Global operations theory of the interval timing clock from cortico-striatal-thalamic loop feedback

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Description: Understanding the physiological mechanisms underlying the experience of time passing was the objective of this research. Several models have been formulated to attempt to explain how we, as well as many species across a wide range of classes, are capable of learning about temporal contingencies between a stimulus' onset and a reward delivered after the passage of time. Few of these models offer a specific physiological explanation for the origin of the interval timing clock signal, and only one, Striatal Beat Frequency, attempts to explain the necessary information processing elements in terms of the specific neuroanatomy that has been implicated in timing tasks--the prefrontal cortex, dorsal striatum, and thalamic nuclei that comprise a cortico-striatal-thalamic loop. However, Striatal Beat Frequency has several shortcomings that render it an incomplete explanation of temporal perception. An extension of striatal beat frequency was therefore offered which suggests that the temporal signal found within the cortico-striatal-thalamic loop may be the result of the loop activity itself, a feedback process in which the temporal signal results from the global operation of the elements of the cortico-striatal-thalamic loop. To test the hypothesis that cyclical loop activity is necessary and may be the source of the temporal signal, a disconnection technique was implemented to functionally eliminate interaction of elements within this loop. This procedure was not found to eliminate the ability to discriminate temporal duration. An understanding of the locus of the ability to time an interval remains unclear.
Language: English
Format: Degree Work