Differences in automated analyzers for assessing the use of imprecise serum chloride concentrations as indirect predictors of serum bromide concentrations.
ABSTRACT Although bromide (Br) is used to treat intractable epilepsy, serum Br concentrations are not routinely analyzed. The present study measured serum Br(-) and Cl(-) concentrations in Br-treated epileptic patients, showing a significant correlation between Br(-) and imprecise Cl(-) concentrations, which suggested the use of a unique correlating equation for each diagnostic tool. Results indicated that imprecise Cl(-) concentrations are useful markers for measuring appropriate serum Br(-) levels in epileptic patients.
- SourceAvailable from: Andreas Burkhalter
Article: Area map of mouse visual cortex.[show abstract] [hide abstract]
ABSTRACT: It is controversial whether mouse extrastriate cortex has a "simple" organization in which lateral primary visual cortex (V1) is adjoined by a single area V2 or has a "complex" organization, in which lateral V1 is adjoined by multiple distinct areas, all of which share the vertical meridian with V1. Resolving this issue is important for understanding the evolution and development of cortical arealization. We have used triple pathway tracing combined with receptive field recordings to map azimuth and elevation in the same brain and have referenced these maps against callosal landmarks. We found that V1 projects to 15 cortical fields. At least nine of these contain maps with complete and orderly representations of the entire visual hemifield and therefore represent distinct areas. One of these, PM, adjoins V1 at the medial border. Five areas, P, LM, AL, RL, and A, adjoin V1 on the lateral border, but only LM shares the vertical meridian representation with V1. This suggests that LM is homologous to V2 and that the lateral extrastriate areas do not represent modules within a single area V2. Thus, mouse visual cortex is "simple" in the sense that lateral V1 is adjoined by a single V2-like area, LM, and "complex" in having a string of areas in lateral extrastriate cortex, which receive direct V1 input. The results suggest that large numbers of areas with topologically equivalent maps of the visual field emerge early in evolution and that homologous areas are inherited in different mammalian lineages.The Journal of Comparative Neurology 06/2007; 502(3):339-57. · 3.66 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Spatial attention influences representations in visual cortical areas as well as perception. Some models predict a contrast gain, whereas others a response or activity gain when attention is directed to a contrast-varying stimulus. Recent evidence has indicated that microstimulating the frontal eye field (FEF) can produce modulations of cortical area V4 neuronal firing rates that resemble spatial attention-like effects, and we have shown similar modulations of functional magnetic resonance imaging (fMRI) activity throughout the visual system. Here, we used fMRI in awake, fixating monkeys to first measure the response in 12 visual cortical areas to stimuli of varying luminance contrast. Next, we simultaneously microstimulated subregions of the FEF with movement fields that overlapped the stimulus locations and measured how microstimulation modulated these contrast response functions (CRFs) throughout visual cortex. In general, we found evidence for a nonproportional scaling of the CRF under these conditions, resembling a contrast gain effect. Representations of low-contrast stimuli were enhanced by stimulation of the FEF below the threshold needed to evoke saccades, whereas high-contrast stimuli were unaffected or in some areas even suppressed. Furthermore, we measured a characteristic spatial pattern of enhancement and suppression across the cortical surface, from which we propose a simple schematic of this contrast-dependent fMRI response.Journal of Neuroscience 09/2009; 29(34):10683-94. · 6.91 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The neocortex of the normal mouse has been subdivided into architectonic fields on the basis of its cellular and fiber patterns. The map of medial, retrohippocampal, frontal and insular regions is little different from that of Brodmann as modified in minor ways by Krieg. The map of parietal, occipital and temporal regions follows closely the major rearrangements introduced to Brodmann's map by Krieg. Krieg's map has been modified to give individual status to the barrel fields and to disignate occipital fields around the full circumference of field 17, and temporal fields circumferentially around field 41.The Journal of Comparative Neurology 12/1975; 164(2):247-63. · 3.66 Impact Factor