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SUMMARY1. Spatial contrast adaptation, produced by prolonged exposure to high contrast grating patterns, has become an important psychophysical method for isolating spatial and orientation selective channels in the human visual system. It has been reasonably argued that this adaptation may be fundamentally dependent upon the activity of neurones in the striate cortex. To test the validity of this hypothesis, and several others, we measured the general adaptation characteristics of 144 striate neurones using a stimulus protocol comparable to the typical psychophysical methods.2. In general, during prolonged high contrast stimulation, the responses of most cells exponentially decayed from a transient peak response to a sustained plateau response; following adaptation, the responses to lower contrasts were depressed relative to the unadapted state but then gradually recovered from the transient depression to a sustained plateau. Such adaptation was a property common to both simple and complex cells (the distributions of the quantitative indices of adaptation were overlapping); there were however small but reliable differences.3. We compared the neurophysiological contrast adaptation with two psychophysical estimates of human contrast adaptation (threshold contrast elevation and apparent contrast reduction) and found that the time courses and the magnitudes were quite similar.4. The effect of contrast adaptation on the spatial frequency tuning was assessed by measuring the contrast response function at several different test spatial frequencies before and after adaptation at the optimum centre frequency. We found that the effect of adaptation decreased as the difference between test and adaptation frequency increased.5. Grating contrast adaptation has been alternatively described as 'constructive gain control' on the one hand and as 'deleterious fatigue' on the other. We tested the effect of contrast adaptation on the contrast response function and found (a) that adaptation shifts the curves vertically downward parallel to the response axis (thus reflecting a decrease in the maximum rate of firing and a deleterious compression of the response range) and (b) that adaptation shifts the curves horizontally to the right parallel to the contrast axis (thus reflecting a true sensitivity shift of the remaining response range for constructive maintenance of high differential sensitivity around the prevailing background level).

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Volunteers engaged in community-based environmental monitoring (CBEM; a form of citizen science) can track changes in species abundance and distribution, measure ecosystem health, and provide data for local, regional and national environmental decision-making. A total of 296 environmental restoration-focused community groups throughout New Zealand responded to an online questionnaire, the objective of which was to investigate the current state of CBEM and contextual factors shaping groups' monitoring activities. Over one-half of groups reported using photo points and 5-Minute Bird Counts (5MBC), with just over one-third (35%; n=218) able to quantify their restoration project objectives through management outcome monitoring (e.g. 5MBC + predator control). Ecosystem monitoring toolkits specifically designed for community users were not widely used (19%; n=157). Groups managing larger areas (e.g. >8 ha), with medium to high partner support and working on Department of Conservation (DOC) or private land were more likely to be conducting their own monitoring. The number of active members in the group and average age of active members did not significantly influence monitoring activity. 'Random Forest' modelling showed that total project area had the strongest independent influence on whether and how groups undertook environmental monitoring. Major challenges for establishing new monitoring programmes were reported as a lack of funding, people (both 45%; n=98), and technical skills (31%). Overall, our results show that significant gains in CBEM could be made by targeting support towards groups managing small areas. The significant positive effect of partner support and constraints imposed by resourcing and technical skills on monitoring activity show that government agencies and science professionals could play a critical role in growing CBEM. Prioritising these collaborative partnerships to design and implement monitoring programmes will maximise the value of monitoring, by meeting groups' and potentially partners' information needs.

Spatial-vision research has been largely concerned with measuring and understanding the consequences of receptive-field properties measured by single-unit recording. However, in order to understand spatial-information processing in the visual system, it is equally essential to know the densities and the distribution patterns of the receptive fields. If the receptive fields are not arrayed properly across the visual field, spatial information will be lost. It has been argued, on the basis of the Whittaker-Shannon sampling theorem, that the receptors of the fovea sample the retinal image at a high enough rate to preserve essentially all the available spatial information. In this paper we show how two-dimensional sampling theory can be used to determine which combinations of receptive-field shapes and sampling patterns would preserve all spatial information from the receptors. This analysis will prove useful for determining, in conjunction with electrophysiological and anatomical evidence, what spatial information is or is not being transmitted by a given stage of the visual pathway. It may also prove useful for developing and testing theories of spatial vision.