The efference cascade, consciousness, and its self: naturalizing the first person pivot of action control.

Bjorn Merker

doi:10.3389/fpsyg.2013.00501

Abstract

The 20 billion neurons of the neocortex have a mere hundred thousand motor neurons by which to express cortical contents in overt behavior. Implemented through a staggered cortical “efference cascade” originating in the descending axons of layer five pyramidal cells throughout the neocortical expanse, this steep convergence accomplishes final integration for action of cortical information through a system of interconnected subcortical way stations. Coherent and effective action control requires the inclusion of a continually updated joint “global best estimate” of current sensory, motivational, and motor circumstances in this process. I have previously proposed that this running best estimate is extracted from cortical probabilistic preliminaries by a subcortical neural “reality model” implementing our conscious sensory phenomenology. As such it must exhibit first person perspectival organization, suggested to derive from formating requirements of the brain's subsystem for gaze control, with the superior colliculus at its base. Gaze movements provide the leading edge of behavior by capturing targets of engagement prior to contact. The rotation-based geometry of directional gaze movements places their implicit origin inside the head, a location recoverable by cortical probabilistic source reconstruction from the rampant primary sensory variance generated by the incessant play of collicularly triggered gaze movements. At the interface between cortex and colliculus lies the dorsal pulvinar. Its unique long-range inhibitory circuitry may precipitate the brain's global best estimate of its momentary circumstances through multiple constraint satisfaction across its afferents from numerous cortical areas and colliculus. As phenomenal content of our sensory awareness, such a global best estimate would exhibit perspectival organization centered on a purely implicit first person origin, inherently incapable of appearing as a phenomenal content of the sensory space it serves.

Highlights

“Given the presumption that the way we see the world evolved to make the control of action as straightforward as possible, it is likely that our phenomenal perception of the world is closely related to the mechanisms we use to act upon it”
Whatever a theory of consciousness might contain or propose, it must provide an account of what it is that places us in a first person perspectival relation to our phenomenal experience
Neither self-consciousness nor a self-image is implied by this usage; to be subject to phenomenal experience suffices

Summary

Bjorn Merker*

Edited by: Ezequiel Morsella, San Francisco State University and University of California, USA. Reviewed by: Ezequiel Morsella, San Francisco State University and University of California, USA T. I have previously proposed that this running best estimate is extracted from cortical probabilistic preliminaries by a subcortical neural “reality model” implementing our conscious sensory phenomenology. As such it must exhibit first person perspectival organization, suggested to derive from formating requirements of the brain’s subsystem for gaze control, with the superior colliculus at its base. Its unique long-range inhibitory circuitry may precipitate the brain’s global best estimate of its momentary circumstances through multiple constraint satisfaction across its afferents from numerous cortical areas and colliculus.

INTRODUCTION

CONCLUSION

Zentralblatt für die Medizinischen

Neurobiology of Saccadic Eye