tracer administration. The growth of U87MG tumor was obviously delayed upon VEGF121/rGel treatment. A549 tumor was not responsive to the same treatment. BPND of treated U87MG tumors decreased significantly at day 1 (p dynamic PET with [(18)F]FPPRGD2 shows advantages in distinguishing effective from ineffective treatment during the course of VEGF121/rGel therapy at early stage and is therefore more sensitive in assessing therapy response than static PET.

Dose-response characteristics of methylphenidate on locomotor behavior and on sensory evoked potentials recorded from the VTA, NAc, and PFC in freely behaving rats

Directory of Open Access Journals (Sweden)

Swann Alan C

2006-01-01

Full Text Available Abstract Background Methylphenidate (MPD is a psychostimulant commonly prescribed for attention deficit/hyperactivity disorder. The mode of action of the brain circuitry responsible for initiating the animals' behavior in response to psychostimulants is not well understood. There is some evidence that psychostimulants activate the ventral tegmental area (VTA, nucleus accumbens (NAc, and prefrontal cortex (PFC. Methods The present study was designed to investigate the acute dose-response of MPD (0.6, 2.5, and 10.0 mg/kg on locomotor behavior and sensory evoked potentials recorded from the VTA, NAc, and PFC in freely behaving rats previously implanted with permanent electrodes. For locomotor behavior, adult male Wistar-Kyoto (WKY; n = 39 rats were given saline on experimental day 1 and either saline or an acute injection of MPD (0.6, 2.5, or 10.0 mg/kg, i.p. on experimental day 2. Locomotor activity was recorded for 2-h post injection on both days using an automated, computerized activity monitoring system. Electrophysiological recordings were also performed in the adult male WKY rats (n = 10. Five to seven days after the rats had recovered from the implantation of electrodes, each rat was placed in a sound-insulated, electrophysiological test chamber where its sensory evoked field potentials were recorded before and after saline and 0.6, 2.5, and 10.0 mg/kg MPD injection. Time interval between injections was 90 min. Results Results showed an increase in locomotion with dose-response characteristics, while a dose-response decrease in amplitude of the components of sensory evoked field responses of the VTA, NAc, and PFC neurons. For example, the P3 component of the sensory evoked field response of the VTA decreased by 19.8% ± 7.4% from baseline after treatment of 0.6 mg/kg MPD, 37.8% ± 5.9% after 2.5 mg/kg MPD, and 56.5% ± 3.9% after 10 mg/kg MPD. Greater attenuation from baseline was observed in the NAc and PFC. Differences in the intensity of

Odor-evoked inhibition of olfactory sensory neurons drives olfactory perception in Drosophila.

Science.gov (United States)

Cao, Li-Hui; Yang, Dong; Wu, Wei; Zeng, Xiankun; Jing, Bi-Yang; Li, Meng-Tong; Qin, Shanshan; Tang, Chao; Tu, Yuhai; Luo, Dong-Gen

2017-11-07

Inhibitory response occurs throughout the nervous system, including the peripheral olfactory system. While odor-evoked excitation in peripheral olfactory cells is known to encode odor information, the molecular mechanism and functional roles of odor-evoked inhibition remain largely unknown. Here, we examined Drosophila olfactory sensory neurons and found that inhibitory odors triggered outward receptor currents by reducing the constitutive activities of odorant receptors, inhibiting the basal spike firing in olfactory sensory neurons. Remarkably, this odor-evoked inhibition of olfactory sensory neurons elicited by itself a full range of olfactory behaviors from attraction to avoidance, as did odor-evoked olfactory sensory neuron excitation. These results indicated that peripheral inhibition is comparable to excitation in encoding sensory signals rather than merely regulating excitation. Furthermore, we demonstrated that a bidirectional code with both odor-evoked inhibition and excitation in single olfactory sensory neurons increases the odor-coding capacity, providing a means of efficient sensory encoding.

Awareness during anaesthesia for surgery requiring evoked potential monitoring: A pilot study

Directory of Open Access Journals (Sweden)

Pritish J Korula

2017-01-01

Full Text Available Background: Evoked potential monitoring such as somatosensory-evoked potential (SSEP or motor-evoked potential (MEP monitoring during surgical procedures in proximity to the spinal cord requires minimising the minimum alveolar concentrations (MACs below the anaesthetic concentrations normally required (1 MAC to prevent interference in amplitude and latency of evoked potentials. This could result in awareness. Our primary objective was to determine the incidence of awareness while administering low MAC inhalational anaesthetics for these unique procedures. The secondary objective was to assess the adequacy of our anaesthetic technique from neurophysiologist′s perspective. Methods: In this prospective observational pilot study, 61 American Society of Anesthesiologists 1 and 2 patients undergoing spinal surgery for whom intraoperative evoked potential monitoring was performed were included; during the maintenance phase, 0.7-0.8 MAC of isoflurane was targeted. We evaluated the intraoperative depth of anaesthesia using a bispectral (BIS index monitor as well as the patients response to surgical stimulus (PRST scoring system. Post-operatively, a modified Bruce questionnaire was used to verify awareness. The adequacy of evoked potential readings was also assessed. Results: Of the 61 patients, no patient had explicit awareness. Intraoperatively, 19 of 61 patients had a BIS value of above sixty at least once, during surgery. There was no correlation with PRST scoring and BIS during surgery. Fifty-four out of 61 patient′s evoked potential readings were deemed ′good′ or ′fair′ for the conduct of electrophysiological monitoring. Conclusions: This pilot study demonstrates that administering low MAC inhalational anaesthetics to facilitate evoked potential monitoring does not result in explicit awareness. However, larger studies are needed to verify this. The conduct of SSEP electrophysiological monitoring was satisfactory with the use of this

The Paradox of Music-Evoked Sadness: An Online Survey

Science.gov (United States)

Taruffi, Liila; Koelsch, Stefan

2014-01-01

This study explores listeners’ experience of music-evoked sadness. Sadness is typically assumed to be undesirable and is therefore usually avoided in everyday life. Yet the question remains: Why do people seek and appreciate sadness in music? We present findings from an online survey with both Western and Eastern participants (N = 772). The survey investigates the rewarding aspects of music-evoked sadness, as well as the relative contribution of listener characteristics and situational factors to the appreciation of sad music. The survey also examines the different principles through which sadness is evoked by music, and their interaction with personality traits. Results show 4 different rewards of music-evoked sadness: reward of imagination, emotion regulation, empathy, and no “real-life” implications. Moreover, appreciation of sad music follows a mood-congruent fashion and is greater among individuals with high empathy and low emotional stability. Surprisingly, nostalgia rather than sadness is the most frequent emotion evoked by sad music. Correspondingly, memory was rated as the most important principle through which sadness is evoked. Finally, the trait empathy contributes to the evocation of sadness via contagion, appraisal, and by engaging social functions. The present findings indicate that emotional responses to sad music are multifaceted, are modulated by empathy, and are linked with a multidimensional experience of pleasure. These results were corroborated by a follow-up survey on happy music, which indicated differences between the emotional experiences resulting from listening to sad versus happy music. This is the first comprehensive survey of music-evoked sadness, revealing that listening to sad music can lead to beneficial emotional effects such as regulation of negative emotion and mood as well as consolation. Such beneficial emotional effects constitute the prime motivations for engaging with sad music in everyday life. PMID:25330315

The paradox of music-evoked sadness: an online survey.

Directory of Open Access Journals (Sweden)

Liila Taruffi

Full Text Available This study explores listeners' experience of music-evoked sadness. Sadness is typically assumed to be undesirable and is therefore usually avoided in everyday life. Yet the question remains: Why do people seek and appreciate sadness in music? We present findings from an online survey with both Western and Eastern participants (N = 772. The survey investigates the rewarding aspects of music-evoked sadness, as well as the relative contribution of listener characteristics and situational factors to the appreciation of sad music. The survey also examines the different principles through which sadness is evoked by music, and their interaction with personality traits. Results show 4 different rewards of music-evoked sadness: reward of imagination, emotion regulation, empathy, and no "real-life" implications. Moreover, appreciation of sad music follows a mood-congruent fashion and is greater among individuals with high empathy and low emotional stability. Surprisingly, nostalgia rather than sadness is the most frequent emotion evoked by sad music. Correspondingly, memory was rated as the most important principle through which sadness is evoked. Finally, the trait empathy contributes to the evocation of sadness via contagion, appraisal, and by engaging social functions. The present findings indicate that emotional responses to sad music are multifaceted, are modulated by empathy, and are linked with a multidimensional experience of pleasure. These results were corroborated by a follow-up survey on happy music, which indicated differences between the emotional experiences resulting from listening to sad versus happy music. This is the first comprehensive survey of music-evoked sadness, revealing that listening to sad music can lead to beneficial emotional effects such as regulation of negative emotion and mood as well as consolation. Such beneficial emotional effects constitute the prime motivations for engaging with sad music in everyday life.

The paradox of music-evoked sadness: an online survey.

Science.gov (United States)

Taruffi, Liila; Koelsch, Stefan

2014-01-01

This study explores listeners' experience of music-evoked sadness. Sadness is typically assumed to be undesirable and is therefore usually avoided in everyday life. Yet the question remains: Why do people seek and appreciate sadness in music? We present findings from an online survey with both Western and Eastern participants (N = 772). The survey investigates the rewarding aspects of music-evoked sadness, as well as the relative contribution of listener characteristics and situational factors to the appreciation of sad music. The survey also examines the different principles through which sadness is evoked by music, and their interaction with personality traits. Results show 4 different rewards of music-evoked sadness: reward of imagination, emotion regulation, empathy, and no "real-life" implications. Moreover, appreciation of sad music follows a mood-congruent fashion and is greater among individuals with high empathy and low emotional stability. Surprisingly, nostalgia rather than sadness is the most frequent emotion evoked by sad music. Correspondingly, memory was rated as the most important principle through which sadness is evoked. Finally, the trait empathy contributes to the evocation of sadness via contagion, appraisal, and by engaging social functions. The present findings indicate that emotional responses to sad music are multifaceted, are modulated by empathy, and are linked with a multidimensional experience of pleasure. These results were corroborated by a follow-up survey on happy music, which indicated differences between the emotional experiences resulting from listening to sad versus happy music. This is the first comprehensive survey of music-evoked sadness, revealing that listening to sad music can lead to beneficial emotional effects such as regulation of negative emotion and mood as well as consolation. Such beneficial emotional effects constitute the prime motivations for engaging with sad music in everyday life.

The Role of Odor-Evoked Memory in Psychological and Physiological Health.

Science.gov (United States)

Herz, Rachel S

2016-07-19

This article discusses the special features of odor-evoked memory and the current state-of-the-art in odor-evoked memory research to show how these unique experiences may be able to influence and benefit psychological and physiological health. A review of the literature leads to the conclusion that odors that evoke positive autobiographical memories have the potential to increase positive emotions, decrease negative mood states, disrupt cravings, and reduce physiological indices of stress, including systemic markers of inflammation. Olfactory perception factors and individual difference characteristics that would need to be considered in therapeutic applications of odor-evoked-memory are also discussed. This article illustrates how through the experimentally validated mechanisms of odor-associative learning and the privileged neuroanatomical relationship that exists between olfaction and the neural substrates of emotion, odors can be harnessed to induce emotional and physiological responses that can improve human health and wellbeing.

The Role of Odor-Evoked Memory in Psychological and Physiological Health

Directory of Open Access Journals (Sweden)

Rachel S. Herz

2016-07-01

Full Text Available This article discusses the special features of odor-evoked memory and the current state-of-the-art in odor-evoked memory research to show how these unique experiences may be able to influence and benefit psychological and physiological health. A review of the literature leads to the conclusion that odors that evoke positive autobiographical memories have the potential to increase positive emotions, decrease negative mood states, disrupt cravings, and reduce physiological indices of stress, including systemic markers of inflammation. Olfactory perception factors and individual difference characteristics that would need to be considered in therapeutic applications of odor-evoked-memory are also discussed. This article illustrates how through the experimentally validated mechanisms of odor-associative learning and the privileged neuroanatomical relationship that exists between olfaction and the neural substrates of emotion, odors can be harnessed to induce emotional and physiological responses that can improve human health and wellbeing.

Proprioceptive evoked gamma oscillations

DEFF Research Database (Denmark)

Arnfred, S.M.; Hansen, Lars Kai; Parnas, J.

2007-01-01

A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able...... to evoke gamma oscillations. EEG was recorded using 64 channels in 14 healthy subjects. In each of three runs a stimulus of 100 g load increment in each hand was presented in 120 trials. Data were wavelet transformed and runs collapsed. Inter-trial phase coherence (ITPC) was computed as the best measure...

Do video games evoke specific types of epileptic seizures?

Science.gov (United States)

Piccioli, Marta; Vigevano, Federico; Buttinelli, Carla; Kasteleijn-Nolst Trenité, Dorothée G A

2005-11-01

We determined whether epileptic clinical manifestations evoked by playing video games (VG) differ from those evoked by intermittent photic stimulation (IPS) or striped patterns (P). We exposed nine children who had TV- and VG-evoked seizures in daily life to 12 VG after standardized photic stimulation and pattern stimulation. Their EEGs were recorded continuously, analyzed, and then correlated with a video of their behavior. Similar types of clinical signs were seen during VG, P, and IPS, but the signs we observed were more subtle during the VG. Eight patients showed a clear lateralization. A new observation was the lowering of the eyelids to a state of half-closed. Our study suggests that the type of visual stimulus provoking a photoparoxysmal response or seizure is not particularly relevant. The children belonged to different epilepsy groups, and our findings add to the discussion on the boundaries of the epilepsy types.

Muscle synergies evoked by microstimulation are preferentially encoded during behavior

Directory of Open Access Journals (Sweden)

Simon Alexander Overduin

2014-03-01

Full Text Available Electrical microstimulation studies provide some of the most direct evidence for the neural representation of muscle synergies. These synergies, i.e. coordinated activations of groups of muscles, have been proposed as building blocks for the construction of motor behaviors by the nervous system. Intraspinal or intracortical microstimulation has been shown to evoke muscle patterns that can be resolved into a small set of synergies similar to those seen in natural behavior. However, questions remain about the validity of microstimulation as a probe of neural function, particularly given the relatively long trains of supratheshold stimuli used in these studies. Here, we examined whether muscle synergies evoked during intracortical microstimulation in two rhesus macaques were similarly encoded by nearby motor cortical units during a purely voluntary behavior involving object reach, grasp, and carry movements. At each microstimulation site we identified the synergy most strongly evoked among those extracted from muscle patterns evoked over all microstimulation sites. For each cortical unit recorded at the same microstimulation site, we then identified the synergy most strongly encoded among those extracted from muscle patterns recorded during the voluntary behavior. We found that the synergy most strongly evoked at an intracortical microstimulation site matched the synergy most strongly encoded by proximal units more often than expected by chance. These results suggest a common neural substrate for microstimulation-evoked motor responses and for the generation of muscle patterns during natural behaviors.

Baroreflexes of the rat. IV. ADN-evoked responses at the NTS.

Science.gov (United States)

Tang, Xiaorui; Dworkin, Barry R

2007-12-01

In a long-term (7-21 days) neuromuscular blocked (NMB) rat preparation, using precise single-pulse aortic depressor nerve (ADN) stimulation and stable chronic evoked response (ER) recordings from the dorsal-medial solitary nucleus (dmNTS), two different response patterns were observed: continuous and discrete. For the continuous pattern, activity began approximately 3 ms after the stimulus and persisted for 45 ms; for the discrete pattern, two complexes were separated by a gap from approximately 17 to 25 ms. The early complex was probably transmitted via A-fibers: it had a low stimulus current threshold and an average conduction velocity (CV) of 0.58-5.5 m/s; the high threshold late (HTL) complex had a CV = 0.26-0.58 m/s. The average stimulus amplitude-ER magnitude transduction curves for the A and HTL complexes were sigmoidal. For individual rats, in the linear range, mean r2 = 0.96 +/- 0.03 for both complexes. The average stimulus amplitude vs. the systolic blood pressure change (delta sBP) transduction curve was also approximately linear; however, for individual rats, the relationship was not consistently reliable: mean r2 = 0.48 +/- 0.19. Approximately 90% of recording sites had respiratory, and 50% had cardiac synchronism. The NMB preparation is useful for studying central baroreflex mechanisms that operate on time scales of days or weeks, such as adaptation and other kinds of neural plasticity.

Non-invasive vascular imaging: assessing tumour vascularity

International Nuclear Information System (INIS)

Delorme, S.; Knopp, M.V.

1998-01-01

Non-invasive assessment of vascularity is a new diagnostic approach to characterise tumours. Vascular assessment is based on the pathophysiology of tumour angiogenesis and its diagnostic implications for tumour biology, prognosis and therapy response. Two current techniques investigating vascular features in addition to morphology are Doppler ultrasonography and contrast-enhanced MRI. Diagnostic differentiation has been shown to be possible with Doppler, and a high degree of observed vascularity could be linked to an aggressive course of the disease. Dynamic MRI using gadolinium chelates is already used clinically to detect and differentiate tumours. The histological correlation shows that capillary permeability is increased in malignant tumours and is the best criterion for differentiation from benign processes. Permeability and perfusion factors seem to be more diagnostic than overall vessel density. New clinical applications are currently being established for therapy monitoring. Further instrumental developments will bring harmonic imaging in Doppler, and faster imaging techniques, higher spatial resolution and novel pharmacokinetic concepts in MRI. Upcoming contrast agents for both Doppler and MRI will further improve estimation of intratumoural blood volume and vascular permeability. (orig.)

Effects of single cycle binaural beat duration on auditory evoked potentials.

Science.gov (United States)

Mihajloski, Todor; Bohorquez, Jorge; Özdamar, Özcan

2014-01-01

Binaural beat (BB) illusions are experienced as continuous central pulsations when two sounds with slightly different frequencies are delivered to each ear. It has been shown that steady-state auditory evoked potentials (AEPs) to BBs can be captured and investigated. The authors recently developed a new method of evoking transient AEPs to binaural beats using frequency modulated stimuli. This methodology was able to create single BBs in predetermined intervals with varying carrier frequencies. This study examines the effects of the BB duration and the frequency modulating component of the stimulus on the binaural beats and their evoked potentials. Normal hearing subjects were tested with a set of four durations (25, 50, 100, and 200 ms) with two stimulation configurations, binaural dichotic (binaural beats) and diotic (frequency modulation). The results obtained from the study showed that out of the given durations, the 100 ms beat, was capable of evoking the largest amplitude responses. The frequency modulation effect showed a decrease in peak amplitudes with increasing beat duration until their complete disappearance at 200 ms. Even though, at 200 ms, the frequency modulation effects were not present, the binaural beats were still perceived and captured as evoked potentials.

Near-infrared spectroscopy can detect differences in vascular responsiveness to a hyperglycaemic challenge in individuals with obesity compared to normal-weight individuals.

Science.gov (United States)

Soares, Rogério Nogueira; Reimer, Raylene A; Alenezi, Zaid; Doyle-Baker, Patricia K; Murias, Juan Manuel

2018-01-01

To examine whether the near-infrared spectroscopy combined with vascular occlusion test technique could detect differences in vascular responsiveness during hyperglycaemia between normal-weight individuals and individuals with obesity. A total of 16 normal-weight individuals (body mass index, 21.3 ± 1.7 kg/m 2 ) and 13 individuals with obesity (body mass index, 34.4 ± 2.0 kg/m 2 ) were submitted to five vascular occlusion tests (Pre, 30, 60, 90 and 120 min after glucose challenge). Vascular responsiveness was determined by the Slope 2 (Slope 2 StO 2 ) and the area under the curve (StO 2AUC ) of oxygen saturation derived from near-infrared spectroscopy-vascular occlusion test. The Slope 2 StO 2 increased from 1.07 ± 0.16%/s (Pre) to 1.53 ± 0.21%/s at 90 min ( p obese it increased from 0.71 ± 0.09%/s (Pre) to 0.92 ± 0.14%/s at 60 min ( p obesity. Near-infrared spectroscopy-vascular occlusion test technique was capable of detecting differences in vascular responsiveness during hyperglycaemia between normal-weight individuals and individuals with obesity.

Speech-evoked brainstem frequency-following responses during verbal transformations due to word repetition.

Science.gov (United States)

Galbraith, G C; Jhaveri, S P; Kuo, J

1997-01-01

Speech-evoked brainstem frequency-following responses (FFRs) were recorded to repeated presentations of the same stimulus word. Word repetition results in illusory verbal transformations (VTs) in which word perceptions can differ markedly from the actual stimulus. Previous behavioral studies support an explanation of VTs based on changes in arousal or attention. Horizontal and vertical dipole FFRs were recorded to assess responses with putative origins in the auditory nerve and central brainstem, respectively. FFRs were recorded from 18 subjects when they correctly heard the stimulus and when they reported VTs. Although horizontal and vertical dipole FFRs showed different frequency response patterns, dipoles did not differentiate between perceptual conditions. However, when subjects were divided into low- and high-VT groups (based on percentage of VT trials), a significant Condition x Group interaction resulted. This interaction showed the largest difference in FFR amplitudes during VT trials, with the low-VT group showing increased amplitudes, and the high-VT group showing decreased amplitudes, relative to trials in which the stimulus was correctly perceived. These results demonstrate measurable subject differences in the early processing of complex signals, due to possible effects of attention on the brainstem FFR. The present research shows that the FFR is useful in understanding human language as it is coded and processed in the brainstem auditory pathway.

Exposure to Experimental Preeclampsia in Mice Enhances the Vascular Response to Future Injury

Science.gov (United States)

Pruthi, Dafina; Khankin, Eliyahu V.; Blanton, Robert M.; Aronovitz, Mark; Burke, Suzanne D.; McCurley, Amy; Karumanchi, S. Ananth; Jaffe, Iris Z.

2015-01-01

Cardiovascular disease (CVD) remains the leading killer of women in developed nations. One gender-specific risk factor is preeclampsia (PE), a syndrome of hypertension and proteinuria that complicates 5% of pregnancies. Although PE resolves after delivery, exposed women are at increased long term risk of premature CVD and mortality. Preexisting CVD risk factors are associated with increased risk of developing PE but whether PE merely uncovers risk or contributes directly to future CVD remains a critical unanswered question. A mouse PE model was used to test the hypothesis that PE causes an enhanced vascular response to future vessel injury. A PE-like state was induced in pregnant CD1 mice by overexpressing soluble fms-like tyrosine kinase-1 (sFlt-1), a circulating anti-angiogenic protein that induces hypertension and glomerular disease resembling human PE. Two months post-partum, sFlt-1 levels and blood pressure normalized and cardiac size and function by echocardiography and renal histology were indistinguishable in PE-exposed compared to control mice. Mice were then challenged with unilateral carotid injury. PE-exposed mice had significantly enhanced vascular remodeling with increased vascular smooth muscle cell proliferation (180% increase, P<0.01) and vessel fibrosis (216% increase, P<0.001) compared to control pregnancy. In the contralateral uninjured vessel, there was no difference in remodeling after exposure to PE. These data support a new model in which vessels exposed to PE retain a persistently enhanced vascular response to injury despite resolution of PE after delivery. This new paradigm may contribute to the substantially increased risk of CVD in woman exposed to PE. PMID:25712723

The effects of chronic resveratrol treatment on vascular responsiveness of streptozotocin-induced diabetic rats.

Science.gov (United States)

Silan, Coskun

2008-05-01

Deficiency in the vasorelaxant capacity is a result of an oxidative stress in diabetic animals and seems to be an etiological factor of vascular complications of diabetes. The present study was designed to examine whether resveratrol (RSV), a polyphenolic compound which is naturally present in grape and red wine, has a protective effect on diabetic aorta. Resveratrol (5 mg/kg/d, i.p.) was administered for 42 d to streptozotocin (STZ) (60 mg/kg) induced diabetic rats. Loss of weight, hyperglycemia, and elevated levels of plasma malondialdehyde (MDA) were observed in diabetic rats. Resveratrol treatment was significantly effective for these metabolic and biochemical abnormalities. The contractile responses of the aorta were recorded. Compared with control subjects, the aorta showed significantly enhanced contractile responses to noradrenaline (NA), but not to potassium chloride (KCl), in diabetic rats. Treatment of diabetic rats with resveratrol significantly reversed the increases in responsiveness and sensitivity of aorta to noradrenaline. In diabetic aorta, the relaxation response to acetylcholine (Ach) was found to be significantly decreased compared with control subjects, and resveratrol treatment reversed this; no such change was observed in the relaxation response to sodium nitroprusside (SNP). These results indicated that resveratrol significantly improved not only glucose metabolism and oxidative injury but also impaired vascular responses in streptozotocin induced diabetic rats.

HCN channels segregate stimulation‐evoked movement responses in neocortex and allow for coordinated forelimb movements in rodents

Science.gov (United States)

Farrell, Jordan S.; Palmer, Laura A.; Singleton, Anna C.; Pittman, Quentin J.; Teskey, G. Campbell

2016-01-01

Key points The present study tested whether HCN channels contribute to the organization of motor cortex and to skilled motor behaviour during a forelimb reaching task.Experimental reductions in HCN channel signalling increase the representation of complex multiple forelimb movements in motor cortex as assessed by intracortical microstimulation.Global HCN1KO mice exhibit reduced reaching accuracy and atypical movements during a single‐pellet reaching task relative to wild‐type controls.Acute pharmacological inhibition of HCN channels in forelimb motor cortex decreases reaching accuracy and increases atypical movements during forelimb reaching. Abstract The mechanisms by which distinct movements of a forelimb are generated from the same area of motor cortex have remained elusive. Here we examined a role for HCN channels, given their ability to alter synaptic integration, in the expression of forelimb movement responses during intracortical microstimulation (ICMS) and movements of the forelimb on a skilled reaching task. We used short‐duration high‐resolution ICMS to evoke forelimb movements following pharmacological (ZD7288), experimental (electrically induced cortical seizures) or genetic approaches that we confirmed with whole‐cell patch clamp to substantially reduce I h current. We observed significant increases in the number of multiple movement responses evoked at single sites in motor maps to all three experimental manipulations in rats or mice. Global HCN1 knockout mice were less successful and exhibited atypical movements on a skilled‐motor learning task relative to wild‐type controls. Furthermore, in reaching‐proficient rats, reaching accuracy was reduced and forelimb movements were altered during infusion of ZD7288 within motor cortex. Thus, HCN channels play a critical role in the separation of overlapping movement responses and allow for successful reaching behaviours. These data provide a novel mechanism for the encoding of multiple

Nitrate decreases xanthine oxidoreductase-mediated nitrite reductase activity and attenuates vascular and blood pressure responses to nitrite.

Science.gov (United States)

Damacena-Angelis, Célio; Oliveira-Paula, Gustavo H; Pinheiro, Lucas C; Crevelin, Eduardo J; Portella, Rafael L; Moraes, Luiz Alberto B; Tanus-Santos, Jose E

2017-08-01

Nitrite and nitrate restore deficient endogenous nitric oxide (NO) production as they are converted back to NO, and therefore complement the classic enzymatic NO synthesis. Circulating nitrate and nitrite must cross membrane barriers to produce their effects and increased nitrate concentrations may attenuate the nitrite influx into cells, decreasing NO generation from nitrite. Moreover, xanthine oxidoreductase (XOR) mediates NO formation from nitrite and nitrate. However, no study has examined whether nitrate attenuates XOR-mediated NO generation from nitrite. We hypothesized that nitrate attenuates the vascular and blood pressure responses to nitrite either by interfering with nitrite influx into vascular tissue, or by competing with nitrite for XOR, thus inhibiting XOR-mediated NO generation. We used two independent vascular function assays in rats (aortic ring preparations and isolated mesenteric arterial bed perfusion) to examine the effects of sodium nitrate on the concentration-dependent responses to sodium nitrite. Both assays showed that nitrate attenuated the vascular responses to nitrite. Conversely, the aortic responses to the NO donor DETANONOate were not affected by sodium nitrate. Further confirming these results, we found that nitrate attenuated the acute blood pressure lowering effects of increasing doses of nitrite infused intravenously in freely moving rats. The possibility that nitrate could compete with nitrite and decrease nitrite influx into cells was tested by measuring the accumulation of nitrogen-15-labeled nitrite ( 15 N-nitrite) by aortic rings using ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS). Nitrate exerted no effect on aortic accumulation of 15 N-nitrite. Next, we used chemiluminescence-based NO detection to examine whether nitrate attenuates XOR-mediated nitrite reductase activity. Nitrate significantly shifted the Michaelis Menten saturation curve to the right, with a 3-fold increase in the

Music-Evoked Emotions—Current Studies

Science.gov (United States)

Schaefer, Hans-Eckhardt

2017-01-01

The present study is focused on a review of the current state of investigating music-evoked emotions experimentally, theoretically and with respect to their therapeutic potentials. After a concise historical overview and a schematic of the hearing mechanisms, experimental studies on music listeners and on music performers are discussed, starting with the presentation of characteristic musical stimuli and the basic features of tomographic imaging of emotional activation in the brain, such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), which offer high spatial resolution in the millimeter range. The progress in correlating activation imaging in the brain to the psychological understanding of music-evoked emotion is demonstrated and some prospects for future research are outlined. Research in psychoneuroendocrinology and molecular markers is reviewed in the context of music-evoked emotions and the results indicate that the research in this area should be intensified. An assessment of studies involving measuring techniques with high temporal resolution down to the 10 ms range, as, e.g., electroencephalography (EEG), event-related brain potentials (ERP), magnetoencephalography (MEG), skin conductance response (SCR), finger temperature, and goose bump development (piloerection) can yield information on the dynamics and kinetics of emotion. Genetic investigations reviewed suggest the heredity transmission of a predilection for music. Theoretical approaches to musical emotion are directed to a unified model for experimental neurological evidence and aesthetic judgment. Finally, the reports on musical therapy are briefly outlined. The study concludes with an outlook on emerging technologies and future research fields. PMID:29225563

Choline evokes fluid secretion by perfused rat mandibular gland without desensitization

DEFF Research Database (Denmark)

Murakami, M; Novak, I; Young, J A

1986-01-01

M and evoked secretory responses comparable with those of acetylcholine (0.05-1.0 microM) administered at similar Na concentrations. Continuous infusion of choline, in contrast to acetylcholine, did not lead to a fall off in the secretory response (desensitization or tachyphylaxis) until the choline...

Vascular adrenergic receptor responses in skeletal muscle in myotonic dystrophy

International Nuclear Information System (INIS)

Mechler, F.; Mastaglia, F.L.

1981-01-01

The pharmacological responses of vascular adrenergic receptors to intravenously administered epinephrine, phentolamine, and propranolol were assessed by measuring muscle blood flow (MBF) changes in the tibialis anterior muscle using the xenon 133 clearance technique and were compared in 8 normal subjects and 11 patients with myotonic dystrophy. In cases with advanced involvement of the muscle, the resting MBF was reduced and was not significantly altered by epinephrine before or after alpha- or beta-receptor blockade. In patients in whom the tibialis anterior muscle was normal or only minimally affected clinically, a paradoxical reduction in the epinephrine-induced increase in MBF was found after alpha blockade by phentolamine, and the epinephrine-induced MBF increase was not completely blocked by propranolol as in the normal subjects. These findings point to functional alteration in the properties of vascular adrenergic receptors in muscle in myotonic dystrophy. While this may be another manifestation of a widespread cell membrane defect in the disease, the possibility that the changes are secondary to the myotonic state cannot be excluded

Visual evoked potentials in patients after methanol poisoning.

Science.gov (United States)

Urban, Pavel; Zakharov, Sergey; Diblík, Pavel; Pelclová, Daniela; Ridzoň, Petr

2016-01-01

We report the results of the visual evoked potentials (VEP) examination in patients after severe poisoning by methanol. The group of 47 patients (38 males and 9 females) was assembled out of persons who survived an outbreak of poisoning by the methanol adulterated alcohol beverages, which happened in the Czech Republic in 2012-2013. The visual evoked potentials examination was performed using monocular checkerboard pattern-reversal stimulation. Two criteria of abnormality were chosen: missing evoked response, and wave P1 latency > 117 ms. Non-parametric statistical methods (median, range, and the median test) were used to analyze factors influencing the VEP abnormality. The visual evoked potential was abnormal in 20 patients (43%), 5 of them had normal visual acuity on the Snellen chart. The VEP abnormality did not correlate significantly with initial serum concentrations of methanol, formic acid or lactate; however, it showed statistically significant inverse relation to the initial serum pH: the subgroup with the abnormal VEP had significantly lower median pH in comparison with the subgroup with the normal VEP (7.16 vs. 7.34, p = 0.04). The abnormality was not related to chronic alcohol abuse. The visual evoked potentials examination appeared sensitive enough to detected even subclinical impairment of the optic system. Metabolic acidosis is likely to be the key factor related to the development of visual damage induced by methanol. The examination performed with a delay of 1-9 months after the poisoning documented the situation relatively early after the event. It is considered as a baseline for the planned long-term follow-up of the patients, which will make it possible to assess the dynamics of the observed changes, their reversibility, and the occurrence of potential late sequelae. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Role played by acid-sensitive ion channels in evoking the exercise pressor reflex.

Science.gov (United States)

Hayes, Shawn G; McCord, Jennifer L; Rainier, Jon; Liu, Zhuqing; Kaufman, Marc P

2008-10-01

The exercise pressor reflex arises from contracting skeletal muscle and is believed to play a role in evoking the cardiovascular responses to static exercise, effects that include increases in arterial pressure and heart rate. This reflex is believed to be evoked by the metabolic and mechanical stimulation of thin fiber muscle afferents. Lactic acid is known to be an important metabolic stimulus evoking the reflex. Until recently, the only antagonist for acid-sensitive ion channels (ASICs), the receptors to lactic acid, was amiloride, a substance that is also a potent antagonist for both epithelial sodium channels as well as voltage-gated sodium channels. Recently, a second compound, A-317567, has been shown to be an effective and selective antagonist to ASICs in vitro. Consequently, we measured the pressor responses to the static contraction of the triceps surae muscles in decerebrate cats before and after a popliteal arterial injection of A-317567 (10 mM solution; 0.5 ml). We found that this ASIC antagonist significantly attenuated by half (Pacid injection into the popliteal artery. In contrast, A-317567 had no effect on the pressor responses to tendon stretch, a pure mechanical stimulus, and to a popliteal arterial injection of capsaicin, which stimulated transient receptor potential vanilloid type 1 channels. We conclude that ASICs on thin fiber muscle afferents play a substantial role in evoking the metabolic component of the exercise pressor reflex.

Cardiovascular alterations at different stages of hypertension development during ethanol consumption: Time-course of vascular and autonomic changes

Energy Technology Data Exchange (ETDEWEB)

Crestani, Carlos C. [Department of Natural Active Principles and Toxicology, School of Pharmaceutical Sciences, Univ. Estadual Paulista—UNESP (Brazil); Lopes da Silva, Andréia [Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo (Brazil); Scopinho, América A. [Department of Pharmacology, School of Medicine of Ribeirao Preto, University of Sao Paulo (Brazil); Ruginsk, Silvia G.; Uchoa, Ernane T. [Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo (Brazil); Correa, Fernando M.A. [Department of Pharmacology, School of Medicine of Ribeirao Preto, University of Sao Paulo (Brazil); Elias, Lucila L.K.; Antunes-Rodrigues, José [Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo (Brazil); Resstel, Leonardo B.M., E-mail: leoresstel@yahoo.com.br [Department of Pharmacology, School of Medicine of Ribeirao Preto, University of Sao Paulo (Brazil)

2014-10-15

The aim of the present work was to establish a time-course correlation between vascular and autonomic changes that contribute to the development of hypertension during ethanol ingestion in rats. For this, male Wistar rats were subjected to the intake of increasing ethanol concentrations in their drinking water during four weeks. Ethanol effects were investigated at the end of each week. Mild hypertension was already observed at the first week of treatment, and a progressive blood pressure increase was observed along the evaluation period. Increased pressor response to phenylephrine was observed from first to fourth week. α{sub 1}-adrenoceptor protein in the mesenteric bed was enhanced at the first week, whereas β{sub 2}-adrenoceptor protein in the aorta was reduced after the second week. In the third week, ethanol intake facilitated the depressor response to sodium nitroprusside, whereas in the fourth week it reduced nitrate content in aorta and increased it plasma. The bradycardic component of the baroreflex was impaired, whereas baroreflex tachycardia was enhanced at the third and fourth weeks. AT{sub 1A} receptor and C-type natriuretic peptide (CNP) mRNAs in the nucleus tractus solitarius were increased at the fourth week. These findings suggest that increased vascular responsiveness to vasoconstrictor agents is possibly a link factor in the development and maintenance of the progressive hypertension induced by ethanol consumption. Additionally, baroreflex changes are possibly mediated by alterations in angiotensinergic mechanisms and CNP content within the brainstem, which contribute to maintaining the hypertensive state in later phases of ethanol ingestion. Facilitated vascular responsiveness to nitric oxide seems to counteract ethanol-induced hypertension. - Highlights: • Mild hypertension was observed during the entire period of ethanol ingestion. • Ethanol facilitated vascular reactivity to vasoactive agents. • Changes in baroreflex activity

Differences in receptor-evoked membrane electrical responses in native and mRNA-injected Xenopus oocytes.

Science.gov (United States)

Oron, Y; Gillo, B; Gershengorn, M C

1988-06-01

Xenopus laevis oocytes are giant cells suitable for studies of plasma membrane receptors and signal transduction pathways because of their capacity to express receptors after injection of heterologous mRNA. We studied depolarizing chloride currents evoked by acetylcholine (AcCho) in native oocytes ("intrinsic AcCho response"), by thyrotropin-releasing hormone (TRH) in oocytes injected with pituitary (GH3) cell RNA ("acquired TRH response"), and by AcCho in oocytes injected with rat brain RNA ("acquired AcCho response"). We found differences in the latencies and patterns of these responses and in the responsiveness to these agonists when applied to the animal or vegetal hemisphere, even though all of the responses are mediated by the same signal transduction pathway. The common intrinsic response to AcCho is characterized by minimal latency (0.86 +/- 0.05 sec), a rapid, transient depolarization followed by a distinct prolonged depolarization, and larger responses obtained after AcCho application at the vegetal rather than the animal hemisphere. By contrast, the acquired responses to TRH and AcCho are characterized by much longer latencies, 9.3 +/- 1.0 and 5.5 +/- 0.8 sec, respectively, and large rapid depolarizations followed by less distinct prolonged depolarizations. The responsiveness on the two hemispheres to TRH and AcCho in mRNA-injected oocytes is opposite to that for the common intrinsic AcCho response in that there is a much greater response when agonist is applied at the animal rather than the vegetal hemisphere. We suggest that the differences in these responses are caused by differences in the intrinsic properties of these receptors. Because different receptors appear to be segregated in the same oocyte in distinct localizations, Xenopus oocytes may be an important model system in which to study receptor sorting in polarized cells.

Evoked emotions predict food choice.

Science.gov (United States)

Dalenberg, Jelle R; Gutjar, Swetlana; Ter Horst, Gert J; de Graaf, Kees; Renken, Remco J; Jager, Gerry

2014-01-01

In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments. Therefore, the focus within recent studies shifted towards using emotion-profiling methods that successfully can discriminate between products that are equally liked. However, it is unclear how well scores from emotion-profiling methods predict actual food choice and/or consumption. To test this, we proposed to decompose emotion scores into valence and arousal scores using Principal Component Analysis (PCA) and apply Multinomial Logit Models (MLM) to estimate food choice using liking, valence, and arousal as possible predictors. For this analysis, we used an existing data set comprised of liking and food-evoked emotions scores from 123 participants, who rated 7 unlabeled breakfast drinks. Liking scores were measured using a 100-mm visual analogue scale, while food-evoked emotions were measured using 2 existing emotion-profiling methods: a verbal and a non-verbal method (EsSense Profile and PrEmo, respectively). After 7 days, participants were asked to choose 1 breakfast drink from the experiment to consume during breakfast in a simulated restaurant environment. Cross validation showed that we were able to correctly predict individualized food choice (1 out of 7 products) for over 50% of the participants. This number increased to nearly 80% when looking at the top 2 candidates. Model comparisons showed that evoked emotions better predict food choice than perceived liking alone. However, the strongest predictive strength was achieved by the combination of evoked emotions and liking. Furthermore we showed that non-verbal food-evoked emotion scores more accurately predict food choice than verbal food-evoked emotions scores.

Augmentation of radiation response with the vascular targeting agent ZD6126

International Nuclear Information System (INIS)

Hoang Tien; Huang Shyhmin; Armstrong, Eric; Eickhoff, Jens C.; Harari, Paul M.

2006-01-01

Purpose: To examine the antivascular and antitumor activity of the vascular targeting agent ZD6126 in combination with radiation in lung and head-and-neck (H and N) cancer models. The overall hypothesis was that simultaneous targeting of tumor cells (radiation) and tumor vasculature (ZD6126) might enhance tumor cell killing. Methods and Materials: A series of in vitro studies using human umbilical vein endothelial cells (HUVEC) and in vivo studies in athymic mice bearing human lung (H226) and H and N (squamous cell carcinoma [SCC]1, SCC6) tumor xenografts treated with ZD6126 and/or radiation were performed. Results: ZD6126 inhibited the capillary-like network formation in HUVEC. Treatment of HUVEC with ZD6126 resulted in cell cycle arrest in G2/M, with decrease of cells in S phase and proliferation inhibition in a dose-dependent manner. ZD6126 augmented the cell-killing effect of radiation and radiation-induced apoptosis in HUVEC. The combination of ZD6126 and radiation further decreased tumor vascularization in an in vivo Matrigel angiogenesis assay. In tumor xenografts, ZD6126 enhanced the antitumor activity of radiation, resulting in tumor growth delay. Conclusions: These preclinical studies suggest that ZD6126 can augment the radiation response of proliferating endothelial H and N and lung cancer cells. These results complement recent reports suggesting the potential value of combining radiation with vascular targeting/antiangiogenic agents

Comparing the Performance of Popular MEG/EEG Artifact Correction Methods in an Evoked-Response Study

DEFF Research Database (Denmark)

Haumann, Niels Trusbak; Parkkonen, Lauri; Kliuchko, Marina

2016-01-01

We here compared results achieved by applying popular methods for reducing artifacts in magnetoencephalography (MEG) and electroencephalography (EEG) recordings of the auditory evoked Mismatch Negativity (MMN) responses in healthy adult subjects. We compared the Signal Space Separation (SSS......) and temporal SSS (tSSS) methods for reducing noise from external and nearby sources. Our results showed that tSSS reduces the interference level more reliably than plain SSS, particularly for MEG gradiometers, also for healthy subjects not wearing strongly interfering magnetic material. Therefore, tSSS...... is recommended over SSS. Furthermore, we found that better artifact correction is achieved by applying Independent Component Analysis (ICA) in comparison to Signal Space Projection (SSP). Although SSP reduces the baseline noise level more than ICA, SSP also significantly reduces the signal—slightly more than...

Prior Expectations Evoke Stimulus Templates in the Primary Visual Cortex

NARCIS (Netherlands)

Kok, P.; Failing, F.M.; de Lange, F.P.

2014-01-01

Exposure to rhythmic stimulation results in facilitated responses to events that appear in-phase with the rhythm and modulation of anticipatory and target-evoked brain activity, presumably reflecting "exogenous," unintentional temporal expectations. However, the extent to which this effect is

Fast detection of unexpected sound intensity decrements as revealed by human evoked potentials.

Directory of Open Access Journals (Sweden)

Heike Althen

Full Text Available The detection of deviant sounds is a crucial function of the auditory system and is reflected by the automatically elicited mismatch negativity (MMN, an auditory evoked potential at 100 to 250 ms from stimulus onset. It has recently been shown that rarely occurring frequency and location deviants in an oddball paradigm trigger a more negative response than standard sounds at very early latencies in the middle latency response of the human auditory evoked potential. This fast and early ability of the auditory system is corroborated by the finding of neurons in the animal auditory cortex and subcortical structures, which restore their adapted responsiveness to standard sounds, when a rare change in a sound feature occurs. In this study, we investigated whether the detection of intensity deviants is also reflected at shorter latencies than those of the MMN. Auditory evoked potentials in response to click sounds were analyzed regarding the auditory brain stem response, the middle latency response (MLR and the MMN. Rare stimuli with a lower intensity level than standard stimuli elicited (in addition to an MMN a more negative potential in the MLR at the transition from the Na to the Pa component at circa 24 ms from stimulus onset. This finding, together with the studies about frequency and location changes, suggests that the early automatic detection of deviant sounds in an oddball paradigm is a general property of the auditory system.

Language related differences of the sustained response evoked by natural speech sounds.

Directory of Open Access Journals (Sweden)

Christina Siu-Dschu Fan

Full Text Available In tonal languages, such as Mandarin Chinese, the pitch contour of vowels discriminates lexical meaning, which is not the case in non-tonal languages such as German. Recent data provide evidence that pitch processing is influenced by language experience. However, there are still many open questions concerning the representation of such phonological and language-related differences at the level of the auditory cortex (AC. Using magnetoencephalography (MEG, we recorded transient and sustained auditory evoked fields (AEF in native Chinese and German speakers to investigate language related phonological and semantic aspects in the processing of acoustic stimuli. AEF were elicited by spoken meaningful and meaningless syllables, by vowels, and by a French horn tone. Speech sounds were recorded from a native speaker and showed frequency-modulations according to the pitch-contours of Mandarin. The sustained field (SF evoked by natural speech signals was significantly larger for Chinese than for German listeners. In contrast, the SF elicited by a horn tone was not significantly different between groups. Furthermore, the SF of Chinese subjects was larger when evoked by meaningful syllables compared to meaningless ones, but there was no significant difference regarding whether vowels were part of the Chinese phonological system or not. Moreover, the N100m gave subtle but clear evidence that for Chinese listeners other factors than purely physical properties play a role in processing meaningful signals. These findings show that the N100 and the SF generated in Heschl's gyrus are influenced by language experience, which suggests that AC activity related to specific pitch contours of vowels is influenced in a top-down fashion by higher, language related areas. Such interactions are in line with anatomical findings and neuroimaging data, as well as with the dual-stream model of language of Hickok and Poeppel that highlights the close and reciprocal interaction

Language related differences of the sustained response evoked by natural speech sounds.

Science.gov (United States)

Fan, Christina Siu-Dschu; Zhu, Xingyu; Dosch, Hans Günter; von Stutterheim, Christiane; Rupp, André

2017-01-01

In tonal languages, such as Mandarin Chinese, the pitch contour of vowels discriminates lexical meaning, which is not the case in non-tonal languages such as German. Recent data provide evidence that pitch processing is influenced by language experience. However, there are still many open questions concerning the representation of such phonological and language-related differences at the level of the auditory cortex (AC). Using magnetoencephalography (MEG), we recorded transient and sustained auditory evoked fields (AEF) in native Chinese and German speakers to investigate language related phonological and semantic aspects in the processing of acoustic stimuli. AEF were elicited by spoken meaningful and meaningless syllables, by vowels, and by a French horn tone. Speech sounds were recorded from a native speaker and showed frequency-modulations according to the pitch-contours of Mandarin. The sustained field (SF) evoked by natural speech signals was significantly larger for Chinese than for German listeners. In contrast, the SF elicited by a horn tone was not significantly different between groups. Furthermore, the SF of Chinese subjects was larger when evoked by meaningful syllables compared to meaningless ones, but there was no significant difference regarding whether vowels were part of the Chinese phonological system or not. Moreover, the N100m gave subtle but clear evidence that for Chinese listeners other factors than purely physical properties play a role in processing meaningful signals. These findings show that the N100 and the SF generated in Heschl's gyrus are influenced by language experience, which suggests that AC activity related to specific pitch contours of vowels is influenced in a top-down fashion by higher, language related areas. Such interactions are in line with anatomical findings and neuroimaging data, as well as with the dual-stream model of language of Hickok and Poeppel that highlights the close and reciprocal interaction between

The zinc transporter ZIP12 regulates the pulmonary vascular response to chronic hypoxia.

Science.gov (United States)

Zhao, Lan; Oliver, Eduardo; Maratou, Klio; Atanur, Santosh S; Dubois, Olivier D; Cotroneo, Emanuele; Chen, Chien-Nien; Wang, Lei; Arce, Cristina; Chabosseau, Pauline L; Ponsa-Cobas, Joan; Frid, Maria G; Moyon, Benjamin; Webster, Zoe; Aldashev, Almaz; Ferrer, Jorge; Rutter, Guy A; Stenmark, Kurt R; Aitman, Timothy J; Wilkins, Martin R

2015-08-20

The typical response of the adult mammalian pulmonary circulation to a low oxygen environment is vasoconstriction and structural remodelling of pulmonary arterioles, leading to chronic elevation of pulmonary artery pressure (pulmonary hypertension) and right ventricular hypertrophy. Some mammals, however, exhibit genetic resistance to hypoxia-induced pulmonary hypertension. We used a congenic breeding program and comparative genomics to exploit this variation in the rat and identified the gene Slc39a12 as a major regulator of hypoxia-induced pulmonary vascular remodelling. Slc39a12 encodes the zinc transporter ZIP12. Here we report that ZIP12 expression is increased in many cell types, including endothelial, smooth muscle and interstitial cells, in the remodelled pulmonary arterioles of rats, cows and humans susceptible to hypoxia-induced pulmonary hypertension. We show that ZIP12 expression in pulmonary vascular smooth muscle cells is hypoxia dependent and that targeted inhibition of ZIP12 inhibits the rise in intracellular labile zinc in hypoxia-exposed pulmonary vascular smooth muscle cells and their proliferation in culture. We demonstrate that genetic disruption of ZIP12 expression attenuates the development of pulmonary hypertension in rats housed in a hypoxic atmosphere. This new and unexpected insight into the fundamental role of a zinc transporter in mammalian pulmonary vascular homeostasis suggests a new drug target for the pharmacological management of pulmonary hypertension.

Auditory- and visual-evoked potentials in Mexican infants are not affected by maternal supplementation with 400 mg/d docosahexaenoic acid in the second half of pregnancy.

Science.gov (United States)

Stein, Aryeh D; Wang, Meng; Rivera, Juan A; Martorell, Reynaldo; Ramakrishnan, Usha

2012-08-01

The evidence relating prenatal supplementation with DHA to offspring neurological development is limited. We investigated the effect of prenatal DHA supplementation on infant brainstem auditory-evoked responses and visual- evoked potentials in a double-blind, randomized controlled trial in Cuernavaca, Mexico. Pregnant women were supplemented daily with 400 mg DHA or placebo from gestation wk 18-22 through delivery. DHA and placebo groups did not differ in maternal characteristics at randomization or infant characteristics at birth. Brainstem auditory-evoked responses were measured at 1 and 3 mo in 749 and 664 infants, respectively, and visual-evoked potentials were measured at 3 and 6 mo in 679 and 817 infants, respectively. Left-right brainstem auditory-evoked potentials were moderately correlated (range, 0.26-0.43; all P right visual-evoked potentials were strongly correlated (range, 0.79-0.94; all P 0.10). We conclude that DHA supplementation during pregnancy did not influence brainstem auditory-evoked responses at 1 and 3 mo or visual-evoked potentials at 3 and 6 mo.

Endogenous attention signals evoked by threshold contrast detection in human superior colliculus.

Science.gov (United States)

Katyal, Sucharit; Ress, David

2014-01-15

Human superior colliculus (SC) responds in a retinotopically selective manner when attention is deployed on a high-contrast visual stimulus using a discrimination task. To further elucidate the role of SC in endogenous visual attention, high-resolution fMRI was used to demonstrate that SC also exhibits a retinotopically selective response for covert attention in the absence of significant visual stimulation using a threshold-contrast detection task. SC neurons have a laminar organization according to their function, with visually responsive neurons present in the superficial layers and visuomotor neurons in the intermediate layers. The results show that the response evoked by the threshold-contrast detection task is significantly deeper than the response evoked by the high-contrast speed discrimination task, reflecting a functional dissociation of the attentional enhancement of visuomotor and visual neurons, respectively. Such a functional dissociation of attention within SC laminae provides a subcortical basis for the oculomotor theory of attention.

Characterization of music-evoked autobiographical memories.

Science.gov (United States)

Janata, Petr; Tomic, Stefan T; Rakowski, Sonja K

2007-11-01

Despite music's prominence in Western society and its importance to individuals in their daily lives, very little is known about the memories and emotions that are often evoked when hearing a piece of music from one's past. We examined the content of music-evoked autobiographical memories (MEAMs) using a novel approach for selecting stimuli from a large corpus of popular music, in both laboratory and online settings. A set of questionnaires probed the cognitive and affective properties of the evoked memories. On average, 30% of the song presentations evoked autobiographical memories, and the majority of songs also evoked various emotions, primarily positive, that were felt strongly. The third most common emotion was nostalgia. Analyses of written memory reports found both general and specific levels of autobiographical knowledge to be represented, and several social and situational contexts for memory formation were common across many memories. The findings indicate that excerpts of popular music serve as potent stimuli for studying the structure of autobiographical memories.

Calcium dynamics in vascular smooth muscle

OpenAIRE

Amberg, Gregory C.; Navedo, Manuel F.

2013-01-01

Smooth muscle cells are ultimately responsible for determining vascular luminal diameter and blood flow. Dynamic changes in intracellular calcium are a critical mechanism regulating vascular smooth muscle contractility. Processes influencing intracellular calcium are therefore important regulators of vascular function with physiological and pathophysiological consequences. In this review we discuss the major dynamic calcium signals identified and characterized in vascular smooth muscle cells....

Effects of whole-body cryotherapy duration on thermal and cardio-vascular response.

Science.gov (United States)

Fonda, Borut; De Nardi, Massimo; Sarabon, Nejc

2014-05-01

Whole-body cryotherapy (WBC) is the exposure of minimally dressed participants to very cold air, either in a specially designed chamber (cryo-chamber) or cabin (cryo-cabin), for a short period of time. Practitioners are vague when it comes to recommendations on the duration of a single session. Recommended exposure for cryo-chamber is 150s, but no empirically based recommendations are available for a cryo-cabin. Therefore the aim of this study was to examine thermal and cardio-vascular responses after 90, 120, 150 and 180s of WBC in a cryo-cabin. Our hypothesis was that skin temperature would be significantly lower after longer exposers. Twelve male participants (age 23.9±4.2 years) completed four WBC of different durations (90, 120, 150 and 180s) in a cryo-cabin. Thermal response, heart rate and blood pressure were measured prior, immediately after, 5min after and 30min after the session. Skin temperature differed significantly among different durations, except between 150 and 180s. There was no significant difference in heart rate and blood pressure. Thermal discomfort during a single session displayed a linear increase throughout the whole session. Our results indicate that practitioners and clinicians using cryo-cabin for WBC do not need to perform sessions longer than 150s. We have shown that longer sessions do not substantially affect thermal and cardio-vascular response, but do increase thermal discomfort. Copyright © 2014 Elsevier Ltd. All rights reserved.

Click-evoked otoacoustic emissions in children and adolescents with gender identity disorder

NARCIS (Netherlands)

Burke, Sarah M; Menks, Willeke M; Cohen-Kettenis, Peggy T; Klink, Daniel T; Bakker, J.

2014-01-01

Click-evoked otoacoustic emissions (CEOAEs) are echo-like sounds that are produced by the inner ear in response to click-stimuli. CEOAEs generally have a higher amplitude in women compared to men and neonates already show a similar sex difference in CEOAEs. Weaker responses in males are proposed to

Click-Evoked Otoacoustic Emissions in Children and Adolescents with Gender Identity Disorder

NARCIS (Netherlands)

Burke, S.M.; Menks, W.M.; Cohen-Kettenis, P.T.; Klink, D.T.; Bakker, J.

2014-01-01

Click-evoked otoacoustic emissions (CEOAEs) are echo-like sounds that are produced by the inner ear in response to click-stimuli. CEOAEs generally have a higher amplitude in women compared to men and neonates already show a similar sex difference in CEOAEs. Weaker responses in males are proposed to

Theories of schizophrenia: a genetic-inflammatory-vascular synthesis

Directory of Open Access Journals (Sweden)

Gottesman Irving I

2005-02-01

Full Text Available Abstract Background Schizophrenia, a relatively common psychiatric syndrome, affects virtually all brain functions yet has eluded explanation for more than 100 years. Whether by developmental and/or degenerative processes, abnormalities of neurons and their synaptic connections have been the recent focus of attention. However, our inability to fathom the pathophysiology of schizophrenia forces us to challenge our theoretical models and beliefs. A search for a more satisfying model to explain aspects of schizophrenia uncovers clues pointing to genetically mediated CNS microvascular inflammatory disease. Discussion A vascular component to a theory of schizophrenia posits that the physiologic abnormalities leading to illness involve disruption of the exquisitely precise regulation of the delivery of energy and oxygen required for normal brain function. The theory further proposes that abnormalities of CNS metabolism arise because genetically modulated inflammatory reactions damage the microvascular system of the brain in reaction to environmental agents, including infections, hypoxia, and physical trauma. Damage may accumulate with repeated exposure to triggering agents resulting in exacerbation and deterioration, or healing with their removal. There are clear examples of genetic polymorphisms in inflammatory regulators leading to exaggerated inflammatory responses. There is also ample evidence that inflammatory vascular disease of the brain can lead to psychosis, often waxing and waning, and exhibiting a fluctuating course, as seen in schizophrenia. Disturbances of CNS blood flow have repeatedly been observed in people with schizophrenia using old and new technologies. To account for the myriad of behavioral and other curious findings in schizophrenia such as minor physical anomalies, or reported decreased rates of rheumatoid arthritis and highly visible nail fold capillaries, we would have to evoke a process that is systemic such as the vascular

Limb venous distension evokes sympathetic activation via stimulation of the limb afferents in humans

Science.gov (United States)

Cui, Jian; McQuillan, Patrick M.; Blaha, Cheryl; Kunselman, Allen R.

2012-01-01

We have recently shown that a saline infusion in the veins of an arterially occluded human forearm evokes a systemic response with increases in muscle sympathetic nerve activity (MSNA) and blood pressure. In this report, we examined whether this response was a reflex that was due to venous distension. Blood pressure (Finometer), heart rate, and MSNA (microneurography) were assessed in 14 young healthy subjects. In the saline trial (n = 14), 5% forearm volume normal saline was infused in an arterially occluded arm. To block afferents in the limb, 90 mg of lidocaine were added to the same volume of saline in six subjects during a separate visit. To examine whether interstitial perfusion of normal saline alone induced the responses, the same volume of albumin solution (5% concentration) was infused in 11 subjects in separate studies. Lidocaine abolished the MSNA and blood pressure responses seen with saline infusion. Moreover, compared with the saline infusion, an albumin infusion induced a larger (MSNA: Δ14.3 ± 2.7 vs. Δ8.5 ± 1.3 bursts/min, P blood pressure responses. These data suggest that venous distension activates afferent nerves and evokes a powerful systemic sympathoexcitatory reflex. We posit that the venous distension plays an important role in evoking the autonomic adjustments seen with postural stress in human subjects. PMID:22707559

Controlled reperfusion decreased reperfusion induced oxidative stress and evoked inflammatory response in experimental aortic-clamping animal model.

Science.gov (United States)

Jancsó, G; Arató, E; Hardi, P; Nagy, T; Pintér, Ö; Fazekas, G; Gasz, B; Takacs, I; Menyhei, G; Kollar, L; Sínay, L

2016-09-12

Revascularization after long term aortic ischaemia in vascular surgery induces reperfusion injury accompanied with oxidative stress and inflammatory responses. The hypothesis of this study was that the aortic occlusion followed by controlled reperfusion (CR) can reduce the ischaemia-reperfusion injury, the systemic and local inflammatory response induced by oxidative stress.Animal model was used. animals underwent a 4-hour infrarenal aortic occlusion followed by continuous reperfusion. Treated group: animals were treated with CR: after a 4-hour infrarenal aortic occlusion we made CR for 30 minutes with the crystalloid reperfusion solution (blood: crystalloid solution ratio 1:1) on pressure 60 Hgmm. Blood samples were collected different times. The developing oxidative stress was detected by the plasma levels of malondialdehyde, reduced glutathion, thiol groups and superoxide dismutase. The inflammatory response was measured by phorbol myristate acetate-induced leukocyte reactive oxygen species production and detection of change in myeloperoxidase levels. The animals were anaesthetized one week after terminating ligation and biopsy was taken from quadriceps muscle and large parenchymal organs.CR significantly reduced the postischaemic oxydative stress and inflammatory responses in early reperfusion period. Pathophysiological results: The rate of affected muscle fibers by degeneration was significantly higher in the untreated animal group. The infiltration of leukocytes in muscle and parenchymal tissues was significantly lower in the treatedgroup.CR can improve outcome after acute lower-limb ischaemia. The results confirm that CR might be also a potential therapeutic approach in vascular surgery against reperfusion injury in acute limb ischaemia. Supported by OTKA K108596.

Functional imaging to monitor vascular and metabolic response in canine head and neck tumors during fractionated radiotherapy.

Science.gov (United States)

Rødal, Jan; Rusten, Espen; Søvik, Åste; Skogmo, Hege Kippenes; Malinen, Eirik

2013-10-01

Radiotherapy causes alterations in tumor biology, and non-invasive early assessment of such alterations may become useful for identifying treatment resistant disease. The purpose of the current work is to assess changes in vascular and metabolic features derived from functional imaging of canine head and neck tumors during fractionated radiotherapy. Material and methods. Three dogs with spontaneous head and neck tumors received intensity-modulated radiotherapy (IMRT). Contrast-enhanced cone beam computed tomography (CE-CBCT) at the treatment unit was performed at five treatment fractions. Dynamic (18)FDG-PET (D-PET) was performed prior to the start of radiotherapy, at mid-treatment and at 3-12 weeks after the completion of treatment. Tumor contrast enhancement in the CE-CBCT images was used as a surrogate for tumor vasculature. Vascular and metabolic tumor parameters were further obtained from the D-PET images. Changes in these tumor parameters were assessed, with emphasis on intra-tumoral distributions. Results. For all three patients, metabolic imaging parameters obtained from D-PET decreased from the pre- to the inter-therapy session. Correspondingly, for two of three patients, vascular imaging parameters obtained from both CE-CBCT and D-PET increased. Only one of the tumors showed a clear metabolic response after therapy. No systematic changes in the intra-tumor heterogeneity in the imaging parameters were found. Conclusion. Changes in vascular and metabolic parameters could be detected by the current functional imaging methods. Vascular tumor features from CE-CBCT and D-PET corresponded well. CE-CBCT is a potential method for easy response assessment when the patient is at the treatment unit.

The Involvement of Endogenous Neural Oscillations in the Processing of Rhythmic Input: More Than a Regular Repetition of Evoked Neural Responses

Science.gov (United States)

Zoefel, Benedikt; ten Oever, Sanne; Sack, Alexander T.

2018-01-01

It is undisputed that presenting a rhythmic stimulus leads to a measurable brain response that follows the rhythmic structure of this stimulus. What is still debated, however, is the question whether this brain response exclusively reflects a regular repetition of evoked responses, or whether it also includes entrained oscillatory activity. Here we systematically present evidence in favor of an involvement of entrained neural oscillations in the processing of rhythmic input while critically pointing out which questions still need to be addressed before this evidence could be considered conclusive. In this context, we also explicitly discuss the potential functional role of such entrained oscillations, suggesting that these stimulus-aligned oscillations reflect, and serve as, predictive processes, an idea often only implicitly assumed in the literature. PMID:29563860

Inflammation and vascular responses to acute mental stress : implications for the triggering of myocardial infarction

NARCIS (Netherlands)

Paine, N.J.; Bosch, J.A.; Veldhuijzen Van Zanten, J.J.C.S.

2012-01-01

There is evidence that mental stress can trigger myocardial infarction. Even though the underlying mechanisms remain to be determined, both inflammation and vascular responses to mental stress have been implicated as contributing factors. This review explores the effects of inflammation on the

Effects of insomnia disorder and knee osteoarthritis on resting and pain-evoked inflammatory markers.

Science.gov (United States)

Quartana, Phillip J; Finan, Patrick H; Page, Gayle G; Smith, Michael T

2015-07-01

Osteoarthritis is the most prevalent arthritic condition. Systemic inflammatory cytokines appear to have an important role in the onset and maintenance of the disease. Sleep disturbances are prevalent in osteoarthritis and associated with alterations in systemic inflammatory cytokines, suggesting a common pathophysiology across these conditions. A comparative investigation of the effects of insomnia disorder and osteoarthritis on pain-evoked cytokine responses has yet to be undertaken. We examined the influence of symptomatic knee osteoarthritis and insomnia disorder on resting C-reactive protein (CRP), interleukin (IL)-6, and IL-10 levels, and pain-evoked IL-6 and IL-10 responses. Participants were N=117 older adults (mean age=59.7years; 61.8% women) rigorously evaluated for knee osteoarthritis and insomnia disorder using established diagnostic guidelines. Results revealed no association of osteoarthritis or insomnia disorder with CRP. Resting IL-6 was greater in osteoarthritis participants versus those without osteoarthritis, although this association was largely attributable to BMI. IL-10 was highest among participants with osteoarthritis or insomnia disorder. Growth curve modeling revealed that participants with insomnia disorder had greater pain-evoked IL-6 responses than participants without insomnia disorder or osteoarthritis. These findings highlight the utility of laboratory pain testing methods for understanding individual differences in inflammatory cytokines. Moreover, our findings provide evidence for amplified pain-evoked pro-inflammatory cytokine reactivity among older adults with clinically diagnosed insomnia disorder, even after controlling for individual differences in BMI and age. Additional research will be required determine whether an amplified pain-related cytokine response contributes to OA, and possibly other age-related disease, associated with insomnia disorder. Published by Elsevier Inc.

Modulation of electric brain responses evoked by pitch deviants through transcranial direct current stimulation.

Science.gov (United States)

Royal, Isabelle; Zendel, Benjamin Rich; Desjardins, Marie-Ève; Robitaille, Nicolas; Peretz, Isabelle

2018-01-31

Congenital amusia is a neurodevelopmental disorder, characterized by a difficulty detecting pitch deviation that is related to abnormal electrical brain responses. Abnormalities found along the right fronto-temporal pathway between the inferior frontal gyrus (IFG) and the auditory cortex (AC) are the likely neural mechanism responsible for amusia. To investigate the causal role of these regions during the detection of pitch deviants, we applied cathodal (inhibitory) transcranial direct current stimulation (tDCS) over right frontal and right temporal regions during separate testing sessions. We recorded participants' electrical brain activity (EEG) before and after tDCS stimulation while they performed a pitch change detection task. Relative to a sham condition, there was a decrease in P3 amplitude after cathodal stimulation over both frontal and temporal regions compared to pre-stimulation baseline. This decrease was associated with small pitch deviations (6.25 cents), but not large pitch deviations (200 cents). Overall, this demonstrates that using tDCS to disrupt regions around the IFG and AC can induce temporary changes in evoked brain activity when processing pitch deviants. These electrophysiological changes are similar to those observed in amusia and provide causal support for the connection between P3 and fronto-temporal brain regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Uric acid promotes vascular stiffness, maladaptive inflammatory responses and proteinuria in western diet fed mice.

Science.gov (United States)

Aroor, Annayya R; Jia, Guanghong; Habibi, Javad; Sun, Zhe; Ramirez-Perez, Francisco I; Brady, Barron; Chen, Dongqing; Martinez-Lemus, Luis A; Manrique, Camila; Nistala, Ravi; Whaley-Connell, Adam T; Demarco, Vincent G; Meininger, Gerald A; Sowers, James R

2017-09-01

Aortic vascular stiffness has been implicated in the development of cardiovascular disease (CVD) and chronic kidney disease (CKD) in obese individuals. However, the mechanism promoting these adverse effects are unclear. In this context, promotion of obesity through consumption of a western diet (WD) high in fat and fructose leads to excess circulating uric acid. There is accumulating data implicating elevated uric acid in the promotion of CVD and CKD. Accordingly, we hypothesized that xanthine oxidase(XO) inhibition with allopurinol would prevent a rise in vascular stiffness and proteinuria in a translationally relevant model of WD-induced obesity. Four-week-old C57BL6/J male mice were fed a WD with excess fat (46%) and fructose (17.5%) with or without allopurinol (125mg/L in drinking water) for 16weeks. Aortic endothelial and extracellular matrix/vascular smooth muscle stiffness was evaluated by atomic force microscopy. Aortic XO activity, 3-nitrotyrosine (3-NT) and aortic endothelial sodium channel (EnNaC) expression were evaluated along with aortic expression of inflammatory markers. In the kidney, expression of toll like receptor 4 (TLR4) and fibronectin were assessed along with evaluation of proteinuria. XO inhibition significantly attenuated WD-induced increases in plasma uric acid, vascular XO activity and oxidative stress, in concert with reductions in proteinuria. Further, XO inhibition prevented WD-induced increases in aortic EnNaC expression and associated endothelial and subendothelial stiffness. XO inhibition also reduced vascular pro-inflammatory and maladaptive immune responses induced by consumption of a WD. XO inhibition also decreased WD-induced increases in renal TLR4 and fibronectin that associated proteinuria. Consumption of a WD leads to elevations in plasma uric acid, increased vascular XO activity, oxidative stress, vascular stiffness, and proteinuria all of which are attenuated with allopurinol administration. Copyright © 2017 Elsevier Inc

A comparison of auditory evoked potentials to acoustic beats and to binaural beats

OpenAIRE

Pratt, H; Starr, A; Michalewski, HJ; Dimitrijevic, A; Bleich, N; Mittelman, N

2010-01-01

The purpose of this study was to compare cortical brain responses evoked by amplitude modulated acoustic beats of 3 and 6 Hz in tones of 250 and 1000 Hz with those evoked by their binaural beats counterparts in unmodulated tones to indicate whether the cortical processes involved differ. Event-related potentials (ERPs) were recorded to 3- and 6-Hz acoustic and binaural beats in 2000 ms duration 250 and 1000 Hz tones presented with approximately 1 s intervals. Latency, amplitude and source cur...

[Multicentric hyaline vascular Castleman's disease. A POEMS type variant].

Science.gov (United States)

Gracia-Ramos, Abraham Edgar; Cruz-Domínguez, María del Pilar; Vera-Lastra, Olga Lidia

2013-01-01

Castleman's disease is an atypical lymphoproliferative disorder which may be compatible with paraneoplastic manifestations of POEMS syndrome. a 53 year old man with a history of type 2 diabetes, hypothyroidism and Addison's disease presented with numbness and weakness in limbs, dyspnea, skin hardening, Raynaud's phenomenon, weight loss and fatigue. A physical exam showed tachypnea, generalized cutaneous hyperpigmentation and skin hardening of extremities, muscle weakness, hypoesthesia and hyporeflexia. Laboratory showed hyperprolactinemia, low testosterone, hypothyroidism and Addison's disease. Electrophoresis of proteins showed polyclonal hypergammaglobulinemia. Somatosensory evoked potentials reported peripheral neuropathy and severe axonal polyneuropathy by electromyography. Chest X-rays showed bilateral reticular infiltrates and mediastinal widening. An echocardiogram displayed moderate pulmonary hypertension. Skin biopsy had no evidence of scleroderma. CT reported axillar, mediastinal and retroperitoneal nodes. The mediastinal lesion biopsy reported hyaline vascular Castleman's disease, multicentric variety. He was treated with rituximab. the case meet criteria for multicentric hyaline vascular Castleman's disease, POEMS variant, treated with rituximab.

Pain Processing and Vegetative Dysfunction in Fibromyalgia: A Study by Sympathetic Skin Response and Laser Evoked Potentials

Directory of Open Access Journals (Sweden)

Marina de Tommaso

2017-01-01

Full Text Available Background. A dysfunction of pain processing at central and peripheral levels was reported in fibromyalgia (FM. We aimed to correlate laser evoked potentials (LEPs, Sympathetic Skin Response (SSR, and clinical features in FM patients. Methods. Fifty FM patients and 30 age-matched controls underwent LEPs and SSR by the right hand and foot. The clinical evaluation included FM disability (FIQ and severity scores (WPI, anxiety (SAS and depression (SDS scales, and questionnaires for neuropathic pain (DN4. Results. The LEP P2 latency and amplitude and the SSR latency were increased in FM group. This latter feature was more evident in anxious patients. The LEPs habituation was reduced in FM patients and correlated to pain severity scores. In a significant number of patients (32% with higher DN4 and FIQ scores, SSR or LEP responses were absent. Conclusions. LEPs and SSR might contribute to clarifying the peripheral and central nervous system involvement in FM patients.

Guanfacine potentiates the activation of prefrontal cortex evoked by warning signals.

Science.gov (United States)

Clerkin, Suzanne M; Schulz, Kurt P; Halperin, Jeffrey M; Newcorn, Jeffrey H; Ivanov, Iliyan; Tang, Cheuk Y; Fan, Jin

2009-08-15

Warning signals evoke an alert state of readiness that prepares for a rapid response by priming a thalamo-frontal-striatal network that includes the dorsolateral prefrontal cortex (DLPFC). Animal models indicate that noradrenergic input is essential for this stimulus-driven activation of DLPFC, but the precise mechanisms involved have not been determined. We tested the role that postsynaptic alpha(2A) adrenoceptors play in the activation of DLPFC evoked by warning cues using a placebo-controlled challenge with the alpha(2A) agonist guanfacine. Sixteen healthy young adults were scanned twice with event-related functional magnetic resonance imaging (fMRI), while performing a simple cued reaction time (RT) task following administration of a single dose of oral guanfacine (1 mg) and placebo in counterbalanced order. The RT task temporally segregates the neural effects of warning cues and motor responses and minimizes mnemonic demands. Warning cues produced a marked reduction in RT accompanied by significant activation in a distributed thalamo-frontal-striatal network, including bilateral DLPFC. Guanfacine selectively increased the cue-evoked activation of the left DLPFC and right anterior cerebellum, although this increase was not accompanied by further reductions in RT. The effects of guanfacine on DLPFC activation were specifically associated with the warning cue and were not seen for visual- or target-related activation. Guanfacine produced marked increases in the cue-evoked activation of DLPFC that correspond to the well-described actions of postsynaptic alpha(2) adrenoceptor stimulation. The current procedures provide an opportunity to test postsynaptic alpha(2A) adrenoceptor function in the prefrontal cortex in the pathophysiology of several psychiatric disorders.

Early changes of auditory brain stem evoked response after radiotherapy for nasopharyngeal carcinoma - a prospective study

Energy Technology Data Exchange (ETDEWEB)

Lau, S K; Wei, W I; Sham, J S.T.; Choy, D T.K.; Hui, Y [Queen Mary Hospital, Hong Kong (Hong Kong)

1992-10-01

A prospective study of the effect of radiotherapy for nasopharyngeal carcinoma on hearing was carried out on 49 patients who had pure tone, impedance audiometry and auditory brain stem evoked response (ABR) recordings before, immediately, three, six and 12 months after radiotherapy. Fourteen patients complained of intermittent tinnitus after radiotherapy. We found that 11 initially normal ears of nine patients developed a middle ear effusion, three to six months after radiotherapy. There was mixed sensorineural and conductive hearing impairment after radiotherapy. Persistent impairment of ABR was detected immediately after completion of radiotherapy. The waves I-III and I-V interpeak latency intervals were significantly prolonged one year after radiotherapy. The study shows that radiotherapy for nasopharyngeal carcinoma impairs hearing by acting on the middle ear, the cochlea and the brain stem auditory pathway. (Author).

Early changes of auditory brain stem evoked response after radiotherapy for nasopharyngeal carcinoma - a prospective study

International Nuclear Information System (INIS)

Lau, S.K.; Wei, W.I.; Sham, J.S.T.; Choy, D.T.K.; Hui, Y.

1992-01-01

A prospective study of the effect of radiotherapy for nasopharyngeal carcinoma on hearing was carried out on 49 patients who had pure tone, impedance audiometry and auditory brain stem evoked response (ABR) recordings before, immediately, three, six and 12 months after radiotherapy. Fourteen patients complained of intermittent tinnitus after radiotherapy. We found that 11 initially normal ears of nine patients developed a middle ear effusion, three to six months after radiotherapy. There was mixed sensorineural and conductive hearing impairment after radiotherapy. Persistent impairment of ABR was detected immediately after completion of radiotherapy. The waves I-III and I-V interpeak latency intervals were significantly prolonged one year after radiotherapy. The study shows that radiotherapy for nasopharyngeal carcinoma impairs hearing by acting on the middle ear, the cochlea and the brain stem auditory pathway. (Author)

TH-E-BRF-03: A Multivariate Interaction Model for Assessment of Hippocampal Vascular Dose-Response and Early Prediction of Radiation-Induced Neurocognitive Dysfunction

Energy Technology Data Exchange (ETDEWEB)

Farjam, R; Pramanik, P; Srinivasan, A; Chapman, C; Tsien, C; Lawrence, T; Cao, Y [University of Michigan, Ann Arbor, MI (United States)

2014-06-15

Purpose: Vascular injury could be a cause of hippocampal dysfunction leading to late neurocognitive decline in patients receiving brain radiotherapy (RT). Hence, our aim was to develop a multivariate interaction model for characterization of hippocampal vascular dose-response and early prediction of radiation-induced late neurocognitive impairments. Methods: 27 patients (17 males and 10 females, age 31–80 years) were enrolled in an IRB-approved prospective longitudinal study. All patients were diagnosed with a low-grade glioma or benign tumor and treated by 3-D conformal or intensity-modulated RT with a median dose of 54 Gy (50.4–59.4 Gy in 1.8− Gy fractions). Six DCE-MRI scans were performed from pre-RT to 18 months post-RT. DCE data were fitted to the modified Toft model to obtain the transfer constant of gadolinium influx from the intravascular space into the extravascular extracellular space, Ktrans, and the fraction of blood plasma volume, Vp. The hippocampus vascular property alterations after starting RT were characterized by changes in the hippocampal mean values of, μh(Ktrans)τ and μh(Vp)τ. The dose-response, Δμh(Ktrans/Vp)pre->τ, was modeled using a multivariate linear regression considering integrations of doses with age, sex, hippocampal laterality and presence of tumor/edema near a hippocampus. Finally, the early vascular dose-response in hippocampus was correlated with neurocognitive decline 6 and 18 months post-RT. Results: The μh(Ktrans) increased significantly from pre-RT to 1 month post-RT (p<0.0004). The multivariate model showed that the dose effect on Δμh(Ktrans)pre->1M post-RT was interacted with sex (p<0.0007) and age (p<0.00004), with the dose-response more pronounced in older females. Also, the vascular dose-response in the left hippocampus of females was significantly correlated with memory function decline at 6 (r = − 0.95, p<0.0006) and 18 (r = −0.88, p<0.02) months post-RT. Conclusion: The hippocampal vascular

TH-E-BRF-03: A Multivariate Interaction Model for Assessment of Hippocampal Vascular Dose-Response and Early Prediction of Radiation-Induced Neurocognitive Dysfunction

International Nuclear Information System (INIS)

Farjam, R; Pramanik, P; Srinivasan, A; Chapman, C; Tsien, C; Lawrence, T; Cao, Y

2014-01-01

Purpose: Vascular injury could be a cause of hippocampal dysfunction leading to late neurocognitive decline in patients receiving brain radiotherapy (RT). Hence, our aim was to develop a multivariate interaction model for characterization of hippocampal vascular dose-response and early prediction of radiation-induced late neurocognitive impairments. Methods: 27 patients (17 males and 10 females, age 31–80 years) were enrolled in an IRB-approved prospective longitudinal study. All patients were diagnosed with a low-grade glioma or benign tumor and treated by 3-D conformal or intensity-modulated RT with a median dose of 54 Gy (50.4–59.4 Gy in 1.8− Gy fractions). Six DCE-MRI scans were performed from pre-RT to 18 months post-RT. DCE data were fitted to the modified Toft model to obtain the transfer constant of gadolinium influx from the intravascular space into the extravascular extracellular space, Ktrans, and the fraction of blood plasma volume, Vp. The hippocampus vascular property alterations after starting RT were characterized by changes in the hippocampal mean values of, μh(Ktrans)τ and μh(Vp)τ. The dose-response, Δμh(Ktrans/Vp)pre->τ, was modeled using a multivariate linear regression considering integrations of doses with age, sex, hippocampal laterality and presence of tumor/edema near a hippocampus. Finally, the early vascular dose-response in hippocampus was correlated with neurocognitive decline 6 and 18 months post-RT. Results: The μh(Ktrans) increased significantly from pre-RT to 1 month post-RT (p<0.0004). The multivariate model showed that the dose effect on Δμh(Ktrans)pre->1M post-RT was interacted with sex (p<0.0007) and age (p<0.00004), with the dose-response more pronounced in older females. Also, the vascular dose-response in the left hippocampus of females was significantly correlated with memory function decline at 6 (r = − 0.95, p<0.0006) and 18 (r = −0.88, p<0.02) months post-RT. Conclusion: The hippocampal vascular

Response of photosynthetic carbon gain to ecosystem retrogression of vascular plants and mosses in the boreal forest.

Science.gov (United States)

Bansal, Sheel; Nilsson, Marie-Charlotte; Wardle, David A

2012-07-01

In the long-term absence of rejuvenating disturbances, forest succession frequently proceeds from a maximal biomass phase to a retrogressive phase characterized by reduced nutrient availability [notably nitrogen (N) and phosphorus (P)] and net primary productivity. Few studies have considered how retrogression induces changes in ecophysiological responses associated with photosynthetic carbon (C) gain, and only for trees. We tested the hypothesis that retrogression would negatively impact photosynthetic C gain of four contrasting species, and that this impact would be greater for vascular plants (i.e., trees and shrubs) than for non-vascular plants (i.e., mosses). We used a 5,000-year-old chronosequence of forested islands in Sweden, where retrogression occurs in the long-term absence of lightning-ignited wildfires. Despite fundamental differences in plant form and ecological niche among species, vascular plants and mosses showed similar ecophysiological responses to retrogression. The most common effects of retrogression were reductions in photosynthesis and respiration per unit foliar N, increases in foliar N, δ(13)C and δ(15)N, and decreases in specific leaf areas. In contrast, photosynthesis per unit mass or area generally did not change along the chronosequence, but did vary many-fold between vascular plants and mosses. The consistent increases in foliar N without corresponding increases in mass- or area-based photosynthesis suggest that other factor(s), such as P co-limitation, light conditions or water availability, may co-regulate C gain in retrogressive boreal forests. Against our predictions, traits of mosses associated with C and N were generally highly responsive to retrogression, which has implications for how mosses influence ecosystem processes in boreal forests.

Not all reading is alike: Task modulation of magnetic evoked response to visual word

Directory of Open Access Journals (Sweden)

Pavlova A. A.

2017-09-01

Full Text Available Background. Previous studies have shown that brain response to a written word depends on the task: whether the word is a target in a version of lexical decision task or should be read silently. Although this effect has been interpreted as an evidence for an interaction between word recognition processes and task demands, it also may be caused by greater attention allocation to the target word. Objective. We aimed to examine the task effect on brain response evoked by non- target written words. Design. Using MEG and magnetic source imaging, we compared spatial-temporal pattern of brain response elicited by a noun cue when it was read silently either without additional task (SR or with a requirement to produce an associated verb (VG. Results.The task demands penetrated into early (200-300 ms and late (500-800 ms stages of a word processing by enhancing brain response under VG versus SR condition. The cortical sources of the early response were localized to bilateral inferior occipitotemporal and anterior temporal cortex suggesting that more demanding VG task required elaborated lexical-semantic analysis. The late effect was observed in the associative auditory areas in middle and superior temporal gyri and in motor representation of articulators. Our results suggest that a remote goal plays a pivotal role in enhanced recruitment of cortical structures underlying orthographic, semantic and sensorimotor dimensions of written word perception from the early processing stages. Surprisingly, we found that to fulfil a more challenging goal the brain progressively engaged resources of the right hemisphere throughout all stages of silent reading. Conclusion. Our study demonstrates that a deeper processing of linguistic input amplifies activation of brain areas involved in integration of speech perception and production. This is consistent with theories that emphasize the role of sensorimotor integration in speech understanding.

Injuries to the vascular endothelium: vascular wall and endothelial dysfunction.

Science.gov (United States)

Fisher, Mark

2008-01-01

Vascular endothelial injury has multiple elements, and this article focuses on ischemia-related processes that have particular relevance to ischemic stroke. Distinctions between necrotic and apoptotic cell death provide a basic science context in which to better understand the significance of classical core and penumbra concepts of acute stroke, with apoptotic processes particularly prominent in the penumbra. The mitochondria are understood to serve as a reservoir of proteins that mediate apoptosis. Oxidative stress pathways generating reactive oxygen species (ROS) are prominent in endothelial injury, both ischemic and nonischemic, with prominent roles of enzyme- and nonenzymemediated pathways; mitochondria once again have a critical role, particularly in the nonenzymatic pathways generating ROS. Inflammation also contributes to vascular endothelial injury, and endothelial cells have the capacity to rapidly increase expression of inflammatory mediators following ischemic challenge; this leads to enhanced leukocyte-endothelial interactions mediated by selectins and adhesion molecules. Preconditioning consists of a minor version of an injurious event, which in turn may protect vascular endothelium from injury following a more substantial event. Presence of the blood-brain barrier creates unique responses to endothelial injury, with permeability changes due to impairment of endothelial-matrix interactions compounding altered vasomotor tone and tissue perfusion mediated by nitric oxide. Pharmacological protection against vascular endothelial injury can be provided by several of the phosphodiesterases (cilostazol and dipyridamole), along with statins. Optimal clinical responses for protection of brain vascular endothelium may use preconditioning as a model, and will likely require combined protection against apoptosis, ROS, and inflammation.

Identification of chemical components of combustion emissions that affect pro-atherosclerotic vascular responses in mice.

Science.gov (United States)

Seilkop, Steven K; Campen, Matthew J; Lund, Amie K; McDonald, Jacob D; Mauderly, Joe L

2012-04-01

Combustion emissions cause pro-atherosclerotic responses in apolipoprotein E-deficient (ApoE/⁻) mice, but the causal components of these complex mixtures are unresolved. In studies previously reported, ApoE⁻/⁻ mice were exposed by inhalation 6 h/day for 50 consecutive days to multiple dilutions of diesel or gasoline exhaust, wood smoke, or simulated "downwind" coal emissions. In this study, the analysis of the combined four-study database using the Multiple Additive Regression Trees (MART) data mining approach to determine putative causal exposure components regardless of combustion source is reported. Over 700 physical-chemical components were grouped into 45 predictor variables. Response variables measured in aorta included endothelin-1, vascular endothelin growth factor, three matrix metalloproteinases (3, 7, 9), metalloproteinase inhibitor 2, heme-oxygenase-1, and thiobarbituric acid reactive substances. Two or three predictors typically explained most of the variation in response among the experimental groups. Overall, sulfur dioxide, ammonia, nitrogen oxides, and carbon monoxide were most highly predictive of responses, although their rankings differed among the responses. Consistent with the earlier finding that filtration of particles had little effect on responses, particulate components ranked third to seventh in predictive importance for the eight response variables. MART proved useful for identifying putative causal components, although the small number of pollution mixtures (4) can provide only suggestive evidence of causality. The potential independent causal contributions of these gases to the vascular responses, as well as possible interactions among them and other components of complex pollutant mixtures, warrant further evaluation.

Analysis of electrically evoked compound action potential of the auditory nerve in children with bilateral cochlear implants.

Science.gov (United States)

Caldas, Fernanda Ferreira; Cardoso, Carolina Costa; Barreto, Monique Antunes de Souza Chelminski; Teixeira, Marina Santos; Hilgenberg, Anacléia Melo da Silva; Serra, Lucieny Silva Martins; Bahmad Junior, Fayez

2016-01-01

The cochlear implant device has the capacity to measure the electrically evoked compound action potential of the auditory nerve. The neural response telemetry is used in order to measure the electrically evoked compound action potential of the auditory nerve. To analyze the electrically evoked compound action potential, through the neural response telemetry, in children with bilateral cochlear implants. This is an analytical, prospective, longitudinal, historical cohort study. Six children, aged 1-4 years, with bilateral cochlear implant were assessed at five different intervals during their first year of cochlear implant use. There were significant differences in follow-up time (p=0.0082) and electrode position (p=0.0019) in the T-NRT measure. There was a significant difference in the interaction between time of follow-up and electrode position (p=0.0143) when measuring the N1-P1 wave amplitude between the three electrodes at each time of follow-up. The electrically evoked compound action potential measurement using neural response telemetry in children with bilateral cochlear implants during the first year of follow-up was effective in demonstrating the synchronized bilateral development of the peripheral auditory pathways in the studied population. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

The relation of ongoing brain activity, evoked neural responses, and cognition

Directory of Open Access Journals (Sweden)

Sepideh Sadaghiani

2010-06-01

Full Text Available Ongoing brain activity has been observed since the earliest neurophysiological recordings and is found over a wide range of temporal and spatial scales. It is characterized by remarkably large spontaneous modulations. Here, we review evidence for the functional role of these ongoing activity fluctuations and argue that they constitute an essential property of the neural architecture underlying cognition. The role of spontaneous activity fluctuations is probably best understood when considering both their spatiotemporal structure and their functional impact on cognition. We first briefly argue against a ‘segregationist’ view on ongoing activity, both in time and space, countering this view with an emphasis on integration within a hierarchical spatiotemporal organization of intrinsic activity. We then highlight the flexibility and context-sensitivity of intrinsic functional connectivity that suggest its involvement in functionally relevant information processing. This role in information processing is pursued by reviewing how ongoing brain activity interacts with afferent and efferent information exchange of the brain with its environment. We focus on the relationship between the variability of ongoing and evoked brain activity, and review recent reports that tie ongoing brain activity fluctuations to variability in human perception and behavior. Finally, these observations are discussed within the framework of the free-energy principle which – applied to human brain function - provides a theoretical account for a non-random, coordinated interaction of ongoing and evoked activity in perception and behaviour.

Pattern visual evoked potentials in malingering.

Science.gov (United States)

Nakamura, A; Akio, T; Matsuda, E; Wakami, Y

2001-03-01

We previously developed a new method for estimating objective visual acuity by means of pattern visual evoked potentials (PVEP). In this study, this method was applied to the diagnosis of malingering. Six patients ranging in age from 40 to 54 years (mean 47 years) with suspected malingering were evaluated by means of the visual evoked potential test, optokinetic nystagmus (OKN) inhibition test, and the visual field test. In the PVEP study, the stimulus consisted of black and white checkerboards (39', 26', 15', and 9') with a visual angle of 8 degrees, contrast level of 15%, and a frequency of 0.7 Hz. One hundred PVEP responses were averaged per session. Routine ophthalmic examinations were normal in all patients. Five patients had a tubularly constricted visual field, and the remaining patient had a normal visual field. The objective visual acuities of the six patients estimated from PVEP were better than their subjective visual acuities estimated with Landolt rings. Among a variety of psychophysical and electrophysiologic ancillary tests, we consider our PVEP method a useful method for objectively determining visual acuity in a patient with signs of ocular malingering.

Neurotology findings in patients with diagnosis of vascular loop of cranial nerves VIII in magnetic resonance imaging

Directory of Open Access Journals (Sweden)

Grocoske, Francisco Luiz Busato

Full Text Available Introduction: The vascular compression by redundant vessels under the VIII cranial nerves has been studied since the 80's, and many authors proposed correlations between the compression and the otoneurological findings (vertigo, tinnitus, hypoacusis, audiometry and electrophysiological findings. Objective: Analyze and correlate the different signs and otoneurological symptoms, the audiological findings and its incidence over individuals with Vascular Loop (VL diagnosis of VIII cranial nerves by magnetic resonance imaging (MRI. Method: Retrospective study through the analysis of medical records of 47 patients attended in the otoneurology clinic of Clinical Hospital of UFPR. All the patients have MRI exams with compatible pictures of VL of the VIII cranial nerves. Results: The tinnitus was the most frequent symptom, in 83% of the patients, followed by hypoacusis (60% and vertigo (36%. The audiometry presented alterations in 89%, the brainstem evoked auditory potential in 33% and the vecto-electronystagmography in 17% of the patients. Was not found statistically significant relation between the buzz or hypoacusis, and the presence of VL in MRI. Only 36% of patients had complaints of vertigo, the main symptom described in theory of vascular compression of the VIII pair of nerve. As in the audiometry and in brainstem evoked auditory potential was not found a statistically significant relation between the exam and the presence of the VL in the RMI. Conclusion: The results show independence between the findings of the RMI, clinical picture and audiological results (p>0,05 suggesting that there are no exclusive and direct relation between the diagnosis of vascular loop in the MRI and the clinical picture matching.

Normalization reduces intersubject variability in cervical vestibular evoked myogenic potentials.

Science.gov (United States)

van Tilburg, Mark J; Herrmann, Barbara S; Guinan, John J; Rauch, Steven D

2014-09-01

Cervical vestibular evoked myogenic potentials are used to assess saccular and inferior vestibular nerve function. Normalization of the VEMP waveform has been proposed to reduce the variability in vestibular evoked myogenic potentials by correcting for muscle activation. In this study, we test the hypothesis that normalization of the raw cervical VEMP waveform causes a significant decrease in the intersubject variability. Prospective cohort study. Large specialty hospital, department of otolaryngology. Twenty healthy subjects were used in this study. All subjects underwent cervical vestibular evoked myogenic potential testing using short tone bursts at 250, 500, 750, and 1,000 Hz. Both intersubject and intrasubject variability was assessed. Variability between raw and normalized peak-to-peak amplitudes was compared using the coefficient of variation. Intrasubject variability was assessed using the intraclass correlation coefficient and interaural asymmetry ratio. cVEMPs were present in most ears. Highest peak-to-peak amplitudes were recorded at 750 Hz. Normalization did not alter cVEMP tuning characteristics. Normalization of the cVEMP response caused a significant reduction in intersubject variability of the peak-to-peak amplitude. No significant change was seen in the intrasubject variability. Normalization significantly reduces cVEMP intersubject variability in healthy subjects without altering cVEMP characteristics. By reducing cVEMP amplitude variation due to nonsaccular, muscle-related factors, cVEMP normalization is expected to improve the ability to distinguish between healthy and pathologic responses in the clinical application of cVEMP testing.

Vegetative and hemodynamic responses to stress in adolescents with constitutional-exogenous obesity and vascular dystonia of hypertensive type

OpenAIRE

Larina, N.

2011-01-01

We studied the characteristics of central hemodynamics and autonomic responses to cold and psycho-emotional test in adolescents with obesity and vascular dystonia of hypertensive type. Various options for the autonomic responses accompanied by changes in central hemodynamics as a function of body weight have been identified.

Dynamics of nephron-vascular network

DEFF Research Database (Denmark)

Postnov, Dmitry; Postnov, D E; Marsh, D J

2012-01-01

The paper presents a modeling study of the spatial dynamics of a nephro-vascular network consisting of individual nephrons connected via a tree-like vascular branching structure. We focus on the effects of nonlinear mechanisms that are responsible for the formation of synchronous patterns in order...

Thermoreceptive innervation of human glabrous and hairy skin: a contact heat evoked potential analysis.

Science.gov (United States)

Granovsky, Yelena; Matre, Dagfinn; Sokolik, Alexander; Lorenz, Jürgen; Casey, Kenneth L

2005-06-01

The human palm has a lower heat detection threshold and a higher heat pain threshold than hairy skin. Neurophysiological studies of monkeys suggest that glabrous skin has fewer low threshold heat nociceptors (AMH type 2) than hairy skin. Accordingly, we used a temperature-controlled contact heat evoked potential (CHEP) stimulator to excite selectively heat receptors with C fibers or Adelta-innervated AMH type 2 receptors in humans. On the dorsal hand, 51 degrees C stimulation produced painful pinprick sensations and 41 degrees C stimuli evoked warmth. On the glabrous thenar, 41 degrees C stimulation produced mild warmth and 51 degrees C evoked strong but painless heat sensations. We used CHEP responses to estimate the conduction velocities (CV) of peripheral fibers mediating these sensations. On hairy skin, 41 degrees C stimuli evoked an ultra-late potential (mean, SD; N wave latency: 455 (118) ms) mediated by C fibers (CV by regression analysis: 1.28 m/s, N=15) whereas 51 degrees C stimuli evoked a late potential (N latency: 267 (33) ms) mediated by Adelta afferents (CV by within-subject analysis: 12.9 m/s, N=6). In contrast, thenar responses to 41 and 51 degrees C were mediated by C fibers (average N wave latencies 485 (100) and 433 (73) ms, respectively; CVs 0.95-1.35 m/s by regression analysis, N=15; average CV=1.7 (0.41) m/s calculated from distal glabrous and proximal hairy skin stimulation, N=6). The exploratory range of the human and monkey palm is enhanced by the abundance of low threshold, C-innervated heat receptors and the paucity of low threshold AMH type 2 heat nociceptors.

Sphingosine-1-Phosphate Evokes Unique Segment-Specific Vasoconstriction of the Renal Microvasculature

Science.gov (United States)

Singletary, Sean T.; Cook, Anthony K.; Hobbs, Janet L.; Pollock, Jennifer S.; Inscho, Edward W.

2014-01-01

Sphingosine-1-phosphate (S1P), a bioactive sphingolipid metabolite, has been implicated in regulating vascular tone and participating in chronic and acute kidney injury. However, little is known about the role of S1P in the renal microcirculation. Here, we directly assessed the vasoresponsiveness of preglomerular and postglomerular microvascular segments to exogenous S1P using the in vitro blood-perfused juxtamedullary nephron preparation. Superfusion of S1P (0.001–10 μM) evoked concentration-dependent vasoconstriction in preglomerular microvessels, predominantly afferent arterioles. After administration of 10 μM S1P, the diameter of afferent arterioles decreased to 35%±5% of the control diameter, whereas the diameters of interlobular and arcuate arteries declined to 50%±12% and 68%±6% of the control diameter, respectively. Notably, efferent arterioles did not respond to S1P. The S1P receptor agonists FTY720 and FTY720-phosphate and the specific S1P1 receptor agonist SEW2871 each evoked modest afferent arteriolar vasoconstriction. Conversely, S1P2 receptor inhibition with JTE-013 significantly attenuated S1P-mediated afferent arteriolar vasoconstriction. Moreover, blockade of L-type voltage-dependent calcium channels with diltiazem or nifedipine attenuated S1P-mediated vasoconstriction. Intravenous injection of S1P in anesthetized rats reduced renal blood flow dose dependently. Western blotting and immunofluorescence revealed S1P1 and S1P2 receptor expression in isolated preglomerular microvessels and microvascular smooth muscle cells. These data demonstrate that S1P evokes segmentally distinct preglomerular vasoconstriction via activation of S1P1 and/or S1P2 receptors, partially via L-type voltage-dependent calcium channels. Accordingly, S1P may have a novel function in regulating afferent arteriolar resistance under physiologic conditions. PMID:24578134

Beyond the evoked/intrinsic neural process dichotomy

Directory of Open Access Journals (Sweden)

Taylor Bolt

2018-03-01

Full Text Available Contemporary functional neuroimaging research has increasingly focused on characterization of intrinsic or “spontaneous” brain activity. Analysis of intrinsic activity is often contrasted with analysis of task-evoked activity that has traditionally been the focus of cognitive neuroscience. But does this evoked/intrinsic dichotomy adequately characterize human brain function? Based on empirical data demonstrating a close functional interdependence between intrinsic and task-evoked activity, we argue that the dichotomy between intrinsic and task-evoked activity as unobserved contributions to brain activity is artificial. We present an alternative picture of brain function in which the brain’s spatiotemporal dynamics do not consist of separable intrinsic and task-evoked components, but reflect the enaction of a system of mutual constraints to move the brain into and out of task-appropriate functional configurations. According to this alternative picture, cognitive neuroscientists are tasked with describing both the temporal trajectory of brain activity patterns across time, and the modulation of this trajectory by task states, without separating this process into intrinsic and task-evoked components. We argue that this alternative picture of brain function is best captured in a novel explanatory framework called enabling constraint. Overall, these insights call for a reconceptualization of functional brain activity, and should drive future methodological and empirical efforts.

Quantification of baseline pupillary response and task-evoked pupillary response during constant and incremental task load.

Science.gov (United States)

Mosaly, Prithima R; Mazur, Lukasz M; Marks, Lawrence B

2017-10-01

The methods employed to quantify the baseline pupil size and task-evoked pupillary response (TEPR) may affect the overall study results. To test this hypothesis, the objective of this study was to assess variability in baseline pupil size and TEPR during two basic working memory tasks: constant load of 3-letters memorisation-recall (10 trials), and incremental load memorisation-recall (two trials of each load level), using two commonly used methods (1) change from trail/load specific baseline, (2) change from constant baseline. Results indicated that there was a significant shift in baseline between the trails for constant load, and between the load levels for incremental load. The TEPR was independent of shifts in baseline using method 1 only for constant load, and method 2 only for higher levels of incremental load condition. These important findings suggest that the assessment of both the baseline and methods to quantify TEPR are critical in ergonomics application, especially in studies with small number of trials per subject per condition. Practitioner Summary: Quantification of TEPR can be affected by shifts in baseline pupil size that are most likely affected by non-cognitive factors when other external factors are kept constant. Therefore, quantification methods employed to compute both baseline and TEPR are critical in understanding the information processing of humans in practical ergonomics settings.

Task-evoked brain functional magnetic susceptibility mapping by independent component analysis (χICA).

Science.gov (United States)

Chen, Zikuan; Calhoun, Vince D

2016-03-01

Conventionally, independent component analysis (ICA) is performed on an fMRI magnitude dataset to analyze brain functional mapping (AICA). By solving the inverse problem of fMRI, we can reconstruct the brain magnetic susceptibility (χ) functional states. Upon the reconstructed χ dataspace, we propose an ICA-based brain functional χ mapping method (χICA) to extract task-evoked brain functional map. A complex division algorithm is applied to a timeseries of fMRI phase images to extract temporal phase changes (relative to an OFF-state snapshot). A computed inverse MRI (CIMRI) model is used to reconstruct a 4D brain χ response dataset. χICA is implemented by applying a spatial InfoMax ICA algorithm to the reconstructed 4D χ dataspace. With finger-tapping experiments on a 7T system, the χICA-extracted χ-depicted functional map is similar to the SPM-inferred functional χ map by a spatial correlation of 0.67 ± 0.05. In comparison, the AICA-extracted magnitude-depicted map is correlated with the SPM magnitude map by 0.81 ± 0.05. The understanding of the inferiority of χICA to AICA for task-evoked functional map is an ongoing research topic. For task-evoked brain functional mapping, we compare the data-driven ICA method with the task-correlated SPM method. In particular, we compare χICA with AICA for extracting task-correlated timecourses and functional maps. χICA can extract a χ-depicted task-evoked brain functional map from a reconstructed χ dataspace without the knowledge about brain hemodynamic responses. The χICA-extracted brain functional χ map reveals a bidirectional BOLD response pattern that is unavailable (or different) from AICA. Copyright © 2016 Elsevier B.V. All rights reserved.

Erythroxylum pungens elicits vasorelaxation by reducing intracellular calcium concentration in vascular smooth muscle cells of rats

Directory of Open Access Journals (Sweden)

Aurylene C. Oliveira

2012-01-01

Full Text Available The cardiovascular effects elicited by the ethanolic extract obtained from the roots of Erythroxylum pungens O.E. Schulz, Erythroxylaceae (EEEP and the vasorelaxant effect induced by its main tropane alkaloid (pungencine were investigated. In normotensive rats, administration of EEEP (1, 10, 30 and 60 mg/kg i.v., randomly produced dose-dependent hypotension (-2±1, -7±0.5 -17.6±1, -24±1 Δ mmHg, n=5 followed by tachycardia (3±0.5, 7±2, 7.1±1, 10±5 Δ bpm, n=5. In intact phenylephrine (Phe, 10 µM-pre-contracted rings, EEEP (0.01-500 µg/mL induced concentration-dependent vasorelaxation (EC50 13.7±5.5 µg/mL, Maximal Response= 92±2.6%, and this effect was unchanged after the removal of the vascular endothelium (EC50 27.2±4.7 µg/ml, Maximal Response= 88.3±3.3 %. In KCl (80 mM-pre-contracted-endothelium-denuded rings, EEEP elicited concentration-dependent relaxation (EC50= 128.2±11.2 µg/mL, Maximal Response 76.8±3.4%. Vasorelaxation has also been achieved with tonic contractions evoked by the L-type Ca2+ channel agonist Bay K 8644 (EC50 80.2±9.1 µg/mL, Maximal Response 86.3±8.3%. In addition, in a depolarizing medium, EEEP inhibited CaCl2 (30-500 µg/mL induced contractions and caused a concentration-dependent rightward shift of the relaxation curves. Lastly, the tropane alkaloid pungencine caused vasorelaxation in mesenteric arteries resembling to the EEEP responses. These results suggests that EEEP induces hypotension and vasorelaxation, at least in part, due to the reduction in [Ca2+]i in vascular smooth muscle cells.

Music-evoked emotions in schizophrenia.

Science.gov (United States)

Abe, Daijyu; Arai, Makoto; Itokawa, Masanari

2017-07-01

Previous studies have reported that people with schizophrenia have impaired musical abilities. Here we developed a simple music-based assay to assess patient's ability to associate a minor chord with sadness. We further characterize correlations between impaired musical responses and psychiatric symptoms. We exposed participants sequentially to two sets of sound stimuli, first a C-major progression and chord, and second a C-minor progression and chord. Participants were asked which stimulus they associated with sadness, the first set, the second set, or neither. The severity of psychiatric symptoms was assessed using the Positive and Negative Syndrome Scale (PANSS). Study participants were 29 patients diagnosed with schizophrenia and 29 healthy volunteers matched in age, gender and musical background. 37.9% (95% confidence interval [CI]:19.1-56.7) of patients with schizophrenia associated the minor chord set as sad, compared with 97.9% (95%CI: 89.5-103.6) of controls. Four patients were diagnosed with treatment-resistant schizophrenia, and all four failed to associate the minor chord with sadness. Patients who did not recognize minor chords as sad had significantly higher scores on all PANSS subscales. A simple test allows music-evoked emotions to be assessed in schizophrenia patient, and may show potential relationships between music-evoked emotions and psychiatric symptoms. Copyright © 2016. Published by Elsevier B.V.

Circulatory response evoked by a 3 s bout of dynamic leg exercise in humans

NARCIS (Netherlands)

Wieling, W.; Harms, M. P.; ten Harkel, A. D.; van Lieshout, J. J.; Sprangers, R. L.

1996-01-01

1. The mechanisms underlying the pronounced transient fall in arterial blood pressure evoked by a 3 s bout of bicycle exercise were investigated in twenty healthy young adults and four patients with hypoadrenergic orthostatic hypotension. 2. In healthy subjects a 3 s bout of upright cycling induced

 Evaluation of the humoral and cellular immune responses after implantation of a PTFE vascular prosthesis.

Science.gov (United States)

Skóra, Jan; Pupka, Artur; Dorobisz, Andrzej; Barć, Piotr; Korta, Krzysztof; Dawiskiba, Tomasz

2012-07-02

The experiment was designed in order to determine the immunological processes that occur during the healing in synthetic vascular grafts, especially to establish the differences in the location of the complement system proteins between the proximal and distal anastomosis and the differences in the arrangement of inflammatory cells in those anastomoses. The understanding of those processes will provide a true basis for determining risk factors for complications after arterial repair procedures. The experiment was carried out on 16 dogs that underwent implantation of unilateral aorto-femoral bypass with expanded polytetrafluoroethylene (ePTFE). After 6 months all animals were euthanized to dissect the vascular grafts. Immunohistochemical assays and electron microscopic examinations were performed. Immunohistochemical findings in the structure of neointima between anastomoses of vascular prostheses demonstrated significant differences between humoral and cellular responses. The area of proximal anastomosis revealed the presence of fibroblasts, but no macrophages were detected. The histological structure of the proximal anastomosis indicates that inflammatory processes were ended during the prosthesis healing. The immunological response obtained in the distal anastomosis corresponded to the chronic inflammatory reaction with the presence of macrophages, myofibroblasts and deposits of complement C3. The identification of differences in the presence of macrophages and myofibroblasts and the presence of the C3 component between the anastomoses is the original achievement of the present study. In the available literature, no such significant differences have been shown so far in the humoral and cellular immune response caused by the presence of an artificial vessel in the arterial system.

Vascular retraction driven by matrix softening

Science.gov (United States)

Valentine, Megan

We recently discovered we can directly apply physical forces and monitor the downstream responses in a living organism in real time through manipulation of the blood vessels of a marine organism called, Botryllus schlosseri. The extracellular matrix (ECM) plays a key role in regulating vascular growth and homeostasis in Botryllus,a basal chordate which has a large, transparent extracorporeal vascular network that can encompass areas >100 cm2. We have determined that lysyl oxidase 1 (LOX1), which is responsible for cross-linking collagen, is expressed in all vascular cells and is critically important for vascular maintenance. Inhibition of LOX1 activity in vivo by the addition of a specific inhibitor, ß-aminopropionitrile (BAPN), caused a rapid, global regression of the entire vascular bed, with some vessels regressing >10 mm within 16 hrs. In this talk, I will discuss the molecular and cellular origins of this systemic remodeling event, which hinges upon the ability of the vascular cells to sense and respond to mechanical signals, while introducing this exciting new model system for studies of biological physics and mechanobiology. Collaborators: Anthony DeTomaso, Delany Rodriguez, Aimal Khankhel (UCSB).

Repetitive muscle compression reduces vascular mechano-sensitivity and the hyperemic response to muscle contraction.

Science.gov (United States)

Messere, A; Turturici, M; Millo, G; Roatta, S

2017-06-01

Animal studies have shown that the rapid hyperemic response to external muscle compression undergoes inactivation upon repetitive stimulation, but this phenomenon has never been observed in humans. The aim of the present study was to determine whether 1) the vascular mechano-sensitivity underlying muscle compression-induced hyperemia is inactivated in an inter-stimulus interval (ISI)-dependent fashion upon repetitive stimulation, as suggested by animal studies, and 2) whether such inactivation also attenuates contraction-induced hyperemia. Brachial artery blood flow was measured by echo Doppler sonography in 13 healthy adults in response to 1) single and repetitive cuff muscle compression (CMC) of the forearm (20 CMCs, 1 s ISI); 2) a sequence of CMC delivered at decreasing ISI from 120 to 2 s; and 3) electrically-stimulated contraction of the forearm muscles before and after repetitive CMC. The peak amplitude of hyperemia in response to CMC normalized to baseline decreased from 2.2 ± 0.6 to 1.4 ± 0.4 after repetitive CMC and, in general, was decreased at ISI < 240 s. The peak amplitude of contraction-induced hyperemia was attenuated after as compared to before repeated CMC (1.7 ± 0.4 and 2.6 ± 0.6, respectively). Mechano-sensitivity of the vascular network can be conditioned by previous mechanical stimulation, and such preconditioning may substantially decrease contraction-induced hyperemia.

Response of local vascular volumes to lower body negative pressure stress

Science.gov (United States)

Wolthuis, R. A.; Leblanc, A.; Carpentier, W. A.; Bergman, S. A., Jr.

1975-01-01

The present study involved an intravenous injection of radioactive iodinated serum albumin, equilibration of this isotope within the vascular space, and the continuous measurement of isotope activity over selected anatomical areas before, during and following multiple human LBNP tests. Both rate and magnitude of vascular pooling were distinctly different within each of five selected lower body anatomical areas. In the upper body, all areas except the abdomen showed depletions from their resting vascular volumes during LBNP. The presence of uniquely different pooling patterns in the lower body, the apparent stability of abdominal vascular volumes, and a possible decrease in cerebral blood volume during LBNP represent the major findings of this study.

Normalization of auditory evoked potential and visual evoked potential in patients with idiot savant.

Science.gov (United States)

Chen, X; Zhang, M; Wang, J; Lou, F; Liang, J

1999-03-01

To investigate the variations of auditory evoked potentials (AEP) and visual evoked potentials (VEP) of patients with idiot savant (IS) syndrome. Both AEP and VEP were recorded from 7 patients with IS syndrome, 21 mentally retarded (MR) children without the syndrome and 21 normally age-matched controls, using a Dantec concerto SEEG-16 BEAM instrument. Both AEP and VEP of MR group showed significantly longer latencies (P1 and P2 latencies of AEP, P savant syndrome presented normalized AEP and VEP.

Central amygdalar nucleus treated with orexin neuropeptides evoke differing feeding and grooming responses in the hamster.

Science.gov (United States)

Alò, Raffaella; Avolio, Ennio; Mele, Maria; Di Vito, Anna; Canonaco, Marcello

2015-04-15

Interaction of the orexinergic (ORXergic) neuronal system with the excitatory (glutamate, l-Glu) or the inhibitory (GABA) neurosignaling complexes evokes major homeostatic physiological events. In this study, effects of the two ORXergic neuropeptides (ORX-A/B) on their receptor (ORX-2R) expression changes were correlated to feeding and grooming actions of the hibernating hamster (Mesocricetus auratus). Infusion of the central amygdala nucleus (CeA) with ORX-A caused hamsters to consume notable quantities of food, while ORX-B accounted for a moderate increase. Interestingly the latter neuropeptide was responsible for greater frequencies of grooming with respect to both controls and the hamsters treated with ORX-A. These distinct behavioral changes turned out to be even greater in the presence of l-Glu agonist (NMDA) while the α1 GABAA receptor agonist (zolpidem, Zol) greatly reduced ORX-A-dependent feeding bouts. Moreover, ORX-A+NMDA mainly promoted greater ORX-2R expression levels with respect to ORX-A-treated hamsters while ORX-B+Zol was instead largely responsible for a down-regulatory trend. Overall, these features point to CeA ORX-2R sites as key sensory limbic elements capable of regulating eating and grooming responses, which may provide useful insights regarding the type of molecular mechanism(s) operating during feeding bouts. Copyright © 2015 Elsevier B.V. All rights reserved.

Visually Evoked Spiking Evolves While Spontaneous Ongoing Dynamics Persist

Science.gov (United States)

Huys, Raoul; Jirsa, Viktor K.; Darokhan, Ziauddin; Valentiniene, Sonata; Roland, Per E.

2016-01-01

Neurons in the primary visual cortex spontaneously spike even when there are no visual stimuli. It is unknown whether the spiking evoked by visual stimuli is just a modification of the spontaneous ongoing cortical spiking dynamics or whether the spontaneous spiking state disappears and is replaced by evoked spiking. This study of laminar recordings of spontaneous spiking and visually evoked spiking of neurons in the ferret primary visual cortex shows that the spiking dynamics does not change: the spontaneous spiking as well as evoked spiking is controlled by a stable and persisting fixed point attractor. Its existence guarantees that evoked spiking return to the spontaneous state. However, the spontaneous ongoing spiking state and the visual evoked spiking states are qualitatively different and are separated by a threshold (separatrix). The functional advantage of this organization is that it avoids the need for a system reorganization following visual stimulation, and impedes the transition of spontaneous spiking to evoked spiking and the propagation of spontaneous spiking from layer 4 to layers 2–3. PMID:26778982

WE-FG-202-02: Exploration of High-Resolution Quantitative Ultrasonic Micro-Vascular Imaging for Early Assessment of Radiotherapy Tumor Response

Energy Technology Data Exchange (ETDEWEB)

Kasoji, S; Rivera, J; Dayton, P [University of North Carolina- Chapel Hill/ North Carolina State University, Chapel Hill, NC (United States); Buse, J [UNC School of Medicine, Chapel Hill, NC (United States); Chang, S [University of North Carolina- Chapel Hill/ North Carolina State University, Chapel Hill, NC (United States); UNC School of Medicine, Chapel Hill, NC (United States)

2016-06-15

Purpose: Currently, we cannot predict an individual patient’s response to a given radiotherapy which normally is not detected for weeks to months post-treatment. As a result, precious time is wasted for patients with unresponsive tumors who could have switched to an alternative treatment much earlier. Presently, no early treatment response detection method exists that is effective, low-cost, non-invasive, and safe. We hypothesize that changes in tumor microvasculature predict tumor response to radiotherapy earlier than tumor volume changes. Recent radiobiology research suggests tumors undergo vascular remodeling in response to radiation well before manifesting changes in tumor volume. We propose monitoring tumor microvasculature post-radiation using Acoustic Angiography (AA), a novel ultrasound imaging modality developed and patented in-house. In this study, we investigate whether changes in tumor microvasculature, measured using AA, can be an early indicator of high-dose radiotherapy success, compared to changes in tumor volume. Methods: Fibrosarcoma xenograft tumor tissue was subcutaneously implanted into rodent flanks (N=10). Animal tumors (N=8) were irradiated with a single treatment of 15Gy using a clinical LINAC at 100SSD and 2×2cm field size. Two untreated rats were left as tumor controls. AA imaging was performed immediately posttreatment and every third day thereafter for 30 days, or until tumors disappeared. Tumor volumes and vascular densities were measured from anatomical b-mode ultrasound and AA images, respectively. Results: Statistical differences in vascular density between treatment responders and non-responders were observed on Day 10 (p=0.005), whereas statistical differences in tumor volume were not observed until Day 19 (p=0.02). Conclusions: Tumor vascularity differences may be observed substantially earlier than differences in tumor size. In addition, significant early increases in vascular density were observed in non-responding tumors

Broad-Band Visually Evoked Potentials: Re(convolution in Brain-Computer Interfacing.

Directory of Open Access Journals (Sweden)

Jordy Thielen

Full Text Available Brain-Computer Interfaces (BCIs allow users to control devices and communicate by using brain activity only. BCIs based on broad-band visual stimulation can outperform BCIs using other stimulation paradigms. Visual stimulation with pseudo-random bit-sequences evokes specific Broad-Band Visually Evoked Potentials (BBVEPs that can be reliably used in BCI for high-speed communication in speller applications. In this study, we report a novel paradigm for a BBVEP-based BCI that utilizes a generative framework to predict responses to broad-band stimulation sequences. In this study we designed a BBVEP-based BCI using modulated Gold codes to mark cells in a visual speller BCI. We defined a linear generative model that decomposes full responses into overlapping single-flash responses. These single-flash responses are used to predict responses to novel stimulation sequences, which in turn serve as templates for classification. The linear generative model explains on average 50% and up to 66% of the variance of responses to both seen and unseen sequences. In an online experiment, 12 participants tested a 6 × 6 matrix speller BCI. On average, an online accuracy of 86% was reached with trial lengths of 3.21 seconds. This corresponds to an Information Transfer Rate of 48 bits per minute (approximately 9 symbols per minute. This study indicates the potential to model and predict responses to broad-band stimulation. These predicted responses are proven to be well-suited as templates for a BBVEP-based BCI, thereby enabling communication and control by brain activity only.

A Parallel World for the World Bank: A Case Study of Urgent: Evoke, An Educational Alternate Reality Game

Directory of Open Access Journals (Sweden)

David I. Waddington

2013-01-01

Full Text Available In 2010, the World Bank launched Urgent: Evoke, an alternate reality game. Conceived in response to the demands of African universities, the game was designed to promote the World Bank Institute’s vision of positive global change through social innovation, and made substantial use of Web 2.0 tools such as blogs, personal profiles, and social networks. This article offers a case study of Urgent: Evoke, divided into four sections: first, the potential to use video games as citizenship education tools is discussed; second, the unique game genre (alternate reality games into which Evoke falls is explained and some possible uses of this genre in higher education are examined; third, the functioning of the Evoke game world is explained; and fourth, the results of the Evoke educational project are assessed. The case study concludes with some commentary on Evoke’s ideological message, which those less sympathetic to capitalism may view as problematic.

Pulmonary vascular responses during acute and sustained respiratory alkalosis or acidosis in intact newborn piglets.

Science.gov (United States)

Gordon, J B; Rehorst-Paea, L A; Hoffman, G M; Nelin, L D

1999-12-01

Acute alkalosis-induced pulmonary vasodilation and acidosis-induced pulmonary vasoconstriction have been well described, but responses were generally measured within 5-30 min of changing pH. In contrast, several in vitro studies have found that relatively brief periods of sustained alkalosis can enhance, and sustained acidosis can decrease, vascular reactivity. In this study of intact newborn piglets, effects of acute (20 min) and sustained (60-80 min) alkalosis or acidosis on baseline (35% O2) and hypoxic (12% O2) pulmonary vascular resistance (PVR) were compared with control piglets exposed only to eucapnia. Acute alkalosis decreased hypoxic PVR, but sustained alkalosis failed to attenuate either baseline PVR or the subsequent hypoxic response. Acute acidosis did not significantly increase hypoxic PVR, but sustained acidosis markedly increased both baseline PVR and the subsequent hypoxic response. Baseline PVR was similar in all piglets after resumption of eucapnic ventilation, but the final hypoxic response was greater in piglets previously exposed to alkalosis than in controls. Thus, hypoxic pulmonary vasoconstriction was not attenuated during sustained alkalosis, but was accentuated during sustained acidosis and after the resumption of eucapnia in alkalosis-treated piglets. Although extrapolation of data from normal piglets to infants and children with pulmonary hypertension must be done with caution, this study suggests that sustained alkalosis may be of limited efficacy in treating acute hypoxia-induced pulmonary hypertension and the risks of pulmonary hypertension must be considered when using ventilator strategies resulting in permissive hypercapnic acidosis.

Proprioceptive evoked potentials in man: cerebral responses to changing weight loads on the hand

DEFF Research Database (Denmark)

Arnfred, S; He, Chen; Eder, D

2000-01-01

We studied cerebral evoked potentials on the scalp to the stimulation of the right hand from a change in weight of 400-480 g in ten subjects. Rise-time was 20g/10 ms, Inter Stimulus Interval 2s and stimulus duration was 100 ms. The cerebral activations were a double positive contralateral C3'/P70...

Influence of myocardial oxygen demand on the coronary vascular response to arterial blood gas changes in humans.

Science.gov (United States)

Vermeulen, Tyler Dennis; Boulet, Lindsey M; Stembridge, Mike; Williams, Alexandra Mackenzie; Anholm, James D; Subedi, Prajan; Gasho, Chris; Ainslie, Philip N; Feigl, Eric O; Foster, Glen Edward

2018-03-30

It remains unclear if the human coronary vasculature is inherently sensitive to changes in arterial PO 2 and PCO 2 or if coronary vascular responses are the result of concomitant increases in myocardial O 2 consumption/demand (MVO 2 ). We hypothesized that the coronary vascular response to PO 2 and PCO 2 would be attenuated in healthy men when MVO 2 was attenuated with β 1 -adrenergic receptor blockade. Healthy men (n=11; age: 25 {plus minus} 1 years) received intravenous esmolol (β 1 -adrenergic receptor antagonist) or volume-matched saline in a double-blind, randomized, crossover study, and were exposed to poikilocapnic hypoxia, isocapnic hypoxia, and hypercapnic hypoxia. Measurements made at baseline and following 5-min of steady state at each gas manipulation included left anterior descending coronary blood velocity (LAD V ; Doppler echocardiography), heart rate and arterial blood pressure. LAD V values at the end of each hypoxic condition were compared between esmolol and placebo. Rate pressure product (RPP) and left-ventricular mechanical energy (ME LV ) were calculated as indices of MVO 2 . All gas manipulations augmented RPP, ME LV , and LAD V but only RPP and ME LV were attenuated (4-18%) following β 1 -adrenergic receptor blockade (P<0.05). Despite attenuated RPP and MELV responses, β 1 -adrenergic receptor blockade did not attenuate the mean LADV vasodilatory response when compared to placebo during poikilocapnic hypoxia (29.4{plus minus}2.2 vs. 27.3{plus minus}1.6 cm/s) and isocapnic hypoxia (29.5{plus minus}1.5 vs. 30.3{plus minus}2.2 cm/s). Hypercapnic hypoxia elicited a feed-forward coronary dilation that was blocked by β 1 -adrenergic receptor blockade. These results indicate a direct influence of arterial PO 2 on coronary vascular regulation that is independent of MVO 2 .

Time-varying bispectral analysis of visually evoked multi-channel EEG

Science.gov (United States)

Chandran, Vinod

2012-12-01

Theoretical foundations of higher order spectral analysis are revisited to examine the use of time-varying bicoherence on non-stationary signals using a classical short-time Fourier approach. A methodology is developed to apply this to evoked EEG responses where a stimulus-locked time reference is available. Short-time windowed ensembles of the response at the same offset from the reference are considered as ergodic cyclostationary processes within a non-stationary random process. Bicoherence can be estimated reliably with known levels at which it is significantly different from zero and can be tracked as a function of offset from the stimulus. When this methodology is applied to multi-channel EEG, it is possible to obtain information about phase synchronization at different regions of the brain as the neural response develops. The methodology is applied to analyze evoked EEG response to flash visual stimulii to the left and right eye separately. The EEG electrode array is segmented based on bicoherence evolution with time using the mean absolute difference as a measure of dissimilarity. Segment maps confirm the importance of the occipital region in visual processing and demonstrate a link between the frontal and occipital regions during the response. Maps are constructed using bicoherence at bifrequencies that include the alpha band frequency of 8Hz as well as 4 and 20Hz. Differences are observed between responses from the left eye and the right eye, and also between subjects. The methodology shows potential as a neurological functional imaging technique that can be further developed for diagnosis and monitoring using scalp EEG which is less invasive and less expensive than magnetic resonance imaging.

Lateralization and Binaural Interaction of Middle-Latency and Late-Brainstem Components of the Auditory Evoked Response.

Science.gov (United States)

Dykstra, Andrew R; Burchard, Daniel; Starzynski, Christian; Riedel, Helmut; Rupp, Andre; Gutschalk, Alexander

2016-08-01

We used magnetoencephalography to examine lateralization and binaural interaction of the middle-latency and late-brainstem components of the auditory evoked response (the MLR and SN10, respectively). Click stimuli were presented either monaurally, or binaurally with left- or right-leading interaural time differences (ITDs). While early MLR components, including the N19 and P30, were larger for monaural stimuli presented contralaterally (by approximately 30 and 36 % in the left and right hemispheres, respectively), later components, including the N40 and P50, were larger ipsilaterally. In contrast, MLRs elicited by binaural clicks with left- or right-leading ITDs did not differ. Depending on filter settings, weak binaural interaction could be observed as early as the P13 but was clearly much larger for later components, beginning at the P30, indicating some degree of binaural linearity up to early stages of cortical processing. The SN10, an obscure late-brainstem component, was observed consistently in individuals and showed linear binaural additivity. The results indicate that while the MLR is lateralized in response to monaural stimuli-and not ITDs-this lateralization reverses from primarily contralateral to primarily ipsilateral as early as 40 ms post stimulus and is never as large as that seen with fMRI.

Genetic Regulation of Vascular Development: Building the Zebrafish Vascular Tree

NARCIS (Netherlands)

R.L.J.M. Herpers (Robert)

2010-01-01

textabstractThe extensive networks of blood and lymphatic vessels within the vertebrate body are essential for the transport and delivery of fluids, gases, macromolecules and cells, and play important roles in facilitating immune responses. The development of the vascular tree requires a highly

Skin-transmitted pathogens and the heebie jeebies: evidence for a subclass of disgust stimuli that evoke a qualitatively unique emotional response.

Science.gov (United States)

Blake, Khandis R; Yih, Jennifer; Zhao, Kun; Sung, Billy; Harmon-Jones, Cindy

2017-09-01

Skin-transmitted pathogens have threatened humans since ancient times. We investigated whether skin-transmitted pathogens were a subclass of disgust stimuli that evoked an emotional response that was related to, but distinct from, disgust and fear. We labelled this response "the heebie jeebies". In Study 1, coding of 76 participants' experiences of disgust, fear, and the heebie jeebies showed that the heebie jeebies was elicited by unique stimuli which produced skin-crawling sensations and an urge to protect the skin. In Experiment 2,350 participants' responses to skin-transmitted pathogen, fear-inducing, and disgust-inducing vignettes showed that the vignettes elicited sensations and urges which loaded onto heebie jeebies, fear, and disgust factors, respectively. Experiment 3 largely replicated findings from Experiment 2 using video stimuli (178 participants). Results are consistent with the notion that skin-transmitted pathogens are a subclass of disgust stimuli which motivate behaviours that are functionally consistent with disgust yet qualitatively distinct.

Effect of mechanical tactile noise on amplitude of visual evoked potentials: multisensory stochastic resonance.

Science.gov (United States)

Méndez-Balbuena, Ignacio; Huidobro, Nayeli; Silva, Mayte; Flores, Amira; Trenado, Carlos; Quintanar, Luis; Arias-Carrión, Oscar; Kristeva, Rumyana; Manjarrez, Elias

2015-10-01

The present investigation documents the electrophysiological occurrence of multisensory stochastic resonance in the human visual pathway elicited by tactile noise. We define multisensory stochastic resonance of brain evoked potentials as the phenomenon in which an intermediate level of input noise of one sensory modality enhances the brain evoked response of another sensory modality. Here we examined this phenomenon in visual evoked potentials (VEPs) modulated by the addition of tactile noise. Specifically, we examined whether a particular level of mechanical Gaussian noise applied to the index finger can improve the amplitude of the VEP. We compared the amplitude of the positive P100 VEP component between zero noise (ZN), optimal noise (ON), and high mechanical noise (HN). The data disclosed an inverted U-like graph for all the subjects, thus demonstrating the occurrence of a multisensory stochastic resonance in the P100 VEP. Copyright © 2015 the American Physiological Society.

Estrogen, vascular estrogen receptor and hormone therapy in postmenopausal vascular disease.

Science.gov (United States)

Khalil, Raouf A

2013-12-15

Cardiovascular disease (CVD) is less common in premenopausal women than men of the same age or postmenopausal women, suggesting vascular benefits of estrogen. Estrogen activates estrogen receptors ERα, ERβ and GPR30 in endothelium and vascular smooth muscle (VSM), which trigger downstream signaling pathways and lead to genomic and non-genomic vascular effects such as vasodilation, decreased VSM contraction and growth and reduced vascular remodeling. However, randomized clinical trials (RCTs), such as the Women's Health Initiative (WHI) and Heart and Estrogen/progestin Replacement Study (HERS), have shown little vascular benefits and even adverse events with menopausal hormone therapy (MHT), likely due to factors related to the MHT used, ER profile, and RCT design. Some MHT forms, dose, combinations or route of administration may have inadequate vascular effects. Age-related changes in ER amount, distribution, integrity and post-ER signaling could alter the vascular response to MHT. The subject's age, preexisting CVD, and hormone environment could also reduce the effects of MHT. Further evaluation of natural and synthetic estrogens, phytoestrogens, and selective estrogen-receptor modulators (SERMs), and the design of appropriate MHT combinations, dose, route and 'timing' could improve the effectiveness of conventional MHT and provide alternative therapies in the peri-menopausal period. Targeting ER using specific ER agonists, localized MHT delivery, and activation of specific post-ER signaling pathways could counter age-related changes in ER. Examination of the hormone environment and conditions associated with hormone imbalance such as polycystic ovary syndrome may reveal the causes of abnormal hormone-receptor interactions. Consideration of these factors in new RCTs such as the Kronos Early Estrogen Prevention Study (KEEPS) could enhance the vascular benefits of estrogen in postmenopausal CVD. Copyright © 2013 Elsevier Inc. All rights reserved.

Aminolevulinic acid-photodynamic therapy combined with topically applied vascular disrupting agent vadimezan leads to enhanced antitumor responses.

Science.gov (United States)

Marrero, Allison; Becker, Theresa; Sunar, Ulas; Morgan, Janet; Bellnier, David

2011-01-01

The tumor vascular-disrupting agent (VDA) vadimezan (5,6-dimethylxanthenone-4-acetic acid, DMXAA) has been shown to potentiate the antitumor activity of photodynamic therapy (PDT) using systemically administered photosensitizers. Here, we characterized the response of subcutaneous syngeneic Colon26 murine colon adenocarcinoma tumors to PDT using the locally applied photosensitizer precursor aminolevulinic acid (ALA) in combination with a topical formulation of vadimezan. Diffuse correlation spectroscopy (DCS), a noninvasive method for monitoring blood flow, was utilized to determine tumor vascular response to treatment. In addition, correlative CD31-immunohistochemistry to visualize endothelial damage, ELISA to measure induction of tumor necrosis factor-alpha (TNF-α) and tumor weight measurements were also examined in separate animals. In our previous work, DCS revealed a selective decrease in tumor blood flow over time following topical vadimezan. ALA-PDT treatment also induced a decrease in tumor blood flow. The onset of blood flow reduction was rapid in tumors treated with both ALA-PDT and vadimezan. CD31-immunostaining of tumor sections confirmed vascular damage following topical application of vadimezan. Tumor weight measurements revealed enhanced tumor growth inhibition with combination treatment compared with ALA-PDT or vadimezan treatment alone. In conclusion, vadimezan as a topical agent enhances treatment efficacy when combined with ALA-PDT. This combination could be useful in clinical applications. © 2011 The Authors. Photochemistry and Photobiology © 2011 The American Society of Photobiology.

Towards a neural basis of music-evoked emotions.

Science.gov (United States)

Koelsch, Stefan

2010-03-01

Music is capable of evoking exceptionally strong emotions and of reliably affecting the mood of individuals. Functional neuroimaging and lesion studies show that music-evoked emotions can modulate activity in virtually all limbic and paralimbic brain structures. These structures are crucially involved in the initiation, generation, detection, maintenance, regulation and termination of emotions that have survival value for the individual and the species. Therefore, at least some music-evoked emotions involve the very core of evolutionarily adaptive neuroaffective mechanisms. Because dysfunctions in these structures are related to emotional disorders, a better understanding of music-evoked emotions and their neural correlates can lead to a more systematic and effective use of music in therapy. Copyright 2010 Elsevier Ltd. All rights reserved.

The vascular surgery workforce: a survey of consultant vascular surgeons in the UK, 2014.

Science.gov (United States)

Harkin, D W; Beard, J D; Shearman, C P; Wyatt, M G

2015-04-01

The purpose of this study was to describe the demographics, training, and practice characteristics of consultant vascular surgeons across the UK to provide an assessment of current, and inform future prediction of workforce needs. A questionnaire was developed using a modified Delphi process to generate questionnaire items. The questionnaire was emailed to all consultant vascular surgeons (n = 450) in the UK who were members of the Vascular Society of Great Britain & Ireland. 352 consultant vascular surgeons from 95 hospital trusts across the UK completed the survey (78% response rate). The mean age was 50.6 years old, the majority (62%) were mid-career, but 24% were above the age of 55. Currently, 92% are men and only 8% women. 93% work full-time, with 60% working >50 hours, and 21% working >60 hours per week. The average team was 5 to 6 (range 2-10) vascular surgeons, with 23% working in a large team of ≥8. 17% still work in small teams of ≤3. Over 90% of consultant vascular surgeons perform the major index vascular surgery procedures (aneurysm repair, carotid endarterectomy, infra-inguinal bypass, amputation). While 84% perform standard endovascular abdominal aortic aneurysm repair (EVAR), <50% perform more complex endovascular aortic therapy. The majority of vascular surgeons "like their job" (85%) and are "satisfied" (69%) with their job. 34% of consultant vascular surgeons indicated they were "extremely likely" to retire within the next 10 years. This study provides the first detailed analysis of the new specialty of vascular surgery as practiced in the UK. There is a need to plan for a significant expansion in the consultant vascular surgeon workforce in the UK over the next 10 years to maintain the status quo. Copyright © 2014 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Developmental Changes in Sensory-Evoked Optical Intrinsic Signals in the Rat Barrel Cortex

Directory of Open Access Journals (Sweden)

Mikhail Sintsov

2017-12-01

Full Text Available Optical Intrinsic Signal imaging (OISi is a powerful technique for optical brain studies. OIS mainly reflects the hemodynamic response (HR and metabolism, but it may also involve changes in tissue light scattering (LS caused by transient cellular swelling in the active tissue. Here, we explored the developmental features of sensory-evoked OIS in the rat barrel cortex during the first 3 months after birth. Multispectral OISi revealed that two temporally distinct components contribute to the neonatal OIS: an early phase of LS followed by a late phase of HR. The contribution of LS to the early response was also evidenced by an increase in light transmission through the active barrel. The early OIS phase correlated in time and amplitude with the sensory-evoked electrophysiological response. Application of the Modified Beer-Lambert Law (MBLL to the OIS data revealed that HR during the early phase involved only a slight decrease in blood oxygenation without any change in blood volume. In contrast, HR during the late phase manifested an adult-like increase in blood volume and oxygenation. During development, the peak time of the delayed HR progressively shortened with age, nearly reaching the stimulus onset and overlapping with the early LS phase by the fourth postnatal week. Thus, LS contributes to the sensory-evoked OIS in the barrel cortex of rats at all ages, and it dominates the early OIS phase in neonatal rats due to delayed HR. Our results are also consistent with the delayed blood oxygen level dependent (BOLD signal in human preterm infants.

Associative learning in humans--conditioning of sensory-evoked brain activity.

Science.gov (United States)

Skrandies, W; Jedynak, A

2000-01-01

A classical conditioning paradigm was employed in two experiments performed on 35 human volunteers. In nine subjects, the presentation of Landolt rings (conditioned stimuli, CS + ) was paired with an electric stimulus (unconditioned stimuli, UCS) applied to the left median nerve. Neutral visual control stimuli were full circles (CS -) that were not paired with the UCS. The skin conductance response (SCR) was determined in a time interval of 5 s after onset of the visual stimuli, and it was measured in the acquisition and test phase. Associative learning was reflected by a SCR occurring selectively with CS +. The same experiment was repeated with another group of 26 adults while electroencephalogram (EEG) was recorded from 30 electrodes. For each subject, mean evoked potentials were computed. In 13 of the subjects, a conditioning paradigm was followed while the other subjects served as the control group (non-contingent stimulation). There were somatosensory and visual brain activity evoked by the stimuli. Conditioned components were identified by computing cross-correlation between evoked somatosensory components and the averaged EEG. In the visual evoked brain activity, three components with mean latencies of 105.4, 183.2, and 360.3 ms were analyzed. Somatosensory stimuli were followed by major components that occurred at mean latencies of 48.8, 132.5, 219.7, 294.8, and 374.2 ms latency after the shock. All components were analyzed in terms of latency, field strength, and topographic characteristics, and were compared between groups and experimental conditions. Both visual and somatosensory brain activity was significantly affected by classical conditioning. Our data illustrate how associative learning affects the topography of brain electrical activity elicited by presentation of conditioned visual stimuli.

Resveratrol prevents angiotensin II-induced hypertrophy of vascular smooth muscle cells through the transactivation of growth factor receptors.

Science.gov (United States)

Hossain, Ekhtear; Anand-Srivastava, Madhu B

2017-08-01

We previously showed that augmented levels of endogenous angiotensin II (AngII) contribute to vascular smooth muscle cell (VSMC) hypertrophy through the transactivation of growth factor receptors in spontaneously hypertensive rats. Resveratrol (RV), a polyphenolic component of red wine, has also been shown to attenuate AngII-evoked VSMC hypertrophy; however, the molecular mechanism mediating this response is obscure. The present study was therefore undertaken to examine whether RV could prevent AngII-induced VSMC hypertrophy through the transactivation of growth factor receptor and associated signaling pathways. AngII treatment of VSMC enhanced the protein synthesis that was attenuated towards control levels by RV pretreatment as well as by the inhibitors of NADPH oxidase, c-Src, and growth factor receptors. Furthermore, RV pretreatment also inhibited enhanced levels of superoxide anion, NADPH oxidase activity, increased expression of NADPH oxidase subunits, and phosphorylation of c-Src, EGF-R, PDGE-R, ERK1/2, and AKT1/2. In conclusion, these results indicate that RV attenuates AngII-induced VSMC hypertrophy through the inhibition of enhanced oxidative stress and activation of c-Src, growth factor receptors, and MAPK/AKT signaling. We suggest that RV could be used as a therapeutic agent in the treatment of vascular complications associated with hypertension and hypertrophy.

Texture-dependent effects of pseudo-chewing sound on perceived food texture and evoked feelings in response to nursing care foods.

Science.gov (United States)

Endo, Hiroshi; Ino, Shuichi; Fujisaki, Waka

2017-09-01

Because chewing sounds influence perceived food textures, unpleasant textures of texture-modified diets might be improved by chewing sound modulation. Additionally, since inhomogeneous food properties increase perceived sensory intensity, the effects of chewing sound modulation might depend on inhomogeneity. This study examined the influences of texture inhomogeneity on the effects of chewing sound modulation. Three kinds of nursing care foods in two food process types (minced-/puréed-like foods for inhomogeneous/homogeneous texture respectively) were used as sample foods. A pseudo-chewing sound presentation system, using electromyogram signals, was used to modulate chewing sounds. Thirty healthy elderly participants participated in the experiment. In two conditions with and without the pseudo-chewing sound, participants rated the taste, texture, and evoked feelings in response to sample foods. The results showed that inhomogeneity strongly influenced the perception of food texture. Regarding the effects of the pseudo-chewing sound, taste was less influenced, the perceived food texture tended to change in the minced-like foods, and evoked feelings changed in both food process types. Though there were some food-dependent differences in the effects of the pseudo-chewing sound, the presentation of the pseudo-chewing sounds was more effective in foods with an inhomogeneous texture. In addition, it was shown that the pseudo-chewing sound might have positively influenced feelings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Progenitor cells in pulmonary vascular remodeling

Science.gov (United States)

Yeager, Michael E.; Frid, Maria G.; Stenmark, Kurt R.

2011-01-01

Pulmonary hypertension is characterized by cellular and structural changes in the walls of pulmonary arteries. Intimal thickening and fibrosis, medial hypertrophy and fibroproliferative changes in the adventitia are commonly observed, as is the extension of smooth muscle into the previously non-muscularized vessels. A majority of these changes are associated with the enhanced presence of α-SM-actin+ cells and inflammatory cells. Atypical abundances of functionally distinct endothelial cells, particularly in the intima (plexiform lesions), and also in the perivascular regions, are also described. At present, neither the origin(s) of these cells nor the molecular mechanisms responsible for their accumulation, in any of the three compartments of the vessel wall, have been fully elucidated. The possibility that they arise from either resident vascular progenitors or bone marrow–derived progenitor cells is now well established. Resident vascular progenitor cells have been demonstrated to exist within the vessel wall, and in response to certain stimuli, to expand and express myofibroblastic, endothelial or even hematopoietic markers. Bone marrow–derived or circulating progenitor cells have also been shown to be recruited to sites of vascular injury and to assume both endothelial and SM-like phenotypes. Here, we review the data supporting the contributory role of vascular progenitors (including endothelial progenitor cells, smooth muscle progenitor cells, pericytes, and fibrocytes) in vascular remodeling. A more complete understanding of the processes by which progenitor cells modulate pulmonary vascular remodeling will undoubtedly herald a renaissance of therapies extending beyond the control of vascular tonicity and reduction of pulmonary artery pressure. PMID:22034593

Automatic classification of visual evoked potentials based on wavelet decomposition

Science.gov (United States)

Stasiakiewicz, Paweł; Dobrowolski, Andrzej P.; Tomczykiewicz, Kazimierz

2017-04-01

Diagnosis of part of the visual system, that is responsible for conducting compound action potential, is generally based on visual evoked potentials generated as a result of stimulation of the eye by external light source. The condition of patient's visual path is assessed by set of parameters that describe the time domain characteristic extremes called waves. The decision process is compound therefore diagnosis significantly depends on experience of a doctor. The authors developed a procedure - based on wavelet decomposition and linear discriminant analysis - that ensures automatic classification of visual evoked potentials. The algorithm enables to assign individual case to normal or pathological class. The proposed classifier has a 96,4% sensitivity at 10,4% probability of false alarm in a group of 220 cases and area under curve ROC equals to 0,96 which, from the medical point of view, is a very good result.

Gating of the vertex somatosensory and auditory evoked potential P50 and the correlation to skin conductance orienting response in healthy men

DEFF Research Database (Denmark)

Arnfred, S M; Eder, D N; Hemmingsen, R P

2001-01-01

A defect in auditory evoked potential (AEP) P50 gating supports the theory of information-processing deficits in schizophrenia. The relationship between gating of the mid-latency evoked potentials (EP) in the somatosensory and the auditory modalities has not been studied together before. In schiz...

Contact area affects frequency-dependent responses to vibration in the peripheral vascular and sensorineural systems.

Science.gov (United States)

Krajnak, Kristine; Miller, G R; Waugh, Stacey

2018-01-01

Repetitive exposure to hand-transmitted vibration is associated with development of peripheral vascular and sensorineural dysfunctions. These disorders and symptoms associated with it are referred to as hand-arm vibration syndrome (HAVS). Although the symptoms of the disorder have been well characterized, the etiology and contribution of various exposure factors to development of the dysfunctions are not well understood. Previous studies performed using a rat-tail model of vibration demonstrated that vascular and peripheral nervous system adverse effects of vibration are frequency-dependent, with vibration frequencies at or near the resonant frequency producing the most severe injury. However, in these investigations, the amplitude of the exposed tissue was greater than amplitude typically noted in human fingers. To determine how contact with vibrating source and amplitude of the biodynamic response of the tissue affects the risk of injury occurring, this study compared the influence of frequency using different levels of restraint to assess how maintaining contact of the tail with vibrating source affects the transmission of vibration. Data demonstrated that for the most part, increasing the contact of the tail with the platform by restraining it with additional straps resulted in an enhancement in transmission of vibration signal and elevation in factors associated with vascular and peripheral nerve injury. In addition, there were also frequency-dependent effects, with exposure at 250 Hz generating greater effects than vibration at 62.5 Hz. These observations are consistent with studies in humans demonstrating that greater contact and exposure to frequencies near the resonant frequency pose the highest risk for generating peripheral vascular and sensorineural dysfunction.

Forearm vascular response to nitric oxide and calcitonin gene-related peptide: comparison between migraine patients and control subjects.

NARCIS (Netherlands)

Hoon, J.N. de; Smits, P.; Troost, J.; Struijker-Boudier, H.A.; Bortel, L.M. van

2006-01-01

The forearm vascular response to nitric oxide (NO) and calcitonin gene-related peptide (CGRP) was investigated in 10 migraine patients and 10 matched control subjects. Changes in forearm blood flow (FBF) during intrabrachial infusion of: (i) serotonin (releasing endogenous NO), (ii) sodium

Vascular Remodeling in Experimental Hypertension

Directory of Open Access Journals (Sweden)

Norma R. Risler

2005-01-01

Full Text Available The basic hemodynamic abnormality in hypertension is an increased peripheral resistance that is due mainly to a decreased vascular lumen derived from structural changes in the small arteries wall, named (as a whole vascular remodeling. The vascular wall is an active, flexible, and integrated organ made up of cellular (endothelial cells, smooth muscle cells, adventitia cells, and fibroblasts and noncellular (extracellular matrix components, which in a dynamic way change shape or number, or reorganize in response to physiological and pathological stimuli, maintaining the integrity of the vessel wall in physiological conditions or participating in the vascular changes in cardiovascular diseases such as hypertension. Research focused on new signaling pathways and molecules that can participate in the mechanisms of vascular remodeling has provided evidence showing that vascular structure is not only affected by blood pressure, but also by mechanisms that are independent of the increased pressure. This review will provide an overview of the evidence, explaining some of the pathophysiologic mechanisms participating in the development of the vascular remodeling, in experimental models of hypertension, with special reference to the findings in spontaneously hypertensive rats as a model of essential hypertension, and in fructose-fed rats as a model of secondary hypertension, in the context of the metabolic syndrome. The understanding of the mechanisms producing the vascular alterations will allow the development of novel pharmacological tools for vascular protection in hypertensive disease.

What reported food-evoked emotions may add : A model to predict consumer food choice

NARCIS (Netherlands)

Gutjar, Swetlana; Dalenberg, Jelle R.; de Graaf, Cees; de Wijk, Rene A.; Palascha, Aikaterini; Renken, Remco J.; Jager, Gerry

2015-01-01

Food-evoked emotions provide information that goes beyond the information from traditional hedonic ratings. The objectives of our study were: (i) to investigate how intrinsic (sensory) and extrinsic (packaging) cues affect consumers' emotional responses to foods, and (ii) to explore whether

What reported food-evoked emotions may add: A model to predict consumer food choice

NARCIS (Netherlands)

Gutjar, S.; Dalenberg, J.R.; Graaf, de C.; Wijk, de R.A.; Palascha, A.; Renken, Remco J.; Jager, G.

2015-01-01

Food-evoked emotions provide information that goes beyond the information from traditional hedonic ratings. The objectives of our study were: (i) to investigate how intrinsic (sensory) and extrinsic (packaging) cues affect consumers’ emotional responses to foods, and (ii) to explore whether

[Recognition of the spatially transformed objects in men and women: an analysis of the behavior and evoked potentials].

Science.gov (United States)

Slavutskaia, A V; Gerasimenko, N Iu; Mikhaĭlova, E S

2012-01-01

In 16 men and 15 women analyzed the accuracy, reaction time and visual evoked potentials during the recognition of familiar objects at different levels of spatial transformation. We used the three levels of transformation: in a fixed position relative to each other details were carried out (1) the displacement of all the details in the radial direction and (2 and 3) a similar shift in conjunction with the rotation of all the details of the figure by +/- 0-45 and +/- 45-90 degrees. The task performance was not dependent on gender: the transformation of the image led to a deterioration of identification with the most identification impairment in the case of maximal details' rotation. Changes in evoked potentials (ERP) are different for men and women. Only in men early (100 ms after stimulus) response of the parietal cortex associated with the level of figure transformation: the more rotation evoked the higher the response. In women figure transformation evoked the ERP changes in the time window of negativity N170, they are associated with figure ungrouping but not with details rotation, and are localized in other visual areas--occipital and temporal. The data obtained are discussed in light of theory of gender specificity of the visual representations of space.

The surrounding tissue modifies the placental stem villous vascular responses

DEFF Research Database (Denmark)

Brøgger, Torbjørn; Forman, Axel; Aalkjær, Christian

2014-01-01

is available. In-depth understanding of the mechanisms involved in control of placental vascular tone are needed to develop new tissue targets for therapeutic intervention. Method: From fresh born placentas segments of stem villous arteries were carefully dissected. The artery branches were divided....... The surrounding trophoblast was removed from one end and left intact in the other, and the segment was divided to give two ring preparations, with or without trophoblast. The preparations were mounted in wire myographs and responses to vasoactive agents were compared. Results: pD2values for PGF2α, Tx-analog U...... or endotheline-1. These differences partly disappeared in the presence of L-NAME. Conclusion: The perivascular tissue significantly reduces sensitivity and force development of stem villous arteries, partly due to release of NO This represents a new mechanism for control of human stem villous artery tone....

Lifting the veil on the dynamics of neuronal activities evoked by transcranial magnetic stimulation.

Science.gov (United States)

Li, Bingshuo; Virtanen, Juha P; Oeltermann, Axel; Schwarz, Cornelius; Giese, Martin A; Ziemann, Ulf; Benali, Alia

2017-11-22

Transcranial magnetic stimulation (TMS) is a widely used non-invasive tool to study and modulate human brain functions. However, TMS-evoked activity of individual neurons has remained largely inaccessible due to the large TMS-induced electromagnetic fields. Here, we present a general method providing direct in vivo electrophysiological access to TMS-evoked neuronal activity 0.8-1 ms after TMS onset. We translated human single-pulse TMS to rodents and unveiled time-grained evoked activities of motor cortex layer V neurons that show high-frequency spiking within the first 6 ms depending on TMS-induced current orientation and a multiphasic spike-rhythm alternating between excitation and inhibition in the 6-300 ms epoch, all of which can be linked to various human TMS responses recorded at the level of spinal cord and muscles. The advance here facilitates a new level of insight into the TMS-brain interaction that is vital for developing this non-invasive tool to purposefully explore and effectively treat the human brain.

Brainstem Auditory Evoked Potential in HIV-Positive Adults.

Science.gov (United States)

Matas, Carla Gentile; Samelli, Alessandra Giannella; Angrisani, Rosanna Giaffredo; Magliaro, Fernanda Cristina Leite; Segurado, Aluísio C

2015-10-20

To characterize the findings of brainstem auditory evoked potential in HIV-positive individuals exposed and not exposed to antiretroviral treatment. This research was a cross-sectional, observational, and descriptive study. Forty-five HIV-positive individuals (18 not exposed and 27 exposed to the antiretroviral treatment - research groups I and II, respectively - and 30 control group individuals) were assessed through brainstem auditory evoked potential. There were no significant between-group differences regarding wave latencies. A higher percentage of altered brainstem auditory evoked potential was observed in the HIV-positive groups when compared to the control group. The most common alteration was in the low brainstem. HIV-positive individuals have a higher percentage of altered brainstem auditory evoked potential that suggests central auditory pathway impairment when compared to HIV-negative individuals. There was no significant difference between individuals exposed and not exposed to antiretroviral treatment.

Angiotensin II and CRF receptors in the central nucleus of the amygdala mediate hemodynamic response variability to cocaine in conscious rats.

Science.gov (United States)

Watanabe, Mari A; Kucenas, Sarah; Bowman, Tamara A; Ruhlman, Melissa; Knuepfer, Mark M

2010-01-14

Stress or cocaine evokes either a large increase in systemic vascular resistance (SVR) or a smaller increase in SVR accompanied by an increase in cardiac output (designated vascular and mixed responders, respectively) in Sprague-Dawley rats. We hypothesized that the central nucleus of the amygdala (CeA) mediates this variability. Conscious, freely-moving rats, instrumented for measurement of arterial pressure and cardiac output and for drug delivery into the CeA, were given cocaine (5 mg/kg, iv, 4-6 times) and characterized as vascular (n=15) or mixed responders (n=10). Subsequently, we administered cocaine after bilateral microinjections (100 nl) of saline or selective agents in the CeA. Muscimol (80 pmol), a GABA(A) agonist, or losartan (43.4 pmol), an AT(1) receptor antagonist, attenuated the cocaine-induced increase in SVR in vascular responders, selectively, such that vascular responders were no longer different from mixed responders. The corticotropin releasing factor (CRF) antagonist, alpha-helical CRF(9-41) (15.7 pmol), abolished the difference between cardiac output and SVR in mixed and vascular responders. We conclude that greater increases in SVR observed in vascular responders are dependent on AT(1) receptor activation and, to a lesser extent on CRF receptors. Therefore, AT(1) and CRF receptors in the CeA contribute to hemodynamic response variability to intravenous cocaine.

Torque decrease during submaximal evoked contractions of the quadriceps muscle is linked not only to muscle fatigue.

Science.gov (United States)

Matkowski, Boris; Lepers, Romuald; Martin, Alain

2015-05-01

The aim of this study was to analyze the neuromuscular mechanisms involved in the torque decrease induced by submaximal electromyostimulation (EMS) of the quadriceps muscle. It was hypothesized that torque decrease after EMS would reflect the fatigability of the activated motor units (MUs), but also a reduction in the number of MUs recruited as a result of changes in axonal excitability threshold. Two experiments were performed on 20 men to analyze 1) the supramaximal twitch superimposed and evoked at rest during EMS (Experiment 1, n = 9) and 2) the twitch response and torque-frequency relation of the MUs activated by EMS (Experiment 2, n = 11). Torque loss was assessed by 15 EMS-evoked contractions (50 Hz; 6 s on/6 s off), elicited at a constant intensity that evoked 20% of the maximal voluntary contraction (MVC) torque. The same stimulation intensity delivered over the muscles was used to induce the torque-frequency relation and the single electrical pulse evoked after each EMS contraction (Experiment 2). In Experiment 1, supramaximal twitch was induced by femoral nerve stimulation. Torque decreased by ~60% during EMS-evoked contractions and by only ~18% during MVCs. This was accompanied by a rightward shift of the torque-frequency relation of MUs activated and an increase of the ratio between the superimposed and posttetanic maximal twitch evoked during EMS contraction. These findings suggest that the torque decrease observed during submaximal EMS-evoked contractions involved muscular mechanisms but also a reduction in the number of MUs recruited due to changes in axonal excitability. Copyright © 2015 the American Physiological Society.

Video outside versus video inside the web: do media setting and image size have an impact on the emotion-evoking potential of video?

NARCIS (Netherlands)

Verleur, R.; Verhagen, Pleunes Willem; Crawford, Margaret; Simonson, Michael; Lamboy, Carmen

2001-01-01

To explore the educational potential of video-evoked affective responses in a Web-based environment, the question was raised whether video in a Web-based environment is experienced differently from video in a traditional context. An experiment was conducted that studied the affect-evoking power of

Pathway-specific variations in neurovascular and neurometabolic coupling in rat primary somatosensory cortex

DEFF Research Database (Denmark)

Enager, Pia; Hansen, Henning Piilgaard; Offenhauser, Nikolas

2009-01-01

Functional neuroimaging signals are generated, in part, by increases in cerebral blood flow (CBF) evoked by mediators, such as nitric oxide and arachidonic acid derivatives that are released in response to increased neurotransmission. However, it is unknown whether the vascular and metabolic resp...... critically on the type of input, and that a positive blood oxygen level-dependent (BOLD) signal may be a consequence of the activation of both pyramidal cells and inhibitory interneurons.......Functional neuroimaging signals are generated, in part, by increases in cerebral blood flow (CBF) evoked by mediators, such as nitric oxide and arachidonic acid derivatives that are released in response to increased neurotransmission. However, it is unknown whether the vascular and metabolic...... different inputs to a single cortical area. We show that, for a given level of glutamatergic synaptic activity, corticocortical and thalamocortical inputs evoked activity in pyramidal cells and different classes of interneurons, and produced different changes in oxygen consumption and CBF. Furthermore...

Deficiency of superoxide dismutase promotes cerebral vascular hypertrophy and vascular dysfunction in hyperhomocysteinemia.

Directory of Open Access Journals (Sweden)

Sanjana Dayal

Full Text Available There is an emerging consensus that hyperhomocysteinemia is an independent risk factor for cerebral vascular disease and that homocysteine-lowering therapy protects from ischemic stroke. However, the mechanisms by which hyperhomocysteinemia produces abnormalities of cerebral vascular structure and function remain largely undefined. Our objective in this study was to define the mechanistic role of superoxide in hyperhomocysteinemia-induced cerebral vascular dysfunction and hypertrophy. Unlike previous studies, our experimental design included a genetic approach to alter superoxide levels by using superoxide dismutase 1 (SOD1-deficient mice fed a high methionine/low folate diet to produce hyperhomocysteinemia. In wild-type mice, the hyperhomocysteinemic diet caused elevated superoxide levels and impaired responses to endothelium-dependent vasodilators in cerebral arterioles, and SOD1 deficiency compounded the severity of these effects. The cross-sectional area of the pial arteriolar wall was markedly increased in mice with SOD1 deficiency, and the hyperhomocysteinemic diet sensitized SOD1-deficient mice to this hypertrophic effect. Analysis of individual components of the vascular wall demonstrated a significant increase in the content of smooth muscle and elastin. We conclude that superoxide is a key driver of both cerebral vascular hypertrophy and vasomotor dysfunction in this model of dietary hyperhomocysteinemia. These findings provide insight into the mechanisms by which hyperhomocysteinemia promotes cerebral vascular disease and ischemic stroke.

[Cortical potentials evoked to response to a signal to make a memory-guided saccade].

Science.gov (United States)

Slavutskaia, M V; Moiseeva, V V; Shul'govskiĭ, V V

2010-01-01

The difference in parameters of visually guided and memory-guided saccades was shown. Increase in the memory-guided saccade latency as compared to that of the visually guided saccades may indicate the deceleration of saccadic programming on the basis of information extraction from the memory. The comparison of parameters and topography of evoked components N1 and P1 of the evoked potential on the signal to make a memory- or visually guided saccade suggests that the early stage of the saccade programming associated with the space information processing is performed predominantly with top-down attention mechanism before the memory-guided saccade and bottom-up mechanism before the visually guided saccade. The findings show that the increase in the latency of the memory-guided saccades is connected with decision making at the central stage of the saccade programming. We proposed that wave N2, which develops in the middle of the latent period of the memory-guided saccades, is correlated with this process. Topography and spatial dynamics of components N1, P1 and N2 testify that the memory-guided saccade programming is controlled by the frontal mediothalamic system of selective attention and left-hemispheric brain mechanisms of motor attention.

Prediction of heat-illness symptoms with the prediction of human vascular response in hot environment under resting condition.

Science.gov (United States)

Aggarwal, Yogender; Karan, Bhuwan Mohan; Das, Barsa Nand; Sinha, Rakesh Kumar

2008-04-01

The thermoregulatory control of human skin blood flow is vital to maintain the body heat storage during challenges of thermal homeostasis under heat stress. Whenever thermal homeostasis disturbed, the heat load exceeds heat dissipation capacity, which alters the cutaneous vascular responses along with other body physiological variables. Whole body skin blood flow has been calculated from the forearm blood flow. Present model has been designed using electronics circuit simulator (Multisim 8.0, National Instruments, USA), is to execute a series of predictive equations for early prediction of physiological parameters of young nude subjects during resting condition at various level of dry heat stress under almost still air to avoid causalities associated with hot environmental. The users can execute the model by changing the environmental temperature in degrees C and exposure time in minutes. The model would be able to predict and detect the changes in human vascular responses along with other physiological parameters and from this predicted values heat related-illness symptoms can be inferred.

Electroencephalographic evoked pain response is suppressed by spinal cord stimulation in complex regional pain syndrome: a case report.

Science.gov (United States)

Hylands-White, Nicholas; Duarte, Rui V; Beeson, Paul; Mayhew, Stephen D; Raphael, Jon H

2016-12-01

Pain is a subjective response that limits assessment. The purpose of this case report was to explore how the objectivity of the electroencephalographic response to thermal stimuli would be affected by concurrent spinal cord stimulation. A patient had been implanted with a spinal cord stimulator for the management of complex regional pain syndrome of both hands for 8 years. Following ethical approval and written informed consent we induced thermal stimuli using the Medoc PATHWAY Pain & Sensory Evaluation System on the right hand of the patient with the spinal cord stimulator switched off and with the spinal cord stimulator switched on. The patient reported a clinically significant reduction in thermal induced pain using the numerical rating scale (71.4 % reduction) with spinal cord stimulator switched on. Analysis of electroencephalogram recordings indicated the occurrence of contact heat evoked potentials (N2-P2) with spinal cord stimulator off, but not with spinal cord stimulator on. This case report suggests that thermal pain can be reduced in complex regional pain syndrome patients with the use of spinal cord stimulation and offers objective validation of the reported outcomes with this treatment.

[Effects of sevoflurane and propofol on evoked potentials during neurosurgical anesthesia].

Science.gov (United States)

Nakagawa, Itsuo; Hidaka, Syozo; Okada, Hironori; Kubo, Takashi; Okamura, Kenta; Kato, Takahiro

2006-06-01

The effect of anesthetics on somatosensory evoked potential (SEP) and auditory brain stem response (ABR) has been a subject of intense reseach over the last two decades. In fact, volatile anesthetics have been repeatedly shown to decrease cortical amplitude in a dose-dependent fashion but the information regarding the effect of propofol is incomplete. The purpose of this study was to compare the effects of sevoflurane and propofol on evoked potentials during comparable depth of anesthesia guided by bispectral index (BIS). Forty four patients scheduled for neurosurgery were studied. Anesthesia was maintained with intravenous propofol using target controlled infusion (TCI). We measured the change of amplitude and latency of SEP(N20-P25), ABR (V wave) and visual evoked potential (VEP: P100) at three sets of sevoflurane (0%, 1%, 2%) or propofol concentrations (effect site concentration of 1.5, 2.0, 3.0 microug x ml(-1)). BIS monitor was used to measure relative depth of hypnosis. With increasing concentrations of sevoflurane (0, 1% and 2%), SEP showed dose-related reduction in its amplitude, ABR produced less marked changes and VEP showed a significant reduction at 1%. VEP at the propofol concentration of 3.0 microg x ml(-1) was decreased significantly compared with the amplitude at 1.5 microg x ml(-1) concentration. No significant change was observed with SEP and ABR during the change of propofol dosages. BIS values were almost the same with each anesthetics. VEP was most strongly affected with anesthetics, and ABR showed less marked influence of sevoflurane and propofol. Propofol based TIVA technique would induce less change in evoked potentials than sevoflurane.

Perceptual learning of acoustic noise generates memory-evoked potentials.

Science.gov (United States)

Andrillon, Thomas; Kouider, Sid; Agus, Trevor; Pressnitzer, Daniel

2015-11-02

Experience continuously imprints on the brain at all stages of life. The traces it leaves behind can produce perceptual learning [1], which drives adaptive behavior to previously encountered stimuli. Recently, it has been shown that even random noise, a type of sound devoid of acoustic structure, can trigger fast and robust perceptual learning after repeated exposure [2]. Here, by combining psychophysics, electroencephalography (EEG), and modeling, we show that the perceptual learning of noise is associated with evoked potentials, without any salient physical discontinuity or obvious acoustic landmark in the sound. Rather, the potentials appeared whenever a memory trace was observed behaviorally. Such memory-evoked potentials were characterized by early latencies and auditory topographies, consistent with a sensory origin. Furthermore, they were generated even on conditions of diverted attention. The EEG waveforms could be modeled as standard evoked responses to auditory events (N1-P2) [3], triggered by idiosyncratic perceptual features acquired through learning. Thus, we argue that the learning of noise is accompanied by the rapid formation of sharp neural selectivity to arbitrary and complex acoustic patterns, within sensory regions. Such a mechanism bridges the gap between the short-term and longer-term plasticity observed in the learning of noise [2, 4-6]. It could also be key to the processing of natural sounds within auditory cortices [7], suggesting that the neural code for sound source identification will be shaped by experience as well as by acoustics. Copyright © 2015 Elsevier Ltd. All rights reserved.

High-frequency combination coding-based steady-state visual evoked potential for brain computer interface

Energy Technology Data Exchange (ETDEWEB)

Zhang, Feng; Zhang, Xin; Xie, Jun; Li, Yeping; Han, Chengcheng; Lili, Li; Wang, Jing [School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Xu, Guang-Hua [School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710054 (China)

2015-03-10

This study presents a new steady-state visual evoked potential (SSVEP) paradigm for brain computer interface (BCI) systems. The goal of this study is to increase the number of targets using fewer stimulation high frequencies, with diminishing subject’s fatigue and reducing the risk of photosensitive epileptic seizures. The new paradigm is High-Frequency Combination Coding-Based High-Frequency Steady-State Visual Evoked Potential (HFCC-SSVEP).Firstly, we studied SSVEP high frequency(beyond 25 Hz)response of SSVEP, whose paradigm is presented on the LED. The SNR (Signal to Noise Ratio) of high frequency(beyond 40 Hz) response is very low, which is been unable to be distinguished through the traditional analysis method; Secondly we investigated the HFCC-SSVEP response (beyond 25 Hz) for 3 frequencies (25Hz, 33.33Hz, and 40Hz), HFCC-SSVEP produces n{sup n} with n high stimulation frequencies through Frequence Combination Code. Further, Animproved Hilbert-huang transform (IHHT)-based variable frequency EEG feature extraction method and a local spectrum extreme target identification algorithmare adopted to extract time-frequency feature of the proposed HFCC-SSVEP response.Linear predictions and fixed sifting (iterating) 10 time is used to overcome the shortage of end effect and stopping criterion,generalized zero-crossing (GZC) is used to compute the instantaneous frequency of the proposed SSVEP respondent signals, the improved HHT-based feature extraction method for the proposed SSVEP paradigm in this study increases recognition efficiency, so as to improve ITR and to increase the stability of the BCI system. what is more, SSVEPs evoked by high-frequency stimuli (beyond 25Hz) minimally diminish subject’s fatigue and prevent safety hazards linked to photo-induced epileptic seizures, So as to ensure the system efficiency and undamaging.This study tests three subjects in order to verify the feasibility of the proposed method.

High-frequency combination coding-based steady-state visual evoked potential for brain computer interface

International Nuclear Information System (INIS)

Zhang, Feng; Zhang, Xin; Xie, Jun; Li, Yeping; Han, Chengcheng; Lili, Li; Wang, Jing; Xu, Guang-Hua

2015-01-01

This study presents a new steady-state visual evoked potential (SSVEP) paradigm for brain computer interface (BCI) systems. The goal of this study is to increase the number of targets using fewer stimulation high frequencies, with diminishing subject’s fatigue and reducing the risk of photosensitive epileptic seizures. The new paradigm is High-Frequency Combination Coding-Based High-Frequency Steady-State Visual Evoked Potential (HFCC-SSVEP).Firstly, we studied SSVEP high frequency(beyond 25 Hz)response of SSVEP, whose paradigm is presented on the LED. The SNR (Signal to Noise Ratio) of high frequency(beyond 40 Hz) response is very low, which is been unable to be distinguished through the traditional analysis method; Secondly we investigated the HFCC-SSVEP response (beyond 25 Hz) for 3 frequencies (25Hz, 33.33Hz, and 40Hz), HFCC-SSVEP produces n n with n high stimulation frequencies through Frequence Combination Code. Further, Animproved Hilbert-huang transform (IHHT)-based variable frequency EEG feature extraction method and a local spectrum extreme target identification algorithmare adopted to extract time-frequency feature of the proposed HFCC-SSVEP response.Linear predictions and fixed sifting (iterating) 10 time is used to overcome the shortage of end effect and stopping criterion,generalized zero-crossing (GZC) is used to compute the instantaneous frequency of the proposed SSVEP respondent signals, the improved HHT-based feature extraction method for the proposed SSVEP paradigm in this study increases recognition efficiency, so as to improve ITR and to increase the stability of the BCI system. what is more, SSVEPs evoked by high-frequency stimuli (beyond 25Hz) minimally diminish subject’s fatigue and prevent safety hazards linked to photo-induced epileptic seizures, So as to ensure the system efficiency and undamaging.This study tests three subjects in order to verify the feasibility of the proposed method

Correlation between single-trial visual evoked potentials and the blood oxygenation level dependent response in simultaneously recorded electroencephalography-functional magnetic resonance imaging

DEFF Research Database (Denmark)

Fuglø, Dan; Pedersen, Henrik; Rostrup, Egill

2012-01-01

in different occipital and extraoccipital cortical areas not explained by the boxcar regressor. The results suggest that the P1-N2 regressor is the best EEG-based regressor to model the visual paradigm, but when looking for additional effects like habituation or attention modulation that cannot be modeled......To compare different electroencephalography (EEG)-based regressors and their ability to predict the simultaneously recorded blood oxygenation level dependent response during blocked visual stimulation, simultaneous EEG-functional magnetic resonance imaging in 10 healthy volunteers was performed....... The performance of different single-trial EEG regressors was compared in terms of predicting the measured blood oxygenation level dependent response. The EEG-based regressors were the amplitude and latency of the primary positive (P1) and negative (N2) peaks of the visual evoked potential, the combined P1-N2...

Can visual evoked potentials be used in biometric identification?

Science.gov (United States)

Power, Alan J; Lalor, Edmund C; Reilly, Richard B

2006-01-01

Due to known differences in the anatomical structure of the visual pathways and generators in different individuals, the use of visual evoked potentials offers the possibility of an alternative to existing biometrics methods. A study based on visual evoked potentials from 13 individuals was carried out to assess the best combination of temporal, spectral and AR modeling features to realize a robust biometric. From the results it can be concluded that visual evoked potentials show considerable biometric qualities, with classification accuracies reaching a high of 86.54% and that a specific temporal and spectral combination was found to be optimal. Based on these results the visual evoked potential may be a useful tool in biometric identification when used in conjunction with more established biometric methods.

Temperature and nucleotide dependence of calcium release by myo-inositol 1,4,5-trisphosphate in cultured vascular smooth muscle cells

International Nuclear Information System (INIS)

Smith, J.B.; Smith, L.; Higgins, B.L.

1985-01-01

Inositol 1,4,5-trisphosphate (IP3) rapidly increased 45 Ca 2+ efflux from a nonmitochondrial organelle in cultured vascular smooth muscle cells that were permeabilized with saponin. A nucleotide, preferably ATP, was essential for IP3-evoked 45 Ca 2+ release. Two nonhydrolyzable ATP analogues satisfied the nucleotide requirement for IP3-evoked 45 Ca 2+ release. IP3 strongly stimulated 45 Ca 2+ efflux at low temperatures (1 to 15 degrees C). Decreasing the temperature from 37 to 4 degrees C inhibited the rate of IP3-stimulated efflux by only about 33%. The failure of such low temperatures to strongly inhibit IP3-induced 45 Ca 2+ efflux suggests that IP3 activated a Ca 2+ channel, rather than a carrier, by a ligand-binding, rather than a metabolic, reaction

Contribution of resolved and unresolved harmonic regions to brainstem speech-evoked responses in quiet and in background noise

Directory of Open Access Journals (Sweden)

M. Laroche

2011-03-01

Full Text Available Speech auditory brainstem responses (speech ABR reflect activity that is phase-locked to the harmonics of the fundamental frequency (F0 up to at least the first formant (F1. Recent evidence suggests that responses at F0 in the presence of noise are more robust than responses at F1, and are also dissociated in some learning-impaired children. Peripheral auditory processing can be broadly divided into resolved and unresolved harmonic regions. This study investigates the contribution of these two regions to the speech ABR, and their susceptibility to noise. We recorded, in quiet and in background white noise, evoked responses in twelve normal hearing adults in response to three variants of a synthetic vowel: i Allformants, which contains all first three formants, ii F1Only, which is dominated by resolved harmonics, and iii F2&F3Only, which is dominated by unresolved harmonics. There were no statistically significant differences in the response at F0 due to the three variants of the stimulus in quiet, nor did the noise affect this response with the Allformants and F1Only variants. On the other hand, the response at F0 with the F2&F3Only variant was significantly weaker in noise than with the two other variants (p<0.001. With the response at F1, there was no difference with the Allformants and F1Only variants in quiet, but was expectedly weaker with the F2&F3Only variant (p<0.01. The addition of noise significantly weakened the response at F1 with the F1Only variant (p<0.05, but this weakening only tended towards significance with the Allformants variant (p=0.07. The results of this study indicate that resolved and unresolved harmonics are processed in different but interacting pathways that converge in the upper brainstem. The results also support earlier work on the differential susceptibility of responses at F0 and F1 to added noise.

Sound-Making Actions Lead to Immediate Plastic Changes of Neuromagnetic Evoked Responses and Induced β-Band Oscillations during Perception.

Science.gov (United States)

Ross, Bernhard; Barat, Masihullah; Fujioka, Takako

2017-06-14

Auditory and sensorimotor brain areas interact during the action-perception cycle of sound making. Neurophysiological evidence of a feedforward model of the action and its outcome has been associated with attenuation of the N1 wave of auditory evoked responses elicited by self-generated sounds, such as talking and singing or playing a musical instrument. Moreover, neural oscillations at β-band frequencies have been related to predicting the sound outcome after action initiation. We hypothesized that a newly learned action-perception association would immediately modify interpretation of the sound during subsequent listening. Nineteen healthy young adults (7 female, 12 male) participated in three magnetoencephalographic recordings while first passively listening to recorded sounds of a bell ringing, then actively striking the bell with a mallet, and then again listening to recorded sounds. Auditory cortex activity showed characteristic P1-N1-P2 waves. The N1 was attenuated during sound making, while P2 responses were unchanged. In contrast, P2 became larger when listening after sound making compared with the initial naive listening. The P2 increase occurred immediately, while in previous learning-by-listening studies P2 increases occurred on a later day. Also, reactivity of β-band oscillations, as well as θ coherence between auditory and sensorimotor cortices, was stronger in the second listening block. These changes were significantly larger than those observed in control participants (eight female, five male), who triggered recorded sounds by a key press. We propose that P2 characterizes familiarity with sound objects, whereas β-band oscillation signifies involvement of the action-perception cycle, and both measures objectively indicate functional neuroplasticity in auditory perceptual learning. SIGNIFICANCE STATEMENT While suppression of auditory responses to self-generated sounds is well known, it is not clear whether the learned action-sound association

Binaural interaction in auditory evoked potentials: Brainstem, middle- and long-latency components

OpenAIRE

McPherson, DL; Starr, A

1993-01-01

Binaural interaction occurs in the auditory evoked potentials when the sum of the monaural auditory evoked potentials are not equivalent to the binaural evoked auditory potentials. Binaural interaction of the early- (0-10 ms), middle- (10-50 ms) and long-latency (50-200 ms) auditory evoked potentials was studied in 17 normal young adults. For the early components, binaural interaction was maximal at 7.35 ms accounting for a reduction of 21% of the amplitude of the binaural evoked potentials. ...

Longitudinal visualization of vascular occlusion, reperfusion, and remodeling in a zebrafish model of retinal vascular leakage using OCT angiography

Science.gov (United States)

Spitz, Kathleen; Bozic, Ivan; Desai, Vineet; Rao, Gopikrishna M.; Pollock, Lana M.; Anand-Apte, Bela; Tao, Yuankai K.

2017-02-01

Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are two of the leading causes of blindness and visual impairment in the world. Neovascularization results in severe vision loss in DR and AMD and, thus, there is an unmet need to identify mechanisms of pathogenesis and novel anti-angiogenic therapies. Zebrafish is a leading model organism for studying human disease pathogenesis, and the highly conserved drug activity between zebrafish and humans and their ability to readily absorb small molecules dissolved in water has benefited pharmaceutical discovery. Here, we use optical coherence tomography (OCT) and OCT angiography (OCT-A) to perform noninvasive, in vivo retinal imaging in a zebrafish model of vascular leakage. Zebrafish were treated with diethylaminobenzaldehyde (DEAB) to induce vascular leakage and imaged with OCT and OCT-A at six time points over two weeks: baseline one day before treatment and one, three, six, eight, and ten days post treatment. Longitudinal functional imaging showed significant vascular response immediately after DEAB treatment. Observed vascular changes included partial or complete vascular occlusion immediately after treatment and reperfusion during a two-week period. Increased vascular tortuosity several days post treatment indicated remodeling, and bifurcations and collateral vessel formation were also observed. In addition, significant treatment response variabilities were observed in the contralateral eye of the same animal. Anatomical and functional normalization was observed in most animals by ten days post treatment. These preliminary results motivate potential applications of OCT-A as a tool for studying pathogenesis and therapeutic screening in zebrafish models of retinal vascular disease.

Feasibility and performance evaluation of generating and recording visual evoked potentials using ambulatory Bluetooth based system.

Science.gov (United States)

Ellingson, Roger M; Oken, Barry

2010-01-01

Report contains the design overview and key performance measurements demonstrating the feasibility of generating and recording ambulatory visual stimulus evoked potentials using the previously reported custom Complementary and Alternative Medicine physiologic data collection and monitoring system, CAMAS. The methods used to generate visual stimuli on a PDA device and the design of an optical coupling device to convert the display to an electrical waveform which is recorded by the CAMAS base unit are presented. The optical sensor signal, synchronized to the visual stimulus emulates the brain's synchronized EEG signal input to CAMAS normally reviewed for the evoked potential response. Most importantly, the PDA also sends a marker message over the wireless Bluetooth connection to the CAMAS base unit synchronized to the visual stimulus which is the critical averaging reference component to obtain VEP results. Results show the variance in the latency of the wireless marker messaging link is consistent enough to support the generation and recording of visual evoked potentials. The averaged sensor waveforms at multiple CPU speeds are presented and demonstrate suitability of the Bluetooth interface for portable ambulatory visual evoked potential implementation on our CAMAS platform.

Modeling the Developmental Patterns of Auditory Evoked Magnetic Fields in Children

OpenAIRE

Kotecha, Rupesh; Pardos, Maria; Wang, Yingying; Wu, Ting; Horn, Paul; Brown, David; Rose, Douglas; deGrauw, Ton; Xiang, Jing

2009-01-01

BACKGROUND: As magnetoencephalography (MEG) is of increasing utility in the assessment of deficits and development delays in brain disorders in pediatrics, it becomes imperative to fully understand the functional development of the brain in children. METHODOLOGY: The present study was designed to characterize the developmental patterns of auditory evoked magnetic responses with respect to age and gender. Sixty children and twenty adults were studied with a 275-channel MEG system. CONCLUSIONS:...

Lifting the veil on the dynamics of neuronal activities evoked by transcranial magnetic stimulation

Science.gov (United States)

Li, Bingshuo; Virtanen, Juha P; Oeltermann, Axel; Schwarz, Cornelius; Giese, Martin A; Ziemann, Ulf

2017-01-01

Transcranial magnetic stimulation (TMS) is a widely used non-invasive tool to study and modulate human brain functions. However, TMS-evoked activity of individual neurons has remained largely inaccessible due to the large TMS-induced electromagnetic fields. Here, we present a general method providing direct in vivo electrophysiological access to TMS-evoked neuronal activity 0.8–1 ms after TMS onset. We translated human single-pulse TMS to rodents and unveiled time-grained evoked activities of motor cortex layer V neurons that show high-frequency spiking within the first 6 ms depending on TMS-induced current orientation and a multiphasic spike-rhythm alternating between excitation and inhibition in the 6–300 ms epoch, all of which can be linked to various human TMS responses recorded at the level of spinal cord and muscles. The advance here facilitates a new level of insight into the TMS-brain interaction that is vital for developing this non-invasive tool to purposefully explore and effectively treat the human brain. PMID:29165241

Modeling the developmental patterns of auditory evoked magnetic fields in children.

Directory of Open Access Journals (Sweden)

Rupesh Kotecha

Full Text Available BACKGROUND: As magnetoencephalography (MEG is of increasing utility in the assessment of deficits and development delays in brain disorders in pediatrics, it becomes imperative to fully understand the functional development of the brain in children. METHODOLOGY: The present study was designed to characterize the developmental patterns of auditory evoked magnetic responses with respect to age and gender. Sixty children and twenty adults were studied with a 275-channel MEG system. CONCLUSIONS: Three main responses were identified at approximately 46 ms (M50, 71 ms (M70 and 106 ms (M100 in latency for children. The latencies of M70 and M100 shortened with age in both hemispheres; the latency of M50 shortened with age only in the right hemisphere. Analysis of developmental lateralization patterns in children showed that the latency of the right hemispheric evoked responses shortened faster than the corresponding left hemispheric responses. The latency of M70 in the right hemisphere highly correlated to the age of the child. The amplitudes of the M70 responses increased with age and reached their peaks in children 12-14 years of age, after which they decreased with age. The source estimates for the M50 and M70 responses indicated that they were generated in different subareas in the Heschl's gyrus in children, while not localizable in adults. Furthermore, gender also affected developmental patterns. The latency of M70 in the right hemisphere was proposed to be an index of auditory development in children, the modeling equation is 85.72-1.240xAge (yrs. Our results demonstrate that there is a clear developmental pattern in the auditory cortex and underscore the importance of M50 and M70 in the developing brain.

Bioprinting for vascular and vascularized tissue biofabrication.

Science.gov (United States)

Datta, Pallab; Ayan, Bugra; Ozbolat, Ibrahim T

2017-03-15

Bioprinting is a promising technology to fabricate design-specific tissue constructs due to its ability to create complex, heterocellular structures with anatomical precision. Bioprinting enables the deposition of various biologics including growth factors, cells, genes, neo-tissues and extra-cellular matrix-like hydrogels. Benefits of bioprinting have started to make a mark in the fields of tissue engineering, regenerative medicine and pharmaceutics. Specifically, in the field of tissue engineering, the creation of vascularized tissue constructs has remained a principal challenge till date. However, given the myriad advantages over other biofabrication methods, it becomes organic to expect that bioprinting can provide a viable solution for the vascularization problem, and facilitate the clinical translation of tissue engineered constructs. This article provides a comprehensive account of bioprinting of vascular and vascularized tissue constructs. The review is structured as introducing the scope of bioprinting in tissue engineering applications, key vascular anatomical features and then a thorough coverage of 3D bioprinting using extrusion-, droplet- and laser-based bioprinting for fabrication of vascular tissue constructs. The review then provides the reader with the use of bioprinting for obtaining thick vascularized tissues using sacrificial bioink materials. Current challenges are discussed, a comparative evaluation of different bioprinting modalities is presented and future prospects are provided to the reader. Biofabrication of living tissues and organs at the clinically-relevant volumes vitally depends on the integration of vascular network. Despite the great progress in traditional biofabrication approaches, building perfusable hierarchical vascular network is a major challenge. Bioprinting is an emerging technology to fabricate design-specific tissue constructs due to its ability to create complex, heterocellular structures with anatomical precision

Vascular disease in cocaine addiction.

Science.gov (United States)

Bachi, Keren; Mani, Venkatesh; Jeyachandran, Devi; Fayad, Zahi A; Goldstein, Rita Z; Alia-Klein, Nelly

2017-07-01

Cocaine, a powerful vasoconstrictor, induces immune responses including cytokine elevations. Chronic cocaine use is associated with functional brain impairments potentially mediated by vascular pathology. Although the Crack-Cocaine epidemic has declined, its vascular consequences are increasingly becoming evident among individuals with cocaine use disorder of that period, now aging. Paradoxically, during the period when prevention efforts could make a difference, this population receives psychosocial treatment at best. We review major postmortem and in vitro studies documenting cocaine-induced vascular toxicity. PubMed and Academic Search Complete were used with relevant terms. Findings consist of the major mechanisms of cocaine-induced vasoconstriction, endothelial dysfunction, and accelerated atherosclerosis, emphasizing acute, chronic, and secondary effects of cocaine. The etiology underlying cocaine's acute and chronic vascular effects is multifactorial, spanning hypertension, impaired homeostasis and platelet function, thrombosis, thromboembolism, and alterations in blood flow. Early detection of vascular disease in cocaine addiction by multimodality imaging is discussed. Treatment may be similar to indications in patients with traditional risk-factors, with few exceptions such as enhanced supportive care and use of benzodiazepines and phentolamine for sedation, and avoiding β-blockers. Given the vascular toxicity cocaine induces, further compounded by smoking and alcohol comorbidity, and interacting with aging of the crack generation, there is a public health imperative to identify pre-symptomatic markers of vascular impairments in cocaine addiction and employ preventive treatment to reduce silent disease progression. Copyright © 2017 Elsevier B.V. All rights reserved.

Slow cortical evoked potentials after noise exposure

Energy Technology Data Exchange (ETDEWEB)

von Wedel, H; Opitz, H J

1979-07-01

Human cortical evoked potentials under conditions of stimuation are registrated in the post-stimulatory phase of a five minutes lasting equally masking white noise (90 dB HL). Changes of the evoked potentials during adaptation, possible analogy with high tone losses after noise representation and the origin of tinnitus are examined. Stimulation was started 3 sec after the off-effect of the noise. For five minutes periodically tone bursts were represented. Each train of stimulation consists of tone bursts of three frequencies: 2 kcs, 4 kcs, 8 kcs. The 0.5 sec lasting tones were separated by pauses of 2 sec. During the experiment stimulation and analysis were controlled by a computer. Changes in latency and amplitudes of the cortical evoked potentials were registered. Changes of the adaptation patterns as a function of the poststimulatory time are discussed.

Vascular smooth muscle responsiveness to nitric oxide is reduced in healthy adults with increased adiposity

OpenAIRE

Christou, Demetra D.; Pierce, Gary L.; Walker, Ashley E.; Hwang, Moon-Hyon; Yoo, Jeung-Ki; Luttrell, Meredith; Meade, Thomas H.; English, Mark; Seals, Douglas R.

2012-01-01

Vascular smooth muscle responsiveness to nitric oxide, as assessed by nitroglycerin-induced dilation (NID), is impaired in clinical cardiovascular disease, but its relation to adiposity is unknown. We determined the relation of NID to total and abdominal adiposity in healthy adults varying widely in adiposity. In 224 men and women [age, 18–79 years; body mass index (BMI), 16.4–42.2 kg/m2], we measured NID (brachial artery dilation to 0.4 mg sublingual nitroglycerin), total body adiposity [BMI...

Contact Heat Evoked Potentials (CHEPs) in Patients with Mild-Moderate Alzheimer's Disease and Matched Control-A Pilot Study

DEFF Research Database (Denmark)

Jensen-Dahm, Christina; Madsen, Caspar Skau; Waldemar, Gunhild

2016-01-01

OBJECTIVE: Clinical studies have found that patients with Alzheimer's disease report pain of less intensity and with a lower affective response, which has been thought to be due to altered pain processing. The authors wished to examine the cerebral processing of non-painful and painful stimuli...... threshold and heat pain threshold. Somatosensory evoked potentials, amplitude, and latency were within normal range and similar for the two groups. CONCLUSIONS: The findings suggest that the processing of non-painful and painful stimuli is preserved in patients with mild to moderate Alzheimer's disease....... using somatosensory evoked potentials and contact heat evoked potentials in patients with Alzheimer's disease and in healthy elderly controls. DESIGN: Case-control study SETTING AND SUBJECTS: Twenty outpatients with mild-moderate Alzheimer's disease and in 17 age- and gender-matched healthy controls...

Repeated whisker stimulation evokes invariant neuronal responses in the dorsolateral striatum of anesthetized rats: a potential correlate of sensorimotor habits.

Science.gov (United States)

Mowery, Todd M; Harrold, Jon B; Alloway, Kevin D

2011-05-01

The dorsolateral striatum (DLS) receives extensive projections from primary somatosensory cortex (SI), but very few studies have used somesthetic stimulation to characterize the sensory coding properties of DLS neurons. In this study, we used computer-controlled whisker deflections to characterize the extracellular responses of DLS neurons in rats lightly anesthetized with isoflurane. When multiple whiskers were synchronously deflected by rapid back-and-forth movements, whisker-sensitive neurons in the DLS responded to both directions of movement. The latency and magnitude of these neuronal responses displayed very little variation with changes in the rate (2, 5, or 8 Hz) of whisker stimulation. Simultaneous recordings in SI barrel cortex and the DLS revealed important distinctions in the neuronal responses of these serially connected brain regions. In contrast to DLS neurons, SI neurons were activated by the initial deflection of the whiskers but did not respond when the whiskers moved back to their original position. As the rate of whisker stimulation increased, SI responsiveness declined, and the latencies of the responses increased. In fact, when whiskers were deflected at 5 or 8 Hz, many neurons in the DLS responded before the SI neurons. These results and earlier anatomic findings suggest that a component of the sensory-induced response in the DLS is mediated by inputs from the thalamus. Furthermore, the lack of sensory adaptation in the DLS may represent a critical part of the neural mechanism by which the DLS encodes stimulus-response associations that trigger motor habits and other stimulus-evoked behaviors that are not contingent on rewarded outcomes.

Combined ocular and cervical vestibular evoked myogenic potential in individuals with vestibular hyporeflexia and in patients with Ménière's disease.

Science.gov (United States)

Silva, Tatiana Rocha; de Resende, Luciana Macedo; Santos, Marco Aurélio Rocha

The vestibular evoked myogenic potential is a potential of mean latency that measures the muscle response to auditory stimulation. This potential can be generated from the contraction of the sternocleidomastoid muscle and also from the contraction of extraocular muscles in response to high-intensity sounds. This study presents a combined or simultaneous technique of cervical and ocular vestibular evoked myogenic potential in individuals with changes in the vestibular system, for use in otoneurologic diagnosis. To characterize the records and analyze the results of combined cervical and ocular VEMP in individuals with vestibular hyporeflexia and in those with Ménière's disease. The study included 120 subjects: 30 subjects with vestibular hyporeflexia, 30 with Ménière's disease, and 60 individuals with normal hearing. Data collection was performed by simultaneously recording the cervical and ocular vestibular evoked myogenic potential. There were differences between the study groups (individuals with vestibular hyporeflexia and individuals with Ménière's disease) and the control group for most of wave parameters in combined cervical and ocular vestibular evoked myogenic potential. For cervical vestibular evoked myogenic potential, it was observed that the prolongation of latency of the P13 and N23 waves was the most frequent finding in the group with vestibular hyporeflexia and in the group with Ménière's disease. For ocular vestibular evoked myogenic potential, prolonged latency of N10 and P15 waves was the most frequent finding in the study groups. Combined cervical and ocular vestibular evoked myogenic potential presented relevant results for individuals with vestibular hyporeflexia and for those with Ménière's disease. There were differences between the study groups and the control group for most of the wave parameters in combined cervical and ocular vestibular evoked myogenic potential. Copyright © 2016 Associação Brasileira de Otorrinolaringologia

Visually Evoked Spiking Evolves While Spontaneous Ongoing Dynamics Persist

DEFF Research Database (Denmark)

Huys, Raoul; Jirsa, Viktor K; Darokhan, Ziauddin

2016-01-01

attractor. Its existence guarantees that evoked spiking return to the spontaneous state. However, the spontaneous ongoing spiking state and the visual evoked spiking states are qualitatively different and are separated by a threshold (separatrix). The functional advantage of this organization...

Angiogenesis, Cancer, and Vascular Aging

Directory of Open Access Journals (Sweden)

Junji Moriya

2017-10-01

Full Text Available Several lines of evidence have revealed that the angiogenic response to ischemic injury declines with age, which might account for the increased morbidity and mortality of cardiovascular disease (CVD among the elderly. While impairment of angiogenesis with aging leads to delayed wound healing or exacerbation of atherosclerotic ischemic diseases, it also inhibits the progression of cancer. Age-related changes of angiogenesis have been considered to at least partly result from vascular aging or endothelial cell senescence. There is considerable evidence supporting the hypothesis that vascular cell senescence contributes to the pathogenesis of age-related CVD, suggesting that vascular aging could be an important therapeutic target. Since therapeutic angiogenesis is now regarded as a promising concept for patients with ischemic CVD, it has become even more important to understand the detailed molecular mechanisms underlying impairment of angiogenesis in older patients. To improve the usefulness of therapeutic angiogenesis, approaches are needed that can compensate for impaired angiogenic capacity in the elderly while not promoting the development or progression of malignancy. In this review, we briefly outline the mechanisms of angiogenesis and vascular aging, followed by a description of how vascular aging leads to impairment of angiogenesis. We also examine potential therapeutic approaches that could enhance angiogenesis and/or vascular function in the elderly, as well as discussing the possibility of anti-senescence therapy or reversal of endothelial cell senescence.

Joint angle affects volitional and magnetically-evoked neuromuscular performance differentially.

Science.gov (United States)

Minshull, C; Rees, D; Gleeson, N P

2011-08-01

This study examined the volitional and magnetically-evoked neuromuscular performance of the quadriceps femoris at functional knee joint angles adjacent to full extension. Indices of volitional and magnetically-evoked neuromuscular performance (N=15 healthy males, 23.5 ± 2.9 years, 71.5 ± 5.4 kg, 176.5 ± 5.5 cm) were obtained at 25°, 35° and 45° of knee flexion. Results showed that volitional and magnetically-evoked peak force (PF(V) and P(T)F(E), respectively) and electromechanical delay (EMD(V) and EMD(E), respectively) were enhanced by increased knee flexion. However, greater relative improvements in volitional compared to evoked indices of neuromuscular performance were observed with increasing flexion from 25° to 45° (e.g. EMD(V), EMD(E): 36% vs. 11% improvement, respectively; F([2,14])=6.8, pjoint positions. These findings suggest that the extent of the relative differential between volitional and evoked neuromuscular performance capabilities is joint angle-specific and not correlated with performance capabilities at adjacent angles, but tends to be smaller with increased flexion. As such, effective prediction of volitional from evoked performance capabilities at both analogous and adjacent knee joint positions would lack robustness. Copyright © 2011 Elsevier Ltd. All rights reserved.

International Evoked Potentials Symposium

CERN Document Server

1980-01-01

The past decade has seen great progress in the measurement of evoked potentials in man; a steady increase in our understanding of their charac­ teristics, their origins and their usefulness; and a growing application in the field of clinical diagnosis. The topic is a truly multidisciplinary one. Important research contributions have been made by workers of many different backgrounds and clinical applications span the specialities. This book represents a revised and updated version of the work originally presented at the international evoked potential symposium held in Nottingham 4-6 1978. The Nottingham Symposium provided a forum for a state-of-the-art discussion amongst workers from many different disciplines and from many different countries. For each major topic in the field an expert review set the scene for discussion of current research presentations. This format is retained in the book: the chapters in Part A provide the context in which the research presented in Part B is set. The task of selecting m...

Near-infrared spectroscopy assessment of microvasculature detects difference in lower limb vascular responsiveness in obese compared to lean individuals.

Science.gov (United States)

Soares, Rogério Nogueira; Murias, Juan M

2018-07-01

Microvascular dysfunction is an early complication in obesity-related cardiovascular disease (CVD) that can lead to changes in hemodynamic function and endothelial cell expression throughout the vasculature that is vessel specific. This study aimed to evaluate whether the near-infrared spectroscopy (NIRS) combined with a vascular occlusion (VOT) assessment was capable of detecting differences in vascular responsiveness within the microvasculature of the lower limb between lean and obese individuals. Twenty lean (BMI = 21.6 ± 1.3) and 17 obese individuals (BMI = 33.9 ± 1.1) participated in the study. Individuals underwent a VOT (5 min of baseline, 5 min of occlusion, and 8 min following cuff release) and vascular responsiveness was evaluated by the Slope 2 (Slope 2 StO 2 ) and the area under the curve (StO 2AUC ) of oxygen saturation (StO 2 ) signal during reperfusion. The difference between the minimal and the maximal value of StO 2 was calculated as the Amplitude of the StO 2 response. The Slope 2 StO 2 of the obese individuals was smaller (0.68 ± 0.07%·s -1 ) than the Slope 2 StO 2 of the lean individuals (1.08 ± 0.13%·s -1 ;P lean individuals (1708 ± 168%·s -1 ; P lean ones (30.4 ± 2.9 vs 21.6 ± 1.3 StO 2 (%), respectively; P lean individuals (r = 0.745; P lean and obese individuals. Copyright © 2018 Elsevier Inc. All rights reserved.

A new method for registration of kinesthetic evoked potentials for studies of proprioceptive sensitivity in normal subjects and patients with organic lesions in the brain.

Science.gov (United States)

Gordeev, S A; Voronin, S G

2015-01-01

The proprioceptive sensitivity of healthy volunteers and convalescents after acute cerebrovascular episodes was studied by a new neurophysiological method for registration of kinesthetic evoked potentials emerging in response to passive 50(o) bending of the hand in the wrist joint with the angular acceleration of 350 rad/sec(2). Kinesthetic evoked potentials were recorded above the somatosensory cortex projection areas in the hemispheres contra- and ipsilateral to the stimulated limb. The patients exhibited significantly longer latencies and lesser amplitudes of the early components of response in the involved hemisphere in comparison with normal subjects. The method for registration of the kinesthetic evoked potentials allows a more detailed study of the mechanisms of kinesthetic sensitivity in health and in organic involvement of the brain.

A key role for the endothelium in NOD1 mediated vascular inflammation: comparison to TLR4 responses.

Directory of Open Access Journals (Sweden)

Timothy Gatheral

Full Text Available Understanding the mechanisms by which pathogens induce vascular inflammation and dysfunction may reveal novel therapeutic targets in sepsis and related conditions. The intracellular receptor NOD1 recognises peptidoglycan which features in the cell wall of gram negative and some gram positive bacteria. NOD1 engagement generates an inflammatory response via activation of NFκB and MAPK pathways. We have previously shown that stimulation of NOD1 directly activates blood vessels and causes experimental shock in vivo. In this study we have used an ex vivo vessel-organ culture model to characterise the relative contribution of the endothelium in the response of blood vessels to NOD1 agonists. In addition we present the novel finding that NOD1 directly activates human blood vessels. Using human cultured cells we confirm that endothelial cells respond more avidly to NOD1 agonists than vascular smooth muscle cells. Accordingly we have sought to pharmacologically differentiate NOD1 and TLR4 mediated signalling pathways in human endothelial cells, focussing on TAK1, NFκB and p38 MAPK. In addition we profile novel inhibitors of RIP2 and NOD1 itself, which specifically inhibit NOD1 ligand induced inflammatory signalling in the vasculature. This paper is the first to demonstrate activation of whole human artery by NOD1 stimulation and the relative importance of the endothelium in the sensing of NOD1 ligands by vessels. This data supports the potential utility of NOD1 and RIP2 as therapeutic targets in human disease where vascular inflammation is a clinical feature, such as in sepsis and septic shock.

Complicação vascular de osteocondroma: relato de caso Vascular complication of osteochondroma: case report

Directory of Open Access Journals (Sweden)

Fábio André Tornquist

2007-03-01

Full Text Available Osteocondromas ou exostoses são os tumores benignos mais comuns do tecido ósseo. Eles surgem durante o período de crescimento e, raramente, são responsáveis por complicações vasculares. No presente relato, reportamos um caso de paciente com osteocondroma no membro inferior e complicação vascular provocada pela compressão da artéria poplítea. O paciente apresentava queixas de dor em membro inferior direito quando foi investigado com angiografia e radiografia, que identificaram a lesão vascular e a tumoração óssea. Os tratamentos cirúrgicos simultâneos de ambas as lesões foram realizados com boa evolução pós-operatória.Osteochondromas or exostoses are the most common benign tumors of the bone. They occur during the growth period and are rarely responsible for vascular complications. We report a case of a patient with osteochondroma in the lower limb and vascular complication caused by compression of the popliteal artery. The patient complained of pain at the right lower limb during angiography and radiography screening, which identified the vascular lesion and the bone tumor. A simultaneous surgical treatment of both lesions was performed with good postoperative evolution.

Bisensory stimulation increases gamma-responses over multiple cortical regions.

Science.gov (United States)

Sakowitz, O W; Quiroga, R Q; Schürmann, M; Başar, E

2001-04-01

In the framework of the discussion about gamma (approx. 40 Hz) oscillations as information carriers in the brain, we investigated the relationship between gamma responses in the EEG and intersensory association. Auditory evoked potentials (AEPs) and visual evoked potentials (VEPs) were compared with bisensory evoked potentials (BEPs; simultaneous auditory and visual stimulation) in 15 subjects. Gamma responses in AEPs, VEPs and BEPs were assessed by means of wavelet decomposition. Overall maximum gamma-components post-stimulus were highest in BEPs (P < 0.01). Bisensory evoked gamma-responses also showed significant central, parietal and occipital amplitude-increases (P < 0.001, P < 0.01, P < 0.05, respectively; prestimulus interval as baseline). These were of greater magnitude when compared with the unisensory responses. As a correlate of the marked gamma responses to bimodal stimulation we suggest a process of 'intersensory association', i.e. one of the steps between sensory transmission and perception. Our data may be interpreted as a further example of function-related gamma responses in the EEG.

Visually Evoked 3-5 Hz Membrane Potential Oscillations Reduce the Responsiveness of Visual Cortex Neurons in Awake Behaving Mice.

Science.gov (United States)

Einstein, Michael C; Polack, Pierre-Olivier; Tran, Duy T; Golshani, Peyman

2017-05-17

Low-frequency membrane potential ( V m ) oscillations were once thought to only occur in sleeping and anesthetized states. Recently, low-frequency V m oscillations have been described in inactive awake animals, but it is unclear whether they shape sensory processing in neurons and whether they occur during active awake behavioral states. To answer these questions, we performed two-photon guided whole-cell V m recordings from primary visual cortex layer 2/3 excitatory and inhibitory neurons in awake mice during passive visual stimulation and performance of visual and auditory discrimination tasks. We recorded stereotyped 3-5 Hz V m oscillations where the V m baseline hyperpolarized as the V m underwent high amplitude rhythmic fluctuations lasting 1-2 s in duration. When 3-5 Hz V m oscillations coincided with visual cues, excitatory neuron responses to preferred cues were significantly reduced. Despite this disruption to sensory processing, visual cues were critical for evoking 3-5 Hz V m oscillations when animals performed discrimination tasks and passively viewed drifting grating stimuli. Using pupillometry and animal locomotive speed as indicators of arousal, we found that 3-5 Hz oscillations were not restricted to unaroused states and that they occurred equally in aroused and unaroused states. Therefore, low-frequency V m oscillations play a role in shaping sensory processing in visual cortical neurons, even during active wakefulness and decision making. SIGNIFICANCE STATEMENT A neuron's membrane potential ( V m ) strongly shapes how information is processed in sensory cortices of awake animals. Yet, very little is known about how low-frequency V m oscillations influence sensory processing and whether they occur in aroused awake animals. By performing two-photon guided whole-cell recordings from layer 2/3 excitatory and inhibitory neurons in the visual cortex of awake behaving animals, we found visually evoked stereotyped 3-5 Hz V m oscillations that disrupt

Brainstem auditory evoked responses in an equine patient population: part I--adult horses.

Science.gov (United States)

Aleman, M; Holliday, T A; Nieto, J E; Williams, D C

2014-01-01

Brainstem auditory evoked response has been an underused diagnostic modality in horses as evidenced by few reports on the subject. To describe BAER findings, common clinical signs, and causes of hearing loss in adult horses. Study group, 76 horses; control group, 8 horses. Retrospective. BAER records from the Clinical Neurophysiology Laboratory were reviewed from the years of 1982 to 2013. Peak latencies, amplitudes, and interpeak intervals were measured when visible. Horses were grouped under disease categories. Descriptive statistics and a posthoc Bonferroni test were performed. Fifty-seven of 76 horses had BAER deficits. There was no breed or sex predisposition, with the exception of American Paint horses diagnosed with congenital sensorineural deafness. Eighty-six percent (n = 49/57) of the horses were younger than 16 years of age. The most common causes of BAER abnormalities were temporohyoid osteoarthropathy (THO, n = 20/20; abnormalities/total), congenital sensorineural deafness in Paint horses (17/17), multifocal brain disease (13/16), and otitis media/interna (4/4). Auditory loss was bilateral and unilateral in 74% (n = 42/57) and 26% (n = 15/57) of the horses, respectively. The most common causes of bilateral auditory loss were sensorineural deafness, THO, and multifocal brain disease whereas THO and otitis were the most common causes of unilateral deficits. Auditory deficits should be investigated in horses with altered behavior, THO, multifocal brain disease, otitis, and in horses with certain coat and eye color patterns. BAER testing is an objective and noninvasive diagnostic modality to assess auditory function in horses. Copyright © 2014 by the American College of Veterinary Internal Medicine.

Long-term evolution of brainstem electrical evoked responses to sound after restricted ablation of the auditory cortex.

Directory of Open Access Journals (Sweden)

Verónica Lamas

Full Text Available INTRODUCTION: This study aimed to assess the top-down control of sound processing in the auditory brainstem of rats. Short latency evoked responses were analyzed after unilateral or bilateral ablation of auditory cortex. This experimental paradigm was also used towards analyzing the long-term evolution of post-lesion plasticity in the auditory system and its ability to self-repair. METHOD: Auditory cortex lesions were performed in rats by stereotactically guided fine-needle aspiration of the cerebrocortical surface. Auditory Brainstem Responses (ABR were recorded at post-surgery day (PSD 1, 7, 15 and 30. Recordings were performed under closed-field conditions, using click trains at different sound intensity levels, followed by statistical analysis of threshold values and ABR amplitude and latency variables. Subsequently, brains were sectioned and immunostained for GAD and parvalbumin to assess the location and extent of lesions accurately. RESULTS: Alterations in ABR variables depended on the type of lesion and post-surgery time of ABR recordings. Accordingly, bilateral ablations caused a statistically significant increase in thresholds at PSD1 and 7 and a decrease in waves amplitudes at PSD1 that recover at PSD7. No effects on latency were noted at PSD1 and 7, whilst recordings at PSD15 and 30 showed statistically significant decreases in latency. Conversely, unilateral ablations had no effect on auditory thresholds or latencies, while wave amplitudes only decreased at PSD1 strictly in the ipsilateral ear. CONCLUSION: Post-lesion plasticity in the auditory system acts in two time periods: short-term period of decreased sound sensitivity (until PSD7, most likely resulting from axonal degeneration; and a long-term period (up to PSD7, with changes in latency responses and recovery of thresholds and amplitudes values. The cerebral cortex may have a net positive gain on the auditory pathway response to sound.

Auditory evoked potentials to abrupt pitch and timbre change of complex tones: electrophysiological evidence of 'streaming'?

Science.gov (United States)

Jones, S J; Longe, O; Vaz Pato, M

1998-03-01

Examination of the cortical auditory evoked potentials to complex tones changing in pitch and timbre suggests a useful new method for investigating higher auditory processes, in particular those concerned with 'streaming' and auditory object formation. The main conclusions were: (i) the N1 evoked by a sudden change in pitch or timbre was more posteriorly distributed than the N1 at the onset of the tone, indicating at least partial segregation of the neuronal populations responsive to sound onset and spectral change; (ii) the T-complex was consistently larger over the right hemisphere, consistent with clinical and PET evidence for particular involvement of the right temporal lobe in the processing of timbral and musical material; (iii) responses to timbral change were relatively unaffected by increasing the rate of interspersed changes in pitch, suggesting a mechanism for detecting the onset of a new voice in a constantly modulated sound stream; (iv) responses to onset, offset and pitch change of complex tones were relatively unaffected by interfering tones when the latter were of a different timbre, suggesting these responses must be generated subsequent to auditory stream segregation.

Effect of caffeine on vestibular evoked myogenic potential: a systematic review with meta-analysis.

Science.gov (United States)

Souza, Maria Eduarda Di Cavalcanti Alves de; Costa, Klinger Vagner Teixeira da; Menezes, Pedro de Lemos

2017-12-24

Caffeine can be considered the most consumed drug by adults worldwide, and can be found in several foods, such as chocolate, coffee, tea, soda and others. Overall, caffeine in moderate doses, results in increased physical and intellectual productivity, increases the capacity of concentration and reduces the time of reaction to sensory stimuli. On the other hand, high doses can cause noticeable signs of mental confusion and error induction in intellectual tasks, anxiety, restlessness, muscle tremors, tachycardia, labyrinthine changes, and tinnitus. Considering that the vestibular evoked myogenic potential is a clinical test that evaluates the muscular response of high intensity auditory stimulation, the present systematic review aimed to analyze the effects of caffeine on vestibular evoked myogenic potential. This study consisted of the search of the following databases: MEDLINE, CENTRAL, ScienceDirect, Scopus, Web of Science, LILACS, SciELO and ClinicalTrials.gov. Additionally, the gray literature was also searched. The search strategy included terms related to intervention (caffeine or coffee consumption) and the primary outcome (vestibular evoked myogenic potential). Based on the 253 potentially relevant articles identified through the database search, only two full-text publications were retrieved for further evaluation, which were maintained for qualitative analysis. Analyzing the articles found, caffeine has no effect on vestibular evoked myogenic potential in normal individuals. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

White matter damage and glymphatic dysfunction in a model of vascular dementia in rats with no prior vascular pathologies.

Science.gov (United States)

Venkat, Poornima; Chopp, Michael; Zacharek, Alex; Cui, Chengcheng; Zhang, Li; Li, Qingjiang; Lu, Mei; Zhang, Talan; Liu, Amy; Chen, Jieli

2017-02-01

We investigated cognitive function, axonal/white matter (WM) changes and glymphatic function of vascular dementia using a multiple microinfarction (MMI) model in retired breeder (RB) rats. The MMI model induces significant (p rats subjected to MMI exhibit significant axonal/WM damage identified by decreased myelin thickness, oligodendrocyte progenitor cell numbers, axon density, synaptic protein expression in the cortex and striatum, cortical neuronal branching, and dendritic spine density in the cortex and hippocampus compared with age-matched controls. MMI evokes significant dilation of perivascular spaces as well as water channel dysfunction indicated by decreased Aquaporin-4 expression around blood vessels. MMI-induced glymphatic dysfunction with delayed cerebrospinal fluid penetration into the brain parenchyma via paravascular pathways as well as delayed waste clearance from the brain. The MMI model in RB rats decreases Aquaporin-4 and induces glymphatic dysfunction which may play an important role in MMI-induced axonal/WM damage and cognitive deficits. Copyright © 2016 Elsevier Inc. All rights reserved.

Brain correlates of music-evoked emotions.

Science.gov (United States)

Koelsch, Stefan

2014-03-01

Music is a universal feature of human societies, partly owing to its power to evoke strong emotions and influence moods. During the past decade, the investigation of the neural correlates of music-evoked emotions has been invaluable for the understanding of human emotion. Functional neuroimaging studies on music and emotion show that music can modulate activity in brain structures that are known to be crucially involved in emotion, such as the amygdala, nucleus accumbens, hypothalamus, hippocampus, insula, cingulate cortex and orbitofrontal cortex. The potential of music to modulate activity in these structures has important implications for the use of music in the treatment of psychiatric and neurological disorders.

Magnetic resonance imaging of pediatric soft-tissue vascular anomalies

International Nuclear Information System (INIS)

Navarro, Oscar M.

2016-01-01

Magnetic resonance (MR) imaging can be used in the management of pediatric soft-tissue vascular anomalies for diagnosing and assessing extent of lesions and for evaluating response to therapy. MR imaging studies often involve a combination of T1- and T2-weighted images in addition to MR angiography and fat-suppressed post-contrast sequences. The MR imaging features of these vascular anomalies when combined with clinical findings can aid in diagnosis. In cases of complex vascular malformations and syndromes associated with vascular anomalies, MR imaging can be used to evaluate accompanying soft-tissue and bone anomalies. This article reviews the MR imaging protocols and appearances of the most common pediatric soft-tissue vascular anomalies. (orig.)

Simultaneous detection of P300 and steady-state visually evoked potentials for hybrid brain-computer interface.

Science.gov (United States)

Combaz, Adrien; Van Hulle, Marc M

2015-01-01

We study the feasibility of a hybrid Brain-Computer Interface (BCI) combining simultaneous visual oddball and Steady-State Visually Evoked Potential (SSVEP) paradigms, where both types of stimuli are superimposed on a computer screen. Potentially, such a combination could result in a system being able to operate faster than a purely P300-based BCI and encode more targets than a purely SSVEP-based BCI. We analyse the interactions between the brain responses of the two paradigms, and assess the possibility to detect simultaneously the brain activity evoked by both paradigms, in a series of 3 experiments where EEG data are analysed offline. Despite differences in the shape of the P300 response between pure oddball and hybrid condition, we observe that the classification accuracy of this P300 response is not affected by the SSVEP stimulation. We do not observe either any effect of the oddball stimulation on the power of the SSVEP response in the frequency of stimulation. Finally results from the last experiment show the possibility of detecting both types of brain responses simultaneously and suggest not only the feasibility of such hybrid BCI but also a gain over pure oddball- and pure SSVEP-based BCIs in terms of communication rate.

Head movements evoked in alert rhesus monkey by vestibular prosthesis stimulation: implications for postural and gaze stabilization.

Directory of Open Access Journals (Sweden)

Diana E Mitchell

Full Text Available The vestibular system detects motion of the head in space and in turn generates reflexes that are vital for our daily activities. The eye movements produced by the vestibulo-ocular reflex (VOR play an essential role in stabilizing the visual axis (gaze, while vestibulo-spinal reflexes ensure the maintenance of head and body posture. The neuronal pathways from the vestibular periphery to the cervical spinal cord potentially serve a dual role, since they function to stabilize the head relative to inertial space and could thus contribute to gaze (eye-in-head + head-in-space and posture stabilization. To date, however, the functional significance of vestibular-neck pathways in alert primates remains a matter of debate. Here we used a vestibular prosthesis to 1 quantify vestibularly-driven head movements in primates, and 2 assess whether these evoked head movements make a significant contribution to gaze as well as postural stabilization. We stimulated electrodes implanted in the horizontal semicircular canal of alert rhesus monkeys, and measured the head and eye movements evoked during a 100 ms time period for which the contribution of longer latency voluntary inputs to the neck would be minimal. Our results show that prosthetic stimulation evoked significant head movements with latencies consistent with known vestibulo-spinal pathways. Furthermore, while the evoked head movements were substantially smaller than the coincidently evoked eye movements, they made a significant contribution to gaze stabilization, complementing the VOR to ensure that the appropriate gaze response is achieved. We speculate that analogous compensatory head movements will be evoked when implanted prosthetic devices are transitioned to human patients.

Depressão vascular no idoso: resposta ao tratamento antidepressivo associado a inibidor das colinesterases Vascular depression in elderly: response to treatment with antidepressant associated to cholinesterase inhibitor

Directory of Open Access Journals (Sweden)

Ricardo Barcelos

2007-01-01

Full Text Available CONTEXTO: Entre os transtornos neuropsiquiátricos ocasionados por eventos cerebrovasculares, a depressão vascular é pouco diagnosticada por médicos não especialistas, causando aumento da morbimortalidade de pacientes idosos. CASO CLÍNICO: Trata-se de um paciente com 67 anos que apresentou resposta parcial a tratamento com inibidores da recaptura de serotonina e efeitos adversos autonômicos graves com outros antidepressivos. A adição de rivastigmina ao citalopram promoveu sucesso terapêutico, com redução de 23 para 7 pontos, na escala de Hamilton para depressão. DISCUSSÃO: O resultado obtido traz novas perspectivas para o tratamento da depressão vascular, sendo necessários ensaios clínicos controlados que evidenciem o benefício da adição dos inibidores das colinesterases aos antidepressivos no tratamento destes pacientes.CONTEXT: Among neuropsychiatric disorders caused by cerebrovascular factors, vascular depression is diagnosed in a small degree by general practitioners, causing morbid-mortality increase in elderly. CASE REPORT: That is a case of a 67 year-old-man with partial response after treatment with a Selective Serotonin Receptors Inhibitor, and severe autonomic adverse effects with other antidepressants. The addition of rivastigmine to citalopram resulted in a therapeutic success, with a reduction of 23 to 7 points on the Hamilton Depressive Scale (HAM-D. DISCUSSION: The result obtained brings new perspectives to the treatment of vascular depression, providing that randomized controlled trials with larger sample sizes confirm the positive effect of the addition of a cholinesterase inhibitor to antidepressants in the treatment of these patients.

An inventory and update of jealousy-evoking partner behaviours in modern society.

NARCIS (Netherlands)

Dijkstra, Pieternel; Barelds, Dick P. H.; Groothof, Hinke A. K.

2010-01-01

The goal of the present study was to identify the most important jealousy-evoking partner behaviours and to examine the extent to which these behaviours evoke jealousy. Based on the literature, a questionnaire was constructed containing 42 jealousy-evoking partner behaviours, including a partner's

CHAPTER 1

African Journals Online (AJOL)

Dr Olaleye

Official Publication of the African Association of Physiological Sciences ... noradrenaline (NA)-evoked vascular responses in carotid circulation in rats. Furthermore, whether the .... PowerLab/8S at 100 Hz and connected to a computer by Chart ...

Synaptically evoked glutamate transporter currents in Spinal Dorsal Horn Astrocytes

Directory of Open Access Journals (Sweden)

Dougherty Patrick M

2009-07-01

Full Text Available Abstract Background Removing and sequestering synaptically released glutamate from the extracellular space is carried out by specific plasma membrane transporters that are primarily located in astrocytes. Glial glutamate transporter function can be monitored by recording the currents that are produced by co-transportation of Na+ ions with the uptake of glutamate. The goal of this study was to characterize glutamate transporter function in astrocytes of the spinal cord dorsal horn in real time by recording synaptically evoked glutamate transporter currents. Results Whole-cell patch clamp recordings were obtained from astrocytes in the spinal substantia gelatinosa (SG area in spinal slices of young adult rats. Glutamate transporter currents were evoked in these cells by electrical stimulation at the spinal dorsal root entry zone in the presence of bicuculline, strychnine, DNQX and D-AP5. Transporter currents were abolished when synaptic transmission was blocked by TTX or Cd2+. Pharmacological studies identified two subtypes of glutamate transporters in spinal astrocytes, GLAST and GLT-1. Glutamate transporter currents were graded with stimulus intensity, reaching peak responses at 4 to 5 times activation threshold, but were reduced following low-frequency (0.1 – 1 Hz repetitive stimulation. Conclusion These results suggest that glutamate transporters of spinal astrocytes could be activated by synaptic activation, and recording glutamate transporter currents may provide a means of examining the real time physiological responses of glial cells in spinal sensory processing, sensitization, hyperalgesia and chronic pain.

Quantification of the proportion of motor neurons recruited by transcranial electrical stimulation during intraoperative motor evoked potential monitoring.

Science.gov (United States)

Tsutsui, Shunji; Yamada, Hiroshi; Hashizume, Hiroshi; Minamide, Akihito; Nakagawa, Yukihiro; Iwasaki, Hiroshi; Yoshida, Munehito

2013-12-01

Transcranial motor evoked potentials (TcMEPs) are widely used to monitor motor function during spinal surgery. However, they are much smaller and more variable in amplitude than responses evoked by maximal peripheral nerve stimulation, suggesting that a limited number of spinal motor neurons to the target muscle are excited by transcranial stimulation. The aim of this study was to quantify the proportion of motor neurons recruited during TcMEP monitoring under general anesthesia. In twenty patients who underwent thoracic and/or lumbar spinal surgery with TcMEP monitoring, the triple stimulation technique (TST) was applied to the unilateral upper arm intraoperatively. Total intravenous anesthesia was employed. Trains of four stimuli were delivered with maximal intensity and an inter-pulse interval of 1.5 ms. TST responses were recorded from the abductor digiti minimi muscle, and the negative peak amplitude and area were measured and compared between the TST test (two collisions between transcranial and proximal and distal peripheral stimulation) and control response (two collisions between two proximal and one distal peripheral stimulation). The highest degree of superimposition of the TST test and control responses was chosen from several trials per patient. The average ratios (test:control) were 17.1 % (range 1.8-38 %) for the amplitudes and 21.6 % (range 2.9-40 %) for the areas. The activity of approximately 80 % of the motor units to the target muscle cannot be detected by TcMEP monitoring. Therefore, changes in evoked potentials must be interpreted cautiously when assessing segmental motor function with TcMEP monitoring.

Sensory-Evoked Intrinsic Imaging Signals in the Olfactory Bulb Are Independent of Neurovascular Coupling

Directory of Open Access Journals (Sweden)

Roberto Vincis

2015-07-01

Full Text Available Functional brain-imaging techniques used in humans and animals, such as functional MRI and intrinsic optical signal (IOS imaging, are thought to largely rely on neurovascular coupling and hemodynamic responses. Here, taking advantage of the well-described micro-architecture of the mouse olfactory bulb, we dissected the nature of odor-evoked IOSs. Using in vivo pharmacology in transgenic mouse lines reporting activity in different cell types, we show that parenchymal IOSs are largely independent of neurotransmitter release and neurovascular coupling. Furthermore, our results suggest that odor-evoked parenchymal IOSs originate from changes in light scattering of olfactory sensory neuron axons, mostly due to water movement following action potential propagation. Our study sheds light on a direct correlate of neuronal activity, which may be used for large-scale functional brain imaging.

Short-interval and long-interval intracortical inhibition of TMS-evoked EEG potentials.

Science.gov (United States)

Premoli, Isabella; Király, Julia; Müller-Dahlhaus, Florian; Zipser, Carl M; Rossini, Pierre; Zrenner, Christoph; Ziemann, Ulf; Belardinelli, Paolo

2018-03-15

Inhibition in the human motor cortex can be probed by means of paired-pulse transcranial magnetic stimulation (ppTMS) at interstimulus intervals of 2-3 ms (short-interval intracortical inhibition, SICI) or ∼100 ms (long-interval intracortical inhibition, LICI). Conventionally, SICI and LICI are recorded as motor evoked potential (MEP) inhibition in the hand muscle. Pharmacological experiments indicate that they are mediated by GABAA and GABAB receptors, respectively. SICI and LICI of TMS-evoked EEG potentials (TEPs) and their pharmacological properties have not been systematically studied. Here, we sought to examine SICI by ppTMS-evoked compared to single-pulse TMS-evoked TEPs, to investigate its pharmacological manipulation and to compare SICI with our previous results on LICI. PpTMS-EEG was applied to the left motor cortex in 16 healthy subjects in a randomized, double-blind placebo-controlled crossover design, testing the effects of a single oral dose 20 mg of diazepam, a positive modulator at the GABAA receptor, vs. 50 mg of the GABAB receptor agonist baclofen on SICI of TEPs. We found significant SICI of the N100 and P180 TEPs prior to drug intake. Diazepam reduced SICI of the N100 TEP, while baclofen enhanced it. Compared to our previous ppTMS-EEG results on LICI, the SICI effects on TEPs, including their drug modulation, were largely analogous. Findings suggest a similar interaction of paired-pulse effects on TEPs irrespective of the interstimulus interval. Therefore, SICI and LICI as measured with TEPs cannot be directly derived from SICI and LICI measured with MEPs, but may offer novel insight into paired-pulse responses recorded directly from the brain rather than muscle. Copyright © 2018 Elsevier Inc. All rights reserved.

Experimental study on the vascular thermal response to visible laser pulses.

Science.gov (United States)

Li, D; Chen, B; Wu, W J; Wang, G X; He, Y L; Ying, Z X

2015-01-01

Port-wine stains (PWSs) are congenital vascular malformations that progressively darken and thicken with age, and laser therapy is the most effective in clinical practice. Using dorsal skin chamber (DSC), this study evaluated thermal response of blood vessel to a 595-nm pulsed dye laser (PDL) with controlled energy doses and pulse durations. Totally, 32 vessels (30∼300 μm in diameter) are selected from the dorsal skin of the mouse to match those in port-wine stain. The experimental results showed that the thermal response of the blood vessels to laser irradiation can be recognized as coagulation, constriction with diameter decrease, disappearance (complete constriction), hemorrhage, and collagen damage in the order of increasing laser radiant exposure. Blood vessels with small diameter would response poorly and survive from the laser heating because their thermal relaxation time is much shorter than the pulse duration. The optimalradiant exposure is from 10 to 12 J/cm(2) under 6 ms pulse duration without considering the epidermal light absorption. Numerical simulations were also conducted using a 1,000-μm deep Sprague-Dawley (SD) mouse skinfold. The light transportation and heat diffusion in dorsal skin were simulated with the Monte Carlo method and heat transfer equation, while the blood vessel photocoagulation was evaluated by Arrhenius-type kinetic integral. Both experimental observation and numerical simulation supported that hemorrhage is the dominant thermal response, which occurs due to preferential heating of the superior parts of large blood vessels. In clinical practice for 595 nm PDL, the consequent purpura caused by hemorrhage can be used as a treatment end point.

Music-evoked emotions: principles, brain correlates, and implications for therapy.

Science.gov (United States)

Koelsch, Stefan

2015-03-01

This paper describes principles underlying the evocation of emotion with music: evaluation, resonance, memory, expectancy/tension, imagination, understanding, and social functions. Each of these principles includes several subprinciples, and the framework on music-evoked emotions emerging from these principles and subprinciples is supposed to provide a starting point for a systematic, coherent, and comprehensive theory on music-evoked emotions that considers both reception and production of music, as well as the relevance of emotion-evoking principles for music therapy. © 2015 New York Academy of Sciences.

Ocular vestibular evoked myogenic potential in patients with benign paroxysmal positional vertigo

Directory of Open Access Journals (Sweden)

Mozhgan Masoom

2014-06-01

Full Text Available Background and Aim: Since utricle is the main damaged organ in benign paroxysmal positional vertigo (BPPV, ocular vestibular evoked myogenic potential (oVEMP may be an appropriate method to evaluate the utricule dysfunction and the effect of disease recurrence rate on it. This study aimed to record myogenic potential in patients with benign paroxysmal positional vertigo.Methods: In a cross-sectional study, ocular myogenic potential was recorded in 25 healthy subjects and 20 patients with benign paroxysmal positional vertigo using 500 Hz-tone bursts (95 dB nHL.Results: In the affected ear, mean amplitude was lower and mean threshold was higher than those in the unaffected ear and in the normal group (p<0.05. Mean amplitude asymmetry ratio of patients was more than the healthy subjects (p0.05. Frequencies of abnormal responses in the affected ears were higher than in unaffected ears and in the normal group (p<0.05. Furthermore, the patients with recurrent vertigo showed more abnormalities than the patients with non-recurrent (p=0.030.Conclusion: In the recurrent benign paroxysmal positional vertigo, ocular vestibular evoked myogenic potential showed more damage in the utricle, suggesting this response could be used to evaluate the patients with benign paroxysmal positional vertigo.

Lower limb vascular dysfunction in cyclists

Directory of Open Access Journals (Sweden)

Thiago Ayala Melo Di Alencar

2013-06-01

Full Text Available Sports-related vascular insufficiency affecting the lower limbs is uncommon, and early signs and symptoms can be confused with musculoskeletal injuries. This is also the case among professional cyclists, who are always at the threshold between endurance and excess training. The aim of this review was to analyze the occurrence of vascular disorders in the lower limbs of cyclists and to discuss possible etiologies. Eighty-five texts, including papers and books, published from 1950 to 2012, were used. According to the literature reviewed, some cyclists receive a late diagnosis of vascular dysfunction due to a lack of familiarity of the medical team with this type of dysfunction. Data revealed that a reduced blood flow in the external iliac artery, especially on the left, is much more common than in the femoral and popliteal arteries, and that vascular impairment is responsible for the occurrence of early fatigue and reduced performance in cycling.

Structural and functional imaging for vascular targeted photodynamic therapy

Science.gov (United States)

Li, Buhong; Gu, Ying; Wilson, Brian C.

2017-02-01

Vascular targeted photodynamic therapy (V-PDT) has been widely used for the prevention or treatment of vascular-related diseases, such as localized prostate cancer, wet age-related macular degeneration, port wine stains, esophageal varices and bleeding gastrointestinal mucosal lesions. In this study, the fundamental mechanisms of vascular responses during and after V-PDT will be introduced. Based on the V-PDT treatment of blood vessels in dorsal skinfold window chamber model, the structural and functional imaging, which including white light microscopy, laser speckle imaging, singlet oxygen luminescence imaging, and fluorescence imaging for evaluating vascular damage will be presented, respectively. The results indicate that vessel constriction and blood flow dynamics could be considered as the crucial biomarkers for quantitative evaluation of vascular damage. In addition, future perspectives of non-invasive optical imaging for evaluating vascular damage of V-PDT will be discussed.

The involuntary nature of music-evoked autobiographical memories in Alzheimer's disease.

Science.gov (United States)

El Haj, Mohamad; Fasotti, Luciano; Allain, Philippe

2012-03-01

The main objective of this paper was to examine the involuntary nature of music-evoked autobiographical memories. For this purpose, young adults, older adults, and patients with a clinical diagnosis of probable Alzheimer's disease (AD) were asked to remember autobiographical events in two conditions: after being exposed to their own chosen music, and in silence. Compared to memories evoked in silence, memories evoked in the "Music" condition were found to be more specific, accompanied by more emotional content and impact on mood, and retrieved faster. In addition, these memories engaged less executive processes. Thus, with all these characteristics and the fact that they are activated by a perceptual cue (i.e., music), music-evoked autobiographic memories have all the features to be considered as involuntary memories. Our paper reveals several characteristics of music-evoked autobiographical memories in AD patients and offers a theoretical background for this phenomenon. Copyright © 2012 Elsevier Inc. All rights reserved.

Membrane permeable C-terminal dopamine transporter peptides attenuate amphetamine-evoked dopamine release

DEFF Research Database (Denmark)

Rickhag, Karl Mattias; Owens, WA; Winkler, Marie-Therese

2013-01-01

The dopamine transporter (DAT) is responsible for sequestration of extracellular dopamine (DA). The psychostimulant amphetamine (AMPH) is a DAT substrate, which is actively transported into the nerve terminal, eliciting vesicular depletion and reversal of DA transport via DAT. Here, we investigate......-terminal protein-protein interactions are critical for AMPH-evoked DA efflux and suggest that it may be possible to target protein-protein interactions to modulate transporter function and interfere with psychostimulant effects....

DCE-MRI-Derived Parameters in Evaluating Abraxane-Induced Early Vascular Response and the Effectiveness of Its Synergistic Interaction with Cisplatin.

Directory of Open Access Journals (Sweden)

Xilin Sun

Full Text Available Our previous studies revealed molecular alterations of tumor vessels, varying from immature to mature alterations, resulting from Abraxane, and demonstrated that the integrin-specific PET tracer 18F-FPPRGD2 can be used to noninvasively monitor such changes. However, changes in the tumor vasculature at functional levels such as perfusion and permeability are also important for monitoring Abraxane treatment outcomes in patients with cancer. The purpose of this study is to further investigate the vascular response during Abraxane therapy and the effectiveness of its synergistic interaction with cisplatin using Dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI. Thirty MDA-MB-435 tumor mice were randomized into three groups: PBS control (C group, Abraxane only (A group, and sequential treatment with Abraxane followed by cisplatin (A-P group. Tumor volume was monitored based on caliper measurements. A DCE-MRI protocol was performed at baseline and day 3. The Ktrans, Kep and Ve were calculated and compared with CD31, α-SMA, and Ki67 histology data. Sequential treatment with Abraxane followed by cisplatin produced a significantly greater inhibition of tumor growth during the three weeks of the observation period. Decreases in Ktrans and Kep for the A and A-P groups were observed on day 3. Immunohistological staining suggested vascular remodeling during the Abraxane therapy. The changes in Ktrans and Kep values were correlated with alterations in the permeability of the tumor vasculature induced by the Abraxane treatment. In conclusion, Abraxane-mediated permeability variations in tumor vasculature can be quantitatively visualized by DCE-MRI, making this a useful method for studying the effects of early cancer treatment, especially the early vascular response. Vascular remodeling by Abraxane improves the efficiency of cisplatin delivery and thus results in a favorable treatment outcome.

Three-dimensional reconstruction of port wine stain vascular anatomy from serial histological sections

NARCIS (Netherlands)

Smithies, D. J.; van Gemert, M. J.; Hansen, M. K.; Milner, T. E.; Nelson, J. S.

1997-01-01

Port wine stains (PWSs) treated with a flashlamp-pumped pulsed dye laser show a variability in clinical response that is incompletely understood. To identify any vascular structure that might adversely affect treatment response, we obtained a three-dimensional reconstruction of the vascular anatomy

Vascular Response to Intra-arterial Injury in the Thrombospondin-1 Null Mouse

OpenAIRE

Budhani, Faisal; Leonard, Katherine A.; Bergdahl, Andreas; Gao, Jimin; Lawler, Jack; Davis, Elaine C.

2007-01-01

Thrombospondin-1 (TSP-1) is a multifunctional, extracellular matrix protein that has been implicated in the regulation of smooth muscle cell proliferation, migration and differentiation during vascular development and injury. Vascular injury in wildtype and TSP-1 null mice was carried out by insertion of a straight spring guidewire into the femoral artery via a muscular arterial branch. Blood flow was restored after the muscular branch was ligated. The injury completely denuded the endotheliu...

Molecular mechanisms of maternal vascular dysfunction in preeclampsia.

Science.gov (United States)

Goulopoulou, Styliani; Davidge, Sandra T

2015-02-01

In preeclampsia, as a heterogeneous syndrome, multiple pathways have been proposed for both the causal as well as the perpetuating factors leading to maternal vascular dysfunction. Postulated mechanisms include imbalance in the bioavailability and activity of endothelium-derived contracting and relaxing factors and oxidative stress. Studies have shown that placenta-derived factors [antiangiogenic factors, microparticles (MPs), cell-free nucleic acids] are released into the maternal circulation and act on the vascular wall to modify the secretory capacity of endothelial cells and alter the responsiveness of vascular smooth muscle cells to constricting and relaxing stimuli. These molecules signal their deleterious effects on the maternal vascular wall via pathways that provide the molecular basis for novel and effective therapeutic interventions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Relationship between median nerve somatosensory evoked potentials and spinal cord injury levels in patients with quadriplegia.

Science.gov (United States)

de Arruda Serra Gaspar, M I F; Cliquet, A; Fernandes Lima, V M; de Abreu, D C C

2009-05-01

Cross-sectional study. To observe if there is a relationship between the level of injury by the American Spinal Cord Injury Association (ASIA) and cortical somatosensory evoked potential (SSEP) recordings of the median nerve in patients with quadriplegia. Rehabilitation Outpatient Clinic at the university hospital in Brazil. Fourteen individuals with quadriplegia and 8 healthy individuals were evaluated. Electrophysiological assessment of the median nerve was performed by evoked potential equipment. The injury level was obtained by ASIA. N(9), N(13) and N(20) were analyzed based on the presence or absence of responses. The parameters used for analyzing these responses were the latency and the amplitude. Data were analyzed using mixed-effect models. N(9) responses were found in all patients with quadriplegia with a similar latency and amplitude observed in healthy individuals; N(13) responses were not found in any patients with quadriplegia. N(20) responses were not found in C5 patients with quadriplegia but it was present in C6 and C7 patients. Their latencies were similar to healthy individuals (P>0.05) but the amplitudes were decreased (P<0.05). This study suggests that the SSEP responses depend on the injury level, considering that the individuals with C6 and C7 injury levels, both complete and incomplete, presented SSEP recordings in the cortical area. It also showed a relationship between the level of spinal cord injury assessed by ASIA and the median nerve SSEP responses, through the latency and amplitude recordings.

Vascular Gene Expression: A Hypothesis

Directory of Open Access Journals (Sweden)

Angélica Concepción eMartínez-Navarro

2013-07-01

Full Text Available The phloem is the conduit through which photoassimilates are distributed from autotrophic to heterotrophic tissues and is involved in the distribution of signaling molecules that coordinate plant growth and responses to the environment. Phloem function depends on the coordinate expression of a large array of genes. We have previously identified conserved motifs in upstream regions of the Arabidopsis genes, encoding the homologs of pumpkin phloem sap mRNAs, displaying expression in vascular tissues. This tissue-specific expression in Arabidopsis is predicted by the overrepresentation of GA/CT-rich motifs in gene promoters. In this work we have searched for common motifs in upstream regions of the homologous genes from plants considered to possess a primitive vascular tissue (a lycophyte, as well as from others that lack a true vascular tissue (a bryophyte, and finally from chlorophytes. Both lycophyte and bryophyte display motifs similar to those found in Arabidopsis with a significantly low E-value, while the chlorophytes showed either a different conserved motif or no conserved motif at all. These results suggest that these same genes are expressed coordinately in non- vascular plants; this coordinate expression may have been one of the prerequisites for the development of conducting tissues in plants. We have also analyzed the phylogeny of conserved proteins that may be involved in phloem function and development. The presence of CmPP16, APL, FT and YDA in chlorophytes suggests the recruitment of ancient regulatory networks for the development of the vascular tissue during evolution while OPS is a novel protein specific to vascular plants.

Vestibular Evoked Myogenic Potential Produced by Bone-Conducted Stimuli: A Study on its Basics and Clinical Applications in Patients with Conductive and Sensorineural Hearing Loss and a Group with Vestibular Schawannoma.

Science.gov (United States)

Mahdi, Parvane; Amali, Amin; Pourbakht, Akram; Karimi Yazdi, Alireza; Bassam, Ali

2013-06-01

Vestibular evoked myogenic potential (VEMP) has recently been broadly studied in vestibular disorders. As it is evoked by loud sound stimulation, even mild conductive hearing loss may affect VEMP results. Bone-conducted (BC) stimulus is an alternative stimulation for evoking this response. This study aims to assess the characteristics of BC-VEMP in different groups of patients. We performed a cross sectional analysis on 20 healthy volunteers with normal pure-tone audiometry as a control group; and on a group of patients consisted of 20 participants with conductive hearing loss, five with bilateral sensorineural hearing loss and four with vestibular schawannoma. AC and BC-VEMP were performed in all participants. In control group the VEMP responses to both kinds of stimuli had an acceptable morphology and consisted of p13 and n23 waves. Latency value of these main components in each type of stimulus was not significantly different (P>0.05). However, the mean amplitude was larger in BC modality than AC stimulation (P=0.025). In the group with conductive hearing loss, the VEMP response was absent in fifteen (46.87%) of the 32 ears using the AC method, whereas all (100%) displayed positive elicitability of VEMP by BC method. Normal VEMP responses in both stimuli were evoked in all patients with sensorineural hearing loss. In patients with unilateral vestibular schwannomas (VS), 2 (50.00%) had neither AC-VEMP nor BC-VEMP. Auditory stimuli delivered by bone conduction can evoke VEMP response. These responses are of vestibular origin and can be used in vestibular evaluation of patients with conductive hearing loss.

Use of the novel contact heat evoked potential stimulator (CHEPS for the assessment of small fibre neuropathy: correlations with skin flare responses and intra-epidermal nerve fibre counts

Directory of Open Access Journals (Sweden)

Chizh Boris A

2007-08-01

Full Text Available Abstract Background The Contact Heat Evoked Potential Stimulator (CHEPS rapidly stimulates cutaneous small nerve fibres, and resulting evoked potentials can be recorded from the scalp. We have studied patients with symptoms of sensory neuropathy and controls using CHEPS, and validated the findings using other objective measures of small nerve fibres i.e. the histamine-induced skin flare response and intra-epidermal fibres (IEF, and also quantitative sensory testing (QST, a subjective measure. Methods In patients with symptoms of sensory neuropathy (n = 41 and healthy controls (n = 9 we performed clinical examination, QST (monofilament, vibration and thermal perception thresholds, nerve conduction studies, histamine-induced skin flares and CHEPS. Skin punch biopsies were immunostained using standard ABC immunoperoxidase for the nerve marker PGP 9.5 or the heat and capsaicin receptor TRPV1. Immunoreactive IEF were counted per length of tissue section and epidermal thickness recorded. Results Amplitudes of Aδ evoked potentials (μV following face, arm or leg stimulation were reduced in patients (e.g. for the leg: mean ± SEM – controls 11.7 ± 1.95, patients 3.63 ± 0.85, p = 0.0032. Patients showed reduced leg skin flare responses, which correlated with Aδ amplitudes (rs = 0.40, p = 0.010. In patient leg skin biopsies, PGP 9.5- and TRPV1-immunoreactive IEF were reduced and correlated with Aδ amplitudes (PGP 9.5, rs = 0.51, p = 0.0006; TRPV1, rs = 0.48, p = 0.0012. Conclusion CHEPS appears a sensitive measure, with abnormalities observed in some symptomatic patients who did not have significant IEF loss and/or QST abnormalities. Some of the latter patients may have early small fibre dysfunction or ion channelopathy. CHEPS provides a clinically practical, non-invasive and objective measure, and can be a useful additional tool for the assessment of sensory small fibre neuropathy. Although further evaluation is required, the technique shows

Nano- and microstructured materials for in vitro studies of the physiology of vascular cells

Directory of Open Access Journals (Sweden)

Alexandra M. Greiner

2016-11-01

Full Text Available The extracellular environment of vascular cells in vivo is complex in its chemical composition, physical properties, and architecture. Consequently, it has been a great challenge to study vascular cell responses in vitro, either to understand their interaction with their native environment or to investigate their interaction with artificial structures such as implant surfaces. New procedures and techniques from materials science to fabricate bio-scaffolds and surfaces have enabled novel studies of vascular cell responses under well-defined, controllable culture conditions. These advancements are paving the way for a deeper understanding of vascular cell biology and materials–cell interaction. Here, we review previous work focusing on the interaction of vascular smooth muscle cells (SMCs and endothelial cells (ECs with materials having micro- and nanostructured surfaces. We summarize fabrication techniques for surface topographies, materials, geometries, biochemical functionalization, and mechanical properties of such materials. Furthermore, various studies on vascular cell behavior and their biological responses to micro- and nanostructured surfaces are reviewed. Emphasis is given to studies of cell morphology and motility, cell proliferation, the cytoskeleton and cell-matrix adhesions, and signal transduction pathways of vascular cells. We finalize with a short outlook on potential interesting future studies.

DEPTOR regulates vascular endothelial cell activation and proinflammatory and angiogenic responses.

Science.gov (United States)

Bruneau, Sarah; Nakayama, Hironao; Woda, Craig B; Flynn, Evelyn A; Briscoe, David M

2013-09-05

The maintenance of normal tissue homeostasis and the prevention of chronic inflammatory disease are dependent on the active process of inflammation resolution. In endothelial cells (ECs), proinflammation results from the activation of intracellular signaling responses and/or the inhibition of endogenous regulatory/pro-resolution signaling networks that, to date, are poorly defined. In this study, we find that DEP domain containing mTOR interacting protein (DEPTOR) is expressed in different microvascular ECs in vitro and in vivo, and using a small interfering RNA (siRNA) knockdown approach, we find that it regulates mammalian target of rapamycin complex 1 (mTORC1), extracellular signal-regulated kinase 1/2, and signal transducer and activator of transcription 1 activation in part through independent mechanisms. Moreover, using limited gene arrays, we observed that DEPTOR regulates EC activation including mRNA expression of the T-cell chemoattractant chemokines CXCL9, CXCL10, CXCL11, CX3CL1, CCL5, and CCL20 and the adhesion molecules intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 (P < .05). DEPTOR siRNA-transfected ECs also bound increased numbers of peripheral blood mononuclear cells (P < .005) and CD3+ T cells (P < .005) in adhesion assays in vitro and had increased migration and angiogenic responses in spheroid sprouting (P < .01) and wound healing (P < .01) assays. Collectively, these findings define DEPTOR as a critical upstream regulator of EC activation responses and suggest that it plays an important role in endogenous mechanisms of anti-inflammation and pro-resolution.

Bradykinin Contributes to Sympathetic and Pressor Responses Evoked by Activation of Skeletal Muscle Afferents P2X in Heart Failure

Directory of Open Access Journals (Sweden)

Jihong Xing

2016-11-01

Full Text Available Background/Aims: Published data suggest that purinergic P2X receptors of muscle afferent nerves contribute to the enhanced sympathetic nervous activity (SNA and blood pressure (BP responses during static exercise in heart failure (HF. In this study, we examined engagement of bradykinin (BK in regulating responses of SNA and BP evoked by P2X stimulation in rats with HF. We further examined cellular mechanisms responsible for BK. We hypothesized that BK potentiates P2X currents of muscle dorsal root ganglion (DRG neurons, and this effect is greater in HF due to upregulation of BK kinin B2 and P2X3 receptor. As a result, BK amplifies muscle afferents P2X-mediated SNA and BP responses. Methods: Renal SNA and BP responses were recorded in control rats and rats with HF. Western Blot analysis and patch-clamp methods were employed to examine the receptor expression and function of DRG neurons involved in the effects of BK. Results: BK injected into the arterial blood supply of the hindlimb muscles heightened the reflex SNA and BP responses induced by P2X activation with α,β-methylene ATP to a greater degree in HF rats. In addition, HF upregulated the protein expression of kinin B2 and P2X3 in DRG and the prior application of BK increased the magnitude of α,β-methylene ATP-induced currents in muscle DRG neurons from HF rats. Conclusion: BK plays a facilitating role in modulating muscle afferent P2X-engaged reflex sympathetic and pressor responses. In HF, P2X responsivness is augmented due to increases in expression of kinin B2 and P2X3 receptors and P2X current activity.

Major Vascular Neurocognitive Disorder: A Reappraisal to Vascular Dementia

Directory of Open Access Journals (Sweden)

Emre Kumral

2017-03-01

Full Text Available Major vascular neurocognitive disorder (NCD is the second leading form of dementia after Alzheimer’s disease, accounting for 17-20% of all dementias. Vascular NCD is a progressive disease caused by reduced cerebral blood flow related to multiple large volume or lacunar infarcts that induce a sudden onset and stepwise decline in cognitive abilities. Despite its prevalence and clinical importance, there is still controversy in the terminology of vascular NCD. Only after the release of Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5 (2013 did the American Psychiatric Association define vascular dementia as “major vascular NCD”. This review includes an overview of risk factors, pathophysiology, types, diagnostic and clinical features of major vascular NCD, and current treatment options of vascular NCD regarding to DSM-5 criteria

The adventitia: Essential role in pulmonary vascular remodeling.

Science.gov (United States)

Stenmark, Kurt R; Nozik-Grayck, Eva; Gerasimovskaya, Evgenia; Anwar, Adil; Li, Min; Riddle, Suzette; Frid, Maria

2011-01-01

A rapidly emerging concept is that the vascular adventitia acts as a biological processing center for the retrieval, integration, storage, and release of key regulators of vessel wall function. It is the most complex compartment of the vessel wall and comprises a variety of cells including fibroblasts, immunomodulatory cells, resident progenitor cells, vasa vasorum endothelial cells, and adrenergic nerves. In response to vascular stress or injury, resident adventitial cells are often the first to be activated and reprogrammed to then influence tone and structure of the vessel wall. Experimental data indicate that the adventitial fibroblast, the most abundant cellular constituent of adventitia, is a critical regulator of vascular wall function. In response to vascular stresses such as overdistension, hypoxia, or infection, the adventitial fibroblast is activated and undergoes phenotypic changes that include proliferation, differentiation, and production of extracellular matrix proteins and adhesion molecules, release of reactive oxygen species, chemokines, cytokines, growth factors, and metalloproteinases that, collectively, affect medial smooth muscle cell tone and growth directly and that stimulate recruitment and retention of circulating inflammatory and progenitor cells to the vessel wall. Resident dendritic cells also participate in "sensing" vascular stress and actively communicate with fibroblasts and progenitor cells to simulate repair processes that involve expansion of the vasa vasorum, which acts as a conduit for further delivery of inflammatory/progenitor cells. This review presents the current evidence demonstrating that the adventitia acts as a key regulator of pulmonary vascular wall function and structure from the "outside in." © 2011 American Physiological Society.

Characterisation of the p53-mediated cellular responses evoked in primary mouse cells following exposure to ultraviolet radiation.

Directory of Open Access Journals (Sweden)

Gillian D McFeat

Full Text Available Exposure to ultraviolet (UV light can cause significant damage to mammalian cells and, although the spectrum of damage produced varies with the wavelength of UV, all parts of the UV spectrum are recognised as being detrimental to human health. Characterising the cellular response to different wavelengths of UV therefore remains an important aim so that risks and their moderation can be evaluated, in particular in relation to the initiation of skin cancer. The p53 tumour suppressor protein is central to the cellular response that protects the genome from damage by external agents such as UV, thus reducing the risk of tumorigenesis. In response to a variety of DNA damaging agents including UV light, wild-type p53 plays a role in mediating cell-cycle arrest, facilitating apoptosis and stimulating repair processes, all of which prevent the propagation of potentially mutagenic defects. In this study we examined the induction of p53 protein and its influence on the survival of primary mouse fibroblasts exposed to different wavelengths of UV light. UVC was found to elevate p53 protein and its sequence specific DNA binding capacity. Unexpectedly, UVA treatment failed to induce p53 protein accumulation or sequence specific DNA binding. Despite this, UVA exposure of wild-type cells induced a p53 dependent G1 cell cycle arrest followed by a wave of p53 dependent apoptosis, peaking 12 hours post-insult. Thus, it is demonstrated that the elements of the p53 cellular response evoked by exposure to UV radiation are wavelength dependent. Furthermore, the interrelationship between various endpoints is complex and not easily predictable. This has important implications not only for understanding the mode of action of p53 but also for the use of molecular endpoints in quantifying exposure to different wavelengths of UV in the context of human health protection.

A NOS1 variant implicated in cognitive performance influences evoked neural responses during a high density EEG study of early visual perception.

Science.gov (United States)

O'Donoghue, Therese; Morris, Derek W; Fahey, Ciara; Da Costa, Andreia; Foxe, John J; Hoerold, Doreen; Tropea, Daniela; Gill, Michael; Corvin, Aiden; Donohoe, Gary

2012-05-01

The nitric oxide synthasase-1 gene (NOS1) has been implicated in mental disorders including schizophrenia and variation in cognition. The NOS1 variant rs6490121 identified in a genome wide association study of schizophrenia has recently been associated with variation in general intelligence and working memory in both patients and healthy participants. Whether this variant is also associated with variation in early sensory processing remains unclear. We investigated differences in the P1 visual evoked potential in a high density EEG study of 54 healthy participants. Given both NOS1's association with cognition and recent evidence that cognitive performance and P1 response are correlated, we investigated whether NOS1's effect on P1 response was independent of its effects on cognition using CANTAB's spatial working memory (SWM) task. We found that carriers of the previously identified risk "G" allele showed significantly lower P1 responses than non-carriers. We also found that while P1 response and SWM performance were correlated, NOS1 continued to explain a significant proportion of variation in P1 response even when its effects on cognition were accounted for. The schizophrenia implicated NOS1 variants rs6490121 influences visual sensory processing as measured by the P1 response, either as part of the gene's pleiotropic effects on multiple aspects of brain function, or because of a primary influence on sensory processing that mediates the effects already seen in higher cognitive processes. Copyright © 2011 Wiley-Liss, Inc.

Stimulator with arbitrary waveform for auditory evoked potentials

International Nuclear Information System (INIS)

Martins, H R; Romao, M; Placido, D; Provenzano, F; Tierra-Criollo, C J

2007-01-01

The technological improvement helps many medical areas. The audiometric exams involving the auditory evoked potentials can make better diagnoses of auditory disorders. This paper proposes the development of a stimulator based on Digital Signal Processor. This stimulator is the first step of an auditory evoked potential system based on the ADSP-BF533 EZ KIT LITE (Analog Devices Company - USA). The stimulator can generate arbitrary waveform like Sine Waves, Modulated Amplitude, Pulses, Bursts and Pips. The waveforms are generated through a graphical interface programmed in C++ in which the user can define the parameters of the waveform. Furthermore, the user can set the exam parameters as number of stimuli, time with stimulation (Time ON) and time without stimulus (Time OFF). In future works will be implemented another parts of the system that includes the acquirement of electroencephalogram and signal processing to estimate and analyze the evoked potential

Stimulator with arbitrary waveform for auditory evoked potentials

Energy Technology Data Exchange (ETDEWEB)

Martins, H R; Romao, M; Placido, D; Provenzano, F; Tierra-Criollo, C J [Universidade Federal de Minas Gerais (UFMG), Departamento de Engenharia Eletrica (DEE), Nucleo de Estudos e Pesquisa em Engenharia Biomedica NEPEB, Av. Ant. Carlos, 6627, sala 2206, Pampulha, Belo Horizonte, MG, 31.270-901 (Brazil)

2007-11-15

The technological improvement helps many medical areas. The audiometric exams involving the auditory evoked potentials can make better diagnoses of auditory disorders. This paper proposes the development of a stimulator based on Digital Signal Processor. This stimulator is the first step of an auditory evoked potential system based on the ADSP-BF533 EZ KIT LITE (Analog Devices Company - USA). The stimulator can generate arbitrary waveform like Sine Waves, Modulated Amplitude, Pulses, Bursts and Pips. The waveforms are generated through a graphical interface programmed in C++ in which the user can define the parameters of the waveform. Furthermore, the user can set the exam parameters as number of stimuli, time with stimulation (Time ON) and time without stimulus (Time OFF). In future works will be implemented another parts of the system that includes the acquirement of electroencephalogram and signal processing to estimate and analyze the evoked potential.

Evoking prescribed spike times in stochastic neurons

Science.gov (United States)

Doose, Jens; Lindner, Benjamin

2017-09-01

Single cell stimulation in vivo is a powerful tool to investigate the properties of single neurons and their functionality in neural networks. We present a method to determine a cell-specific stimulus that reliably evokes a prescribed spike train with high temporal precision of action potentials. We test the performance of this stimulus in simulations for two different stochastic neuron models. For a broad range of parameters and a neuron firing with intermediate firing rates (20-40 Hz) the reliability in evoking the prescribed spike train is close to its theoretical maximum that is mainly determined by the level of intrinsic noise.

Cervical and ocular vestibular evoked potentials in Machado-Joseph disease: Functional involvement of otolith pathways.

Science.gov (United States)

Ribeiro, Rodrigo Souza; Pereira, Melissa Marques; Pedroso, José Luiz; Braga-Neto, Pedro; Barsottini, Orlando Graziani Povoas; Manzano, Gilberto Mastrocola

2015-11-15

Machado-Joseph disease is defined as an autosomal dominant ataxic disorder caused by degeneration of the cerebellum and its connections and is associated with a broad range of clinical symptoms. The involvement of the vestibular system is responsible for several symptoms and signs observed in the individuals affected by the disease. We measured cervical and ocular vestibular evoked myogenic potentials in a sample of Machado-Joseph disease patients in order to assess functional pathways involved. Bilateral measures of cervical and ocular vestibular evoked myogenic potentials (cVEMP and oVEMP) were obtained from 14 symptomatic patients with genetically proven Machado-Joseph disease and compared with those from a control group of 20 healthy subjects. Thirteen (93%) patients showed at least one abnormal test result; oVEMP and cVEMP responses were absent in 17/28 (61%) and 11/28 (39%) measures, respectively; and prolonged latency of cVEMP was found in 3/28 (11%) measures. Of the 13 patients with abnormal responses, 9/13 (69%) patients showed discordant abnormal responses: four with absent oVEMP and present cVEMP, two with absent cVEMP and present oVEMP, and three showed unilateral prolonged cVEMP latencies. Both otolith-related vestibulocollic and vestibulo-ocular pathways are severely affected in Machado-Joseph disease patients evaluated by VEMPs. Copyright © 2015 Elsevier B.V. All rights reserved.

Evoked Emotions Predict Food Choice

NARCIS (Netherlands)

Dalenberg, Jelle R.; Gutjar, Swetlana; ter Horst, Gert J.; de Graaf, Kees; Renken, Remco J.; Jager, Gerry

2014-01-01

In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments.

The effects of curiosity-evoking events on activity enjoyment.

Science.gov (United States)

Isikman, Elif; MacInnis, Deborah J; Ülkümen, Gülden; Cavanaugh, Lisa A

2016-09-01

Whereas prior literature has studied the positive effects of curiosity-evoking events that are integral to focal activities, we explore whether and how a curiosity-evoking event that is incidental to a focal activity induces negative outcomes for enjoyment. Four experiments and 1 field study demonstrate that curiosity about an event that is incidental to an activity in which individuals are engaged, significantly affects enjoyment of a concurrent activity. The reason why is that curiosity diverts attention away from the concurrent activity and focuses attention on the curiosity-evoking event. Thus, curiosity regarding an incidental event decreases enjoyment of a positive focal activity but increases enjoyment of a negative focal activity. PsycINFO Database Record (c) 2016 APA, all rights reserved

Vestibular Evoked Myogenic Potential Produced by Bone-Conducted Stimuli: A Study on its Basics and Clinical Applications in Patients With Conductive and Sensorineural Hearing Loss and a Group With Vestibular Schawannoma

Directory of Open Access Journals (Sweden)

Parvane Mahdi

2013-06-01

Full Text Available Introduction: Vestibular evoked myogenic potential (VEMP has recently been broadly studied in vestibular disorders. As it is evoked by loud sound stimulation, even mild conductive hearing loss may affect VEMP results. Bone-conducted (BC stimulus is an alternative stimulation for evoking this response. This study aims to assess the characteristics of BC-VEMP in different groups of patients.   Materials and Methods: We performed a cross sectional analysis on 20 healthy volunteers with normal pure-tone audiometry as a control group; and on a group of patients consisted of 20 participants with conductive hearing loss, five with bilateral sensorineural hearing loss and four with vestibular schawannoma. AC and BC-VEMP were performed in all participants.   Results: In control group the VEMP responses to both kinds of stimuli had an acceptable morphology and consisted of p13 and n23 waves. Latency value of these main components in each type of stimulus was not significantly different (P>0.05. However, the mean amplitude was larger in BC modality than AC stimulation (P=0.025. In the group with conductive hearing loss, the VEMP response was absent in fifteen (46.87% of the 32 ears using the AC method, whereas all (100% displayed positive elicitability of VEMP by BC method. Normal VEMP responses in both stimuli were evoked in all patients with sensorineural hearing loss. In patients with unilateral vestibular schwannomas (VS, 2 (50.00% had neither AC-VEMP nor BC-VEMP. Conclusion:  Auditory stimuli delivered by bone conduction can evoke VEMP response. These responses are of vestibular origin and can be used in vestibular evaluation of patients with conductive hearing loss.

Reactivity of the isolated perfused rat tail vascular bed

Directory of Open Access Journals (Sweden)

A.S. França

1997-07-01

Full Text Available Isolated segments of the perfused rat tail artery display a high basal tone when compared to other isolated arteries such as the mesenteric and are suitable for the assay of vasopressor agents. However, the perfusion of this artery in the entire tail has not yet been used for functional studies. The main purpose of the present study was to identify some aspects of the vascular reactivity of the rat tail vascular bed and validate this method to measure vascular reactivity. The tail severed from the body was perfused with Krebs solution containing different Ca2+ concentrations at different flow rates. Rats were anesthetized with sodium pentobarbital (65 mg/kg and heparinized (500 U. The tail artery was dissected near the tail insertion, cannulated and perfused with Krebs solution plus 30 µM EDTA at 36oC and 2.5 ml/min and the procedures were started after equilibration of the perfusion pressure. In the first group a dose-response curve to phenylephrine (PE (0.5, 1, 2 and 5 µg, bolus injection was obtained at different flow rates (1.5, 2.5 and 3.5 ml/min. The mean perfusion pressure increased with flow as well as PE vasopressor responses. In a second group the flow was changed (1.5, 2, 2.5, 3 and 3.5 ml/min at different Ca2+ concentrations (0.62, 1.25, 2.5 and 3.75 mM in the Krebs solution. Increasing Ca2+ concentrations did not alter the flow-pressure relationship. In the third group a similar protocol was performed but the rat tail vascular bed was perfused with Krebs solution containing PE (0.1 µg/ml. There was an enhancement of the effect of PE with increasing external Ca2+ and flow. PE vasopressor responses increased after endothelial damage with air and CHAPS, suggesting an endothelial modulation of the tone of the rat tail vascular bed. These experiments validate the perfusion of the rat tail vascular bed as a method to investigate vascular reactivity

The Role of Auditory Evoked Potentials in the Context of Cochlear Implant Provision.

Science.gov (United States)

Hoth, Sebastian; Dziemba, Oliver Christian

2017-12-01

: Auditory evoked potentials (AEP) are highly demanded during the whole process of equipping patients with cochlear implants (CI). They play an essential role in preoperative diagnostics, intraoperative testing, and postoperative monitoring of auditory performance and success. The versatility of AEP's is essentially enhanced by their property to be evokable by acoustic as well as electric stimuli. Thus, the electric responses of the auditory system following acoustic stimulation and recorded by the conventional surface technique as well as by transtympanic derivation from the promontory (Electrocochleography [ECochG]) are used for the quantitative determination of hearing loss and, additionally, electrically evoked compound actions potentials (ECAP) can be recorded with the intracochlear electrodes of the implant just adjacent to the stimulation electrode to check the functional integrity of the device and its coupling to the auditory system. The profile of ECAP thresholds is used as basis for speech processor fitting, the spread of excitation (SOE) allows the identification of electrode mislocations such as array foldover, and recovery functions may serve to optimize stimulus pulse rate. These techniques as well as those relying on scalp surface activity originating in the brainstem or the auditory cortex accompany the CI recipient during its whole life span and they offer valuable insights into functioning and possible adverse effects of the CI for clinical and scientific purposes.

Neuromagnetic detection of the laryngeal area: Sensory-evoked fields to air-puff stimulation.

Science.gov (United States)

Miyaji, Hideaki; Hironaga, Naruhito; Umezaki, Toshiro; Hagiwara, Koichi; Shigeto, Hiroshi; Sawatsubashi, Motohiro; Tobimatsu, Shozo; Komune, Shizuo

2014-03-01

The sensory projections from the oral cavity, pharynx, and larynx are crucial in assuring safe deglutition, coughing, breathing, and voice production/speaking. Although several studies using neuroimaging techniques have demonstrated cortical activation related to pharyngeal and laryngeal functions, little is known regarding sensory projections from the laryngeal area to the somatosensory cortex. The purpose of this study was to establish the cortical activity evoked by somatic air-puff stimulation at the laryngeal mucosa using magnetoencephalography. Twelve healthy volunteers were trained to inhibit swallowing in response to air stimuli delivered to the larynx. Minimum norm estimates was performed on the laryngeal somatosensory evoked fields (LSEFs) to best differentiate the target activations from non-task-related activations. Evoked magnetic fields were recorded with acceptable reproducibility in the left hemisphere, with a peak latency of approximately 100ms in 10 subjects. Peak activation was estimated at the caudolateral region of the primary somatosensory area (S1). These results establish the ability to detect LSEFs with an acceptable reproducibility within a single subject and among subjects. These results also suggest the existence of laryngeal somatic afferent input to the caudolateral region of S1 in human. Our findings indicate that further investigation in this area is needed, and should focus on laryngeal lateralization, swallowing, and speech processing. Copyright © 2013 Elsevier Inc. All rights reserved.

Additive Manufacturing of Vascular Grafts and Vascularized Tissue Constructs.

Science.gov (United States)

Elomaa, Laura; Yang, Yunzhi Peter

2017-10-01

There is a great need for engineered vascular grafts among patients with cardiovascular diseases who are in need of bypass therapy and lack autologous healthy blood vessels. In addition, because of the severe worldwide shortage of organ donors, there is an increasing need for engineered vascularized tissue constructs as an alternative to organ transplants. Additive manufacturing (AM) offers great advantages and flexibility of fabrication of cell-laden, multimaterial, and anatomically shaped vascular grafts and vascularized tissue constructs. Various inkjet-, extrusion-, and photocrosslinking-based AM techniques have been applied to the fabrication of both self-standing vascular grafts and porous, vascularized tissue constructs. This review discusses the state-of-the-art research on the use of AM for vascular applications and the key criteria for biomaterials in the AM of both acellular and cellular constructs. We envision that new smart printing materials that can adapt to their environment and encourage rapid endothelialization and remodeling will be the key factor in the future for the successful AM of personalized and dynamic vascular tissue applications.

Contraction-evoked vasodilation and functional hyperaemia are compromised in branching skeletal muscle arterioles of young pre-diabetic mice.

Science.gov (United States)

Novielli, N M; Jackson, D N

2014-06-01

To investigate the effects of pre-diabetes on microvascular network function in contracting skeletal muscle. We hypothesized that pre-diabetes compromises contraction-evoked vasodilation of branching second-order (2A), third-order (3A) and fourth-order (4A) arterioles, where distal arterioles would be affected the greatest. Intravital video microscopy was used to measure arteriolar diameter (in 2A, 3A and 4A) and blood flow (in 2A and 3A) changes to electrical field stimulation of the gluteus maximus muscle in pre-diabetic (The Pound Mouse, PD) and control (c57bl6, CTRL) mice. Baseline diameter and blood flow were similar between groups (2A: ~20 μm, 3A: ~14 μm and 4A: ~8 μm; 2A: ~1 nL s(-1) and 3A: ~0.5 nL s(-1) ). Single tetanic contraction (100 Hz; 200, 400, 800 ms duration) evoked rapid-onset vasodilation (ROV) and blood flow responses that were blunted by ~50% and up to 81%, respectively, in PD vs. CTRL (P contraction (2 and 8 Hz, 30 s) evoked vasodilatory and blood flow responses that were also attenuated by ~50% and up to 71%, respectively, in PD vs. CTRL (P contraction was also up to 2.5-fold greater at 4A vs. 2A in CTRL; however spatial differences in vasodilation across arteriolar branch orders was disrupted in PD. Arteriolar dysregulation in pre-diabetes causes deficits in contraction-evoked dilation and blood flow, where greatest deficits occur at distal arterioles. © 2014 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Photoacoustic discrimination of vascular and pigmented lesions using classical and Bayesian methods

Science.gov (United States)

Swearingen, Jennifer A.; Holan, Scott H.; Feldman, Mary M.; Viator, John A.

2010-01-01

Discrimination of pigmented and vascular lesions in skin can be difficult due to factors such as size, subungual location, and the nature of lesions containing both melanin and vascularity. Misdiagnosis may lead to precancerous or cancerous lesions not receiving proper medical care. To aid in the rapid and accurate diagnosis of such pathologies, we develop a photoacoustic system to determine the nature of skin lesions in vivo. By irradiating skin with two laser wavelengths, 422 and 530 nm, we induce photoacoustic responses, and the relative response at these two wavelengths indicates whether the lesion is pigmented or vascular. This response is due to the distinct absorption spectrum of melanin and hemoglobin. In particular, pigmented lesions have ratios of photoacoustic amplitudes of approximately 1.4 to 1 at the two wavelengths, while vascular lesions have ratios of about 4.0 to 1. Furthermore, we consider two statistical methods for conducting classification of lesions: standard multivariate analysis classification techniques and a Bayesian-model-based approach. We study 15 human subjects with eight vascular and seven pigmented lesions. Using the classical method, we achieve a perfect classification rate, while the Bayesian approach has an error rate of 20%.

Attenuation of insulin-evoked responses in brain networks controlling appetite and reward in insulin resistance: the cerebral basis for impaired control of food intake in metabolic syndrome?

Science.gov (United States)

Anthony, Karen; Reed, Laurence J; Dunn, Joel T; Bingham, Emma; Hopkins, David; Marsden, Paul K; Amiel, Stephanie A

2006-11-01

The rising prevalence of obesity and type 2 diabetes is a global challenge. A possible mechanism linking insulin resistance and weight gain would be attenuation of insulin-evoked responses in brain areas relevant to eating in systemic insulin resistance. We measured brain glucose metabolism, using [(18)F]fluorodeoxyglucose positron emission tomography, in seven insulin-sensitive (homeostasis model assessment of insulin resistance [HOMA-IR] = 1.3) and seven insulin-resistant (HOMA-IR = 6.3) men, during suppression of endogenous insulin by somatostatin, with and without an insulin infusion that elevated insulin to 24.6 +/- 5.2 and 23.2 +/- 5.8 mU/l (P = 0.76), concentrations similar to fasting levels of the resistant subjects and approximately threefold above those of the insulin-sensitive subjects. Insulin-evoked change in global cerebral metabolic rate for glucose was reduced in insulin resistance (+7 vs. +17.4%, P = 0.033). Insulin was associated with increased metabolism in ventral striatum and prefrontal cortex and with decreased metabolism in right amygdala/hippocampus and cerebellar vermis (P reward. Diminishing the link be-tween control of food intake and energy balance may contribute to development of obesity in insulin resistance.

Dynamic causal modeling of touch-evoked potentials in the rubber hand illusion.

Science.gov (United States)

Zeller, Daniel; Friston, Karl J; Classen, Joseph

2016-09-01

The neural substrate of bodily ownership can be disclosed by the rubber hand illusion (RHI); namely, the illusory self-attribution of an artificial hand that is induced by synchronous tactile stimulation of the subject's hand that is hidden from view. Previous studies have pointed to the premotor cortex (PMC) as a pivotal area in such illusions. To investigate the effective connectivity between - and within - sensory and premotor areas involved in bodily perceptions, we used dynamic causal modeling of touch-evoked responses in 13 healthy subjects. Each subject's right hand was stroked while viewing their own hand ("REAL"), or an artificial hand presented in an anatomically plausible ("CONGRUENT") or implausible ("INCONGRUENT") position. Bayesian model comparison revealed strong evidence for a differential involvement of the PMC in the generation of touch-evoked responses under the three conditions, confirming a crucial role of PMC in bodily self-attribution. In brief, the extrinsic (forward) connection from left occipital cortex to left PMC was stronger for CONGRUENT and INCONGRUENT as compared to REAL, reflecting the augmentation of bottom-up visual input when multisensory integration is challenged. Crucially, intrinsic connectivity in the primary somatosensory cortex (S1) was attenuated in the CONGRUENT condition, during the illusory percept. These findings support predictive coding models of the functional architecture of multisensory integration (and attenuation) in bodily perceptual experience. Copyright © 2016 Elsevier Inc. All rights reserved.

Blocking proteinase-activated receptor 2 alleviated neuropathic pain evoked by spinal cord injury.

Science.gov (United States)

Wei, H; Wei, Y; Tian, F; Niu, T; Yi, G

2016-01-01

Spinal cord injury (SCI) is an extremely serious type of physical trauma observed in clinics. Especially, neuropathic pain resulting from SCI has a lasting and significant impact on most aspects of daily life. Thus, a better understanding of the molecular pathways responsible for the cause of neuropathic pain observed in SCI is important to develop effectively therapeutic agents and treatment strategies. Proteinase-activated receptors (PARs) are a family member of G-protein-coupled receptors and are activated by a proteolytic mechanism. One of its subtypes PAR2 has been reported to be engaged in mechanical and thermal hyperalgesia. Thus, in this study we specifically examined the underlying mechanisms responsible for SCI evoked-neuropathic pain in a rat model. Overall, we demonstrated that SCI increases PAR2 and its downstream pathways TRPV1 and TRPA1 expression in the superficial dorsal horn of the spinal cord. Also, we showed that blocking spinal PAR2 by intrathecal injection of FSLLRY-NH2 significantly inhibits neuropathic pain responses induced by mechanical and thermal stimulation whereas FSLLRY-NH2 decreases the protein expression of TRPV1 and TRPA1 as well as the levels of substance P and calcitonin gene-related peptide. Results of this study have important implications, i.e. targeting one or more of these signaling molecules involved in activation of PAR2 and TRPV1/TRPA1 evoked by SCI may present new opportunities for treatment and management of neuropathic pain often observed in patients with SCI.

Angiotensin II and CRF Receptors in the Central Nucleus of the Amygdala Mediate Hemodynamic Response Variability to Cocaine in Conscious Rats

OpenAIRE

Watanabe, Mari A.; Kucenas, Sarah; Bowman, Tamara A.; Ruhlman, Melissa; Knuepfer, Mark M.

2009-01-01

Stress or cocaine evokes either a large increase in systemic vascular resistance (SVR) or a smaller increase in SVR accompanied by an increase in cardiac output (designated vascular and mixed responders, respectively) in Sprague-Dawley rats. We hypothesized that the central nucleus of the amygdala (CeA) mediates this variability. Conscious, freely-moving rats, instrumented for measurement of arterial pressure and cardiac output and for drug delivery into the CeA, were given cocaine (5 mg/kg, ...

MicroRNA-125b Affects Vascular Smooth Muscle Cell Function by Targeting Serum Response Factor

Directory of Open Access Journals (Sweden)

Zhibo Chen

2018-04-01

Full Text Available Background/Aims: Increasing evidence links microRNAs to the pathogenesis of peripheral vascular disease. We recently found microRNA-125b (miR-125b to be one of the most significantly down‑regulated microRNAs in human arteries with arteriosclerosis obliterans (ASO of the lower extremities. However, its function in the process of ASO remains unclear. This study aimed to investigate the expression, regulatory mechanisms, and functions of miR-125b in the process of ASO. Methods: Using the tissue explants adherent method, vascular smooth muscle cells (VSMCs were prepared for this study. A rat carotid artery balloon injury model was constructed to simulate the development of vascular neointima, and a lentiviral transduction system was used to overexpress serum response factor (SRF or miR-125b. Quantitative real‑time PCR (qRT‑PCR was used to detect the expression levels of miR‑125b and SRF mRNA. Western blotting was performed to determine the expression levels of SRF and Ki67. In situ hybridization analysis was used to analyze the location and expression levels of miR-125b. CCK-8 and EdU assays were used to assess cell proliferation, and transwell and wound closure assays were performed to measure cell migration. Flow cytometry was used to evaluate cell apoptosis, and a dual-luciferase reporter assay was conducted to examine the effects of miR‑125b on SRF. Immunohistochemistry and immunofluorescence analyses were performed to analyze the location and expression levels of SRF and Ki67. Results: miR-125b expression was decreased in ASO arteries and platelet-derived growth factor (PDGF-BB-stimulated VSMCs. miR-125b suppressed VSMC proliferation and migration but promoted VSMC apoptosis. SRF was determined to be a direct target of miR-125b. Exogenous miR-125b expression modulated SRF expression and inhibited vascular neointimal formation in balloon-injured rat carotid arteries. Conclusions: These findings demonstrate a specific role of the mi

[The modified method registration of kinesthetic evoked potentials and its application for research of proprioceptive sensitivity disorders at spondylogenic cervical myelopathy].

Science.gov (United States)

Gordeev, S A; Voronin, S G

2016-01-01

To analyze the efficacy of modified (passive radiocarpal articulation flexion/extension) and «standard» (passive radiocarpal articulation flexion) methods of kinesthetic evoked potentials for proprioceptive sensitivity assessment in healthy subjects and patients with spondylotic cervical myelopathy. The study included 14 healthy subjects (4 women and 10 men, mean age 54.1±10.5 years) and 8 patients (2 women and 6 men, mean age 55.8±10.9 years) with spondylotic cervical myelopathy. Muscle-joint sensation was examined during the clinical study. A modified method of kinesthetic evoked potentials was developed. This method differed from the "standard" one by the organization of a cycle including several passive movements,where each new movement differed from the preceding one by the direction. The modified method of kinesthetic evoked potentials ensures more reliable kinesthetic sensitivity assessment due to movement variability. Asignificant increaseof the latent periods of the early components of the response was found in patients compared to healthy subjects. The modified method of kinesthetic evoked potentials can be used for objective diagnosis of proprioceptive sensitivity disorders in patients with spondylotic cervical myelopathy.

Effectiveness of evaluating tumor vascularization using 3D power Doppler ultrasound with high-definition flow technology in the prediction of the response to neoadjuvant chemotherapy for T2 breast cancer: a preliminary report.

Science.gov (United States)

Shia, Wei-Chung; Chen, Dar-Ren; Huang, Yu-Len; Wu, Hwa-Koon; Kuo, Shou-Jen

2015-10-07

The aim of this study was to evaluate the effectiveness of advanced ultrasound (US) imaging of vascular flow and morphological features in the prediction of a pathologic complete response (pCR) and a partial response (PR) to neoadjuvant chemotherapy for T2 breast cancer.Twenty-nine consecutive patients with T2 breast cancer treated with six courses of anthracycline-based neoadjuvant chemotherapy were enrolled. Three-dimensional (3D) power Doppler US with high-definition flow (HDF) technology was used to investigate the blood flow in and morphological features of the tumors. Six vascularity quantization features, three morphological features, and two vascular direction features were selected and extracted from the US images. A support vector machine was used to evaluate the changes in vascularity after neoadjuvant chemotherapy, and pCR and PR were predicted on the basis of these changes.The most accurate prediction of pCR was achieved after the first chemotherapy cycle, with an accuracy of 93.1% and a specificity of 85.5%, while that of a PR was achieved after the second cycle, with an accuracy of 79.31% and a specificity of 72.22%.Vascularity data can be useful to predict the effects of neoadjuvant chemotherapy. Determination of changes in vascularity after neoadjuvant chemotherapy using 3D power Doppler US with HDF can generate accurate predictions of the patient response, facilitating early decision-making.

Effectiveness of evaluating tumor vascularization using 3D power Doppler ultrasound with high-definition flow technology in the prediction of the response to neoadjuvant chemotherapy for T2 breast cancer: a preliminary report

International Nuclear Information System (INIS)

Shia, Wei-Chung; Chen, Dar-Ren; Huang, Yu-Len; Wu, Hwa-Koon; Kuo, Shou-Jen

2015-01-01

The aim of this study was to evaluate the effectiveness of advanced ultrasound (US) imaging of vascular flow and morphological features in the prediction of a pathologic complete response (pCR) and a partial response (PR) to neoadjuvant chemotherapy for T2 breast cancer.Twenty-nine consecutive patients with T2 breast cancer treated with six courses of anthracycline-based neoadjuvant chemotherapy were enrolled. Three-dimensional (3D) power Doppler US with high-definition flow (HDF) technology was used to investigate the blood flow in and morphological features of the tumors. Six vascularity quantization features, three morphological features, and two vascular direction features were selected and extracted from the US images. A support vector machine was used to evaluate the changes in vascularity after neoadjuvant chemotherapy, and pCR and PR were predicted on the basis of these changes.The most accurate prediction of pCR was achieved after the first chemotherapy cycle, with an accuracy of 93.1% and a specificity of 85.5%, while that of a PR was achieved after the second cycle, with an accuracy of 79.31% and a specificity of 72.22%.Vascularity data can be useful to predict the effects of neoadjuvant chemotherapy. Determination of changes in vascularity after neoadjuvant chemotherapy using 3D power Doppler US with HDF can generate accurate predictions of the patient response, facilitating early decision-making. (paper)

Effectiveness of evaluating tumor vascularization using 3D power Doppler ultrasound with high-definition flow technology in the prediction of the response to neoadjuvant chemotherapy for T2 breast cancer: a preliminary report

Science.gov (United States)

Shia, Wei-Chung; Chen, Dar-Ren; Huang, Yu-Len; Wu, Hwa-Koon; Kuo, Shou-Jen

2015-10-01

The aim of this study was to evaluate the effectiveness of advanced ultrasound (US) imaging of vascular flow and morphological features in the prediction of a pathologic complete response (pCR) and a partial response (PR) to neoadjuvant chemotherapy for T2 breast cancer. Twenty-nine consecutive patients with T2 breast cancer treated with six courses of anthracycline-based neoadjuvant chemotherapy were enrolled. Three-dimensional (3D) power Doppler US with high-definition flow (HDF) technology was used to investigate the blood flow in and morphological features of the tumors. Six vascularity quantization features, three morphological features, and two vascular direction features were selected and extracted from the US images. A support vector machine was used to evaluate the changes in vascularity after neoadjuvant chemotherapy, and pCR and PR were predicted on the basis of these changes. The most accurate prediction of pCR was achieved after the first chemotherapy cycle, with an accuracy of 93.1% and a specificity of 85.5%, while that of a PR was achieved after the second cycle, with an accuracy of 79.31% and a specificity of 72.22%. Vascularity data can be useful to predict the effects of neoadjuvant chemotherapy. Determination of changes in vascularity after neoadjuvant chemotherapy using 3D power Doppler US with HDF can generate accurate predictions of the patient response, facilitating early decision-making.

Increased Evoked Potentials and Behavioral Indices in Response to Pain Among Individuals with Intellectual Disability.

Science.gov (United States)

Benromano, Tali; Pick, Chaim G; Granovsky, Yelena; Defrin, Ruth

2017-09-01

Previous studies on the sensitivity and reactivity to pain of individuals with intellectual disability (ID) are inconsistent. The inconsistency may result from the reliance on self-reports and facial expressions of pain that are subject to internal and external biases. The aim was therefore to evaluate the reactivity to pain of individuals with ID by recording pain-evoked potentials (EPs), here for the first time, and testing their association with behavioral pain indices. Forty-one healthy adults, 16 with mild-moderate ID and 25 controls. Subjects received series of phasic heat stimuli and rated their pain on self-report scales. Changes in facial expressions and in pain EPs were recorded and analyzed offline. Pain self-reports, facial expressions, and the N2P2 amplitudes of the EPs exhibited stimulus-response relationship with stimulation intensity in both groups. The facial expressions and N2P2 amplitudes of individuals with ID were increased and N2P2 latency prolonged compared with controls. N2P2 amplitudes correlated with self-reports only in controls. Individuals with ID are hypersensitive/reactive to pain, a finding bearing clinical implications. Although pain EPs may reflect a somewhat different aspect of pain than the behavioral indices do, there is evidence to support their use to record pain in noncommunicative individuals, pending further validation. © 2017 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Norepinephrine-evoked pain in fibromyalgia. A randomized pilot study [ISRCTN70707830

Directory of Open Access Journals (Sweden)

Casanova Jose-Miguel

2002-01-01

Full Text Available Abstract Background Fibromyalgia syndrome displays sympathetically maintained pain features such as frequent post-traumatic onset and stimuli-independent pain accompanied by allodynia and paresthesias. Heart rate variability studies showed that fibromyalgia patients have changes consistent with ongoing sympathetic hyperactivity. Norepinephrine-evoked pain test is used to assess sympathetically maintained pain syndromes. Our objective was to define if fibromyalgia patients have norepinephrine-evoked pain. Methods Prospective double blind controlled study. Participants: Twenty FM patients, and two age/sex matched control groups; 20 rheumatoid arthritis patients and 20 healthy controls. Ten micrograms of norepinephrine diluted in 0.1 ml of saline solution were injected in a forearm. The contrasting substance, 0.1 ml of saline solution alone, was injected in the opposite forearm. Maximum local pain elicited during the 5 minutes post-injection was graded on a visual analog scale (VAS. Norepinephrine-evoked pain was diagnosed when norepinephrine injection induced greater pain than placebo injection. Intensity of norepinephrine-evoked pain was calculated as the difference between norepinephrine minus placebo-induced VAS scores. Results Norepinephrine-evoked pain was seen in 80 % of FM patients (95% confidence intervals 56.3 – 94.3%, in 30 % of rheumatoid arthritis patients and in 30 % of healthy controls (95% confidence intervals 11.9 – 54.3 (p Conclusions Fibromyalgia patients have norepinephrine-evoked pain. This finding supports the hypothesis that fibromyalgia may be a sympathetically maintained pain syndrome.

Deferoxamine improves coronary vascular responses to sympathetic stimulation in patients with type 1 diabetes mellitus

Energy Technology Data Exchange (ETDEWEB)

Hattori, Naoya; Bengel, Frank M.; Nekolla, Stephan G.; Drzezga, Alexander E.; Schwaiger, Markus [Nuklearmedizinische Klinik und Poliklinik, Klinikum Rechts der Isar, Technischen Universitaet Muenchen (Germany); Schnell, Oliver; Rihl, Julian; Standl, Eberhard [Diabetes Research Center, Schwabing City Hospital, Munich (Germany)

2002-07-01

Effects of oxygen-derived free radicals are suggested to be a potential pathogenic factor for endothelial dysfunction. In this study we sought to evaluate the effect of hydroxyl radicals on the human coronary vascular bed in type I diabetes mellitus using positron emission tomography (PET). Thirteen patients with type 1 diabetes underwent PET using nitrogen-13 ammonia at rest and during sympathetic stimulation with the cold pressor test (CPT). The rest-stress study protocol was repeated twice (on different days) using pre-stress infusion of either saline as placebo or deferoxamine, an iron chelator which inhibits generation of hydroxyl radicals. At rest, global MBF was higher in diabetics than in normal controls (78.1{+-}17.5 vs 63.2{+-}14.9 mg 100 g{sup -1} min{sup -1}, P<0.05) and myocardial vascular resistance (MVR) showed a trend towards lower values (patients, 1.28{+-}0.35; controls, 1.55{+-}0.32, P=NS). CPT increased MBF in all controls while 7/13 diabetics responded normally. CPT decreased MVR in 10/13 controls but in only 4/13 diabetics. There was no significant difference in the duration of diabetes, HbA1c, daily insulin dose, body mass index, or lipid profiles between patients with and patients without abnormal MBF or MVR responses. Pre-stress infusion of deferoxamine normalized MBF response in all six patients, and MVR response in six of the nine patients. Another group consisting of seven patients underwent a rest-rest protocol after infusion of deferoxamine and saline to investigate the effect of deferoxamine on resting MBF. Deferoxamine did not change the resting MBF (deferoxamine, 81{+-}17 ml 100 g{sup -1} min{sup -1}; saline, 75{+-}19 ml 100 g{sup -1} min{sup -1}, P=NS) or MVR (deferoxamine, 1.0{+-}0.5 mmHg ml{sup -1} 100 g{sup -1} min{sup -1}; saline, 1.2{+-}0.6 mmHg ml{sup -1} 100 g{sup -1} min{sup -1}, P=NS). In conclusion, inhibition of hydroxyl radical formation using deferoxamine significantly improved the responses of coronary

Modified cytoplasmic Ca2+ sequestration contributes to spinal cord injury-induced augmentation of nerve-evoked contractions in the rat tail artery.

Directory of Open Access Journals (Sweden)

Hussain Al Dera

Full Text Available In rat tail artery (RTA, spinal cord injury (SCI increases nerve-evoked contractions and the contribution of L-type Ca2+ channels to these responses. In RTAs from unoperated rats, these channels play a minor role in contractions and Bay K8644 (L-type channel agonist mimics the effects of SCI. Here we investigated the mechanisms underlying the facilitatory actions of SCI and Bay K8644 on nerve-evoked contractions of RTAs and the hypothesis that Ca2+ entering via L-type Ca2+ channels is rapidly sequestered by the sarcoplasmic reticulum (SR limiting its role in contraction. In situ electrochemical detection of noradrenaline was used to assess if Bay K8644 increased noradrenaline release. Perforated patch recordings were used to assess if SCI changed the Ca2+ current recorded in RTA myocytes. Wire myography was used to assess if SCI modified the effects of Bay K8644 and of interrupting SR Ca2+ uptake on nerve-evoked contractions. Bay K8644 did not change noradrenaline-induced oxidation currents. Neither the size nor gating of Ca2+ currents differed between myocytes from sham-operated (control and SCI rats. Bay K8644 increased nerve-evoked contractions in RTAs from both control and SCI rats, but the magnitude of this effect was reduced by SCI. By contrast, depleting SR Ca2+ stores with ryanodine or cyclopiazonic acid selectively increased nerve-evoked contractions in control RTAs. Cyclopiazonic acid also selectively increased the blockade of these responses by nifedipine (L-type channel blocker in control RTAs, whereas ryanodine increased the blockade produced by nifedipine in both groups of RTAs. These findings suggest that Ca2+ entering via L-type channels is normally rapidly sequestered limiting its access to the contractile mechanism. Furthermore, the findings suggest SCI reduces the role of this mechanism.

Neuronal responses to tactile stimuli and tactile sensations evoked by microstimulation in the human thalamic principal somatic sensory nucleus (ventral caudal).

Science.gov (United States)

Schmid, Anne-Christine; Chien, Jui-Hong; Greenspan, Joel D; Garonzik, Ira; Weiss, Nirit; Ohara, Shinji; Lenz, Frederick Arthur

2016-06-01

The normal organization and plasticity of the cutaneous core of the thalamic principal somatosensory nucleus (ventral caudal, Vc) have been studied by single-neuron recordings and microstimulation in patients undergoing awake stereotactic operations for essential tremor (ET) without apparent somatic sensory abnormality and in patients with dystonia or chronic pain secondary to major nervous system injury. In patients with ET, most Vc neurons responded to one of the four stimuli, each of which optimally activates one mechanoreceptor type. Sensations evoked by microstimulation were similar to those evoked by the optimal stimulus only among rapidly adapting neurons. In patients with ET, Vc was highly segmented somatotopically, and vibration, movement, pressure, and sharp sensations were usually evoked by microstimulation at separate sites in Vc. In patients with conditions including spinal cord transection, amputation, or dystonia, RFs were mismatched with projected fields more commonly than in patients with ET. The representation of the border of the anesthetic area (e.g., stump) or of the dystonic limb was much larger than that of the same part of the body in patients with ET. This review describes the organization and reorganization of human Vc neuronal activity in nervous system injury and dystonia and then proposes basic mechanisms. Copyright © 2016 the American Physiological Society.

Sirtuins, Cell Senescence, and Vascular Aging.

Science.gov (United States)

Kida, Yujiro; Goligorsky, Michael S

2016-05-01

The sirtuins (SIRTs) constitute a class of proteins with nicotinamide adenine dinucleotide-dependent deacetylase or adenosine diphosphate-ribosyltransferase activity. Seven SIRT family members have been identified in mammals, from SIRT1, the best studied for its role in vascular aging, to SIRT7. SIRT1 and SIRT2 are localized in the nucleus and cytoplasm. SIRT3, SIRT4, and SIRT5 are mitochondrial, and SIRT6 and SIRT7 are nuclear. Extensive studies have clearly revealed that SIRT proteins regulate diverse cell functions and responses to stressors. Vascular aging involves the aging process (senescence) of endothelial and vascular smooth muscle cells. Two types of cell senescence have been identified: (1) replicative senescence with telomere attrition; and (2) stress-induced premature senescence without telomere involvement. Both types of senescence induce vascular cell growth arrest and loss of vascular homeostasis, and contribute to the initiation and progression of cardiovascular diseases. Previous mechanistic studies have revealed in detail that SIRT1, SIRT3, and SIRT6 show protective functions against vascular aging, and definite vascular function of other SIRTs is under investigation. Thus, direct SIRT modulation and nicotinamide adenine dinucleotide stimulation of SIRT are promising candidates for cardiovascular disease therapy. A small number of pilot studies have been conducted to assess SIRT modulation in humans. These clinical studies have not yet provided convincing evidence that SIRT proteins alleviate morbidity and mortality in patients with cardiovascular diseases. The outcomes of multiple ongoing clinical trials are awaited to define the efficacy of SIRT modulators and SIRT activators in cardiovascular diseases, along with the potential adverse effects of chronic SIRT modulation. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Impact of arachidonic versus eicosapentaenoic acid on exotonin-induced lung vascular leakage: relation to 4-series versus 5-series leukotriene generation.

Science.gov (United States)

Grimminger, F; Wahn, H; Mayer, K; Kiss, L; Walmrath, D; Seeger, W

1997-02-01

Escherichia coli hemolysin (HlyA) is a proteinaceous pore-forming exotoxin that is implicated as a significant pathogenicity factor in extraintestinal E. coli infections including sepsis. In perfused rabbit lungs, subcytolytic concentrations of the toxin evoke thromboxane-mediated vasoconstriction and prostanoid-independent protracted vascular permeability increase (11). In the present study, the influence of submicromolar concentrations of free arachidonic acid (AA) and eicosapentaenoic acid (EPA) on the HlyA-induced leakage response was investigated. HlyA at concentration from 0.02 to 0.06 hemolytic units/ml provoked a dose-dependent, severalfold increase in the capillary filtration coefficient (Kfc), accompanied by the release of leukotriene(LT)B4, LTC4, and LTE4 into the recirculating buffer fluid. Simultaneous application of 100 nmol/L AA markedly augmented the HlyA-elicited leakage response, concomitant with an amplification of LTB4 release and a change in the kinetics of cysteinyl-LT generation. In contrast, 50 to 200 nmol/L EPA suppressed in a dose-dependent manner the HlyA-induced increase in Kfc values. This was accompanied by a blockage of 4-series LT generation and a dose-dependent appearance of LTB5, LTC5, and LTE5. In addition, EPA fully antagonized the AA-induced amplification of the HlyA-provoked Kfc increase, again accompanied by a shift from 4-series to 5-series LT generation. We conclude that the vascular leakage provoked by HlyA in rabbit lungs is differentially influenced by free AA versus free EPA, related to the generation of 4- versus 5-series leukotrienes. The composition of lipid emulsions used for parenteral nutrition may thus influence inflammatory capillary leakage.

The Nicotine-Evoked Locomotor Response: A Behavioral Paradigm for Toxicity Screening in Zebrafish (Danio rerio Embryos and Eleutheroembryos Exposed to Methylmercury.

Directory of Open Access Journals (Sweden)

Francisco X Mora-Zamorano

Full Text Available This study is an adaptation of the nicotine-evoked locomotor response (NLR assay, which was originally utilized for phenotype-based neurotoxicity screening in zebrafish embryos. Zebrafish embryos do not exhibit spontaneous swimming until roughly 4 days post-fertilization (dpf, however, a robust swimming response can be induced as early as 36 hours post-fertilization (hpf by means of acute nicotine exposure (30-240μM. Here, the NLR was tested as a tool for early detection of locomotor phenotypes in 36, 48 and 72 hpf mutant zebrafish embryos of the non-touch-responsive maco strain; this assay successfully discriminated mutant embryos from their non-mutant siblings. Then, methylmercury (MeHg was used as a proof-of-concept neurotoxicant to test the effectiveness of the NLR assay as a screening tool in toxicology. The locomotor effects of MeHg were evaluated in 6 dpf wild type eleutheroembryos exposed to waterborne MeHg (0, 0.01, 0.03 and 0.1μM. Afterwards, the NLR assay was tested in 48 hpf embryos subjected to the same MeHg exposure regimes. Embryos exposed to 0.01 and 0.03μM of MeHg exhibited significant increases in locomotion in both scenarios. These findings suggest that similar locomotor phenotypes observed in free swimming fish can be detected as early as 48 hpf, when locomotion is induced with nicotine.

Vascular endothelial growth factors: multitasking functionality in metabolism, health and disease.

Science.gov (United States)

Smith, Gina A; Fearnley, Gareth W; Harrison, Michael A; Tomlinson, Darren C; Wheatcroft, Stephen B; Ponnambalam, Sreenivasan

2015-07-01

Vascular endothelial growth factors (VEGFs) bind to VEGF receptor tyrosine kinases (VEGFRs). The VEGF and VEGFR gene products regulate diverse regulatory pathways in mammalian development, health and disease. The interaction between a particular VEGF and its cognate VEGFR activates multiple signal transduction pathways which regulate different cellular responses including metabolism, gene expression, proliferation, migration, and survival. The family of VEGF isoforms regulate vascular physiology and promote tissue homeostasis. VEGF dysfunction is implicated in major chronic disease states including atherosclerosis, diabetes, and cancer. More recent studies implicate a strong link between response to VEGF and regulation of vascular metabolism. Understanding how this family of multitasking cytokines regulates cell and animal function has implications for treating many different diseases.

Neurochemical responses to chromatic and achromatic stimuli in the human visual cortex.

Science.gov (United States)

Bednařík, Petr; Tkáč, Ivan; Giove, Federico; Eberly, Lynn E; Deelchand, Dinesh K; Barreto, Felipe R; Mangia, Silvia

2018-02-01

In the present study, we aimed at determining the metabolic responses of the human visual cortex during the presentation of chromatic and achromatic stimuli, known to preferentially activate two separate clusters of neuronal populations (called "blobs" and "interblobs") with distinct sensitivity to color or luminance features. Since blobs and interblobs have different cytochrome-oxidase (COX) content and micro-vascularization level (i.e., different capacities for glucose oxidation), different functional metabolic responses during chromatic vs. achromatic stimuli may be expected. The stimuli were optimized to evoke a similar load of neuronal activation as measured by the bold oxygenation level dependent (BOLD) contrast. Metabolic responses were assessed using functional 1 H MRS at 7 T in 12 subjects. During both chromatic and achromatic stimuli, we observed the typical increases in glutamate and lactate concentration, and decreases in aspartate and glucose concentration, that are indicative of increased glucose oxidation. However, within the detection sensitivity limits, we did not observe any difference between metabolic responses elicited by chromatic and achromatic stimuli. We conclude that the higher energy demands of activated blobs and interblobs are supported by similar increases in oxidative metabolism despite the different capacities of these neuronal populations.

Activation of vascular cholinergic and adrenergic receptors induced by gamma rays

International Nuclear Information System (INIS)

Alya, G.

1999-10-01

Activation of vascular cholinergic receptors and adrenoceptors plays an important role in vasomotoricity and peripheric vascular resistance. These factors are essential in maintaining a stable blood pressure. The aim of this study is to investigate the radiosensitivity differences between vascular cholinergic receptors and adrenoceptors, and consequently to determinate the effects of ionizing radiation (whole body irradiation) on contractile response regulation of vascular smooth muscle fibers VSMF isolated from rat portal vein. Our results show that Clonidine, (non-specific adrenergic agonist), and phenylephrine which is more specific α1-adrenoceptor agonist, increase the VSMF contractions. The maximum effect is obtained at 10 -5 - 3.10 -5 M. On irradiated rats (1-3-5 Gy), there is an important shift thus, the maximal response (E m ax) can be obtained in lower concentrations of clonidine and phenylephrine. Irradiation deceases the contractile responses of VSMF mediated by cholinergic stimulation, in a dose dependant manner. With E m ax 1 Gy>E m ax 3 Gy>E m ax 5 Gy. Irradiated muscular fibers became less sensitive to acetylcholine, thus 3.10 -8 M. A. ch induced more than 50% of contraction force increase in normal conditions. This concentration induce generally a negligible effect after irradiation. The results reveal the existence of radiosensitivity differences between vascular cholinergic and adrenergic receptors. (author)

Changes in Ultrasonographic Vascularity Upon Initiation of Adalimumab Combination Therapy in Rheumatoid Arthritis Patients With an Inadequate Response to Methotrexate.

Science.gov (United States)

Kaeley, Gurjit S; Nishio, Midori J; Goyal, Janak R; MacCarter, Daryl K; Wells, Alvin F; Chen, Su; Kupper, Hartmut; Kalabic, Jasmina

2016-11-01

To assess joint disease activity by ultrasound (US) in patients with rheumatoid arthritis (RA) initiating treatment with adalimumab (ADA) plus methotrexate (MTX). Data for this post hoc analysis originated from the MUSICA trial (ClinicalTrials.gov identifier: NCT01185288), which evaluated the efficacy of initiating ADA (40 mg every other week) plus 7.5 or 20 mg/week MTX in 309 patients with RA with an inadequate response to MTX. Synovial vascularization over 24 weeks was assessed bilaterally at metacarpophalangeal joint 2 (MCP2), MCP3, MCP5, metatarsophalangeal joint 5, and the wrists by power Doppler US (PDUS). A semiquantitative 4-grade scale was used. Disease activity was assessed using the Disease Activity Score in 28 joints using the C-reactive protein level (DAS28-CRP) and Simplified Disease Activity Index (SDAI). The correlation between continuous variables was assessed using Pearson's correlation coefficient. After 24 weeks of treatment with ADA plus MTX, rapid improvements in the mean synovial vascularity score were observed; the greatest improvements were in MCP2 (-0.5), MCP3 (-0.4), and the wrist (-0.4). At week 24, patients with the lowest DAS28-CRP ( 0.9). Synovial vascularity scores correlated poorly with DAS28, swollen joint count in 66 joints (SJC66), SJC28, tender joint count in 68 joints (TJC68), TJC28, Clinical Disease Activity Index (CDAI), SDAI, physician's global assessment, patient's global assessment of pain, and disease duration (ρ < 0.2). Thirty-two (70%) of 46 patients with a DAS28-CRP of <2.6, and 11 (58%) of 19 patients with an SDAI indicating remission had at least 1 joint with a synovial vascularity score of ≥1. PDUS detects changes in synovial vascularity in RA patients treated with ADA plus MTX, and residual synovial vascularity in patients in whom clinical disease control has been achieved. © 2016 The Authors. Arthritis & Rheumatology published by Wiley Periodicals, Inc. on behalf of the American College of Rheumatology.

Multifocal visual evoked responses to dichoptic stimulation using virtual reality goggles: Multifocal VER to dichoptic stimulation.

Science.gov (United States)

Arvind, Hemamalini; Klistorner, Alexander; Graham, Stuart L; Grigg, John R

2006-05-01

Multifocal visual evoked potentials (mfVEPs) have demonstrated good diagnostic capabilities in glaucoma and optic neuritis. This study aimed at evaluating the possibility of simultaneously recording mfVEP for both eyes with dichoptic stimulation using virtual reality goggles and also to determine the stimulus characteristics that yield maximum amplitude. ten healthy volunteers were recruited and temporally sparse pattern pulse stimuli were presented dichoptically using virtual reality goggles. Experiment 1 involved recording responses to dichoptically presented checkerboard stimuli and also confirming true topographic representation by switching off specific segments. Experiment 2 involved monocular stimulation and comparison of amplitude with Experiment 1. In Experiment 3, orthogonally oriented gratings were dichoptically presented. Experiment 4 involved dichoptic presentation of checkerboard stimuli at different levels of sparseness (5.0 times/s, 2.5 times/s, 1.66 times/s and 1.25 times/s), where stimulation of corresponding segments of two eyes were separated by 16.7, 66.7,116.7 & 166.7 ms respectively. Experiment 1 demonstrated good traces in all regions and confirmed topographic representation. However, there was suppression of amplitude of responses to dichoptic stimulation by 17.9+/-5.4% compared to monocular stimulation. Experiment 3 demonstrated similar suppression between orthogonal and checkerboard stimuli (p = 0.08). Experiment 4 demonstrated maximum amplitude and least suppression (4.8%) with stimulation at 1.25 times/s with 166.7 ms separation between eyes. It is possible to record mfVEP for both eyes during dichoptic stimulation using virtual reality goggles, which present binocular simultaneous patterns driven by independent sequences. Interocular suppression can be almost eliminated by using a temporally sparse stimulus of 1.25 times/s with a separation of 166.7 ms between stimulation of corresponding segments of the two eyes.

A Telehealth System for Remote Auditory Evoked Potential Monitoring

OpenAIRE

Millan, Jorge; Yunda, Leonardo

2013-01-01

A portable, Internet-based EEG/Auditory Evoked Potential (AEP) monitoring system was developed for remote electrophysiological studies during sleep. The system records EEG/AEP simultaneously at the subject?s home for increased comfort and flexibility. The system provides simultaneous recording and remote viewing of EEG, EMG and EOG waves and allows on-line averaging of auditory evoked potentials. The design allows the recording of all major AEP components (brainstem, middle and late latency E...

Retinal, optic nerve and chiasmal function following radiation therapy demonstrated by visual evoked response testing

International Nuclear Information System (INIS)

Soni, A.B.; Constine, L.S.; Smith, D.; Palisca, M.; Ojomo, K.; Muhs, A.

1997-01-01

Purpose: To evaluate the tolerance of the retina, optic nerve, and optic chiasm to radiation doses conventionally used to treat patients with primary brain or pituitary tumors and to explore the character of detectable radiation effects. Visual evoked response (VER) testing is a noninvasive and sensitive method for identifying radiation injury to the visual system due to alterations in small vessel or myelin integrity. Such evaluations may increase our understanding of the threshold for and the pathogenesis of radiation injury. Materials and Methods: Twenty-four patients irradiated for brain or pituitary tumors between 1972 and 1996 had VER testing. Patients were included in study if the retina, optic nerves or chiasm were in the radiation (RT) field. At the time of RT patients ranged in age from 1.5 to 55 years (median 33). Mean doses were as follows: right retina, 29 Gy (range 10 - 60 Gy); left retina, 29.5 Gy (range 10 - 60 Gy); right optic nerve, 42.9 Gy (range 10 - 60 Gy); left optic nerve, 42.6 Gy (range 10 - 60 Gy); and optic chiasm, 48.2 Gy (range 10 - 65 Gy). Daily fractionation ranged from 1.5 to 1.8 Gy. Pattern VER testing distinguishes compressive or ischemic effects of tumor on the visual system from radiation retinopathy or optic neuropathy on the basis of the conduction amplitude and delay pattern. Prechiasm, chiasm, and postchiasm injuries are distinguishable by analyzing VER changes. Four evoked responses were obtained for each eye, each representing the average of 100 stimulus reversals. Results: VER was normal in 11 patients and abnormal in 13 patients. Only 2 patients (8%) had VER evidence of radiation injury to the visual system, one of whom had visual compromise. The other 11 abnormal patients had characteristic VER changes attributable to tumor or surgical damage. There was no significant difference in the radiation doses given to any subgroup. The one patient with radiation retinopathy had received 55-60 Gy to the posterior globe. Ten years

Sex differences in the refractory period of the 100 ms auditory evoked magnetic field.

Science.gov (United States)

Rojas, D C; Teale, P; Sheeder, J; Reite, M

1999-11-08

The 100 ms latency auditory evoked magnetic response (M100) has been implicated in the earliest stage of acoustic memory encoding in the brain. Sex differences in this response have been found in its location within the brain and its functional properties. We recorded the M100 in 25 adults in response to changes in interstimulus interval of an auditory stimulus. Response amplitudes of the M100 were used to compute a measure of the M100 refractory period, which has been proposed to index the decay time constant of echoic memory. This time constant was significantly longer in both hemispheres of the female participants when compared to the male participants. Possible implications of this for behavioral sex differences in human memory performance are discussed.

Thought-evoking approaches in engineering problems

CERN Document Server

2014-01-01

In creating the value-added product in not distant future, it is necessary and inevitable to establish a holistic and though-evoking approach to the engineering problem, which should be at least associated with the inter-disciplinary knowledge and thought processes across the whole engineering spheres. It is furthermore desirable to integrate it with trans-disciplinary aspects ranging from manufacturing culture, through liberal-arts engineering, and industrial sociology.   The thought-evoking approach can be exemplified and typified by representative engineering problems: unveiling essential features in ‘Tangential Force Ratio and Interface Pressure’, prototype development for ‘Bio-mimetic Needle’ and application of ‘Water-jet Machining to Artificial Hip Joint’, product innovation in ‘Heat Sink for Computer’, application of ‘Graph Theory’ to similarity evaluation of production systems, leverage among reciprocity attributes in ‘Industrial and Engineering Designs for Machine Enclosure’,...

Sensorineural hearing loss among cerebellopontine-angle tumor patients examined with pure tone audiometry and brainstem-evoked response audiometry

Science.gov (United States)

Rinindra, A. M.; Zizlavsky, S.; Bashiruddin, J.; Aman, R. A.; Wulani, V.; Bardosono, S.

2017-08-01

Tumor in the cerebellopontine angle (CPA) accurs for approximately 5-10% of all intracranial tumors, where unilateral hearing loss and tinnitus are the most frequent symptoms. This study aimed to collect data on sensorineural hearing loss in CPA tumor patients in Dr. Cipto Mangunkusumo Hospital (CMH) using pure tone audiometry and brainstem-evoked response audiometry (BERA). It also aimed to obtaine data on CPA-tumor imaging through magnetic resonance imaging (MRI). This was a descriptive, analytic, and cross-sectional study. The subjects of this study were gathered using a total sampling method from secondary data between July 2012 and November 2016. From 104 patients, 30 matched the inclusion criteria. The CPA-tumor patients in the ENT CMH outpatient clinic were mostly female, middle-aged patients (41-60 years) whose clinical presentation was mostly tinnitus and severe, asymmetric sensorineural hearing loss in 10 subjects. From 30 subjects, 29 showed ipsilaterally impaired BERA results, and 17 subjects showed contralaterally impaired BERA results. There were 24 subjects who with large-sized tumors and 19 subjects who had intracanal tumors that had spread until they were extracanal in 19 subjects.

Vascular development of the grapevine (Vitis vinifera L.) inflorescence rachis in response to flower number, plant growth regulators and defoliation.

Science.gov (United States)

Gourieroux, Aude M; Holzapfel, Bruno P; McCully, Margaret E; Scollary, Geoffrey R; Rogiers, Suzy Y

2017-09-01

The grapevine inflorescence is a determinate panicle and as buds emerge, shoot, flower and rachis development occur simultaneously. The growth and architecture of the rachis is determined by genetic and environmental factors but here we examined the role of flower and leaf number as well as hormones on its elongation and vascular development. The consequences of rachis morphology and vascular area on berry size and composition were also assessed. One week prior to anthesis, Merlot and Cabernet Sauvignon field vines were exposed to manual flower removal, exogenous plant growth regulators or pre-bloom leaf removal. Manual removal of half the flowers along the vertical axis of the inflorescence resulted in a shorter rachis in both cultivars. Conversely, inflorescences treated with gibberellic acid (GA 3 ) and the synthetic cytokinin, 6-benzylaminopurine (BAP) resulted in a longer rachis while pre-bloom removal of all leaves on the inflorescence-bearing shoot did not alter rachis length relative to untreated inflorescences. Across the treatments, the cross-sectional areas of the conducting xylem and phloem in the rachis were positively correlated to rachis girth, flower number at anthesis, bunch berry number, bunch berry fresh mass and bunch sugar content at harvest. Conversely, average berry size and sugar content were not linked to rachis vascular area. These data indicate that the morphological and vascular development of the rachis was more responsive to flower number and plant growth regulators than to leaf removal.

Premature infants display increased noxious-evoked neuronal activity in the brain compared to healthy age-matched term-born infants.

Science.gov (United States)

Slater, Rebeccah; Fabrizi, Lorenzo; Worley, Alan; Meek, Judith; Boyd, Stewart; Fitzgerald, Maria

2010-08-15

This study demonstrates that infants who are born prematurely and who have experienced at least 40days of intensive or special care have increased brain neuronal responses to noxious stimuli compared to healthy newborns at the same postmenstrual age. We have measured evoked potentials generated by noxious clinically-essential heel lances in infants born at term (8 infants; born 37-40weeks) and in infants born prematurely (7 infants; born 24-32weeks) who had reached the same postmenstrual age (mean age at time of heel lance 39.2+/-1.2weeks). These noxious-evoked potentials are clearly distinguishable from shorter latency potentials evoked by non-noxious tactile sensory stimulation. While the shorter latency touch potentials are not dependent on the age of the infant at birth, the noxious-evoked potentials are significantly larger in prematurely-born infants. This enhancement is not associated with specific brain lesions but reflects a functional change in pain processing in the brain that is likely to underlie previously reported changes in pain sensitivity in older ex-preterm children. Our ability to quantify and measure experience-dependent changes in infant cortical pain processing will allow us to develop a more rational approach to pain management in neonatal intensive care. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Improvement of insulin sensitivity in response to exercise training in type 2 diabetes mellitus is associated with vascular endothelial growth factor A expression.

Science.gov (United States)

Wagner, Henrik; Fischer, Helene; Degerblad, Marie; Alvarsson, Michael; Gustafsson, Thomas

2016-09-01

Insulin sensitivity changes in response to exercise training demonstrate a large variation. Vascular endothelial growth factor A could promote increased insulin sensitivity through angiogenesis. We investigated associations between changes in expression of key genes and insulin sensitivity, aerobic capacity and glycaemic control following exercise training in diabetes mellitus type 2. Subjects with diabetes mellitus type 2 underwent 12 weeks of structured exercise. Euglycaemic clamp, exercise test and HbA1c were performed. Muscle biopsies were obtained for mRNA expression. A total of 16 subjects completed the study. Change in vascular endothelial growth factor A expression was positively associated with an increase in insulin sensitivity (p = 0.004) and with a decrease in HbA1c (p = 0.034). Vascular endothelial growth factor A receptor-1 expression showed similar associations. The variation in physical adaptation to exercise training in diabetes mellitus type 2 was associated with changes in expression of vascular endothelial growth factor A in muscle. This difference in induced gene expression could contribute to the variation in exercise training effects on insulin sensitivity. Measures of capillary blood flow need to be assessed in future studies. © The Author(s) 2016.

[Immunologic problems in vascular homografts].

Science.gov (United States)

D'Addato, M; Mirelli, M

2001-01-01

Fresh arterial homografts are immunogenic, inducing in recipient a strong immune response specifically directed against the antigens of the donor graft. The initial immune response seems to be cellular (lymphocytotoxic) and the late reaction humoral (antibody), even if they are strictly correlated. Immunosuppressive therapy reduce the immune reaction, but this response is dose-related. Implanted arterial homografts induce a donor-specific response similar to chronic reaction, which occurs in the recipients of vascularized solid-organ allografts. Therefore, in arterial transplantation, ABO compatibility and negative crossmatch should be respected. Effort should be made to curb the immune response by prospective cross-matching, immunosuppressive therapy and preoperative manipulation of homografts to reduce their antigenicity.

Skinfold thickness affects the isometric knee extension torque evoked by Neuromuscular Electrical Stimulation.

Science.gov (United States)

Medeiros, Flávia V A; Vieira, Amilton; Carregaro, Rodrigo L; Bottaro, Martim; Maffiuletti, Nicola A; Durigan, João L Q

2015-01-01

Subcutaneous adipose tissue may influence the transmission of electrical stimuli through to the skin, thus affecting both evoked torque and comfort perception associated with neuromuscular electrical stimulation (NMES). This could seriously affect the effectiveness of NMES for either rehabilitation or sports purposes. To investigate the effects of skinfold thickness (SFT) on maximal NMES current intensity, NMES-evoked torque, and NMES-induced discomfort. First, we compared NMES current intensity, NMES-induced discomfort, and NMES-evoked torque between two subgroups of subjects with thicker (n=10; 20.7 mm) vs. thinner (n=10; 29.4 mm) SFT. Second, we correlated SFT to NMES current intensity, NMES-induced discomfort, and NMES-evoked knee extension torque in 20 healthy women. The NMES-evoked torque was normalized to the maximal voluntary contraction (MVC) torque. The discomfort induced by NMES was assessed with a visual analog scale (VAS). NMES-evoked torque was 27.5% lower in subjects with thicker SFT (p=0.01) while maximal current intensity was 24.2% lower in subjects with thinner SFT (p=0.01). A positive correlation was found between current intensity and SFT (r=0.540, p=0.017). A negative correlation was found between NMES-evoked torque and SFT (r=-0.563, p=0.012). No significant correlation was observed between discomfort scores and SFT (rs=0.15, p=0.53). These results suggest that the amount of subcutaneous adipose tissue (as reflected by skinfold thickness) affected NMES current intensity and NMES-evoked torque, but had no effect on discomfort perception. Our findings may help physical therapists to better understand the impact of SFT on NMES and to design more rational stimulation strategies.

Effects of glutamate receptor agonists on the P13 auditory evoked potential and startle response in the rat

Directory of Open Access Journals (Sweden)

Christen eSimon

2011-01-01

Full Text Available The P13 potential is the rodent equivalent of the P50 potential, which is an evoked response recorded at the vertex (Vx 50 msec following an auditory stimulus in humans. Both the P13 and P50 potentials are only present during waking and rapid eye movement (REM sleep, and are considered to be measures of level of arousal. The source of the P13 and P50 potentials appears to be the pedunculopontine nucleus (PPN, a brainstem nucleus with indirect ascending projections to the cortex through the intralaminar thalamus (ILT, mediating arousal, and descending inhibitory projections to the caudal pontine reticular formation (CPRF, which mediates the auditory startle response (SR. We tested the hypothesis that intracranial microinjection (ICM of glutamate (GLU or GLU receptor agonists will increase the activity of PPN neurons, resulting in an increased P13 potential response, and decreased SR due to inhibitory projections from the PPN to the CPRF, in freely moving animals. Cannulae were inserted into the PPN to inject neuroactive agents, screws were inserted into the Vx in order to record the P13 potential, and electrodes inserted into the dorsal nuchal muscle to record electromyograms (EMGs and SR amplitude. Our results showed that ICM of GLU into the PPN dose-dependently increased the amplitude of the P13 potential and decreased the amplitude of the SR. Similarly, ICM of NMDA or KA into the PPN increased the amplitude of the P13 potential. These findings indicate that glutamatergic input to the PPN plays a role in arousal control in vivo, and changes in glutamatergic input, or excitability of PPN neurons, could be implicated in a number of neuropsychiatric disorders with the common symptoms of hyperarousal and REM sleep dysregulation.

The effects of ultraviolet-A radiation on visual evoked potentials in the young human eye

International Nuclear Information System (INIS)

Sanford, B.E.; Beacham, S.; Hanifin, J.P.; Hannon, P.; Streletz, L.; Sliney, D.; Brainard, G.C.

1996-01-01

A recent study from this laboratory using visual evoked potentials (VEPs) demonstrated that children's eyes are capable of detecting ultraviolet radiation. The aim of this study was to compare dose-response relationships in two age groups, 6-10 years (n=10) and 20-25 years (n=10). Under photopic viewing conditions (550 lux), exposures of monochromatic UV-A (339 nm) and visible radiation (502 nm) were correlated to VEPs. The results demonstrate that monochromatic UV-A can elicit age and dose dependent responses in the human visual system, suggesting that the eyes of children are more responsive to UV stimuli than the eyes of young adults. (au) 17 refs

Enhancing the radiation response of tumors but not early or late responding normal tissues using a vascular disrupting agent

DEFF Research Database (Denmark)

Horsman, Michael R

2017-01-01

INTRODUCTION: Vascular disrupting agents (VDAs) damage tumor vasculature and enhance tumor radiation response. In this pre-clinical study, we combined radiation with the leading VDA in clinical development, combretastatin A-4 phosphate (CA4P), and compared the effects seen in tumors and relevant...... normal tissues. MATERIAL AND METHODS: Radiation was applied locally to tissues in CDF1 mice to produce full radiation dose-response curves. CA4P (250 mg/kg) was intraperitoneally (i.p.) injected within 30 minutes after irradiating. Response of 200 mm3 foot implanted C3H mammary carcinomas was assessed......% increase in ventilation rate measured by plethysmography within 9 months). A Chi-squared test was used for statistical comparisons (significance level of p 4P. The radiation...

Transmitter modulation of spike-evoked calcium transients in arousal related neurons

DEFF Research Database (Denmark)

Kohlmeier, Kristi Anne; Leonard, Christopher S

2006-01-01

Nitric oxide synthase (NOS)-containing cholinergic neurons in the laterodorsal tegmentum (LDT) influence behavioral and motivational states through their projections to the thalamus, ventral tegmental area and a brainstem 'rapid eye movement (REM)-induction' site. Action potential-evoked intracel......Nitric oxide synthase (NOS)-containing cholinergic neurons in the laterodorsal tegmentum (LDT) influence behavioral and motivational states through their projections to the thalamus, ventral tegmental area and a brainstem 'rapid eye movement (REM)-induction' site. Action potential......-evoked intracellular calcium transients dampen excitability and stimulate NO production in these neurons. In this study, we investigated the action of several arousal-related neurotransmitters and the role of specific calcium channels in these LDT Ca(2+)-transients by simultaneous whole-cell recording and calcium...... of cholinergic LDT neurons and that inhibition of spike-evoked Ca(2+)-transients is a common action of neurotransmitters that also activate GIRK channels in these neurons. Because spike-evoked calcium influx dampens excitability, our findings suggest that these 'inhibitory' transmitters could boost firing rate...

Metformin inhibits inflammatory response via AMPK–PTEN pathway in vascular smooth muscle cells

International Nuclear Information System (INIS)

Kim, Sun Ae; Choi, Hyoung Chul

2012-01-01

Highlights: ► PTEN was induced by metformin and inhibited by compound C and AMPK siRNA. ► Metformin suppressed TNF-α-induced COX-2 and iNOS mRNA expression. ► Compound C and bpv (pic) increased iNOS and COX-2 protein expression. ► NF-κB activation was restored by inhibiting AMPK and PTEN. ► AMPK and PTEN regulated TNF-α-induced ROS production in VSMCs. -- Abstract: Atherosclerosis is a chronic inflammation of the coronary arteries. Vascular smooth muscle cells (VSMCs) stimulated by cytokines and chemokines accelerate the inflammatory response and migrate to the injured endothelium during the progression of atherosclerosis. Activation of AMP activated protein kinase (AMPK), a key sensor maintaining metabolic homeostasis, suppresses the inflammatory response. However, how AMPK regulates the inflammatory response is poorly understood. To identify the mechanism of this response, we focused on phosphatase and tensin homolog (PTEN), which is a negative regulator of inflammation. We investigated that activation of AMPK-induced PTEN expression and suppression of the inflammatory response through the AMPK–PTEN pathway in VSMCs. We treated with the well-known AMPK activator metformin to induce PTEN expression. PTEN was induced by metformin (2 mM) and inhibited by compound C (10 μM) and AMPK siRNA. Tumor necrosis factor-alpha (TNF-α) was used to induce inflammation. The inflammatory response was confirmed by cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) expression, and activation of nuclear factor (NF)-κB. Metformin suppressed COX-2 and iNOS mRNA and protein expression dose dependently. Treatment with compound C and bpv (pic) in the presence of metformin, iNOS and COX-2 protein expression increased. NF-κB activation decreased in response to metformin and was restored by inhibiting AMPK and PTEN. Inhibiting AMPK and PTEN restored ROS levels stimulated with TNF-α. Taken together, PTEN could be a possible downstream regulator of AMPK, and the

Effect of healthy aging on renal vascular responses to local cooling and apnea.

Science.gov (United States)

Patel, Hardikkumar M; Mast, Jessica L; Sinoway, Lawrence I; Muller, Matthew D

2013-07-01

Sympathetically mediated renal vasoconstriction may contribute to the pathogenesis of hypertension in older adults, but empirical data in support of this concept are lacking. In 10 young (26 ± 1 yr) and 11 older (67 ± 2 yr) subjects, we quantified acute hemodynamic responses to three sympathoexcitatory stimuli: local cooling of the forehead, cold pressor test (CPT), and voluntary apnea. We hypothesized that all stimuli would increase mean arterial blood pressure (MAP) and renal vascular resistance index (RVRI) and that aging would augment these effects. Beat-by-beat MAP, heart rate (HR), and renal blood flow velocity (from Doppler) were measured in the supine posture, and changes from baseline were compared between groups. In response to 1°C forehead cooling, aging was associated with an augmented MAP (20 ± 3 vs. 6 ± 2 mmHg) and RVRI (35 ± 6 vs. 16 ± 9%) but not HR. In older adults, there was a positive correlation between the cold-induced pressor response and forehead pain (R = 0.726), but this effect was not observed in young subjects. The CPT raised RVRI in both young (56 ± 13%) and older (45 ± 8%) subjects, but this was not different between groups. Relative to baseline, end-expiratory apnea increased RVRI to a similar extent in both young (46 ± 14%) and older (41 ± 9%) subjects. During sympathetic activation, renal vasoconstriction occurred in both groups. Forehead cooling caused an augmented pressor response in older adults that was related to pain perception.

Tofacitinib Ameliorates Murine Lupus and Its Associated Vascular Dysfunction.

Science.gov (United States)

Furumoto, Yasuko; Smith, Carolyne K; Blanco, Luz; Zhao, Wenpu; Brooks, Stephen R; Thacker, Seth G; Abdalrahman, Zarzour; Sciumè, Giuseppe; Tsai, Wanxia L; Trier, Anna M; Nunez, Leti; Mast, Laurel; Hoffmann, Victoria; Remaley, Alan T; O'Shea, John J; Kaplan, Mariana J; Gadina, Massimo

2017-01-01

Dysregulation of innate and adaptive immune responses contributes to the pathogenesis of systemic lupus erythematosus (SLE) and its associated premature vascular damage. No drug to date targets both systemic inflammatory disease and the cardiovascular complications of SLE. Tofacitinib is a JAK inhibitor that blocks signaling downstream of multiple cytokines implicated in lupus pathogenesis. While clinical trials have shown that tofacitinib exhibits significant clinical efficacy in various autoimmune diseases, its role in SLE and the associated vascular pathology remains to be characterized. MRL/lpr lupus-prone mice were administered tofacitinib or vehicle by gavage for 6 weeks (therapeutic arm) or 8 weeks (preventive arm). Nephritis, skin inflammation, serum levels of autoantibodies and cytokines, mononuclear cell phenotype and gene expression, neutrophil extracellular traps (NETs) release, endothelium-dependent vasorelaxation, and endothelial differentiation were compared in treated and untreated mice. Treatment with tofacitinib led to significant improvement in measures of disease activity, including nephritis, skin inflammation, and autoantibody production. In addition, tofacitinib treatment reduced serum levels of proinflammatory cytokines and interferon responses in splenocytes and kidney tissue. Tofacitinib also modulated the formation of NETs and significantly increased endothelium-dependent vasorelaxation and endothelial differentiation. The drug was effective in both preventive and therapeutic strategies. Tofacitinib modulates the innate and adaptive immune responses, ameliorates murine lupus, and improves vascular function. These results indicate that JAK inhibitors have the potential to be beneficial in SLE and its associated vascular damage. © 2016, American College of Rheumatology.

Chronic Stress Improves NO- and Ca2+ Flux-Dependent Vascular Function: A Pharmacological Study

Energy Technology Data Exchange (ETDEWEB)

Bruder-Nascimento, Thiago, E-mail: bruderthiago@usp.br [Departamento de Farmacologia - Instituto de Biociências de Botucatu - Universidade do Estado de São Paulo (UNESP), Botucatu, São Paulo (Brazil); Departamento de Clínica Médica - Faculdade de Medicina de Botucatu - Universidade do Estado de São Paulo (UNESP), Botucatu, São Paulo (Brazil); Campos, Dijon Henrique Salome [Departamento de Clínica Médica - Faculdade de Medicina de Botucatu - Universidade do Estado de São Paulo (UNESP), Botucatu, São Paulo (Brazil)

2015-03-15

Stress is associated with cardiovascular diseases. This study aimed at assessing whether chronic stress induces vascular alterations, and whether these modulations are nitric oxide (NO) and Ca2+ dependent. Wistar rats, 30 days of age, were separated into 2 groups: control (C) and Stress (St). Chronic stress consisted of immobilization for 1 hour/day, 5 days/week, 15 weeks. Systolic blood pressure was assessed. Vascular studies on aortic rings were performed. Concentration-effect curves were built for noradrenaline, in the presence of L-NAME or prazosin, acetylcholine, sodium nitroprusside and KCl. In addition, Ca{sup 2+} flux was also evaluated. Chronic stress induced hypertension, decreased the vascular response to KCl and to noradrenaline, and increased the vascular response to acetylcholine. L-NAME blunted the difference observed in noradrenaline curves. Furthermore, contractile response to Ca{sup 2+} was decreased in the aorta of stressed rats. Our data suggest that the vascular response to chronic stress is an adaptation to its deleterious effects, such as hypertension. In addition, this adaptation is NO- and Ca{sup 2+}-dependent. These data help to clarify the contribution of stress to cardiovascular abnormalities. However, further studies are necessary to better elucidate the mechanisms involved in the cardiovascular dysfunction associated with stressors. (Arq Bras Cardiol. 2014; [online].ahead print, PP.0-0)

The effect of nucleotides and adenosine on stimulus-evoked glutamate release from rat brain cortical slices.

Science.gov (United States)

Bennett, G C; Boarder, M R

2000-10-01

Evidence has previously been presented that P1 receptors for adenosine, and P2 receptors for nucleotides such as ATP, regulate stimulus-evoked release of biogenic amines from nerve terminals in the brain. Here we investigated whether adenosine and nucleotides exert presynaptic control over depolarisation-elicited glutamate release. Slices of rat brain cortex were perfused and stimulated with pulses of 46 mM K(+) in the presence of the glutamate uptake inhibitor L-trans-pyrrolidine-2,4-dicarboxylic acid (0.2 mM). High K(+) substantially increased efflux of glutamate from the slices. Basal glutamate release was unchanged by the presence of nucleotides or adenosine at concentrations of 300 microM. Adenosine, ATP, ADP and adenosine 5'-O-(3-thiotriphoshate) at 300 microM attenuated depolarisation-evoked release of glutamate. However UTP, 2-methylthio ATP, 2-methylthio ADP, and alpha,beta-methylene ATP at 300 microM had no effect on stimulated glutamate efflux. Adenosine deaminase blocked the effect of adenosine, but left the response to ATP unchanged. The A(1) antagonist 8-cyclopentyl-1, 3-dipropylxanthine antagonised the inhibitory effect of both adenosine and ATP. Cibacron blue 3GA inhibited stimulus-evoked glutamate release when applied alone. When cibacron blue 3GA was present with ATP, stimulus-evoked glutamate release was almost eliminated. However, this P2 antagonist had no effect on the inhibition by adenosine. These results show that the release of glutamate from depolarised nerve terminals of the rat cerebral cortex is inhibited by adenosine and ATP. ATP appears to act directly and not through conversion to adenosine.

Do Puzzle Pieces and Autism Puzzle Piece Logos Evoke Negative Associations?

Science.gov (United States)

Gernsbacher, Morton Ann; Raimond, Adam R.; Stevenson, Jennifer L.; Boston, Jilana S.; Harp, Bev

2018-01-01

Puzzle pieces have become ubiquitous symbols for autism. However, puzzle-piece imagery stirs debate between those who support and those who object to its use because they believe puzzle-piece imagery evokes negative associations. Our study empirically investigated whether puzzle pieces evoke negative associations in the general public.…

Multifunctional silk-heparin biomaterials for vascular tissue engineering applications

Science.gov (United States)

Seib, F. Philipp; Herklotz, Manuela; Burke, Kelly A.; Maitz, Manfred F.; Werner, Carsten; Kaplan, David L.

2013-01-01

Over the past 30 years, silk has been proposed for numerous biomedical applications that go beyond its traditional use as a suture material. Silk sutures are well tolerated in humans, but the use of silk for vascular engineering applications still requires extensive biocompatibility testing. Some studies have indicated a need to modify silk to yield a hemocompatible surface. This study examined the potential of low molecular weight heparin as a material for refining silk properties by acting as a carrier for vascular endothelial growth factor (VEGF) and improving silk hemocompatibility. Heparinized silk showed a controlled VEGF release over 6 days; the released VEGF was bioactive and supported the growth of human endothelial cells. Silk samples were then assessed using a humanized hemocompatibility system that employs whole blood and endothelial cells. The overall thrombogenic response for silk was very low and similar to the clinical reference material polytetrafluoroethylene. Despite an initial inflammatory response to silk, apparent as complement and leukocyte activation, the endothelium was maintained in a resting, anticoagulant state. The low thrombogenic response and the ability to control VEGF release support the further development of silk for vascular applications. PMID:24099708

Development of the complex general linear model in the Fourier domain: application to fMRI multiple input-output evoked responses for single subjects.

Science.gov (United States)

Rio, Daniel E; Rawlings, Robert R; Woltz, Lawrence A; Gilman, Jodi; Hommer, Daniel W

2013-01-01

A linear time-invariant model based on statistical time series analysis in the Fourier domain for single subjects is further developed and applied to functional MRI (fMRI) blood-oxygen level-dependent (BOLD) multivariate data. This methodology was originally developed to analyze multiple stimulus input evoked response BOLD data. However, to analyze clinical data generated using a repeated measures experimental design, the model has been extended to handle multivariate time series data and demonstrated on control and alcoholic subjects taken from data previously analyzed in the temporal domain. Analysis of BOLD data is typically carried out in the time domain where the data has a high temporal correlation. These analyses generally employ parametric models of the hemodynamic response function (HRF) where prewhitening of the data is attempted using autoregressive (AR) models for the noise. However, this data can be analyzed in the Fourier domain. Here, assumptions made on the noise structure are less restrictive, and hypothesis tests can be constructed based on voxel-specific nonparametric estimates of the hemodynamic transfer function (HRF in the Fourier domain). This is especially important for experimental designs involving multiple states (either stimulus or drug induced) that may alter the form of the response function.

Redox Signaling and Its Impact on Skeletal and Vascular Responses to Spaceflight

Directory of Open Access Journals (Sweden)

Candice G. T. Tahimic

2017-10-01

Full Text Available Spaceflight entails exposure to numerous environmental challenges with the potential to contribute to both musculoskeletal and vascular dysfunction. The purpose of this review is to describe current understanding of microgravity and radiation impacts on the mammalian skeleton and associated vasculature at the level of the whole organism. Recent experiments from spaceflight and ground-based models have provided fresh insights into how these environmental stresses influence mechanisms that are related to redox signaling, oxidative stress, and tissue dysfunction. Emerging mechanistic knowledge on cellular defenses to radiation and other environmental stressors, including microgravity, are useful for both screening and developing interventions against spaceflight-induced deficits in bone and vascular function.

Redox Signaling and Its Impact on Skeletal and Vascular Responses to Spaceflight

Science.gov (United States)

Tahimic, Candice; Globus, Ruth K.

2018-01-01

Spaceflight entails exposure to numerous environmental challenges with the potential to contribute to both musculoskeletal and vascular dysfunction. The purpose of this review is to describe current understanding of microgravity and radiation impacts on the mammalian skeleton and associated vasculature at the level of the whole organism. Recent experiments from spaceflight and groundbased models have provided fresh insights into how these environmental stresses influence mechanisms that are related to redox signaling, oxidative stress, and tissue dysfunction. Emerging mechanistic knowledge on cellular defenses to radiation and other environmental stressors, including microgravity, are useful for both screening and developing interventions against spaceflight-induced deficits in bone and vascular function.

Language performance and auditory evoked fields in 2- to 5-year-old children.

Science.gov (United States)

Yoshimura, Yuko; Kikuchi, Mitsuru; Shitamichi, Kiyomi; Ueno, Sanae; Remijn, Gerard B; Haruta, Yasuhiro; Oi, Manabu; Munesue, Toshio; Tsubokawa, Tsunehisa; Higashida, Haruhiro; Minabe, Yoshio

2012-02-01

Language development progresses at a dramatic rate in preschool children. As rapid temporal processing of speech signals is important in daily colloquial environments, we performed magnetoencephalography (MEG) to investigate the linkage between speech-evoked responses during rapid-rate stimulus presentation (interstimulus interval language performance in 2- to 5-year-old children (n = 59). Our results indicated that syllables with this short stimulus interval evoked detectable P50m, but not N100m, in most participants, indicating a marked influence of longer neuronal refractory period for stimulation. The results of equivalent dipole estimation showed that the intensity of the P50m component in the left hemisphere was positively correlated with language performance (conceptual inference ability). The observed positive correlations were suggested to reflect the maturation of synaptic organisation or axonal maturation and myelination underlying the acquisition of linguistic abilities. The present study is among the first to use MEG to study brain maturation pertaining to language abilities in preschool children. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

The cellular response to vascular endothelial growth factors requires co-ordinated signal transduction, trafficking and proteolysis.

Science.gov (United States)

Smith, Gina A; Fearnley, Gareth W; Tomlinson, Darren C; Harrison, Michael A; Ponnambalam, Sreenivasan

2015-08-18

VEGFs (vascular endothelial growth factors) are a family of conserved disulfide-linked soluble secretory glycoproteins found in higher eukaryotes. VEGFs mediate a wide range of responses in different tissues including metabolic homoeostasis, cell proliferation, migration and tubulogenesis. Such responses are initiated by VEGF binding to soluble and membrane-bound VEGFRs (VEGF receptor tyrosine kinases) and co-receptors. VEGF and receptor splice isoform diversity further enhances complexity of membrane protein assembly and function in signal transduction pathways that control multiple cellular responses. Different signal transduction pathways are simultaneously activated by VEGFR-VEGF complexes with membrane trafficking along the endosome-lysosome network further modulating signal output from multiple enzymatic events associated with such pathways. Balancing VEGFR-VEGF signal transduction with trafficking and proteolysis is essential in controlling the intensity and duration of different intracellular signalling events. Dysfunction in VEGF-regulated signal transduction is important in chronic disease states including cancer, atherosclerosis and blindness. This family of growth factors and receptors is an important model system for understanding human disease pathology and developing new therapeutics for treating such ailments. © 2015 Authors.

Oxidative and inflammatory signals in obesity-associated vascular abnormalities.

Science.gov (United States)

Reho, John J; Rahmouni, Kamal

2017-07-15

Obesity is associated with increased cardiovascular morbidity and mortality in part due to vascular abnormalities such as endothelial dysfunction and arterial stiffening. The hypertension and other health complications that arise from these vascular defects increase the risk of heart diseases and stroke. Prooxidant and proinflammatory signaling pathways as well as adipocyte-derived factors have emerged as critical mediators of obesity-associated vascular abnormalities. Designing treatments aimed specifically at improving the vascular dysfunction caused by obesity may provide an effective therapeutic approach to prevent the cardiovascular sequelae associated with excessive adiposity. In this review, we discuss the recent evidence supporting the role of oxidative stress and cytokines and inflammatory signals within the vasculature as well as the impact of the surrounding perivascular adipose tissue (PVAT) on the regulation of vascular function and arterial stiffening in obesity. In particular, we focus on the highly plastic nature of the vasculature in response to altered oxidant and inflammatory signaling and highlight how weight management can be an effective therapeutic approach to reduce the oxidative stress and inflammatory signaling and improve vascular function. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Oscillatory frontal theta responses are increased upon bisensory stimulation.

Science.gov (United States)

Sakowitz, O W; Schürmann, M; Başar, E

2000-05-01

To investigate the functional correlation of oscillatory EEG components with the interaction of sensory modalities following simultaneous audio-visual stimulation. In an experimental study (15 subjects) we compared auditory evoked potentials (AEPs) and visual evoked potentials (VEPs) to bimodal evoked potentials (BEPs; simultaneous auditory and visual stimulation). BEPs were assumed to be brain responses to complex stimuli as a marker for intermodal associative functioning. Frequency domain analysis of these EPs showed marked theta-range components in response to bimodal stimulation. These theta components could not be explained by linear addition of the unimodal responses in the time domain. Considering topography the increased theta-response showed a remarkable frontality in proximity to multimodal association cortices. Referring to methodology we try to demonstrate that, even if various behavioral correlates of brain oscillations exist, common patterns can be extracted by means of a systems-theoretical approach. Serving as an example of functionally relevant brain oscillations, theta responses could be interpreted as an indicator of associative information processing.

Regulation of capacitative and non-capacitative Ca2+ entry in A7r5 vascular smooth muscle cells

Directory of Open Access Journals (Sweden)

COLIN W TAYLOR

2004-01-01

Full Text Available A capacitative Ca2+ entry (CCE pathway, activated by depletion of intracellular Ca2+ stores, is thought to mediate much of the Ca2+ entry evoked by receptors that stimulate phospholipase C (PLC. However, in A7r5 vascular smooth muscle cells, vasopressin, which stimulates PLC, empties intracellular Ca2+ stores but simultaneously inhibits their ability to activate CCE. The diacylglycerol produced with the IP3 that empties the stores is metabolized to arachidonic and this leads to activation of nitric oxide (NO synthase, production of NO and cyclic GMP, and consequent activation of protein kinase G. The latter inhibits CCE. In parallel, NO directly activates a non-capacitative Ca2+ entry (NCCE pathway, which is entirely responsible for the Ca2+ entry that occurs in the presence of vasopressin. This reciprocal regulation of two Ca2+ entry pathways ensures that there is sequential activation of first NCCE in the presence of vasopressin, and then a transient activation of CCE when vasopressin is removed. We suggest that the two routes for Ca2+ entry may selectively direct Ca2+ to processes that mediate activation and then recovery of the cell.

Evoked potentials in pediatric cerebral malaria

Directory of Open Access Journals (Sweden)

Minal Bhanushali

2011-12-01

Full Text Available Cortical evoked potentials (EP provide localized data regarding brain function and may offer prognostic information and insights into the pathologic mechanisms of malariamediated cerebral injury. As part of a prospective cohort study, we obtained somatosensory evoked potentials (SSEPs and brainstem auditory EPs (AEPs within 24 hours of admission on 27 consecutive children admitted with cerebral malaria (CM. Children underwent follow-up for 12 months to determine if they had any long term neurologic sequelae. EPs were obtained in 27 pediatric CM admissions. Two children died. Among survivors followed an average of 514 days, 7/25 (28.0% had at least one adverse neurologic outcome. Only a single subject had absent cortical EPs on admission and this child had a good neurologic outcome. Among pediatric CM survivors, cortical EPs are generally intact and do not predict adverse neurologic outcomes. Further study is needed to determine if alterations in cortical EPs can be used to predict a fatal outcome in CM.

Direct detection of a single evoked action potential with MRS in Lumbricus terrestris.

Science.gov (United States)

Poplawsky, Alexander J; Dingledine, Raymond; Hu, Xiaoping P

2012-01-01

Functional MRI (fMRI) measures neural activity indirectly by detecting the signal change associated with the hemodynamic response following brain activation. In order to alleviate the temporal and spatial specificity problems associated with fMRI, a number of attempts have been made to detect neural magnetic fields (NMFs) with MRI directly, but have thus far provided conflicting results. In this study, we used MR to detect axonal NMFs in the median giant fiber of the earthworm, Lumbricus terrestris, by examining the free induction decay (FID) with a sampling interval of 0.32 ms. The earthworm nerve cords were isolated from the vasculature and stimulated at the threshold of action potential generation. FIDs were acquired shortly after the stimulation, and simultaneous field potential recordings identified the presence or absence of single evoked action potentials. FIDs acquired when the stimulus did not evoke an action potential were summed as background. The phase of the background-subtracted FID exhibited a systematic change, with a peak phase difference of (-1.2 ± 0.3) × 10(-5) radians occurring at a time corresponding to the timing of the action potential. In addition, we calculated the possible changes in the FID magnitude and phase caused by a simulated action potential using a volume conductor model. The measured phase difference matched the theoretical prediction well in both amplitude and temporal characteristics. This study provides the first evidence for the direct detection of a magnetic field from an evoked action potential using MR. Copyright © 2011 John Wiley & Sons, Ltd.

Defibrotide modulates prostaglandin production in the rat mesenteric vascular bed.

Science.gov (United States)

Peredo, H A

2002-10-01

Defibrotide 1 microM, a polydeoxyribonucleotide extracted from mammalian organs, reduced the contractile responses to noradrenaline (NA) in the rat isolated and perfused mesenteric vascular bed, in intact as well as in de-endothelialized preparations. Defibrotide was without effect on the acetylcholine-induced relaxations of U-46619-precontracted mesenteric vascular beds. Moreover, defibrotide increased 6-keto prostaglandin (PG) F(2alpha) (stable metabolite of prostacyclin) release sixfold in the presence, but not in the absence of the endothelium, with no modification on the release of other prostanoids. Defibrotide also inhibited the NA-induced increase in PGF(2alpha) release, in both intact and de-endothelialized mesenteric vascular beds. In conclusion, the present results show that defibrotide modulates PG production in the mesenteric bed and that the observed inhibition of the contractile responses should be due to the impairment of the NA-induced increase in PGF(2alpha) release.

Laser-evoked coloration in polymers

International Nuclear Information System (INIS)

Zheng, H.Y.; Rosseinsky, David; Lim, G.C.

2005-01-01

Laser-evoked coloration in polymers has long been a major aim of polymer technology for potential applications in product surface decoration, marking personalised images and logos. However, the coloration results reported so far were mostly attributed to laser-induced thermal-chemical reactions. The laser-irradiated areas are characterized with grooves due to material removal. Furthermore, only single color was laser-induced in any given polymer matrix. To induce multiple colors in a given polymer matrix with no apparent surface material removal is most desirable and challenging and may be achieved through laser-induced photo-chemical reactions. However, little public information is available at present. We report that two colors of red and green have been produced on an initially transparent CPV/PVA samples through UV laser-induced photo-chemical reactions. This is believed the first observation of laser-induced multiple-colors in the given polymer matrix. It is believed that the colorants underwent photo-effected electron transfer with suitable electron donors from the polymers to change from colorless bipyridilium Bipm 2+ to the colored Bipm + species. The discovery may lead to new approaches to the development of laser-evoked multiple coloration in polymers

Visual evoked potentials in neuromyelitis optica and its spectrum disorders.

Science.gov (United States)

Ringelstein, Marius; Kleiter, Ingo; Ayzenberg, Ilya; Borisow, Nadja; Paul, Friedemann; Ruprecht, Klemens; Kraemer, Markus; Cohn, Eva; Wildemann, Brigitte; Jarius, Sven; Hartung, Hans-Peter; Aktas, Orhan; Albrecht, Philipp

2014-04-01

Optic neuritis (ON) is a key feature of neuromyelitis optica (NMO). Recently, NMO patients of predominantly Afro-Brazilian origin were evaluated by visual evoked potentials (VEPs) and showed marked amplitude reductions. Here, we analyzed VEPs in a predominantly Caucasian cohort, consisting of 43 patients with definite NMO, 18 with anti-aquaporin (AQP) 4 antibody-seropositive NMO spectrum disorders and 61 matched healthy controls. We found reduced amplitudes in only 12.3%, prolonged latencies in 41.9% and a lack of response in 14.0% of NMO eyes. Delayed P100 latencies in eyes without prior ON suggested this was a subclinical affection. The data indicate heterogenous patterns in NMO, warranting further investigation.

Brain Activity Associated with Slow Temporal Summation of C-fiber Evoked Pain in Fibromyalgia Patients and Healthy Controls

OpenAIRE

Staud, Roland; Craggs, Jason G.; Perlstein, William M.; Robinson, Michael E.; Price, Donald D.

2008-01-01

Temporal summation of “second pain” (TSSP) is the result of C-fiber-evoked responses of dorsal-horn neurons, termed ‘windup’. This phenomenon is dependent on stimulus frequency (≥0.33 Hz) and relevant for central sensitization as well as chronic pain. Whereas our previous functional magnetic resonance imaging (fMRI) study characterized neural correlates of TSSP in eleven healthy volunteers, the present study was designed to compare brain responses associated with TSSP across these healthy par...

Vestibular-Evoked Myogenic Potentials in Bilateral Vestibulopathy

Directory of Open Access Journals (Sweden)

Sally M. Rosengren

2018-04-01

Full Text Available Bilateral vestibulopathy (BVP is a chronic condition in which patients have a reduction or absence of vestibular function in both ears. BVP is characterized by bilateral reduction of horizontal canal responses; however, there is increasing evidence that otolith function can also be affected. Cervical and ocular vestibular-evoked myogenic potentials (cVEMPs/oVEMPs are relatively new tests of otolith function that can be used to test the saccule and utricle of both ears independently. Studies to date show that cVEMPs and oVEMPs are often small or absent in BVP but are in the normal range in a significant proportion of patients. The variability in otolith function is partly due to the heterogeneous nature of BVP but is also due to false negative and positive responses that occur because of the large range of normal VEMP amplitudes. Due to their variability, VEMPs are not part of the diagnosis of BVP; however, they are helpful complementary tests that can provide information about the extent of disease within the labyrinth. This article is a review of the use of VEMPs in BVP, summarizing the available data on VEMP abnormalities in patients and discussing the limitations of VEMPs in diagnosing bilateral loss of otolith function.

Study on change of multi-modally evoked potentials in nasopharyngeal carcinoma patients after radiotherapy

International Nuclear Information System (INIS)

Qin Ling; Chen Jiaxin; Zhang Lixiang; Wang Tiejian; Han Min; Lu Xiaoling

2001-01-01

Objective: To investigate possible changes of multi-modally evoked potentials in nasopharyngeal carcinoma patients after radiotherapy. Methods: Altogether 48 nasopharyngeal carcinoma patients receiving primary conventional external beam irradiation were examined before and after radiotherapy to determine their brainstem auditory-evoked potential (BAEP), short-latency somatosensory-evoked potential (SLSEP) and pattern reversal visual-evoked potential (PRVEP). Results: In comparison with the conditions before radiotherapy, in different periods after radiotherapy abnormal peak latency and interval latency difference were found in BAEP, SLSEP and PRVEP. Conclusion: Nasopharyngeal carcinoma after radiotherapy may cause abnormal function of nerve conduction in early periods, which can be showed by BAEP, SLSEP, PRVEP, and injury can be timely detected if the three evoked potentials are used together. Thus authors suggest BAEP, SLSEP, PRVEP should be examined in nasopharyngeal carcinoma patients during and after the radiotherapy so as to find early damage in auditory somatosensory and visual conduction pathways

Differential vascular dysfunction in response to diets of differing macronutrient composition: a phenomenonological study

Directory of Open Access Journals (Sweden)

Cassidy Roslyn

2007-06-01

Full Text Available Abstract Background Vascular dysfunction can develop from consumption of an energy-rich diet, even prior to the onset of obesity. However, the roles played by different dietary components remain uncertain. While attempting to develop models of obesity in a separate study, we observed that two high-energy diets of differing macronutrient compositions affected vascular function differently in overweight rats. Methods Male Wistar rats (n = 6/group were fed diets providing varying percentages of energy from fat and carbohydrate (CHO. For 10 weeks, they were fed either chow, as control diet (10% of energy from fat; 63% from CHO, chow supplemented with chocolate biscuit (30% fat; 56% CHO or a high-fat diet (45% fat; 35% CHO. Blood concentrations of biochemical markers of obesity were measured, and epididymal fat pads weighed as a measure of adiposity. Mesenteric arteries were dissected and their contractile and relaxant properties analysed myographically. Data were tested by analysis of variance (ANOVA. Results Weight gain and plasma concentrations of glucose, insulin and leptin were similar in all groups. However, biscuit-fed animals showed increased food intake (+27%; p p p p p Conclusion Vascular dysfunction resulting from consumption of a high-fat or combined relatively high-fat/high-CHO diet occurs through different physiological processes, which may be attributable to their differing macronutrient compositions. Combining potentially atherogenic macronutrients induces more extensive vascular impairment than that of high-fat alone, and may be attributable to the more marked dyslipidaemia observed with such a diet. Thus, these findings help clarify the role of dietary components in vascular impairment, which has implications for clinical approaches to preventing cardiovascular disease.

Comparative vascular responses three months after paclitaxel and everolimus-eluting stent implantation in streptozotocin-induced diabetic porcine coronary arteries

Directory of Open Access Journals (Sweden)

Sheehy Alexander

2012-06-01

Full Text Available Abstract Background Diabetes remains a significant risk factor for restenosis/thrombosis following stenting. Although vascular healing responses following drug-eluting stent (DES treatment have been characterized previously in healthy animals, comparative assessments of different DES in a large animal model with isolated features of diabetes remains limited. We aimed to comparatively assess the vascular response to paclitaxel-eluting (PES and everolimus-eluting (EES stents in a porcine coronary model of streptozotocin (STZ-induced type I diabetes. Method Twelve Yucatan swine were induced hyperglycemic with a single STZ dose intravenously to ablate pancreatic β-cells. After two months, each animal received one XIENCE V® (EES and one Taxus Liberte (PES stent, respectively, in each coronary artery. After three months, vascular healing was assessed by angiography and histomorphometry. Comparative in vitro effects of everolimus and paclitaxel (10-5 M–10-12 M after 24 hours on carotid endothelial (EC and smooth muscle (SMC cell viability under hyperglycemic (42 mM conditions were assayed by ELISA. Caspase-3 fluorescent assay was used to quantify caspase-3 activity of EC treated with everolimus or paclitaxel (10-5 M, 10-7 M for 24 hours. Results After 3 months, EES reduced neointimal area (1.60 ± 0.41 mm, p vs. 0.08 ± 0.05, greater medial necrosis grade (0.52 ± 0.26 vs. 0.0 ± 0.0, and persistently elevated fibrin scores (1.60 ± 0.60 vs. 0.63 ± 0.41 with PES compared to EES (p In vitro, paclitaxel significantly increased (p -7 M, while everolimus did not affect EC/SMC apoptosis/necrosis within the dose range tested. In ECs, paclitaxel (10-5 M significantly increased caspase-3 activity (p  Conclusion After 3 months, both DES exhibited signs of delayed healing in a STZ-induced diabetic swine model. PES exhibited greater neointimal area, increased inflammation, greater medial necrosis, and

Metformin inhibits inflammatory response via AMPK-PTEN pathway in vascular smooth muscle cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Sun Ae [Department of Pharmacology, Aging-Associated Vascular Disease Research Center, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Choi, Hyoung Chul, E-mail: hcchoi@med.yu.ac.kr [Department of Pharmacology, Aging-Associated Vascular Disease Research Center, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of)

2012-09-07

Highlights: Black-Right-Pointing-Pointer PTEN was induced by metformin and inhibited by compound C and AMPK siRNA. Black-Right-Pointing-Pointer Metformin suppressed TNF-{alpha}-induced COX-2 and iNOS mRNA expression. Black-Right-Pointing-Pointer Compound C and bpv (pic) increased iNOS and COX-2 protein expression. Black-Right-Pointing-Pointer NF-{kappa}B activation was restored by inhibiting AMPK and PTEN. Black-Right-Pointing-Pointer AMPK and PTEN regulated TNF-{alpha}-induced ROS production in VSMCs. -- Abstract: Atherosclerosis is a chronic inflammation of the coronary arteries. Vascular smooth muscle cells (VSMCs) stimulated by cytokines and chemokines accelerate the inflammatory response and migrate to the injured endothelium during the progression of atherosclerosis. Activation of AMP activated protein kinase (AMPK), a key sensor maintaining metabolic homeostasis, suppresses the inflammatory response. However, how AMPK regulates the inflammatory response is poorly understood. To identify the mechanism of this response, we focused on phosphatase and tensin homolog (PTEN), which is a negative regulator of inflammation. We investigated that activation of AMPK-induced PTEN expression and suppression of the inflammatory response through the AMPK-PTEN pathway in VSMCs. We treated with the well-known AMPK activator metformin to induce PTEN expression. PTEN was induced by metformin (2 mM) and inhibited by compound C (10 {mu}M) and AMPK siRNA. Tumor necrosis factor-alpha (TNF-{alpha}) was used to induce inflammation. The inflammatory response was confirmed by cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) expression, and activation of nuclear factor (NF)-{kappa}B. Metformin suppressed COX-2 and iNOS mRNA and protein expression dose dependently. Treatment with compound C and bpv (pic) in the presence of metformin, iNOS and COX-2 protein expression increased. NF-{kappa}B activation decreased in response to metformin and was restored by inhibiting AMPK

Index finger somatosensory evoked potentials in blind Braille readers.

Science.gov (United States)

Giriyappa, Dayananda; Subrahmanyam, Roopakala Mysore; Rangashetty, Srinivasa; Sharma, Rajeev

2009-01-01

Traditionally, vision has been considered the dominant modality in our multi-sensory perception of the surrounding world. Sensory input via non-visual tracts becomes of greater behavioural relevance in totally blind individuals to enable effective interaction with the world around them. These include audition and tactile perceptions, leading to an augmentation in these perceptions when compared with normal sighted individuals. The objective of the present work was to study the index finger somatosensory evoked potentials (SEPs) in totally blind and normal sighted individuals. SEPs were recorded in 15 Braille reading totally blind females and compared with 15 age-matched normal sighted females. Latency and amplitudes of somatosensory evoked potential waveforms (N9, N13, and N20) were measured. Amplitude of N20 SEP (a cortical somatosensory evoked potential) was significantly larger in the totally blind than in normal sighted individuals (p Braille reading right index finger. Totally blind Braille readers have larger N20 amplitude, suggestive of greater somatosensory cortical representation of the Braille reading index finger.

Effects of age and caloric restriction in the vascular response of renal arteries to endothelin-1 in rats.

Science.gov (United States)

Amor, Sara; García-Villalón, Angel Luis; Rubio, Carmen; Carrascosa, Jose Ma; Monge, Luis; Fernández, Nuria; Martín-Carro, Beatriz; Granado, Miriam

2017-02-01

Cardiovascular alterations are the most prevalent cause of impaired physiological function in aged individuals with kidney being one the most affected organs. Aging-induced alterations in renal circulation are associated with a decrease in endothelium-derived relaxing factors such as nitric oxide (NO) and with an increase in contracting factors such as endothelin-1(ET-1). As caloric restriction (CR) exerts beneficial effects preventing some of the aging-induced alterations in cardiovascular system, the aim of this study was to analyze the effects of age and caloric restriction in the vascular response of renal arteries to ET-1 in aged rats. Vascular function was studied in renal arteries from 3-month-old Wistar rats fed ad libitum (3m) and in renal arteries from 8-and 24-month-old Wistar rats fed ad libitum (8m and 24m), or subjected to 20% caloric restriction during their three last months of life (8m-CR and 24m-CR). The contractile response to ET-1 was increased in renal arteries from 8m and 24m compared to 3m rats. ET-1-induced contraction was mediated by ET-A receptors in all experimental groups and also by ET-B receptors in 24m rats. Caloric restriction attenuated the increased contraction to ET-1 in renal arteries from 8m but not from 24m rats possibly through NO release proceeding from ET-B endothelial receptors. In 24m rats, CR did not attenuate the aging-increased response of renal arteries to ET-1, but it prevented the aging-induced increase in iNOS mRNA levels and the aging-induced decrease in eNOS mRNA levels in arterial tissue. In conclusion, aging is associated with an increased response to ET-1 in renal arteries that is prevented by CR in 8m but not in 24m rats. Copyright © 2016 Elsevier Inc. All rights reserved.

Activity-Dependent Calcium, Oxygen, and Vascular Responses in a Mouse Model of Familial Hemiplegic Migraine Type 1

DEFF Research Database (Denmark)

Khennouf, Lila; Gesslein, Bodil; Lind, Barbara Lykke

2016-01-01

it with assessment of local field potentials by electrophysiological recordings, cerebral blood flow by laser Doppler flowmetry, and oxygen consumption with measurement of the oxygen tissue tension. Results: During spreading depression, the evoked increase in cytosolic Ca2+ was larger and faster in FHM1 mice than...... wild-type (WT) mice. It was accompanied by larger increases in oxygen consumption in FHM1 mice, leading to tissue anoxia, but moderate hypoxia, in WT mice. In comparison, before CSD, Ca2+ and hemodynamic responses to somatosensory stimulations were smaller in FHM1 mice than WT mice and almost abolished...... after CSD. The CSD-induced Ca2+ changes were mitigated by the CaV2.1 gating modifier, tert-butyl dihydroquinone. Interpretation: Our findings suggest that tissue anoxia might be a mechanism for prolonged aura in FHM1. Reduced Ca2+ signals during normal network activity in FHM1 as compared to WT mice may...

Acupuncture-like stimulation at auricular point Heart evokes cardiovascular inhibition via activating the cardiac-related neurons in the nucleus tractus solitarius.

Science.gov (United States)

Gao, Xin Yan; Li, Yan Hua; Liu, Kun; Rong, Pei Jing; Ben, Hui; Li, Liang; Zhu, Bing; Zhang, Shi Ping

2011-06-23

Fifty-eight male Sprague-Dawley rats used in the present study to investigate the role of baroreceptor sensitive neurons of the nucleus tractus solitarius (NTS) in the regulation of cardiovascular inhibition during acupuncture at the auricular point Heart, single unit recording was made in anesthetized Sprague-Dawley rats. A neuron was considered to be excited or inhibited by acupuncture stimulation if it displayed 15% more or less spikes s(-1), respectively. NTS neurons were classified into cardiac-related (CR) neurons and non-cardiac-related neurons based on whether their rhythmic discharges were synchronized with the R-waves and responding to sodium nitroprusside (NP; 20 μg/kg, i.v.) administration. Manual acupuncture was applied at the auricular point Heart and somatic acupuncture points ST36 and PC6. Acupuncture at auricular point Heart showed a more significant inhibitory effect on arterial pressure (-22.1±2.4mm Hg; Pheart rate (-12.7±1.7 bpm; PHeart also increased the level of response of CR neurons in the NTS (93.8%±26.0% increase in discharge rate; Pneurons evoked by auricular acupuncture, but had no effect on the same responses evoked by somatic acupuncture. Inactivation of the NTS with local anesthetics also decreased the cardiovascular inhibitory responses evoked by auricular acupuncture. Our results show that acupuncture at the auricular point Heart regulates cardiovascular function by activating baroreceptor sensitive neurons in the NTS in a similar manner as the baroreceptor reflex in cardiovascular inhibition. Copyright © 2011 Elsevier B.V. All rights reserved.

Sensing of Vascular Permeability in Inflamed Vessel of Live Animal

Directory of Open Access Journals (Sweden)

Sang A Park

2018-01-01

Full Text Available Increase in vascular permeability is a conclusive response in the progress of inflammation. Under controlled conditions, leukocytes are known to migrate across the vascular barriers to the sites of inflammation without severe vascular rupture. However, when inflammatory state becomes excessive, the leakage of blood components may occur and can be lethal. Basically, vascular permeability can be analyzed based on the intensity of blood outflow. To evaluate the amount and rate of leakage in live mice, we performed cremaster muscle exteriorization to visualize blood flow and neutrophil migration. Using two-photon intravital microscopy of the exteriorized cremaster muscle venules, we found that vascular barrier function is transiently and locally disrupted in the early stage of inflammatory condition induced by N-formylmethionyl-leucyl-phenylalanine (fMLP. Measurement of the concentration of intravenously (i.v. injected Texas Red dextran inside and outside the vessels resulted in clear visualization of real-time increases in transient and local vascular permeability increase in real-time manner. We successfully demonstrated repeated leakage from a target site on a blood vessel in association with increasing severity of inflammation. Therefore, compared to other methods, two-photon intravital microscopy more accurately visualizes and quantifies vascular permeability even in a small part of blood vessels in live animals in real time.

Sex differences in the jealousy-evoking nature of a rival's body build

NARCIS (Netherlands)

Dijkstra, Pieternel; Buunk, Abraham (Bram)

This study among 185 college students showed that potential rivals with a relatively low waist-to-hip ratio (WHR) evoked more jealousy in women than in men. In contrast, rivals with a relatively high shoulder-to-hip ratio (SHR) evoked more jealousy in men than in women, particularly when the rival

Initial evaluation of vascular ingrowth into superporous hydrogels.

Science.gov (United States)

Keskar, Vandana; Gandhi, Milind; Gemeinhart, Ernest J; Gemeinhart, Richard A

2009-08-01

There is a need for new materials and architectures for tissue engineering and regenerative medicine. Based upon our recent results developing novel scaffold architecture, we hypothesized that this new architecture would foster vascularization, a particular need for tissue engineering. We report on the potential of superporous hydrogel (SPH) scaffolds for in vivo cellular infiltration and vascularization. Poly(ethylene glycol) diacrylate (PEGDA) SPH scaffolds were implanted in the dorsum of severe combined immunodeficient (SCID) mice and harvested after 4 weeks of in vivo implantation. The SPHs were visibly red and vascularized, as apparent when compared to the non-porous hydrogel controls, which were macroscopically avascular. Host cell infiltration was observed throughout the SPHs. Blood cells and vascular structures, confirmed through staining for CD34 and smooth muscle alpha-actin, were observed throughout the scaffolds. This novel soft material may be utilized for cell transplantation, tissue engineering and in combination with cell therapies. The neovasularization and limited fibrotic response suggest that the architecture may be conducive to cell survival and rapid vessel development.

Optogenetic activation of CA1 pyramidal neurons at the dorsal and ventral hippocampus evokes distinct brain-wide responses revealed by mouse fMRI.

Directory of Open Access Journals (Sweden)

Norio Takata

Full Text Available The dorsal and ventral hippocampal regions (dHP and vHP are proposed to have distinct functions. Electrophysiological studies have revealed intra-hippocampal variances along the dorsoventral axis. Nevertheless, the extra-hippocampal influences of dHP and vHP activities remain unclear. In this study, we compared the spatial distribution of brain-wide responses upon dHP or vHP activation and further estimate connection strengths between the dHP and the vHP with corresponding extra-hippocampal areas. To achieve this, we first investigated responses of local field potential (LFP and multi unit activities (MUA upon light stimulation in the hippocampus of an anesthetized transgenic mouse, whose CA1 pyramidal neurons expressed a step-function opsin variant of channelrhodopsin-2 (ChR2. Optogenetic stimulation increased hippocampal LFP power at theta, gamma, and ultra-fast frequency bands, and augmented MUA, indicating light-induced activation of CA1 pyramidal neurons. Brain-wide responses examined using fMRI revealed that optogenetic activation at the dHP or vHP caused blood oxygenation level-dependent (BOLD fMRI signals in situ. Although activation at the dHP induced BOLD responses at the vHP, the opposite was not observed. Outside the hippocampal formation, activation at the dHP, but not the vHP, evoked BOLD responses at the retrosplenial cortex (RSP, which is in line with anatomical evidence. In contrast, BOLD responses at the lateral septum (LS were induced only upon vHP activation, even though both dHP and vHP send axonal fibers to the LS. Our findings suggest that the primary targets of dHP and vHP activation are distinct, which concurs with attributed functions of the dHP and RSP in spatial memory, as well as of the vHP and LS in emotional responses.

Selective cyclooxygenase-1 inhibition improves collateral vascular reactivity in biliary cirrhotic rats

Directory of Open Access Journals (Sweden)

Ching-Chih Chang

2013-10-01

Conclusion: There was no significant hemodynamic change and renal toxicity after acute administration of COX inhibitor in the FBDL-induced cirrhotic rats. Preincubation of selective COX-1, but not COX-2, inhibitor could enhance collateral vascular response to AVP, indicating that COX-1 plays a major role in the collateral vascular reactivity.

Is Urgent Evoke a Digital Ba?

DEFF Research Database (Denmark)

Wichmand, Mette

2018-01-01

of such a platform, the World Bank’s online game Urgent Evoke, which has been designed with the pur- pose of engaging citizens in developing innovative solutions for sociopolitical problems like poverty. The analysis is based on Nonaka’s concept of Ba, which means “place” and is described as a platform for advancing...

The cortical spatiotemporal correlate of otolith stimulation: Vestibular evoked potentials by body translations.

Science.gov (United States)

Ertl, M; Moser, M; Boegle, R; Conrad, J; Zu Eulenburg, P; Dieterich, M

2017-07-15

The vestibular organ senses linear and rotational acceleration of the head during active and passive motion. These signals are necessary for bipedal locomotion, navigation, the coordination of eye and head movements in 3D space. The temporal dynamics of vestibular processing in cortical structures have hardly been studied in humans, let alone with natural stimulation. The aim was to investigate the cortical vestibular network related to natural otolith stimulation using a hexapod motion platform. We conducted two experiments, 1. to estimate the sources of the vestibular evoked potentials (VestEPs) by means of distributed source localization (n=49), and 2. to reveal modulations of the VestEPs through the underlying acceleration intensity (n=24). For both experiments subjects were accelerated along the main axis (left/right, up/down, fore/aft) while the EEG was recorded. We were able to identify five VestEPs (P1, N1, P2, N2, P3) with latencies between 38 and 461 ms as well as an evoked beta-band response peaking with a latency of 68 ms in all subjects and for all acceleration directions. Source localization gave the cingulate sulcus visual (CSv) area and the opercular-insular region as the main origin of the evoked potentials. No lateralization effects due to handedness could be observed. In the second experiment, area CSv was shown to be integral in the processing of acceleration intensities as sensed by the otolith organs, hinting at its potential role in ego-motion detection. These robust VestEPs could be used to investigate the mechanisms of inter-regional interaction in the natural context of vestibular processing and multisensory integration. Copyright © 2017 Elsevier Inc. All rights reserved.

Stimulus Dependency of Object-Evoked Responses in Human Visual Cortex: An Inverse Problem for Category Specificity

Science.gov (United States)

Graewe, Britta; De Weerd, Peter; Farivar, Reza; Castelo-Branco, Miguel

2012-01-01

Many studies have linked the processing of different object categories to specific event-related potentials (ERPs) such as the face-specific N170. Despite reports showing that object-related ERPs are influenced by visual stimulus features, there is consensus that these components primarily reflect categorical aspects of the stimuli. Here, we re-investigated this idea by systematically measuring the effects of visual feature manipulations on ERP responses elicited by both structure-from-motion (SFM)-defined and luminance-defined object stimuli. SFM objects elicited a novel component at 200–250 ms (N250) over parietal and posterior temporal sites. We found, however, that the N250 amplitude was unaffected by restructuring SFM stimuli into meaningless objects based on identical visual cues. This suggests that this N250 peak was not uniquely linked to categorical aspects of the objects, but is strongly determined by visual stimulus features. We provide strong support for this hypothesis by parametrically manipulating the depth range of both SFM- and luminance-defined object stimuli and showing that the N250 evoked by SFM stimuli as well as the well-known N170 to static faces were sensitive to this manipulation. Importantly, this effect could not be attributed to compromised object categorization in low depth stimuli, confirming a strong impact of visual stimulus features on object-related ERP signals. As ERP components linked with visual categorical object perception are likely determined by multiple stimulus features, this creates an interesting inverse problem when deriving specific perceptual processes from variations in ERP components. PMID:22363479

Imaging the impact of cortical microcirculation on synaptic structure and sensory-evoked hemodynamic responses in vivo.

Directory of Open Access Journals (Sweden)

Shengxiang Zhang

2007-05-01

Full Text Available In vivo two-photon microscopy was used to image in real time dendrites and their spines in a mouse photothrombotic stroke model that reduced somatosensory cortex blood flow in discrete regions of cortical functional maps. This approach allowed us to define relationships between blood flow, cortical structure, and function on scales not previously achieved with macroscopic imaging techniques. Acute ischemic damage to dendrites was triggered within 30 min when blood flow over >0.2 mm(2 of cortical surface was blocked. Rapid damage was not attributed to a subset of clotted or even leaking vessels (extravasation alone. Assessment of stroke borders revealed a remarkably sharp transition between intact and damaged synaptic circuitry that occurred over tens of mum and was defined by a transition between flowing and blocked vessels. Although dendritic spines were normally ~13 microm from small flowing vessels, we show that intact dendritic structure can be maintained (in areas without flowing vessels by blood flow from vessels that are on average 80 microm away. Functional imaging of intrinsic optical signals associated with activity-evoked hemodynamic responses in somatosensory cortex indicated that sensory-induced changes in signal were blocked in areas with damaged dendrites, but were present ~400 microm away from the border of dendritic damage. These results define the range of influence that blood flow can have on local cortical fine structure and function, as well as to demonstrate that peri-infarct tissues can be functional within the first few hours after stroke and well positioned to aid in poststroke recovery.

Vascular pathology: Cause or effect in Alzheimer disease?

Science.gov (United States)

Rius-Pérez, S; Tormos, A M; Pérez, S; Taléns-Visconti, R

2018-03-01

Alzheimer disease (AD) is the main cortical neurodegenerative disease. The incidence of this disease increases with age, causing significant medical, social and economic problems, especially in countries with ageing populations. This review aims to highlight existing evidence of how vascular dysfunction may contribute to cognitive impairment in AD, as well as the therapeutic possibilities that might arise from this evidence. The vascular hypothesis emerged as an alternative to the amyloid cascade hypothesis as an explanation for the pathophysiology of AD. This hypothesis locates blood vessels as the origin for a variety of pathogenic pathways that lead to neuronal damage and dementia. Destruction of the organisation of the blood brain barrier, decreased cerebral blood flow, and the establishment of an inflammatory context would thus be responsible for any subsequent neuronal damage since these factors promote aggregation of β-amyloid peptide in the brain. The link between neurodegeneration and vascular dysfunction pathways has provided new drug targets and therapeutic approaches that will add to the treatments for AD. It is difficult to determine whether the vascular component in AD is the cause or the effect of the disease, but there is no doubt that vascular pathology has an important relationship with AD. Vascular dysfunction is likely to act synergistically with neurodegenerative changes in a cycle that exacerbates the cognitive impairment found in AD. Copyright © 2015 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

The neuropeptide catestatin promotes vascular smooth muscle cell proliferation through the Ca{sup 2+}-calcineurin-NFAT signaling pathway

Energy Technology Data Exchange (ETDEWEB)

Guo, Xiaoxia [Department of Cardiology, People' s Hospital, Peking University, No. 11 South Avenue, Xi Zhi Men Xicheng District, Beijing 100044 (China); Zhou, Chunyan, E-mail: chunyanzhou@bjmu.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University, 38 Xueyuan Road, Haidian District, Beijing 100191 (China); Sun, Ningling, E-mail: nlsun@263.net [Department of Cardiology, People' s Hospital, Peking University, No. 11 South Avenue, Xi Zhi Men Xicheng District, Beijing 100044 (China)

2011-04-22

Highlights: {yields} Catestatin stimulates proliferation of vascular smooth muscle cells in a dose-dependent manner. {yields} Catestatin provokes sustained increase in intracellular Ca{sup 2+}. {yields} Catestatin produces increased activation of calcineurin and promotes NFATc1 translocation into the nucleus. -- Abstract: The Chromogranin A-derived neuropeptide catestatin is an endogenous nicotinic cholinergic antagonist that acts as a pleiotropic hormone. Since catestatin shares several functions with other members derived from the chromogranin/secretogranin protein family and other neuropeptides which exert proliferative effects on vascular smooth muscle cells (VSMCs), we therefore hypothesized that catestatin would regulate VSMC proliferation. The present study demonstrates that catestatin caused a dose-dependent induction of proliferation in rat aortic smooth muscle cells and furthermore evoked a sustained increase in intracellular calcium. This subsequently leaded to enhanced activation of the Ca{sup 2+}/calmodulin-dependent phosphatase, calcineurin and resulted in an activation of the Ca{sup 2+}-dependent transcription factor, nuclear factor of activated T cells (NFAT), initiating transcription of proliferative genes. In addition, cyclosporin A (CsA), a potent inhibitor of calcineurin, abrogated catestatin-mediated effect on VSMCs, indicating that the calcineurin-NFAT signaling is strongly required for catestatin-induced growth of VSMCs. The present study establishes catestatin as a novel proliferative cytokine on vascular smooth muscle cells and this effect is mediated by the Ca{sup 2+}-calcineurin-NFAT signaling pathway.

Multifocal Visual Evoked Potential in Eyes With Temporal Hemianopia From Chiasmal Compression: Correlation With Standard Automated Perimetry and OCT Findings.

Science.gov (United States)

Sousa, Rafael M; Oyamada, Maria K; Cunha, Leonardo P; Monteiro, Mário L R

2017-09-01

To verify whether multifocal visual evoked potential (mfVEP) can differentiate eyes with temporal hemianopia due to chiasmal compression from healthy controls. To assess the relationship between mfVEP, standard automated perimetry (SAP), and Fourier domain-optical coherence tomography (FD-OCT) macular and peripapillary retinal nerve fiber layer (RNFL) thickness measurements. Twenty-seven eyes with permanent temporal visual field (VF) defects from chiasmal compression on SAP and 43 eyes of healthy controls were submitted to mfVEP and FD-OCT scanning. Multifocal visual evoked potential was elicited using a stimulus pattern of 60 sectors and the responses were averaged for the four quadrants and two hemifields. Optical coherence tomography macular measurements were averaged in quadrants and halves, while peripapillary RNFL thickness was averaged in four sectors around the disc. Visual field loss was estimated in four quadrants and each half of the 24-2 strategy test points. Multifocal visual evoked potential measurements in the two groups were compared using generalized estimated equations, and the correlations between mfVEP, VF, and OCT findings were quantified. Multifocal visual evoked potential-measured temporal P1 and N2 amplitudes were significantly smaller in patients than in controls. No significant difference in amplitude was observed for nasal parameters. A significant correlation was found between mfVEP amplitudes and temporal VF loss, and between mfVEP amplitudes and the corresponding OCT-measured macular and RNFL thickness parameters. Multifocal visual evoked potential amplitude parameters were able to differentiate eyes with temporal hemianopia from controls and were significantly correlated with VF and OCT findings, suggesting mfVEP is a useful tool for the detection of visual abnormalities in patients with chiasmal compression.

Creation of a Bioengineered Skin Flap Scaffold with a Perfusable Vascular Pedicle.

Science.gov (United States)

Jank, Bernhard J; Goverman, Jeremy; Guyette, Jacques P; Charest, Jon M; Randolph, Mark; Gaudette, Glenn R; Gershlak, Joshua R; Purschke, Martin; Javorsky, Emilia; Nazarian, Rosalynn M; Leonard, David A; Cetrulo, Curtis L; Austen, William G; Ott, Harald C

2017-07-01

Full-thickness skin loss is a challenging problem due to limited reconstructive options, demanding 75 million surgical procedures annually in the United States. Autologous skin grafting is the gold standard treatment, but results in donor-site morbidity and poor aesthetics. Numerous skin substitutes are available on the market to date, however, none truly functions as full-thickness skin due to lack of a vascular network. The creation of an autologous full-thickness skin analogue with a vascular pedicle would result in a paradigm shift in the management of wounds and in reconstruction of full-thickness skin defects. To create a clinically relevant foundation, we generated an acellular skin flap scaffold (SFS) with a perfusable vascular pedicle of clinically relevant size by perfusion decellularization of porcine fasciocutaneous flaps. We then analyzed the yielded SFS for mechanical properties, biocompatibility, and regenerative potential in vitro and in vivo. Furthermore, we assessed the immunological response using an in vivo model. Finally, we recellularized the vascular compartment of an SFS and reconnected it to a recipient's blood supply to test for perfusability. Perfusion decellularization removed all cellular components with preservation of native extracellular matrix composition and architecture. Biaxial testing revealed preserved mechanical properties. Immunologic response and biocompatibility assessed via implantation and compared with native xenogenic skin and commercially available dermal substitutes revealed rapid neovascularization and complete tissue integration. Composition of infiltrating immune cells showed no evidence of allorejection and resembled the inflammatory phase of wound healing. Implantation into full-thickness skin defects demonstrated good tissue integration and skin regeneration without cicatrization. We have developed a protocol for the generation of an SFS of clinically relevant size, containing a vascular pedicle, which can be

The effectiveness of FES-evoked EMG potentials to assess muscle force and fatigue in individuals with spinal cord injury.

Science.gov (United States)

Ibitoye, Morufu Olusola; Estigoni, Eduardo H; Hamzaid, Nur Azah; Wahab, Ahmad Khairi Abdul; Davis, Glen M

2014-07-14

The evoked electromyographic signal (eEMG) potential is the standard index used to monitor both electrical changes within the motor unit during muscular activity and the electrical patterns during evoked contraction. However, technical and physiological limitations often preclude the acquisition and analysis of the signal especially during functional electrical stimulation (FES)-evoked contractions. Hence, an accurate quantification of the relationship between the eEMG potential and FES-evoked muscle response remains elusive and continues to attract the attention of researchers due to its potential application in the fields of biomechanics, muscle physiology, and rehabilitation science. We conducted a systematic review to examine the effectiveness of eEMG potentials to assess muscle force and fatigue, particularly as a biofeedback descriptor of FES-evoked contractions in individuals with spinal cord injury. At the outset, 2867 citations were identified and, finally, fifty-nine trials met the inclusion criteria. Four hypotheses were proposed and evaluated to inform this review. The results showed that eEMG is effective at quantifying muscle force and fatigue during isometric contraction, but may not be effective during dynamic contractions including cycling and stepping. Positive correlation of up to r = 0.90 (p peak-to-peak amplitude of the eEMG and the decline in the force output during fatiguing isometric contractions has been reported. In the available prediction models, the performance index of the eEMG signal to estimate the generated muscle force ranged from 3.8% to 34% for 18 s to 70 s ahead of the actual muscle force generation. The strength and inherent limitations of the eEMG signal to assess muscle force and fatigue were evident from our findings with implications in clinical management of spinal cord injury (SCI) population.

The Effectiveness of FES-Evoked EMG Potentials to Assess Muscle Force and Fatigue in Individuals with Spinal Cord Injury

Directory of Open Access Journals (Sweden)

Morufu Olusola Ibitoye

2014-07-01

Full Text Available The evoked electromyographic signal (eEMG potential is the standard index used to monitor both electrical changes within the motor unit during muscular activity and the electrical patterns during evoked contraction. However, technical and physiological limitations often preclude the acquisition and analysis of the signal especially during functional electrical stimulation (FES-evoked contractions. Hence, an accurate quantification of the relationship between the eEMG potential and FES-evoked muscle response remains elusive and continues to attract the attention of researchers due to its potential application in the fields of biomechanics, muscle physiology, and rehabilitation science. We conducted a systematic review to examine the effectiveness of eEMG potentials to assess muscle force and fatigue, particularly as a biofeedback descriptor of FES-evoked contractions in individuals with spinal cord injury. At the outset, 2867 citations were identified and, finally, fifty-nine trials met the inclusion criteria. Four hypotheses were proposed and evaluated to inform this review. The results showed that eEMG is effective at quantifying muscle force and fatigue during isometric contraction, but may not be effective during dynamic contractions including cycling and stepping. Positive correlation of up to r = 0.90 (p < 0.05 between the decline in the peak-to-peak amplitude of the eEMG and the decline in the force output during fatiguing isometric contractions has been reported. In the available prediction models, the performance index of the eEMG signal to estimate the generated muscle force ranged from 3.8% to 34% for 18 s to 70 s ahead of the actual muscle force generation. The strength and inherent limitations of the eEMG signal to assess muscle force and fatigue were evident from our findings with implications in clinical management of spinal cord injury (SCI population.