We investigated the hypothesis that task performance can rapidly and adaptively reshape cortical receptive field properties in accord with specific task demands and salient sensory cues. We recorded neuronal responses in the primary auditory cortex of behaving ferrets that were trained to detect a target tone of any frequency. Cortical plasticity was quantified by measuring focal changes in each cell's spectrotemporal response field (STRF) in a series of passive and active behavioral conditions. STRF measurements were made simultaneously with task performance, providing multiple snapshots of the dynamic STRF during ongoing behavior. Attending to a specific target frequency during the detection task consistently induced localized facilitative changes in STRF shape, which were swift in onset. Such modulatory changes may enhance overall cortical responsiveness to the target tone and increase the likelihood of 'capturing' the attended target during the detection task. Some receptive field changes persisted for hours after the task was over and hence may contribute to long-term sensory memory.
To understand the neural representation of broadband, dynamic sounds in primary auditory cortex (AI), we characterize responses using the spectro-temporal response field (STRF). The STRF describes, predicts, and fully characterizes the linear dynamics of neurons in response to sounds with rich spectro-temporal envelopes. It is computed from the responses to elementary "ripples," a family of sounds with drifting sinusoidal spectral envelopes. The collection of responses to all elementary ripples is the spectro-temporal transfer function. The complex spectro-temporal envelope of any broadband, dynamic sound can expressed as the linear sum of individual ripples. Previous experiments using ripples with downward drifting spectra suggested that the transfer function is separable, i.e., it is reducible into a product of purely temporal and purely spectral functions. Here we measure the responses to upward and downward drifting ripples, assuming reparability within each direction, to determine if the total bidirectional transfer function is fully separable. In general, the combined transfer function for two directions is not symmetric, and hence units in AI are not, in general, fully separable. Consequently, many AI units have complex response properties such as sensitivity to direction of motion, though most inseparable units are not strongly directionally selective. We show that for most neurons, the lack of full separability stems from differences between the upward and downward spectral cross-sections but not from the temporal cross-sections; this places strong constraints on the neural inputs of these AI units.
Background: Medical mistrust, a result of systemic racism, is prevalent among Black Americans and may play a role in COVID-19 inequities. In a convenience sample of HIV-positive Black Americans, we examined associations of COVID-19-related medical mistrust with COVID-19 vaccine and COVID-19 treatment hesitancy and negative impacts of COVID-19 on antiretroviral therapy (ART) adherence. Methods: Participants were 101 HIV-positive Black Americans (age: M = 50.3 years; SD = 11.5; 86% cisgender men; 77% sexual minority) enrolled in a randomized controlled trial of a community-based ART adherence intervention in Los Angeles County, CA. From May to July 2020, participants completed telephone interviews on negative COVID-19 impacts, general COVID-19 mistrust (eg, about the government withholding information), COVID-19 vaccine and treatment hesitancy, and trust in COVID-19 information sources. Adherence was monitored electronically with the Medication Event Monitoring System. Results: Nearly all participants (97%) endorsed at least one general COVID-19 mistrust belief, and more than half endorsed at least one COVID-19 vaccine or treatment hesitancy belief. Social service and health care providers were the most trusted sources. Greater COVID-19 mistrust was related to greater vaccine and treatment hesitancy [b (SE) = 0.85 (0.14), P < 0.0001 and b (SE) = 0.88 (0.14), P < 0.0001, respectively]. Participants experiencing more negative COVID-19 impacts showed lower ART adherence, assessed among a subset of 49 participants [b (SE) = −5.19 (2.08), P = 0.02]. Discussion: To prevent widening health inequities, health care providers should engage with communities to tailor strategies to overcome mistrust and deliver evidence-based information, to encourage COVID-19 vaccine and treatment uptake.
Deficits in the quality of care provided to children appear to be similar in magnitude to those previously reported for adults. Strategies to reduce these apparent deficits are needed.
Context Readmission rates are used as an indicator of the quality of care that patients receive during a hospital admission and after discharge. Objective To determine the prevalence of pediatric readmissions and the magnitude of variation in pediatric readmission rates across hospitals. Design, Setting, Patients We analyzed 568,845 admissions at 72 children's hospitals between 7/1/2009 and 6/30/2010 in the National Association of Children's Hospitals and Related Institutions Case Mix dataset. We estimated hierarchical regression models for 30-day readmission rates by hospital, accounting for age and chronic condition indicators. Hospitals with adjusted readmission rates that were one standard deviation above and below the mean were defined as having “high” and “low” rates, respectively. Main Outcome Measure Thirty-day unplanned readmissions following admission for any diagnosis and for the 10 admission diagnoses with the highest readmission prevalence. Planned readmissions were identified with ICD-9-CM procedure codes. Results The 30-day unadjusted readmission rate for all hospitalized children was 6.5% (n=36,734). Adjusted rates were 28.6% greater in hospitals with high vs. low readmission rates [7.2% (95% CI 7.1–7.2%) vs. 5.6% (95% CI 5.6-5.6%)]. For the 10 admissions diagnoses with the highest readmission prevalence, the adjusted rates were 17.0% to 66.0% greater in hospitals with high vs. low readmission rates. For example, sickle cell rates were 20.1% (95% CI 20.0–20.3%) vs. 12.7% (95% CI 12.6–12.8%) in high vs. low hospitals, respectively. Conclusions Among patients admitted to acute care pediatric hospitals, the rate of unplanned readmissions at 30 days was 6.5%. There was wide variability in readmission rates across conditions and hospitals.
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