Academic literature on the topic 'Shunting inhibition'

With the ever-increasing utilization of imagery in scientific, industrial, civilian, and military applications, visual pattern recognition has been thriving as a research field and has become an essential enabling technology for many applications. In this chapter, we present a brain-inspired pattern recognition architecture that can easily be adapted to solve various real-world visual pattern recognition tasks. The architecture has the ability to extract visual features from images and classify them within the same network structure; in other words, it integrates the feature extraction stage with the classification stage, and both stages are optimized with respect to one another. The main processing unit for feature extraction is governed by a nonlinear biophysical mechanism known as shunting inhibition, which plays a significant role in visual information processing in the brain. Here, the proposed architecture is applied to four real-world visual pattern recognition problems; namely, handwritten digit recognition, texture segmentation, automatic face detection, and gender recognition. Experimental results demonstrate that the proposed architecture is very competitive with and sometimes outperforms existing state-of-the-art techniques for each application.

The essential amino acid tryptophan is degraded primarily by the kynurenine pathway, a cascade of enzymatic steps leading to the generation of several neuroactive compounds. Of those, kynurenic acid (KYNA), an antagonist at N-methyl-D-aspartate (NMDA) and alpha7-nicotinic receptors, has gained much attention in schizophrenia research. The concentrations of both KYNA and its precursor, kynurenine, have been repeatedly found significantly elevated both in the postmortem cerebral cortex and in the cerebrospinal fluid of schizophrenia persons as compared to healthy control subjects. Studies in experimental animals have demonstrated that KYNA tightly controls dopaminergic, cholinergic, glutamatergic, and GABAergic neurotransmission, and elevated brain levels appear related to psychotic symptoms and cognitive impairments. The kyurenine pathway is highly inducible by immune activation, and studies have shown that the pro-inflammatory cytokines interleukin (IL)-1β‎ and IL-6 are elevated in schizophrenia and stimulate the production of KYNA. Another mechanism that may account for the abnormally high central kynurenine and KYNA levels seen in schizophrenia might be the observed reduced expression and activity of the enzyme kynurenine 3-monooxygenase (KMO), shunting the synthesis of kynurenine toward KYNA. In line with these studies and concepts, preclinical results suggest that inhibition of kynurenine aminotransferase (KAT) II, by reducing the synthesis and function of KYNA in the brain, offers a novel approach to ameliorate psychosis and to improve cognitive performance in persons with schizophrenia.

Thromboxane release from platelet microemboli during major arterial surgery may mediate depression of cardio-pulmonary function. The effect of cyclo-oxygenase inhibition by aspirin has been studied in a porcine model of aortic surgery.Following autologous platelet labelling with 111-lndium, 24 pigs (20-25kg) were randomised to low dose (LD) aspirin (0.5mg/kg), high dose (HD) aspirin (10mg/kg) or placebo.Arterial and Swann Ganz catheters were inserted prior to surgery consisting of midline laparotomy, small bowel extériorisation, 1.5 hours of aortic clamping and 1 hour shock before resuscitatio

The aims of the study were to determine the nature of the procoagulant activity present in the ascitic fluid and the means to inhibit the thrombotic complications appearing after peritoneovenous shunting. In a prospective study, 10 ascitic fluids (5 exsudates, 5 transsudates) were studied. The procoagulant activity was defined as the capacity of ascitic fluid to shorten the recalcification time of a control plasma.Our results showed :1. All the ascitic fluids exhibited a procoagulant activity.2. The procoagulant activity of the cellular fraction was related to the presence of platelet factor 3