Role of the Thalamus in Basal Forebrain Regulation of Neural Activity in the Primary Auditory Cortex.

Many studies have implicated the basal forebrain (BF) as a potent regulator of sensory encoding even at the earliest stages of or cortical processing. The source of this regulation involves the well-documented corticopetal cholinergic projections from BF to primary cortical areas. However, the BF also projects to subcortical structures, including the thalamic reticular nucleus (TRN), which has abundant reciprocal connections with sensory thalamus. Here we present naturalistic auditory stimuli to the anesthetized rat while making simultaneous single-unit recordings from the ventral medial geniculate nucleus (MGN) and primary auditory cortex (A1) during electrical stimulation of the BF. Like primary visual cortex, we find that BF stimulation increases the trial-to-trial reliability of A1 neurons, and we relate these results to change in the response properties of MGN neurons. We discuss several lines of evidence that implicate the BF to thalamus pathway in the manifestation of BF-induced changes to cortical sensory processing and support our conclusions with supplementary TRN recordings, as well as studies in awake animals showing a strong relationship between endogenous BF activity and A1 reliability. Our findings suggest that the BF subcortical projections that modulate MGN play an important role in auditory processing.

Laminar firing and membrane dynamics in four visual areas exposed to two objects moving to occlusion.

It is not known how visual cortical neurons react to several moving objects and how their firing to the motion of one object is affected by neurons firing to another moving object. Here we combine imaging of voltage sensitive dye (VSD) signals, reflecting the population membrane potential from ferret visual areas 17, 18, 19, and 21, with laminar recordings of multiunit activity, (MUA), when two bars moved toward each other in the visual field, occluded one another, and continued on in opposite directions. Two zones of peak MUA, mapping the bars' motion, moved toward each other along the area 17/18 border, which in the ferret maps the vertical meridian of the field of view. This was reflected also in the VSD signal, at both the 17/18 border as well as at the 19/21 border with a short delay. After some 125 ms at the area 19/21 border, the VSD signal increased and became elongated in the direction of motion in front of both of the moving representations. This was directly followed by the phase of the signal reversing and travelling back from the 19/21 border toward the 17/18 border, seemingly without respect for retinotopic boundaries, where it arrived at 150 ms after stimulus onset. At this point the VSD signal in front of the moving bar representations along the 17/18 border also increased and became elongated in the direction of object motion; the signal now being the linear sum of what has been observed in response to single moving bars. When the neuronal populations representing the bars were some 600 µm apart on the cortex, the dye signal and laminar MUA decreased strongly, with the MUA scaling to that of a single bar during occlusion. Despite a short rebound of the dye signal and MUA, the MUA after the occlusion was significantly depressed. The interactions between the neuronal populations mapping the bars' position, and the neurons in between these populations were, apart from 19/21 to 17/18 interaction, mainly lateral-horizontal; first excitatory and inducing firing at the site of future occlusion, then inhibitory just prior to occlusion. After occlusion the neurons that had fired already to the first bar showed delayed and prolonged inhibition in response to the second bar. Thus, the interactions that were particular to the occlusion condition in these experiments were local and inhibitory at short cortical range, and delayed and inhibitory after the occlusion when the bars moved further apart.

Discriminative whisking in the head-fixed rat: optoelectronic monitoring during tactile detection and discrimination tasks.

We compared whisking movement patterns during acquisition of tactile detection and object discrimination under conditions in which (a) head movements are excluded and (b) exposure to tactile discriminanda is confined to the large, moveable vibrissae (macrovibrissae). We used optoelectronic instrumentation to track the movements of an individual whisker with high spatio-temporal resolution and a testing paradigm, which allowed us to dissociate performance on an "indicator" response (lever pressing) from the rat's "observing" responses (discriminative whisking). We analyzed the relation between discrimination performance and whisking movement patterns in order to clarify the process by which the indicator response comes under the stimulus control of information acquired by the rat's whisking behavior. Whisking patterns over the course of task acquisition differed with task demands. Acquisition of the Detection task was correlated with modulation of only one whisking movement parameter-total number of whisks emitted, and more whisking was seen on trials in which the discriminandum was absent. Discrimination between a sphere and cube differing in size and texture was correlated with a reduction in whisk duration and protraction amplitude and with a shift towards higher whisking frequencies. Our findings confirm previous reports that acquisition of tactile discriminations involves modulation by the animal of both the amount and the type of whisking. In contrast with a previous report (Brecht et al., 1997), they indicate that rats can solve tactile object detection and discrimination tasks (a) using only the large, motile mystacial vibrissae (macrovibrissae) and (b) without engaging in head movements. We conclude that the functional contribution of the macrovibrissae will vary with the nature of the task and the conditions of testing.

Cortical barrel field ablation and unconditioned whisking kinematics.

The effects of "barrel cortex" ablation upon the biometrics of "exploratory" whisking were examined in three head-fixed rats which had previously sustained unilateral ablation of the left cortical "barrel field" under electrophysiological control. Unconditioned movements of a pair of bilaterally homologous whiskers (C-1, Right, Left) were monitored, optoelectronically, with other whiskers present. Whisking movements on the intact and ablated side were analyzed with respect to kinematics (protraction amplitude and velocity) whisking frequency and phase relationships between whisking movement on the two sides of the face. Histological analysis confirmed complete removal of S-1 "barrel cortex". In normal animals whisking movements have a characteristic rhythm (6-9 Hz), and protractions on the two sides of the face tend to be both synchronous and of very similar amplitudes. In the lesioned animals, whisking frequency was unchanged and whisking movements remained bilaterally synchronous. However, there was a significant difference between the amplitude of Right and Left whisker movements which was evident many months postoperatively. Our results suggest that the deficits in vibrissa-mediated tactile discrimination reported after "barrel" field ablation may reflect an impairment in the animal's ability to modulate whisking parameters on the two sides of the face to meet the functional requirements of a discriminative whisking task. The effects upon whisking amplitude seen after unilateral barrel field ablation are consistent with a model in which the activity of a whisking Central Pattern Generator is modulated by descending inputs to achieve sensorimotor control of whisking movement parameters.

The Incontinence Impact Questionnaire and the Urogenital Distress Inventory: a revisit of their validity in women without a urodynamic diagnosis.

OBJECTIVES: We sought to assess validity of the Incontinence Impact Questionnaire (IIQ) and the Urogenital Distress Inventory (UDI) (long and short forms) in incontinent women previously urodynamically undiagnosed. STUDY DESIGN: Post hoc analysis of responses to the IIQ and UDI questionnaires were obtained from a trial on a urethral device in community-dwelling incontinent women. Internal consistency and validity were evaluated against the 1-hour pad test. RESULTS: Internal consistency (Cronbach's alpha) for the long forms was high for the IIQ and moderately high for the UDI, good for the IIQ-short, but poor for the UDI-short. Correlations with 1h pad test were low and non-significant for both versions. Correlation of the short with the long forms was high. CONCLUSION: In the community-dwelling population, without a urodynamic diagnosis, neither long nor short versions of the questionnaires correlate with the severity of the urinary incontinence as shown by the pad test. The validity of the current questionnaires in women without urodynamic diagnosis is questionable.

Tolterodine versus oxybutynin in the treatment of urge urinary incontinence: a meta-analysis.

OBJECTIVE: To compare tolterodine with oxybutynin in treatment of urge incontinence. STUDY DESIGN: A systematic review, following Cochrane methods, was performed to retrieve results of randomized trials that compared tolterodine with oxybutynin in adults with urge incontinence. Composite point estimates of efficacy (episodes of incontinence per 24-hour period, frequency, and voided volume) and safety (dry mouth, withdrawal, and dose modification) were calculated. RESULTS: Four studies were included. Both drugs similarly decreased the number of micturitions in a 24-hour period. Oxybutynin was marginally superior to tolterodine in decreasing the number of incontinent episodes in a 24-hour period (weighted mean difference, 0.41; 95% confidence interval [CI], 0.04 to 0.77) and increasing the mean voided volume per micturition (8.24 mL; 95% CI, 14.19 to 3.38). Fewer patients had dry mouth (relative risk, 0.54; 95% CI, 0.48 to 0.61) and withdrew from the study because of side effects (relative risk, 0.63; 95% CI, 0.46 to 0.88) with tolterodine. CONCLUSIONS: Oxybutynin and tolterodine share a clinically similar efficacy profile (although oxybutynin is statistically superior), but tolterodine is better tolerated and leads to fewer withdrawals as a result of adverse events.

Urogenital prolapse and atrophy at menopause: a prevalence study.

For 285 subjects referred to a menopause clinic data were prospectively collected on the time elapsed since the onset of menopause (menopausal age), sexual activity, dyspareunia, smoking, chronic cough and constipation. Prolapse and atrophy were sought on examination. FSH assay confirmed menopausal status. We found an anterior wall prolapse in 51% of the subjects, of which 6% were protruding beyond the introitus. Posterior wall prolapse was present in 27% and apical prolapse in 20%; none was protruding beyond the introitus. No trend was noted between prolapse and menopausal age. Atrophy was evident in 34% of the women, and this was related to menopausal age (P<0.001). Forty per cent of the sexually active women admitted to dyspareunia, of which 2/3 were superficial. This correlated with advancing menopausal age (P<0.02). In conclusion, genital prolapse was frequent in the population of postmenopausal women, predominantly cystocele, but the prevalence did not correlate with menopausal age.

Predictive value of clinical evaluation of stress urinary incontinence: a summary of the published literature.

Our objective was to evaluate the symptom and sign of stress incontinence in predicting the presence of urodynamically diagnosed genuine stress incontinence (GSI). The study was a computation of the sensitivity and predictive values from the published literature (1975-1998), evaluating the history and/or physical examination for the diagnosis of GSI, with calculation of efficacy variables. Results show that the isolated symptom of stress incontinence has a positive predictive value (PPV) of 56% for the diagnosis of pure GSI and 79% for GSI with additional abnormalities. The PPV of stress incontinence in association with other symptoms is 77% in detecting GSI (with or without additional abnormalities). A positive cough stress test has a PPV of 55% for detecting pure GSI and 91% for the mixed condition (GSI plus additional diagnosis). When isolated, the symptom or the sign of stress incontinence is a poor predictor of GSI. In combination, the prediction may be more promising.

"Does god have a cochlear implant?".

This article describes psychological and ethical considerations when providing family therapy for parents considering cochlear implantation for their deaf/hard-of-hearing child. Family dynamics, multilevel criteria of informed consent, therapist bias, intervention strategies are illustrated. The clinical vignette of 8-year-old Tommy and his family is largely factual, with enough changes to disguise the participants' identities. I took more creative liberties narrating my daydream to best illustrate the relevant impacts of the pathological and culturally affirmative models.

Point-of-care laboratory testing in critical care.

BACKGROUND: Critical care practitioners are searching for ways to improve the quality and outcomes of care while decreasing cost and length of stay. One technological advance that may facilitate meeting these objectives is bedside or point-of-care laboratory equipment. Evaluation of point-of-care testing for application in each institution requires information about the devices available; knowledge of the advantages and disadvantages of the technologies, the clinical impact, and cost of the process change; and strategies for successful implementation. OBJECTIVES: To review the literature on point-of-care testing and the experience of healthcare professionals who have already successfully implemented this type of testing. METHODS: A total of 81 relevant published articles were reviewed, and 21 critical care units in 8 facilities that use point-of-care testing were visited. Open-ended interviews were conducted with 83 subjects: 56 nurses, 14 laboratory personnel, 9 respiratory therapists, and 4 others. CONCLUSIONS: Point-of-care testing is a technological innovation with the potential for improving patients' care without increasing costs. It most likely will soon become part of the standard of care.

Efficacy of an external urethral device in women with genuine stress urinary incontinence.

The efficacy of a new external anti-incontinence device in patients with a videourodynamic diagnosis of genuine stress incontinence (GSI) in an open longitudinal study is reported. Fourteen women with GSI underwent assessment before and after 3-4 weeks of device use. Assessment consisted of visual analog scores (VAS), quality of life (QOL) questionnaires, urine for culture and a 1 hour pad test. VAS scores showed a significant improvement for the symptom of stress incontinence (P<0.05). QOL scores improved significantly by 38% (P<0.05) and 29% (P<0.01) for the Incontinence Impact Questionnaire and Urogenital Distress Inventory, respectively. The mean pad weight decreased by 47% (P=0.056). Of the 9 women who had a positive pad test (>2 g) without the device, 5 were dry (<2 g) with the device (P<0.05). These preliminary data suggest that this device is effective in women with GSI.

Critical-care-unit bedside design and furnishing: impact on nosocomial infections.

Hospitals in the process of building or renovating intensive-care units (ICUs) often establish multidisciplinary design teams. However, these teams rarely include infection control professionals. Because nosocomial infection is common in the ICU, design features can affect the risk of infection transmission, and outbreaks can occur during construction, this exclusion seems short-sighted. Infection control professionals are familiar with the relevant research, as well as the regulations and guidelines related to ICU design and infection control practices. Not only is their input essential to the design and construction of safe and effective units but their presence on the design team can allow the prospective collection of comparative data to turn the building project into a research project.

A new external urethral occlusive device for female urinary incontinence.

OBJECTIVE: Determine the efficacy of a new external anti-incontinence urethral device. METHODS: A before-after 1 month trial, open longitudinal study of 155 women complaining of urinary incontinence recruited from a referral urogynecology practice and local media advertising was performed. Primary outcomes included assessing the efficacy of the device using visual analogue scales, quality-of-life questionnaires, 1- and 48-hour standardized pad tests, and voiding diary. Secondary outcomes consisted of the evaluation of the adverse effects and the clinical profile of patients willing to use the device after study completion. RESULTS: Ninety-six (62%) of 155 women enrolled completed the study. Scores on the visual analogue scales improved for the symptoms of stress incontinence, urgency, and urge incontinence (P < .001). The score for irritation/discomfort increased (P < .001). Data from diaries showed that 38 (44%, n = 86) patients were dry. Of 454 recorded patient-days, 325 (72%) were dry days. On pad testing, incontinence was cured in 49% (1-hour pad test, n = 59, P < .001) and 44% (48-hour pad test, n = 32, P < .001) of patients. Quality-of-life scores were significantly improved in 48% (n = 96, Incontinence Impact Questionnaire, P < .001) and 32% (n = 96, Urogenital Distress Inventory, P < .001) of patients. There was no increase in bacteriuria. After study completion, 61 (39%) women chose to continue using the device, but this was not predictable from baseline data. CONCLUSION: Use of this device resulted in a significant reduction in incontinence and improvement in quality-of-life issues with minimal adverse events in the majority of women. This new anti-incontinence device could become a useful addition to the armamentarium of nonsurgical options.