Out-of-Pocket Costs of Treatment Among Employer-Insured Women With Invasive Breast Cancer.

This cross-sectional study examines out-of-pocket costs for the treatment of invasive breast cancer in employer-insured women younger than 65 years.

Design of a noninvasive face mask for ocular occlusion in rats and assessment in a visual discrimination paradigm.

The rat visual system is structured such that the large (>90 %) majority of retinal ganglion axons reach the contralateral lateral geniculate nucleus (LGN) and visual cortex (V1). This anatomical design allows for the relatively selective activation of one cerebral hemisphere under monocular viewing conditions. Here, we describe the design of a harness and face mask allowing simple and noninvasive monocular occlusion in rats. The harness is constructed from synthetic fiber (shoelace-type material) and fits around the girth region and neck, allowing for easy adjustments to fit rats of various weights. The face mask consists of soft rubber material that is attached to the harness by Velcro strips. Eyeholes in the mask can be covered by additional Velcro patches to occlude either one or both eyes. Rats readily adapt to wearing the device, allowing behavioral testing under different types of viewing conditions. We show that rats successfully acquire a water-maze-based visual discrimination task under monocular viewing conditions. Following task acquisition, interocular transfer was assessed. Performance with the previously occluded, "untrained" eye was impaired, suggesting that training effects were partially confined to one cerebral hemisphere. The method described herein provides a simple and noninvasive means to restrict visual input for studies of visual processing and learning in various rodent species.

Training-induced plasticity in the visual cortex of adult rats following visual discrimination learning.

Changes in synaptic efficacy, including long-term potentiation (LTP) and long-term depression (LTD), provide mechanisms for experience-induced plasticity and play a key role in learning processes. Some types of learning (e.g., motor learning, fear conditioning) result in LTP and/or LTD-like changes at synapses. Here, rats learned to discriminate two visual stimuli, P+ and P-, indicating the presence and absence, respectively, of a hidden escape platform in a Y-shaped water maze. Following task acquisition, trained rats showed larger amplitude of visually evoked potentials (VEPs) in V1 to both stimuli encountered during training relative to novel stimuli. Training also resulted in a facilitation of LTP induced by theta-burst stimulation (TBS) of thalamic afferents to V1 with no effect on depression induced by low-frequency stimulation (LFS). Visual VEP enhancement and increased LTP both required that visual stimuli carried some significance to the animal, as both effects were absent in control rats exposed to the same visual stimuli in the absence of pairing with platform location. Together, these experiments show that visual experience can result in a stimulus-selective response enhancement and an increase in the synaptic modification range of V1 synapses, providing a novel example of metaplasticity in circuits of the adult cortex.

Assessment of different induction protocols to elicit long-term depression (LTD) in the rat visual cortex in vivo.

Changes in synaptic efficacy, including long-term potentiation (LTP) and long-term depression (LTD), provide mechanisms for experience-induced plasticity of cortical and subcortical circuits. LTP is readily induced under drastically different experimental conditions (e.g., in vitro and in vivo). However, few studies have compared the effectiveness of different induction protocols to elicit synaptic depression, especially under in vivo conditions. Here, we assessed the effectiveness of four different low frequency stimulation (LFS) protocols, applied to the lateral geniculate nucleus, to induce LTD-like changes of local field postsynaptic potentials (fPSPs) recorded on the surface of the primary visual cortex (V1) of urethane-anesthetized rats. Three LFS protocols (900 pulses at 1 Hz; 1800 pulses at 1 Hz, 1800 pulses at 1 Hz, repeated three times), known to induce LTD in neocortical and hippocampal slice preparations, failed to induce synaptic depression. In contrast, strong low frequency burst stimulation (3 pulses/burst at 20 Hz, 900 bursts repeated at 1 Hz) resulted in significant, but transient ( approximately 20 min) depression of fPSPs in V1. This effect was resistant to systemic treatment with MK 801 (0.5 mg/kg) or local, cortical application of either APV (10 mM) or MCPG (10 mM), indicative of non-essential roles of N-methyl-d-aspartate and metabotropic glutamate receptors. A similar depressant effect was also observed under sodium pentobarbital anesthesia. These experiments emphasize the resistance of the in vivo neocortex to express the long-lasting down-regulation of synaptic strength, observations that require integration into current models and theories regarding the functions of LTD as a homeostatic and experience-dependent plasticity mechanism.