Neural Noise- MIT researchers showed that astrocytes help maintain neural information processing in vision by maintaining ambient levels of the neurotransmitter GABA.1
- The work used a novel application of tools and analysis to link non-neural brain cells to visual processing; relevant to computational neuroscience and neural information processing (tier-2 for mechanisms; no devices or trials).1 1
Weekly enrichment (2026-07-20)
- The peer-reviewed paper is Park et al., “Astrocytic modulation of population encoding in mouse visual cortex via GABA transporter 3 revealed by multiplexed CRISPR/Cas9 gene editing,” published in eLife (2025; DOI 10.7554/eLife.107298), from Mriganka Sur’s lab at MIT’s Picower Institute with first author Jiho Park.2 3
- Gat3 (encoded by the gene Slc6a11) is an astrocyte-specific GABA transporter that maintains ambient, extra-synaptic levels of the inhibitory neurotransmitter GABA in the cortex.2 3
- To delete it, the team built a multiplexed CRISPR/Cas9 tool called MRCUTS (Multiple sgRNA Csy4-mediated Universal Targeting System), packaging six guide RNAs against Slc6a11 into a single AAV vector (separated by Csy4 cut sites) delivered into Cas9-expressing mice for spatially and temporally selective knockout in visual cortex astrocytes.3 4
- Neuronal activity was read out with in vivo two-photon calcium imaging in the mouse visual cortex during natural movie viewing, capturing both single-neuron and population-level responses.2 3
- After Gat3 knockout, individual neurons still fired but did so less robustly and less reliably, and spontaneous activity during a gray screen decreased; orientation tuning (orientation selectivity index) of single neurons was largely preserved.2 4
- The deficit emerged at the population level: using a Generalized Linear Model, the activity of each neuron became less predictive of others in the ensemble, indicating impaired coordination.2
- Using a Support Vector Machine decoder, adding more neurons improved stimulus decoding when Gat3 was intact, but with Gat3 knocked out the decoder failed to improve even as sample size grew — evidence that astrocytic control of ambient GABA is needed for efficient population encoding.2 4
- The authors note this is the first in vivo study of Gat3 spanning single cells to ensembles of hundreds of neurons, and link it to clinical observations that Gat3 reduction in the thalamus raises seizure risk, its increase in the striatum contributes to repetitive behaviors, and its reduction in the globus pallidus impairs motor coordination; funding included the NIH, a MURI grant, and the Simons Foundation Autism Research Initiative.2 3