About this Research Topic
A representation of physical surroundings in the neuronal circuits is required for the normal information processing by the brain. Physical surroundings are represented in four basic dimensions, which include three geometric dimensions and physical time. There are additional levels of the representation of physical surroundings, which include color, texture and sound quality. Dimension of time is most consistently represented, even in the absence of different sensory stimulation. Representation of time in neuronal circuits is responsible for the temporal order of information reaching the nervous system, which is important for information processing. Moreover, for a successful interaction with physical surroundings, it is required that there is an accurate transfer of physical time information into circuits in the brain; this commonly results from the processing of sensory and motor information. The maintenance of equivalency of time representation in neuronal circuits and external events indicates that the processing of various types of information occurs together with the processing of temporal information. For example, neuronal circuits processing motor movements, also process the time interval during a particular movement. Output from circuits in primary motor area producing motor movements is processed from inputs from many sources. Information represented in the output of a motor neuron is at least two-fold. A recording of the motor neuron activity measures the rate of its firing. An observation of the muscle fiber, with the help of a physical clock, will show a contraction occurring over a time-duration. The activity of the motor neuron represents information processed from sensory and other cortical inputs, while the duration of the contraction of the muscle fiber represents a physical time interval. This simple example illustrates how (motor) information processing is coupled with the temporal processing. The preceding scenario, which is specific to the processing of motor information, may be readily applied to other cortical functions, such as planning or the conscious measurement of time, when one envisions, for example, neurons in the prefrontal cortex in place of neurons in the primary motor cortex.
Several examples reveal a relationship between information processing and temporal processing. Ternus illusion or effect is the perception of apparent group motion or individual motion, which depends on the inter-stimulus interval. While the Ternus illusion is the effect of the duration on the sensory processing, sensory processes also influence interval timing. For example, larger magnitude, more complex, or intense stimuli expand perceived duration, whereas repeated, high-probability, and non-salient stimuli compress time. The role of temporal processing in information processing goes beyond the interval timing. The representation of temporal order in information processing is also important for working memory, planning and normal thought processes.
To help shed light on the association between temporal and information processing, we urge researchers to submit articles in any acceptable format to this Research Topic. Questions may be asked at the level of a single neuron, circuits and brain regions. Recent advances in techniques, for example, optogenetics, as well as sophisticated uses of computational tools, such as multivariate pattern analysis of fMRI data, spectral power analysis, and long range temporal correlations have increased our ability to address such questions. Some answers will be also obtained from ongoing studies of a broad spectrum of clinical disorders, such as Parkinson’s disease and schizophrenia, which affect the temporal processing at various levels of information processing in the brain.
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