Phenotypic methods have traditionally been used to identify clini

Phenotypic methods have traditionally been used to identify clinically important Mucor spp. (Wang et al., 1990; Fingeroth et al., 1994; Chandra & Woodgyer, 2002). However, the fact that most published reports refer only to the genus Mucor underlines the difficulties in species identification (Ribes et al., 2000). Although observation of zygospores enhanced the identification of heterothallic Zygomycetes (Weitzman et al., 1995; Iwen et al., 2005), maintaining a library of tester strains is not easy for many laboratories and mating tests do not always yield a positive result (Schipper, 1976; Sigler et al., 2002). The Mucor isolate FM07 in yellow catfish was more like oomycete

species or some other filamentous fungi by gross examination. Under the microscope,

uniform nonseptate, broad and right-angled Lapatinib concentration branched hyphae, globose sporangia and sporangiophores could be seen. Based on the morphological characteristics, the strain FM07 was identified as M. circinelloides. Interestingly, the ITS rRNA gene fragment of FM07 showed 100% similarity to both M. circinelloides (EF583641) and Rhizomucor variabilis (DQ118990). Voigt et al. (1999) found R. variabilis was phylogenetically very close to Mucor spp. However, R. variabilis has rhizoids and stolons and can grow well above 40 °C. These characteristics are very different from those of Mucor Selumetinib spp. and were not found in strain FM07. The results identified strain FM07 as M. circinelloides. Infection trials showed that strain FM07 was pathogenic for yellow catfish by intraperitoneal and wound infection. However, the trials also revealed some differences between the two routes of infection (cf. results in Table 1). When the concentrations of sporangiospore suspension were increased, the cumulative mortality from different concentration groups went up correspondingly (30%, 45% and 90%) and the time to death of fish was

reduced (45, 28 and 19 days) in intraperitoneal crotamiton infection. In wound infection, the beginning time of death of fish from different concentration groups was similar to that in the intraperitoneal infection group, but the cumulative mortality was 100% in all wounded groups. In both experiments, when the concentration of sporangiospore suspension was increased the infected fish died more quickly. In immersion infection, there were no fish dead, although the strain FM07 was isolated from the mucus of some fish. These results suggest M. circinelloides is pathogenic to yellow catfish if a portal of entry is provided. Their infection may be associated with some primary pathogenic factor, for example trauma such as wound infection or poor environmental conditions. This phenomenon was consistent with the disease caused by M. circinelloides in humans (Chandra & Woodgyer, 2002; Iwen et al., 2007). In these cases, although M. circinelloides was reported as primary cutaneous zygomycosis, the patients all were known or suspected to have been exposed to trauma in different parts of body.

, 2001; Björkroth & Holzapfel, 2006; van Hijum et al, 2006) Glu

, 2001; Björkroth & Holzapfel, 2006; van Hijum et al., 2006). Glucan synthesis is catalyzed from sucrose by secreted or cell-anchored glucansucrases, which convert the sucrose substrate into high-molecular-weight polymers, STA-9090 in vitro with the concomitant release of fructose (Monsan et al., 2001; van Hijum et al., 2006). These reactions occur without any other cofactor; the energy of the osidic bond of sucrose enables the efficient transfer of a glucosyl residue via the formation of a covalent glycosyl-enzyme

intermediate allowing the elongation of polymer chains (Moulis et al., 2006; van Hijum et al., 2006). In addition, these enzymes also produce oligosaccharides when acceptor molecules such as maltose are present in the reaction mixture along with sucrose (Monsan et al., 2001; Korakli & Vogel, 2006). Glucansucrases (EC – also referred as glucosyltransferases (GTF) – are relatively large extracellular enzymes showing an average molecular weight of 170 kDa. They belong to the glycoside hydrolase (GH) family 70 ( Depending on the type

of glucosidic linkages as well as the degree and organization of branching, glucansucrases can be classified into different categories (Monsan et al., 2001; van Hijum 3-MA supplier et al., 2006). Among them are found dextransucrases, which produce dextran, a polymer with a linear backbone made of at least 50%α-(16) glucosidic bonds and α-(12)-, α-(13)- or α-(14)-linked branches. More than 40 genes encoding GH70 glucansucrases have been isolated and sequence analyzed. Deduced amino acid sequence analysis revealed a signal peptide and a common structural organization with (1) an N-terminal Astemizole variable domain; (2) a conserved catalytic domain of about 1000 amino acids; and (3) a C-terminal domain of variable length,

which is thought to be involved in glucan binding (Korakli & Vogel, 2006; van Hijum et al., 2006). Weissella genus is phylogenetically related to Leuconostoc and Oenococcus and arose from the reclassification of Leuconostoc paramesenteroides and some related ‘atypical’ heterofermentative lactobacilli (Collins et al., 1993). Weissella cibaria and Weissella confusa are rod-shaped obligate heterofermentative species, which are closely related in the genus (Björkroth et al., 2002; Björkroth & Holzapfel, 2006). These two species have been isolated from a wide variety of fermented products of plant origin (Björkroth et al., 2002; Camu et al., 2007; Kostinek et al., 2007; Chao et al., 2008), in particular from sourdough (De Vuyst et al., 2002; Catzeddu et al., 2006; Valmorri et al., 2006; Iacumin et al., 2009; Robert et al., 2009). They were also occasionally found in dairy products (van der Meulen et al., 2007; Ouadghiri et al., 2009). Additionally, W. cibaria was reported as a member of the human saliva LAB microbial communities (Kang et al., 2006).

[36] Baricitinib is currently in phase 3 trials for RA VX-509 is

[36] Baricitinib is currently in phase 3 trials for RA. VX-509 is a selective JAK3 inhibitor currently in phase 2 and 3 investigation in the treatment of RA. Phase 2 studies compared 12 weeks of VX-509 monotherapy to placebo in patients who had failed a non-biologic DMARD. A significant response based on ACR20 and DAS28-CRP was seen with VX-509 dosed above 50 mg twice daily. Serious infections were noted, including a case of tuberculosis and pneumonia. As seen with tofacitinib and JAK3 inhibition, elevations in LDL,

HDL and transaminases were reported. No effect was seen on hemoglobin, neutrophils or creatinine.[37] GLPG0634 is a selective JAK1 inhibitor. Conceptually, this might lead to anti-inflammatory effects of IL-6 reduction without the side-effect profile of JAK2 and JAK3 inhibition. A 4-week phase 2a trial was performed Bcl-2 inhibitor review on 36 RA patients comparing GLPG0634 to placebo in those with inadequate response to MTX. A statistically significant response was seen in ACR20, DAS28 and CRP. Mild decreases in neutrophils and platelets counts were reported

without TSA HDAC molecular weight effects on hemoglobin, LDL, creatinine or transaminases.[38] A larger phase 2a study confirmed the efficacy previously seen as well as the safety profile.[39] Phase 2b trials were scheduled to start in 2013. Spleen tyrosine kinase (Syk) is another intracellular cytoplasmic tyrosine kinase. Syk has generated interest in the rheumatology community because it is downstream

from the B cell receptor and Fc receptors, which have integral roles in immunoreceptor signaling for macrophages, neutrophils, mast cells and B cells.[40, 41] Additionally, Syk plays an important role in osteoclast development and bone remodeling, adding to its attraction as a target for inhibition in RA treatment.[42] Syk is expressed in the RA synovial tissue and mediates TNF-α-induced production of cytokines such as IL-6 and metalloproteinase.[43] Fostamatinib (R788) is a Syk inhibitor that showed superiority over placebo in attaining ACR20, ACR50, ACR70 and DAS28 responses in a phase 2a trial of patients failing MTX.[44] Ergoloid In a second, 6-month phase 2 trial, fostamatinib continued to show efficacy over placebo in RA patients on background MTX, with statistically significant improvements in ACR20, ACR50, ACR70 and DAS28 responses at 100 mg twice daily and 150 mg daily dosing regimens. Side-effects included diarrhea, neutropenia and transaminitis. Hypertension was also noted as an adverse event, although patients responded to anti-hypertensive therapy with subsequent normalization of blood pressure.[45] A subsequent phase 2 study of fostamatinib 100 mg twice daily in patients with an incomplete response to biologic therapy failed to demonstrate efficacy based on ACR response criteria. A difference was reported on CRP levels and magnetic resonance imaging synovitis score despite the lack of clinical response.

2) Interestingly, the UV survival curve of the infectious B bur

2). Interestingly, the UV survival curve of the infectious B. burgdorferi 297 (clone BbAH130) wild-type strain used in the present study was likely similar to that of the infectious B. burgdorferi B31 clone (5A18NP1) used by Lin et al. (2009), but was distinctly different from that reported for the infectious B. burgdorferi B31M1 strain studied by Liveris et al. (2004, 2008). The reason for this difference is at present unclear, but may be strain-related, because the BKM120 design of our experiments and those of Liveris and colleagues was otherwise identical. In vitro growth of B. burgdorferi uvrA inactivation mutants was

inhibited by ROS but not by RNS. Dissociation of in vitro susceptibility to ROS and RNS has been reported to occur in a M. tuberculosis uvrB mutant (Darwin & Nathan, 2005). In this case, the mutant was IDH inhibition more susceptible to RNS than the wild-type parent

but showed similar susceptibility to ROS. It was not possible to examine the in vivo function of B. burgdorferi uvrABbu because ΔuvrABbu and its derivatives, in contrast to the parental strain, lacked lp25 (Purser & Norris, 2000; Iyer et al., 2003) (data not shown) and were noninfectious. Studies are currently underway to develop an infectious uvrA inactivation mutant in order to examine its in vivo virulence. Several lines of evidence suggest that the ability of B. burgdorferi to overcome DNA damage following phagocytosis is critical to its ability to survive and produce disease in the host. Mutants of mutS and mutS-II, genes whose products are involved in DNA mismatch repair, display decreased infectivity in Fludarabine immunocompetent mice (Lin et al., 2009). Furthermore, resistance of B. burgdorferi to rapid killing in vitro by phagocytes has been correlated with in vivo infectivity (Georgilis et al., 1991). Although the majority of phagocytosed borrelia are rapidly killed after ingestion, some remain viable

and cultivable (Montgomery et al., 1993), and can stimulate a phagocytic oxidative burst (Georgilis et al., 1991). Plausibly, these few viable organisms could be sufficient to initiate infection of the mammalian host. In summary, homologous recombination and extrachromosomal complementation have been used to show that uvrABbu is needed to repair DNA damage in B. burgdorferi exposed in vitro to UV, ROS and MMC but not in B. burgdorferi exposed to RNS or low pH. M.S. and L.B.I. contributed equally to this work, which was supported by grant R01 AI 048856 to F.C.C. We would like to thank Dr M. Norgard, University of Texas Southwestern Medical Center, Dallas, TX, for providing B. burgdorferi 297 and clone BbAH130. We also thank Dr Julia Bugrysheva for advice. Figure S1. Confirmation of DNA structure and expression of mRNA in Borrelia burgdorferi 297 and derivatives. Please note: Wiley-Blackwell is not responsible for the content or functionality of any supporting materials supplied by the authors.

To investigate this possibility, we first examined the sensitivit

To investigate this possibility, we first examined the sensitivity of the mutant cells to hyper- and hypo-osmotic conditions. As shown in Fig. 2a, the growth rate of mutants was about twofold reduced in hypoosmotic medium (LB without NaCl), whereas the effect of hyperosmotic medium (LB with 0.4 M NaCl) on mutant cells was smaller. In contrast, the

growth rate of the deletion mutants of surA that encodes a periplasmic chaperon was drastically reduced in hyperosmotic medium, but only mildly under hypo-osmotic pressure. The surA gene product is important for the synthesis of OMPs (Lazar & Kolter, 1996; Rouvière & Gross, 1996) and its mutant showed a synthetic lethal phenotype with ΔrodZ (Niba et al., 2007). Furthermore, ERK inhibitor research buy the culture of ΔrodZ mutant cells showed a sharp decline in OD600 nm when diluted with water instead of LB medium (Fig. 2b), whereas this was not observed with ΔsurA and wild-type cells. This strongly indicates that ΔrodZ cells are spheroplast like. However, this phenotype was less evident in stationary-phase cultures, which may be due to the physiological change of mureins associated with the growth stage or nutritional starvation (Goodell & Tomasz, 1980; Glauner et al., 1988). To further clarify whether peptidoglycan of the mutant cells was defective, we quantified peptidoglycan of the mutant

and wild-type cells using SLP reagent. The amount of peptidoglycan in the ΔrodZ mutant was calculated to be about 20% of the wild type (Table 2), a value well below 50% at which no detectable morphological

find more Nintedanib (BIBF 1120) change or slow growth was observed (Prats & de Pedro, 1989). This strongly indicates that the defective synthesis of peptidoglycan was the reason why the ΔrodZ mutant was very sensitive to hypo-osmotic pressure and exhibited significant cell lysis in liquid culture. The severe reduction of peptidoglycan observed with the ΔrodZ mutant was, however, less apparent in a later growth stage as in the case of the spheroplast-like phenotype described above, which seems to suggest that the ΔrodZ mutant is basically able to synthesize peptidoglycan, but is unable to coordinate it with cell growth. On the chromosome of E. coli and most of proteobacteria, rodZ is followed by ispG, an essential gene for isoprene synthesis. Because isoprene is required for the biosynthesis of peptidoglycan (Bouhss et al., 2008), the above results might support an idea that rodZ is functionally related to ispG. Therefore, we first investigated whether rodZ and ispG are transcribed together or not using lacZ fusion constructs, prodZ-1 and prodZ-2 (Fig. 3). The results showed that this was indeed the case and ispG is mostly expressed from the promoter located upstream of rodZ, although a minor transcription activity was still observed when this promoter was eliminated in prodZ-2 (Table 3).

Anal samples were obtained by introducing a cytobrush (Eurogine S

Anal samples were obtained by introducing a cytobrush (Eurogine SL, Sant Boi del Llobregat, Spain) into the anal canal to a depth of 3 cm and gently rotating for 30–45 seconds. The cytobrush was included and shaken into a solution of 20 mL of PreservCyt/ThinPrep Pap test (Cytyc Iberia SL, Barcelona, Spain) for 30 seconds and the solution was stored at −20°C until analysis. DNA was extracted from cell suspensions (in ThinPrep Pap solution) using the Qiamp Viral DNA kit (Qiagen, Hilden, Germany). HPV detection and typing were PD0325901 performed on all samples using a commercial In Vitro Diagnostics with the CE mark certification (IVD-CE) marked assay: the Multiplex Fluorescent-PCR

Kit for Human Papilloma Virus Genotyping (F-HPV typing™; Molgentix SL, Barcelona, Spain) in accordance with the manufacturer’s instructions [20]. The kit allows the detection of 13 HR HPV genotypes: 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59 and 68; and the two most frequent LR HPV genotypes: 6 and 11. A human short tandem repeat (STR) sequence

included in the same multiplex reaction was amplified as an internal control for DNA integrity and absence of PCR inhibitors. Products selleck compound were analysed by capillary electrophoresis on an ABI 3130 XL genetic analyser and using GeneMapper 4.0 software (Applied Biosystems, City Foster, CA). Each PCR run included HPV-positive and -negative controls. Particular care was taken to prevent

carry-over contamination by separating pre- and post-PCR areas in the laboratory. Cytological changes were classified according to the Bethesda System: atypical squamous cells of uncertain significance (ASCUS) and low- and high-grade squamous intraepithelial lesions (LSILs and HSILs, respectively). Samples were independently Wilson disease protein assessed by two expert cytopathologists. Baseline characteristics were summarized with standard descriptive statistics and a descriptive analysis was carried out. The prevalences of overall anal HPV infection, HPV type-specific infection, and cytological diagnoses were estimated. Differences between groups were evaluated using the χ2 test for qualitative variables, and odds ratios (ORs) and their 95% confidence intervals (95% CIs) were calculated. Bivariate and multivariate logistic (for HPV infection) and nominal (for cytological changes) regression models were used where appropriate. For the multivariate analyses, factors with P < 0.2 in the bivariate model or clinical relevance were used to assess interactions in the multivariate regression model. A P-value ≤ 0.05 was considered statistically significant. Data analysis was carried out using spss version 15.0 statistical software (SPSS, Chicago, IL). The CARH·MEN cohort comprised 733 patients recruited from January 2005 to May 2009.

44 Increasingly, experts also consider parts of the Rift Valley i

44 Increasingly, experts also consider parts of the Rift Valley in Africa, including Darfur, Western Kenya, parts of Western Tanzania, Rwanda, Burundi, and Malawi, to pose as many risks as the traditional meningitis belt,47 but not the usual safari tourist destinations in East Africa. Recommendations may also slightly differ based on risk of exposure to PLX4032 ic50 meningococcal disease in the high-risk destination countries as described in the paragraph below. A meningococcal vaccine that covers all four serogroups (ACWY) is necessary for travelers to the African meningitis belt due to the need to protect against multiple

serogroups that cause disease in the area.41 Besides

the general destination-specific factors, we must also consider that personal exposure, living conditions, and professional and social behavior play a decisive role. Disaster relief personnel or staff for humanitarian aid (eg, in refugee camps) may be at higher risk. In the African meningitis belt, any health professional should consider not only the duration of exposure, but also whether there will be close contact Olaparib price to the local population in the activity, the accommodations, and type of public transportation. Globally, exposure in dormitories or similar accommodations may pose an increased risk of transmission, and meningococcal vaccination ought at least to be considered. Finally, host factors need to be taken into account. There is consensus that, for instance, persons with splenectomy and some with immune or complement deficiencies should receive meningococcal vaccination regardless of travel.45,47

Lck This factor is often neglected, and thus a pretravel consultation is an opportunity for catch-up vaccination in such patients; however, HIV infection is not an indication for meningococcal vaccination, although such patients “may elect vaccination.”48 Possibly these patients may only have received a vaccine against serogroup C and may request quadrivalent protection. Some health care professionals will also consider that children are at higher risk of exposure and/or that senior travelers may be immunosenescent and thus at higher risk of serious illness. As with many other immunization programs in the general population, the goal of vaccinating travelers is to both protect the individual from meningococcal disease and protect society from its spread. In view of the large variety of geographical distribution worldwide, broad coverage against all vaccine-preventable serogroups is warranted and therefore multivalent meningococcal vaccines are to be preferred over monovalent vaccines for travelers.

Each of these reorganizing principles applies at some point, thou

Each of these reorganizing principles applies at some point, though they do not represent a necessary

condition induced by the aging process itself. Rather, it appears that certain characteristics of the cognitive event being examined determine the nature of the functional reorganization reported for a particular cognitive condition. In some cases, the recruitment of homotopic contralateral areas of the brain appears to be necessary to add the neural capacity to cope with the extra requirements AG-014699 clinical trial that a task is imposing on the aging brain. With reference to the phenomena described in the literature, this could be a combination of the HAROLD and CRUNCH phenomena. In other cases, it appears that the way in which the task is cognitively executed in the brain changes with aging. For example, the observations that semantic oral naming and visual attention are sustained in older individuals are compatible with the idea that these tasks are executed in a way that relies on enhanced abilities

(e.g. for semantic oral naming this would be semantic memory), skipping other less efficient processes (e.g. for semantic oral naming this would be frontostriatal-based executive processes). In some sense, the PASA phenomenon LY2109761 clinical trial captures the idea that some sort of cognitive compensation applies through the use of a different cognitive strategy. However, it also appears that the PASA phenomenon might be task-determined as the intrahemispheric shift in activation observed in functional brain imaging can be either posterior–anterior or anterior–posterior, probably depending on the nature of the compensatory mechanisms engaged. It is therefore clear that the brains of aging individuals who do not exhibit any change in cognitive abilities undergo important neurofunctional

reorganization in order to support such preserved performance. Nevertheless, we strongly believe that the exact nature of the neurofunctional reorganization does not follow mafosfamide a specific pattern. On the contrary, there seem to be many possible reorganization patterns, each of them determined by a number of factors including the nature of the task, the nature of the specific cognitive processes used to perform the task, the relative perceived increase in task complexity, and the use of a different cognitive strategy. The identification of these determinants and their specific roles should inspire future research in the cognitive neuroscience of optimal aging.

The ensuing fast rebound burst was due to T-type calcium current,

The ensuing fast rebound burst was due to T-type calcium current, as previously described. It was highly variable between cells in strength, and could

be expressed fully after short periods of hyperpolarization. In contrast, a subsequent prolonged rebound component required longer and deeper periods of hyperpolarization before it was fully established. We found using voltage-clamp and dynamic-clamp analyses that a slowly inactivating persistent sodium current fits the conductance underlying this prolonged rebound component, resulting in spike rate increases over several seconds. Overall, our results demonstrate that multiphasic DCN rebound properties could be elicited differentially by different levels of Purkinje cell activation, and thus create a rich repertoire of potential rebound dynamics in the cerebellar control of motor MS275 timing. “

colonise the brain parenchyma at early stages of development and accumulate in specific regions where they participate in cell death, angiogenesis, neurogenesis and synapse elimination. A recurring feature of embryonic microglial is their association with developing axon tracts, which, together with in vitro data, supports the idea of a physiological role for microglia Panobinostat datasheet in neurite development. Yet the demonstration of this role of microglia is lacking. Here, we have studied the consequences of microglial dysfunction on the formation of the corpus callosum, the largest commissure of the mammalian brain, which shows consistent microglial accumulation during development. We studied two models of microglial dysfunction: the loss-of-function of DAP12, a key microglial-specific signalling molecule, and a model of maternal inflammation by peritoneal injection of lipopolysaccharide at embryonic day (E)15.5. We also took advantage of the Pu.1−/− mouse line, which is devoid of microglia. We performed transcriptional profiling of maternally inflamed and Dap12-mutant microglia at E17.5. The two treatments principally down-regulated genes involved in nervous system development

and function, particularly in neurite formation. We then analysed the developmental consequences of these microglial dysfunctions on the formation of the corpus callosum. We Carbohydrate show that all three models of altered microglial activity resulted in the defasciculation of dorsal callosal axons. Our study demonstrates that microglia display a neurite-development-promoting function and are genuine actors of corpus callosum development. It further shows that microglial activation impinges on this function, thereby revealing that prenatal inflammation impairs neuronal development through a loss of trophic support. “
“Parkinson’s disease is characterized by a selective loss of dopaminergic neurons in the substantia nigra (SN). However, whether regenerative endogenous neurogenesis is taking place in the mammalian SN of parkinsonian and non-parkinsonian brains remains of debate.

, 1997; Trotter & Celebrini, 1999; Rosenbluth & Allman, 2002; Dur

, 1997; Trotter & Celebrini, 1999; Rosenbluth & Allman, 2002; Durand et al., 2010) and in the posterior parietal cortex (Andersen et al., 1985; Andersen, 1995; Xu et al., 2012) are modulated by gaze direction via gain control mechanisms (termed the

gain fields). However, modulation of neuronal responses by gaze-dependent EX 527 molecular weight gain fields cannot explain our results, because the spatiotopic learning effect completely transfers to untrained gaze directions as long as the trained stimulus relation remained unchanged (Zhang & Li, 2010). It has been proposed that the gain control mechanisms can be used to transform a retinotopic Tacrolimus cell line map into a spatiotopic one (Zipser & Andersen, 1988; Salinas & Thier, 2000; Pouget et al., 2002), whereby neuronal representation of a stimulus becomes independent of its retinal location. Neurons with such spatiotopic properties have been found in the parietal cortex (Galletti et al., 1993; Duhamel et al., 1997). Some imaging and psychophysical studies even suggest the presence of spatiotopic maps in visual cortical areas processing motion (Melcher & Morrone, 2003; d’Avossa et al., 2007; Crespi et al., 2011; Turi & Burr, 2012) and form (Melcher, 2005) information. However, several lines of evidence actually

argue for an absence, in the visual cortex, of any explicit spatiotopic representation that is independent of stimulus location on the retina (Gardner et al., 2008; Wenderoth & Wiese, 2008; Knapen et al., 2009, 2011; Morris et al., 2010; Ong & Bisley,

2011; Golomb & Kanwisher, 2012). Our finding that the learning-induced spatiotopic effect depended on the trained retinal location also argues against an explicit spatiotopic map for processing simple stimulus attributes. Instead, the retinotopic dependence of the spatiotopic learning effect and its orientation dependency suggest that the underlying spatiotopic processing is directly based on a retinotopic map; but how is this process accomplished? CYTH4 Considering that the first stimulus in our experiments was followed by a saccade, one might speculate that the spatiotopic learning effect and its retinotopic dependency might involve peri-saccadic updating of the visual representation of the first stimulus on a retinotopic map. Such a transient spatiotopic mechanism, which has been reported in the parietal (Duhamel et al., 1992; Merriam et al., 2003), frontal (Sommer & Wurtz, 2006) and even visual (Nakamura & Colby, 2002; Merriam et al., 2007) cortical areas, enables updating of a visual stimulus from one retinotopic location to another around saccadic eye movements.