The work in NUMEROUS takes place in 3 interrelated work-packages.
WP1 delineates the brain regions involved in tasks that probe conscious awareness in monkeys (Storm et al., Neuron, 2024; Roelfsema, Neuron, 2023). We recently published a large-scale data set called the THINGS ventral stream spiking dataset (TVSD), in which we extensively sampled neuronal activity in response to >25,000 natural images (Papale et al., Neuron, 2025). We anticipate that other researchers will use the TVSD to answer questions about neuronal tuning, analyse the interactions within and between cortical regions, and to compare spiking activity in monkeys to human neuroimaging data. We have also created a neural network models for the processes that shift attention across visual stimuli, modelling brain activity related to shifts of attention (Mollard et al., PLoS Comput. Biol., 2024), intimately related to entry into consciousness.
WP2 investigates memory. Items that are attended within working memory are in access awareness and we compare these items to the representation of memory items that are accessory, i.e. are relevant for a later task. We addressed this comparison by measuring the influence of pronouns on conceptual representations (Dijksterhuis et al., Science, 2024). We recorded from neurons in the human hippocampus during reading and found that concept cells that were selective to a particular noun were later reactivated by pronouns that refer to the cells’ preferred noun. These results provided new insight in how concept cells contribute to the reactivation of concepts in working memory, in particular when they become part of access consciousness because they are cued by the pronoun.
WP3 examines how well subjects are able to report the electrical activation of neurons in the different regions of the brain. The goal is to map the minimal currents necessary for the perception of electrical stimulation throughout the brain and examine the brain regions that are also activated with fMRI in monkeys and how they depend on the ability to report. We have accomplished the technical hurdles for implanting the stimulation electrodes in many positions in the brain. We will use a variant of the electrodes that have been described in Orlemann et al. (2024).
