To address this question, the researchers used mouse models undergoing repeated motor training tasks, including the rotarod test, which measures motor coordination and learning. Using advanced imaging tools that can track individual synaptic components, the team observed a marked increase in astrocyte-mediated synapse elimination as motor learning progressed. In contrast, other glial cell types, such as microglia and oligodendrocyte precursor cells, showed no significant changes under the same experimental conditions, indicating a specific role for astrocytes in this process.

The researchers identified MEGF10, a phagocytic receptor expressed in astrocytes, as a key molecular mediator of this remodeling. When MEGF10 was selectively deleted in astrocytes, mice exhibited impaired motor learning and significant disruptions in communication between the motor cortex and the striatum. In addition, both long-term potentiation (LTP) and long-term depression (LTD)—two fundamental mechanisms of synaptic plasticity—were compromised. These results demonstrate that astrocyte-mediated synapse elimination is not merely a housekeeping function, but a necessary component of functional circuit refinement during learning.

The team further investigated how astrocytes determine which synapses to remove and identified two major regulatory signals. First, increasing neuronal activity between the motor cortex and the striatum significantly enhanced astrocyte-mediated synaptic elimination (a process in which astrocytes engulf and remove synapses), indicating that circuit engagement promotes remodeling. Second, manipulating dopamine levels, a key neuromodulator for movement and reward, also strongly influenced astrocytic synapse elimination. ScienceMission sciencenewshighlights.

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When we learn a new motor skill—whether mastering a piano passage or refining balance while walking—the brain must reorganize the circuits that control movement. For decades, this process of synaptic remodeling has been attributed primarily to neurons strengthening or weakening their connections. However, the new study reveals that another cell type in the brain called astrocytes actively participates in this rewiring process.

A research team has demonstrated that astrocytes actively eliminate synapses in the striatum, a brain region that plays a central role in controlling voluntary movement and learning. This process is regulated by dopamine signaling and neural activity and is critical for proper motor skill acquisition.

Although synapse formation and elimination have long been studied in the context of neuronal plasticity, increasing evidence suggests that glial cells—particularly astrocytes and microglia—also contribute to synapse turnover. Until now, however, the precise role of astrocytes in motor learning and the mechanisms underlying their synaptic remodeling remained unclear.

The nature of human experience, or consciousness, has divided thinkers for centuries. The Scottish philosopher Hume saw experience as nothing more than a bundle of perceptions, and denied the existence of a self holding them all together. Kant disagreed, arguing that sensation had to be organised by concepts for there to be experience. It is a debate that has echoed through the Western tradition. You might think science would have settled the matter, but the same dispute is still present amongst neuroscientists. Some argue that sensation is independent of how we think, a neutral bedrock of data which enables us to experience reality. While others claim what we take to be reality is an illusion created by our brain. Do our thoughts and concepts shape and structure experience and what we take to be reality? Are current theories of neuroscience taking sides in this deeper underlying philosophical dispute? Does the existence of the self and the nature of reality depend on our philosophical outlook, or is there a fact of the matter that we might uncover?

From the article:

“A review of brain imaging studies found that handwriting activates a broader network of neural pathways than typing or tapping, engaging fine motor skills, memory encoding, and deeper cognitive processing simultaneously. The physical act of forming letters on paper recruits brain regions that digital input simply doesn’t reach. Studies suggest that the pen engages what some researchers describe as a “symphony of neural pathways,” connecting motor control to thought formation in ways that keyboards and touchscreens may bypass.”