Real-time imaging of the medullary circuitry involved in the generation of spontaneous muscle sympathetic nerve activity in awake human subjects

In order to understand the central neural processes involved in blood pressure regulation we recorded muscle sympathetic nerve activity (MSNA) via a tungsten microelectrode in the common peroneal nerve while performing functional Magnetic Resonance Imaging (fMRI) of the brainstem at 3T. Blood Oxygen Level Dependent (BOLD) changes in signal intensity were measured over 4 s every 8 s (200) volumes. Using the MSNA as the input model, we found that increases in sympathetic outflow were associated with robust increases in signal intensity in the region of the rostal ventrolateral medulla (RVLM). Reciprocal decreases in signal intensity occurred in the regions of the nucleus tractus solitarius (NTS) and caudal ventrolateral medulla (CVLM). We show for the first time that this combined approach of recording sympathetic neural activity and fMRI can provide "real-time" imaging of the neural processes responsible for the generation of sympathetic nerve activity in awake human subjects

Esophageal acid stimulation alters insular cortex functional connectivity in gastroesophageal reflux disease

BACKGROUND: The insula plays a significant role in the interoceptive processing of visceral stimuli. We have previously shown that gastroesophageal reflux disease (GERD) patients have increased insular cortex activity during esophageal stimulation, suggesting a sensitized esophago-cortical neuraxis. However, information regarding the functional connectivity (FC) of the insula during visceral stimulation is lacking. The primary aim of this study was to investigate the FC of insular subregions during esophageal acid stimulation. METHODS: Functional imaging data were obtained from 12 GERD patients and 14 healthy subjects during four steady state conditions: (i) presence of transnasal esophageal catheter (pre-infusion); (ii) neutral solution; (iii) acid infusion; (iv) presence of transnasal esophageal catheter following infusions (post-infusion). The insula was parcellated into six regions of interest. FC maps between each insular ROI and interoceptive regions were created. Differences in FC between GERD patients and healthy subjects were determined across the 4 study conditions. KEY RESULTS: All GERD patients experienced heartburn during and after esophageal acidification. Significant differences between GERD patients and healthy subjects were seen in: (i) insula-thalamic FC (neutral solution infusion, acid infusion, post-infusion); (ii) insula-amygdala FC (acid infusion, post-infusion); (iii) insula-hippocampus and insula-cingulate FC (post-infusion). CONCLUSIONS & INFERENCES: Esophageal stimulation in GERD patients revealed significant insular cortex FC differences with regions involved in viscerosensation and interoception. The results of our study provide further evidence that the insula, located at the transition of afferent physiologic information to human feelings, is essential for both visceral homeostasis and the experience of heartburn in GERD patients

Regional cerebral activation accompanies sympathoexcitation in women with polycystic ovary syndrome

Context Polycystic ovary syndrome (PCOS) is associated with increased sympathetic nervous system (SNS) activation but the cerebral pathways involved are unclear. Objective To compare cerebral (blood oxygen level-dependent [BOLD] fMRI), pressor (blood pressure [BP], heart rate [HR]) and muscle sympathetic nerve activity (MSNA) responses to isometric forearm contraction (IFC) in women with PCOS and matched controls. Design Case-control study Setting Referral center Participants 20 subjects with PCOS (age 29.8 ± 4.8yrs, BMI 26.1 ± 4.9kg/ m2) and 20 age/BMI-matched controls (age 29.7 ± 5.0yrs, BMI 26.1 ± 4.8kg/ m2) Main outcome measures BP, HR, catecholamine and MSNA responses to 30% IFC. BOLD signal change modelled for blood pressure response to 30% IFC. Results Whilst HR and BP increased to a similar extent in both groups following IFC, MSNA burst frequency increased by 68% in the PCOS group (n=7) compared to 11.9% in controls (n=7) (p=0.002). Brain activation indexed by the BOLD signal in response to IFC was significantly greater in the PCOS group (n=15) compared to controls (n=15) in the right orbitofrontal cortex (p<0.0001). Adjustment for insulin sensitivity, but not hyperandrogenism, abolished these between-group differences. Conclusions Our study confirms enhanced sympathoexcitation in women with PCOS and demonstrates increased regional brain activation in response to IFC. The right orbitofrontal cortex BOLD signal change in women with PCOS is associated with insulin sensitivity. Further studies are warranted to clarify whether this may offer a novel target for cardiovascular risk reduction

Cortical mapping of the neuronal circuits modulating the muscle tone. Introduction to the electrophysiological treatment of the spastic hand

L'objectiu d'aquest estudi es investigar l'organització cortical junt amb la connectivitat còrtico-subcortical en subjectes sans, com a estudi preliminar. Els mapes corticals s'han fet per TMS navegada, i els punts motors obtinguts s'han exportant per estudi tractogràfic i anàlisi de las seves connexions. El coneixement precís de la localització de l'àrea cortical motora primària i les seves connexions es la base per ser utilitzada en estudis posteriors de la reorganització cortical i sub-cortical en pacients amb infart cerebral. Aquesta reorganització es deguda a la neuroplasticitat i pot ser influenciada per els efectes neuromoduladors de la estimulació cerebral no invasiva.The purpose of this study is to investigate the motor cortex organisation together with the cortico-subcortical connectivity in healthy subjects, as a preliminary study. Cortical maps have been performed by navigated TMS and the motor points have been exported to DTI to study their subcortical connectivity. The precise knowledge of localization of the primary motor cortex area and its connectivity is the base to be used in later studies of cortical and subcortical re-organisation in stroke patients. This re-organisation is due to the neuroplascity and can be influenced by the neuromodulation effects of the non-invasive cerebral stimulation therapy by TMS

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 218, April 1981

This bibliography lists 161 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1981

Changed vibration threshold and loss of nerve movement in patients with repetitive strain injury; the peripheral neuropathology of RSI

Changed vibration threshold and loss of nerve movement in patients with repetitive strain injury; the peripheral neuropathology of RSI Repetitive strain injury (RSI) is a chronic pain condition affecting the upper limbs. It has been associated with tasks that require repetitive and intensive hand activities, particularly when these are carried out in constrained postures. Patients present with significant symptoms, but when examined, lack signs of specific inflammatory conditions or single peripheral nerve disorder. In consequence there have been considerable problems in the diagnosis of RSI and in designing effective treatment. Partial injury to peripheral nerves can produce significant symptoms and allodynic changes in the presence of normal nerve conduction studies. It therefore seemed possible that minor neuropathy might be an important contributor to RSI. To test this, vibration threshold was measured in patients with RSI and in a group of "at risk" office workers. Significantly raised thresholds were found, particularly affecting the median nerve, in both the patients and office workers. Following five minutes of keyboard use the patients showed a further rise in vibration threshold. Patients also showed reduced tolerance to non noxious suprathreshold vibration. These sensory changes are consistent with the changes observed in patients with diagnosed neuropathy. In further studies we imaged the median nerve at the carpal tunnel using MRI and high frequency ultrasound. The dynamics of the median nerve were studied during 30 degrees of wrist flexion and extension. A significant quantitative reduction of nerve movement was seen in patients. A correlation was found between nerve movement measured objectively and a clinical test of median nerve dynamics. How loss of normal nerve dynamics could contribute to the symptoms experienced by these patients is discussed. It is concluded that minor nerve injury forms part of the pathology of RSI and that testing vibration threshold and examining nerve movement could contribute to diagnosis and prove useful in evaluating treatment outcomes

Neuromodulation of spinal autonomic regulation

The central nervous system is largely responsible for receiving sensory information from the environment and determining motor output. Yet, centrally-derived behavior and sensation depends on the optimal maintenance of the cells, tissues, and organs that feed and support these functions. Most of visceral regulation occurs without conscious oversight, making the spinal cord a key site for integration and control. How the spinal cord modulates output to our organs, or sensory information from them, is poorly understood. The overall aim of this dissertation was to better understand spinal processing of both visceral sensory information to and sympathetic output from the spinal cord. I first established and validated a HB9-GFP transgenic mouse model that unambiguously identified sympathetic preganglionic neurons (SPNs), the spinal output neurons for the sympathetic nervous system. Using this model, I investigated the electrophysiological similarities and diversity of SPNs, and compared their active and passive membrane properties to those in other animal models. My results indicate that while many of the same characteristics are shared, SPNs are a heterogeneous group that can be differentiated based on their electrophysiological properties. Since descending monoaminergic pathways have particularly dense projections to sympathetic regions of the spinal cord, I next examined the modulatory role that the monoamines have on spinal sympathetic output. While each neuromodulator tested had a unique signature of action, serotonin and norepinephrine appeared to increase the excitability of individual SPNs, while dopamine had more mixed actions. Since many autonomic reflexes are integrated by the spinal cord, I also questioned whether these reflexes would be similarly modulated. I therefore developed a novel in vitro spinal cord and sympathetic chain preparation, which allowed for the investigation of visceral afferent-mediated reflexes and their neuromodulation by monoamines. This preparation exposed a dichotomy of action, where sympathetic and somatic motor output is generally enhanced by the monoamines, but reflexes mediated by visceral input are depressed. Utilizing the spinal cord and sympathetic chain preparation, I also investigated how the spinal cord modulates visceral sensory information. One of the most powerful means of selectively inhibiting afferent information from reaching the spinal cord is presynaptic inhibition. I hypothesized that both spinal visceral afferents and descending monoaminergic systems would depress transmission of visceral afferents to the spinal cord. My results demonstrated that activity in spinal visceral afferents can lead to spinally generated presynaptic inhibition, and that in addition to depressing synaptic transmission to the spinal cord, the monoamines also depress the intrinsic circuitry that generates this activity-dependent presynaptic inhibition. Taken together, my results indicate that descending monoaminergic pathways act to limit the amount of visceral sensory information reaching the central nervous system and increase sympathetic output, resulting in an uncoupling of output from visceral sensory input and transitioning to a feed-forward, sympathetically dominant control strategy. This combination offers complex modulatory strategies for descending systems.PhDCommittee Chair: Hochman, Shawn; Committee Member: Nichols, Richard T; Committee Member: Schramm, Lawrence; Committee Member: Shinohara, Minoru; Committee Member: Tansey, Keit

Neuromarketing empirical approaches and food choice: A systematic review

Consumers' food choices are often driven by reasons of which consumers are not fully aware. Decision-making about food is influenced by a complex set of emotions, feelings, attitudes, and values that are impossible to assess simply by asking consumers their opinions. Indeed, traditional techniques, such as self-reports or interviews, mainly allow the measurement of conscious and rational reactions to a product or advertising. Recently, there has been a rapidly growing interest in the multidisciplinary field of “neuromarketing,” which takes advantage of neuroscientific techniques to study consumer behavior. This discipline applies neuroscientific methods and tools that allow the measurement of consumers' emotional and spontaneous reactions in a more objective and observable way. The aim of this paper is (a) to describe neuromarketing's underlying assumptions, techniques, and the advantages of this perspective, examining the scientific literature on the use of neuromarketing in food studies; and (b) to suggest best practices to apply this novel approach in the food marketing domain, with a specific focus on non-invasive methods. Finally, although the perception of nutritional elements has already been explored, the health content of labels, the presence of additives, and the evaluation of the information conveyed by food packaging remain other possible elements of interest in future food neuromarketing research

Topics in Neuromodulation Treatment

"Topics in Neuromodulation Treatment" is a book that invites to the reader to make an update in this important and well-defined area involved in the Neuroscience world. The book pays attention in some aspects of the electrical therapy and also in the drug delivery management of several neurological illnesses including the classic ones like epilepsy, Parkinson's disease, pain, and other indications more recently incorporated to this important tool like bladder incontinency, heart ischemia and stroke. The manuscript is dedicated not only to the expert, but also to the scientist that begins in this amazing field. The authors are physicians of different specialties and they guarantee the clinical expertise to provide to the reader the best guide to treat the patient