Biology subjects

Caminiti, R.

Publications and source records attributed to Caminiti, R..

4 recordsLinked to original sources

bioRxiv2023

A cortical mechanism linking saliency detection and motor reactivity in rhesus monkeys

Sudden and surprising sensory events trigger neural processes that swiftly adjust behavior. To study the phylogenesis and the mechanism of this phenomenon, we trained two rhesus monkeys to keep a cursor inside a visual target by exerting force on an isometric joystick. We examined the effect of surprising auditory stimuli on exerted force, scalp electroencephalographic (EEG) activity, and local field potentials (LFP) recorded from the dorso-lateral prefrontal cortex. Auditory stimuli elicited (1) a biphasic modulation of isometric force: a transient decrease followed by a corrective tonic increase, and (2) EEG and LFP deflections dominated by two large negative-positive waves (N70 and P130). The EEG potential was maximal at the scalp vertex, in all respects similar to the human vertex potential. Electrocortical potentials and force were tightly coupled: the P130 amplitude predicted the magnitude of the corrective force increase, particularly in the EEG electrodes contralateral to the limb exerting force, and in the LFP recorded from deep rather than superficial cortical layers, suggesting a direct effect of the vertex potential on the motor output determining the behavior. These results disclose a phylogenetically-preserved cortico-motor mechanism supporting adaptive behavior in response to salient sensory events.

neuroscience↗

bioRxiv2022

Egocentric value maps of the near-body environment

Body-part centric response fields are pervasive: they are observed in single neurons, fMRI, EEG, and multiple behavioural measures. This prevalence across scales and measures makes them excellent candidates for studying systems-level neuroscience. Nonetheless, they remain poorly understood because we lack a unifying formal explanation of their origins and role in wider brain function. Here, we provide such explanation. We use reinforcement learning to analytically explain the existence of body-part centric receptive fields, also known as peripersonal field. We then simulate multiple experimental findings considered foundational in the peripersonal space literature. Our results demonstrate that peripersonal fields naturally arise from two simple and plausible assumptions about living agents: 1) they experience reward when they contact objects in the environment, and 2) they act to maximise reward. These simple assumptions are enough to explain empirical findings on stimulus kinematics, tool use, valence, and network-architecture. Our explanation provides further insight. First, it offers multiple empirically testable predictions. Second, it offers a formal description of the notion that the world-agent state is encoded in parieto-premotor cortices, using motor primitives: peripersonal fields provide building blocks that together create a short-term model of the world near the agent in terms of its future states; a successor representation. This short-term, close-range egocentric peripersonal map is analogous to the long-term, long-range allocentric spatial map of place and grid cells, which underlie locomotion and navigation to reach distant objects. Together, these allocentric and egocentric maps allow efficient interactions with a changing environment across multiple spatial and temporal scales. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=149 SRC="FIGDIR/small/504456v1_ufig1.gif" ALT="Figure 1"> View larger version (68K): org.highwire.dtl.DTLVardef@1c9d635org.highwire.dtl.DTLVardef@e4b1corg.highwire.dtl.DTLVardef@65390borg.highwire.dtl.DTLVardef@1840160_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2021

Evidence Of We-Representation In Monkeys When Acting Together

A hallmark of successful evolution resides in the ability to adapt our actions to those of others, optimizing collective behaviour, to achieve goals otherwise unattainable by individuals acting alone. We have previously shown that macaques constitute a good model to analyse joint behavior, since they are able to coordinate their actions in a dyadic context. In the present work, we investigated whether monkeys could improve their joint-action performance, under special visuomotor conditions. The behavior of 5 monkeys was analyzed in isometric center-out tasks, requiring hand force application in different directions, either individually or together with a partner. Manipulating the presence or absence of a pre-instruction about the future action condition (SOLO or TOGETHER), allowed us to investigate on the existence of a "we-representation" in macaque monkeys. We found that pre-cueing the future action context increased the chances of dyadic success, also thanks to the emergence of an optimal kinematic setting, that ultimately facilitates inter-individual motor coordination. Our results offer empirical evidence in macaques of a "We-representation" during collective behavior, that once is cued in advance has an overall beneficial effect on joint performance.

animal behavior and cognition↗

bioRxiv2021

THE COMPLEX HODOLOGICAL ARCHITECTURE OF THE MACAQUE DORSAL INTRAPARIETAL AREAS AS EMERGING FROM NEURAL TRACERS AND DW-MRI TRACTOGRAPHY

In macaque monkeys, dorsal intraparietal areas are involved in several daily visuo-motor actions. However, their border and sources of cortical afferents remain loosely defined. Through a retrograde tracer and MRI diffusion-based tractography study here we show a complex organization of the dorsal bank of the IPS, which can be subdivided into a rostral area PEip, projecting to the spinal cord, and a caudal area MIP lacking such projections. Both areas include a rostral and a caudal sector, emerging from their ipsilateral, gradient-like connectivity profiles. As tractography estimations, we used the cross-sectional volume of the white matter bundles connecting each area with other parietal and frontal regions, after selecting ROIs corresponding to the injection sites of retrograde tracers. A quantitative analysis between the proportions of cells projecting to all sectors of PEip and MIP along the continuum of the dorsal bank of the IPS and tractography revealed a significant correlation between the two data sets for most connections. Moreover, tractography revealed "false positive" but plausible streamlines awaiting histological validation.

neuroscience↗