The influence of temporal and spatial context during haptic roughness perception was investigated in two experiments. Subjects examined embossed dot patterns of varying average dot distance. A two-alternative forced-choice procedure was used to measure discrimination thresholds and biases. In Experiment 1, subjects had to discriminate between two stimuli that were presented simultaneously to adjacent fingers, after adaptation of one of these fingers. The results showed that adaptation to a rough surface decreased the perceived roughness of a surface subsequently scanned with the adapted finger, whereas adaptation to a smooth surface increased the perceived roughness (i.e. contrast after effect). In Experiment 2, subjects discriminated between subsequent test stimuli, while the adjacent finger was stimulated simultaneously. The results showed that perceived roughness of the test stimulus shifted towards the roughness of the adjacent stimulus (i.e. assimilation effect). These contextual effects are explained by structures of cortical receptive fields. Analogies with comparable effects in the visual system are discussed.

BACKGROUND/AIM A cost-effectiveness analyses of immunomodulatory treatments for relapsing-remitting multiple sclerosis (RRMS) in developed countries have shown that any benefit from these drugs is achieved at very high cost. The aim of our study was to compare the cost-effectiveness of five treatment strategies in patients diagnosed with RRMS (symptom management alone and in combination with subcutaneous glatiramer acetate, intramuscular interferon beta-1a, subcutaneous interferon beta-1a, or intramuscular interferon [beta-1b) in a Balkan country in socio-economic transition. METHODS The Markov model was developed based on the literature about effectiveness and on local Serbian cost calculations. The duration of a cycle in the model was set to a month. The baseline time horizon was 480 months (40 years). The societal perspective was used for costs and outcomes, and they were discounted for 3% annually. Monte Carlo micro simulation with 1000 virtual patients was done. RESULTS Significant gain with immunomodulatory therapy was achieved only in relapse-free years, while the time spent in health states EDSS 0.0-5.5 was longer with symptomatic therapy only, and gains in life years and QALYs were only marginal. One QALY gained costs more than a billion of Serbian dinars (more than 20 million US dollars), making each of the four immunomodulatory therapies cost-ineffective. CONCLUSION Our study suggests that immunomodulatory therapy of RRMS in a Balkan country in socioeconomic transition is not cost-effective, regardless of the type of the therapy. Moderate gain in relapse-free years does not translate to gain in QALYs, probably due to adverse effects of immunomodulatory therapy.