Space-time trade-offs in human nociceptive system

Speaker: 

Robert C. Coghill 

Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, US

Description of the general focus of the symposium: 

This workshop proposes an integrative perspective on pain as an emergent property of a distributed nociceptive system, building on the conceptual framework introduced by Robert C. Coghill. Rather than being encoded locally or linearly, nociceptive signals are integrated across space and time, giving rise to hallmark features of pain perception such as nonlinearity and disproportionality. The workshop will examine how temporal and spatial dimensions of stimulation can be functionally exchanged—trading time with space—to shape pain in humans. Opening with a keynote by Robert C. Coghill, the workshop will outline the distributed nociceptive system framework and its implications for understanding pain variability, hyperalgesic and hypoalgesic modulations of pain. Subsequent talks will present psychophysical signatures of this framework across temporal and spatial domains. Temporal modulation will be addressed through offset analgesia (J. Poehlmann), demonstrating how small decreases in stimulus intensity evoke disproportionately large reductions in perceived pain. This phenomenon will be discussed as an expression of temporal contrast computation, reflecting the system’s sensitivity to changes over time rather than absolute input levels, and its generalisability across modalities, and experimental contexts. Spatial modulation will be addressed through spatial summation and lateral inhibition (W.M. Adamczyk), demonstrating how pain intensity reflects nonlinear integration of distributed nociceptive inputs, in which increasing stimulated area can paradoxically amplify or suppress pain as a function of spatial configuration, inter-site interactions, and attentional selection of nociceptive subregions. The thermonociceptive illusions, such as the Thermal Grill and Paradoxical Heat Sensation (A. Mitchell) will be examined as a canonical case of emergent nociceptive perception, in which spatially and temporally interleaved innocuous warm and cool inputs are integrated across populations of thermosensory and nociceptive neurons, producing a pain percept that cannot be attributed to any single stimulation site and instead reflects distributed spatial contrast computations. Across paradigms, the workshop will emphasize shared computational principles, including contrast enhancement, distributed integration, and attentional mediation. By bridging classical psychophysics with contemporary systems neuroscience, this symposium aims to provide a unifying mechanistic framework for spatial and temporal pain modulation, stimulate novel experimental approaches, and advance understanding of pain processing in both health and disease—making it highly relevant for the Neuronus IBRO Forum audience. 

Brief description of the talk: 

A new overarching conceptual framework for understanding pain, termed the Distributed Nociceptive System (DNS), integrates two neglected concepts - population coding and distributed processing. The central tenet of this framework is that the extraction and utilization of nociceptive information is a process that can be accomplished separately and largely independently by populations of neurons across multiple sites within the central nervous system. As such, processing of nociceptive information can occur in a highly distributed fashion, yielding a system that is very resistant to disruption. The DNS provides a bridge between the basic neuroscience and clinical worlds by providing a mechanistic framework for developing an understanding of the perplexing symptoms of chronic pain. For example, altered receptive field tuning may result in enhanced recruitment of nociceptive neurons and spread of pain. Thus, examining systems supporting spatial tuning may provide important insights into how pain can spread and how this spread can be reversed. Moreover, the widely distributed brain systems that are involved in the construction of the pain experience may require distributed regulation to instantiate either positive or negative changes.