Dynamic divisive normalization circuits explain and predict change detection in monkey area MT

Sudden changes in visual scenes often indicate important events for behavior. For their quick and reliable detection, the brain must be capable to process these changes as independently as possible from its current activation state. In motion-selective area MT, neurons respond to instantaneous speed changes with pronounced transients, often far exceeding the expected response as derived from their speed tuning profile. We here show that this complex, non-linear behavior emerges from the combined temporal dynamics of excitation and divisive inhibition, and provide a comprehensive mathematical analysis. A central prediction derived from this investigation is that attention increases the steepness of the transient response irrespective of the activation state prior to a stimulus change, and irrespective of the sign of the change (i.e. irrespective of whether the stimulus is accelerating or decelerating). Extracellular recordings of attention-dependent representation of both speed increments and decrements confirmed this prediction and suggest that improved change detection derives from basic computations in a canonical cortical circuitry.

Prior expectations in visual speed perception predict encoding characteristics of neurons in area MT

Bayesian inference provides an elegant theoretical framework for understanding the characteristic biases and discrimination thresholds in visual speed perception. However, the framework is difficult to validate due to its flexibility and the fact that suitable constraints on the structure of the sensory uncertainty have been missing. Here, we demonstrate that a Bayesian observer model constrained by efficient coding not only well fits extensive psychophysical data of human visual speed perception but also provides an accurate quantitative account of the tuning characteristics of neurons known for representing visual speed. Specifically, we found that the population coding accuracy for visual speed in area MT ("neural prior") is precisely predicted by the power-law, slow-speed prior extracted from fitting the Bayesian model to the psychophysical data ("behavioral prior"), to the point that they are indistinguishable in a model cross-validation comparison. Our results demonstrate a quantitative validation of the Bayesian observer model constrained by efficient coding at both the behavioral and neural levels.

OPTIMASI PENGELOLAAN AIR BENDUNG CAWAK UNTUK DAERAH IRIGASI CAWAK DENGAN PROGRAM SOLVER (Studi kasus : Kemanteren Nglumber_Kecamatan Kepohbaru_Kabupaten Bojonegoro)

Bendung Cawak is located in the district of Kepohbaru, Bojonegoro. Bendung Cawak is used for irrigation and water supplies of Kepohbaru, water availability is insufficient, while the amount of land and also residents who need water, so optimization Bendung Cawak is necessary for the water pitcher bendung can be optimized according to the needs.In this study, to maximize the area of land irrigated area to be optimized. In the optimization model used is the optimization of the monthly for 1 year by calculating the area of irrigated land available, land irrigation is met, the greater availability of water and irrigation needs are met. Optimization method used in this calculation is Program Solver.The results obtained by the reliable discharge available in the Cawak dam reservoir are 2.547 m3 / second. The need for irrigation water with the cropping pattern of Palawija-Padi-Padi at the beginning of planting in August I is 0.579 l / sec / ha as a planting plan with the minimum water requirements. As well as optimization, the optimum cropping pattern and initial planting are August I with the Palawija-Padi-Padi planting intensity 291% and with irrigation area MT I 675 ha, MT II 742 ha, MT III 742 ha. AbstrakBendung Cawak terletak di Kecamatan Kepohbaru, Kabupaten Bojonegoro. Layanan Bendung Cawak dipergunakan untuk keperluan irigasi di Daerah Irigasi Cawak Kecamatan Kepohbaru, ketersediaan air yang tidak mencukupi sedangkan banyaknya lahan yang membutuhkan air , sehingga Optimasi Bendung Cawak sangat diperlukan agar air tampungan Bendung dapat dioptimalkan sesuaidengan kebutuhan.Pada studi ini, untuk memaksimalkan luas lahan irigasi dilakukan optimasi luas lahan irigasi . Dalam model optimasi yang digunakan adalah optimasi satu bulanan selama 1 tahun dengan memperhitungkan luas lahan irigasi yang tersedia, luas lahan irigasi yang terpenuhi, besarnya ketersediaan debit air maksimal, dan kebutuhan air irigasi yang dipenuhi. Metode optimasi yang digunakan dalam perhitungan ini yaitu Program Solver.Hasil yang diperoleh debit andalan yang tersedia di tampungan bendung cawak adalah 2,547 m3/detik. kebutuhan air irigasi dengan pola tanam Palawija-Padi-Padi awal tanam Agustus I itu sebesar 0,579 lt/dtk/ha sebagai rencana tanam dengan kebutuhan air paling minimum.Serta optimasi didapatkan pola tanam dan awal tanam yang paling optimum adalah Agustus I dengan pola tanam Palawija-Padi-Padi intensitas tanam 291% dan dengan luas areal irigasi MT I 675 ha, MT II 742 ha, MT III 742 ha.

Visual Cortical Area MT is Required for Development of the Dorsal Stream and Associated Visuomotor Behaviours

The middle temporal (MT) area of the extrastriate visual cortex has long been studied in adulthood for its distinctive physiological properties and function as a part of the dorsal stream, yet interestingly possesses a similar maturation profile as the primary visual cortex (V1). Here we examined whether an early-life lesion of MT altered the dorsal stream development and the behavioural precision of reaching to grasp sequences. We observed permanent changes in the anatomy of cortices associated with both reaching (PE and MIP) and grasping (AIP), as well as in reaching and grasping behaviours. In addition, we observed a significant impact on the anatomy of V1 and the direction sensitivity of V1 neurons in the lesion projection zone. These findings indicate that area MT is a crucial node for the development of the primate vision, impacting both V1 and areas in the dorsal visual pathway known to mediate visually guided manual behaviours.TeaserThe early life loss of visual area MT leads to significant anatomical, physiological and behavioural changes.