What Is Stochastic Resonance? Definitions, Misconceptions, Debates, and Its Relevance to Biology

Stochastic resonance is said to be observed when increases in levels of unpredictable fluctuations—e.g., random noise—cause an increase in a metric of the quality of signal transmission or detection performance, rather than a decrease. This counterintuitive effect relies on system nonlinearities and on some parameter ranges being “suboptimal”. Stochastic resonance has been observed, quantified, and described in a plethora of physical and biological systems, including neurons. Being a topic of widespread multidisciplinary interest, the definition of stochastic resonance has evolved significantly over the last decade or so, leading to a number of debates, misunderstandings, and controversies. Perhaps the most important debate is whether the brain has evolved to utilize random noise in vivo, as part of the “neural code”. Surprisingly, this debate has been for the most part ignored by neuroscientists, despite much indirect evidence of a positive role for noise in the brain. We explore some of the reasons for this and argue why it would be more surprising if the brain did not exploit randomness provided by noise—via stochastic resonance or otherwise—than if it did. We also challenge neuroscientists and biologists, both computational and experimental, to embrace a very broad definition of stochastic resonance in terms of signal-processing “noise benefits”, and to devise experiments aimed at verifying that random variability can play a functional role in the brain, nervous system, or other areas of biology

Seasonal benzathine penicillin G prophylaxis for recurrent streptococcal pharyngitis in children

WOS: 000074763400012PubMed ID: 9695301Background: To assess the efficacy of benzathine penicillin G (BPG) prophylaxis in recurrent streptococcal pharyngitis in children. Methods: One hundred and sixty children, aged 4-11 years, who experienced at least two episodes of group A beta-hemolytic streptococcal (GABHS) pharyngitis during a 4-month observation period between September and December 1995 were randomly divided into two groups. During the following 4-month period between January and April 1996, 80 children received BPG prophylaxis every 3 weeks as a single intramuscular injection of 1.2 million units for a body weight,greater than 27 kg and a half dose for 27 kg or less. Eighty children were accepted as a control group and were not given BPG prophylaxis. Results: The children in the BPG group experienced significantly less GABHS pharyngitis than those in the control group during the second 4-month period (16 vs 244 episodes, respectively, P < 0.001). BPG prophylaxis decreased streptococcal pharyngitis by 92% in the children in the study group, while the frequency of GABHS pharyngitis was unchanged in those in the control group during the second 4-month period compared with the first 4-month period. Conclusions: The data in the present study demonstrated that intramuscular BPG prophylaxis is very effective in preventing GABHS pharyngitis in children. it is recommended that it is used every 3 weeks in at least the fall-winter seasons in children susceptible to frequent GABHS pharyngitis