Biology subjects

Kaminiarz, A.

Publications and source records attributed to Kaminiarz, A..

2 recordsLinked to original sources

bioRxiv2026

The representation of voluntary and reflexive fast eye movements in the macaque lateral intraparietal area (LIP)

The macaque lateral intraparietal area (LIP) is known for its role in visually guided saccades as well as in higher cognitive functions. However, its contribution to more basic visuomotor processes remains unclear. Here, we investigated whether neural activity in area LIP is also related to involuntary reflexive eye movements, specifically the fast phases of optokinetic nystagmus (OKN). To address this question, we compared spiking activity and local field potentials (LFPs) in area LIP of two male macaque monkeys during visually guided saccades and during kinematically similar OKN fast phases. Neurons exhibiting robust perisaccadic activation during voluntary saccades showed markedly reduced or no activity around the time of OKN fast phases and were not modulated by fast-phase amplitude or frequency. Using a Generalized Linear Model, we found that during OKN slow phases, area LIP reliably encoded gaze position and the direction of visual motion driving the reflexive eye movement. LFP analyses further revealed that beta-band power differed between voluntary saccades and OKN fast phases, whereas theta-band phase coherence increased following both types of fast eye movements, suggesting distinct local processing but shared post-movement network coordination. Our results reinforce the view of area LIP as a key area for integrating sensory and cognitive signals relevant for goal-directed action rather than a generic oculomotor controller.

neuroscience↗

bioRxiv2021

Coding of interceptive saccades in parietal cortex of macaque monkeys

The oculomotor system can initiate remarkably accurate saccades towards moving targets (interceptive saccades) the processing of which is still under debate. The generation of these saccades requires the oculomotor centers to have information about the motion parameters of the target that then must be extrapolated to bridge the inherent processing delays. We investigated to what degree the information about motion of a saccade target is available in the lateral intra-parietal area (area LIP) of macaque monkeys for generation of accurate interceptive saccades. When a multi-layer neural network was trained based on neural discharges from area LIP around the time of saccades towards stationary targets it was also able to predict the end points of saccades directed towards moving targets. This prediction, however, lagged behind the actual post-saccadic position of the moving target by ~80 ms when the whole neuronal sample of 105 neurons was used. We further found that single neurons differentially code for the motion of the target. Selecting neurons with the strongest representation of target motion reduced this lag to ~30 ms which represents the position of the moving target approximately at the onset of the interceptive saccade. We conclude that - similarly to recent findings from the Superior Colliculus (Goffart et al., 2017) - there is a continuum of contributions of individual LIP neurons to the accuracy of interceptive saccades. A contribution of other gaze control centers (like the cerebellum or the frontal eye field) that further increase the saccadic accuracy is, however, likely.

neuroscience↗