9 results on '"Mears RP"'
Search Results
2. DISCUSSION ON ROAD PAPER NO. 54: THE DESIGN OF NEATH AND BRITON FERRY VIADUCTS.
- Author
-
MEARS, RP, primary, POOL, EE, additional, SKINNER, JBH, additional, SMITH, HS, additional, MANNING, GP, additional, ADAMS, HC, additional, LOWE, JR, additional, AUSTIN, WTF, additional, GELSON, WE, additional, SHIPWAY, JS, additional, and YOUNG, JM, additional
- Published
- 1957
- Full Text
- View/download PDF
3. Open science in psychophysiology: An overview of challenges and emerging solutions.
- Author
-
Garrett-Ruffin S, Hindash AC, Kaczkurkin AN, Mears RP, Morales S, Paul K, Pavlov YG, and Keil A
- Subjects
- Humans, Reproducibility of Results, Psychophysiology
- Abstract
The present review is the result of a one-day workshop on open science, held at the Annual Meeting of the Society for Psychophysiological Research in Washington, DC, September 2019. The contributors represent psychophysiological researchers at different career stages and from a wide spectrum of institutions. The state of open science in psychophysiology is discussed from different perspectives, highlighting key challenges, potential benefits, and emerging solutions that are intended to facilitate open science practices. Three domains are emphasized: data sharing, preregistration, and multi-site studies. In the context of these broader domains, we present potential implementations of specific open science procedures such as data format harmonization, power analysis, data, presentation code and analysis pipeline sharing, suitable for psychophysiological research. Practical steps are discussed that may be taken to facilitate the adoption of open science practices in psychophysiology. These steps include (1) promoting broad and accessible training in the skills needed to implement open science practices, such as collaborative research and computational reproducibility initiatives, (2) establishing mechanisms that provide practical assistance in sharing of processing pipelines, presentation code, and data in an efficient way, and (3) improving the incentive structure for open science approaches. Throughout the manuscript, we provide references and links to available resources for those interested in adopting open science practices in their research., (Copyright © 2021. Published by Elsevier B.V.)
- Published
- 2021
- Full Text
- View/download PDF
4. Altered sulcogyral patterns of orbitofrontal cortex in a large cohort of patients with schizophrenia.
- Author
-
Isomura S, Hashimoto R, Nakamura M, Hirano Y, Yamashita F, Jimbo S, Yamamori H, Fujimoto M, Yasuda Y, Mears RP, and Onitsuka T
- Abstract
Abnormalities in prenatal brain development contribute to schizophrenia vulnerability. Orbitofrontal cortex sulcogyral patterns are largely determined during prenatal development, and four types of orbitofrontal cortex sulcogyral patterns have been classified in humans. Altered orbitofrontal cortex patterns have been reported in individuals with schizophrenia using magnetic resonance imaging; however, sample sizes of previous studies were small-medium effects for detection, and gender manifestation for orbitofrontal cortex sulcogyral patterns is unclear. The present study investigated orbitofrontal cortex patterns of 155 patients with schizophrenia and 375 healthy subjects. The orbitofrontal cortex sulcogyral pattern distributions of schizophrenia were significantly different compared with healthy subjects in the left hemisphere ( χ
2 = 14.55, p = 0.002). In female schizophrenia, post-hoc analyses revealed significantly decreased Type I expression ( χ2 = 6.76, p = 0.009) and increased Type II expression ( χ2 = 11.56, p = 0.001) in the left hemisphere. The present study suggested that female schizophrenia showed altered orbitofrontal cortex patterns in the left hemisphere, which may be related to neurodevelopmental abnormality.- Published
- 2017
- Full Text
- View/download PDF
5. Electrophysiological assessment of auditory stimulus-specific plasticity in schizophrenia.
- Author
-
Mears RP and Spencer KM
- Subjects
- Adult, Analysis of Variance, Brain physiopathology, Brain Mapping methods, Evoked Potentials, Humans, Middle Aged, Task Performance and Analysis, Young Adult, Acoustic Stimulation methods, Electroencephalography methods, Evoked Potentials, Auditory, Neuronal Plasticity, Schizophrenia physiopathology
- Abstract
Background: Disrupted neuroplasticity may be an important aspect of the neural basis of schizophrenia. We used event-related brain potentials (ERPs) to assay neuroplasticity after auditory conditioning in chronic schizophrenia patients (SZ) and matched healthy control subjects (HC)., Methods: Subjects (15 HC, 14 SZ) performed an auditory oddball task during electroencephalogram recording before and after auditory tetanic stimulation (Pre/Post Blocks). Each oddball block consisted of 1000-Hz and 1500-Hz standards and 400-Hz targets. During tetanic conditioning, 1000-Hz tones were presented at 11 Hz for 2.4 min. We analyzed the standard trials, comparing the ERPs evoked by the tetanized stimuli (1000 Hz tones: TS+) and untetanized stimuli (1500 Hz tones: TS-) in the Post Blocks with ERPs from the Pre Blocks (averaged into Baseline ERPs)., Results: In Post Block 1 in HC, TS+ tones evoked a negative shift (60-350 msec) at right temporal electrodes relative to Baseline. No pre-/post-tetanus effects were found in SZ. In Post Block 2 in HC, TS+ tones evoked a positive shift (200-300 msec) at bilateral frontal electrodes. In SZ, TS+ tones evoked a positive shift (100-400 msec) at right frontotemporal electrodes. No pre-/post-tetanus effects were found in either subject group for the TS- tones. The right temporal Post Block 1 and 2 effects were correlated in SZ, suggesting a trade-off in the expression of these effects., Conclusions: These results suggest that stimulus-specific auditory neuroplasticity is abnormal in schizophrenia. The electrophysiologic assessment of stimulus-specific plasticity may yield novel targets for drug treatment in schizophrenia., (Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
6. Reduction of prelimbic inhibitory gating of auditory evoked potentials after fear conditioning.
- Author
-
Mears RP, Boutros NN, and Cromwell HC
- Subjects
- Acoustic Stimulation methods, Animals, Electroencephalography, Electroshock adverse effects, Extinction, Psychological physiology, Male, Rats, Rats, Sprague-Dawley, Reaction Time physiology, Statistics, Nonparametric, Conditioning, Classical physiology, Evoked Potentials, Auditory physiology, Fear, Neural Inhibition physiology, Prefrontal Cortex physiology, Sensory Gating physiology
- Abstract
Inhibitory gating (IG) is a basic central nervous system process for filtering repetitive sensory information. Although IG deficits coincide with cognitive and emotional dysfunction in a variety of neuropsychiatric disorders, limited research has been completed on the basic, functional nature of IG. Persistent IG occurs in rat prelimbic medial prefrontal cortex (mPFC), a crucial site for modulating emotional learning. To investigate the interaction of affect and IG, we recorded local field potentials (LFP) directly from prelimbic mPFC and examined the influence of tone-shock fear conditioning (FC) on IG. Behavioral reactions during IG were observed before and after FC, and increase of orienting response after FC indicated induction of tone-shock association. After FC, some components of LFP response exhibited short-term weakening of IG. On a subsequent day of recording, IG strengthened for all LFP components, but individual components differed in their particular changes. Affective regulation of IG represents an important factor influencing within-subject IG variability, and these results have implications for understanding the role of rapid, implicit neural coding involved in emotional learning and affective disruption in psychiatric disease., ((c) 2009 APA, all rights reserved.)
- Published
- 2009
- Full Text
- View/download PDF
7. Sensory gating: a translational effort from basic to clinical science.
- Author
-
Cromwell HC, Mears RP, Wan L, and Boutros NN
- Subjects
- Acoustic Stimulation, Animals, Habituation, Psychophysiologic physiology, Humans, Psychoacoustics, Rats, Evoked Potentials, Auditory physiology, Schizophrenia physiopathology, Schizophrenic Psychology, Sensory Thresholds physiology, Signal Processing, Computer-Assisted
- Abstract
Sensory gating (SG) is a prevalent physiological process important for information filtering in complex systems. SG is evaluated by presenting repetitious stimuli and measuring the degree of neural inhibition that occurs. SG has been found to be impaired in several psychiatric disorders. Recent animal and human research has made great progress in the study of SG, and in this review we provide an overview of recent research on SG using different methods. Animal research has uncovered findings that suggest (1) SG is displayed by single neurons and can be similar to SG observed from scalp recordings in humans, (2) SG is found in numerous brain structures located in sensory, motor and limbic subregions, (3) SG can be significantly influenced by state changes of the organism, and (4) SG has a diverse pharmacological profile accented by a strong influence from nicotine receptor activation. Human research has addressed similar issues using deep electrode recordings of brain structures. These experiments have revealed that (1) SG can be found in cortical regions surrounding hippocampus, (2) the order of neural processing places hippocampal involvement during a later stage of sensory processing than originally thought, and (3) multiple subtypes of gating exist that could be dependent on different brain circuits and more or less influenced by alterations in organismal state. Animal and human research both have limitations. We emphasize the need for integrative approaches to understand the process and combine information between basic and clinical fields so that a more complete picture of SG will emerge.
- Published
- 2008
- Full Text
- View/download PDF
8. Single unit and population responses during inhibitory gating of striatal activity in freely moving rats.
- Author
-
Cromwell HC, Klein A, and Mears RP
- Subjects
- Acoustic Stimulation methods, Analysis of Variance, Animals, Behavior, Animal, Brain Mapping, Corpus Striatum cytology, Food Deprivation physiology, Male, Movement physiology, Rats, Rats, Sprague-Dawley, Reaction Time physiology, Reflex, Startle physiology, Wakefulness physiology, Action Potentials physiology, Corpus Striatum physiology, Evoked Potentials, Auditory physiology, Neural Inhibition physiology, Neurons physiology
- Abstract
The striatum is thought to be an essential region for integrating diverse information in the brain. Rapid inhibitory gating (IG) of sensory input is most likely an early factor necessary for appropriate integration to be completed. Gating is currently evaluated in clinical settings and is dramatically altered in a variety of psychiatric illnesses. Basic neuroscience research using animals has revealed specific neural sites involved in IG including the hippocampus, thalamus, brainstem, amygdala and medial prefrontal cortex. The present study investigated local IG in the basal ganglia structure of the striatum using chronic recording microwires. We obtained both single unit activations and local field potentials (LFPs) in awake behaving rats from each wire during the standard two-tone paradigm. Single units responded with different types of activations including a phasic and sustained excitation, an inhibitory response and a combination response that contained both excitatory and inhibitory components. IG was observed in all the response types; however, non-gating was observed in a large proportion of responses as well. Positive wave field potentials at 50-60 ms post-stimulus (P60) showed consistent gating across the wire arrays. No significant correlations were found between single unit and LFP measures of gating during the initial baseline session. Gating was strengthened (Tamp/Camp ratios approaching 0) following acute stress (saline injection) at both the single unit and LFP level due to the reduction in the response to the second tone. Alterations in sensory responding reflected by changes in the neural response to the initial tone were primarily observed following long-term internal state deviation (food deprivation) and during general locomotion. Overall, our results support local IG by single neurons in striatum but also suggest that rapid inhibition is not the dominant activation profile observed in other brain regions.
- Published
- 2007
- Full Text
- View/download PDF
9. Auditory inhibitory gating in medial prefrontal cortex: Single unit and local field potential analysis.
- Author
-
Mears RP, Klein AC, and Cromwell HC
- Subjects
- Acoustic Stimulation methods, Animals, Brain Mapping, Rats, Reaction Time physiology, Reflex, Startle physiology, Time Factors, Action Potentials physiology, Evoked Potentials, Auditory physiology, Neural Inhibition physiology, Neurons physiology, Prefrontal Cortex cytology, Prefrontal Cortex physiology
- Abstract
Medial prefrontal cortex is a crucial region involved in inhibitory processes. Damage to the medial prefrontal cortex can lead to loss of normal inhibitory control over motor, sensory, emotional and cognitive functions. The goal of the present study was to examine the basic properties of inhibitory gating in this brain region in rats. Inhibitory gating has recently been proposed as a neurophysiological assay for sensory filters in higher brain regions that potentially enable or disable information throughput. This perspective has important clinical relevance due to the findings that gating is dramatically impaired in individuals with emotional and cognitive impairments (i.e. schizophrenia). We used the standard inhibitory gating two-tone paradigm with a 500 ms interval between tones and a 10 s interval between tone pairs. We recorded both single unit and local field potentials from chronic microwire arrays implanted in the medial prefrontal cortex. We investigated short-term (within session) and long-term (between session) variability of auditory gating and additionally examined how altering the interval between the tones influenced the potency of the inhibition. The local field potentials displayed greater variability with a reduction in the amplitudes of the tone responses over both the short and long-term time windows. The decrease across sessions was most intense for the second tone response (test tone) leading to a more robust gating (lower T/C ratio). Surprisingly, single unit responses of different varieties retained similar levels of auditory responsiveness and inhibition in both the short and long-term analysis. Neural inhibition decreased monotonically related to the increase in intertone interval. This change in gating was most consistent in the local field potentials. Subsets of single unit responses did not show the lack of inhibition even for the longer intertone intervals tested (4 s interval). These findings support the idea that the medial prefrontal cortex is an important site where early inhibitory functions reside and potentially mediate psychological processes.
- Published
- 2006
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.