Role In Temporal Processing Research Articles

Life in the fast lane: the role of temporal processing in risk-taking behaviors

An existing theoretical framework proposes that aberrant temporal processing and a fast internal clock, denoted by overestimation and under-reproduction of time, increases the likelihood of engagement in risky behaviors (ERB). The primary aim of this project was to improve our understanding of the relationship between temporal processing and ERB in college students. The present study used the Wittmann and Paulus (2008) theoretical framework to examine the associations between temporal processing and ERB in college students. College student participants (N = 215) completed self-report measures of ERB, delay aversion, inhibitory control, ADHD symptoms and objective cognitive time estimation and time reproduction tasks. Time estimation accuracy was significantly associated with lower engagement in sexual risk behaviors (OR = .988; 95% CI: .979, .996; p = .006) and aggressive behaviors (OR = .989; 95% CI: .980, .998; p = .018). Time reproduction was not significantly associated with ERB. The present study established preliminary support for the associations between aberrant temporal processing, namely aberrant time estimation, and ERB among college students.

Multisensory representations of space and time in sensory cortices.

Clear evidence demonstrated a supramodal organization of sensory cortices with multisensory processing occurring even at early stages of information encoding. Within this context, early recruitment of sensory areas is necessary for the development of fine domain-specific (i.e., spatial or temporal) skills regardless of the sensory modality involved, with auditory areas playing a crucial role in temporal processing and visual areas in spatial processing. Given the domain-specificity and the multisensory nature of sensory areas, in this study, we hypothesized that preferential domains of representation (i.e., space and time) of visual and auditory cortices are also evident in the early processing of multisensory information. Thus, we measured the event-related potential (ERP) responses of 16 participants while performing multisensory spatial and temporal bisection tasks. Audiovisual stimuli occurred at three different spatial positions and time lags and participants had to evaluate whether the second stimulus was spatially (spatial bisection task) or temporally (temporal bisection task) farther from the first or third audiovisual stimulus. As predicted, the second audiovisual stimulus of both spatial and temporal bisection tasks elicited an early ERP response (time window 50-90 ms) in visual and auditory regions. However, this early ERP component was more substantial in the occipital areas during the spatial bisection task, and in the temporal regions during the temporal bisection task. Overall, these results confirmed the domain specificity of visual and auditory cortices and revealed that this aspect selectively modulates also the cortical activity in response to multisensory stimuli.

Inactivation of Cerebellar Cortical Crus II Disrupts Temporal Processing of Absolute Timing but not Relative Timing in Voluntary Movements.

Several recent studies have demonstrated that the cerebellum plays an important role in temporal processing at the scale of milliseconds. However, it is not clear whether intrinsic cerebellar function involves the temporal processing of discrete or continuous events. Temporal processing during discrete events functions by counting absolute time like a stopwatch, while during continuous events it measures events at intervals. During the temporal processing of continuous events, animals might respond to rhythmic timing of sequential responses rather than to the absolute durations of intervals. Here, we tested the contribution of the cerebellar cortex to temporal processing of absolute and relative timings in voluntary movements. We injected muscimol and baclofen to a part of the cerebellar cortex of rats. We then tested the accuracy of their absolute or relative timing prediction using two timing tasks requiring almost identical reaching movements. Inactivation of the cerebellar cortex disrupted accurate temporal prediction in the absolute timing task. The rats formed two groups based on the changes to their timing accuracy following one of two distinct patterns which can be described as longer or shorter declines in the accuracy of learned intervals. However, a part of the cerebellar cortical inactivation did not affect the rats’ performance of relative timing tasks. We concluded that a part of the cerebellar cortex, Crus II, contributes to the accurate temporal prediction of absolute timing and that the entire cerebellar cortex may be unnecessary in cases in which accurately knowing the absolute duration of an interval is not required for temporal prediction.

Gender-specific effects of emotional modulation on visual temporal order thresholds.

Emotions affect temporal information processing in the low-frequency time window of a few seconds, but little is known about their effect in the high-frequency domain of some tens of milliseconds. The present study aims to investigate whether negative and positive emotional states influence the ability to discriminate the temporal order of visual stimuli, and whether gender plays a role in temporal processing. Due to the hemispheric lateralization of emotion, a hemispheric asymmetry between the left and the right visual field might be expected. Using a block design, subjects were primed with neutral, negative and positive emotional pictures before performing temporal order judgment tasks. Results showed that male subjects exhibited similarly reduced order thresholds under negative and positive emotional states, while female subjects demonstrated increased threshold under positive emotional state and reduced threshold under negative emotional state. Besides, emotions influenced female subjects more intensely than male subjects, and no hemispheric lateralization was observed. These observations indicate an influence of emotional states on temporal order processing of visual stimuli, and they suggest a gender difference, which is possibly associated with a different emotional stability.

The Effect of Auditory Training by the Use of Dichotic Tasks in the Role of Temporal Processing

Introduction: Usually, the principal focus during the individual auditory training is on hearing disabilities. An important aspect is to provide challenges for speech recognition in dichotic tasks and determine if this training improves other skills that were not trained before.

Contributions of the Basal Ganglia to Temporal Processing: Evidence from Parkinson’s Disease

The motor and perceptual timing deficits documented in patients with Parkinson’s disease (PD) have heavily influenced the theory that the basal ganglia play an important role in temporal processing. This review is a systematic exploration of the findings from behavioural and neuroimaging studies of motor and perceptual timing in PD. In particular, we consider the influence of a variety of task factors and of patient heterogeneity in explaining the mixed results. We also consider the effect of basal ganglia dysfunction on the non-temporal cognitive factors that contribute to successful motor and perceptual timing. Although there is convincing evidence from PD that the basal ganglia are critical to motor and perceptual timing, further work is needed to characterize the precise contribution of this complex structure to temporal processing.

Deciphering the impact of cerebellar and basal ganglia dysfunction in accuracy and variability of motor timing

Studies in motor timing have shown that the basal ganglia and cerebellum play an important role in temporal processing. Timing studies in Cerebellar/ataxic Disorders (CD) and Parkinson’s disease (PD) patients contrast the roles of the cerebellum and basal ganglia in motor timing. Here, we used a synchronization–continuation task to compare accuracy and variability of motor timing during repetitive tapping. We compared data collected for the present study – from patients with CD and healthy controls – to data from a previous study with patients with PD. We asked participants to tap at Inter-stimulus Intervals (ISIs) of 250, 500, 1000, and 2000ms. Using Linear Mixed Models (LMMs), we explored how ISI, Task Phase, and Diagnosis interacted to determine the (i) the accuracy and (ii) the variability of tapping. In our analysis of accuracy, we found evidence that during the synchronization phase, at ISI=250ms, CD patients lagged ‘behind the beat’; whereas our previous work has suggested that medicated PD patients hasten ‘ahead of the beat’. In our analysis of variability, we observed that at ISIs below 1000ms, CD patients showed greater variability in motor timing than the healthy controls, while PD patients showed less variability than CD patients and healthy controls during the synchronization phase at the 1000ms ISI. These results highlight the differential performance on explicit motor timing between patients with disorders of the cerebellum and basal ganglia. Our results illustrate a novel approach to discerning cognitive control of motor timing.

Dynamic Spike Thresholds during Synaptic Integration Preserve and Enhance Temporal Response Properties in the Avian Cochlear Nucleus

Neurons of the cochlear nuclei are anatomically and physiologically specialized to optimally encode temporal and spectral information about sound stimuli, in part for binaural auditory processing. The avian cochlear nucleus magnocellularis (NM) integrates excitatory eighth nerve inputs and depolarizing GABAergic inhibition such that temporal fidelity is enhanced across the synapse. The biophysical mechanisms of this depolarizing inhibition, and its role in temporal processing, are not fully understood. We used whole-cell electrophysiology and computational modeling to examine how subthreshold excitatory inputs are integrated and how depolarizing IPSPs affect spike thresholds and synaptic integration by chick NM neurons. We found that both depolarizing inhibition and subthreshold excitatory inputs cause voltage threshold accommodation, nonlinear temporal summation, and shunting. Inhibition caused such large changes in threshold that subthreshold excitatory inputs were followed by a refractory period. We hypothesize that these large shifts in threshold eliminate spikes to asynchronous inputs, providing a mechanism for the enhanced temporal fidelity seen across the eighth nerve/cochlear nucleus synapse. Thus, depolarizing inhibition and threshold shifting hone the temporal response properties of this system so as to enhance the temporal fidelity that is essential for auditory perception.

Spatial filter by spike timing dependent plasticity

Spike timing dependent plasticity (STDP) is found in various areas of the brain, visual cortex, hippocampus and hindbrain of electric fish, etc. The synaptic modification by STDP depends on time difference between presynaptic spike arrival and postsynaptic firing. If presynaptic neuron fires earlier than postsynaptic neuron dose, synaptic weight is strengthened. If postsynaptic neuron fires earlier than presynaptic neuron dose, synaptic weight is weakened. This learning rule is one example of various rules (hippocampal type). The learning rule of electric fish type is reversed. Changes of synaptic efficiency precisely depend on timing of pre- and postsynaptic spikes under STDP. Because of this precise dependence, STDP is thought to play the important role in temporal processing of stimuli. Temporal processing by STDP is well known. However, the role of STDP in spatial processing is not enough understood. To investigate spatial processing by STDP, We studied the role in spatial processing on interconnected network with STDP, using computer simulation. In this study, we found two type spatial filter by STDP on interconnected network. One is low pass filter using the learning rule of electric fish type. Another is edge-enhancing filter using the learning rule of hippocampus type. In this study, we calculated the response of interconnected neural network with STDP learning. The structure of the network is one-dimensional array. The neuron of the network has connection to neighbour neurons. In the case of learning rule of electric fish type, the network provided the function of low pass filter. The network was stimulated by direct current rectangularly distributed with noise. We examined two cases. In one case, synaptic modification did not occur (Fig ​(Fig1a).1a). In another case, synaptic modification occurred (Fig ​(Fig1b).1b). In the first case, Noise presented in response of the network and covered the rectangular form of stimulus. In the second case, noise was eliminated and the rectangular form of stimulus was represented. In the case of learning rule of hippocampal type, the network provided the function of edge-enhancing filter. The network was stimulated by direct current rectangularly distributed. The firing rate of the neuron that represents the edge of stimulus was larger than one of the others. This result shows that the network with hipocampal type STDP plays the role of edge-enhancing filter. These results show that interconnected network with STDP provides the function of spatial filter, and suggest that STDP would plays the important role in spatial processing. Figure 1 Response of network. Vertical and horizontal line indicates response of the network and neuronal number, respectively. (a) and (b) show the response of the network without and with STDP learning, respectively.

Subclinical sensory abnormalities in unaffected PINK1 heterozygotes

Mutations in the PINK1 gene, encoding a mitochondrial protein kinase, represent the second cause of autosomal recessive parkinsonism (ARP) after Parkin. While homozygous or compound heterozygous mutations in these genes are unequivocally causative of ARP, the role of single heterozygous mutations is still largely debated. An intriguing hypothesis suggests that these mutations could represent a risk factor to develop parkinsonism, by contributing to nigral cell degeneration. Since the substantia nigra plays an important role in temporal processing of sensory stimuli, as revealed from studies in idiopathic PD, we sought to investigate whether any subclinical sensory abnormalities could be detected in patients with PINK1- related parkinsonism and in unaffected PINK1 heterozygous carriers. We adopted a psychophysical method, the temporal discrimination paradigm, to assess PINK1 homozygous patients, unaffected relatives who were heterozygous carriers of the same mutations and healthy control subjects. Temporal discrimination threshold (TDT) and temporal order judgement (TOJ) for pairs of tactile, visual or visuo-tactile stimuli were measured according to a standardized protocol. Higher mean tactile and visuo-tactile TDTs and TOJs were detected in PINK1 mutation carriers, including not only homozygous patients but also healthy heterozygotes, compared to control subjects (for all comparisons, p < 0.001). In clinically unaffected subjects, the mere presence of a heterozygous PINK1 mutation is sufficient to determine sensory alterations which can be disclosed by a psychophysical task. Deficits in temporal processing might be considered as subclinical signs of alteration at least in PINK1-related parkinsonism.

Well-Timed, Brief Inhibition Can Promote Spiking: Postinhibitory Facilitation

Brief synaptic inhibition can overwhelm a nearly coincident suprathreshold excitatory input to preclude spike generation. Surprisingly, a brief inhibitory event that occurs in a favorable time window preceding an otherwise subthreshold excitation can facilitate spiking. Such postinhibitory facilitation (PIF) requires that the inhibition has a short (decay) time constant tauinh. The timescale ranges of tauinh and of the window (width and timing) for PIF depend on the rates of neuronal subthreshold dynamics. The mechanism for PIF is general, involving reduction by hyperpolarization of some excitability-suppressing factor that is partially recruited at rest. Here we illustrate and analyze PIF, experimentally and theoretically, using brain stem auditory neurons and a conductance-based five-variable model. In this auditory case, PIF timescales are in the sub- to few millisecond range and the primary mechanistic factor is a low-threshold potassium conductance gKLT. Competing dynamic influences create the favorable time window: hyperpolarization that moves V away from threshold and hyperexcitability resulting from reduced gKLT. A two-variable reduced model that retains the dynamics only of V and gKLT displays a similar time window. We analyze this model in the phase plane; its geometry has generic features. Further generalizing, we show that PIF behavior may occur even in a very reduced model with linear subthreshold dynamics, by using an integrate-and-fire model with an accommodating voltage-dependent threshold. Our analyses of PIF provide insights for fast inhibition's facilitatory effects in longer trains. Periodic subthreshold excitatory inputs can lead to firing, even one for one, if brief inhibitory inputs are interleaved within a range of favorable phase lags. The temporal specificity of inhibition's facilitating effect could play a role in temporal processing, in sensitivity to inhibitory and excitatory temporal patterning, in the auditory and other neural systems.

The effects of anterior arcuate and dorsomedial frontal cortex lesions on visually guided eye movements: 2. Paired and multiple targets

This study examined the effects of anterior arcuate and dorsomedial frontal cortex lesions on the execution of saccadic eye movements made to paired and multiple targets in rhesus monkeys. Identical paired targets were presented with various temporal asynchronies to determine the temporal offset required to yield equal probability choices to either target. In the intact animal equal probability choices were typically obtained when the targets appeared simultaneously. After unilateral anterior arcuate lesions a major shift arose in the temporal offset required to obtain equal probability choices for paired targets that necessitated presenting the target in the hemifield contralateral to the lesion more than 100 ms prior to the target in the ipsilateral hemifield. This deficit was still pronounced 1 year after the lesion. Dorsomedial frontal cortex lesions produced much smaller but significant shifts in target selection that recovered more rapidly. Paired lesions produced deficits similar to those observed with anterior arcuate lesions alone. Major deficits were also observed on a multiple target temporal discrimination task after anterior arcuate but not after dorsomedial frontal cortex lesions. These results suggest that the frontal eye fields that reside in anterior bank of the arcuate sulcus play an important role in temporal processing and in target selection. Dorsomedial frontal cortex, that contains the medial eye fields, plays a much less important role in the execution of these tasks.

Left hemisphere selectivity for processing duration in normal subjects

The role of the left cerebral hemisphere for the discrimination of duration was examined in a group of normal subjects. Two tasks were presented: the first required a reaction-time response to the offset of monaural pulse sequences varying in interpulse duration, and the second required the discrimination of small differences in durations, within a delayed-comparison paradigm. In each task a right-ear advantage was obtained when the durations were 50 msec or less. No ear advantage was obtained for the larger durations of 67 to 120 msec. Since the perceptual distinctiveness of phonemes may be provided by durations approximating 50 msec, the nature of the relationship between the left hemisphere's role in temporal processing and speech processing may be elaborated.

Pitch of complex tones for normal and hearing‐impaired listeners

Current pitch models emphasize the ability of the hearing mechanism to resolve spectral components, and either deemphasize or leave unspecified the importance of temporal processing. Our study attempts to assess the relative importance for pitch perception of spectral and temporal encoding. Three groups of listeners were tested in a simple two‐interval pitch DL task: normal listeners, listeners with impaired spectral processing (as indicated by abnormally broad psychophysical tuning curves), and listeners with impaired spectral and temporal processing (as indicated by broad tuning curves and poor gap‐detection performance.) The task was identification of the direction of change of the (missing) fundamental, from one interval to the next, of a four‐component harmonic complex. Pure tone frequency DLs were also measured. All hearing‐impaired listeners performed less well than normals, though listeners with both spectral and temporal deficiencies performed considerably poorer than those with spectral deficiencies alone. Further, pitch DLs were much larger than pure‐tone DLs in listeners with temporal deficiencies. These results suggest that the role of temporal processing in pitch perception may be much greater than current theories indicate. [Work supported by NIH NS12045.]