Action Selection in the Midbrain: Neuromodulation of Visuomotor Senses

Projektinformationen

JANUS

ID Finanzhilfevereinbarung: 101086580

DOI

10.3030/101086580

EK-Unterschriftsdatum 16 Februar 2023

Startdatum 1 Oktober 2023

Enddatum 30 September 2028

Finanziert unter

• European Research Council (ERC)

Gesamtkosten

€ 1 998 430,00

EU-Beitrag

€ 1 998 430,00

Koordiniert durch

INSTITUTE OF SCIENCE AND TECHNOLOGY AUSTRIA
Austria

Periodic Reporting for period 1 - JANUS (Action Selection in the Midbrain: Neuromodulation of Visuomotor Senses)

Berichtszeitraum: 2023-10-01 bis 2026-03-31

Zusammenfassung vom Kontext und den Gesamtzielen des Projekts

Efficient sensory processing depends on the brain’s ability to dynamically allocate resources to the most relevant information on a moment-to-moment basis, based on internal state and behavioral context. The superior colliculus (SC), a midbrain structure that transforms visual signals into coordinated movements and shifts of attention, plays a central role in this process. For example, the brain must distinguish between visual changes caused by self-motion and those caused by external events, responding differently to expected versus unexpected stimuli. Traditionally, visual processing has been viewed as a one-way, feedforward flow of information from the retina to higher brain areas. However, this view overlooks the critical role of neuromodulation—chemical signaling systems such as dopamine, serotonin, and acetylcholine—that adjust neuronal activity according to motivation, novelty, arousal, and threat. These systems influence sensory gain, attention, and behavioral selection across the brain. Notably, the SC receives modulatory input as extensively as direct visual input, suggesting that contextual signals shape visual processing at very early stages. Despite its importance, the functional impact of neuromodulation on SC activity remains poorly understood, largely due to the difficulty of measuring multiple interacting systems simultaneously in behaving animals. The JANUS project addresses this gap by developing a comprehensive framework to study how brain states and neuromodulation influence sensory processing, visuomotor coordination, and decision-making. Our objectives are: (Aim 1) to quantify how visual and non-visual signals interact within the SC in real time; (Aim 2) to determine how neuromodulatory systems coordinate to influence sensory processing, attention, and goal-directed behavior; and (Aim 3) to uncover how neuromodulation alters neural connectivity and population dynamics to guide visuomotor decision-making. Together, these aims will define how neuromodulation fine-tunes perception and action in dynamic environments.

Arbeit, die ab Beginn des Projekts bis zum Ende des durch den Bericht erfassten Berichtszeitraums geleistet wurde, und die wichtigsten bis dahin erzielten Ergebnisse

During the first period, we (1) identified a core mechanism that stabilizes vision during movement (Vega-Zuniga et al., 2025). We uncovered a hub-and-spoke network centered in the ventral lateral geniculate nucleus (vLGN) that integrates motor signals to distinguish self-generated from external sensory events (Aim 2a,b).

In the second period, we (2) extended our work on adaptation versus invariance in early vision (Aim 1a,b), showing that luminance shifts spike timing by up to 25 ms, while relative spike timing remains stable—providing an invariant code for perception under natural conditions (Gupta, Patel, et al. in preparation). In parallel, we (3) discovered intrinsic, stimulus-independent population dynamics in the superior colliculus (SC) that track learning, attention, and performance, and interact with sensory input on single trials to shape visual encoding (Schmidt et al., in submission; Aim 1a,b) (Schmidt, et al. in submission). Focusing on neuromodulation, we (4) showed that noradrenaline from the locus coeruleus shifts the excitatory–inhibitory balance in SC circuits, likely gating specific visuomotor transformations (Aim 2c, 3a,b). We further (5) investigated serotonergic dysregulation in ASD, revealing sensory deficits, though linking these to behavior remains ongoing (Aim 2c).

Currently, we are (6) initiating studies of dopaminergic signaling in the SC (Aim 3a,b) and (7) developing theoretical frameworks of invariance to understand how stable decoding is maintained across changing neuromodulatory states (Aim 1a,b).

Finally, (8) as part of a side project, we contributed to retinal circuit studies with Yi-Rong Peng (UCLA), shedding light on the connectivity logic that gives rise to computation (Cavallini, Quiroli, et al., submitted), with insights and approaches developed during the ERC supporting this work.

Fortschritte, die über den aktuellen Stand der Technik hinausgehen und voraussichtliche potenzielle Auswirkungen (einschließlich der bis dato erzielten sozioökonomischen Auswirkungen und weiter gefassten gesellschaftlichen Auswirkungen des Projekts)

Our work identifies core mechanisms by which the brain maintains stable perception while supporting adaptive behavior. We reveal a thalamic hub that stabilizes vision during movement, intrinsic attention-related dynamics in the superior colliculus, and neuromodulatory processes that regulate sensory processing and action. Together, these findings establish early vision as an active, state-dependent process and demonstrate how neuromodulation links perception to behavior. This framework has broad implications for systems neuroscience and attention, and, in the longer term, for clinical research, where dysfunctions in neuromodulatory systems are implicated in a range of neuropsychiatric and neurological disorders.