Decreased dendritic spine density in the cortex is a hallmark of several neuropsychiatric diseases, and the ability to promote cortical neuron growth has been hypothesized to underlie the rapid and sustained therapeutic effects of psychedelics. Activation of 5-hydroxytryptamine (serotonin) 2A receptors (5-HT2ARs) is essential for psychedelic-induced cortical plasticity, but it is currently...
Since the discovery of rapid eye movement (REM) sleep, the nature of the eye movements that characterize this sleep phase has remained elusive. Do they reveal gaze shifts in the virtual environment of dreams or simply reflect random brainstem activity? We harnessed the head direction (HD) system of the mouse thalamus, a neuronal population whose activity reports, in awake mice, their actual HD...
Drugs that target the human serotonin 2A receptor (5-HT 2A R) are used to treat neuropsychiatric diseases; however, many have hallucinogenic effects, hampering their use. Here, we present structures of 5-HT 2A R complexed with the psychedelic drugs psilocin (the active metabolite of psilocybin) and d -lysergic acid diethylamide (LSD), as well as the endogenous neurotransmitter serotonin and the...
Championing open science, an adversarial collaboration aims to unravel the footprints of consciousness The history of science includes numerous challenging problems, including the “hard problem” (1) of consciousness: Why does an assembly of neurons—no matter how complex, such as the human brain—give rise to perceptions and feelings that are consciously experienced, such as the sweetness of...
ScienceSeptember 25, 2020A. Nieder, Lysann Wagener, Paul Rinnert
Consciousness shared Humans have tended to believe that we are the only species to possess certain traits, behaviors, or abilities, especially with regard to cognition. Occasionally, we extend such traits to primates or other mammals—species with which we share fundamental brain similarities. Over time, more and more of these supposed pillars of human exceptionalism have fallen. Nieder et al....
ScienceApril 12, 2019R. N. Moda-Sava, Mitchell H. Murdock, Puja K Parekh et al.
Why is ketamine an antidepressant? A better understanding of the mechanisms underlying the action of antidepressants is urgently needed. Moda-Sava et al. explored a possible mode of action for the drug ketamine, which has recently been shown to help patients recover from depression (see the Perspective by Beyeler). Ketamine rescued behavior in mice that was associated with depression-like...
In their Review “What is consciousness, and could machines have it?” (27 October 2017, p. [486][1]), S. Dehaene et al. argue that the science of consciousness indicates that we are not on the verge of creating conscious machines. However, Dehaene et al. ask and answer the wrong questions. To
In their Review “What is consciousness, and could machines have it?” (27 October 2017, p. [486][1]), S. Dehaene et al. suggest that machine consciousness, which would model human cognitive functions within a physical architecture other than the human brain, has not yet been achieved. Creating
The controversial question of whether machines may ever be conscious must be based on a careful consideration of how consciousness arises in the only physical system that undoubtedly possesses it: the human brain. We suggest that the word “consciousness” conflates two different types of information-processing computations in the brain: the selection of information for global broadcasting, thus...
![Figure][1] From consciousness to how we apprehend space and time, the mysteries of the brain—and the best ways to probe them—continue to challenge neuroscientists. ILLUSTRATION: CRISTIANA COUCEIRO Every year, tens of thousands of researchers gather for the Society for Neuroscience meeting. The lecture theaters and poster halls are full of smart and hardworking individuals. Every year, we...
ScienceMarch 31, 2017S. Sheikhbahaei, Jeffrey C. Smith
A small population of brainstem neurons connects breathing behavior to brain arousal. Breathing is one of the perpetual rhythms of life that is often taken for granted, its apparent simplicity belying the complex neural machinery involved. This behavior is more complicated than just producing inspiration, as breathing is integrated with many other motor functions such as vocalization, orofacial...
Dissecting Serotonin Receptors Serotonin receptors are the targets for many widely used drugs prescribed to treat ailments from depression to obesity and migraine headaches (see the Perspective by Palczewski and Kiser ). C. Wang et al. (p. 610 , published online 21 March) and Wacker et al. (p. 615 , published online 21 March) describe crystal structures of two members of the serotonin family of...
Dissecting Serotonin Receptors Serotonin receptors are the targets for many widely used drugs prescribed to treat ailments from depression to obesity and migraine headaches (see the Perspective by Palczewski and Kiser ). C. Wang et al. (p. 610 , published online 21 March) and Wacker et al. (p. 615 , published online 21 March) describe crystal structures of two members of the serotonin family of...
Basic and clinical studies demonstrate that depression is associated with reduced size of brain regions that regulate mood and cognition, including the prefrontal cortex and the hippocampus, and decreased neuronal synapses in these areas. Antidepressants can block or reverse these neuronal deficits, although typical antidepressants have limited efficacy and delayed response times of weeks to...
Frontoparietal cortex is involved in the explicit processing (awareness) of stimuli. Frontoparietal activation has also been found in studies of subliminal stimulus processing. We hypothesized that an impairment of top-down processes, involved in recurrent neuronal message-passing and the generation of long-latency electrophysiological responses, might provide a more reliable correlate of...
Salvia divinorum may be this generation's answer to magic mushrooms. A hallucinogenic member of the mint family, it has been used for centuries by Mexican shamans for spiritual purposes. Within the past decade it's become popular as a legal high—at least where its use hasn't been outlawed. Now researchers at Johns Hopkins University have conducted the first human laboratory study on the plant,...
The ability to introspect about self-performance is key to human subjective experience, but the neuroanatomical basis of this ability is unknown. Such accurate introspection requires discriminating correct decisions from incorrect ones, a capacity that varies substantially across individuals. We dissociated variation in introspective ability from objective performance in a simple...