Single-neuron correlates of subjective vision in the human medial temporal lobe

Abstract

Visual information from the environment is transformed into perceptual sensations through several stages of neuronal processing. Flash suppression constitutes a striking example in which the same retinal input can give rise to two different conscious visual percepts. We directly recorded the responses of individual neurons during flash suppression in the human amygdala, entorhinal cortex, hippocampus, and parahippocampal gyrus, allowing us to explore the neuronal responses in untrained subjects at a high spatial and temporal resolution in the medial temporal lobe. Subjects were patients with pharmacologically intractable epilepsy implanted with depth electrodes to localize the seizure onset focus. We observed that the activity of two thirds of all visually selective neurons followed the perceptual alternations rather than the retinal input. None of the selective neurons responded to a perceptually suppressed stimulus. Therefore, the activity of most individual neurons in the medial temporal lobe of naive human subjects directly correlates with the phenomenal visual experience.

A low-dimensional model of binocular rivalry using winnerless competition

“…To account for the empirical data on the role of stimulus properties in binocular rivalry [19,4,5], as well as on its neurophysiological correlates [9,11,18,29], a number of models have been put forward, most of which have been based on a reciprocal inhibition architecture, whereby the parts of the system that code for the two competing percepts suppress each other [3,10,14,15,16,20,30]. Dominance switching is typically instantiated via slow negative feedback (e.g.…”

Unconscious processing dissociates along categorical lines

“…It is known that posterior parietal/dorsal occipital regions show greater activation for tool stimuli compared with face stimuli when those stimuli are rendered invisible with CFS, whereas categoryspecific neural responses within the ventral stream to the same stimuli are obliterated (18; see also, [19][20][21][22]. In experiments 1-5, we used this property of the CFS paradigm to demonstrate that information processed by the dorsal stream influences, online, the overt retrieval of semantic knowledge about tools but not nonmanipulable things.…”

Intracranial neuronal ensemble recordings and analysis in epilepsy

“…In contrast, the disadvantage of microarrays placed within macroarrays lies in the difficulty to control the implantation depth and therefore the cortical (or subcortical) layer it probes. This type of paired micro/macroelectrode is typically to study activity from deep structures such as the mesial temporal lobe (Jacobs et al, 2007;Kreiman et al, 2002;Ogren et al, 2009;Quiroga et al, 2005) or frontoparieto-medial surfaces (Halgren et al, 2015). Due to the nature of its design, neocortical sites cannot be approached by this technique.…”