Brightness illusions drive a neuronal response in the primary visual cortex under top-down modulation.

Brightness illusions are a powerful tool in studying vision, yet their neural correlates are poorly understood. Based on a human paradigm, we presented illusory drifting gratings to mice. Primary visual cortex (V1) neurons responded to illusory gratings, matching their direction selectivity for real gratings, and they tracked the spatial phase offset between illusory and real gratings. Illusion responses were delayed compared to real gratings, in line with the theory that processing illusions requires feedback from higher visual areas (HVAs). We provide support for this theory by showing a reduced V1 response to illusions, but not real gratings, following HVAs optogenetic inhibition. Finally, we used the pupil response (PR) as an indirect perceptual report and showed that the mouse PR matches the human PR to perceived luminance changes. Our findings resolve debates over whether V1 neurons are involved in processing illusions and highlight the involvement of feedback from HVAs.

Assessment of wind energy potential and economic evaluation of four wind turbine models for the east of Iran.

This study examined the potential of wind energy in 22 regions in eastern Iran. In this regard, it investigated the parameters of Weibull, mean wind speed, and wind power density in these areas. The results showed that the mean wind speed was above 4 m/s at all stations and in ten stations was above 5 m/s. Also, the study of monthly wind speed fluctuations in eastern parts of Iran and its comparison with the relevant variations of electricity consumption showed that the fluctuations of speed is clearly in line with the requirements of electrical energy consumption in Iran. In addition, the annual production of energy and the economic performance of four commercial turbine models at 22 sites were investigated. Generally, Mapna 2.5 MW and Vestas V100-1.8 MW 60 turbines were more efficient than the other two turbine models in terms of annual production of energy and cost of producing electricity. The results of the economic analysis showed that investment in wind farms in eastern parts of Iran could be associated with high profitability. Finally, the results of this study indicated that planning to exploit wind energy for electricity production in eastern parts of Iran is an appropriate strategy to reduce Iran's dependence on fossil fuels.

Retraction Note to: Stability of neuronal avalanches and long-range temporal correlations during the first year of life in human infant.

The authors have retracted this article Jannesari et al. (2019) because an incorrect version of the article was published in error. The manuscript has been republished as Jannesari et al. (2020). All authors agree to this retraction.

Stability of neuronal avalanches and long-range temporal correlations during the first year of life in human infants.

During infancy, the human brain rapidly expands in size and complexity as neural networks mature and new information is incorporated at an accelerating pace. Recently, it was shown that single-electrode EEG in preterms at birth exhibits scale-invariant intermittent bursts. Yet, it is currently not known whether the normal infant brain, in particular, the cortex, maintains a distinct dynamical state during development that is characterized by scale-invariant spatial as well as temporal aspects. Here we employ dense-array EEG recordings acquired from the same infants at 6 and 12 months of age to characterize brain activity during an auditory odd-ball task. We show that suprathreshold events organize as spatiotemporal clusters whose size and duration are power-law distributed, the hallmark of neuronal avalanches. Time series of local suprathreshold EEG events display significant long-range temporal correlations (LRTCs). No differences were found between 6 and 12 months, demonstrating stability of avalanche dynamics and LRTCs during the first year after birth. These findings demonstrate that the infant brain is characterized by distinct spatiotemporal dynamical aspects that are in line with expectations of a critical cortical state. We suggest that critical state dynamics, which theory and experiments have shown to be beneficial for numerous aspects of information processing, are maintained by the infant brain to process an increasingly complex environment during development.

Stability of neuronal avalanches and long-range temporal correlations during the first year of life in human infant.

During infancy, the human brain rapidly expands in size and complexity as neural networks mature and new information is incorporated at an accelerating pace. Recently, it was shown that single electrode EEG in preterms at birth exhibits scale-invariant intermittent bursts. Yet, it is currently not known whether the normal infant brain, in particular, the cortex maintains a distinct dynamical state during development that is characterized by scale-invariant spatial as well as temporal aspects. Here we employ dense-array EEG recordings acquired from the same infants at 6 and 12 months of age to characterize brain activity during an auditory oddball task. We show that suprathreshold events organize as spatiotemporal clusters whose size and duration are power-law distributed, the hallmark of neuronal avalanches. Time series of local suprathreshold EEG events display significant long-range temporal correlations (LRTCs). No differences were found between 6 and 12 months, demonstrating stability of avalanche dynamics and LRTCs during the first year after birth. These findings demonstrate that the infant brain is characterized by distinct spatiotemporal dynamical aspects that are in line with expectations of a critical cortical state. We suggest that critical state dynamics, which theory and experiments have shown to be beneficial for numerous aspects of information processing, are maintained by the infant brain to process an increasingly complex environment during development.

Coexistence of Stochastic Oscillations and Self-Organized Criticality in a Neuronal Network: Sandpile Model Application.

Self-organized criticality (SOC) and stochastic oscillations (SOs) are two theoretically contradictory phenomena that are suggested to coexist in the brain. Recently it has been shown that an accumulation-release process like sandpile dynamics can generate SOC and SOs simultaneously. We considered the effect of the network structure on this coexistence and showed that the sandpile dynamics on a small-world network can produce two power law regimes along with two groups of SOs-two peaks in the power spectrum of the generated signal simultaneously. We also showed that external stimuli in the sandpile dynamics do not affect the coexistence of SOC and SOs but increase the frequency of SOs, which is consistent with our knowledge of the brain.

Pentoxifylline Increases Antiadhesion Effect of Streptokinase on Postoperative Adhesion Formation: Involvement of Fibrinolytic Pathway.

Pentoxifylline reduces peritoneal adhesions and increases peritoneal fibrinolysis in rodents. Furthermore, the activation of the fibrinolytic system by streptokinase leading to degradation of fibrin is effective in the prevention of adhesion formation. We have investigated the effects of pentoxifylline and streptokinase alone and/or coadministration on postoperative intra-abdominal adhesion formation in adult female NMRI mice. Drugs were administered from the day of surgery until 10 days after surgery. At relaparotomy 11 days after surgery, the abdomen was opened, and the adhesions were graded in a blinded fashion utilizing the classification system described. Oral gavage administration of lower doses of pentoxifylline (3.125, 6.25, and 12.5 mg/kg) had no significant effect on postsurgical adhesion formation, while the higher doses of pentoxifylline (25 and 50 mg/kg) significantly decreased postsurgical adhesion formation. Moreover, intraperitoneal injection of lower doses of streptokinase (9.375, 18.75, and 37.5 unit/kg, i.p.) had no significant effect on postsurgical adhesion formation, while the higher doses of streptokinase (75 and 150 unit/kg) significantly decreased postsurgical adhesion formation. In other series of experiments, coadministration of lower doses of pentoxifylline and streptokinase doses, which were ineffective when given alone, significantly decreased postsurgical intra-abdominal adhesion formation compared with streptokinase control group. The results suggest that pentoxifylline may interfere with streptokinase in the reduction of postoperative intra-abdominal adhesion formation by enhancing local fibrinolytic activity.

Acute paraplegia after general anesthesia.

Acute paraplegia is a rare but catastrophic complication of surgeries performed on aorta and corrective operations of vertebral column. Trauma to spinal cord after spinal anesthesia and ischemia of spinal cord also may lead to acute paraplegia. Acute paraplegia as a complication of general anesthesia in surgeries performed on sites other than aorta and vertebral column is very rare. Here we present a 56 year old woman with acute paraplegia due to spinal cord infarction after laparoscopic cholecystectomy under general anesthesia probably caused by atherosclerosis of feeding spinal arteries and ischemia of spinal cord after reduction of blood flow possibly due to hypotension during general anesthesia.