Publications by authors named "Pascal Warnaar"
The investigation of the dynamics of Purkinje cell (PC) activity is crucial to unravel the role of the cerebellum in motor control, learning and cognitive processes. Within the cerebellar cortex (CC), these neurons receive all the incoming sensory and motor information, transform it and generate the entire cerebellar output. The relatively homogenous and repetitive structure of the CC, common to all vertebrate species, suggests a single computation mechanism shared across all PCs.
View Article and Find Full Text PDFDopamine signals in the striatum are critical for motivated behavior. However, their regional specificity and precise information content are actively debated. Dopaminergic projections to the striatum are topographically organized.
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- - Habits develop as automatic behaviors due to repeated actions, with dopamine playing a key role in this process, particularly in specific brain regions like the ventral, dorsomedial, and dorsolateral striatum.
- - In a study with rats over a 10-week training period, dopamine release was measured in these regions, revealing stable dopamine levels during habit formation, challenging previous assumptions about regional shifts in dopamine signaling.
- - Notably, only the dorsomedial striatum showed varying dopamine levels related to habit formation, suggesting that this region, previously linked to non-habitual behavior, has a significant role in establishing habits.
Inferior olivary activity causes both short-term and long-term changes in cerebellar output underlying motor performance and motor learning. Many of its neurons engage in coherent subthreshold oscillations and are extensively coupled via gap junctions. Studies in reduced preparations suggest that these properties promote rhythmic, synchronized output.
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- Purkinje cells in the cerebellum are crucial for integrating sensory information with motor signals to fine-tune movement control based on behavioral and environmental demands.* -
- New research shows that climbing fibres transmitting sensory information to Purkinje cells can convey multiple types of sensory data and are influenced by previous activity levels, suggesting a complex networking of sensory input.* -
- The study found that individual Purkinje cells tend to receive inputs from different sensory modalities, with variations in climbing fibre responses based on their recent activity, indicating a need for adaptability in motor function.*
Article Synopsis
- Cerebellar plasticity is essential for motor learning, but its mechanisms remain unclear.
- Researchers devised a protocol to study whisker movement reflex in mice by recording Purkinje cell activity.
- Training enhanced Purkinje cell activity, leading it to precede behavioral responses, and this change depended on functional synapses between parallel fibers and Purkinje cells.
Article Synopsis
- Climbing fiber-triggered complex spikes (CS) in cerebellar Purkinje cells (PC) show diverse waveforms with different durations and spikelet components, especially during saccades in awake macaques.* -
- The initial part of the CS remains consistent, but later segments vary significantly due to timing jitter in the last spikelets, which affects total CS duration without impacting subsequent simple spike patterns.* -
- The variability in spikelet timing correlates with the intervals between CS, suggesting that changes in CS frequency affect the excitability of Purkinje cells, a phenomenon also observed in rat models during slice experiments.*