[Study on the relationship between uncertainty in illness and caregiving burden in family members of patients with chronic wounds].

Objective: To investigate the current status of uncertainty in illness and caregiving burden in family members of patients with chronic wounds, and to analyze the relationship between them. Methods: A total of 180 patients with chronic wounds admitted to the Department of Emergency of our hospital from October 2017 to March 2018, conforming to the study criteria, were selected by adopting the convenience sampling method. Then one family member who took care of the patients for the longest time and conformed to the study criteria were included in this cross-sectional survey. General Information Questionnaire made by the authors was conducted to investigate the demographic data and wounds of patients, and demographic data of family members. Chinese version of Parent Perception of Uncertainty Scale-Family Member (PPUS-FM) and Caregiver Burden Inventory (CBI) were used to investigate the uncertainty in illness and caregiving burden. Data were processed with multiple linear regression analysis and partial correlation analysis. Results: The effective recovery rate of questionnaire was 91.7% (165/180). (1) The ages of patients were (71±17) years. Among them, there were 89 males and 76 females. The course of chronic wounds was 0.5 to 120.0 months. The wounds were mainly primary occurrence (86.1%, 142 patients), and the main type of wound was pressure ulcer (43.6%, 72 patients). Fifty-seven patients (34.5%) had wound infection. The ages of family members were (56±13) years, and 61.8% (102 people) of them were female. Their daily time of taking care of patients was (10±8) h. (2) The total scores of PPUS-FM of family members were 33 to 125 (88±17) points, mainly in medium level, in which the item score of unpredictability dimension was the highest. (3) The total scores of CBI of family members were 7 to 79 (43±14) points, in which the item score of time-dependence burden dimension was the highest. (4) Uncertainty in PPUS-FM could independently influence 10% of the total variation of caregiving burden in family members of patients (t=3.18, P<0.01). (5) The total scores of PPUS-FM of family members were in significantly positive correlation with the total scores of CBI and scores of physical burden, emotional burden, and social burden, respectively (r=0.33, 0.32, 0.25, 0.36, P<0.05 or P<0.01), while there was no obvious correlation between total scores of PPUS-FM of family members and time-dependence burden/developmental burden (r=0.14, 0.16, P>0.05). Conclusion: There is positive correlation between uncertainty in illness and caregiving burden.

Dynamics of spontaneous activity in neocortical slices.

The flow of activity in the cortical microcircuitry is poorly understood. We use calcium imaging to reconstruct, with millisecond and single-cell resolution, the spontaneous activity of populations of neurons in unstimulated slices from mouse visual cortex. We find spontaneous activity correlated among networks of layer 5 pyramidal cells. Synchronous ensembles occupy overlapping territories, often share neurons, and are repeatedly activated. Sets of neurons are also sequentially activated numerous times. Network synchronization and sequential correlations are blocked by glutamatergic antagonists, even though spontaneous firing persists in many "autonomously active" neurons. This autonomous activity is periodic and depends on hyperpolarization-activated cationic (H) and persistent sodium (Na(p)) currents. We conclude that the isolated neocortical microcircuit generates spontaneous activity, mediated by a combination of intrinsic and circuit mechanisms, and that this activity can be temporally precise.

Optical probing of neuronal circuits with calcium indicators.

An experimental difficulty in unraveling circuits in the mammalian nervous system is the identification of postsynaptic targets of a given neuron. Besides ultrastructural reconstructions, simultaneous recordings from pairs of cells in brain slices have been used to identify connected neurons. We describe in this paper a technique using calcium imaging that allows rapid identification of potential postsynaptic targets. This method consists of stimulating one neuron ("trigger") while imaging a population of cells to detect which other neurons ("followers") are activated by the trigger. By using bulk-loading of calcium indicators in slices of mouse visual cortex, we demonstrate that neurons that display somatic calcium transients time-locked to the spikes of a trigger neuron can be monosynaptically connected to it. This technique could be applied to reconstruct and assay circuits in the central nervous system.

The intrinsic dynamics of retinal bipolar cells isolated from tiger salamander.

We studied how intrinsic membrane properties affect the gain and temporal pattern of response in bipolar cells dissociated from retinae of tiger salamanders. Currents specified by a pseudorandom binary sequence, an m-sequence, superimposed on various means, were injected into the cells. From the resultant membrane voltage response for each mean current, impulse responses were estimated. From each impulse response, transfer function, gain, and time constant were calculated. The bipolar cells acted as quasilinear adaptive filters whose gain and response speed are determined by the mean input current. Near resting potential, gain. and time constant were maximum. Dynamics were slow and low-pass, characterized by an approximately exponential impulse response. With depolarization, gains were reduced sharply, responses were much faster, and dynamics became band-pass, as indicated by an undershoot in the impulse response. For any given mean current, the shape of the impulse response did not depend on the amplitude of the m-sequence currents. Thus, bipolar cells behaved in a quasilinear fashion. The adaptive behavior was eliminated by blocking a potassium current, which implicates the role of a voltage-gated potassium conductance. Computer simulations on a model neuron including a delayed-rectifier reconstructed the observed behavior, and provided insight into other, less readily observable, parameters. Thus, bipolar cells, even when isolated, possess mechanisms which regulate, with unsuspected elaborateness, the sensitivities and dynamics of their responsiveness. Implications for adaptation and neuronal processing are discussed.