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Volterra and colleagues report that activation of the chemokine receptor CXCR4 evokes TNFalpha release, leading to glutamate release from astrocytes. The pathway can be amplified and become neurotoxic via release of TNFalpha from reactive microglia, and the HIV coat protein gp120 can also bind CXCR4 to activate the pathway. Confocal image shows expression of TNFalpha (pink) at the membrane surface of GFAP-positive astrocytes (blue) and ILB4-positive microglia (yellow). See pages 676 and 702.
In peripheral vision, individual item information becomes inaccessible in the presence of distractors. Parkes et al. now show this information is not lost, but integrated into accurate ensemble statistics, suggesting that such 'crowding' may be related to texture perception.
GABA is inhibitory in adults, but it is excitatory in young animals. A recent study shows that activation of the GABAA receptor itself may promote this developmental switch.
Chemokine signaling releases glutamate from astrocytes. This process can be amplified by microglia, inducing neurotoxicity, and activated by the HIV coat protein gp120.
A new study reports unconscious activation of occipital and frontal cortex by masked visual stimuli, showing that activity in these areas may be insufficient for awareness