Macaques

Saccades are ballistic eye movements made 2-4 times a second while viewing a visual scene. They change object locations on the retina and visual information relayed to the cortex, yet do not interfere with a stable percept. A mechanism by which the visual cortex accomplishes this visual continuity is predictive remapping of receptive fields (RF) of neurons: neurons across visual and oculomotor areas predictively respond to visual stimuli that will appear in their receptive field after an impending saccade. This update of visual representations is mediated by an efferent motor-to-sensory signal

…patches’ in the brain of humans, macaques and marmosets : these regions of cortex selectively respond to conspecific vocalizations, but little is known about how individual voice patch neurons encode vocal information, particularly on caller identity. The ‘Norm-based coding’ hypothesis from face perception research suggests that neuronal activity could be modulated by the acoustical

…optogenetic techniques from rodents to macaques as an intermediate step towards humans has proven to be challenging. Here we present prelimnary results, directly comparing effects obtained from optogenetic vs electrical stimulation of macaque V1.We injected AAV9-CamKIIa-ChrimsonR-mScarlet-KV2.1 into macaque V1 under electrophysiological guidance. We first investigated neural activity in response

…differs between humans and awake macaques. In humans, the AMG-mPFC FC displays U-shaped pattern along the corpus callosum: a positive FC with the ventromedial p

…We previously showed that macaques playing a video game in a controlled laboratory setting are able to perform joint actions (JA) successfully, when asked to control moving visual cursors displayed on a screen. Yet, while error monitoring is fundamental to optimize motor dyadic performances, it remains unexplored whether macaques are aware of acting together in this abstract context. To fill this gap, we analyzed spontaneous task-unrelated head movements during dyadic performance to investigate their awa

Recent data in macaques showed that the laminar distribution pattern of corticostriatal neurons in the ipsilateral hemisphere largely varied across different areas, independently from density and projecting area, but likely according to the target striatal zone (Borra et al., JNeurosci 2021, 41:1455–69). Furthermore, other data showed that in macaque there are robust crossed corticostriatal projections to the caudate and the putamen (up to 30% of total labeled cells) and that the origin of the direct and the crossed corticostriatal projections is not symmetrical (Borra et al. JNeurosci 2022, 4

…acting in a dyadic context, and that macaques, as humans, leverage on a “we-representation”, suggesting phylogenetically preserved neural processes. At neural level, we showed in macaque dorsal premotor (PMd/F2) cortex the existence of a population of cells, preferentia

Selective visual attention is a key feature of adaptive behavior, improving stimulus detection and response speed. Although it is well established that several measures of neural activity are modulated by attention in many brain areas, it is unclear whether and how these changes in activity correlate with behavior and how different cell types contribute to these mechanisms. To unravel the link between the behavioral benefits induced by spatial attention and its neuronal mechanisms, we analyzed neuronal responses obtained from simultaneous extracellular recordings in PFC and visual area V4 of t

Approximately 20M people worldwise suffer from blindness that cannot benefit from recent genetic and neuroprosthesis developments in the retina. Stimulation of the brain visual pathways has been a promising strategy by inducing artificial percepts of light in blind patients through microstimulation using penetrating microelectrodes. Yet, the clinical translation of such a strategy is still challenging due to biological reactions to the implanted device. In this project we aim to build an optogenetic visual prosthesis that interfaces with the lateral geniculate nucleus (LGN).First in mice, a bl

…our laboratory has shown, in macaques, that transient inactivation of the hippocampus by intracerebral infusion of the GABAA agonist mu

Visual decisions typically require accumulation of uncertain sensory information to make inferences about the state of the world. This inference process is complicated by the fact that the state of the world can change, which often requires adjustments in how sensory information is accumulated. Previous work has modeled optimal inference in these changing environments [1-2]. One key feature of these models is a leakage of accumulated evidence, where the leak rate depends on environmental stability. For example, in more unstable environments, an increased leak rate helps remove pre-change evide

A central problem in neuroscience is to understand how the dynamics of neural populations support computation. These dynamics are created both by the local neural circuitry as well as the inputs to that circuit from other brain regions. Hence, characterizing how inputs drive different population responses is key to understanding how brain circuits are modulated to flexibly produce different behaviors. To this end, we developed a patterned microstimulation (uStim) protocol that allowed us to finely manipulate the activity of a neural population in a given area by directly stimulating the same p

Understanding how internally driven cognitive processes (COPs) give rise to behavior in different species is one of the key challenges in systems neuroscience. Traditionally, neuroscience has aimed to isolate individual COPs by simplifying sensory stimuli and behavioral readouts. Yet in natural behavior, several COPs can co-occur, often with overlapping neural representations. The dynamics of such superimposed COPs are yet to be understood, as well as the extent to which they generalize across species. To tackle this question, we developed a naturalistic Virtual Reality setup in which two spec

What we expect to see can greatly affect what we perceive. How does expectation influence local circuitry among visual cortical neurons to allow for perceptual discrimination in the context of rich natural inputs? Little work has sought to understand how populations of sensory cortical neurons change their responses with expectation, and the majority of studies manipulate expectation in a task-irrelevant way, disallowing for comparisons of changes in neural activity with behavioral performance. Theoretical and experimental work indicates that changes at the population level, in particular thos

A central problem in neuroscience is to understand how areas in the brain communicate. Inputs to brain areas largely influence the intrinsic dynamics of each region, which shapes ongoing computations. Hence, characterizing how inputs drive different population responses is key to understanding how brain circuits are controlled to generate different behaviors. To this end, we developed an inter-areal patterned microstimulation (uStim) protocol that allowed us to finely manipulate the activity of a neural population in one brain area while simultaneously recording the activity of a second popula

…we asked whether spatial occupancy of macaques (Macaca fascicularis

…neural circuits for decision-making in macaques. This was possible thanks to innovative experimental tasks eliciting sophisticated behaviour, bridging the human and non-human primate research traditions. Firstly, I will describe a specialised medial frontal circuit for novel choice in macaques. Traditionally, monkeys receive extensive training before neural data can be

According to the theory of predictive processing, expectations modulate neural activity so as to optimize the processing of sensory inputs expected in the current environment. While there is accumulating evidence that the brain indeed operates under this principle, most of the attention has been placed on mechanisms that rely on static coding properties of neurons. The potential contribution of dynamical features, such as those reflected in the evolution of neural population dynamics, has thus far been overlooked. In this talk, I will present evidence for a novel mechanism for predictive proce