Once Thought to Support Neurons, Astrocytes Turn Out to Be in Charge
3 days ago
- #neuromodulation
- #astrocytes
- #neuroscience
- Astrocytes, once considered mere support cells for neurons, are now recognized as key regulators of brain circuits and overall brain state.
- Recent studies in mice, zebra fish, and fruit flies show astrocytes influence neuromodulation, affecting behaviors like alertness, anxiety, and apathy.
- Astrocytes outnumber neurons in many brain regions and can envelop millions of synapses, positioning them to significantly impact information flow.
- Astrocytes do not engage in rapid signaling like neurons but monitor and adjust network activity over longer timescales (seconds to minutes).
- Norepinephrine triggers astrocyte activity, linking them to neuromodulation and behavioral state changes, such as startle responses or giving up.
- In zebra fish, disabling astrocytes prevented them from giving up in a swimming task, while activating astrocytes made them stop immediately.
- Parallel findings in fruit flies, zebra fish, and mice suggest astrocytes' role in neuromodulation is evolutionarily conserved.
- Astrocytes may be involved in sleep, psychiatric disorders, and mood regulation, offering new targets for treating brain disorders.
- Current neuroscience models often overlook astrocytes, despite their profound influence on neural circuit function.