Abstract
Visual neuroscience aims to model the occipitoventral pathway as a hierarchically organised network of interconnected brain regions that process information to perceive and categorize complex visual scenes. Here, we investigated an important component of these mechanisms: the explicit transfer of features from their early coding in the occipital cortex to their later coding in the right fusiform (rFG) involved in higher-level processing. Five observers identified either "the Nuns" or "Voltaire" in Dali's ambiguous painting Slave Market with Disappearing Bust of Voltaire from visual information randomly sampled on each trial with Bubbles (see SuppFig A). Across trails (mean=3396, range 2885-4154), for each observer we quantified with Mutual Information (MI) the diagnostic features underlying each perceptual decision (see SuppFig A). A similar analysis performed on brain activity measured with MEG localized to 12773 sources, 0-400ms post-stimulus, revealed the spatio-temporal pattern of diagnostic feature coding in the occipitoventral pathway. We then explicitly tested diagnostic feature transfer from early sending sources in occipital cortex to later receiving sources in the rFG. According to the Weiner-Grainger framework, a casual transfer of a representation would occur if a diagnostic feature is represented equivalently (revealed with information theoretic temporal redundancy) in "Sender" at time t1, then at "Receiver" at a later time t2(but not at t1). Thus, for each receiving rFG source we selected the putative "sender" as the occipital cortex source with the highest coding of diagnostic feature (i.e. highest MI) prior (>10) to the peak coding of the receiver and computed feature transfer. Our results reveal a transfer of diagnostic features from occipital cortex to rFG (see SuppFig B and C). Here, we reconstructed a dynamic information proceeding network in the occipitoventral pathway that codes and transfer the specific features underlying perceptual decisions.
Meeting abstract presented at VSS 2018