Temporal Response Patterns Research Articles

Dynamic transcriptional signatures and network responses for clinical symptoms in influenza-infected human subjects using systems biology approaches.

Recent studies demonstrate that human blood transcriptional signatures may be used to support diagnosis and clinical decisions for acute respiratory viral infections such as influenza. In this article, we propose to use a newly developed systems biology approach for time course gene expression data to identify significant dynamically response genes and dynamic gene network responses to viral infection. We illustrate the methodological pipeline by reanalyzing the time course gene expression data from a study with healthy human subjects challenged by live influenza virus. We observed clear differences in the number of significant dynamic response genes (DRGs) between the symptomatic and asymptomatic subjects and also identified DRG signatures for symptomatic subjects with influenza infection. The 505 common DRGs shared by the symptomatic subjects have high consistency with the signature genes for predicting viral infection identified in previous works. The temporal response patterns and network response features were carefully analyzed and investigated.

Inhibition does not affect the timing code for vocalizations in the mouse auditory midbrain.

Many animals use a diverse repertoire of complex acoustic signals to convey different types of information to other animals. The information in each vocalization therefore must be coded by neurons in the auditory system. One way in which the auditory system may discriminate among different vocalizations is by having highly selective neurons, where only one or two different vocalizations evoke a strong response from a single neuron. Another strategy is to have specific spike timing patterns for particular vocalizations such that each neural response can be matched to a specific vocalization. Both of these strategies seem to occur in the auditory midbrain of mice. The neural mechanisms underlying rate and time coding are unclear, however, it is likely that inhibition plays a role. Here, we examined whether inhibition is involved in shaping neural selectivity to vocalizations via rate and/or time coding in the mouse inferior colliculus (IC). We examined extracellular single unit responses to vocalizations before and after iontophoretically blocking GABAA and glycine receptors in the IC of awake mice. We then applied a number of neurometrics to examine the rate and timing information of individual neurons. We initially evaluated the neuronal responses using inspection of the raster plots, spike-counting measures of response rate and stimulus preference, and a measure of maximum available stimulus-response mutual information. Subsequently, we used two different event sequence distance measures, one based on vector space embedding, and one derived from the Victor/Purpura Dq metric, to direct hierarchical clustering of responses. In general, we found that the most salient feature of pharmacologically blocking inhibitory receptors in the IC was the lack of major effects on the functional properties of IC neurons. Blocking inhibition did increase response rate to vocalizations, as expected. However, it did not significantly affect spike timing, or stimulus selectivity of the studied neurons. We observed two main effects when inhibition was locally blocked: (1) Highly selective neurons maintained their selectivity and the information about the stimuli did not change, but response rate increased slightly. (2) Neurons that responded to multiple vocalizations in the control condition, also responded to the same stimuli in the test condition, with similar timing and pattern, but with a greater number of spikes. For some neurons the information rate generally increased, but the information per spike decreased. In many of these neurons, vocalizations that generated no responses in the control condition generated some response in the test condition. Overall, we found that inhibition in the IC does not play a substantial role in creating the distinguishable and reliable neuronal temporal spike patterns in response to different vocalizations.

Reduced endogenous estrogen and hemicastration interact synergistically to increase porcine sertoli cell proliferation.

Both reduced endogenous estrogen and hemicastration stimulate proliferation of porcine Sertoli cells. The objective of these experiments was to compare the temporal patterns of response to each stimulus with the response to the combined stimuli as indications of shared or separate mechanisms. Within a replicate, one littermate was treated weekly with canola oil vehicle and remained intact; a second littermate was treated weekly with vehicle, and one testis was removed at Day 8; a third littermate was treated weekly with the aromatase inhibitor letrozole to reduce endogenous estrogens and remained intact; and the fourth littermate was treated weekly with letrozole, and one testis was removed at Day 8. Four replicates were evaluated at 2 wk of age, five replicates evaluated at 6.5 wk of age, and five replicates were evaluated at 11 wk of age, with treatment ceasing at 6 wk of age. Numbers of Sertoli cells were determined following GATA4 labeling using the optical dissector method. Levels of estradiol, estrogen conjugates, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and inhibin were determined by radioimmunoassay. Hemicastration appeared to have a rapid effect on Sertoli cell proliferation, but letrozole treatment had no apparent effect on Sertoli cell numbers at 2 wk of age. Both letrozole treatment and hemicastration had stimulated Sertoli cell proliferation by 6.5 wk of age, although the magnitude of the hemicastration response was much greater. Letrozole appeared to have minimal interaction with hemicastration at this age. Letrozole and hemicastration together increased Sertoli cell numbers at 11 wk of age compared with either treatment alone. Estradiol and estrogen conjugates were dramatically reduced by aromatase inhibition as anticipated; treatment-induced changes in inhibin, LH, or FSH were minimal. Differences in timing of response and positive interaction at 11 wk of age suggest that hemicastration and letrozole stimulate proliferation of Sertoli cells by two initially different pathways.

Initial versus longer‐term effects of tadpole declines on algae in a Neotropical stream

Summary Information about temporal patterns of ecological responses to species losses is integral to our understanding of the ultimate effects of declining biodiversity. As part of the Tropical Amphibian Declines in Streams (TADS) project, we quantified changes in algal biomass and N cycling in algae in upland Panamanian streams following the widespread decline of larval anurans. Reach‐scale monitoring during and after a catastrophic, disease‐driven amphibian decline showed significant 2.8‐fold increases (P < 0.05) in algal biomass in pools and 6.3‐fold increases in riffles in the 5 months following the decline. 3 years after the decline, the magnitude of this initial change dampened to increases (P < 0.05) of 2‐fold in pools and 3.5‐fold in riffles over pre‐decline levels. Similarly, total organic matter of benthic biofilms, measured as ash‐free dry mass (AFDM), increased significantly by 2.2‐fold in pools and 2.3‐fold in riffles in the initial 5‐month post‐decline period, with the magnitude of these changes dampening slightly to a 2‐fold increase in pools and 1.9‐fold increase in riffles over pre‐decline levels after 3 years (P < 0.05 for differences at 5 months and 3 years). There were initial increases (P < 0.05) in Chl a:AFDM ratios 5 months after the decline, but ratios had returned to pre‐decline levels after 3 years. Algal food quality (as C/N) increased slightly, but not significantly, during the initial 5‐month post‐decline period and remained constant over 3 years. Mean δ15N in biofilms in pool habitat (measured over the reach scale) was significantly depleted initially following tadpole declines and remained significantly depleted 3 years after the decline (4.34 ‰ pre‐ versus 3.24‰ post‐; P < 0.05), suggesting that the loss of tadpoles reduced N recycling. Increases in abundance and production of some grazing macroinvertebrate taxa after the decline may have contributed to the gradual reduction in the difference between initial and longer‐term post‐decline algal biomass. However, algal biomass was still 2‐fold greater than pre‐decline levels after 3 years, indicating that grazing macroinvertebrates did not fully compensate for the loss of tadpoles.

A dynamic trajectory class model for intensive longitudinal categorical outcome.

This paper presents a novel dynamic latent class model for a longitudinal response that is frequently measured as in our prospective study of older adults with monthly data on activities of daily living for more than 10 years. The proposed method is especially useful when the longitudinal response is measured much more frequently than other relevant covariates. The trajectory classes are latent classes that represent distinct temporal patterns of the longitudinal response wherein an individual may remain in a trajectory class or switch to another as the class membership predictors are updated periodically over time. The identification of a common set of trajectory classes allows changes among the temporal patterns to be distinguished from local fluctuations in the response. Within a trajectory class, the longitudinal response is modeled by a class-specific generalized linear mixed model. An informative event such as death is jointly modeled by class-specific probability of the event through shared random effects with that for the longitudinal response. We do not impose the conditional independence assumption given the classes. We illustrate the method by analyzing the change over time in activities of daily living trajectory class among 754 older adults with 70,500 person-months of follow-up in the Precipitating Events Project. We also investigate the impact of jointly modeling the class-specific probability of the event on the parameter estimates in a simulation study. The primary contribution of our paper is the periodic updating of trajectory classes for a longitudinal categorical response without assuming conditional independence.

Quantitative analysis of neuronal response properties in primary and higher-order auditory cortical fields of awake house mice (Mus musculus).

Because of its great genetic potential, the mouse (Mus musculus) has become a popular model species for studies on hearing and sound processing along the auditory pathways. Here, we present the first comparative study on the representation of neuronal response parameters to tones in primary and higher-order auditory cortical fields of awake mice. We quantified 12 neuronal properties of tone processing in order to estimate similarities and differences of function between the fields, and to discuss how far auditory cortex (AC) function in the mouse is comparable to that in awake monkeys and cats. Extracellular recordings were made from 1400 small clusters of neurons from cortical layers III/IV in the primary fields AI (primary auditory field) and AAF (anterior auditory field), and the higher-order fields AII (second auditory field) and DP (dorsoposterior field). Field specificity was shown with regard to spontaneous activity, correlation between spontaneous and evoked activity, tone response latency, sharpness of frequency tuning, temporal response patterns (occurrence of phasic responses, phasic-tonic responses, tonic responses, and off-responses), and degree of variation between the characteristic frequency (CF) and the best frequency (BF) (CF–BF relationship). Field similarities were noted as significant correlations between CFs and BFs, V-shaped frequency tuning curves, similar minimum response thresholds and non-monotonic rate-level functions in approximately two-thirds of the neurons. Comparative and quantitative analyses showed that the measured response characteristics were, to various degrees, susceptible to influences of anesthetics. Therefore, studies of neuronal responses in the awake AC are important in order to establish adequate relationships between neuronal data and auditory perception and acoustic response behavior.

Characteristics of Patients on Antiretroviral Therapy With Prolonged Virological Failure

Characteristics of Patients on Antiretroviral Therapy With Prolonged Virological Failure

Increased tyrosine hydroxylase expression accompanied by glial changes within the non-lesioned hemisphere in the 6-hydroxydopamine model of Parkinson's disease

Parkinson's disease (PD) is characterized by striatal synaptic deafferentation followed by dopaminergic cell death in the substantia nigra pars compacta. Not only degenerative, but also regenerative, compensatory changes at distant sites of the primary lesion may occur in PD. The aim of the study was to analyze the temporal pattern of axonal and glial responses over a time course of six weeks post-lesioning. For this aim, 6-hydroxydopamine (6-OHDA) was injected unilaterally into the medial forebrain bundle and both lesioned and non-lesioned striata were analyzed. We detected increased tyrosine hydroxylase (TH) immunoreactivity within the non-lesioned striatum six weeks after injection indicative either of increased TH expression or compensatory neuritic changes. An increased number of microglial cells was present in both lesioned and unlesioned striata. There was no obvious change in microglial phenotype or in pro-inflammatory cytokine gene expression within the striatum without any apparent switch into a pro-inflammatory phenotype. No changes were observed in the number of mature oligodendrocytes. This temporal pattern shows, that the non-lesioned striatum undergoes profound changes, involving increased TH expression accompanied by a glial response. A better understanding of this complex interplay of neuronal as well as glial components not only within the lesioned, but also non-lesioned striatum may help to restore local neural circuits in PD.

Area-dependent time courses of brain activation during video-induced symptom provocation in social anxiety disorder.

BackgroundPrevious functional imaging studies using symptom provocation in patients with social anxiety disorder (SAD) reported inconsistent findings, which might be at least partially related to different time-dependent activation profiles in different brain areas. In the present functional magnetic resonance imaging study, we used a novel video-based symptom provocation design in order to investigate the magnitude and time course of activation in different brain areas in 20 SAD patients and 20 healthy controls.ResultsThe disorder-related videos induced increased anxiety in patients with SAD as compared to healthy controls. Analyses of brain activation to disorder-related versus neutral video clips revealed amygdala activation during the first but not during the second half of the clips in patients as compared to controls. In contrast, the activation in the insula showed a reversed pattern with increased activation during the second but not during the first half of the video clips. Furthermore, a cluster in the anterior dorsal anterior cingulate cortex showed a sustained response for the entire duration of the videos.ConclusionsThe present findings suggest that different regions of the fear network show differential temporal response patterns during video-induced symptom provocation in SAD. While the amygdala is involved during initial threat processing, the insula seems to be more involved during subsequent anxiety responses. In accordance with cognitive models of SAD, a medial prefrontal region engaged in emotional-cognitive interactions is generally hyperactivated.

Functional transformations of odor inputs in the mouse olfactory bulb.

Sensory inputs from the nasal epithelium to the olfactory bulb (OB) are organized as a discrete map in the glomerular layer (GL). This map is then modulated by distinct types of local neurons and transmitted to higher brain areas via mitral and tufted cells. Little is known about the functional organization of the circuits downstream of glomeruli. We used in vivo two-photon calcium imaging for large scale functional mapping of distinct neuronal populations in the mouse OB, at single cell resolution. Specifically, we imaged odor responses of mitral cells (MCs), tufted cells (TCs) and glomerular interneurons (GL-INs). Mitral cells population activity was heterogeneous and only mildly correlated with the olfactory receptor neuron (ORN) inputs, supporting the view that discrete input maps undergo significant transformations at the output level of the OB. In contrast, population activity profiles of TCs were dense, and highly correlated with the odor inputs in both space and time. Glomerular interneurons were also highly correlated with the ORN inputs, but showed higher activation thresholds suggesting that these neurons are driven by strongly activated glomeruli. Temporally, upon persistent odor exposure, TCs quickly adapted. In contrast, both MCs and GL-INs showed diverse temporal response patterns, suggesting that GL-INs could contribute to the transformations MCs undergo at slow time scales. Our data suggest that sensory odor maps are transformed by TCs and MCs in different ways forming two distinct and parallel information streams.

Cannabinoid Receptor Activation Shifts Temporally Engendered Patterns of Dopamine Release

The ability to discern temporally pertinent environmental events is essential for the generation of adaptive behavior in conventional tasks, and our overall survival. Cannabinoids are thought to disrupt temporally controlled behaviors by interfering with dedicated brain timing networks. Cannabinoids also increase dopamine release within the mesolimbic system, a neural pathway generally implicated in timing behavior. Timing can be assessed using fixed-interval (FI) schedules, which reinforce behavior on the basis of time. To date, it remains unknown how cannabinoids modulate dopamine release when responding under FI conditions, and for that matter, how subsecond dopamine release is related to time in these tasks. In the present study, we hypothesized that cannabinoids would accelerate timing behavior in an FI task while concurrently augmenting a temporally relevant pattern of dopamine release. To assess this possibility, we measured subsecond dopamine concentrations in the nucleus accumbens while mice responded for food under the influence of the cannabinoid agonist WIN 55,212-2 in an FI task. Our data reveal that accumbal dopamine concentrations decrease proportionally to interval duration--suggesting that dopamine encodes time in FI tasks. We further demonstrate that WIN 55,212-2 dose-dependently increases dopamine release and accelerates a temporal behavioral response pattern in a CB1 receptor-dependent manner--suggesting that cannabinoid receptor activation modifies timing behavior, in part, by augmenting time-engendered patterns of dopamine release. Additional investigation uncovered a specific role for endogenous cannabinoid tone in timing behavior, as elevations in 2-arachidonoylglycerol, but not anandamide, significantly accelerated the temporal response pattern in a manner akin to WIN 55,212-2.

Timing vocal behaviour: Experimental evidence for song overlap avoidance in Eurasian wrens

Timing during vocal interactions can play a significant role in terms of audibility as signal overlap may lead to masking of acoustic details for both of the interacting animals as well as for third-party eavesdroppers. Here we investigated timing aspects experimentally in Eurasian wrens (Troglodytes troglodytes) using non-interactive playback. We applied a randomized overlay method incorporating the temporal pattern of singing by the focal bird to establish a null model and to test observed patterns of overlap against this null model. We used different stimulus song rates but temporal response patterns always resulted in significantly lower levels of overlap than expected by chance. The male wrens avoided overlapping by timing their song starts predominately right after the end of stimulus songs, but they did not avoid being overlapped by the stimulus songs. The territorial males typically raised their song rates during and after playback with a tendency to shorten between-song intervals while keeping song durations unchanged. Higher song rates of the playback stimuli increased the extent to which responders were being overlapped by the stimulus songs. Our data provide experimental evidence for a timing ability in Eurasian wrens by which they reduce mutual interference during vocal interactions.

The Growth Factor Receptor ERBB2 Regulates Mitochondrial Activity on a Signaling Time Scale

Overexpression of the ERBB2 receptor tyrosine kinase and the mitochondrial inner membrane protein UCP2 occurs frequently in aggressive cancers with dysfunctional mitochondria. Overexpressed ERBB2 signals constitutively and elevated UCP2 can uncouple mitochondria and alleviate oxidative stress. However, the physiological contributions of UCP2 and ERBB2 at the low expression levels that are typical of most tissues, as well as the path to oncogenic deregulation, are poorly understood. We now show that ERBB2 directly controls UCP2 levels, both at low physiological levels and oncogenic overexpression. At low levels of receptor and UCP2, ligand stimulation creates a distinct temporal response pattern driven by the opposing forces of translational suppression of the exceptionally short lived UCP2 protein and a time delayed transcriptional up-regulation. The latter becomes dominant through constitutive signaling by overexpressed ERBB2, resulting in high levels of UCP2 that contribute mitochondrial uncoupling. By contrast, ligand stimulation of non-overexpressed ERBB2 transiently removes UCP2 and paradoxically reduces the mitochondrial membrane potential, oxygen consumption, and OXPHOS on a signaling time scale. However, neither the transporter activity nor down-regulation of already low UCP2 levels drive this reduction in mitochondrial activity. Instead, UCP2 is required to establish mitochondria that are capable of responding to ligand. UCP2 knockdown impairs proliferation at high glucose but its absence specifically impairs ligand-induced growth when glucose levels fluctuate. These findings demonstrate the ability of growth factor signaling to control oxidative phosphorylation on a signaling time scale and point toward a non-transporter role for low levels of UCP2 in establishing dynamic response capability.

Degradation of chemical alarm cues and assessment of risk throughout the day

The use of chemical information in assessment of predation risk is pervasive across animal taxa. However, by its very nature, chemical information can be temporally unreliable. Chemical cues persist for some period of time after they are released into the environment. Yet, we know surprisingly little about the rate of degradation of chemical cues under natural conditions and hence little about how they function in temporal risk assessment under natural conditions. Here, we conducted an experiment to identify a concentration of fresh alarm cues that evoke a strong antipredator response in coral reef damselfish, Pomacentrus ambonensis. We then tested the rate at which these alarm cues degraded under natural conditions in ocean water, paying attention to whether the rate of degradation varied throughout the day and whether the temporal pattern correlated with physicochemical factors that could influence the rate of degradation. Fresh alarm cues released into ocean water evoke strong avoidance responses in juvenile fish, while those aged for 30 min no longer evoke antipredator responses. Fish exposed to cues aged for 10 or 20 min show intermediate avoidance responses. We found a marked temporal pattern of response throughout the day, with much faster degradation in early to mid-afternoon, the time of day when solar radiation, temperature, dissolved oxygen, and pH are nearing their peak. Ecologists have spent considerable effort elucidating the role of chemical information in mediating predator–prey interactions, yet we know almost nothing about the temporal dynamics of risk assessment using chemical information. We are in dire need of additional comparative field experiments on the rate of breakdown of chemical cues, particularly given that global change in UV radiation, temperature, and water chemistry could be altering the rates of degradation and the potential use of this information in risk assessment.

Assessing Color Bias in the Popularity of TV Comedies and Dramas, 1964-1994: Time-Series Analyses of 30 Years of Nielsen Ratings in the USA

The initial motivating question of this study asks if the racial composition of the regular casts of television comedies and dramas broadcast on the major networks in the USA during the years from 1964 to 1994 made any difference in the shows' life spans. Did longevity vary by the cast's color (C status) -- that is, by the presence of zero, one, a few, or a majority of regular cast members who were recognizably Black? The follow-up question, contingent on evidence of a longevity difference, was of the process resulting in that difference: since the C status of a show was for all practical purposes constant throughout its life span, causal agency would have been expressed through some variable process sensitive to that condition, a likely candidate being audience response as measured by a show's rating or share from week to week.Using the individual time function of each of 98 TV shows -- all 47 that qualified as Black, plus a sample of 51 non-Black, with no left or right-hand censoring of observations of ratings and shares -- we estimate parameters of trend and limit-cycle process models of the ratings and shares time functions. There was indeed a longevity difference by C status. It varied in sign, depending on proportion of regular cast who were Black. Shows with a minority of regular cast members who were Black had a small advantage relative to shows with no Black cast members, probably due to gains of Black viewers that more than offset any losses of non-Black viewers. But there was a tipping point, beyond which the balance of attractions reversed, resulting in shorter longevities of shows that were too Black.There was some evidence that the process by which the C-status difference was expressed did include, or at least was correlated with, audience response as measured by ratings and shares. The evidence is manifest mainly in the fact that the C-status difference in longevity was much reduced, once variations estimates of model parameters of the shows' time functions are taken into account. Attempts to allocate that reduction across specific parameters were not successful, however. The longevity difference by C status was maintained, if very weakly, independently of the temporal patterns of audience response.

Effect of ECAP-Based Choice of Stimulation Rate on Speech-Perception Performance

The objective determination of an optimal stimulation rate for CI users could save time and take the uncertainty out of choosing a rate based on patient preference. Electrically evoked compound action potential (ECAP) temporal response patterns vary across stimulation rates and cochlear regions, and could be useful in objectively predicting an optimal rate. Given that only one rate of stimulation can be used for current CI devices, we propose two potential ways to investigate whether a rate that produces stochastic ECAP responses (termed stochastic rate) can be used to predict an optimal stimulation rate. The first approach follows that of , which compared performance across three cochlear regions using limited electrode sets. This approach, which has inherent limitations, may provide insight into the effects of region-specific stochastic rates on performance. The second, more direct, approach is to compare speech perception for full-array maps that each uses a stochastic rate from a different region of the cochlea. Using both of these methods in a set of two acute experiments, the goal of the present study was to assess the effects of stochastic rate on speech perception. Speech-perception stimuli included the Hearing in Noise Test (HINT sentences), Consonant-Nucleus-Consonant (CNC) phonemes, and Iowa Medial Consonants. For Experiment 1, 22 ears in 20 CI recipients were tested in three map conditions (basal-only, middle-only, and apical-only electrode sets) using the subject's daily-use stimulation rate to first explore the level of performance possible with region-specific maps. A one-way repeated-measures analysis of variance (RM ANOVA) was used to examine the effect of electrode region on performance. A subset of nine subjects was tested with three additional maps (basal-only, middle-only, and apical-only electrode sets) using the region-specific stochastic rate, as measured in a previous study. A two-way RM ANOVA was used to assess the effects of electrode region and per-channel stimulation rate on performance for this subgroup. For Experiment 2, the same subset of nine subjects was tested with four full-array maps that each used either the daily-use stimulation rate or one of the stochastic rates. A one-way RM ANOVA was used to examine the effect of stimulation rate on performance. For Experiment 1, average performance with the daily-use rate and the stochastic rate was significantly better using the middle electrode set for HINT sentences and CNC phonemes. Perception of medial consonants was similar using the basal and middle electrode sets, and both of these were better than consonant perception with the apical region. For the subgroup of subjects tested with both the daily and stochastic rates, results revealed that stimulation rate did not have a significant effect on performance. For Experiment 2, results revealed no significant differences in performance using full-array maps with different stochastic rates or with the daily-use rate. Speech-perception scores were higher using the middle electrode set than with the basal or apical sets; however, this may have resulted from less spectral compression for the middle-region map. The effect of using stochastic rate as an optimal stimulation rate requires further investigation. A longer acclimatization period may be more likely to show differences in performance using stochastic rates versus daily-use rates.

Frontotemporal oxyhemoglobin dynamics predict performance accuracy of dance simulation gameplay: Temporal characteristics of top-down and bottom-up cortical activities

We utilized the high temporal resolution of functional near-infrared spectroscopy to explore how sensory input (visual and rhythmic auditory cues) are processed in the cortical areas of multimodal integration to achieve coordinated motor output during unrestricted dance simulation gameplay. Using an open source clone of the dance simulation video game, Dance Dance Revolution, two cortical regions of interest were selected for study, the middle temporal gyrus (MTG) and the frontopolar cortex (FPC). We hypothesized that activity in the FPC would indicate top-down regulatory mechanisms of motor behavior; while that in the MTG would be sustained due to bottom-up integration of visual and auditory cues throughout the task. We also hypothesized that a correlation would exist between behavioral performance and the temporal patterns of the hemodynamic responses in these regions of interest. Results indicated that greater temporal accuracy of dance steps positively correlated with persistent activation of the MTG and with cumulative suppression of the FPC. When auditory cues were eliminated from the simulation, modifications in cortical responses were found depending on the gameplay performance. In the MTG, high-performance players showed an increase but low-performance players displayed a decrease in cumulative amount of the oxygenated hemoglobin response in the no music condition compared to that in the music condition. In the FPC, high-performance players showed relatively small variance in the activity regardless of the presence of auditory cues, while low-performance players showed larger differences in the activity between the no music and music conditions. These results suggest that the MTG plays an important role in the successful integration of visual and rhythmic cues and the FPC may work as top-down control to compensate for insufficient integrative ability of visual and rhythmic cues in the MTG. The relative relationships between these cortical areas indicated high- to low-performance levels when performing cued motor tasks. We propose that changes in these relationships can be monitored to gauge performance increases in motor learning and rehabilitation programs.

The Neuronal Responses to Repetitive Acoustic Pulses in Different Fields of the Auditory Cortex of Awake Rats

Cortical representation of time-varying features of acoustic signals is a fundamental issue of acoustic processing remaining unresolved. The rat is a widely used animal model for auditory cortical processing. Though some electrophysiological studies have investigated the neural responses to temporal repetitive sounds in the auditory cortex (AC) of rats, most of them were conducted under anesthetized condition. Recently, it has been shown that anesthesia could significantly alter the temporal patterns of neural response. For this reason, we systematically examined the single-unit neural responses to click-trains in the core region of rat AC under awake condition. Consistent with the reports on anesthetized rats, we confirmed the existence of characteristic tonotopic organizations, which were used to divide the AC into anterior auditory field (AAF), primary auditory cortex (A1) and posterior auditory field (PAF). We further found that the neuron's capability to synchronize to the temporal repetitive stimuli progressively decreased along the anterior-to-posterior direction of AC. The median of maximum synchronization rate was 64, 32 and 16 Hz in AAF, A1 and PAF, respectively. On the other hand, the percentage of neurons, which showed non-synchronized responses and could represent the stimulus repetition rate by the mean firing rate, increased from 7% in AAF and A1 to 20% in PAF. These results suggest that the temporal resolution of acoustic processing gradually increases from the anterior to posterior part of AC, and thus there may be a hierarchical stream along this direction of rat AC.

산지사면의 실측토양수분을 이용한 전이함수 모형의 적용

In this paper, time series of soil moisture were measured for a steep forest hillslope to model and understand distinct hydrological behaviours along two different transects. The transfer function analysis was presented to characterize temporal response patterns of soil moisture for rainfall events. The rainfall is a main driver of soil moisture variation, and its stochastic characteristic was properly treated prior to the transfer function delineation between rainfall and soil moisture measurements. Using field measurements for two transects during the rainy season in 2007 obtained from the Bumrunsa hillslope located in the Sulmachun watershed, a systematic transfer functional modeling was performed to configure the relationships between rainfall and soil moisture responses. The analysis indicated the spatial variation pattern of hillslope hydrological processes, which can be explained by the relative contribution of vertical, lateral and return flows and the impact of transect topography.

Application of regularised optimal fingerprinting to attribution. Part II: application to global near-surface temperature

Attribution of global near-surface temperature changes is revisited using simulations from the coupled model intercomparison project 5 and methodological improvements from the regularised optimal fingerprinting approach. The analysis of global mean temperature shows that changes can be robustly detected and attributed to anthropogenic influence. However, the differences between results from individual models and observations are found to be larger than the simulated internal variability in sev- eral cases. Discrimination between greenhouse gases and other anthropogenic forcings, based on the global mean only, is more difficult due to collinearity of temporal response patterns. Using spatio-temporal data provides less robust conclusions with respect to detection and attribution, as the results tend to deteriorate as the spatial resolution increases. More importantly, some inconsistencies between individual models and observations are found in this case. Such behaviour is not observed in a perfect model frame- work, where pseudo-observations and the expected response patterns are provided by the same model. How- ever, using response patterns from a model other than the one used for pseudo-observations may lead to the same behaviour as real observations. Our results suggest that additional sources of uncertainty, such as modeling uncertainty or observational uncertainty, should not be neglected in detection and attribution.