Brief localised monocular deprivation in adults alters binocular rivalry predominance retinotopically and reduces spatial inhibition

Short-term deprivation (2.5 h) of an eye has been shown to boost its relative ocular dominance in young adults. Here, we show that a much shorter deprivation period (3–6 min) produces a similar paradoxical boost that is retinotopic and reduces spatial inhibition on neighbouring, non-deprived areas. Partial deprivation was conducted in the left hemifield, central vision or in an annular region, later assessed with a binocular rivalry tracking procedure. Post-deprivation, dominance of the deprived eye increased when rivalling images were within the deprived retinotopic region, but not within neighbouring, non-deprived areas where dominance was dependent on the correspondence between the orientation content of the stimuli presented in the deprived and that of the stimuli presented in non-deprived areas. Together, these results accord with other deprivation studies showing V1 activity changes and reduced GABAergic inhibition.

Visual plasticity and exercise revisited: no evidence for a “cycling lane”

Experiments using enriched environments have shown that physical exercise modulates visual plasticity in rodents. A recent study (Lunghi & Sale, 2015, doi: 10.1016/j.cub.2015.10.026) investigated whether exercise also affects visual plasticity in adult humans. The plastic effect they measured was the shift in ocular dominance caused by 2 hours of monocular deprivation (e.g. by an eye patch). They used a binocular rivalry task to measure this shift. They found that the magnitude of the shift was increased by exercise during the deprivation period. This effect of exercise was later disputed by a study that used a different behavioural task (Zhouet al., 2017, doi: 10.1155/2017/4780876). Our goal was to determine whether the difference in task was responsible for that study’s failure to find an exercise effect. We set out to replicate Lunghi & Sale (2015). We measured ocular dominance with a rivalry task before and after 2 hours of deprivation. We measured data from two conditions in 30 subjects. On two separate days they either performed exercise or rested during the deprivation period. Contrary to the previous study, we find no significant effect of exercise. We hypothesise that exercise may affect rivalry dynamics in a way that interacts with the measurement of the deprivation effect.

A Prototypical First-Generation Electronic Cigarette Does Not Reduce Reports of Tobacco Urges or Withdrawal Symptoms among Cigarette Smokers

It is unknown whether first-generation electronic cigarettes reduce smoking urges and withdrawal symptoms following a 24 h deprivation period. This study tested whether a first-generation electronic cigarette reduces smoking urges and withdrawal symptoms in cigarette smokers. Following 24 h of tobacco deprivation, using a within-subjects design, eight nontreatment seeking tobacco cigarette smokers (3 females) administered 10 puffs from a conventional cigarette or a first-generation electronic cigarette containing liquid with 0, 8 or 16 mg/ml nicotine. Conventional cigarettes ameliorated smoking urges and electronic cigarettes did not, regardless of nicotine concentration. First-generation electronic cigarettes may not effectively substitute for conventional cigarettes in reducing smoking urges, regardless of nicotine concentration.

Effect of oxygen deprivation on treatment processes in a full-scale drinking water biofilter

Dissolved oxygen is critical for proper operation of waterworks that utilize anaerobic groundwater and rely on biofilters to remove iron, manganese and ammonium. In these biofilters, planned or inadvertent oxygen deprivation may occur for a variety of reasons. The water quality effects of oxygen deprivation on the function of drinking water biofilters, however, have not previously been reported. In this study, a 5-day oxygen deprivation period in full-scale biofilters was found to affect iron, manganese and ammonium concentrations differently. During the oxygen deprivation period, iron continued to be removed, although a greater depth of filter media was required to carry out the removal. Manganese oxide in filter media was mobilized, causing manganese water concentrations to increase well above raw water levels. The ammonium in the raw water passed through the biofilters unchanged, indicating the dependence of nitrification microorganisms on oxygen as their sole electron acceptor. Stringent national drinking water criteria were exceeded during the deprivation period but were once again met within hours after oxygenation was recommenced. Manganese and nitrite recovery to pre-deprivation concentrations, however, required days. The results illustrate the interdependence of treatment parameters and provide valuable practical information to waterworks that experience or plan oxygen stoppage.