Individual and poly-substance use and condomless sex among HIV-uninfected adults reporting heterosexual sex in a multi-site cohort.

BACKGROUND: We analyzed the association between substance use (SU) and condomless sex (CS) among HIV-negative adults reporting heterosexual sex in the Seek, Test, Treat, and Retain (STTR) consortium. We describe the impact of SU as well as person/partner and context-related factors on CS, identifying combinations of factors that indicate the highest likelihood of CS. METHODS: We analyzed data from four US-based STTR studies to examine the effect of SU on CS using two SU exposures: 1) recent SU (within 3 months) and 2) SU before/during sex. Behavioral data were collected via 1:1 or self-administered computerized interviews. Adjusted individual-study, multivariable relative risk regression was used to examine the relationship between CS and SU. We also examined interactions with type of sex and partner HIV status. Pooled effect estimates were calculated using traditional fixed-effects meta-analysis. We analyzed data for recent SU (n = 6781; 82% men, median age = 33 years) and SU before/during sex (n = 2915; 69% men, median age = 40 years). RESULTS: For both exposure classifications, any SU other than cannabis increased the likelihood of CS relative to non-SU (8-16%, p-values< 0.001). In the recent SU group, however, polysubstance use did not increase the likelihood of CS compared to single-substance use. Cannabis use did not increase the likelihood of CS, regardless of frequency of use. Type of sex was associated with CS; those reporting vaginal and anal sex had a higher likelihood of CS compared to vaginal sex only for both exposure classifications (18-21%, p < 0.001). Recent SU increased likelihood of CS among those reporting vaginal sex only (9-10%, p < 0.001); results were similar for those reporting vaginal and anal sex (5-8%, p < 0.01). SU before/during sex increased the likelihood of CS among those reporting vaginal sex only (20%; p < 0.001) and among those reporting vaginal and anal sex (7%; p = 0.002). Single- and poly-SU before/during sex increased the likelihood of CS for those with exclusively HIV-negative partners (7-8%, p ≤ 0.02), and for those reporting HIV-negative and HIV-status unknown partners (9-13%, p ≤ 0.03). CONCLUSION: Except for cannabis, any SU increased the likelihood of CS. CS was associated with having perceived HIV-negative partners and with having had both anal/vaginal sex.

Computer-Based Substance Use Reporting and Acceptance of HIV Testing Among Emergency Department Patients.

More than 10 years after the Centers for Disease Control and Prevention recommended routine HIV testing for patients in emergency departments (ED) and other clinical settings, as many as three out of four patients may not be offered testing, and those who are offered testing frequently decline. The current study examines how participant characteristics, including demographics and reported substance use, influence the efficacy of a video-based intervention designed to increase HIV testing among ED patients who initially declined tests offered by hospital staff. Data from three separate trials in a high volume New York City ED were merged to determine whether patients (N = 560) were more likely to test post-intervention if: (1) they resembled people who appeared onscreen in terms of gender or race; or (2) they reported problem substance use. Chi Square and logistic regression analyses indicated demographic concordance did not significantly increase likelihood of accepting an HIV test. However, participants who reported problem substance use (n = 231) were significantly more likely to test for HIV in comparison to participants who reported either no problem substance use (n = 190) or no substance use at all (n = 125) (x2 = 6.830, p < 0.05). Specifically, 36.4% of patients who reported problem substance use tested for HIV post-intervention compared to 30.5% of patients who did not report problem substance use and 28.8% of participants who did not report substance use at all. This may be an important finding because substance use, including heavy alcohol or cannabis use, can lead to behaviors that increase HIV risk, such as sex with multiple partners or decreased condom use.

Environmental, health, wellbeing, social and equity effects of urban green space interventions: A meta-narrative evidence synthesis.

BACKGROUND: As populations become increasingly urbanised, the preservation of urban green space (UGS) becomes paramount. UGS is not just dedicated recreational space such as public parks, but other types of informal green space are important, for example, street trees and roof gardens. Despite the potential from cross-sectional evidence, we know little about how to design new, or improve or promote existing UGS for health, wellbeing, social and environmental benefits, or known influencing factors such as physical activity. OBJECTIVES: To perform a meta-narrative review of the evidence regarding the health, wellbeing, social, environmental and equity effects, or known influencing factors of these outcomes, of UGS interventions. DATA SOURCES: Eight electronic databases were searched ((Medline, PsycINFO, Web of Science (Science and Social Science Citation Indices), PADDI (Planning Architecture Design Database Ireland), Zetoc, Scopus, Greenfiles, SIGLE (System for Information on Grey Literature in Europe)), and reference lists of included studies and relevant reviews were hand searched for further relevant studies. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS: Eligibility criteria included: (i) evaluation of an UGS intervention; and (ii) health, wellbeing, social or environmental outcome(s), or known influencing factors of these outcomes, measured. Interventions involving any age group were included. Interventions must have involved: (a) physical change to green space in an urban-context including improvements to existing UGS or development of new UGS, or (b) combination of physical change to UGS supplemented by a specific UGS awareness, marketing or promotion programme to encourage use of UGS. STUDY APPRAISAL AND SYNTHESIS METHODS: Following a meta-narrative approach, evidence was synthesised by main intervention approach, including: (i) park-based; (ii) greenways/trails; (iii) urban greening; (iv) large green built projects for environmental purposes. Outcomes such as economic (e.g. cost effectiveness and cost-benefit analyses), adverse effects and unintended consequences were also extracted. Evidence was synthesised following the RAMESES guidelines and publication standards, the PROGRESS-plus tool was used to explore equity impact, and risk of bias/study quality was assessed. The findings from the evidence review were presented at an expert panel representing various disciplines in a workshop and these discussions framed the findings of the review and provide recommendations that are relevant to policy, practice and research. RESULTS: Of the 6997 studies identified, 38 were included. There was strong evidence to support park-based (7/7 studies) and greenway/trail (3/3 studies) interventions employing a dual-approach (i.e. a physical change to the UGS and promotion/marketing programmes) particularly for park use and physical activity; strong evidence for the greening of vacant lots (4/4 studies) for health, wellbeing (e.g. reduction in stress) and social (e.g. reduction in crime, increased perceptions of safety) outcomes; strong evidence for the provision of urban street trees (3/4 studies) and green built interventions for storm water management (6/7 studies) for environmental outcomes (e.g. increased biodiversity, reduction in illegal dumping). Park-based or greenway/trail interventions that did not employ a dual-approach were largely ineffective (7/12 studies showed no significant intervention effect). Overall, the included studies have inherent biases owing to the largely non-randomized study designs employed. There was too little evidence to draw firm conclusions regarding the impact of UGS interventions on a range of equity indicators. LIMITATIONS; CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: UGS has an important role to play in creating a culture of health and wellbeing. Results from this study provide supportive evidence regarding the use of certain UGS interventions for health, social and environmental benefits. These findings should be interpreted in light of the heterogeneous nature of the evidence base, including diverging methods, target populations, settings and outcomes. We could draw little conclusions regarding the equity impact of UGS interventions. However, the true potential of UGS has not been realised as studies have typically under-evaluated UGS interventions by not taking account of the multifunctional nature of UGS. The findings have implications for policymakers, practitioners and researchers. For example, for policymakers the trajectory of evidence is generally towards a positive association between UGS and health, wellbeing, social and environmental outcomes, but any intervention must ensure that negative consequences of gentrification and unequal access are minimised.

L-dex ratio in detecting breast cancer-related lymphedema: reliability, sensitivity, and specificity.

Advances in bioelectrical impedance analysis (BIA) permit the assessment of lymphedema by directly measuring lymph fluid changes. The objective of the study was to examine the reliability, sensitivity, and specificity of cross-sectional assessment of BIA in detecting lymphedema in a large metropolitan clinical setting. BIA was used to measure lymph fluid changes. Limb volume by sequential circumferential tape measurement was used to validate the presence of lymphedema. Data were collected from 250 women, including healthy female adults, breast cancer survivors with lymphedema, and those at risk for lymphedema. Reliability, sensitivity, specificity and area under the ROC curve were estimated. BIA ratio, as indicated by L-Dex ratio, was highly reliable among healthy women (ICC=0.99; 95% CI = 0.99 - 0.99), survivors at-risk for lymphedema (ICC=0.99; 95% CI = 0.99 - 0.99), and all women (ICC=0.85; 95% CI = 0.81 - 0.87); reliability was acceptable for survivors with lymphedema (ICC=0.69; 95% CI = 0.54 to 0.80). The L-Dex ratio with a diagnostic cutoff of >+7.1 discriminated between at-risk breast cancer survivors and those with lymphedema with 80% sensitivity and 90% specificity (AUC=0.86). BIA ratio was significantly correlated with limb volume by sequential circumferential tape measurement. Cross-sectional assessment of BIA may have a role in clinical practice by adding confidence in detecting lymphedema. It is important to note that using a cutoff of L-Dex ratio >+7.1 still misses 20% of true lymphedema cases, it is important for clinicians to integrate other assessment methods (such as self-report, clinical observation, or perometry) to ensure the accurate detection of lymphedema.

Description of an efficacious behavioral peer-driven intervention to reduce racial/ethnic disparities in AIDS clinical trials.

AIDS clinical trials (ACTs) are critical to the development of new treatments for HIV infection. However, people of color living with HIV/AIDS are involved in ACTs at disproportionally low rates, with African-Americans experiencing the greatest under-representation. In this article, we describe the core elements and key characteristics of a highly efficacious multi-component peer-driven intervention (PDI) designed to increase rates of screening for and enrollment into ACTs among African-American and Latino/Hispanic individuals, by addressing the main complex, multi-level barriers they experience to ACTs. We discuss the process of developing the intervention, the theoretical models guiding its delivery format and content, and provide an overview of the intervention's components. We then use brief case studies to illustrate a number of key issues that may arise during intervention implementation. Finally, we describe lessons learned and provide recommendations for the PDI's uptake in clinical and clinical trials settings.

The effects of symptomatic seroma on lymphedema symptoms following breast cancer treatment.

It has been speculated that symptomatic seroma, or seroma requiring needle aspiration, is one of the risk factors for lymphedema symptoms following breast cancer treatment. These symptoms exert tremendous impact on patients' quality of life and include arm swelling, chest/breast swelling, heaviness, tightness, firmness, pain, numbness, stiffness, or impaired limb mobility. Our aim was to explore if symptomatic seroma affects lymphedema symptoms following breast cancer treatment. Data were collected from 130 patients using a Demographic and Medical Information interview tool, Lymphedema and Breast Cancer Questionnaire, and review of medical record. Arm swelling was verified by Sequential Circumferential Arm Measurements and Bioelectrical Impedance Spectroscopy. Data analysis included descriptive statistics, Chi-squared tests, regression, exploratory factor analysis and exploratory structural equation modeling. Thirty-five patients (27%) developed symptomatic seroma. Locations of seroma included axilla, breast, and upper chest. Significantly, more women with seroma experienced more lymphedema symptoms. A well-fit exploratory structural equation model [X2(79) = 92.15, p = 0.148; CFI = 0.97; TLI = 0.96] revealed a significant unique effect of seroma on lymphedema symptoms of arm swelling, chest/breast swelling, tenderness, and blistering (beta = 0.48, p < 0.01). Patients who developed symptomatic seroma had 7.78 and 10.64 times the odds of developing arm swelling and chest/breast swelling versus those who did not, respectively (p < 0.001). Symptomatic seroma is associated with increased risk of developing lymphedema symptoms following breast cancer treatment. Patients who develop symptomatic seroma should be considered at higher risk for lymphedema symptoms and receive lymphedema risk reduction interventions.

Polyacrylamide gradient gel electrophoresis of lipoprotein subclasses.

High-density (HDL), low-density (LDL), and very-low-density (VLDL) lipoproteins are heterogeneous cholesterol-containing particles that differ in their metabolism, environmental interactions, and association with disease. Several protocols use polyacrylamide gradient gel electrophoresis (GGE) to separate these major lipoproteins into known subclasses. This article provides a brief history of the discovery of lipoprotein heterogeneity and an overview of relevant lipoprotein metabolism, highlighting the importance of the subclasses in the context of their metabolic origins, fates, and clinical implications. Various techniques using polyacrylamide GGE to assess HDL and LDL heterogeneity are described, and how the genetic and environmental determinations of HDL and LDL affect lipoprotein size heterogeneity and the implications for cardiovascular disease are outlined.

Detecting latent taxa: Monte Carlo comparison of taxometric, mixture model, and clustering procedures.

A Monte Carlo evaluation of four procedures for detecting taxonicity was conducted using artificial data sets that were either taxonic or nontaxonic. The data sets were analyzed using two of Meehl's taxometric procedures, MAXCOV and MAMBAC, Ward's method for cluster analysis in concert with the cubic clustering criterion and a latent variable mixture modeling technique. Performance of the taxometric procedures and latent variable mixture modeling were clearly superior to that of cluster analysis in detecting taxonicity. Applied researchers are urged to select from the better procedures and to perform consistency tests.

Knowledge about HIV/AIDS, the perceived risks of infection and sources of information of Asian-Indian adolescents born in the USA.

This study examined the extent and specificity of knowledge about HIV/AIDS, the most used sources of information and the usefulness of these sources among Asian-Indian adolescents who were born in the USA and whose parents emigrated from India. Although 86% knew that having unsafe sex with a person infected with HIV could transmit HIV, 47% did not know that sharing a razor with an HIV-positive person could do so, and a significant proportion believed that donating blood (27%) and taking blood tests (14%) could transmit HIV. Television was the most used source of information, but school programmes on HIV/AIDS were considered the most useful source. The results indicated that to be effective, HIV/AIDS prevention programmes must assess the gap in scientific knowledge and beliefs, and clarify misconceptions, reinforce school programmes to present clear messages about the transmission of HIV/AIDS and utilize television to reach adolescents.

Evaluations of correctional treatment programs in Germany: a review and meta-analysis.

This study presents a review and meta-analyses of research on the recidivism-reducing impact of correctionally based treatment programs in Germany. The data are part of the Correctional Drug Abuse Treatment Effectiveness (CDATE) project meta-analytic database (covering 1968-1996) of evaluation research studies of correctional interventions. Overall, the five studies of educational programs show no practical impact of these programs in reducing recidivism. Four studies of programs to counsel driving-under-the-influence (DUI) offenders fall in an intermediate area (not statistically significant, but promising enough to warrant further research). The eight studies of Social Therapy programs did show, on the average, a statistically significant practical impact in reducing recidivism.

Peer networks, parental attributes, and drug use among Asian-Indian adolescents born in the United States.

This study examined the interrelationships among peer networks, parental attributes, and drug use among Asian-Indian adolescents born in the United States whose parents emigrated from India. The sample consisted of 200 Asian-Indian adolescents, 116 males and 84 females, aged 13 to 18, who were born in the United States and resided in the greater New York metropolitan area. The subjects were interviewed using a semistructured instrument adapted from relevant validated scales and items from other researchers. Adolescent-reported data were analyzed using descriptive and univariable techniques. Of the 200 subjects, 32.5% had tried some form of tobacco, alcohol, or other drug, and 67.5% did not report drug use of any kind. The adolescents stated whether they had ever (at least one time) smoked cigarettes (16.5%), drank beer (18%), drank wine (20.5%), or smoked marijuana (2.5%). The parents' communication of the harmful consequences of drug use and approval of the adolescents' peer networks correlated (p < .05) independently with less drug use by the adolescents. The parents' concern for education was positively correlated (p < .05) with the adolescents' academic performance. The prevalence of drug use among Asian-Indian adolescents is low. Parents' awareness of their children's school performance, peer networks, and concerns related to the consequences of drug use can be used as an effective mechanism to communicate the prevention of drug use among adolescents.

Contributions of glutamate receptors to the maintenance of mustard oil-induced hyperalgesia in spinalized rats.

N-methyl-d-aspartate (NMDA) receptors, which are widely distributed throughout the central nervous system, appear to play a critical role in several types of plasticity and long-term potentiation. In the pain system, increased sensitivity to somatosensory stimuli, known as hyperalgesia and allodynia, can arise from tissue damage or excessive C-fiber nociceptor activation. Previously, NMDA, non-NMDA ionotropic, and metabotropic glutamate receptors have been proposed to contribute to the sustained hyperalgesia following tissue injury or nociceptor activation. Although non-NMDA receptors appear to mediate both hyperalgesia and normal (nonhyperalgesic) responses and behavior, NMDA receptors have been reported to participate only in hyperalgesic responses. In contrast, other studies have implicated NMDA receptors in both hyperalgesic and normal responses. The aim of this study was to critically compare the effects of the glutamate receptor antagonists ketamine and 2-amino-5-phosphonovaleric acid (APV; NMDA receptor antagonists), 6,7-dinitroquinoxaline-2,3-dione (DNQX; non-NMDA ionotropic receptor antagonist), and 2-amino-3-phosphonopropionic acid (AP3; metabotropic receptor antagonist) on intra-articular mustard oil-induced facilitation of flexion withdrawal reflexes in spinalized rats. Our results showed that, as expected from previous studies, ketamine, APV, and DNQX dose-dependently inhibited the flexion withdrawal reflex evoked by C-fiber electrical stimulation of the sciatic nerve. Surprisingly, however, ketamine, APV, and DNQX also inhibited flexion withdrawal reflexes in normal (nonhyperalgesic) rats with similar ED50s. In contrast, AP3 had no effect in either hyperalgesic or normal rats. These results demonstrate that NMDA and non-NMDA ionotropic, but not metabotropic, glutamate receptors contribute without preference to both facilitated and normal flexion withdrawal reflexes evoked by high-intensity electrical stimulation in the spinalized rat. Thus, the apparent preference of NMDA receptors for hyperalgesic states seen in some previous studies on nociception, as well as in other model systems, may have arisen from differences in experimental paradigm, such as the intensity of sensory stimulation or excitability of the spinal cord, coupled with the voltage dependency of the NMDA conductance.

Robustness of taxometric analysis with skewed indicators: II. A Monte Carlo study of the MAXCOV procedure.

A small Monte Carlo study was conducted to determine whether MAXCOV analysis, a taxometric method for testing between discrete ("taxonic") and continuous models of latent variables, is robust when indicators of the latent variable are skewed. Analysis of constructed data sets containing three levels of skew indicated that the MAXCOV procedure is unlikely to yield spurious findings of taxonicity even when skewness is considerable. However, care must be taken to distinguish low base-rate taxonic variables from skewed nontaxonic variables.

Robustness of taxometric analysis with skewed indicators: I. A Monte Carlo study of the MAMBAC procedure.

A small Monte Carlo study was conducted to determine whether Meehl and Yonce's (1994) MAMBAC procedure--a taxometric method for testing between discrete and continuous models of latent variables--is robust when the latent variable and its manifest indicators are skewed. Analysis of constructed data sets containing three levels of skew indicated that the MAMBAC procedure is highly unlikely to yield spurious findings of discreteness ("taxonicity") even when skewness is considerable. MAMBAC appears to be a robust and promising addition to the family of taxometric procedures.

Intrinsic properties of deep dorsal horn neurons in the L6-S1 spinal cord of the intact rat.

1. Stable intracellular recordings were obtained from neurons (n = 62) in the L6-S1 deep dorsal horn of the spinal cord in pentobarbital-sodium-anesthetized, intact rats (n = 26). All neurons responded to natural mechanical stimuli and/or electrical stimulation of peripheral afferents. 2. Intracellular penetrations were maintained for 30 min-2 h. Action potentials occurred spontaneously in most neurons (n = 50) and could be evoked in the remainder (n = 12) by depolarizing current passage. Mean resting membrane potential was -60.9 mV, mean action potential height amplitude was 75.2 mV, mean half-width of the action potentials was 0.33 ms, mean input resistance was 38 M omega, and mean time constant was 9.1 ms. 3. Action potentials were followed by afterpotentials made up of at least three components; a fast afterhyperpolarization (fAHP), a slow afterhyperpolarization (sAHP), and an afterdepolarization (ADP). Most neurons (n = 40) exhibited all three afterpotentials, although some displayed only a fAHP and an ADP (n = 10) or a fAHP and a sAHP (n = 12). The durations and magnitudes of the afterpotentials varied widely among neurons. 4. Steady-state current-voltage relations were investigated in 14 neurons with depolarizing and hyperpolarizing current pulses. Of these 14 neurons, 5 exhibited inward rectification, 3 had outward rectification, and the remaining 6 showed a predominantly linear change of membrane potential to current injection. In addition, several neurons (n = 9) exhibited a postinhibitory rebound that was sometimes (n = 4) accompanied by a "sag" in voltage during the preceding hyperpolarizing current step. 5. Four patterns of spike frequency adaptation occurred during step depolarizing current passage. The firing of most neurons gradually decreased with a simple, approximately exponential time course (n = 21), in some neurons it decreased with both a fast and a slow time course (n = 8), in several it incremented in rate (n = 3), and one neuron showed a complex combination of multiple decrementing and incrementing adaptations. Time constants, magnitude of adaptation, and the slopes of the steady-state current-voltage relation varied widely. 6. Oscillations in membrane potential and firing rate occurred in three neurons. The oscillations arose from endogenous mechanisms in at least one neuron because manipulation of membrane potentials altered the frequency of oscillation; a depolarizing current increased the period of oscillation and eventually produced tonic firing, and a hyperpolarizing current increased the frequency of oscillation and eventually terminated firing. 7. The results demonstrate that neurons in the L6-S1 region of the dorsal horn exhibit a diversity of cellular mechanisms that may significantly modulate normal somatosensory and visceral input.

Functional properties of spinal interneurons activated by muscular free nerve endings and their potential contributions to the clasp-knife reflex.

1. The goal of this study was to characterize the functional properties of spinal interneurons that are excited by muscular free nerve endings and to assess their contributions to the clasp-knife reflex. 2. The patterns of activity of 82 spinal interneurons that were excited by squeezing the Achilles tendon or manipulation of the muscle surfaces, preferential stimuli for muscular free nerve endings, were extracellularly recorded in lamina V-VII of the L5-S1 spinal cord in decerebrated and spinalized cats. 3. Interneurons were uniformly excited by increases in muscular length and force. Responses to muscle stretch exhibited gradual decay during maintained stretch, afterdischarge after stretch release, and adaptation to repeated stretch. Responses to isometric contraction induced by electrical stimulation of motor axons was also prolonged after contraction, but did not decay during maintained contraction. For similar increases in force, stretch evoked greater excitation than contraction, indicating that both stretch and contraction contributed to interneuronal activity. Overall, the time course and magnitude of the interneuronal responses to stretch and contraction paralleled the time course and magnitude of the clasp-knife reflex. 4. Interneurons were powerfully excited by muscular free nerve endings, which mediate the clasp-knife reflex, and by cutaneous receptors. Only occasionally were they excited by primary spindle or Golgi tendon organ afferents, which suggests that activation of muscular free nerve endings mediated the interneuronal responses to stretch and contraction. 5. Simultaneous recordings of interneuronal activity and the clasp-knife reflex revealed a broad correlation between interneuronal activity and clasp-knife inhibition. 6. Because the patterns of activity of free nerve ending-responsive interneurons during stretch and contraction were similar to the clasp-knife reflex, were closely correlated with clasp-knife inhibition during simultaneous interneuronal and reflex recordings, and were powerfully excited by muscular free nerve endings, it is likely that the interneurons described above contributed to the clasp-knife reflex. 7. In contrast, a small number (n = 16) of interneurons were recorded that were only weakly excited by muscular free nerve endings but strongly excited by group I afferents, exhibited less spontaneous and evoked activity, and had significantly different responses to stretch and contraction. These interneurons are less likely to have contributed to the clasp-knife reflex.

Respiratory-modulated and phrenic afferent-driven neurons in the cervical spinal cord (C4-C6) of the fluorocarbon-perfused guinea pig.

The potential contributions of cervical spinal interneurons to the neural control of respiration have been investigated by extracellularly recording the patterns of activity of neurons in the C4-C6 spinal cord during fictive respiration in the fluorocarbon-perfused, adult guinea pig. Two types of neurons were recorded: respiratory-modulated neurons, whose activity was modulated with respiration, and phrenic-driven neurons, which were excited by electrical stimulation of the phrenic nerve. Respiratory-modulated neurons (n = 20) could be divided into inspiratory, expiratory, and phase-spanning neurons, based on their patterns of activity during fictive respiration. Respiratory-modulated neurons showed varying dependencies on the type of breathing; during spontaneous augmented breaths, one-half exhibited patterns of activity that were significantly different to those seen during normal, fictive respiration, whereas the other half of the respiratory-modulated neurons showed similar patterns of activity during both normal and augmented breaths. Phrenic-driven neurons (n = 22) could be divided into short-latency (7-12 ms), moderate-latency (12-25 ms), and inhibited neurons, but were only occasionally and weakly modulated with respiration. The results suggest that respiratory-modulated C4-C6 spinal neurons may contribute to the neural control of respiration, with different subpopulations specialized for different types of respiratory tasks, and that phrenic-driven neurons may be interposed in sensory or reflex pathways, such as the spinothalamic tract or phrenic-to-phrenic inhibitory reflex.