Local GABA Concentration Predicts Perceptual Improvements After Repetitive Sensory Stimulation in Humans.

Learning mechanisms are based on synaptic plasticity processes. Numerous studies on synaptic plasticity suggest that the regulation of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) plays a central role maintaining the delicate balance of inhibition and excitation. However, in humans, a link between learning outcome and GABA levels has not been shown so far.

The brain's dress code: How The Dress allows to decode the neuronal pathway of an optical illusion.

Optical illusions have broadened our understanding of the brain's role in visual perception. A modern day optical illusion emerged from a posted photo of a striped dress, which some perceived as white and gold and others as blue and black. Here we show, using functional magnetic resonance imaging (fMRI), that those who perceive The Dress as white/gold have higher activation in response to the image of The Dress in brain regions critically involved in higher cognition (frontal and parietal brain areas).

From perceptual to lexico-semantic analysis--cortical plasticity enabling new levels of processing.

Certain kinds of stimuli can be processed on multiple levels. While the neural correlates of different levels of processing (LOPs) have been investigated to some extent, most of the studies involve skills and/or knowledge already present when performing the task. In this study we specifically sought to identify neural correlates of an evolving skill that allows the transition from perceptual to a lexico-semantic stimulus analysis.

Resting BOLD fluctuations in the primary somatosensory cortex correlate with tactile acuity.

Sensory perception, including 2-point discrimination (2 ptD), is tightly linked to cortical processing of tactile stimuli in primary somatosensory cortices. While the role of cortical activity in response to a tactile stimulus has been widely investigated, the role of baseline cortical activity is largely unknown. Using resting state fMRI we investigated the relationship between local BOLD fluctuations in the primary somatosensory cortex (the representational field of the hand) and 2 ptD of the corresponding index finger (right and left).

Comparison of the effects of ketamine, ketamine-medetomidine, and ketamine-midazolam on physiologic parameters and anesthesia-induced stress in rhesus (Macaca mulatta) and cynomolgus (Macaca fascicularis) macaques.

This study compared the cardiovascular, respiratory, anesthetic, and glucocorticoid effects of ketamine alone with ketamine-medetomidine and ketamine-midazolam in rhesus and cynomolgus macaques. Macaques were given either intramuscular ketamine (10 mg/kg), intramuscular ketamine-medetomidine (3 mg/kg; 0.15 mg/kg), or oral midazolam (1 mg/kg) followed by intramuscular ketamine (8 mg/kg).