Biology subjects

Krauzlis, R.

Publications and source records attributed to Krauzlis, R..

3 recordsLinked to original sources

bioRxiv2026

Neuronal processing of facial expressions in the primate superior colliculus

Fast processing of emotionally salient facial expressions is widely believed to depend on a subcortical visual circuit from the superior colliculus through the thalamus to the amygdala, but the specific processing steps remain unclear. Here we identified two largely nonoverlapping groups of neurons in the superior colliculus significantly modulated by facial expressions. One group exhibited a short-latency preference for threat and the other exhibited a delayed preference for fear.

neuroscience↗

bioRxiv2026

Parallel basal ganglia and frontal cortical outputs differentially encode context-dependent evaluation and categorical commitment during choice

Adaptive choice requires transforming the evaluation of available options into commitment to a specific action but understanding how this transformation is implemented across neural circuits remains a central challenge. Here we recorded well-isolated neurons in the substantia nigra pars reticulata (SNr) and frontal eye field (FEF), which send parallel projections to the superior colliculus for driving the eye movement choice, while monkeys performed a sequential-offer choice task designed to partially dissociate scene-defined ordinal rank from the categorical commitment. Before target onset, SNr displayed stronger scene-related modulation than FEF. During target evaluation, SNr activity showed ordered modulation across behavioral outcomes dominated by ordinal rank, whereas FEF activity categorically separated acceptance from rejection and strongly encoded target direction. Behavioral model decomposition revealed that ordinal rank alone best explained SNr activity, outperforming both reward magnitude and even a composite acceptability measure that incorporated rank together with reward, scene context, and waiting cost, whereas FEF activity was best explained by categorical commitment. This dissociation was consistent across multivariable modeling, single-neuron response patterns, and all three monkeys. Together, these findings support a division of labor in which context-dependent evaluation and categorical commitment are distributed across parallel basal ganglia and frontal cortical output pathways to efficiently guide voluntary choices.

neuroscience↗

bioRxiv2018

Covert spatial selection in primate basal ganglia

The basal ganglia are important for action selection. They are also implicated in perceptual and cognitive functions that seem far removed from motor control. Here, we tested whether the role of the basal ganglia in selection extends to non-motor aspects of behavior by recording neuronal activity in the caudate nucleus while animals performed a covert spatial attention task. We found that caudate neurons strongly select the spatial location of the relevant stimulus throughout the task even in the absence of any overt action. This spatially selective activity was dependent on task and visual conditions, and could be dissociated from goal-directed actions. Caudate activity was also sufficient to correctly identify every epoch in the covert attention task. These results provide a novel perspective on mechanisms of attention by demonstrating that the basal ganglia are involved in spatial selection and tracking of behavioral states even in the absence of overt orienting movements.

neuroscience↗