On some days, time flies by, while on others it seems to drag on. A new study from JNeurosci reveals why: time-sensitive neurons get worn out and skew our perceptions of time.
Neurons in the supramarginal gyrus (SMG) fire in response to a specific length of time. If repeatedly exposed to a stimulus of a fixed duration, the neurons fatigue. Since other neurons continue firing normally, our subjective perception of time becomes skewed.
Hayashi and Ivry measured brain activity with fMRI as human participants engaged in a time comparison task. Healthy adult participants viewed a visual adaptor (a grey circle) for a set length of time, 30 times in a row. After this adaptation period, they were shown a test stimulus and indicated its duration. If the adaptor duration was long, the participants underestimated time; if the adaptor duration was short, they overestimated time. Activity in the SMG decreased when the adaptor and test stimulus were similar in length, indicating neuron fatigue. The extent of skewed time perception correlated with how much the activity in the SMG decreased -- greater fatigue led to greater time distortion.
Manuscript title: Duration-Selectivity in Right Parietal Cortex Reflects the Subjective Experience of Time
JNeurosci, the Society for Neuroscience's first journal, was launched in 1981 as a means to communicate the findings of the highest quality neuroscience research to the growing field. Today, the journal remains committed to publishing cutting-edge neuroscience that will have an immediate and lasting scientific impact, while responding to authors' changing publishing needs, representing breadth of the field and diversity in authorship.
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The Society for Neuroscience is the world's largest organization of scientists and physicians devoted to understanding the brain and nervous system. The nonprofit organization, founded in 1969, now has nearly 37,000 members in more than 90 countries and over 130 chapters worldwide.