Vision/Visual Processing

Glutamate/GABA balance in visual perception. As we know, glutamate and GABA have a relationship similar to a seesaw, when glutamate is high, GABA is low. “During the trials, the researchers also used magnetic resonance imaging and spectra (MRI and MRS) techniques to measure GABA concentrations in the visual cortex of each participant. In neurotypicals, as GABA concentrations increased in the visual cortex, so did perceptual suppression. However, in participants with autism, there was no relationship between GABA concentration and perceptual suppression, which could indicate that GABA plays a reduced role in binocular rivalry in individuals with autism, or that GABA-related circuitry generates insufficient suppression even when GABA itself is present. The MRI/MRS also measured glutamate, an excitatory neurotransmitter that acts in opposition to GABA, and several other molecules as controls. Glutamate levels did correlate with perceptual suppression in both neurotypicals and participants with autism. No other molecules the researchers measured correlated with perceptual suppression in either neurotypicals or individuals with autism.”


“Excitatory amino acids, glutamate in particular, have a marked stimulatory effect on the reproductive axis, particularly at puberty. Glutamate, N-methyl-D-aspartate (NMDA), and kainate stimulate gonadotropin-releasing hormone (GnRH) secretion in immature mammals and NMDA receptor stimulation results in precocious puberty in rats and monkeys.”

“The excitatory amino acid glutamate and especially its NMDA subtype receptor are important components of the neural system that regulates sexual maturation. It is known that multiple daily injections of immature rats and monkeys with NMDA will induce precocious puberty.”