Stereotactic coordinates of canine subcortical ganglia

From a study of serial frontal sections of the brains of 30 dogs weighing from 1.6 to 36.0 kg and having a length of cranium (brain case) from 60 to 130 mm, we have established the anatomical relationship of the Sylvian fossa to the basal ganglia. A new method has been proposed for precise determination of the stereotactic coordinates of the subcortical nuclei of the forebrain in the living dog. The reference point serving as zero for the stereotactic planes is taken as the Sylvian fossa.Translated from Neirofiziologiya, Vol. 1, No. 3, pp. 331–335, November–December, 1969.     

Spontaneous electrical activity of the claustrum

The dynamics of spontaneous electrical activity of the rostral, dorsal, ventral, and caudal parts of the claustrum were studied in chronic experiments on 12 dogs with implanted electrodes during extinction of orienting reactions and during biologically meaningful changes in the animals' functional state. In the animal at rest, electrical activity of the claustrum was similar to that of subcortical structures, but in a state of attention, its activity began to resemble that of the electrocorticogram, in agreement with the view that this nucleus occupies an intermediate position between cortical and subcortical structures. Enhancement of fast activity in the claustrum with the appearance of orienting reactions was expressed more intensively, and during extinction it was preserved for a longer time, in the dorsal and ventral parts of the claustrum than in the rostral and caudal parts, evidence of structural heterogeneity of the nucleus. Under conditions of increased food excitability the amplitude and frequency of the fast waves recorded from the rostral and caudal parts of the claustrum were selectively increased, whereas during reflexes to a rejected stimulus (acids) and in defensive reflexes they were increased in recordings from the dorsal and ventral parts, on which basis the existence of specialized efferent zones participating in biologically different types of activity can be postulated. Enhancement of fast activity in the claustrum during reflexes to food and acid differed in its genesis: The switch from the first to the second took place through a phase of suppression of the first. Differentiation of a food-conditioned stimulus was accompanied by the development of active inhibition in the "food zones" of the claustrum and by enhancement of activity in the "zones of orienting reactions."A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 12, No. 2, pp. 155–164, March–April, 1980.     

Estimating the global distribution of field size using crowdsourcing

There is an increasing evidence that smallholder farms contribute substantially to food production globally, yet spatially explicit data on agricultural field sizes are currently lacking. Automated field size delineation using remote sensing or the estimation of average farm size at subnational level using census data are two approaches that have been used. However, both have limitations, for example, automatic field size delineation using remote sensing has not yet been implemented at a global scale while the spatial resolution is very coarse when using census data. This paper demonstrates a unique approach to quantifying and mapping agricultural field size globally using crowdsourcing. A campaign was run in June 2017, where participants were asked to visually interpret very high resolution satellite imagery from Google Maps and Bing using the Geo‐Wiki application. During the campaign, participants collected field size data for 130 K unique locations around the globe. Using this sample, we have produced the most accurate global field size map to date and estimated the percentage of different field sizes, ranging from very small to very large, in agricultural areas at global, continental, and national levels. The results show that smallholder farms occupy up to 40% of agricultural areas globally, which means that, potentially, there are many more smallholder farms in comparison with the two different current global estimates of 12% and 24%. The global field size map and the crowdsourced data set are openly available and can be used for integrated assessment modeling, comparative studies of agricultural dynamics across different contexts, for training and validation of remote sensing field size delineation, and potential contributions to the Sustainable Development Goal of Ending hunger, achieve food security and improved nutrition and promote sustainable agriculture.     

Eye Structure and Vision in the Freshwater Pulmonate Mollusc Planorbarius corneus

The structure of the mollusc Planorbarius corneus eye was studied using light and electron microscopy. The eye consists of the cornea, eye lens of non-spherical shape, and the vitreous body tightly bound to it, as well as of a monolayer non-inverted retina composed of photoreceptor and supporting (pigmented) cells. Its inner surface has two invaginations. The apices of several hundreds of photoreceptors directed to the vitreous body have groups of microvilli with a parallel orientation to each other. The eye optic system places the image into the base of the retinal microvillar layer. Its angle resolution provided by density of distribution of photoreceptor cells and the value of the index F = 1.71 is to be about 2.06° with a correction for the light spreading between microvilli of neighbor cells. Under conditions of a V-shaped labyrinth, the P. corneus molluscs show positive phototaxis by moving to the light source. The angular acuity of vision was assessed from differences in the choice by the molluscs of direction of movement to the pattern of vertical black bands with different periods of alternation. The differential threshold obtained is within an interval of 1.43–1.91°, which is close to the calculated value of angular resolution of the retina.