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1.
J Mol Cell Cardiol ; 168: 83-95, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35489388

RESUMO

Various cardiopulmonary pathologies associated with electronic cigarette (EC) vaping have been reported. This study investigated the differential adverse effects of heating-associated by-products versus the intact components of EC aerosol to the lungs and heart of mice. We further dissected the roles of caspase recruitment domain-containing protein 9 (CARD9)-associated innate immune response and NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome in EC exposure-induced cardiopulmonary injury. C57BL/6 wild type (WT), CARD9-/-, and NLRP3-/- mice were exposed to EC aerosol 3 h/day, 5 days/week for 6 month with or without heating the e-liquid with exposure to ambient air as the control. In WT mice, EC exposure with heating (EwH) significantly increased right ventricle (RV) free wall thickness at systole and diastole. However, EC exposure without heating (EwoH) caused a significant decrease in the wall thickness at systole. RV fractional shortening was also markedly reduced following EwH in WT and NLRP3-/- mice. Further, EwH activated NF-κB and p38 MAPK inflammatory signaling in the lungs, but not in the RV, in a CARD9- and NLRP3-dependent manner. Levels of circulatory inflammatory mediators were also elevated following EwH, indicating systemic inflammation. Moreover, EwoH activated TGF-ß1/SMAD2/3/α-SMA fibrosis signaling in the lungs but not the RV of WT mice. In conclusion, EC aerosol exposure following EwH or EwoH induced differential cardiopulmonary remodeling and CARD9 innate immune response and NLRP3 inflammasome contributed to the adverse effects.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Inflamassomos , Animais , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Calefação , Inflamassomos/metabolismo , Pulmão/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo
2.
Pain Physician ; 25(1): 29-34, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35051141

RESUMO

BACKGROUND: Interventions for chronic discogenic spine pain are currently insufficient in lowering individual patient suffering and global disease burden. A 2016 study of platelet rich plasma (PRP) for chronic discogenic pain previously demonstrated clinically significant response among active group patients compared with controls. OBJECTIVES: To replicate the previous research to move this intervention forward as a viable option for patient care. STUDY DESIGN: A double-blind, randomized, placebo-controlled study. SETTING: Multicenter private practices. METHODS: Twenty-six (12 men, 14 women) human patients, ages 25 to 71 with a diagnosis of chronic lumbar discogenic pain, were randomly assigned to active (PRP) or control (saline) groups in a ratio of 2 active to 1 control. Baseline and follow-up Oswestry Disability Index and Numeric Pain Rating Scale questionnaires were obtained to track patient outcomes at 8 weeks postoperatively. RESULTS: Within group assessment showed clinically significant improvement in 17% of PRP patients and clinically significant decline in 5% (1 patient) of the active group. Clinically significant improvement was seen in 13% of placebo group patients and no placebo patients had clinically significant decline secondary to the procedure. LIMITATIONS: Possible explanations may include a range of factors including differences in patient demographics, outcome-measure sensitivity, or misalignment of statistical analyses. CONCLUSIONS: These findings are markedly different than the highly promising results of the 2016 PRP study. This study posits necessary caution for researchers who wish to administer PRP for therapeutic benefit and may ultimately point to necessary redirection of interventional research for discogenic pain populations.


Assuntos
Dor Lombar , Plasma Rico em Plaquetas , Adulto , Idoso , Método Duplo-Cego , Feminino , Humanos , Dor Lombar/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento
3.
Hypertens Res ; 43(12): 1375-1384, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32647279

RESUMO

Macrophage- and monocyte-derived cytokines are elevated in the myocardium of pressure-overloaded hearts, where they play critical roles in pathological remodeling. Caspase recruitment domain family member 9 (CARD9) regulates macrophage cytokine secretion, but its role in a transverse aortic constriction (TAC) model of pressure overload has not been evaluated. To investigate whether CARD9 may serve as a valuable therapeutic target, wild-type (WT) and CARD9-knockout mice were subjected to 3 months of TAC, and then cardiac function, hypertrophy, and fibrosis were analyzed. The expression of protein markers of myocardial autophagy and nuclear factor kappa B signaling was also investigated. At 1 month after TAC, cardiomyocyte contractile dynamics were measured in a separate cohort to further assess contractility and diastolic function. In WT but not CARD9-/- mice, TAC resulted in severe cardiomyocyte contractile dysfunction at 1 month and functional decrements in fractional shortening at 3 months in vivo. Furthermore, CARD9-/- mice did not develop cardiac fibrosis or hypertrophy. CARD9-/- mice also had decreased protein expression of inhibitor of κB kinase-α/ß, decreased phosphorylation of p65, and increased expression of protein markers of autophagy. These findings suggest that CARD9 plays a role in pathological remodeling and cardiac dysfunction in mouse hearts subjected to TAC and should be investigated further.


Assuntos
Proteínas Adaptadoras de Sinalização CARD/metabolismo , Cardiomegalia/metabolismo , Hipertensão/metabolismo , Animais , Autofagia , Feminino , Fibrose , Hipertensão/patologia , Quinase I-kappa B/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Miocárdio/patologia , Miócitos Cardíacos/fisiologia , eIF-2 Quinase/metabolismo
4.
Int J Artif Organs ; 42(1): 49-54, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30223700

RESUMO

BACKGROUND:: The prognosis of hematologic malignancies has improved over the past three decades. However, the prognosis in hematologic malignancies with severe acute respiratory distress syndrome has remained poor. Initial reports regarding the utility of extracorporeal membrane oxygenation in hematologic malignancies have been controversial, with limited evaluations of acute leukemia patients supported by extracorporeal membrane oxygenation. METHODS:: We conducted a retrospective review of patients with acute leukemia who developed acute respiratory distress syndrome requiring veno-venous extracorporeal membrane oxygenation support at our facility from July 2015 through August 2017. RESULTS:: Four cases of acute myelogenous leukemia with respiratory failure and acute respiratory distress syndrome treated with veno-venous extracorporeal membrane oxygenation while undergoing induction chemotherapy were identified. All patients completed induction therapy with addition of extracorporeal membrane oxygenation support, with two patients dying secondary to their acute leukemia and the other two surviving to allogeneic hematopoietic stem cell transplant. Overall, 75% (three of four) survived to decannulation with a 1-year survival rate following extracorporeal membrane oxygenation of 50% (two of four). CONCLUSION:: Currently, the use of extracorporeal membrane oxygenation in patients with hematologic malignancies who develop severe acute respiratory distress syndrome remains controversial. Although extracorporeal membrane oxygenation in post-allogeneic hematopoietic stem cell transplant is associated with poorer outcomes, our data suggest that salvage extracorporeal membrane oxygenation support is a viable option to manage moderate to severe acute respiratory distress syndrome while completing therapeutic chemotherapy and following in the peri-induction phase of acute leukemia.


Assuntos
Oxigenação por Membrana Extracorpórea , Quimioterapia de Indução , Leucemia Mieloide Aguda , Síndrome do Desconforto Respiratório , Adulto , Oxigenação por Membrana Extracorpórea/efeitos adversos , Oxigenação por Membrana Extracorpórea/métodos , Feminino , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Quimioterapia de Indução/efeitos adversos , Quimioterapia de Indução/métodos , Leucemia Mieloide Aguda/complicações , Leucemia Mieloide Aguda/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Síndrome do Desconforto Respiratório/etiologia , Síndrome do Desconforto Respiratório/terapia , Estudos Retrospectivos , Terapia de Salvação/métodos , Análise de Sobrevida , Resultado do Tratamento , Estados Unidos
5.
PLoS One ; 13(6): e0199711, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29940016

RESUMO

Ischemic heart disease remains a leading cause of morbidity and mortality in the United States. Interventional reperfusion induces further damage to the ischemic myocardium through neutrophil infiltration and acute inflammation. As caspase recruitment domain-containing protein 9 (CARD9) plays a critical role in innate immune response and inflammation, we hypothesized that CARD9 knockout would provide protection against ischemia and reperfusion (I/R) injury through attenuation of acute inflammatory responses. C57BL/6 wild-type (WT) and CARD9-/- mice were subjected to 45 min left anterior descending (LAD) coronary artery occlusion followed by 24-h reperfusion. Area at risk (AAR) and infarct size were measured by Evans blue and triphenyltetrazolium chloride (TTC) staining. Frozen heart sections were stained with anti-mouse GR-1 antibody to detect infiltrated neutrophils. Concentrations of cytokines/chemokines TNF-α, IL-6, CXCL-1 and MCP-1 were determined in heart tissue homogenate and serum by ELISA assay. Western immunoblotting analyses were performed to measure the phosphorylation of p38 MAPK. Our results indicate that following I/R, infarct size was significantly smaller in CARD9-/- mice compared to WT. The number of infiltrated neutrophils was significantly lower in CARD9-/- mice compared to WT. Levels of TNF-α, IL-6, CXCL-1 and MCP-1 were significantly reduced in heart tissue and serum from CARD9-/- mice compared to WT. CARD9-/- mice also exhibited significantly lower levels of phosphorylated p38 MAPK. Taken together, our results suggest that CARD9 knockout protects the heart from ischemia/reperfusion (I/R) injury, possibly through reduction of neutrophil infiltration and attenuation of CARD9-associated acute inflammatory signaling.


Assuntos
Proteínas Adaptadoras de Sinalização CARD/deficiência , Sistema de Sinalização das MAP Quinases , Traumatismo por Reperfusão Miocárdica/metabolismo , Miocárdio/metabolismo , Infiltração de Neutrófilos , Neutrófilos/metabolismo , Animais , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Inflamação/genética , Inflamação/metabolismo , Inflamação/patologia , Inflamação/prevenção & controle , Camundongos , Camundongos Knockout , Traumatismo por Reperfusão Miocárdica/genética , Traumatismo por Reperfusão Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miocárdio/patologia , Neutrófilos/patologia , Fosforilação/genética , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
6.
Drug Des Devel Ther ; 10: 3799-3804, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27920495

RESUMO

Systemic inflammation and localized macrophage infiltration have been implicated in cardiovascular pathologies, including coronary artery disease, carotid atherosclerosis, heart failure, obesity-associated heart dysfunction, and cardiac fibrosis. Inflammation induces macrophage infiltration and activation and release of cytokines and chemokines, causing tissue dysfunction by instigating a positive feedback loop that further propagates inflammation. Cytosolic adaptor caspase recruitment domain family, member 9 (CARD9) is a protein expressed primarily by dendritic cells, neutrophils, and macrophages, in which it mediates cytokine secretion. The purpose of this review is to highlight the role of CARD9 as a potential target in inflammation-related cardiovascular pathologies.


Assuntos
Proteínas Adaptadoras de Sinalização CARD/química , Cardiomiopatias/metabolismo , Quimiocinas/metabolismo , Citocinas/metabolismo , Células Dendríticas/metabolismo , Insuficiência Cardíaca/patologia , Macrófagos/química , Miocárdio/patologia , NF-kappa B/química , NF-kappa B/metabolismo , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Proteínas Adaptadoras de Sinalização CARD/fisiologia , Cardiomiopatias/fisiopatologia , Quimiocinas/química , Citocinas/química , Células Dendríticas/química , Insuficiência Cardíaca/metabolismo , Humanos , Miocárdio/química , Transdução de Sinais/efeitos dos fármacos
7.
J Emerg Manag ; 14(4): 245-58, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27575640

RESUMO

Key elements of supply chain theory remain relevant to emergency management (EM) logistics activities. The Supply Chain Operations Reference model can also serve as a useful template for the planning, organizing, and execution of EM logistics. Through a series of case studies (developed through intensive survey of organizations and individuals responsible for EM), the authors identified the extent supply chain theory is being adopted and whether the theory was useful for emergency logistics managers. The authors found several drivers that influence the likelihood of an organization to implement elements of supply chain management: the frequency of events, organizational resources, population density, range of events, and severity of the disaster or emergency.


Assuntos
Planejamento em Desastres , Emergências , Desastres , Humanos
8.
J Mol Cell Cardiol ; 92: 185-95, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26900039

RESUMO

Obesity is associated with chronic inflammation which plays a critical role in the development of cardiovascular dysfunction. Because the adaptor protein caspase recruitment domain-containing protein 9 (CARD9) in macrophages regulates innate immune responses via activation of pro-inflammatory cytokines, we hypothesize that CARD9 mediates the pro-inflammatory signaling associated with obesity en route to myocardial dysfunction. C57BL/6 wild-type (WT) and CARD9(-/-) mice were fed normal diet (ND, 12% fat) or a high fat diet (HFD, 45% fat) for 5months. At the end of 5-month HFD feeding, cardiac function was evaluated using echocardiography. Cardiomyocytes were isolated and contractile properties were measured. Immunofluorescence was performed to detect macrophage infiltration in the heart. Heart tissue homogenates, plasma, and supernatants from isolated macrophages were collected to measure the concentrations of pro-inflammatory cytokines using ELISA kits. Western immunoblotting analyses were performed on heart tissue homogenates and isolated macrophages to explore the underlying signaling mechanism(s). CARD9 knockout alleviated HFD-induced insulin resistance and glucose intolerance, prevented myocardial dysfunction with preserved cardiac fractional shortening and cardiomyocyte contractile properties. CARD9 knockout also significantly decreased the number of infiltrated macrophages in the heart with reduced myocardium-, plasma-, and macrophage-derived cytokines including IL-6, IL-1ß and TNFα. Finally, CARD9 knockout abrogated the increase of p38 MAPK phosphorylation, the decrease of LC3BII/LC3BI ratio and the up-regulation of p62 expression in the heart induced by HFD feeding and restored cardiac autophagy signaling. In conclusion, CARD9 knockout ameliorates myocardial dysfunction associated with HFD-induced obesity, potentially through reduction of macrophage infiltration, suppression of p38 MAPK phosphorylation, and preservation of autophagy in the heart.


Assuntos
Proteínas Adaptadoras de Sinalização CARD/genética , Insuficiência Cardíaca/genética , Inflamação/genética , Obesidade/genética , Animais , Proteínas Adaptadoras de Sinalização CARD/biossíntese , Cardiomiopatias , Dieta Hiperlipídica , Insuficiência Cardíaca/patologia , Humanos , Inflamação/metabolismo , Inflamação/patologia , Resistência à Insulina/genética , Camundongos , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/biossíntese , Proteínas Associadas aos Microtúbulos/genética , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Obesidade/metabolismo , Obesidade/patologia , Transdução de Sinais/genética , Fator de Transcrição TFIIH , Fatores de Transcrição/biossíntese , Proteínas Quinases p38 Ativadas por Mitógeno/biossíntese , Proteínas Quinases p38 Ativadas por Mitógeno/genética
9.
J Emerg Manag ; 12(2): 171-87, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24828913

RESUMO

Much has been written about how emergency management (EM) needs to look to the future regarding issues of resource management (monetary, human, and material). Constraints on budgets are ongoing and the staffing of emergency response activities is often difficult because volunteers have little to no training. The management of material resources has also been a challenge because 1) the categories of material vary by the type of emergency, 2) the necessary quantities of material are often not located near the ultimate point of need, and 3) the transportation assets are rarely available in the form and quantity required to allow timely and effective response. The logistics and resource management functions of EM (what we refer to as EM logistics) have been largely reactive, with little to no pre-event planning for potential demand. We applied the Supply Chain Operational Reference (SCOR) model to EM logistics in an effort to transform it to an integrated and scalable system of physical, information, and financial flows into which are woven the functions of sourcing, making, delivering, and returning, with an overarching planning function that transcends the organizational boundaries of participants. The result is emergency supply chain management, which embraces many more participants who share in a larger quantity of more useful information about the resources that need to be deployed when responding to and recovering from emergency events.


Assuntos
Defesa Civil/organização & administração , Planejamento em Desastres/organização & administração , Desastres/história , História do Século XXI , Humanos , Modelos Organizacionais
10.
Case Rep Med ; 2013: 610726, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23585764

RESUMO

A 24-year-old male Marine with an uncomplicated medical history and a long history of strenuous, daily exercise presented to the emergency department after experiencing anaphylactic shock while running. Symptoms resolved following administration of intramuscular diphenhydramine, ranitidine, intravenous methylprednisolone, and intravenous fluids. On followup in the allergy clinic, a meticulous clinical history was obtained which elucidated a picture consistent with exercise-induced anaphylaxis. He had experienced diffuse pruritus and urticaria while exercising on multiple occasions over the last three years. His symptoms would usually increase as exercise continued. Prior to the first episode, he regularly exercised without symptoms. Exercise-induced anaphylaxis is a rare but potentially life-threatening syndrome that requires a careful clinical history and is a diagnosis of exclusion. Treatment is primarily exercise avoidance. Prophylactic mediations are inconsistently effective but are empirically used. Successful treatment with omalizumab was recently reported in a case of refractory exercise-induced anaphylaxis.

11.
J Neurophysiol ; 96(4): 1755-64, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16855109

RESUMO

The response of a neuron in striate cortex to an optimally oriented stimulus is suppressed by a superimposed orthogonal stimulus. The neural mechanism underlying this cross-orientation suppression (COS) may arise from intracortical or subcortical processes or from both. Recent studies of the temporal frequency and adaptation properties of COS suggest that depression at thalamo-cortical synapses may be the principal mechanism. To examine the possible role of synaptic depression in relation to COS, we measured the recovery time course of COS. We find it too rapid to be explained by synaptic depression. We also studied potential subcortical processes by measuring single cell contrast response functions for a population of LGN neurons. In general, contrast saturation is a consistent property of LGN neurons. Combined with rectifying nonlinearities in the LGN and spike threshold nonlinearities in visual cortex, contrast saturation in the LGN can account for most of the COS that is observed in the visual cortex.


Assuntos
Depressão Sináptica de Longo Prazo/fisiologia , Orientação/fisiologia , Mascaramento Perceptivo/fisiologia , Córtex Visual/fisiologia , Vias Visuais/fisiologia , Animais , Gatos , Potenciais Evocados Visuais/fisiologia , Corpos Geniculados/fisiologia , Sinapses/fisiologia , Fatores de Tempo , Percepção Visual/fisiologia
12.
J Neurophysiol ; 95(4): 2705-12, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16306177

RESUMO

Various properties of external scenes are integrated during the transmission of information along central visual pathways. One basic property concerns the sensitivity to direction of a moving stimulus. This direction selectivity (DS) is a fundamental response characteristic of neurons in the visual cortex. We have conducted a neurophysiological study of cells in the visual cortex to determine how DS is affected by changes in stimulus contrast. Previous work shows that a neuron integration time is increased at low contrasts, causing temporal changes of response properties. This leads to the prediction that DS should change with stimulus contrast. However, the change could be in a counterintuitive direction, i.e., DS could increase with reduced contrast. This possibility is of intrinsic interest but it is also of potential relevance to recent behavioral work in which human subjects exhibit increased DS as contrast is reduced. Our neurophysiological results are consistent with this finding, i.e., the degree of DS of cortical neurons is inversely related to stimulus contrast. Temporal phase differences of inputs to cortical cells may account for this result.


Assuntos
Sensibilidades de Contraste/fisiologia , Neurônios Aferentes/fisiologia , Estimulação Luminosa , Córtex Visual/fisiologia , Animais , Gatos , Modelos Neurológicos , Percepção de Movimento/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Campos Visuais/fisiologia , Vias Visuais/fisiologia
13.
J Neurosci ; 25(39): 9046-58, 2005 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-16192396

RESUMO

The relationship between oxygen levels and neural activity in the brain is fundamental to functional neuroimaging techniques. We have examined this relationship on a fine spatial scale in the lateral geniculate nucleus (LGN) and visual cortex of the cat using a microelectrode sensor that provides simultaneous colocalized measurements of oxygen partial pressure in tissue (tissue oxygen) and multiunit neural activity. In previous work with this sensor, we found that changes in tissue oxygen depend strongly on the location and spatial extent of neural activation. Specifically, focal neural activity near the microelectrode elicited decreases in tissue oxygen, whereas spatially extended activation, outside the field of view of our sensor, yielded mainly increases. In the current study, we report an expanded set of measurements to quantify the spatiotemporal relationship between neural responses and changes in tissue oxygen. For the purpose of data analysis, we develop a quantitative model that assumes that changes in tissue oxygen are composed of two response components (one positive and one negative) with magnitudes determined by neural activity on separate spatial scales. Our measurements from visual cortex and the LGN are consistent with this model and suggest that the positive response spreads over a distance of 1-2 mm, whereas the negative component is confined to a few hundred micrometers. These results are directly relevant to the mechanisms that generate functional brain imaging signals and place limits on their spatial properties.


Assuntos
Corpos Geniculados/fisiologia , Modelos Neurológicos , Oxigênio/metabolismo , Córtex Visual/fisiologia , Animais , Gatos , Corpos Geniculados/metabolismo , Pressão Parcial , Fatores de Tempo , Distribuição Tecidual , Córtex Visual/metabolismo
14.
J Neurophysiol ; 94(2): 1645-50, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15843483

RESUMO

The response of a cell in the primary visual cortex to an optimally oriented grating is suppressed by a superimposed orthogonal grating. This cross-orientation suppression (COS) is exhibited when the orthogonal and optimal stimuli are presented to the same eye (monoptically) or to different eyes (dichoptically). A recent study suggested that monoptic COS arises from subcortical processes; however, the mechanisms underlying dichoptic COS were not addressed. We have compared the temporal frequency tuning and stimulus adaptation properties of monoptic and dichoptic COS. We found that dichoptic COS is best elicited with lower temporal frequencies and is substantially reduced after prolonged adaptation to a mask grating. In contrast, monoptic COS is more pronounced with mask gratings at much higher temporal frequencies and is less prone to stimulus adaptation. These results suggest that monoptic COS is mediated by subcortical mechanisms, whereas intracortical inhibition is the mechanism for dichoptic COS.


Assuntos
Neurônios/fisiologia , Orientação/fisiologia , Visão Binocular/fisiologia , Visão Monocular/fisiologia , Córtex Visual/citologia , Vias Visuais/fisiologia , Potenciais de Ação/fisiologia , Adaptação Fisiológica , Animais , Gatos , Sensibilidades de Contraste/fisiologia , Inibição Neural/fisiologia , Mascaramento Perceptivo/fisiologia , Estimulação Luminosa/métodos
15.
Nat Neurosci ; 7(9): 919-20, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15322552

RESUMO

Functional magnetic resonance imaging is an important tool for measuring brain function noninvasively, but the vascular and metabolic changes on which its measurements are based are not fully understood. Here, we examined the relationship between these changes and neural activity on a fine spatial scale through simultaneous measurements of tissue oxygen and extracellular neural activity in the cat lateral geniculate nucleus. Our findings indicate that activity-dependent increases in cerebral blood flow and oxidative metabolism occur on different spatial scales, and that the ratio between the two depends on the size of the activated neural population.


Assuntos
Circulação Cerebrovascular/fisiologia , Corpos Geniculados/citologia , Neurônios/fisiologia , Vias Visuais/fisiologia , Potenciais de Ação/fisiologia , Animais , Gatos , Corpos Geniculados/irrigação sanguínea , Corpos Geniculados/fisiologia , Imageamento por Ressonância Magnética , Oxigênio/sangue , Estimulação Luminosa/métodos , Percepção de Tamanho/fisiologia
16.
J Neurosci ; 24(14): 3583-91, 2004 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-15071106

RESUMO

In the central visual pathway of binocular animals, the property of directional selectivity (DS) is first exhibited in striate cortex. In this study, we sought to determine the neural circuitry underlying the transformation from non-DS neurons to DS cortical cells. In a well established model, DS receptive fields (RFs) are derived from the sum of two non-DS inputs with 90 degrees (quadrature) spatiotemporal phase differences. We explored possible input sources for this model, which include non-DS simple cells and lateral geniculate nucleus (LGN) neurons, by examination of spatiotemporal RFs of single cells and of pairs of cells. We find that distributions of non-DS simple RFs do not match the temporal predictions of the quadrature model because of a lack of long-latency responses. The long-latency inputs could potentially arise from lagged LGN afferents. However, analysis of cell pairs indicates that DS cells receive cortical input from non-DS simple cells for both short- and long-latency components, with temporal phase differences typically <90 degrees. Furthermore, the distribution of minimum phase differences needed to generate DS cells overlaps that exhibited by non-DS simple cells. Considered together, these results are consistent with a linear model whereby DS simple cells are formed from simple-cell inputs, with temporal phase differences often less than quadrature.


Assuntos
Corpos Geniculados/fisiologia , Modelos Neurológicos , Percepção de Movimento/fisiologia , Neurônios/fisiologia , Córtex Visual/fisiologia , Animais , Gatos , Corpos Geniculados/citologia , Tempo de Reação/fisiologia , Córtex Visual/citologia , Vias Visuais/fisiologia
17.
Neurol Res ; 26(1): 2-8, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14977052

RESUMO

The teaching of mathematics is invariably language-based, but spatial-temporal (ST) reasoning (making a mental image and thinking ahead in space and time) is crucial to the understanding of math. Here we report that Big Seed, a demanding ST video game, based upon the mathematics of knot theory and previously applied to understanding DNA structure and function, can be used to reveal innate ST reasoning. Big Seed studies with middle and elementary school children provide strong evidence that ST reasoning ability is not only innate but far exceeds optimistic expectations based on age, the percentage of children achieving exceptional ST performance in less than 7 h of training, and retention of ability. A third grader has been identified as a genius (functionally defined) in ST performance. Big Seed may be used for training and assessing 'creativity' (functionally defined) and ST reasoning as well as discovering genius.


Assuntos
Criança Superdotada/psicologia , Cognição/fisiologia , Testes de Inteligência/normas , Inteligência/fisiologia , Matemática , Jogos de Vídeo/psicologia , Adolescente , Córtex Cerebral/citologia , Córtex Cerebral/fisiologia , Criança , Avaliação Educacional/métodos , Feminino , Humanos , Masculino , Percepção Espacial/fisiologia , Ensino/métodos , Percepção do Tempo/fisiologia , Jogos de Vídeo/tendências
18.
J Neurophysiol ; 90(1): 204-17, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12611956

RESUMO

The details of oriented visual stimuli are better resolved when they are horizontal or vertical rather than oblique. This "oblique effect" has been confirmed in numerous behavioral studies in humans and to some extent in animals. However, investigations of its neural basis have produced mixed and inconclusive results, presumably due in part to limited sample sizes. We have used a database to analyze a population of 4,418 cells in the cat's striate cortex to determine possible differences as a function of orientation. We find that both the numbers of cells and the widths of orientation tuning vary as a function of preferred orientation. Specifically, more cells prefer horizontal and vertical orientations compared with oblique angles. The largest population of cells is activated by orientations close to horizontal. In addition, orientation tuning widths are most narrow for cells preferring horizontal orientations. These findings are most prominent for simple cells tuned to high spatial frequencies. Complex cells and simple cells tuned to low spatial frequencies do not exhibit these anisotropies. For a subset of simple cells from our population (n = 104), we examined the relative contributions of linear and nonlinear mechanisms in shaping orientation tuning curves. We find that linear contributions alone do not account for the narrower tuning widths at horizontal orientations. By modeling simple cells as linear filters followed by static expansive nonlinearities, our analysis indicates that horizontally tuned cells have a greater nonlinear component than those tuned to other orientations. This suggests that intracortical mechanisms play a major role in shaping the oblique effect.


Assuntos
Neurônios/fisiologia , Orientação , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Potenciais de Ação , Animais , Gatos , Eletrofisiologia , Neurônios/classificação
19.
Science ; 299(5609): 1070-2, 2003 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-12586942

RESUMO

Blood oxygen level-dependent functional magnetic resonance imaging uses alterations in brain hemodynamics to infer changes in neural activity. Are these hemodynamic changes regulated at a spatial scale capable of resolving functional columns within the cerebral cortex? To address this question, we made simultaneous measurements of tissue oxygenation and single-cell neural activity within the visual cortex. Results showed that increases in neuronal spike rate were accompanied by immediate decreases in tissue oxygenation. We used this decrease in tissue oxygenation to predict the orientation selectivity and ocular dominance of neighboring neurons. Our results establish a coupling between neural activity and oxidative metabolism and suggest that high-resolution functional magnetic resonance imaging may be used to localize neural activity at a columnar level.


Assuntos
Neurônios/metabolismo , Consumo de Oxigênio , Córtex Visual/metabolismo , Potenciais de Ação , Animais , Gatos , Circulação Cerebrovascular , Dominância Ocular , Eletrodos Implantados , Hemoglobinas/metabolismo , Cinética , Imageamento por Ressonância Magnética , Microeletrodos , Oxigênio/sangue , Estimulação Luminosa , Córtex Visual/citologia , Córtex Visual/fisiologia
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