Proceedings of the National Academy of Sciences of the United States of America
July 16, 2021
Josef Parvizi, Rodrigo M. Braga, Aaron Kucyi et al.
59 citations
Significance In this manuscript, we report a rare case of a patient with localized seizures originating from the right anterior and dorsal posteromedial cortex (PMC). We mapped the electrophysiological and neuroimaging connectivity of the ictal onset site and replicated seizure auras by stimulating the homotopical PMC site in the left hemisphere. Our findings provide a causal link between PMC...
Proceedings of the National Academy of Sciences of the United States of America
June 30, 2021
L. Stiernman, F. Grill, A. Hahn et al.
Significance A consistent finding from functional MRI (fMRI) of externally focused cognitive control is negative signal change in the brain’s default mode network (DMN), but it is unknown whether this reflects an increase of synaptic activity during rest periods or active suppression during task. Using hybrid PET-MRI, we show that task-positive fMRI responses align with increasing glucose...
Proceedings of the National Academy of Sciences of the United States of America
June 11, 2021
K. Clancy, Jeremy A. Andrzejewski, Yuqi You et al.
Significance In the brain’s functional organization, the default mode network (DMN) represents a key architecture, whose dysregulation is involved in a host of major neuropsychiatric disorders. However, insights into the regulation of the DMN remain scarce. Through neural synchrony, the alpha-frequency oscillation represents another key underpinning of the brain’s organization and is thought to...
Proceedings of the National Academy of Sciences of the United States of America
December 8, 2020
David W Robinson, Kelly Brown, Moira Mcmenemy et al.
40 citations
While debates have raged over the relationship between trance and rock art, unambiguous evidence of the consumption of hallucinogens has not been reported from any rock art site in the world. A painting possibly representing the flowers of Datura on the ceiling of a Californian rock art site called Pinwheel Cave was discovered alongside fibrous quids in the same ceiling. Even though Native...
Proceedings of the National Academy of Sciences of the United States of America
June 15, 2020
J. Ferrier, E. Tiran, T. Deffieux et al.
Significance Our report first validates an imaging technique, functional ultrasound, an experimental approach providing significantly higher sensitivity and spatiotemporal resolution than fMRI, for the study of sensory stimulation-induced changes in activation and connectivity patterns in the awake mouse brain. Next, by using this approach in lightly sedated conscious mice, we provide...
Proceedings of the National Academy of Sciences of the United States of America
March 31, 2020
Gaëtan Sanchez, Thomas Hartmann, Marco Fuscà et al.
An increasing number of studies highlight common brain regions and processes in mediating conscious sensory experience. While most studies have been performed in the visual modality, it is implicitly assumed that similar processes are involved in other sensory modalities. However, the existence of supramodal neural processes related to conscious perception has not been convincingly shown so...
Proceedings of the National Academy of Sciences of the United States of America
January 15, 2020
Matthew E. Klein, Joshua Chandra, Salma A. Sheriff et al.
157 citations
Significance Ketamine, an NMDA receptor antagonist, has generated intense excitement as a therapy for treatment-resistant depression. However, ketamine and its metabolites can act on a wide range of targets, including opioid receptors, which has raised concerns. Using behavioral and cellular assays in rodents, we find that blocking opioid function prevents the antidepressant-like effects of...
Proceedings of the National Academy of Sciences of the United States of America
June 4, 2019
Melanie J Miller, Juan Albarracin-Jordan, Christine K. Moore et al.
171 citations
Over several millennia, various native plant species in South America have been used for their healing and psychoactive properties. Chemical analysis of archaeological artifacts provides an opportunity to study the use of psychoactive plants in the past and to better understand ancient botanical knowledge systems. Liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to analyze...
Proceedings of the National Academy of Sciences of the United States of America
May 21, 2019
Christine S. Vanpool
Many archaeologists suggest that shamanic practices are ancient, starting at least 30,000 y ago (1⇓–3). As an analytical concept, anthropologists define shamans as religious practitioners who interact directly with the spirit world to help their people. Shamans in each culture have their own practices and are called by different names (e.g., chayanyi , curanderos , or vegetalistas ). Shamanic...
Proceedings of the National Academy of Sciences of the United States of America
March 12, 2019
Marian Schneider, Valentin G Kemper, Thomas C Emmerling et al.
The specific contents of human consciousness rely on the activity of specialized neurons in cerebral cortex. We hypothesized that the conscious experience of a specific visual motion axis is reflected in response amplitudes of direction-selective clusters in the human motion complex. Using submillimeter fMRI at ultrahigh field (7 T) we identified fine-grained clusters that were tuned to either...
Proceedings of the National Academy of Sciences of the United States of America
February 22, 2019
E. Lumsden, Timothy A. Troppoli, S. J. Myers et al.
159 citations
Significance Standard antidepressant treatments require weeks to show effectiveness. A single subanesthetic dose of ketamine rapidly attenuates many clinical signs and symptoms of depression; however, ketamine treatment also has many adverse effects, including dissociation and potential for abuse, which are mediated by NMDA glutamate receptor (NMDAR) inhibition. Previous work has revealed that...
Proceedings of the National Academy of Sciences of the United States of America
February 11, 2019
Emily K. Lindsay, S. Young, K. Brown et al.
Significance Loneliness (i.e., feeling alone) and social isolation (i.e., being alone) are among the most robust known risk factors for poor health and accelerated mortality. Yet mitigating these social risk factors is challenging, as few interventions have been effective for both reducing loneliness and increasing social contact. Mindfulness interventions, which train skills in monitoring...
Proceedings of the National Academy of Sciences of the United States of America
2019
Archaeological studies have found evidence of ritual consumption of psychoactive plants among native cultures in South America. However, the evidence is fragmentary, preventing researchers from piecing together a coherent picture of hallucinogen use in ancient South America. Melanie Miller et al. (pp. 11207–11212) analyzed the chemical makeup of artifacts in a 1,000-year-old ritual bundle...
Proceedings of the National Academy of Sciences of the United States of America
September 17, 2018
Yoona Kang, Nicole Cooper, Prateekshit Pandey et al.
Significance People often feel defensive when reminded of their unhealthy behavior. We propose that self-transcendence, encouraged by focusing on others’ well-being, can lessen subsequent focus on threatened aspects of the self and increase receptivity. We show that activating self-transcendent mindsets, either by reflecting on self-transcendent values or making positive wishes for others,...
Proceedings of the National Academy of Sciences of the United States of America
September 11, 2018
Lauri Nummenmaa, Riitta Hari, Jari K Hietanen et al.
Subjective feelings are a central feature of human life. We defined the organization and determinants of a feeling space involving 100 core feelings that ranged from cognitive and affective processes to somatic sensations and common illnesses. The feeling space was determined by a combination of basic dimension rating, similarity mapping, bodily sensation mapping, and neuroimaging...
Proceedings of the National Academy of Sciences of the United States of America
April 4, 2017
Johannes J Fahrenfort, Jonathan Van Leeuwen, Christian N L Olivers et al.
102 citations
The visual system has the remarkable ability to integrate fragmentary visual input into a perceptually organized collection of surfaces and objects, a process we refer to as perceptual integration. Despite a long tradition of perception research, it is not known whether access to consciousness is required to complete perceptual integration. To investigate this question, we manipulated access to...
Proceedings of the National Academy of Sciences of the United States of America
May 17, 2016
Yuan-Wei Zhang, Benjamin E Turk, Gary Rudnick
53 citations
Serotonin transporter (SERT) is responsible for reuptake and recycling of 5-hydroxytryptamine (5-HT; serotonin) after its exocytotic release during neurotransmission. Mutations in human SERT are associated with psychiatric disorders and autism. Some of these mutations affect the regulation of SERT activity by cGMP-dependent phosphorylation. Here we provide direct evidence that this...
Proceedings of the National Academy of Sciences of the United States of America
October 15, 2015
Masafumi Oizumi, Naotsugu Tsuchiya, S. Amari
Significance Measuring the degree of causal influences among multiple elements of a system is a fundamental problem in physics and biology. We propose a unified framework for quantifying any combination of causal relationships between elements in a hierarchical manner based on information geometry. Our measure of integration, called geometrical integrated information, quantifies the strength of...
Proceedings of the National Academy of Sciences of the United States of America
April 21, 2015
Aaron Schurger, Ioannis Sarigiannidis, Lionel Naccache et al.
According to recent evidence, stimulus-tuned neurons in the cerebral cortex exhibit reduced variability in firing rate across trials, after the onset of a stimulus. However, in order for a reduction in variability to be directly relevant to perception and behavior, it must be realized within trial--the pattern of activity must be relatively stable. Stability is characteristic of decision states...
Proceedings of the National Academy of Sciences of the United States of America
March 25, 2014
Loretxu Bergouignan, Lars Nyberg, H Henrik Ehrsson
Theoretical models have suggested an association between the ongoing experience of the world from the perspective of one's own body and hippocampus-based episodic memory. This link has been supported by clinical reports of long-term episodic memory impairments in psychiatric conditions with dissociative symptoms, in which individuals feel detached from themselves as if having an out-of-body...
Proceedings of the National Academy of Sciences of the United States of America
August 27, 2013
Jimo Borjigin, UnCheol Lee, Tiecheng Liu et al.
The brain is assumed to be hypoactive during cardiac arrest. However, the neurophysiological state of the brain immediately following cardiac arrest has not been systematically investigated. In this study, we performed continuous electroencephalography in rats undergoing experimental cardiac arrest and analyzed changes in power density, coherence, directed connectivity, and cross-frequency...
Proceedings of the National Academy of Sciences of the United States of America
June 18, 2013
John R Searle
We do not have an adequate theory of consciousness. Both dualism and materialism are mistaken because they deny consciousness is part of the physical world. False claims include (i) behaviorism, (ii) computationalism, (iii) epiphenomenalism, (iv) the readiness potential, (v) subjectivity, and (vi) materialism. Ontological subjectivity does not preclude epistemic objectivity. Observer relative...
Proceedings of the National Academy of Sciences of the United States of America
June 18, 2013
Ho Ming Chow, Silvina G. Horovitz, Walter S. Carr et al.
Rapid eye movement (REM) sleep constitutes a distinct "third state" of consciousness, during which levels of brain activity are commensurate with wakefulness, but conscious awareness is radically transformed. To characterize the temporal and spatial features of this paradoxical state, we examined functional interactions between brain regions using fMRI resting-state connectivity methods....
Proceedings of the National Academy of Sciences of the United States of America
June 26, 2012
Yi-Yuan Tang, Qilin Lu, Ming Fan et al.
Using diffusion tensor imaging, several recent studies have shown that training results in changes in white matter efficiency as measured by fractional anisotropy (FA). In our work, we found that a form of mindfulness meditation, integrative body-mind training (IBMT), improved FA in areas surrounding the anterior cingulate cortex after 4-wk training more than controls given relaxation training....
Proceedings of the National Academy of Sciences of the United States of America
February 15, 2011
Mohammad Dastjerdi, Brett L Foster, Sharmin Nasrullah et al.
The electrophysiological basis for higher brain activity during rest and internally directed cognition within the human default mode network (DMN) remains largely unknown. Here we use intracranial recordings in the human posteromedial cortex (PMC), a core node within the DMN, during conditions of cued rest, autobiographical judgments, and arithmetic processing. We found a heterogeneous profile...