Toward a neurobiology of temporal cognition: advances and challenges (original) (raw)

The neural representation of time

Current Opinion in Neurobiology, 2004

This review summarizes recent investigations of temporal processing. We focus on motor and perceptual tasks in which crucial events span hundreds of milliseconds. One key question concerns whether the representation of temporal information is dependent on a specialized system, distributed across a network of neural regions, or computed in a local task-dependent manner. Consistent with the specialized system framework, the cerebellum is associated with various tasks that require precise timing. Computational models of timing mechanisms within the cerebellar cortex are beginning to motivate physiological studies. Emphasis has also been placed on the basal ganglia as a specialized timing system, particularly for longer intervals. We outline an alternative hypothesis in which this structure is associated with decision processes.

Neuroanatomical and Neurochemical Substrates of Timing

We all have a sense of time. Yet, there are no sensory receptors specifically dedicated for perceiving time. It is an almost uniquely intangible sensation: we cannot see time in the way that we see color, shape, or even location. So how is time represented in the brain? We explore the neural substrates of metrical representations of time such as duration estimation (explicit timing) or temporal expectation (implicit timing). Basal ganglia (BG), supplementary motor area, cerebellum, and prefrontal cortex have all been linked to the explicit estimation of duration. However, each region may have a functionally discrete role and will be differentially implicated depending upon task context. Among these, the dorsal striatum of the BG and, more specifically, its ascending nigrostriatal dopaminergic pathway seems to be the most crucial of these regions, as shown by converging functional neuroimaging, neuropsychological, and psychopharmacological investigations in humans, as well as lesion and pharmacological studies in animals. Moreover, neuronal firing rates in both striatal and interconnected frontal areas vary as a function of duration, suggesting a neurophysiological mechanism for the representation of time in the brain, with the excitatory-inhibitory balance of interactions among distinct subtypes of striatal neuron serving to fine-tune temporal accuracy and precision.

Dedicated and intrinsic models of time perception

Trends in Cognitive Sciences, 2008

Two general frameworks have been articulated to describe how the passage of time is perceived. One emphasizes that the judgment of the duration of a stimulus depends on the operation of dedicated neural mechanisms specialized for representing the temporal relationships between events. Alternatively, the representation of duration could be ubiquitous, arising from the intrinsic dynamics of nondedicated neural mechanisms. In such models, duration might be encoded directly through the amount of activation of sensory processes or as spatial patterns of activity in a network of neurons. Although intrinsic models are neurally plausible, we highlight several issues that must be addressed before we dispense with models of duration perception that are based on dedicated processes.

Time and memory: towards a pacemaker-free theory of interval timing

Journal of The Experimental Analysis of Behavior, 1999

A popular view of interval timing in animals is that it is driven by a discrete pacemaker-accumulator mechanism that yields a linear scale for encoded time. But these mechanisms are fundamentally at odds with the Weber law property of interval timing, and experiments that support linear encoded time can be interpreted in other ways. We argue that the dominant pacemaker-accumulator theory, scalar expectancy theory (SET), fails to explain some basic properties of operant behavior on interval-timing procedures and can only accommodate a number of discrepancies by modifications and elaborations that raise questions about the entire theory. We propose an alternative that is based on principles of memory dynamics derived from the multiple-time-scale (MTS) model of habituation. The MTS timing model can account for data from a wide variety of time-related experiments: proportional and Weber law temporal discrimination, transient as well as persistent effects of reinforcement omission and reinforcement magnitude, bisection, the discrimination of relative as well as absolute duration, and the choose-short effect and its analogue in number-discrimination experiments. Resemblances between timing and counting are an automatic consequence of the model. We also argue that the transient and persistent effects of drugs on time estimates can be interpreted as well within MTS theory as in SET. Recent real-time physiological data conform in surprising detail to the assumptions of the MTS habituation model. Comparisons between the two views suggest a number of novel experiments.

Temporal Rhythms and Cerebral Rhythms

Annals of the New York Academy of Sciences, 1984

Hoagland' appears to have been the first to suggest that the ability to make temporal judgments may depend on the possession of a temporal pacemaker or internal clock, analogous to the pacemaker cells responsible for many physiological rhythms. This valuable insight has stimulated much research. To get full benefit from the hypothesis, however, two things must be borne in mind. The first is that the hypothesis of a pacemaker needs to be supplemented by further mechanisms to explain performance: I shall use the term "pacemaker" for the source of the temporal reference frequency, and the term "internal clock" for the complete set of mechanisms. The second consideration is that an adequate model should aim at explaining not just one facet of time judgment, but as many of its features as possible.

Editorial: Understanding the Role of the Time Dimension in the Brain Information Processing

Frontiers in psychology, 2017

Editorial on the Research Topic Understanding the Role of the Time Dimension in the Brain Information Processing An accurate representation of time-dimension in the neuronal circuits is required for a successful interaction of the brain with the four-dimensional physical world. Time-dimension, unlike other three dimensions of our physical universe, is never perceived as a novelty, but only reported as the flow of time. As there are no known neurological or psychiatric disorders that are associated with the loss of the sense of flow of time, this suggests that the functions of the brain involve processing of temporal information (Merchant et al., 2013). Moreover, psychological flow of time is likely the result of the perception of the physical nature of the time-dimension. The information about a stimulus coded by neural circuits can be understood in terms of Shannon information, which is the arrangement of spikes (an absence or presence) in timebins of specific size along the time-dimension (Gupta and Chen, 2016a,b). Thus, Shannon information inherently incoporates time-bin as the time-dimension in information processing. Encoded stimulus characteristic, can be decoded or utilized in brain circuits by processing this information, referred as the temporal processing of information. Thus, it is implicit that the information processing, underlying various cognitive functions of the brain, is coupled with the invariant time-dimension. Several novel findings are reported in this Special Issue, which bring us closer to understanding the role of the time-dimension in the brain information processing. These include the representation of the physical time in neural circuits, temporal processing of information, the role of prior information in the internal representation of rhythmic time, and neural oscillations in timing behavior and perception. BRAIN OSCILLATIONS IN TIMING BEHAVIOR AND PERCEPTION Brain oscillations are a key element on information processing and play a crucial role in the communication between and within different cortical and subcortical areas (Buzsáki, 2006). Neural oscillations have been linked to different high cognitive functions of which timing and time perception constitute one of the most studied (