Analysis Of Activity Patterns Research Articles

Principal component analysis of odor coding at the level of third‐order olfactory neurons in Drosophila

Olfactory information in Drosophila is conveyed by projection neurons from olfactory sensory neurons to Kenyon cells (KCs) in the mushroom body (MB). A subset of KCs responds to a given odor molecule, and the combination of these KCs represents a part of the neuronal olfactory code. KCs are also thought to function as coincidence detectors for memory formation, associating odor information with a coincident punishment or reward stimulus. Associative conditioning has been shown to modify KC output. This plasticity occurs in the vertical lobes of MBs containing α/α' branches of KCs, which is shown by measuring the average Ca(2+) levels in the branch of each lobe. We devised a method to quantitatively describe the population activity patterns recorded from axons of >1000 KCs at the α/α' branches using two-photon Ca(2+) imaging. Principal component analysis of the population activity patterns clearly differentiated the responses to distinct odors.

활동패턴분석방법론의 개발과 적용 : 종합건강검진서비스 적용사례를 중심으로

본 연구는 정보시스템 기능 설계와 활동원가기준 예산, 그리고 IT 프로젝트 타당성을 확보하기 위해 개발된 활동패턴분석방법론을 소개하고, 2010년 종합건강검진센터에 적용한 사례를 통해 활동패턴분석의 유용성을 제시하였다. 활동패턴분석은 분석대상 범위 내 행위자들의 활동 분리, 활동 조정, 활동가치산출을 핵심 논리로 하며, 자원기반이론과 행위자 네트워크 이론을 중심 이론으로 한다. 본 연구에서 제시한 G검진센터는 활동패턴분석 진단을 통해 (1) IT 전략, (2) IT구축 목표, (3) 새로운 비즈니스 프로세스, (4) 정보시스템 설계도(기능 명세), (5) 정보시스템 구축 예산 및 타당성을 확보하였다. 활동패턴분석은 분석범위와 분석시기 결정이 유연하며, 분석대상을 분석목적에 적합하도록 확장할 수 있다는 점에서 유용하다. 궁극적으로는 정보시스템 도입 조직의 IS자원 관리능력의 내부화를 위한 방법론으로 활용될 수 있다. Activity Pattern Analysis(APA) is the methodology to Design the functions of information systems, to Estimate the monetary value of IS based on Activity Based Costing, to Acquire feasibility of IT Project. This study shows APA case in Health Check-up Service Organization (G-Center) and the Utility of APA. G-Center had acquired Five Outcomes through APA: (1) IT Strategy, (2) IT Project Goals, (3) Transformed Business Process, (4) Functional Blueprint of Information Systems, (5) IT Project budget and its feasibility. APA consists of three analysis processes; Activity Separation, Activity Rearrangement, Activity Costing. APA is flexible in determinating the range and the time of analysis, and is able to expand the Actors(as analysis objects) based on the purpose of analysis by researcher. Eventually APA can be used to do internal IT Management effectively.

Shared Representations for Working Memory and Mental Imagery in Early Visual Cortex

Early visual areas contain specific information about visual items maintained in working memory, suggesting a role for early visual cortex in more complex cognitive functions [1-4]. It is an open question, however, whether these areas also underlie the ability to internally generate images de novo (i.e., mental imagery). Research on mental imagery has to this point focused mostly on whether mental images activate early sensory areas, with mixed results [5-7]. Recent studies suggest that multivariate pattern analysis of neural activity patterns in visual regions can reveal content-specific representations during cognitive processes, even though overall activation levels are low [1-4]. Here, we used this approach [8, 9] to study item-specific activity patterns in early visual areas (V1-V3) when these items are internally generated. We could reliably decode stimulus identity from neural activity patterns in early visual cortex during both working memory and mental imagery. Crucially, these activity patterns resembled those evoked by bottom-up visual stimulation, suggesting that mental images are indeed "perception-like" in nature. These findings suggest that the visual cortex serves as a dynamic "blackboard" [10, 11] that is used during both bottom-up stimulus processing and top-down internal generation of mental content.

Integrating Circadian Activity and Gene Expression Profiles to Predict Chronotoxicity of Drosophila suzukii Response to Insecticides

Native to Southeast Asia, Drosophila suzukii (Matsumura) is a recent invader that infests intact ripe and ripening fruit, leading to significant crop losses in the U.S., Canada, and Europe. Since current D. suzukii management strategies rely heavily on insecticide usage and insecticide detoxification gene expression is under circadian regulation in the closely related Drosophila melanogaster, we set out to determine if integrative analysis of daily activity patterns and detoxification gene expression can predict chronotoxicity of D. suzukii to insecticides. Locomotor assays were performed under conditions that approximate a typical summer or winter day in Watsonville, California, where D. suzukii was first detected in North America. As expected, daily activity patterns of D. suzukii appeared quite different between ‘summer’ and ‘winter’ conditions due to differences in photoperiod and temperature. In the ‘summer’, D. suzukii assumed a more bimodal activity pattern, with maximum activity occurring at dawn and dusk. In the ‘winter’, activity was unimodal and restricted to the warmest part of the circadian cycle. Expression analysis of six detoxification genes and acute contact bioassays were performed at multiple circadian times, but only in conditions approximating Watsonville summer, the cropping season, when most insecticide applications occur. Five of the genes tested exhibited rhythmic expression, with the majority showing peak expression at dawn (ZT0, 6am). We observed significant differences in the chronotoxicity of D. suzukii towards malathion, with highest susceptibility at ZT0 (6am), corresponding to peak expression of cytochrome P450s that may be involved in bioactivation of malathion. High activity levels were not found to correlate with high insecticide susceptibility as initially hypothesized. Chronobiology and chronotoxicity of D. suzukii provide valuable insights for monitoring and control efforts, because insect activity as well as insecticide timing and efficacy are crucial considerations for pest management. However, field research is necessary for extrapolation to agricultural settings.

Abiotic environmental factors influencing blowfly colonisation patterns in the field

The accuracy of minimum post-mortem interval (mPMI) estimates usually hinges upon the ability of forensic entomologists to predict the conditions under which calliphorids will colonise bodies. However, there can be delays between death and colonisation due to poorly understood abiotic and biotic factors, hence the need for a mPMI. To quantify the importance of various meteorological and light-level factors, beef liver baits were placed in the field (Victoria, Australia) on 88 randomly selected days over 3 years in all seasons and observed every 60–90min for evidence of colonisation. Baits were exposed during daylight, and the following parameters were measured: barometric pressure, light intensity, wind speed, ambient temperature, relative humidity and rainfall. Collected data were analysed using backward LR logistic regression to produce an equation of colonisation probability. This type of analysis removes factors with the least influence on colonisation in successive steps until all remaining variables significantly increase the accuracy of predicting colonisation presence or absence. Ambient temperature was a positive predictor variable (an increase in temperature increased the probability of calliphorid colonisation). Relative humidity was a negative predictor variable (an increase in humidity decreased the probability of calliphorid colonisation). Barometric pressure, light intensity, wind speed and rainfall did not enhance the accuracy of the probability model; however, analysis of species activity patterns suggests that heavy rainfall and strong wind speeds inhibit calliphorid colonisation.

Sequential analysis of masseter activity patterns during chewing in healthy males

The present study examined sequential changes in masseter activity patterns observed during chewing of four different agar samples in eight healthy young males. Two parameters, T50 and D50, were specifically used for evaluation of the activity patterns of individual bursts. Statistical significances were detected in regression coefficients (21.9% of 32 trials) and Spearman’s rank correlation coefficients (28.1%) between the calculated T50 values and chewing cycles, whereas no significant differences among the four agar samples were found. Three (I–III) types of activity patterns of masseter bursts during chewing sequences were classified by the D50 values, which were derived from the T50 values. The three types physiologically corresponded to incrementing (Type I), decrementing (Type III) and mixed discharge patterns (Type II). The classification of activity patterns suggested the usefulness of D50 values in the sequential analysis of masseter activity patterns.

Analysis of Masseter Activity Patterns Using TP Values during Chewing of Foods with Different Shapes and Textural Properties

AbstractThe present study examined the ability of physiological parameters of chewing to discriminate between six foods of differing shapes and textural properties. Parameters were measured from masseter electromyograms, which were recorded from healthy and young subjects while they chewed the test foods. Analysis of conventional parameters showed that the number of chewing cycles dropped by 8.8 cycles upon a 100‐kPa increase in food fracturability and by 6.6 cycles upon a 5.0‐kJ/m3 increase in food adhesiveness. Analysis of the newly developed parameters showed that a 100‐kPa increase in food hardness increased the T25, T50 and T75 values by 0.015, 0.020 and 0.021 points, respectively, whereas a 100‐kPa increase in the food fracturability decreased the T25 and T50 values by 0.061 and 0.070 points, respectively. The results suggest that combining several physiological parameters will enhance discrimination between foods because individual parameters are sensitive to different food properties.Practical ApplicationsTogether with other measures, analyzing the activity of the masseter, a muscle responsible for closing the jaw, can provide objective information about food texture. The present study used electromyography to examine the quantitative relationships between various physiological parameters associated with masseter activity during chewing and the textural properties of food. The study focused on everyday foods rather than the model foods that are usually tested in laboratory studies. In addition to analyzing the textural properties (such as hardness and adhesiveness) using conventional physiological parameters, we also developed new parameters, TP values, to assess the masseter activity patterns specifically. The combined use of these physiological parameters is expected to aid clinicians and the food industry in their interactions with individuals who, owing to their age and sequelae of cerebrovascular diseases, have particular difficulty verbalizing their experience of chewing foods.

Silencing Mutant Ataxin-3 Rescues Motor Deficits and Neuropathology in Machado-Joseph Disease Transgenic Mice

Machado-Joseph disease (MJD) or spinocerebellar ataxia type 3 (SCA3) is an autosomal dominantly-inherited neurodegenerative disorder caused by the over-repetition of a CAG codon in the MJD1 gene. This expansion translates into a polyglutamine tract that confers a toxic gain-of-function to the mutant protein – ataxin-3, leading to neurodegeneration in specific brain regions, with particular severity in the cerebellum. No treatment able to modify the disease progression is available. However, gene silencing by RNA interference has shown promising results. Therefore, in this study we investigated whether lentiviral-mediated allele-specific silencing of the mutant ataxin-3 gene, after disease onset, would rescue the motor behavior deficits and neuropathological features in a severely impaired transgenic mouse model of MJD. For this purpose, we injected lentiviral vectors encoding allele-specific silencing-sequences (shAtx3) into the cerebellum of diseased transgenic mice expressing the targeted C-variant of mutant ataxin-3 present in 70% of MJD patients. This variation permits to discriminate between the wild-type and mutant forms, maintaining the normal function of the wild-type allele and silencing only the mutant form. Quantitative analysis of rotarod performance, footprint and activity patterns revealed significant and robust alleviation of gait, balance (average 3-fold increase of rotarod test time), locomotor and exploratory activity impairments in shAtx3-injected mice, as compared to control ones injected with shGFP. An important improvement of neuropathology was also observed, regarding the number of intranuclear inclusions, calbindin and DARPP-32 immunoreactivity, fluorojade B and Golgi staining and molecular and granular layers thickness. These data demonstrate for the first time the efficacy of gene silencing in blocking the MJD-associated motor-behavior and neuropathological abnormalities after the onset of the disease, supporting the use of this strategy for therapy of MJD.

Advanced Signal Processing Methods for Biomedical Imaging

Advanced Signal Processing Methods for Biomedical Imaging

Fear of the dark or dinner by moonlight? Reduced temporal partitioning among Africa's large carnivores

Africa is home to the last intact guild of large carnivores and thus provides the only opportunity to investigate mechanisms of coexistence among large predator species. Strong asymmetric dominance hierarchies typically characterize guilds of large carnivores; but despite this asymmetry, subdominant species may persist alongside their stronger counterparts through temporal partitioning of habitat and resources. In the African guild, the subdominant African wild dogs and cheetahs are routinely described as diurnal and crepuscular. These activity patterns have been interpreted to result from the need to avoid encounters with the stronger, nocturnal spotted hyenas and lions. However, the idea that diel activity patterns of carnivore species are strongly shaped by competition and predation has recently been challenged by new observations. In a three-year study in the Okavango Delta, we investigated daily activity patterns and temporal partitioning for wild dogs, cheetahs, spotted hyenas and lions by fitting radio collars that continuously recorded activity bursts, to a total of 25 individuals. Analysis of activity patterns throughout the 24-h cycle revealed an unexpectedly high degree of temporal overlap among the four species. This was mainly due to the extensive and previously undescribed nocturnal activity of wild dogs and cheetahs. Their nocturnal activity fluctuated with the lunar cycle, represented up to 40% of the diel activity budget and was primarily constrained by moonlight availability. In contrast, the nocturnal activity patterns of lions and hyenas were unaffected by moonlight and remained constant over the lunar cycle. Our results suggest that other ecological factors such as optimal hunting conditions have shaped the diel activity patterns of subdominant, large predators. We suggest that they are "starvation driven" and must exploit every opportunity to obtain a meal. The benefits of activity on moonlit nights therefore offset the risks of encountering night-active predators and competitors.

Eye shape and the nocturnal bottleneck of mammals

Most vertebrate groups exhibit eye shapes that vary predictably with activity pattern. Nocturnal vertebrates typically have large corneas relative to eye size as an adaptation for increased visual sensitivity. Conversely, diurnal vertebrates generally demonstrate smaller corneas relative to eye size as an adaptation for increased visual acuity. By contrast, several studies have concluded that many mammals exhibit typical nocturnal eye shapes, regardless of activity pattern. However, a recent study has argued that new statistical methods allow eye shape to accurately predict activity patterns of mammals, including cathemeral species (animals that are equally likely to be awake and active at any time of day or night). Here, we conduct a detailed analysis of eye shape and activity pattern in mammals, using a broad comparative sample of 266 species. We find that the eye shapes of cathemeral mammals completely overlap with nocturnal and diurnal species. Additionally, most diurnal and cathemeral mammals have eye shapes that are most similar to those of nocturnal birds and lizards. The only mammalian clade that diverges from this pattern is anthropoids, which have convergently evolved eye shapes similar to those of diurnal birds and lizards. Our results provide additional evidence for a nocturnal 'bottleneck' in the early evolution of crown mammals.

Wing morphology, echolocation, and resource partitioning in syntopic Cuban mormoopid bats

In this study we combine analyses of wing morphology, echolocation calls, and temporal and spatial activity patterns to explore mechanisms of ecological partitioning among 4 syntopic Antillean mormoopids (Pteronotus macleayii, P. parnellii, P. quadridens, and Mormoops blainvillei). We captured bats with mist nets and harp traps, and monitored bat activity using automated Anabat systems for 31 nights at Sierra del Rosario Biosphere Reserve in Cuba. The wing morphologies (very low wing-loading and average-aspect ratio) and echolocation calls (broadband steep frequency-modulated calls at high frequencies) of all 4 species suggest that Cuban mormoopids are adapted to slow maneuverable flight, adequate for hunting insects by slow aerial hawking in background-cluttered habitat. However, our data show that each species has a combination of wing and echolocation call characters, presumably reflecting differences in their foraging behavior and microhabitat use. All 4 species were present at the 3 sampling sites and a majority showed similar activity rates at each site. Thus, we did not find strong evidence of spatial segregation during foraging. However, overall activity levels were higher in the primary forest when compared with 2 secondary-growth forests. Most pair-wise comparisons of temporal activity patterns between species were significant, suggesting high levels of temporal segregation. Our data suggest that wing morphology, echolocation call structure, and temporal activity patterns are morphological and behavioral factors that could facilitate resource partitioning among the Cuban mormoopid bats.

Distinct contributions of the caudate nucleus, rostral prefrontal cortex, and parietal cortex to the execution of instructed tasks

When we behave according to rules and instructions, our brains interpret abstract representations of what to do and transform them into actual behavior. In order to investigate the neural mechanisms behind this process, we devised an fMRI experiment that explicitly isolated rule interpretation from rule encoding and execution. Our results showed that a specific network of regions (including the left rostral prefrontal cortex, the caudate nucleus, and the bilateral posterior parietal cortices) is responsible for translating rules into executable form. An analysis of activation patterns across conditions revealed that the posterior parietal cortices represent a mental template for the task to perform, that the inferior parietal gyrus and the caudate nucleus are responsible for instantiating the template in the proper context, and that the left rostral prefrontal cortex integrates information across complex relationships.

Modeling study of a Central Pattern Generator in the Melibe seaslug

Behaving animals show correlated neuronal activities in their nervous system. These observations lead to the question, how are the specific patterns of activities generated and used to control behaviors? Central Pattern Generators (CPGs) are small networks of neurons that are experimentally identified as necessary for expressions of behaviors, and the core group capable of controlling various aspects of the behavior. Mechanistic understanding of CPG functions is under intense investigation [1]. In this study, we investigate the role of network configurations of an experimentally based CPG for swimming behavior in the marine invertebrate Melibe leonine [2]. Repetitive nature of activity patterns of CPGs can be examined through the relative phase relations between bursting interneurons. Experimentally and computationally, such phase-lags are measured with respect to a reference neuron, thus allowing for an analysis of various activity patterns in a systematic way. For the Melibe CPG model under consideration, we consider four HodgkinHuxley type square-wave bursters, connected via fast nondelayed inhibitory synapses represented by fast threshold modulating function. Due to intrinsic symmetry, the network can be treated as two pairs of half center oscillators (HCOs). In a HCO both neurons reciprocally inhibit each other, leading to alternate, anti-phase bursting patterns, which can coexist with in-phase bursting when the HCO is inhibited externally [3,4]. In the given model, one HCO inhibits the other one and gets ap ositive feedback in the form of excitatory drive. We will further enhance the CPG model by including additional interneurons to reflect physiological fine details observed in-vitro. The exploration of stable phase-locked states, perturbed externally by applied current pulses, allows us to suggest plausible mechanisms of the CPG and come up with predictions that may be verified by electrophysiological experiments. The phase-locked pattern, observed in the experiment, is identified as an attractor in numerical simulations. We find that specific distributions of synaptic conductance shift the attractor so that it merges with a saddle corresponding to unstable phase-locked state. Investigation indicates that weak excitatory connections play no significant role in the generation of the pattern but may have stabilizing effect. Electrical coupling, which appears to be very weak and negligible in the physiological context, may play a critical role in altering the behavior of the network. Conclusions We conclude that the idiosyncratic phase-locking seen in the experimental setup is due to a specific network configuration of the CPG model where a driving HCO uni-directionally inhibits a nearly identical one, provided that coupling strengths stay rather weak. Future investigations will be focused on enhanced realistic CPG models with additional connections and participating interneurons.

Fluorescence analysis of the metabolic activity patterns of a neuronal–glial network

This paper shows that spontaneous network activity is present in a neuronal–glial network in the form of patterns that have the same character of the oscillations and synchronous switching of the generation regimes of all the patterns by recording the fluorescence of specific indicators for visualizing the dynamics of the calcium oscillations in cell cultures and culture sections of the hippocampus of the brain.

Fuzzy clustering of human activity patterns

In the context of human activity pattern analysis, we adopt a fuzzy clustering around medoids approach to classify ordered sequences (paths). These sequences represent patterns of individual behavior in an actual or virtual space–time domain. A fuzzy approach is suitable for path data, since sequences of human activities are typically characterized by switching behaviors, which are likely to produce overlapping clusters. We adopt a partitioning around medoids strategy since in human activity patterns analysis it is useful to represent each cluster by means of an observed (not fictitious) prototype (medoid). To measure pairwise distances among all sequence pairs we make use of the Levenshtein distance, which allows for the comparison between sequences of different length and explicitly takes into account the sequential nature of the data. We also consider two robust versions of the fuzzy clustering algorithm based, respectively, on the noise cluster and on the trimming technique. Robust algorithms deal with noisy observations, which are likely to occur in this framework and could provide an improvement to the standard model. We show several applications on sequence data, regarding different research areas, like Web usage mining, travel behavior, tourists and shopping paths.

Behavioural patterns of cattle in the communal areas of the Eastern Cape Province, South Africa

Incorporating knowledge of cattle activity or social behavior in rangeland management has the potential to improve both range condition and cattle productivity through intervention in and using the ongoing expression of behavior to detect veld condition changes. Currently, there is limited information on free ranging cattle activity patterns despite a concerted effort to introduce rotational grazing in communal rangelands. This grazing method interferes with livestock mobility, a necessity in heterogeneous semi-arid rangelands. It is, therefore, important that before evaluating rotational grazing intervention impacts in communal rangelands, an analysis of cattle activity patterns be done. Activity patterns of cattle in relation to forage quality, veld type, season, time of the day and management type were studied in a free-range grazing system in three villages in the Eastern Cape Province. Behaviour was determined by visually observing two animals during daylight hours for 2 days in each season. Current activity of each animal was recorded at 30 min fixed intervals until noon, and every 60 min thereafter. Percentage of the observation time spent in a particular activity for each observed animal were calculated for the duration of the observation. Seasonal activity patterns varied only at Upper Mnxe, with time spent grazing (77%), resting (35%) and walking (24%) higher in April, November and June respectively. Kraaling and mountain stockpost grazing management types affected the activity patterns of cattle, causing either an increase in morning grazing activity to cater for loss in grazing time or extensive walking in winter to compensate for forage scarcity. Rotational grazing can be introduced in mesic grasslands without adverse effects on animals, in contrast to semi-arid areas where major behavioural changes are needed as a coping strategy. Key words:

Spatial Representation of Odorant Valence in an Insect Brain

Brains have to decide whether and how to respond to detected stimuli based on complex sensory input. The vinegar fly Drosophila melanogaster evaluates food sources based on olfactory cues. Here, we performed a behavioral screen using the vinegar fly and established the innate valence of 110 odorants. Our analysis of neuronal activation patterns evoked by attractive and aversive odorants suggests that even though the identity of odorants is coded by the set of activated receptors, the main representation of odorant valence is formed at the output level of the antennal lobe. The topographic clustering within the antennal lobe of valence-specific output neurons resembles a corresponding domain in the olfactory bulb of mice. The basal anatomical structure of the olfactory circuit between insects and vertebrates is known to be similar; our study suggests that the representation of odorant valence is as well.

Cortical activation during the perception of intelligible and unintelligible speech as measured via high- density electroencephalography

High-density electroencephalography (EEG) was used to evaluate cortical activity patterns during the auditory processing of speech presented at various levels of degradation in a sentence verification task. 25 healthy participants listened to true-false sentences produced with one of 3 channel levels (1, 6, 16), ranging from unintelligible, moderately intelligible, and highly intelligible. Behavioral data were collected via button press (reaction time and accuracy) for each sentence. The analysis of cortical activation patterns includes 1) the identification of independent components that account for variations of activity associated with degradation levels and 2) the examination of associated event-related potentials. Statistical analyses will be performed on individuals' cortical activity, in tandem with behavioral data. Preliminary results reveal differences in the timing and magnitude of frontal and temporal lobe activation that coincide with task difficulty. Results of the present investigation will inform hypotheses about regions of interest for further investigation and will bear on models of connected speech perception, including the neurobiological underpinnings of individual differences and manifestations in a listener's understanding of degraded speech.

EMG analysis of lower limb muscle activation pattern during pedaling: Experiments and computer simulations

The purpose of this study was to investigate the performance of the recumbent bicycle. The recumbent bicycle is a type of bicycle usually used to train or exercise a patient or the elderly. A recumbent bicycle was specially constructed for this study by researchers. The speed and power can be recorded and displayed on the monitor of the recumbent bicycle. The experiments consisted of four steps with different start-knee angle (α=85°, 105°, 125°, 145°). The activation and force of lower limb muscles were measured and calculated using an electromyography (EMG) and a computer simulation respectively. The maximum of intraclass correlation coefficients (ICC) and their differences were calculated to compare between the data of different muscles. The data obtained from test and retest was shown to have a good reliability on all of the measured muscles. The ICC is 0.93 for biceps femoris (BF) of step 2 (α=105°). The maximum muscle activation and muscle force were also measured at step 2. The BF EMG of step 2 was shown to be significantly different (p<0.05) from other steps. Overall, the recumbent bicycle was shown to be similar in function with an upright bicycle. The frequency use of the recumbent bicycle is predicted to increase for a patient and the elderly due to stable seat structure which have bucket shape.