Correlations Between Spinal Neurones

Abstract

As shown in the preceding sections, correlations between firing patterns of different neurones in supraspinal structures have led to quite unique models of brain function, which specifically rely on such patterns and which interpret them as a code distinct from the commonly accepted mean firing rate code. Perhaps surprisingly, something equivalent has not happened for the spinal cord level although it will now be shown that similar correlation patterns also occur at this level. Indeed there is some reluctance on the part of many workers to try and set up such hypotheses. Instead, correlations between firings of neurones of the same kind are used as methodological tools to investigate synaptic connectivity, and indeed very successfully so. A prerequisite for building new theoretical frameworks based on neuronal correlations may be the development of the module or neural assembly concept which — as discussed in the Sect. 1.4 — has already “diffused” down at least to the brainstem. If this conceptual prerequisite is in fact essential, the time may be ripe for new views of spinal cord function, all the more so as Mountcastle (1979) and Szentagothai (1983) have already tried to apply it to the spinal cord, albeit from different perspectives. However, the modules are not always clearly defined even at the cortical level (e.g. Creutzfeldt 1983), and they are even less so at the spinal level. The functional modules have yet to be identified. Before entering functional discussions, however, a description of the correlation patterns at spinal cord level is due.

“‘Mass communication is defined as the transfer, among groups, of information that a single individual could not pass to another’. It is not such a bad image, the brain as an ant colony!”

D.R. Hofstadter⁵