eNeuro
March 1, 2016
Victoria Phoumthipphavong, Florent Barthas, Samantha Hassett et al.
142 citations
A single low dose of ketamine, an NMDA receptor antagonist, produces fast-acting antidepressant effects. In mice, a single injection of ketamine increased dendritic spine density in the medial frontal cortex for up to two weeks compared to saline-injected controls. This prolonged increase was driven by a higher rate of new spine formation, not by changes in spine elimination. Some new spines persisted, indicating functional synapses. In a few cases, distal apical tuft branches retracted the day after ketamine administration. These findings suggest that ketamine causes immediate removal of some dendritic inputs and gradual addition of others, consistent with a rebalancing of synaptic inputs onto frontal cortical neurons.
eNeuro
August 1, 2024
Sana Khan, Yixiang Huang, Derin Timuçin et al.
23 citations
Volatile anesthetics like isoflurane may cause unconsciousness by binding to microtubules (MTs) inside neurons and dampening their quantum optical effects. In male rats injected with the MT-stabilizing drug epothilone B (epoB), loss of righting reflex under 4% isoflurane took an average of 69 seconds longer than in rats given a placebo. The difference was statistically significant with a large effect size (Cohen's d = 1.9) and could not be explained by tolerance from repeated anesthetic exposure. This supports the idea that consciousness arises from quantum physical states in neural microtubules, as proposed in the orchestrated objective reduction (Orch OR) theory.
eNeuro
October 1, 2025
Tanner L. Anderson, Artin Asadipooya, Pavel I. Ortinski
3 citations
Psychedelic drugs like DOI can reverse the direction of synaptic plasticity in the claustrum, a brain region rich in serotonin 2 receptors and heavily connected to the anterior cingulate cortex. In male rats, pairing presynaptic stimuli with postsynaptic action potentials in claustrum neurons projecting to the ACC caused DOI to flip the plasticity from long-term depression to long-term potentiation, an effect specific to locally activated synapses. DOI also altered several action potential dynamics in these neurons. The findings support the idea that psychedelics induce rapid and lasting neuroplasticity and that claustrocortical circuits are especially sensitive to these drugs, offering a potential mechanism for their therapeutic effects.
eNeuro
March 1, 2025
Sarah D Jennings, Devin P Hagarty, Jordan Logue et al.
1 citation
Repeated ketamine infusions for depression may be riskier in people with a history of alcohol use, and effects differ by sex. In rats, females self-administered more ketamine than males. A history of alcohol increased ketamine intake in females, while a history of either isolation or alcohol independently increased ketamine intake in males. All groups showed similar extinction and cue-induced reinstatement. In the nucleus accumbens, isolation increased immature dendritic spines in males, an effect reduced by alcohol; alcohol increased immature spines in females. The findings suggest that prior social isolation and alcohol exposure alter ketamine's reinforcing properties in a sex-dependent manner, highlighting the need to consider sex and alcohol history when using ketamine to treat depression.
eNeuro
July 7, 2025
Andy Jeesu Kim, Keran Chen, Ying Tian et al.
Thirty days of guided mindfulness meditation using a mobile app improved the speed of saccadic eye movements (overt orienting of attention) in adults, but did not reduce distractibility or enhance goal-directed attentional control beyond repeated task practice. The benefits were similar across young, middle-aged, and older adults, and no changes appeared in self-report mindfulness questionnaires. The findings suggest that short-term mindfulness practice can modulate cognition in ways detectable by eye tracking but not by self-report, and that age does not moderate these effects.
eNeuro
January 1, 2021
Matthew S Willsey, Chrono S Nu, Samuel R Nason et al.
Inhaling 70% nitrous oxide (N2O) increases spiking rates and beta- and gamma-band power in the primary motor cortex of macaques while degrading the representation of somatosensory information. The proportion of correctly classified finger touches dropped from 0.50 to 0.34 during N2O inhalation, indicating impaired information transfer. The increased firing rate was not correlated with changes in neuronal tuning, suggesting a dissociation between overall activity and sensory processing.