Design Space Exploration for Partially Reconfigurable Architectures in Real-Time Systems

International audienceIn this paper, we introduce FoRTReSS (Flow for Reconfigurable archiTectures in Real-time SystemS), a methodology for the generation of partially reconfigurable architectures with real-time constraints, enabling Design Space Exploration (DSE) at the early stages of the development. FoRTReSS can be completely integrated into existing partial reconfiguration flows to generate physical constraints describing the architecture in terms of reconfigurable regions that are used to floorplan the design, with key metrics such as partially reconfigurable area, real-time or external fragmentation. The flow is based upon our SystemC simulator for real-time systems that helps develop and validate scheduling algorithms with respect to application timing constraints and partial reconfiguration physical behaviour. We tested our approach with a video stream encryption/decryption application together with Error Correcting Code and showed that partial reconfiguration may lead to an area improvement up to 38% on some resources without compromising application performance, in a very small amount of time: less than 30 s

Cognitive performances and locomotor activity following dentate granule cell damage in rats: Role of lesion extent and type of memory tested

Intradentate injection of colchicine is one of the techniques used to destroy granule cells. This study compared the behavioral effects of various amounts of colchicine (1.0, 3.0, and 6.0 microg; Col 1, Col 3, and Col 6, respectively) injected into the dentate gyrus of adult Long-Evans male rats. Starting 10 days after lesion surgery, behavioral testing assessed home-cage and open-field locomotion, alternation in a T-maze, water-maze, and radial-maze learning according to protocols placing emphasis on reference, and working memory. All of these tasks are sensitive to hippocampal disruption. Histological verifications showed that the extent of the lesions depends on the dose of colchicine (index of dentate gyrus shrinkage: -33% in Col 1, -54% in Col 3, and -67% in Col 6 rats). Colchicine dose-dependently increased nocturnal home cage activity (an effect found 10 days but not 5 months after surgery), but had no significant effect on open-field locomotion or T-maze alternation. A dose-dependent reference memory impairment was found during the acquisition of spatial navigation in the water maze; Col 3 and Col 6 rats were more impaired than Col 1 rats. During the probe trial (platform removed), control rats spent a longer distance swimming over the platform area than all rats with colchicine lesions. In the working memory version of the test, all rats with colchicine lesions showed significant deficits. The deficits were larger in Col 3 and Col 6 rats compared to Col 1 rats. The lesions had no effect on swimming speed. In the radial-maze test, there was also a dose-dependent working memory impairment. However, reference memory was disrupted in a manner that did not differ among the three groups of lesioned rats. Our data are in line with the view that the dentate gyrus plays an important role in the acquisition of new information and is an integral neural substrate for spatial reference and spatial working memory. They also suggest that damage to granule cells might have more pronounced effects on reference than on working memory in the radial maze. Finally, they demonstrate that part of the variability in the conclusions from previous experiments concerning the role of granule cells in cognitive processes, particularly in spatial learning and memory, may be due to the type of tests used and/or the extent of the damage produced

Intraseptal infusions of 8-OH-DPAT in the rat impairs water-maze performances: effects on memory or anxiety?

In the rat, 5-HT1A receptors are found on medial septal cholinergic neurons. The effects of intraseptal infusions of the 5-HT1A receptor agonist 8-OH-DPAT (8-hydroxy-2-(di-n-propyl-amino)-tertralin) were assessed on reference memory performances in a water maze. Compared with vehicle infusions, 0.5 and 4 microg of 8-OH-DPAT significantly impaired (but did not prevent) acquisition of the task and probe-trial performances. The results suggest that activation of 5-TH1A receptors in the (medial) septal area impairs spatial learning, perhaps directly by reducing the hippocampal cholinergic tonus, or indirectly by an effect on anxiety

Effects of 192 IgG-saporin on acetylcholinesterase histochemistry in male and female rats

Sex hormones may exert neuroprotective effects in various models of brain lesions. Male and female Long-Evans rats were subjected to intracerebroventricular injections of 2 microg 192 IgG-saporin or vehicle. Starting 2 days before surgery, half the male rats were treated with estradiol for 7 days. Three weeks after surgery, they were sacrificed for histochemical staining of acetylcholinesterase (AChE) and densitometric evaluations. The lesion induced a substantial to dramatic decrease of the AChE-positive fiber density in the cingulate, somatosensory, piriform, retrosplenial and perirhinal cortices, and in the hippocampus. Weak effects were found in the striatum. There was no significant decrease in the dorsal thalamus. Sex had no significant effect on AChE-positive staining in any brain area. In males, estradiol treatment did not alter the effects of 192 IgG-saporin. These results show that sex or estradiol treatment in male rats does not interfere with the immunotoxic effects of intracerebroventricular injections of 192 IgG-saporin on cholinergic projections from the basal forebrain

When injected into the fimbria-fornix/cingular bundle, not in the raphe, 5,7-dihydroxytryptamine prevents amphetamine-induced hyperlocomotion

The locomotor effects of acute amphetamine treatment (1 mg/kg, i.p.) were assessed in Long-Evans rats after 5,7-dihydroxytryptamine (5, 7-DHT) injections into the fimbria-fornix/cingular bundle (FiFx/CB; 4 microg/side), or the dorsal and median raphe (Raphe; 10 microg). In control rats, amphetamine induced a significant increase of home-cage activity for about 2 h. This effect was similar in Raphe rats, but was absent in FiFx/CB rats. The raphe lesions reduced serotonin concentrations by 50% in the dorsal hippocampus, 75% in the ventral hippocampus and 58% in the fronto-parietal cortex. After FiFx/CB lesions, the reduction amounted 50, 61 and only 25%, in each of these regions, respectively. In the fronto-partietal cortex, dopamine concentration was significantly decreased in Raphe (-27%) and FiFx/CB rats (-65%). The results suggest that a serotonergic denervation of the hippocampus by injections of 5,7-DHT into the FiFx/CB pathways hampers the stimulating effects of amphetamine on locomotor activity. This effect might be related to the reduced dopaminergic tone in the fronto-parietal cortex

Effects of MDL 73005 on water-maze performances and locomotor activity in scopolamine-treated rats

The stimulation of 5-HT1A receptors in the raphe or their blockade in the hippocampus can reduce cognitive deficits induced by blockade of muscarinic receptors in the hippocampus. We investigated the effects of MDL 73005 (8-[2-(2,3-dihydro-1,4-benzodioxin-2-ylmethylamino) ethyl]-8-azaspiro[4,5] decane-7,9-dione methyl sulphonate), an agonist at 5-HT1A somatodendritic autoreceptors and an antagonist at postsynaptic 5-HT1A receptors in rats treated systemically with scopolamine. Spatial memory was assessed in a water maze using protocols testing reference and working memory. Home cage locomotor activity was also determined. Working memory and locomotor activity were evaluated before and after para-chlorophenylalanine (pCPA) treatment. Scopolamine produced a weak impairment of reference memory at 0.5 mg/kg, and a more pronounced impairment of working memory at 0.25 and 0.5 mg/kg. MDL 73005 alone (2 mg/kg, i.p.) had no effect, but prevented the memory impairments induced by 0.25 mg/kg of scopolamine. Scopolamine induced hyperlocomotion. MDL 73005 alone did not affect locomotor activity, but exacerbated the hyperlocomotion induced by 0.5 mg/kg of scopolamine. pCPA did not abolish the effects of MDL 73005, suggesting that these effects were not due to an action at presynaptic receptors, or even that they involved receptors other than serotonergic ones (e.g., D2). In conclusion, MDL 73005 is able to antagonise moderate spatial memory dysfunctions induced by systemic muscarinic blockade

Combined 192 IgG-saporin and 5,7-dihydroxytryptamine lesions in the male rat brain

In a previous experiment [Eur J Neurosci 12 (2000) 79], combined intracerebroventricular injections of 5,7-dihydroxytryptamine (5,7-DHT; 150 microg) and 192 IgG-saporin (2 microg) in female rats produced working memory impairments, which neither single lesion induced. In the present experiment, we report on an identical approach in male rats. Behavioral variables were locomotor activity, T-maze alternation, beam-walking, Morris water-maze (working and reference memory) and radial-maze performances. 192 IgG-saporin reduced cholinergic markers in the frontoparietal cortex and the hippocampus. 5,7-DHT lesions reduced serotonergic markers in the cortex, hippocampus and striatum. Cholinergic lesions induced motor deficits, hyperactivity and reduced T-maze alternation, but had no other effect. Serotonergic lesions only produced hyperactivity and reduced T-maze alternation. Beside the deficits due to cholinergic lesions, rats with combined lesions also showed impaired radial-maze performances. We confirm that 192 IgG-saporin and 5,7-DHT injections can be combined to produce concomitant damage to cholinergic and serotonergic neurons in the brain. In female rats, this technique enabled to show that interactions between serotonergic and basal forebrain cholinergic mechanisms play an important role in cognitive functions. The results of the present experiment in male rats are not as clear-cut, although they are not in obvious contradiction with our previous results in females

Intraseptal injection of the 5-HT1A/5-HT7 agonist 8-OH-DPAT and working memory in rats

RATIONALE: In rats, 5-HT(1A) receptors are present in the septal region, e.g. on cholinergic neurons of the medial septum, where they might be a substrate for cognitively relevant interactions between cholinergic and serotonergic systems. OBJECTIVE: The present experiment assessed the effects of the stimulation of septal 5-HT(1A) receptors on spatial working memory. METHODS: Stimulation of septal 5-HT(1A) receptors was carried out by infusions targetting the medial septum of the 5-HT(1A)/5-HT(7) receptor agonist 8-hydroxy-2-(di-n-propyl-amino)-tetralin (8-OH-DPAT; 0.5 or 4 microg). Spatial memory was assessed in a water maze using a protocol placing emphasis on spatial working memory. The location of the hidden platform was changed every day and performance was assessed on two consecutive trials each day. RESULTS: In comparison to vehicle injections, the intraseptal infusion of 4 microg 8-OH-DPAT impaired performance significantly: rats treated with 8-OH-DPAT exhibited increased distances to reach the hidden platform on both trials 1 and 2. Rats infused with 0.5 microg showed similar changes that failed to be significant. Such effects were not observed when the platform was visible. CONCLUSIONS: These results extend those of a previous experiment which showed that intraseptal injections of 8-OH-DPAT impaired spatial reference memory. Based on the characteristics of the observed deficits, it is suggested that the 8-OH-DPAT-induced impairment, rather than being only the result of a true alteration of working memory, might reflect a more global cognitive deficiency in which alteration of general memory capacities may be biased by disrupted search strategies/exploration and/or dysfunctions of attention

Selective immunolesions of CH4 cholinergic neurons do not disrupt spatial memory in rats

Adult male Long-Evans rats were subjected to bilateral lesions of the cholinergic neurons in the nucleus basalis magnocellularis (NBM) by injection of 0.2 or 0.4 microg 192-IgG-saporin in 0.4 microl phosphate-buffered saline. Control rats received an equivalent amount of phosphate-buffered saline. Starting 2 weeks after surgery, all rats were tested for locomotor activity in their home cage, beam-walking performance, T-maze alternation rates (working memory), reference and working memory performance in a water-maze task, and memory capabilities in the eight-arm radial maze task using uninterrupted and interrupted (delay of 2 min, 2 h and 6 h after four arms had been visited) testing procedures. Histochemical analysis showed a significant decrease of acetylcholinesterase (AChE)-positive reaction products (30-66%) in various cortical regions at the 0.2-microg dose. At the dose of 0.4 microg, there was an additional, although weak, damage to the hippocampus (17-30%) and the cingulate cortex (34%). The behavioral results showed only minor impairments in spatial memory tasks, and only during initial phases of the tests (reference memory in the water maze, working memory in the radial maze). The behavioral effects of the dramatic cholinergic lesions do not support the idea of a substantial implication of cholinergic projections from the NBM to the cortex in the memory processes assessed in this study, but they remain congruent with an involvement of these projections in attentional functions

PathEx: a novel multi factors based datasets selector web tool

<p>Abstract</p> <p>Background</p> <p>Microarray experiments have become very popular in life science research. However, if such experiments are only considered independently, the possibilities for analysis and interpretation of many life science phenomena are reduced. The accumulation of publicly available data provides biomedical researchers with a valuable opportunity to either discover new phenomena or improve the interpretation and validation of other phenomena that partially understood or well known. This can only be achieved by intelligently exploiting this rich mine of information.</p> <p>Description</p> <p>Considering that technologies like microarrays remain prohibitively expensive for researchers with limited means to order their own experimental chips, it would be beneficial to re-use previously published microarray data. For certain researchers interested in finding gene groups (requiring many replicates), there is a great need for tools to help them to select appropriate datasets for analysis. These tools may be effective, if and only if, they are able to re-use previously deposited experiments or to create new experiments not initially envisioned by the depositors. However, the generation of new experiments requires that all published microarray data be completely annotated, which is not currently the case. Thus, we propose the PathEx approach.</p> <p>Conclusion</p> <p>This paper presents PathEx, a human-focused web solution built around a two-component system: one database component, enriched with relevant biological information (expression array, omics data, literature) from different sources, and another component comprising sophisticated web interfaces that allow users to perform complex dataset building queries on the contents integrated into the PathEx database.</p