Neuronal rigidity in Autism: Understanding a new path to flexibility

Autism manifests in many different ways. While social challenges and sensory sensitivity are frequently highlighted, another dimension plays a central role: difficulty adapting to change. Many autistic individuals struggle to shift from one activity to another, to adjust their strategies when the environment evolves or to modify their responses in the face of the unexpected.

Researchers refer to this ability as cognitive flexibility, which depends on an invisible but essential mechanism: the brain’s capacity to transition from one state of activity to another. A helpful way to visualize this is to imagine the brain as a machine with multiple configurations. Moving from mode A to mode B requires extra energy, much like transforming a sofa into a bed. The basic structure remains the same, but switching its function demands additional effort. In autistic individuals, this energy needed for transition seems less accessible, which may explain the tendency to remain locked into an activity, to repeat certain behaviors or to struggle when adjusting to new situations.

Revealing how the Autistic brain navigates internal states

To better understand this phenomenon, neuroscientists used a mathematical tool known as energy landscape analysis. The idea is to represent brain states as valleys separated by hills. The deeper the valley, the more the brain tends to remain stuck there. The higher the hill, the harder it becomes to transition to another state. When comparing autistic and neurotypical adults, researchers found that autistic individuals remained longer in certain brain states, illustrating a form of neuronal rigidity.

This rigidity does not arise from a single region but from the brain’s overall organization. Communication networks connecting frontal, parietal, visual and sensory areas appear less flexible, which limits the fluidity of brain activity. These findings offer a concrete scientific framework that mirrors the cognitive inflexibility observed at the behavioral level.

How targeted brain stimulation unlocks cognitive flexibility

To counter this rigidity, a Japanese research team used a non-invasive technique already employed in psychiatry and neurology: transcranial magnetic stimulation. Their goal was to apply small magnetic pulses at the right moment to a key brain region, the right superior parietal lobule, which is involved in attention control and information integration. By precisely targeting this area, the researchers were able to strengthen the functioning of a brain network known as the frontoparietal network, which plays a central role in coordinating activity across different brain regions. Thanks to this targeted stimulation, transitions from one neural state to another occurred more easily, and participants showed improved ability to alternate between two tasks performed simultaneously.

This improvement, observable from the first session, highlights the potential of the approach. Cognitive inflexibility, long viewed as a core and immovable characteristic of autism, emerges here as a partially modifiable phenomenon. Early results indicate enhanced task-switching abilities, reflected in shorter response times and greater cognitive flexibility. In other words, brain rigidity, measured both through neural states and through behavior, can be softened.

Brain imaging results support these observations. After stimulation, the interactions between major brain networks, such as the frontoparietal network associated with cognitive control, the salience network involved in detecting relevant stimuli, the visual network and the default mode network linked to internal thought, appeared more balanced. It is as if stimulation helped orchestrate these neural ensembles more effectively, restoring a degree of flexibility the brain previously lacked. Although these improvements remain modest and require confirmation, they suggest that stimulation may influence aspects of daily functioning in a meaningful way.

However, researchers remain cautious. The effects are temporary and tend to diminish after a few weeks. To prolong the benefits, protocols must be refined by testing repeated or closer-spaced sessions or adapting intensity. Clinical application will only be possible once results are confirmed in larger and more diverse groups.

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Rethinking Autism through the lens of brain plasticity

These findings open an encouraging path by suggesting that cognitive inflexibility, long perceived as a fixed trait, can be modulated through targeted interventions. Brain stimulation is not a miracle cure and is not intended to “correct” autism, but rather to reduce certain difficulties that affect daily life, particularly behavioral rigidity. Clinical translation will require refining protocols, evaluating long-term effects and ensuring the absence of adverse consequences.

Nonetheless, the discovery that neuronal rigidity can be softened, even temporarily, alters the way we conceptualize autism. It shows that certain characteristics, long considered immutable, can be influenced by precise, well-timed interventions. This advancement is not a definitive answer, but it opens an important perspective: instead of viewing inflexibility as unavoidable, we can now consider it a dynamic phenomenon that science is beginning to understand and modulate.