PT  - JOURNAL ARTICLE
AU  - Elia Shahbazi
AU  - Timothy Ma
AU  - Martin Pernuš
AU  - Walter Scheirer
AU  - Arash Afraz
TI  - Perceptography: unveiling visual perceptual hallucinations induced by optogenetic stimulation of the inferior temporal cortex
AID  - 10.1101/2022.10.24.513337
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.10.24.513337
4099  - http://biorxiv.org/content/early/2022/10/25/2022.10.24.513337.short
4100  - http://biorxiv.org/content/early/2022/10/25/2022.10.24.513337.full
AB  - Artificial perturbation of local neural activity in the high-level visual cortex alters visual perception. Quantitative characterization of these perceptual alterations holds the key to the development of a mechanistic theory of visual perception 1. Historically, though, the complexity of these perceptual alterations, as well as their subjective nature, has rendered them difficult to quantify. Here, we trained macaque monkeys to detect and report brief optogenetic impulses delivered to their inferior temporal cortex, the high-level visual area associated with object recognition, via an implanted LED array2. We assumed that the animals perform this task by detecting the stimulation-induced alterations of the contents of their vision. We required the animals to fixate on a set of images during the task and utilized a machine-learning structure aiming at physically perturbing the viewed images in order to trick the animals into thinking they were being stimulated. In a high-throughput iterative process of behavioral data collection, we developed highly specific perturbed images, perceptograms, looking at which would trick the animals into feeling cortically stimulated. Perceptograms provide parametric and pictorial evidence of the visual hallucinations induced by cortical stimulation. Objective characterization of stimulation-induced perceptual events, besides its theoretical value, opens the door to making better visual prosthetic devices as well as a deeper understanding of visual hallucinations in mental disorders.Competing Interest StatementThe authors have declared no competing interest.