Spike Type Research Articles

Raise of short-stemmed vaviloid branched spike lines and their cytogenetics

Hybridization between hexaploid species of wheat ( Triticum L.) and triticale (Ч Triticosecale Wittm.) is used widely in genetic research and breeding when studying mutual introgressions of genetic material to original species. As far as the hexaploid triticale obtained in our Institute possessed a strong potential of morphogenesis, we decided to use it in crosses with bread wheat. During the process of morphogenesis in hybrid population of the second and third generations derived from the crosses between hexaploid triticale with different bread wheat cultivars (Opal and Chinese Spring) and variety (Triticum aestivum var. velutinum), plants with wheat, rye, intermediate, and triticale-like spike types were noted. Starting from the third generation, constant short-stemmed vaviloid branched spike plants were isolated among populations under study. Despite instability and numerous meiotic aberrations observed in the first generation of plants, including branched-spike ones, the subsequent progeny demonstrated meiotic and morphological stability. The chromosome composition of one of the lines (378/3SD) was characterized by fluorescence in situ hybridization (FISH) and genome in situ hybridization (GISH), and it was identified as a substitution line. Chromosomal identification of such lines will allow their use in genetic studies concerning specified traits, in particular, the vaviloid branched spike.

Magnetoencephalography using gradient magnetic field topography (GMFT) can predict successful anterior corpus callosotomy in patients with drop attacks

ObjectiveGradient magnetic field topography (GMFT) with magnetoencephalography (MEG) has been developed to demonstrate magnetic-field gradients of epileptic spikes on a volume-rendered brain surface. We evaluated GMFT in patients with anterior 2/3 corpus callosotomy (ACC) for drop-attacks. MethodsEight patients (age; 11–37years) underwent ACC. GMFT evaluated the predominant distributions (anterior/posterior) and the spreading patterns (unilateral/bilateral) of pre- and postoperative interictal MEG spikes corresponding to generalized spikes on EEG. We compared the occurrence of four types of spikes; anterior unilateral spike (AUS), posterior unilateral spike (PUS), anterior bilateral spike (ABS), posterior bilateral spike (PBS) between 5 patients (group G) with good control of drop attacks and 3 patients (group P) with residual drop attacks. ResultsPreoperatively, GMFT showed the proportion of ABS in group G (mean±SD, 57.4±9.7%) was significantly (p=0.024) higher than that in group P (31.6±15.2%). The number and proportion of postoperative ABS and PBS in group G were significantly decreased (p<0.05 in all). ConclusionGMFT is valuable to evaluate pre- and post-operative predominant spikes in patients with drop attacks. SignificanceGMFT revealed a higher proportion of preoperative ABS and postoperative decline of both ABS and PBS in patients with good control of drop attacks after ACC.

Evaluation of Bread Wheat (&lt;i&gt;Triticum aestivum&lt;/i&gt; L.) Breeding Lines for Yield and Yield Related Characters in Horo Guduru Wollega Zone, Western Ethiopia

A total of thirty-six bread wheat ( Triticum aestivum L.) breeding lines were evaluated for yield and yield related traits at high and midland environments of Horo Guduru Wollega Zone, western Ethiopia during 2013 cropping season. The genotypes were grown in a 6 x 6 simple lattice design. Data were collected for 12 morpho-agronomic characters. Since heterogeneity of variance test due to location was significant for most of traits, separate analyses for ANOVA, correlation and principal components were done. The differences between two means for significances were tested using SNK. The results of ANOVA showed that significant differences were observed among the breeding lines at both locations for DH, PH, SPL, SPS, BY, GY and TKW; while for DM and GFP at Gitilo and for HI at Guduru. At both locations, genotypes which showed superior performances compared to the standard checks 'Danada' and 'Kubsa' for biomass yield, grain yield, thousand kernel weight and harvest index include: ETBW7238, ETBW7235, ETBW7220, ETBW7191, ETBW7199, ETBW7182, ETBW7204, ETBW7258, ETBW7264, ETBW7247; and these genotypes are selected for multi adaptations. Principal components analysis showed that the first four PCs contributed about 81.06 % of the total phenotypic variation in the genotypes at Gitilo; while the f contributed about 77.01 % to the total phenotypic variations in the genotypes at Guduru. Analysis for traits association showed that at Gitilo, GY had strong and positive associations with SPL and BY, indicating that genotypes with long spike types. Similarly, at Guduru, GY was significantly and positively correlated with SPS, BY and HI. At both locations, traits which showed strong associations with GY could be used for indirect selection criteria during genotypes evaluation for better adaptabilities to the environment

Comparison of Dynamic Changes of Endogenous Plant Hormones and Hormone-Related Gene Expression between Near Isogenic Lines with Normal Spike and Branched Spike Wheat

Branched spike wheat is a hexaploid wheat with branched rachis on its main rachis, and branched rachises in the shoot apex occur and develop just after the two ridges stage. In this study, dynamic changes of four endogenous plant hormones [indole-3-acetic acid (IAA), gibberellic acid (GA), abscisic acid (ABA) and zeatin riboside (ZR)] and the expression of a hormone-related gene were measured among wheat lines with different genotypes and spike morphologies. It is a basis for further exploring the developmental mechanisms of branched spike and for breeding new wheat lines with more spikelets and grains. A group of near isogenic lines (NILs), including one branched spike line, and three normal spike type lines was sampled at four time points from the end of two ridges stage to the floret differentiation stage. The endogenous hormones in young shoots, young leaves and tillering nodes in these lines were measured and the expressions of TaIAR3, encoding IAA amide hydrolase which involvs in the IAA synthesis was detected. The results showed that the contents of IAA exhibited a significant different pattern in branched spike line from those in normal spike lines, while the contents of GA, ABA and ZR showed similar change patterns. The expressions of TaIAR3 were also significantly different between branched spike line and normal spike lines. Both the IAA content and TaIAR3 expression in branched spike wheat were much higher than those in the normal spike lines. These results suggest that quantitative changes in auxin may correspond to different spike morphology. Higher IAA content and TaIAR3 expression might be benefical for promoting the formation and elongation of branched rachis in branched spike wheat line.

Explaining Dopamine Deficiency of Spiking Neurons Based on Quantum Superposition Theory

In all mammalian brain billions of neurons exist and these neurons are working together through synapses and spike responses. Through numerous models presented to describe neuronal response and how the membrane potential would vary due to different tasks, still a big question stand still in the field of neuroscience. Why a neuron can produce different types of spikes under same conditions? Here we build up a new model of spiking neuron based on Izhikevich model which can generate all possible neuronal spikes and we try to answer this question by putting the concept of quantum superposition into account. We showed that unknown and random behavior of neuronal spikes through time can be described by this quantum fact that a neuron can be in many states at a same time, therefore any spike patterns or combination of spike patterns is of interest. Based on neuronal spikes patterns, sometimes we observed an unknown pattern can be explained by this phenomena that a neuron can exist partially in a physical state but when it’s response to an stimuli is recorded the result would be only one of the possible states or a linear combination of some states.

Registration of #STRKR Barley Germplasm

#STRKR (Reg. No. GP-208, PI 674325) is a hulless, six-row barley (Hordeum vulgare L.) germplasm composed of the bulk of three full-sib lines, two of which have winter growth habit and one of which has facultative growth habit. The germplasm was released by the Oregon Agricultural Experiment Station in 2014. The three sister lines from the Oregon State University Barley Breeding Program that were bulked to form #STRKR were derived from the cross of F1(‘Maja’/‘Legacy’)/Maja/3/‘Doyce’. #STRKR was tested under the experimental designation Streaker. The #STRKR germplasm is uniform for spike type, rachilla hair length, resistance to stripe rust (incited by by Puccinia striiformis f. sp. hordei), and grain quality parameters. It is relatively uniform in terms of height and heading date. #STRKR is phenotypically heterogeneous for awn texture, grain color, and tolerance to scald (incited by Rhynchosporium commune). As a blend, #STRKR has shown winter survival comparable to Maja in environments where there was differential winter injury. #STRKR germplasm provides a resource for reselection and a parental source for disease resistance and quality parameters.

Colocalization of allatotropin and tachykinin-related peptides with classical transmitters in physiologically distinct subtypes of olfactory local interneurons in the cockroach (Periplaneta americana).

In the insect antennal lobe different types of local interneurons mediate complex excitatory and inhibitory interactions between the glomerular pathways to structure the spatiotemporal representation of odors. Mass spectrometric and immunohistochemical studies have shown that in local interneurons classical neurotransmitters are likely to colocalize with a variety of substances that can potentially act as cotransmitters or neuromodulators. In the antennal lobe of the cockroach Periplaneta americana, gamma-aminobutyric acid (GABA) has been identified as the potential inhibitory transmitter of spiking type I local interneurons, whereas acetylcholine is most likely the excitatory transmitter of nonspiking type IIa1 local interneurons. This study used whole-cell patch clamp recordings combined with single-cell labeling and immunohistochemistry to test if the GABAergic type I local interneurons and the cholinergic type IIa1 local interneurons express allatotropin and tachykinin-related neuropeptides (TKRPs). These are two of the most abundant types of peptides in the insect antennal lobe. GABA-like and choline acetyltransferase (ChAT)-like immunoreactivity were used as markers for GABAergic and cholinergic neurons, respectively. About 50% of the GABA-like immunoreactive (-lir) spiking type I local interneurons were allatotropin-lir, and ∼ 40% of these neurons were TKRP-lir. About 20% of nonspiking ChAT-lir type IIa1 local interneurons were TKRP-lir. Our results suggest that in subpopulations of GABAergic and cholinergic local interneurons, allatotropin and TKRPs might act as cotransmitters or neuromodulators. To unequivocally assign neurotransmitters, cotransmitters, and neuromodulators to identified classes of antennal lobe neurons is an important step to deepen our understanding of information processing in the insect olfactory system.

Differentiated Doping Profile for Vertical Terahertz GaN Transferred-Electron Devices

The potential of vertical differentiated gallium nitride (GaN) transferred electron devices (TEDs) is compared with that of the base flat doping profile TED for the realization of RF power sources at 1 THz. The TED oscillator modeling is a time-domain continuous wave pure sine model. The semiconductor device model is a 1-D numerical physical macroscopic model based on the energy-momentum approach. Differentiated structures of notch, detached notch, and P <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> spike (PS) types have been optimized. By contrast with millimeter-wave differentiated TEDs operating in the dipole domain mode, the terahertz TED RF operating mode remains the accumulation layer/transit time mode. Comparison point out that the differentiated doping profile TEDs slightly improve both the TED RF performance and electronic limitation but above all improve the thermal limitation resulting from the high dc bias conditions due to high threshold electric field in GaN. Thus, the PS TED distinguishes itself as the most promising structure.

A neural network model of reliably optimized spike transmission.

We studied the detailed structure of a neuronal network model in which the spontaneous spike activity is correctly optimized to match the experimental data and discuss the reliability of the optimized spike transmission. Two stochastic properties of the spontaneous activity were calculated: the spike-count rate and synchrony size. The synchrony size, expected to be an important factor for optimization of spike transmission in the network, represents a percentage of observed coactive neurons within a time bin, whose probability approximately follows a power-law. We systematically investigated how these stochastic properties could matched to those calculated from the experimental data in terms of the log-normally distributed synaptic weights between excitatory and inhibitory neurons and synaptic background activity induced by the input current noise in the network model. To ensure reliably optimized spike transmission, the synchrony size as well as spike-count rate were simultaneously optimized. This required changeably balanced log-normal distributions of synaptic weights between excitatory and inhibitory neurons and appropriately amplified synaptic background activity. Our results suggested that the inhibitory neurons with a hub-like structure driven by intensive feedback from excitatory neurons were a key factor in the simultaneous optimization of the spike-count rate and synchrony size, regardless of different spiking types between excitatory and inhibitory neurons.

Spatiotemporal conditional inference and hypothesis tests for neural ensemble spiking precision.

The collective dynamics of neural ensembles create complex spike patterns with many spatial and temporal scales. Understanding the statistical structure of these patterns can help resolve fundamental questions about neural computation and neural dynamics. Spatiotemporal conditional inference (STCI) is introduced here as a semiparametric statistical framework for investigating the nature of precise spiking patterns from collections of neurons that is robust to arbitrarily complex and nonstationary coarse spiking dynamics. The main idea is to focus statistical modeling and inference not on the full distribution of the data, but rather on families of conditional distributions of precise spiking given different types of coarse spiking. The framework is then used to develop families of hypothesis tests for probing the spatiotemporal precision of spiking patterns. Relationships among different conditional distributions are used to improve multiple hypothesis-testing adjustments and design novel Monte Carlo spike resampling algorithms. Of special note are algorithms that can locally jitter spike times while still preserving the instantaneous peristimulus time histogram or the instantaneous total spike count from a group of recorded neurons. The framework can also be used to test whether first-order maximum entropy models with possibly random and time-varying parameters can account for observed patterns of spiking. STCI provides a detailed example of the generic principle of conditional inference, which may be applicable to other areas of neurostatistical analysis.

Spike train SIMilarity Space (SSIMS): a framework for single neuron and ensemble data analysis.

Increased emphasis on circuit level activity in the brain makes it necessary to have methods to visualize and evaluate large-scale ensemble activity beyond that revealed by raster-histograms or pairwise correlations. We present a method to evaluate the relative similarity of neural spiking patterns by combining spike train distance metrics with dimensionality reduction. Spike train distance metrics provide an estimate of similarity between activity patterns at multiple temporal resolutions. Vectors of pair-wise distances are used to represent the intrinsic relationships between multiple activity patterns at the level of single units or neuronal ensembles. Dimensionality reduction is then used to project the data into concise representations suitable for clustering analysis as well as exploratory visualization. Algorithm performance and robustness are evaluated using multielectrode ensemble activity data recorded in behaving primates. We demonstrate how spike train SIMilarity space (SSIMS) analysis captures the relationship between goal directions for an eight-directional reaching task and successfully segregates grasp types in a 3D grasping task in the absence of kinematic information. The algorithm enables exploration of virtually any type of neural spiking (time series) data, providing similarity-based clustering of neural activity states with minimal assumptions about potential information encoding models.

Bazı Arpa (Hordeum vulgare L.) Genotiplerinin Edirne Koşullarında

This research was carried out to determine of yield and some agronomic characters of some barley genotypes which was developed by Trakya Agricultural Research Institute and Bulgaria Karnobat Research Institute. The experiments were set up with 25 barley genotypes in completely randomized blocks design with four replications during 2006-2007 and 2007-2008 growing years in the experimental field of Trakya Agricultural Research Institute. The characters such as grain yield, plant height, spike length, heading and maturating days and grain number per spike and correlation among these traits were investigated. The results of the study showed that there were significant differences among the genotypes based on investigated characters. The mean grain yield of the genotypes was 647,4 kg/da. The highest grain yield (764,9 kg/da) was computed in TEA1500-22 line. In Trakya region, earliness is very important to production second crops in one growing season. The early heading genotype was TEA1525-25 line, while DRT136 was the latest heading line. Plant height is another important traits especially for lodging resistance in barley, and plant height ranged between 91,8 cm and 101,4 cm in the genotypes. The shortest plant height was measured in Veslets, TEA1535-21 and Sladoran. The spike length ranged between 6,8 cm and 9,9 cm in genotypes. Grain number per spike was 57,8 in the genotypes with 6 rows and, 27,7 grain in genotypes with 2 rows. The significant and negative correlation coefficient was determined between grain yield with spike length (r=-0,563) and days of heading (r=-0,718) in genotypes which has two rows spike type. The significant and positive correlation was determined between grain yield grain and grain number per spike (r=0,740). It was found that genotypes with early maturing gave higher grain yield than the others.

The effects of cultivar and nitrogen management on wheat yield and nitrogen use efficiency in the North China Plain

Understanding the inherent characteristics of cultivars with different spike types based on biomass and biomass partitioning with optimal nitrogen (N) management is important to achieve both high wheat yield and N use efficiency (NUE). A field experiment was conducted over 3 years using five N rates and two winter wheat cultivars (a larger spike cultivar (TN) and a multiple spike cultivar (LX)) in the North China Plain (NCP) to evaluate whether larger spike cultivar can accumulate more post-anthesis biomass and achieve higher yields and to determine the optimal N management strategies for the two cultivars. In both cultivars over 3 years, the optimal N rate (ONR) based on in-season root zone N management (INM) reduced the N rate by 140kgNha−1 from 300 to 160kgNha−1 without any yield losses, while it increased the N uptake efficiency from 32% to 64% compared with typical farmer's N practice (FNP). Furthermore, under ONR treatment, the grain yield and N physiological efficiency of TN significantly was higher 6 and 10% over 3 years than that of the multiple spike cultivar LX, respectively. The yield increase of TN was attributed mainly to the increased harvest index (7%) and similar total biomass. The higher 11% leaf N concentration at anthesis and 10% grain number m−2 of TN significantly increased the post-anthesis biomass by 24% under ONR, which played an important role in increasing the harvest index (HI). In addition, the grain yield of 70% ONR significantly decreased by 12% and 8% for TN and LX over 3 years, respectively, while no significant increase in grain yield was observed for 130% ONR, suggesting that the ONR was optimal in practice. Changes in N management may not be required for the two cultivars, because the ONR according to INM is close to the economically optimal N rate (EONR) based on grain yield response curves. In conclusion, selecting a larger spike cultivar with optimal N management could be a useful strategy to achieve high yield and high NUE for wheat production in the NCP, especially using optimal crop management practices.

MISFET-based biosensing interface for neurons guided growth and neuronal electrical activities recording

A hybrid circuit of a transistor-based chip was implemented and characterized for the neuronal electrical activity recording. The integration of microfluidic architectures was developed to control precisely neurites outgrowth and form topologically defined and stable neural networks. Individual neural cells from rat retinae and Lymnaea stagnalis snails were immobilized on gates regions of Metal Insulator Semiconductor Field Effect Transistors (MISFET). Neuronal orientation was achieved in both cases but neuronal action potentials were only recorded in the L. stagnalis case. They were successfully triggered and inhibited by implementing a picrotoxin – GABA – picrotoxin injection protocol, exhibiting a direct influence of picrotoxin on the “spike type” action potential waveform. The implementation of the whole process of neuronal culture and subsequent activity monitoring constitutes a proof-of-principle experiment for the development of neuroelectronic systems for signal processing studies adapted to low-density neuronal cultures.

Characterizing Emulsions by Observation of Single Droplet Collisions—Attoliter Electrochemical Reactors

We report an electrochemical study of the collisions of single droplets in an emulsion by two methods. In the first method, an electroactive redox species, for example, ferrocene, inside a toluene-in-water emulsion droplet (but not in the continuous phase) is measured by chronoamperometry during a collision with an ultramicroelectrode (UME). Here, a blip or spike type of collision signal is observed, representing electrolysis of the droplet contents. In the second method, electrochemical oxidation of an electroactive redox species in the continuous aqueous phase is hindered by a droplet blocking collision. In this case, a staircase current decrease is observed. From an analysis of single soft particle collision data, one can find the emulsion droplet size distribution and the droplet contents.

Simultaneous subdural and scalpEEGcorrelates of frontal lobe epileptic sources

To assess the visibility and detectability in scalp electroencephalography (EEG) of cortical sources in frontal lobe epilepsy (FLE) as to their localization, and the extent and amplitude of activation. We analyzed the simultaneous subdural and scalp interictal EEG recordings of 14 patients with refractory frontal lobe epilepsy (FLE) associated with focal cortical dysplasia. Subdural spike types were identified and averaged for source localization and detection of their scalp EEG correlates. Both raw and averaged scalp EEG segments were reviewed for spikes, blinded to subdural segments. We further analyzed the correlation of spike-to-background amplitude ratios in subdural and scalp EEG. We identified 36 spike types in subdural EEG, corresponding to 29 distinct sources. Four of 29 sources were visible by visual evaluation of scalp EEG and six additional sources were detectable after averaging: four in the medial frontal, two in the dorsolateral gyri, two in the depth of dorsolateral sulci, and two in the basal frontal region. Cortical sources generating scalp-detectable spikes presented a median of 6cm(2) of activated cortical convexity surface and a subdural spike-to-background-amplitude ratio >8. These sources were associated with a higher number of activated subdural grid contacts and a higher subdural spike-to-background amplitude ratio than sources generating non-scalp-detectable spikes. Not only dorsolateral but also basal and medial sources can be detectable in FLE. This is the first in vivo demonstration derived from simultaneous subdural and scalp EEG recordings of the complementary significance of extensive source activation and higher subdural spike-to-background amplitude ratio in the detection of cortical sources in FLE.

Comparison of Three Algorithms for Detection of Amperometric Spikes Resulting from Quantal Exocytosis

Electrochemical microelectrodes located immediately adjacent to the cell surface can detect spikes of amperometric current during quantal exocytosis as the transmitter released from a single vesicle is oxidized on the electrode surface. Automated techniques are needed to detect spikes that vary considerably in amplitude and time course. We compared three algorithms for spike detection against the gold standard of manual detection. The most widely used method for spike detection is testing when the current slope (first derivative) exceeds a threshold (DT method). The DT method is sensitive to the selection of both the low-pass filter settings and the threshold. A second method is to scan the data set with one or more prototype spike templates while performing a least-squares fit to find the amplitude and standard error of the fit at each time point. A spike is identified when the ratio of the fit amplitude to the standard error exceeds a threshold (CB method). This method is not as sensitive to filter settings or threshold but is sensitive to the choice of template(s). Finally, we tested a new approach (DLS method) that is similar to the CB method but performs a least-square fit of the sum of two templates consisting of faster and slower exponential decays. Receiver Operator Characteristic plots demonstrate that the DT method fails to detect slower spikes without generating significant false positives. The CB method also fails to detect some spikes manually identified when using up to three templates. On the other hand, the DLS method detected a much wider range of spike types with the use of only two spike templates. We conclude that the DLS method enables detection of a large variety of spikes without excessive computational cost. Supported by NIH R43MH96650.

An Efficient Method for Epileptic Seizure Detection in Long-Term EEG Recordings

Epilepsy is one of the most prevalent neurological disorders with no age, racial, social class, and neither national nor geographic boundaries. There are 50 million sufferers in the world today with 2.4 million new cases occur each year. Electroencephalogram (EEG) has become a traditional procedure to investigate abnormal functioning of brain activity. Epileptic EEG is usually characterized by short transients and sharp waves as spikes. Identification of such event splays a crucial role in epilepsy diagnosis and treatment. The present study proposes a method to detect three epileptic spike types in EEG recordings based mainly on Template Matching Algorithm including multiple signal-processing approaches. The method was applied to real clinical EEG data of epileptic patients and evaluated according to sensitivity, specificity, selectivity and average detection rate. The promising results illuminate that hybrid processing approaches in temporal, frequency and spatial domains can be a real solution to identify fast EEG transients.

Analysis of Noise and Non-Linearity of I-V Characteristics of Positive Temperature Coefficient Chip Thermistors

Abstract Noise spectroscopy and I-V characteristic non-linearity measurement were applied as diagnostic tools in order to characterize the volume and contact quality of positive temperature coefficient (PTC) chip sensors and to predict possible contact failure. Correctly made and stable contacts are crucial for proper sensing. I-V characteristics and time dependences of resistance were measured for studied sensors and, besides the samples with stable resistance value, spike type resistance fluctuation was observed for some samples. These spikes often disappear after about 24 hours of voltage application. Linear I-V characteristics were measured for the samples with stable resistance. The resistance fluctuation of burst noise type was observed for some samples showing the I-V characteristic dependent on the electric field orientation. We have found that the thermistors with high quality contacts had a linear I-V characteristic, the noise spectral density is of 1/f type and the third harmonic index is lower than 60 dB. The samples with poor quality contacts show non-linear I-V characteristics and excess noise is given by superposition of g-r and 1/fn type noises, and the third harmonic index is higher than 60 dB.

Fast fMRI provides high statistical power in the analysis of epileptic networks

EEG-fMRI is a unique method to combine the high temporal resolution of EEG with the high spatial resolution of MRI to study generators of intrinsic brain signals such as sleep grapho-elements or epileptic spikes. While the standard EPI sequence in fMRI experiments has a temporal resolution of around 2.5–3s a newly established fast fMRI sequence called MREG (Magnetic-Resonance-Encephalography) provides a temporal resolution of around 100ms. This technical novelty promises to improve statistics, facilitate correction of physiological artifacts and improve the understanding of epileptic networks in fMRI. The present study compares simultaneous EEG-EPI and EEG-MREG analyzing epileptic spikes to determine the yield of fast MRI in the analysis of intrinsic brain signals.Patients with frequent interictal spikes (>3/20min) underwent EEG-MREG and EEG-EPI (3T, 20min each, voxel size 3×3×3mm, EPI TR=2.61s, MREG TR=0.1s). Timings of the spikes were used in an event-related analysis to generate activation maps of t-statistics. (FMRISTAT, |t|>3.5, cluster size: 7 voxels, p<0.05 corrected). For both sequences, the amplitude and location of significant BOLD activations were compared with the spike topography.13 patients were recorded and 33 different spike types could be analyzed. Peak T-values were significantly higher in MREG than in EPI (p<0.0001). Positive BOLD effects correlating with the spike topography were found in 8/29 spike types using the EPI and in 22/33 spikes types using the MREG sequence. Negative BOLD responses in the default mode network could be observed in 3/29 spike types with the EPI and in 19/33 with the MREG sequence. With the latter method, BOLD changes were observed even when few spikes occurred during the investigation.Simultaneous EEG-MREG thus is possible with good EEG quality and shows higher sensitivity in regard to the localization of spike-related BOLD responses than EEG-EPI. The development of new methods of analysis for this sequence such as modeling of physiological noise, temporal analysis of the BOLD signal and defining appropriate thresholds is required to fully profit from its high temporal resolution.