1
|
Hansen T, Conway BR. The color of fruits in photographs and still life paintings. J Vis 2024; 24:1. [PMID: 38691088 PMCID: PMC11077907 DOI: 10.1167/jov.24.5.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 03/14/2024] [Indexed: 05/03/2024] Open
Abstract
Still life paintings comprise a wealth of data on visual perception. Prior work has shown that the color statistics of objects show a marked bias for warm colors. Here, we ask about the relative chromatic contrast of these object-associated colors compared with background colors in still life paintings. We reasoned that, owing to the memory color effect, where the color of familiar objects is perceived more saturated, warm colors will be relatively more saturated than cool colors in still life paintings as compared with photographs. We analyzed color in 108 slides of still life paintings of fruit from the teaching slide collection of the Fogg University Art Museum and 41 color-calibrated photographs of fruit from the McGill data set. The results show that the relatively higher chromatic contrast of warm colors was greater for paintings compared with photographs, consistent with the hypothesis.
Collapse
Affiliation(s)
- Thorsten Hansen
- Department of Psychology, Justus Liebig University Giessen, Giessen, Germany
| | - Bevil R Conway
- Laboratory of Sensorimotor Research, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
2
|
Hunter D, DeFelipe J, Mehta AR, Conway BR. Art, Intuition, and Identity in Ramón y Cajal. Neuroscientist 2024:10738584241234049. [PMID: 38462512 DOI: 10.1177/10738584241234049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
In the history of neuroscience, Cajal stands tall. Many figures in the late 19th and early 20th centuries made major contributions to neuroscience-Sherrington, Ferrier, Jackson, Holmes, Adrian, and Békésy, to name a few. But in the public mind, Cajal is unique. His application of the Golgi method, with an array of histologic stains, unlocked a wealth of new knowledge on the structure and function of the brain. Here we argue that Cajal's success should not only be attributed to the importance of his scientific contributions but also to the artistic visual language that he created and to his pioneering self-branding, which exploited methods of the artist, including classical drawing and the new invention of photography. We argue that Cajal created his distinctive visual language and self-branding strategy by interweaving an ostensibly objective research product with an intimately subjective narrative about the brain and himself. His approach is evident in the use of photography, notably self-portraits, which furthered broad engagement initially inspired by his scientific drawings. Through his visual language, Cajal made an impact in art and culture far beyond the bounds of science, which has sustained his scientific legacy.
Collapse
Affiliation(s)
- Dawn Hunter
- School of Visual Art and Design, University of South Carolina, Columbia, SC, USA
| | - Javier DeFelipe
- Instituto Cajal-CSIC, Madrid, Spain
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica (UMP), Madrid, Spain
| | - Arpan R Mehta
- National Hospital for Neurology and Neurosurgery, London, UK
- Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
- MRC Protein Phosphorylation & Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute and National Institutes of Mental Health, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
3
|
Malik-Moraleda S, Mahowald K, Conway BR, Gibson E. Concepts Are Restructured During Language Contact: The Birth of Blue and Other Color Concepts in Tsimane'-Spanish Bilinguals. Psychol Sci 2023; 34:1350-1362. [PMID: 37906163 DOI: 10.1177/09567976231199742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023] Open
Abstract
Words and the concepts they represent vary across languages. Here we ask if mother-tongue concepts are altered by learning a second language. What happens when speakers of Tsimane', a language with few consensus color terms, learn Bolivian Spanish, a language with more terms? Three possibilities arise: Concepts in Tsimane' may remain unaffected, or they may be remapped, either by Tsimane' terms taking on new meanings or by borrowing Bolivian-Spanish terms. We found that adult bilingual speakers (n = 30) remapped Tsimane' concepts without importing Bolivian-Spanish terms into Tsimane'. All Tsimane' terms become more precise; for example, concepts of monolingual shandyes and yụshñus (~green or blue, used synonymously by Tsimane' monolinguals; n = 71) come to reflect the Bolivian-Spanish distinction of verde (~green) and azul (~blue). These results show that learning a second language can change the concepts in the first language.
Collapse
Affiliation(s)
- Saima Malik-Moraleda
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology
- McGovern Institute for Brain Research, Massachusetts Institute of Technology
- Program in Speech and Hearing Bioscience and Technology, Harvard University
| | - Kyle Mahowald
- Department of Linguistics, The University of Texas at Austin
| | - Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute and National Institute of Mental Health, Bethesda, MD
| | - Edward Gibson
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology
| |
Collapse
|
4
|
Conway BR, Malik-Moraleda S, Gibson E. Color appearance and the end of Hering's Opponent-Colors Theory. Trends Cogn Sci 2023; 27:791-804. [PMID: 37394292 PMCID: PMC10527909 DOI: 10.1016/j.tics.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 06/02/2023] [Accepted: 06/08/2023] [Indexed: 07/04/2023]
Abstract
Hering's Opponent-Colors Theory has been central to understanding color appearance for 150 years. It aims to explain the phenomenology of colors with two linked propositions. First, a psychological hypothesis stipulates that any color is described necessarily and sufficiently by the extent to which it appears reddish-versus-greenish, bluish-versus-yellowish, and blackish-versus-whitish. Second, a physiological hypothesis stipulates that these perceptual mechanisms are encoded by three innate brain mechanisms. We review the evidence and conclude that neither side of the linking proposition is accurate: the theory is wrong. We sketch out an alternative, Utility-Based Coding, by which the known retinal cone-opponent mechanisms represent optimal encoding of spectral information given competing selective pressure to extract high-acuity spatial information; and phenomenological color categories represent an adaptive, efficient, output of the brain governed by behavioral demands.
Collapse
Affiliation(s)
- Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute and National Institute of Mental Health, Bethesda, MD 20892, USA.
| | - Saima Malik-Moraleda
- Department of Brain and Cognitive Sciences, M.I.T., Cambridge, MA 02139, USA; Program in Speech and Hearing Bioscience and Technology, Harvard University, Cambridge, MA 02114, USA
| | - Edward Gibson
- Department of Brain and Cognitive Sciences, M.I.T., Cambridge, MA 02139, USA
| |
Collapse
|
5
|
Awasthi SM, Garside DJ, Averbeck BB, Conway BR. Color and shape learning in macaque monkeys. J Vis 2022. [DOI: 10.1167/jov.22.14.3316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
| | | | - Bruno B. Averbeck
- National Institute of Mental Health (NIMH), National Institutes of Health
| | | |
Collapse
|
6
|
Chang ALY, Selwyn HM, Garside D, Fuller-Deets J, Awasthi SM, Conway BR. Color categorization in macaques. J Vis 2022. [DOI: 10.1167/jov.22.14.3979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
|
7
|
Bartsch F, Conway BR, Butts DA. Determining how color and form are integrated within macaque V1 neurons through combined neurophysiology and computational modeling. J Vis 2022. [DOI: 10.1167/jov.22.14.3991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Felix Bartsch
- Department of Biology, University of Maryland, College Park, MD, United States of America
- Program in Neuroscience and Cognitive Science, University of Maryland, College Park, MD, United States of America
- Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Bevil R. Conway
- Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Daniel A. Butts
- Department of Biology, University of Maryland, College Park, MD, United States of America
- Program in Neuroscience and Cognitive Science, University of Maryland, College Park, MD, United States of America
| |
Collapse
|
8
|
Rosenthal IA, Singh SR, Hermann KL, Pantazis D, Conway BR. Color Space Geometry Uncovered with Magnetoencephalography. Curr Biol 2022; 32:1670-1674. [PMID: 35413249 DOI: 10.1016/j.cub.2022.03.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
9
|
Khan S, Hasan SS, Bond SE, Conway BR, Aldeyab MA. Antimicrobial consumption in hospitalised COVID-19 patients: a systematic review and meta-analysis. International Journal of Pharmacy Practice 2022. [PMCID: PMC9383618 DOI: 10.1093/ijpp/riac021.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Introduction Despite COVID-19 being a viral illness, antibiotic use has been more prevalent. In addition, co-infection (3.5%) and secondary infection (14.3%) were relatively low in hospitalised patients with COVID-19. A major concern is the increased risk of antimicrobial resistance (AMR) due to inappropriate antibiotic consumption (1). Aim This review aims to evaluate antimicrobial consumption (excluding repurposed drugs such as remdesivir) in hospitals and determine the prevalence of COVID-19 patients who received antibiotic therapy using meta-analysis. Methods The review was conducted according to PRISMA guidelines (2). The two investigators independently developed and applied eligibility criteria to examine original articles. Studies were eligible for inclusion if they met the following criteria: (i) original research studies with a minimum sample of 50 patients; (ii) focussed on antibiotic consumption (AMC); (iii) patients with COVID-19 or consumption amid COVID-19 pandemic; (iv) any age group or gender; and (v) reported in the English language. The included articles were retrieved from MEDLINE, CINAHL, WHO COVID-19 databases, including studies published in EMBASE, Scopus, WHO-COVID, and LILACS between December 2019 to July 2021. The modified version of Newcastle-Ottawa Scale (NOS) was used to measure biases in included studies after the consensus by both authors. The random-effects model was used to estimate the pooled prevalence or proportion of AMC among hospitalized COVID-19 patients. Results A total of 34 studies conducted among hospitalised COVID-19 patients were included. The extracted studies presented AMC in defined daily doses (DDD) or frequency and percentages. Azithromycin was the most frequently prescribed antibiotic in almost all studies. The meta-analysis that examined overall AMC using data from 25 studies (17 studies from high income countries and eight from low-middle income countires) revealed 69% (95% CI:63%-74%) of hospitalized COVID-19 received at least one course of antibiotics. The sub-group analysis of studies from high income countries (HICs) revealed 59% (95% CI: 51%-66%) consumed antibiotics compared with 89% (95% CI: 82% to 94%) among hospitalised COVID-19 patients in low-middle income countries (LMICs). Conclusion This review highlights the trend of antibiotic consumption in hospitalised COVID-19 patients. A significant rise in antibiotic consumption was observed in LMICs and increased antibiotic consumption in the first few months of the COVID-19 pandemic in HIC. The review outcomes emphasised the importance of rational and judicious use of antimicrobial therapy as well as to strenghting the antimicrobial stewardship policies and activities, particularly during a global pandemic. The limitation of the review undertaken was not identified incidence of co-infection and don’t include studies on reported AMC in immunocompromised patients. References (1) Rawson TM, Ming D, Ahmad R, Moore LSP, Holmes AH. Antimicrobial use, drug-resistant infections and COVID-19. Nature reviews Microbiology. 2020;18(8):409-10. (2) Beller EM, Glasziou PP, Altman DG, Hopewell S, Bastian H, Chalmers I, et al. PRISMA for Abstracts: Reporting Systematic Reviews in Journal and Conference Abstracts. PLOS Medicine. 2013;10(4):e1001419.
Collapse
Affiliation(s)
- S Khan
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield, United Kingdom
| | - S S Hasan
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield, United Kingdom
| | - S E Bond
- Pharmacy Department, Mid Yorkshire Hospitals NHS Trust, Wakefield, United Kingdom
| | - B R Conway
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield, United Kingdom
- Institute of Skin Integrity and Infection Prevention, University of Huddersfield, Huddersfield, United Kingdom
| | - M A Aldeyab
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield, United Kingdom
| |
Collapse
|
10
|
Hermann KL, Singh SR, Rosenthal IA, Pantazis D, Conway BR. Temporal dynamics of the neural representation of hue and luminance polarity. Nat Commun 2022; 13:661. [PMID: 35115511 PMCID: PMC8814185 DOI: 10.1038/s41467-022-28249-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 01/12/2022] [Indexed: 11/09/2022] Open
Abstract
Hue and luminance contrast are basic visual features. Here we use multivariate analyses of magnetoencephalography data to investigate the timing of the neural computations that extract them, and whether they depend on common neural circuits. We show that hue and luminance-contrast polarity can be decoded from MEG data and, with lower accuracy, both features can be decoded across changes in the other feature. These results are consistent with the existence of both common and separable neural mechanisms. The decoding time course is earlier and more temporally precise for luminance polarity than hue, a result that does not depend on task, suggesting that luminance contrast is an updating signal that separates visual events. Meanwhile, cross-temporal generalization is slightly greater for representations of hue compared to luminance polarity, providing a neural correlate of the preeminence of hue in perceptual grouping and memory. Finally, decoding of luminance polarity varies depending on the hues used to obtain training and testing data. The pattern of results is consistent with observations that luminance contrast is mediated by both L-M and S cone sub-cortical mechanisms.
Collapse
Affiliation(s)
- Katherine L Hermann
- Laboratory of Sensorimotor Research, National Eye Institute, Bethesda, MD, 20892, USA
- Department of Psychology, Stanford University, Stanford, CA, 94305, USA
| | - Shridhar R Singh
- Laboratory of Sensorimotor Research, National Eye Institute, Bethesda, MD, 20892, USA
| | - Isabelle A Rosenthal
- Laboratory of Sensorimotor Research, National Eye Institute, Bethesda, MD, 20892, USA
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Dimitrios Pantazis
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute, Bethesda, MD, 20892, USA.
- National Institute of Mental Health, Bethesda, MD, 20892, USA.
| |
Collapse
|
11
|
Vaziri-Pashkam M, Conway BR. How The visual system turns things the right way up. Cogn Neuropsychol 2022; 39:54-57. [PMID: 35624546 PMCID: PMC10759311 DOI: 10.1080/02643294.2022.2073808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/09/2022] [Accepted: 04/20/2022] [Indexed: 11/03/2022]
Affiliation(s)
- Maryam Vaziri-Pashkam
- Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, MD, USA
| | - Bevil R. Conway
- Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, MD, USA
- Laboratory of Sensorimotor Research, National Eye Institute, Bethesda, MD, USA
| |
Collapse
|
12
|
Abstract
Bevil Conway introduces colors.
Collapse
Affiliation(s)
- Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute and National Institute of Mental Health, Bethesda, MD 20892, USA.
| |
Collapse
|
13
|
Rosenthal IA, Singh SR, Hermann KL, Pantazis D, Conway BR. Color Space Geometry Uncovered with Magnetoencephalography. Curr Biol 2021; 31:1127-1128. [PMID: 33689711 DOI: 10.1016/j.cub.2021.02.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
14
|
Rosenthal IA, Singh SR, Hermann KL, Pantazis D, Conway BR. Color Space Geometry Uncovered with Magnetoencephalography. Curr Biol 2021; 31:515-526.e5. [PMID: 33202253 PMCID: PMC7878424 DOI: 10.1016/j.cub.2020.10.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/21/2020] [Accepted: 10/21/2020] [Indexed: 02/07/2023]
Abstract
The geometry that describes the relationship among colors, and the neural mechanisms that support color vision, are unsettled. Here, we use multivariate analyses of measurements of brain activity obtained with magnetoencephalography to reverse-engineer a geometry of the neural representation of color space. The analyses depend upon determining similarity relationships among the spatial patterns of neural responses to different colors and assessing how these relationships change in time. We evaluate the approach by relating the results to universal patterns in color naming. Two prominent patterns of color naming could be accounted for by the decoding results: the greater precision in naming warm colors compared to cool colors evident by an interaction of hue and lightness, and the preeminence among colors of reddish hues. Additional experiments showed that classifiers trained on responses to color words could decode color from data obtained using colored stimuli, but only at relatively long delays after stimulus onset. These results provide evidence that perceptual representations can give rise to semantic representations, but not the reverse. Taken together, the results uncover a dynamic geometry that provides neural correlates for color appearance and generates new hypotheses about the structure of color space.
Collapse
Affiliation(s)
- Isabelle A Rosenthal
- Laboratory of Sensorimotor Research, National Eye Institute, Building 49, NIH Main Campus, Bethesda, MD 20892, USA
| | - Shridhar R Singh
- Laboratory of Sensorimotor Research, National Eye Institute, Building 49, NIH Main Campus, Bethesda, MD 20892, USA
| | - Katherine L Hermann
- Laboratory of Sensorimotor Research, National Eye Institute, Building 49, NIH Main Campus, Bethesda, MD 20892, USA
| | - Dimitrios Pantazis
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, 524 Main Street, Cambridge, MA 02139, USA
| | - Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute, Building 49, NIH Main Campus, Bethesda, MD 20892, USA; National Institute of Mental Health, Bethesda, MD 20892, USA.
| |
Collapse
|
15
|
Abstract
Color is a fundamental aspect of normal visual experience. This chapter provides an overview of the role of color in human behavior, a survey of current knowledge regarding the genetic, retinal, and neural mechanisms that enable color vision, and a review of inherited and acquired defects of color vision including a discussion of diagnostic tests.
Collapse
Affiliation(s)
- Joseph Carroll
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, United States.
| | - Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, Bethesda, MD, United States.
| |
Collapse
|
16
|
Totea AM, Dorin I, Laity PR, Sabin J, Conway BR, Waters L, Asare-Addo K. A molecular understanding of magnesium aluminium silicate - drug, drug - polymer, magnesium aluminium silicate - polymer nanocomposite complex interactions in modulating drug release: Towards zero order release. Eur J Pharm Biopharm 2020; 154:270-282. [PMID: 32717386 DOI: 10.1016/j.ejpb.2020.07.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/06/2020] [Accepted: 07/22/2020] [Indexed: 10/23/2022]
Abstract
This study reports the use of ITC in understanding the thermodynamics occurring for a controlled release system in which complexation has been exploited. In this study, a model drug, propranolol hydrochloride (PPN) was complexed with magnesium aluminium silicate (MAS) and these complexes were used in combination with polyethylene oxide (PEO) as a hydrophilic carrier at various concentrations to sustain the release of PPN. DSC, XRPD, ATR-FTIR and SEM/EDX were successfully used in characterising the produced complexes. 2D- SAXS data patterns for MAS and the produced complexes were shown to be symmetric and circular with the particles showing no preferred orientation at the nanometre scale. ITC studies showed differences between PPN adsorption onto MAS compared with PPN adsorption onto a MAS-PEO mixture. At both temperatures studied the binding affinity Ka was greater for the titration of PPN into the MAS-PEO mixture (5.37E + 04 ± 7.54E + 03 M at 25 °C and 8.63E + 04 ± 6.11E + 03 M at 37 °C), compared to the affinity obtained upon binding between PPN and MAS as previously reported suggesting a stronger binding with implications for the dissolution process. MAS-PPN complexes with the PEO polymer compacts displayed desired manufacturing and formulation properties for a formulator including, reduced plastic recovery therefore potentially reducing the risk of cracking/splitting and on tooling wear, controlled release of PPN at a significantly low (5%) polymer level as well as a zero-order release profile (case II transport) using up to 50% polymer level.
Collapse
Affiliation(s)
- A M Totea
- School of Applied Sciences, Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - I Dorin
- Biomolecular Formulation and Characterization Sciences, UCB, Slough SL3WE, UK
| | - P R Laity
- Department of Materials Science and Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, UK
| | - Juan Sabin
- AFFINImeter, Edificio Emprendia, Campus Vida, Santiago de Compostela, Spain
| | - B R Conway
- School of Applied Sciences, Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - L Waters
- School of Applied Sciences, Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - K Asare-Addo
- School of Applied Sciences, Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK.
| |
Collapse
|
17
|
Senjoti FG, Timmins P, Conway BR, Smith AM. Optimizing ophthalmic delivery of a poorly water soluble drug from an aqueous in situ gelling system. Eur J Pharm Biopharm 2020; 154:1-7. [PMID: 32599271 DOI: 10.1016/j.ejpb.2020.06.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/26/2020] [Accepted: 06/22/2020] [Indexed: 12/24/2022]
Abstract
Poorly soluble drugs are often unsuitable to incorporate in ocular in situ gelling systems due to the aqueous based gelling formulations and low volumes administered. For such formulations to be successful, the administered drug must have sufficient solubility to diffuse from the formulation to the eye and should not affect the gelation of the in situ gelling material. Drug salt forms can improve the solubility of poorly soluble drugs, however, as in situ gel forming formulations are often designed to be crosslinked by salts (present the lacrimal fluid) it can make salt forms difficult to formulate. The aim of this study was to develop an in situ gel forming ophthalmic formulation of a poorly soluble drug flurbiprofen (FBP) through cyclodextrin complex formation and to analyse the impact on gelation, release and permeation through the cornea. Hydroxypropyl-beta-cyclodextrin (HβCD) was used as a complexing agent and low acyl gellan gum was added to the FBP- HβCD complex as a water soluble in situ gelling polymer. Measurements were performed using rheo-dissolution, which utilises a rheometer with a modified lower plate that has the unique ability to allow rheological measurement and analysis of drug release simultaneously. An ex-vivo permeation study was also performed using porcine cornea. Rheological measurements in terms of elastic (G') and viscous (G″) modulus showed rapid gelation of the formulation upon contact with simulated lacrimal fluid (SLF). Approximately, 97% FBP was released when 10% HβCD was used and release was decreased to 79% when the amount of HβCD was increased to 20%. The percentage of drug permeation through the cornea was 55% in 300 min whereas the marketed non gelling eye drop formulation containing FBP sodium showed only 37% permeation. The data presented here, revealed that not only could a poorly soluble drug be complexed with cyclodextrin and loaded into an in situ gelling system without interfering with the gelation, but also permeability the of the drug improved.
Collapse
Affiliation(s)
- F G Senjoti
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - P Timmins
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - B R Conway
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - A M Smith
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK.
| |
Collapse
|
18
|
Nirwan JS, Farhaj S, Chaudhary MM, Khizer Z, Hasan SS, Angelis-Dimakis A, Gill A, Rasheed H, Abbas N, Arshad MS, Hussain T, Shahzad Y, Yousaf AM, Chohan TA, Hussain T, Merchant HA, Akram MR, Khan TM, Ashraf M, Conway BR, Ghori MU. Exploration of a New Source of Sustainable Nanomaterial from the Koh-e-Suleiman Mountain Range of Pakistan for Industrial Applications. Sci Rep 2020; 10:577. [PMID: 31953500 PMCID: PMC6969096 DOI: 10.1038/s41598-020-57511-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 12/27/2019] [Indexed: 11/29/2022] Open
Abstract
The present study aimed to explore a new source of montmorillonite and to develop an extraction and purification protocol for its isolation from raw clay samples acquired from the Koh-e-Suleiman mountain range in Pakistan. The process involved the collection of raw clay from the source, identification and quantification of montmorillonite. Granulometric extraction and purification protocols increased the montmorillonite content from 21.8-25.1% in the raw clay to 90.1-93.9% after small-scale extraction and 85.33-89.33% on a larger scale. A techno-economic analysis highlighted the practicality and economic benefits of large-scale extraction for industrial applications. This study highlights the existence of a substantial new source of this valuable clay which is currently used across multiple industries including construction, pottery making, pharmaceuticals, cosmetics and engineering. It is intuitively expected that the large-scale extraction of the material will improve the economic condition of the region by providing employment opportunities to locals and may be a valuable resource for export.
Collapse
Affiliation(s)
- J S Nirwan
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | - S Farhaj
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | | | - Z Khizer
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | - S S Hasan
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | - A Angelis-Dimakis
- Department of Chemical Sciences, University of Huddersfield, Huddersfield, UK
| | - A Gill
- Ministry of Minerals and Mines, Lahore, Punjab, Pakistan
| | - H Rasheed
- Pakistan Council of research for Water Resources (PCRWR), Ministry of Science and Technology, Islamabad, Pakistan
| | - N Abbas
- University College of Pharmacy, the University of Punjab, Lahore, Pakistan
| | - M S Arshad
- Faculty of Pharmacy, Bahuddin Zakariya University Multan, Multan, Pakistan
| | - T Hussain
- Department of Pharmacy, COMSAT University Islamabad, Lahore Campus, Lahore, Pakistan
| | - Y Shahzad
- Department of Pharmacy, COMSAT University Islamabad, Lahore Campus, Lahore, Pakistan
| | - A M Yousaf
- Department of Pharmacy, COMSAT University Islamabad, Lahore Campus, Lahore, Pakistan
| | - T A Chohan
- Institute of Pharmaceutical Sciences, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - T Hussain
- The Wolfson Centre for Bulk Solid Handling Technology, University of Greenwich, London, UK
- System Engineering Department, Military Technological College, Muscat, Oman
| | - H A Merchant
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | - M R Akram
- College of Pharmacy, University of Sargodha, Sargodha, 40100, Pakistan
| | - T M Khan
- Institute of Pharmaceutical Sciences, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - M Ashraf
- Pakistan Council of research for Water Resources (PCRWR), Ministry of Science and Technology, Islamabad, Pakistan
| | - B R Conway
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | - M U Ghori
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK.
| |
Collapse
|
19
|
Nep EI, Kaur N, Shaboun S, Adebisi AO, Smith AM, Conway BR, Asare-Addo K. Mechanical and release behaviour of theophylline from matrix tablets containing psyllium powder in combination with grewia polysaccharides. Colloids Surf B Biointerfaces 2020; 188:110809. [PMID: 31972440 DOI: 10.1016/j.colsurfb.2020.110809] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 01/08/2020] [Accepted: 01/16/2020] [Indexed: 10/25/2022]
Abstract
This study was aimed at investigating the effect of grewia polysaccharides on the mechanical and release properties of tablet matrices containing binary mixtures of the polysaccharide with psyllium. Two grades of grewia polysaccharides (GG and GDS) were extracted and binary mixtures of the polysaccharides with psyllium were formulated into tablet matrices containing theophylline as the model drug. The true, bulk and tapped densities, Carr's compressibility index of the powders and binary composites were determined before tablet compression. Tablet properties (hardness, porosity, and drug release from the matrices) were investigated. The dissolution test was carried out in 0.1 M HCl (pH 1.2) and phosphate buffer (pH 6.8). The results show that GG and GDS produced tablets with good mechanical strength (108.33 N and 95.70 N, respectively) while psyllium produced softer tablets (7.13 N). The combination of psyllium and grewia polysaccharides in the matrices resulted in a significant increase in the mechanical strength of the matrices when compared to matrices containing psyllium alone as the matrix former. The results also showed that GG and GDS reduced the dissolution rate and effectively eliminated the burst release of theophylline from the psyllium matrices at both pHs. The matrices of GG or GDS and the binary mixtures conform to non-Fickian anomalous diffusion with n > 0.45. When overcoming the burst release of drug from matrices such as psyllium, grewia polysaccharides may provide an effective reduction and a more sustained drug release from such matrices.
Collapse
Affiliation(s)
- E I Nep
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, HD1, 3DH, UK; Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmaceutical Science, University of Jos, PMB 2084, Jos, 930001, Nigeria
| | - N Kaur
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, HD1, 3DH, UK
| | - S Shaboun
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, HD1, 3DH, UK; Pharmaceutical Chemistry Department, Faculty of Pharmacy, University of Benghazi, Libya
| | - A O Adebisi
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, HD1, 3DH, UK
| | - A M Smith
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, HD1, 3DH, UK
| | - B R Conway
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, HD1, 3DH, UK
| | - K Asare-Addo
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, HD1, 3DH, UK.
| |
Collapse
|
20
|
Affiliation(s)
- Isabelle Rosenthal
- National Eye Institute
- present address: California Institute of Technology
| | | | | | | | | |
Collapse
|
21
|
Abstract
What is color vision for? Here we compared the extent to which memory modulates color appearance of objects and faces. Participants matched the colors of stimuli illuminated by low-pressure sodium light, which renders scenes monochromatic. Matches for fruit were not predicted by stimulus identity. In contrast, matches for faces were predictable, but surprising: faces appeared green and looked sick. The paradoxical face-color percept could be explained by a Bayesian observer model constrained by efficient coding. The color-matching data suggest that the face-color prior is established by visual signals arising from the recently evolved L-M cone system, not the older S-cone channel. Taken together, the results show that when retinal mechanisms of color vision are impaired, the impact of memory on color perception is greatest for face color, supporting the idea that trichromatic color plays an important role in social communication. What is the function of color vision? Here, the authors show that when retinal mechanisms of color are impaired, memory has a paradoxical impact on color appearance that is selective for faces, providing evidence that color contributes to face encoding and social communication.
Collapse
Affiliation(s)
- Maryam Hasantash
- Institute for Research in Fundamental Sciences, Tehran, P.O. Box 19395-5746, Iran
| | - Rosa Lafer-Sousa
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, 02139, USA
| | - Arash Afraz
- National Institute of Mental Health, NIH, Bethesda, MD, 20892, USA
| | - Bevil R Conway
- National Institute of Mental Health, NIH, Bethesda, MD, 20892, USA. .,National Eye Institute, NIH, Bethesda, MD, 20892, USA.
| |
Collapse
|
22
|
Kramer A, Conway BR, Meissner K, Scholz F, Rauch BH, Moroder A, Ehlers A, Meixner AJ, Heidecke CD, Partecke LI, Kietzmann M, Assadian O. Cold atmospheric pressure plasma for treatment of chronic wounds: drug or medical device? J Wound Care 2019; 26:470-475. [PMID: 28795892 DOI: 10.12968/jowc.2017.26.8.470] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE The use of cold atmospheric pressure plasma (CAPP) as a new therapeutic option to aid the healing of chronic wounds appears promising. Currently, uncertainty exists regarding their classification as medical device or medical drug. Because the classification of CAPP has medical, legal, and economic consequences as well as implications for the level of preclinical and clinical testing, the correct classification is not an academic exercise, but an ethical need. METHOD A multidisciplinary team of physicians, surgeons, pharmacists, physicists and lawyers has analysed the physical and technical characteristics as well as legal conditions of the biological action of CAPP. RESULTS It was concluded that the mode of action of the locally generated CAPP, with its main active components being different radicals, is pharmacological and not physical in nature. CONCLUSION Depending on the intended use, CAPP should be classified as a drug, which is generated by use of a medical device directly at the point of therapeutic application.
Collapse
Affiliation(s)
- A Kramer
- Consultant Clinical Microbiology and Infection Control, Institute of Hygiene and Environmental Medicine, University Medicine Greifswald, Germany
| | - B R Conway
- Department of Pharmacy, School of Applied Sciences, University of Huddersfield, United Kingdom; Institute of Skin Integrity and Infection Prevention, School for Human and Health Sciences, University of Huddersfield
| | - K Meissner
- Anesthetist, Intensive Care Specialist, Department of Anesthesiology and Intensive Medicine, University Medicine, Greifswald, Germany
| | - F Scholz
- Biochemist, Institute of Biochemistry, University of Greifswald, Germany
| | - B H Rauch
- Medical Pharmacology and Toxicology, Department of Pharmacology, Center of Drug Absorption and Transport, University Medicine Greifswald, Germany
| | - A Moroder
- Lawyer, Ehlers, Ehlers & Partner Healthcare Law Firm Munich, Germany
| | - A Ehlers
- Lawyer, Ehlers, Ehlers & Partner Healthcare Law Firm Munich, Germany
| | - A J Meixner
- Physicist, Institute of Physical and Theoretical Chemistry Tübingen, Germany
| | - C-D Heidecke
- General Surgeon, Department of Surgery, University Medicine Greifswald, Germany
| | - L I Partecke
- General Surgeon, Department of Surgery, University Medicine Greifswald, Germany
| | - M Kietzmann
- Veterinary Medicine, Pharmacologist, Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - O Assadian
- Consultant Clinical Microbiology and Infection Control, Consultant Infectious Diseases and Tropical Medicine, Institute for Hospital Epidemiology and Infection Control, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
23
|
Norman-Haignere SV, Kanwisher N, McDermott JH, Conway BR. Divergence in the functional organization of human and macaque auditory cortex revealed by fMRI responses to harmonic tones. Nat Neurosci 2019; 22:1057-1060. [PMID: 31182868 PMCID: PMC6592717 DOI: 10.1038/s41593-019-0410-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 04/19/2019] [Indexed: 12/02/2022]
Abstract
We report a difference between humans and macaque monkeys in the functional organization of cortical regions implicated in pitch perception: humans but not macaques showed regions with a strong preference for harmonic sounds compared to noise, measured with both synthetic tones and macaque vocalizations. In contrast, frequency-selective tonotopic maps were similar between the two species. This species difference may be driven by the unique demands of speech and music perception in humans.
Collapse
Affiliation(s)
- Sam V Norman-Haignere
- Zuckerman Institute for Mind, Brain and Behavior, Columbia University, New York, NY, USA. .,Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA. .,HHMI Postdoctoral Fellow of the Life Sciences Research Institute, Chevy Chase, MD, USA. .,Laboratoire des Systèmes Perceptifs, Département d'Études Cognitives, École Normale Supérieure, PSL University, CNRS, Paris, France.
| | - Nancy Kanwisher
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA.,McGovern Institute for Brain Research, Cambridge, MA, USA.,Center for Minds, Brains and Machines, Cambridge, MA, USA
| | - Josh H McDermott
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA.,McGovern Institute for Brain Research, Cambridge, MA, USA.,Center for Minds, Brains and Machines, Cambridge, MA, USA.,Program in Speech and Hearing Biosciences and Technology, Harvard University, Cambridge, MA, USA
| | - Bevil R Conway
- Laboratory of Sensorimotor Research, NEI, NIH, Bethesda, MD, USA. .,National Institute of Mental Health, NIH, Bethesda, MD, USA. .,National Institute of Neurological Disease and Stroke, NIH, Bethesda, MD, USA.
| |
Collapse
|
24
|
Rosenthal I, Ratnasingam S, Haile T, Eastman S, Fuller-Deets J, Conway BR. Color statistics of objects, and color tuning of object cortex in macaque monkey. J Vis 2019; 18:1. [PMID: 30285103 PMCID: PMC6168048 DOI: 10.1167/18.11.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
We hypothesized that the parts of scenes identified by human observers as “objects” show distinct color properties from backgrounds, and that the brain uses this information towards object recognition. To test this hypothesis, we examined the color statistics of naturally and artificially colored objects and backgrounds in a database of over 20,000 images annotated with object labels. Objects tended to be warmer colored (L-cone response > M-cone response) and more saturated compared to backgrounds. That the distinguishing chromatic property of objects was defined mostly by the L-M post-receptoral mechanism, rather than the S mechanism, is consistent with the idea that trichromatic color vision evolved in response to a selective pressure to identify objects. We also show that classifiers trained using only color information could distinguish animate versus inanimate objects, and at a performance level that was comparable to classification using shape features. Animate/inanimate is considered a fundamental superordinate category distinction, previously thought to be computed by the brain using only shape information. Our results show that color could contribute to animate/inanimate, and likely other, object-category assignments. Finally, color-tuning measured in two macaque monkeys with functional magnetic resonance imaging (fMRI), and confirmed by fMRI-guided microelectrode recording, supports the idea that responsiveness to color reflects the global functional organization of inferior temporal cortex, the brain region implicated in object vision. More strongly in IT than in V1, colors associated with objects elicited higher responses than colors less often associated with objects.
Collapse
Affiliation(s)
- Isabelle Rosenthal
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Sivalogeswaran Ratnasingam
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Theodros Haile
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Serena Eastman
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Josh Fuller-Deets
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
25
|
Haile TM, Bohon KS, Romero MC, Conway BR. Visual stimulus-driven functional organization of macaque prefrontal cortex. Neuroimage 2019; 188:427-444. [PMID: 30521952 PMCID: PMC6401279 DOI: 10.1016/j.neuroimage.2018.11.060] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/20/2018] [Accepted: 11/30/2018] [Indexed: 12/29/2022] Open
Abstract
The extent to which the major subdivisions of prefrontal cortex (PFC) can be functionally partitioned is unclear. In approaching the question, it is often assumed that the organization is task dependent. Here we use fMRI to show that PFC can respond in a task-independent way, and we leverage these responses to uncover a stimulus-driven functional organization. The results were generated by mapping the relative location of responses to faces, bodies, scenes, disparity, color, and eccentricity in four passively fixating macaques. The results control for individual differences in functional architecture and provide the first account of a systematic visual stimulus-driven functional organization across PFC. Responses were focused in dorsolateral PFC (DLPFC), in the ventral prearcuate region; and in ventrolateral PFC (VLPFC), extending into orbital PFC. Face patches were in the VLPFC focus and were characterized by a striking lack of response to non-face stimuli rather than an especially strong response to faces. Color-biased regions were near but distinct from face patches. One scene-biased region was consistently localized with different contrasts and overlapped the disparity-biased region to define the DLPFC focus. All visually responsive regions showed a peripheral visual-field bias. These results uncover an organizational scheme that presumably constrains the flow of information about different visual modalities into PFC.
Collapse
Affiliation(s)
- Theodros M Haile
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, National Institutes of Health, 20892, Bethesda, United States
| | - Kaitlin S Bohon
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, National Institutes of Health, 20892, Bethesda, United States
| | - Maria C Romero
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, National Institutes of Health, 20892, Bethesda, United States
| | - Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, National Institutes of Health, 20892, Bethesda, United States.
| |
Collapse
|
26
|
Conway BR, Eskew RT, Martin PR, Stockman A. Editorial. Vision Res 2018; 151:1. [PMID: 30327094 DOI: 10.1016/j.visres.2018.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bevil R Conway
- National Eye Institute and National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892
| | - Rhea T Eskew
- Department of Psychology, 125 Nightingale Hall, Northeastern University, Boston MA 02115, USA
| | - Paul R Martin
- Save Sight Institute and School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Andrew Stockman
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, England
| |
Collapse
|
27
|
Abstract
The study of color vision encompasses many disciplines, including art, biochemistry, biophysics, brain imaging, cognitive neuroscience, color preferences, colorimetry, computer modelling, design, electrophysiology, language and cognition, molecular genetics, neuroscience, physiological optics, psychophysics and physiological optics. Coupled with the elusive nature of the subjective experience of color, this wide range of disciplines makes the study of color as challenging as it is fascinating. This overview of the special issue Color: Cone Opponency and Beyond outlines the state of the science of color, and points to some of the many questions that remain to be answered in this exciting field.
Collapse
Affiliation(s)
- Bevil R Conway
- National Eye Institute and National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rhea T Eskew
- Department of Psychology, 125 Nightingale Hall, Northeastern University, Boston, MA 02115, USA
| | - Paul R Martin
- Save Sight Institute and School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Andrew Stockman
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, England, United Kingdom
| |
Collapse
|
28
|
Abstract
Inferior temporal cortex (IT) is a key part of the ventral visual pathway implicated in object, face, and scene perception. But how does IT work? Here, I describe an organizational scheme that marries form and function and provides a framework for future research. The scheme consists of a series of stages arranged along the posterior-anterior axis of IT, defined by anatomical connections and functional responses. Each stage comprises a complement of subregions that have a systematic spatial relationship. The organization of each stage is governed by an eccentricity template, and corresponding eccentricity representations across stages are interconnected. Foveal representations take on a role in high-acuity object vision (including face recognition); intermediate representations compute other aspects of object vision such as behavioral valence (using color and surface cues); and peripheral representations encode information about scenes. This multistage, parallel-processing model invokes an innately determined organization refined by visual experience that is consistent with principles of cortical development. The model is also consistent with principles of evolution, which suggest that visual cortex expanded through replication of retinotopic areas. Finally, the model predicts that the most extensively studied network within IT-the face patches-is not unique but rather one manifestation of a canonical set of operations that reveal general principles of how IT works.
Collapse
Affiliation(s)
- Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland 28092, USA; .,National Institutes of Mental Health, National Institute of Neurological Disease and Stroke, National Institutes of Health, Bethesda, Maryland 28092, USA
| |
Collapse
|
29
|
Abstract
We present a full analysis of data from our preliminary report (Lafer-Sousa, Hermann, & Conway, 2015) and test whether #TheDress image is multistable. A multistable image must give rise to more than one mutually exclusive percept, typically within single individuals. Clustering algorithms of color-matching data showed that the dress was seen categorically, as white/gold (W/G) or blue/black (B/K), with a blue/brown transition state. Multinomial regression predicted categorical labels. Consistent with our prior hypothesis, W/G observers inferred a cool illuminant, whereas B/K observers inferred a warm illuminant; moreover, subjects could use skin color alone to infer the illuminant. The data provide some, albeit weak, support for our hypothesis that day larks see the dress as W/G and night owls see it as B/K. About half of observers who were previously familiar with the image reported switching categories at least once. Switching probability increased with professional art experience. Priming with an image that disambiguated the dress as B/K biased reports toward B/K (priming with W/G had negligible impact); furthermore, knowledge of the dress's true colors and any prior exposure to the image shifted the population toward B/K. These results show that some people have switched their perception of the dress. Finally, consistent with a role of attention and local image statistics in determining how multistable images are seen, we found that observers tended to discount as achromatic the dress component that they did not attend to: B/K reporters focused on a blue region, whereas W/G reporters focused on a golden region.
Collapse
Affiliation(s)
- Rosa Lafer-Sousa
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute, and National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
30
|
Nep EI, Mahdi MH, Adebisi AO, Dawson C, Walton K, Bills PJ, Conway BR, Smith AM, Asare-Addo K. The influence of hydroalcoholic media on the performance of Grewia polysaccharide in sustained release tablets. Int J Pharm 2017; 532:352-364. [PMID: 28903068 DOI: 10.1016/j.ijpharm.2017.09.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/23/2017] [Accepted: 09/09/2017] [Indexed: 11/15/2022]
Abstract
Co-administration of drugs with alcohol can affect the plasma concentration of drugs in patients. It is also known that the excipients used in the formulation of drugs may not always be resistant to alcohol. This study evaluates effect of varying alcohol concentrations on theophylline release from two grades of Grewia mollis polysaccharides. X-ray microtomography showed that native polysaccharide formulation compacts were not homogenous after the mixing process resulting in its failure in swelling studies. Removal of starch from the native polysaccharide resulted in homogenous formulation compacts resistant to damage in high alcoholic media in pH 6.8 (40%v/v absolute ethanol). Destarched polymer compacts had a significantly higher hardness (375N) than that of the native polysaccharide (82N) and HPMC K4M (146N). Dissolution studies showed similarity at all levels of alcohol tested (f2=57-91) in simulated gastric media (pH 1.2). The dissolution profiles in the simulated intestinal fluids were also similar (f2=60-94), with the exception of the native polysaccharide in pH 6.8 (40%v/v absolute ethanol) (f2=43). This work highlights the properties of Grewia polysaccharide as a matrix former that can resist high alcoholic effects therefore; it may be suitable as an alternative to some of the commercially available matrix formers with wider applications for drug delivery as a cheaper alternative in the developing world.
Collapse
Affiliation(s)
- E I Nep
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK; Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmaceutical Science, University of Jos, PMB 2084, Jos 930001, Nigeria.
| | - M H Mahdi
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - A O Adebisi
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - C Dawson
- EPSRC Future Metrology Hub, University of Huddersfield, Huddersfield HD1 3DH, UK
| | - K Walton
- EPSRC Future Metrology Hub, University of Huddersfield, Huddersfield HD1 3DH, UK
| | - P J Bills
- EPSRC Future Metrology Hub, University of Huddersfield, Huddersfield HD1 3DH, UK
| | - B R Conway
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - A M Smith
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - K Asare-Addo
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK.
| |
Collapse
|
31
|
Casey AL, Karpanen TJ, Conway BR, Worthington T, Nightingale P, Waters R, Elliott TSJ. Enhanced chlorhexidine skin penetration with 1,8-cineole. BMC Infect Dis 2017; 17:350. [PMID: 28514947 PMCID: PMC5436417 DOI: 10.1186/s12879-017-2451-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 05/08/2017] [Indexed: 11/29/2022] Open
Abstract
Background Chlorhexidine (CHG) penetrates poorly into skin. The purpose of this study was to compare the depth of CHG skin permeation from solutions containing either 2% (w/v) CHG and 70% (v/v) isopropyl alcohol (IPA) or 2% (w/v) CHG, 70% (v/v) IPA and 2% (v/v) 1,8-cineole. Methods An ex-vivo study using Franz diffusion cells was carried out. Full thickness human skin was mounted onto the cells and a CHG solution, with or without 2% (v/v) 1,8-cineole was applied to the skin surface. After twenty-four hours the skin was sectioned horizontally in 100 μm slices to a depth of 2000 μm and the concentration of CHG in each section quantified using high performance liquid chromatography (HPLC). The data were analysed with repeated measures analysis of variance. Results The concentration of CHG in the skin on average was significantly higher (33.3% [95%, CI 1.5% - 74.9%]) when a CHG solution which contained 1,8-cineole was applied to the skin compared to a CHG solution which did not contain this terpene (P = 0.042). Conclusions Enhanced delivery of CHG can be achieved in the presence of 1,8-cineole, which is the major component of eucalyptus oil. This may reduce the numbers of microorganisms located in the deeper layers of the skin which potentially could decrease the risk of surgical site infection.
Collapse
Affiliation(s)
- A L Casey
- Department of Clinical Microbiology, University Hospitals Birmingham NHS Foundation Trust, Edgbaston, B15 2WB, Birmingham, UK
| | - T J Karpanen
- Department of Clinical Microbiology, University Hospitals Birmingham NHS Foundation Trust, Edgbaston, B15 2WB, Birmingham, UK
| | - B R Conway
- Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK
| | - T Worthington
- School of Life and Health Sciences, Aston University, B4 7ET, Birmingham, UK
| | - P Nightingale
- Wolfson Computer Laboratory, University Hospitals Birmingham NHS Foundation Trust, B15 2TH, Birmingham, UK
| | - R Waters
- Department of Burns and Plastics, University Hospitals Birmingham NHS Foundation Trust, B15 2WB, Birmingham, UK
| | - T S J Elliott
- Department of Clinical Microbiology, University Hospitals Birmingham NHS Foundation Trust, Edgbaston, B15 2WB, Birmingham, UK. .,Clinical Governance, The Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Edgbaston, B15 2TH, Birmingham, UK.
| |
Collapse
|
32
|
Mullins LJ, Kenyon CJ, Bailey MA, Conway BR, Diaz ME, Mullins JJ. Mineralocorticoid excess or glucocorticoid insufficiency: renal and metabolic phenotypes in a rat Hsd11b2 knockout model. Hypertension 2015; 66:e20. [PMID: 26269656 DOI: 10.1161/hyp.0000000000000035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
33
|
Beltz BS, Benton JL, Conway BR, Johnson BR, Quinan V, Tetel MJ, Wiest MC. The 2014 FUN Achievement Award. J Undergrad Neurosci Educ 2015; 13:E11-E13. [PMID: 26240536 PMCID: PMC4521744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Affiliation(s)
| | | | - Bevil R. Conway
- Neuroscience Program, Wellesley College, Wellesley, MA 02481
| | - Bruce R. Johnson
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853
| | - Virginia Quinan
- Neuroscience Program, Wellesley College, Wellesley, MA 02481
| | - Marc J. Tetel
- Neuroscience Program, Wellesley College, Wellesley, MA 02481
| | | |
Collapse
|
34
|
Abstract
'The dress' is a peculiar photograph: by themselves the dress' pixels are brown and blue, colors associated with natural illuminants, but popular accounts (#TheDress) suggest the dress appears either white/gold or blue/black. Could the purported categorical perception arise because the original social-media question was an alternative-forced-choice? In a free-response survey (N = 1401), we found that most people, including those naïve to the image, reported white/gold or blue/black, but some said blue/brown. Reports of white/gold over blue/black were higher among older people and women. On re-test, some subjects reported a switch in perception, showing the image can be multistable. In a language-independent measure of perception, we asked subjects to identify the dress' colors from a complete color gamut. The results showed three peaks corresponding to the main descriptive categories, providing additional evidence that the brain resolves the image into one of three stable percepts. We hypothesize that these reflect different internal priors: some people favor a cool illuminant (blue sky), discount shorter wavelengths, and perceive white/gold; others favor a warm illuminant (incandescent light), discount longer wavelengths, and see blue/black. The remaining subjects may assume a neutral illuminant, and see blue/brown. We show that by introducing overt cues to the illumination, we can flip the dress color.
Collapse
Affiliation(s)
- Rosa Lafer-Sousa
- Department of Brain and Cognitive Sciences, MIT, Cambridge MA 02139
| | - Katherine L. Hermann
- Neuroscience Program, Wellesley College, Wellesley MA, 02481; Department of Brain and Cognitive Sciences, MIT, Cambridge MA 02139
| | - Bevil R. Conway
- Neuroscience Program, Wellesley College, Wellesley MA, 02481; Department of Brain and Cognitive Sciences, MIT, Cambridge MA 02139
| |
Collapse
|
35
|
Zaidi Q, Marshall J, Thoen H, Conway BR. Evolution of neural computations: Mantis shrimp and human color decoding. Iperception 2014; 5:492-6. [PMID: 26034560 PMCID: PMC4441025 DOI: 10.1068/i0662sas] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 08/14/2014] [Indexed: 11/08/2022] Open
Abstract
Mantis shrimp and primates both possess good color vision, but the neural implementation in the two species is very different, a reflection of the largely unrelated evolutionary lineages of these creatures. Mantis shrimp have scanning compound eyes with 12 classes of photoreceptors, and have evolved a system to decode color information at the front-end of the sensory stream. Primates have image-focusing eyes with three classes of cones, and decode color further along the visual-processing hierarchy. Despite these differences, we report a fascinating parallel between the computational strategies at the color-decoding stage in the brains of stomatopods and primates. Both species appear to use narrowly tuned cells that support interval decoding color identification.
Collapse
Affiliation(s)
- Qasim Zaidi
- Graduate Center for Vision Research, State University of New York, New York; e-mail:
| | - Justin Marshall
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia; e-mail:
| | - Hanne Thoen
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia; e-mail:
| | - Bevil R Conway
- Neuroscience Program, Wellesley College, Wellesley, Massachusetts; e-mail:
| |
Collapse
|
36
|
Jenks SJ, Conway BR, Hor TJ, Williamson RM, McLachlan S, Robertson C, Morling JR, Strachan MWJ, Price JF. Hepatic steatosis and non-alcoholic fatty liver disease are not associated with decline in renal function in people with Type 2 diabetes. Diabet Med 2014; 31:1039-46. [PMID: 24684407 DOI: 10.1111/dme.12456] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 01/18/2014] [Accepted: 03/26/2014] [Indexed: 12/13/2022]
Abstract
AIMS We aimed to determine whether the presence of hepatic steatosis and/or non-alcoholic fatty liver disease was associated with decline in renal function or onset of microalbuminuria in a cohort of people with Type 2 diabetes, including those managed in both primary and secondary care. METHODS Nine hundred and thirty-three patients from the Edinburgh Type 2 Diabetes Study, a cohort of Scottish men and women aged 60-74 years with Type 2 diabetes, underwent assessment for hepatic steatosis by liver ultrasonography 1 year after recruitment. Non-alcoholic fatty liver disease was defined as the presence of steatosis following exclusion of secondary causes of liver disease. Patients were followed for 4 years and decline in renal function was assessed by the change in estimated glomerular filtration rate over time. RESULTS Of the 933 subjects, 530 had hepatic steatosis and, of those with hepatic steatosis, 388 had non-alcoholic fatty liver disease. Neither hepatic steatosis nor non-alcoholic fatty liver disease were significantly associated with rate of decline in renal function, with the mean rate of decline in estimated glomerular filtration rate being -1.55 ml min(-1) 1.73 m(-2) per year for participants with hepatic steatosis compared with -1.84 ml min(-1) 1.73 m(-2) for those without steatosis (P = 0.19). Similar results were obtained when the analysis was restricted to participants with and without non-alcoholic fatty liver disease (-1.44 vs. -1.64 ml min(-1) 1.73 m(-2) per year, respectively; P = 0.44). Additionally, neither hepatic steatosis nor non-alcoholic fatty liver disease were associated with the onset or regression of albuminuria during follow-up (all P ≥ 0.05). CONCLUSIONS The presence of hepatic steatosis/non-alcoholic fatty liver disease was not associated with decline in renal function during a 4-year follow-up in our cohort of older people with Type 2 diabetes.
Collapse
Affiliation(s)
- S J Jenks
- Department of Clinical Biochemistry, Royal Infirmary of Edinburgh, Edinburgh, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Gagin G, Bohon KS, Butensky A, Gates MA, Hu JY, Lafer-Sousa R, Pulumo RL, Qu J, Stoughton CM, Swanbeck SN, Conway BR. Color-detection thresholds in rhesus macaque monkeys and humans. J Vis 2014; 14:12. [PMID: 25027164 DOI: 10.1167/14.8.12] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Macaque monkeys are a model of human color vision. To facilitate linking physiology in monkeys with psychophysics in humans, we directly compared color-detection thresholds in humans and rhesus monkeys. Colors were defined by an equiluminant plane of cone-opponent color space. All subjects were tested on an identical apparatus with a four-alternative forced-choice task. Targets were 2° square, centered 2° from fixation, embedded in luminance noise. Across all subjects, the change in detection thresholds from initial testing to plateau performance (“learning”) was similar for +L − M (red) colors and +M − L (bluish-green) colors. But the extent of learning was higher for +S (lavender) than for −S (yellow-lime); moreover, at plateau performance, the cone contrast at the detection threshold was higher for +S than for −S. These asymmetries may reflect differences in retinal circuitry for S-ON and S-OFF. At plateau performance, the two species also had similar detection thresholds for all colors, although monkeys had shorter reaction times than humans and slightly lower thresholds for colors that modulated L/M cones. We discuss whether these observations, together with previous work showing that monkeys have lower spatial acuity than humans, could be accounted for by selective pressures driving higher chromatic sensitivity at the cost of spatial acuity amongst monkeys, specifically for the more recently evolved L − M mechanism.
Collapse
Affiliation(s)
- Galina Gagin
- Neuroscience Program, Wellesley College, Wellesley, MA, USA
| | | | - Adam Butensky
- Harvard College, Harvard University, Cambridge, MA, USA
| | - Monica A Gates
- Neuroscience Program, Wellesley College, Wellesley, MA, USA
| | - Jiun-Yiing Hu
- Neuroscience Program, Wellesley College, Wellesley, MA, USA
| | | | | | - Jane Qu
- Neuroscience Program, Wellesley College, Wellesley, MA, USA
| | | | | | - Bevil R Conway
- Neuroscience Program, Wellesley College, Wellesley, MA, USADepartment of Neurobiology, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
38
|
Quigley C, Westall C, Wade NJ, Longstaffe K, Cavanagh P, Conway BR. Review: Visual Attention and Consciousness, Nystagmus in Infancy and Childhood, Edgar Rubin and Psychology in Denmark: Figure and Ground, Cognitive Search: Evolution, Algorithms, and the Brain, the Psychology of Visual Art: Eye, Brain and Art. Perception 2014. [DOI: 10.1068/p4306rvw] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Cliodhna Quigley
- Cognitive Neuroscience Laboratory, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
| | - Carol Westall
- University of Toronto and Hospital for Sick Children
| | - Nicholas J Wade
- School of Psychology, University of Dundee, Dundee DD1 4HN, Scotland, UK
| | | | - Patrick Cavanagh
- Laboratoire Psychologie de la Perception, Université Paris Descartes, Centre Biomédical des Saints Pères, 45 rue des Sts Pères, 75006 Paris, France
| | - Bevil R Conway
- Neuroscience Program, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA
| |
Collapse
|
39
|
Hubel DH, Wiesel TN, Yeagle EM, Lafer-Sousa R, Conway BR. Binocular stereoscopy in visual areas V-2, V-3, and V-3A of the macaque monkey. ACTA ACUST UNITED AC 2013; 25:959-71. [PMID: 24122139 DOI: 10.1093/cercor/bht288] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Over 40 years ago, Hubel and Wiesel gave a preliminary report of the first account of cells in monkey cerebral cortex selective for binocular disparity. The cells were located outside of V-1 within a region referred to then as "area 18." A full-length manuscript never followed, because the demarcation of the visual areas within this region had not been fully worked out. Here, we provide a full description of the physiological experiments and identify the locations of the recorded neurons using a contemporary atlas generated by functional magnetic resonance imaging; we also perform an independent analysis of the location of the neurons relative to an anatomical landmark (the base of the lunate sulcus) that is often coincident with the border between V-2 and V-3. Disparity-tuned cells resided not only in V-2, the area now synonymous with area 18, but also in V-3 and probably within V-3A. The recordings showed that the disparity-tuned cells were biased for near disparities, tended to prefer vertical orientations, clustered by disparity preference, and often required stimulation of both eyes to elicit responses, features strongly suggesting a role in stereoscopic depth perception.
Collapse
Affiliation(s)
- David H Hubel
- Department of Neurobiology, Harvard Medical School, The Rockefeller University, Boston, MA 02115, USA and
| | - Torsten N Wiesel
- Department of Neurobiology, Harvard Medical School, The Rockefeller University, Boston, MA 02115, USA and
| | - Erin M Yeagle
- Program in Neuroscience, Wellesley College, Wellesley, MA 02481, USA
| | - Rosa Lafer-Sousa
- Program in Neuroscience, Wellesley College, Wellesley, MA 02481, USA
| | - Bevil R Conway
- Department of Neurobiology, Harvard Medical School, The Rockefeller University, Boston, MA 02115, USA and Program in Neuroscience, Wellesley College, Wellesley, MA 02481, USA
| |
Collapse
|
40
|
Abstract
Neuroscience is increasingly being called upon to address issues within the humanities. We discuss challenges that arise, relating to art and beauty, and provide ideas for a way forward.
Collapse
Affiliation(s)
- Bevil R Conway
- Program in Neuroscience, Wellesley College, Wellesley, Massachusetts, United States of America.
| | | |
Collapse
|
41
|
Conway BR. Doing science making art. Trends Cogn Sci 2012. [DOI: 10.1016/j.tics.2012.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
42
|
Lafer-Sousa R, Liu YO, Lafer-Sousa L, Wiest MC, Conway BR. Color tuning in alert macaque V1 assessed with fMRI and single-unit recording shows a bias toward daylight colors. J Opt Soc Am A Opt Image Sci Vis 2012; 29:657-670. [PMID: 22561924 DOI: 10.1364/josaa.29.000657] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Colors defined by the two intermediate directions in color space, "orange-cyan" and "lime-magenta," elicit the same spatiotemporal average response from the two cardinal chromatic channels in the lateral geniculate nucleus (LGN). While we found LGN functional magnetic resonance imaging (fMRI) responses to these pairs of colors were statistically indistinguishable, primary visual cortex (V1) fMRI responses were stronger to orange-cyan. Moreover, linear combinations of single-cell responses to cone-isolating stimuli of V1 cone-opponent cells also yielded stronger predicted responses to orange-cyan over lime-magenta, suggesting these neurons underlie the fMRI result. These observations are consistent with the hypothesis that V1 recombines LGN signals into "higher-order" mechanisms tuned to noncardinal color directions. In light of work showing that natural images and daylight samples are biased toward orange-cyan, our findings further suggest that V1 is adapted to daylight. V1, especially double-opponent cells, may function to extract spatial information from color boundaries correlated with scene-structure cues, such as shadows lit by ambient blue sky juxtaposed with surfaces reflecting sunshine.
Collapse
Affiliation(s)
- Rosa Lafer-Sousa
- Neuroscience Program, Wellesley College, Wellesley, Massachusetts 02481, USA
| | | | | | | | | |
Collapse
|
43
|
Abstract
Visual area V4 is a midtier cortical area in the ventral visual pathway. It is crucial for visual object recognition and has been a focus of many studies on visual attention. However, there is no unifying view of V4's role in visual processing. Neither is there an understanding of how its role in feature processing interfaces with its role in visual attention. This review captures our current knowledge of V4, largely derived from electrophysiological and imaging studies in the macaque monkey. Based on recent discovery of functionally specific domains in V4, we propose that the unifying function of V4 circuitry is to enable selective extraction of specific functional domain-based networks, whether it be by bottom-up specification of object features or by top-down attentionally driven selection.
Collapse
Affiliation(s)
- Anna W Roe
- Department of Psychology, Vanderbilt University, 301 Wilson Hall, Nashville, TN 37240, USA.
| | | | | | | | | | | | | | | |
Collapse
|
44
|
Abstract
Paintings can be interpreted as the product of the complex neural machinery that translates physical light signals into behavior, experience, and emotion. The brain mechanisms responsible for vision and perception have been sculpted during evolution and further modified by cultural exposure and development. By closely examining artists' paintings and practices, we can discover hints to how the brain works, and achieve insight into the discoveries and inventions of artists and their impact on culture. Here, I focus on an integral aspect of color, color contrast, which poses a challenge for artists: a mark situated on an otherwise blank canvas will appear a different color in the context of the finished painting. How do artists account for this change in color during the production of a painting? In the broader context of neural and philosophical considerations of color, I discuss the practices of three modern masters, Henri Matisse, Paul Cézanne, and Claude Monet, and suggest that the strategies they developed not only capitalized on the neural mechanisms of color, but also influenced the trajectory of western art history.
Collapse
Affiliation(s)
- Bevil R Conway
- Neuroscience Program, Wellesley College, Wellesley, Massachusetts 02481, USA.
| |
Collapse
|
45
|
|
46
|
Nep EI, Conway BR. Grewia Gum 1: Some Mechanical and Swelling Properties of Compact and Film. TROP J PHARM RES 2011. [DOI: 10.4314/tjpr.v10i4.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
47
|
Affiliation(s)
| | | | - Bevil R. Conway
- Department of Neurobiology, Harvard Medical School
- Neuroscience Program, Wellesley College
| |
Collapse
|
48
|
Hendry ER, Worthington T, Conway BR, Lambert PA. Antimicrobial efficacy of eucalyptus oil and 1,8-cineole alone and in combination with chlorhexidine digluconate against microorganisms grown in planktonic and biofilm cultures. J Antimicrob Chemother 2009; 64:1219-25. [PMID: 19837714 DOI: 10.1093/jac/dkp362] [Citation(s) in RCA: 171] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Effective disinfection and antisepsis is pivotal in preventing infections within the healthcare setting. Chlorhexidine digluconate (CHG) is a widely used disinfectant/antiseptic possessing broad-spectrum antimicrobial activity; however, its penetration into bacterial biofilms and human skin is poor. The aim of this study was to investigate the antimicrobial efficacy of crude eucalyptus oil (EO) and its main component 1,8-cineole (a recognized permeation enhancer), alone and in combination with CHG, against a panel of clinically relevant microorganisms grown in planktonic and biofilm cultures. METHODS MICs and minimum bactericidal/fungicidal concentrations were determined for each microorganism grown in suspension and biofilm using microbroth dilution and ATP bioluminescence, respectively. Chequerboard assays were used to determine synergistic, indifferent or antagonistic interactions between CHG and EO or 1,8-cineole. RESULTS Antimicrobial activity was demonstrated by CHG, EO and 1,8-cineole; however, CHG was significantly more active against microorganisms in both planktonic and biofilm modes of growth (P < 0.05). Crude EO was significantly more efficacious against microorganisms grown in suspension compared with 1,8-cineole (P < 0.05). Synergistic activity was demonstrated between CHG and both EO and 1,8-cineole against suspensions of Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Escherichia coli and Candida albicans, and biofilm cultures of MRSA and Pseudomonas aeruginosa. CONCLUSIONS In conclusion, CHG may be combined with either crude EO or its major component 1,8-cineole for enhanced, synergistic antimicrobial activity against a wide range of microorganisms in planktonic and biofilm modes of growth; however, the superior antimicrobial efficacy associated with crude EO alone, compared with 1,8-cineole, favours its combination with CHG.
Collapse
Affiliation(s)
- E R Hendry
- Microbiology, School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK.
| | | | | | | |
Collapse
|
49
|
Lafer-Sousa R, Conway BR. Vision and art: an interdisciplinary approach to neuroscience education. J Undergrad Neurosci Educ 2009; 8:A10-7. [PMID: 23493842 PMCID: PMC3592702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 06/08/2009] [Accepted: 06/09/2009] [Indexed: 11/07/2022]
Abstract
Undergraduate institutions are increasingly adopting neuroscience within their curricula, although it is unclear how best to implement this material given the interdisciplinary nature of the field, which requires knowledge of basic physics, chemistry, biology and psychology. This difficulty is compounded by declines over recent decades in the amount of physics education that students receive in high school, which hinders students' ability to grasp basic principles of neuroscience. Here we discuss our experiences as teacher (BRC) and student (RLS) with an undergraduate course in Vision and Art. The course capitalizes on students' prior interest in visual art to motivate an understanding of the physiological and computational neural processes that underlie vision; our aim is that the learning strategies that students acquire as a result of the format and interdisciplinary approach of the course will increase students' critical thinking skills and benefit them as they pursue other domains of inquiry. The course includes both expert lectures on central themes of vision along with a problem-based learning (PBL) laboratory component that directly engages the students as empirical scientists. We outline the syllabus, the motivation for using PBL, and describe a number of hands-on laboratory exercises, many of which require only inexpensive and readily available equipment. We have developed a website that we hope will facilitate student-driven inquiry beyond the classroom and foster inter-institutional collaboration in this endeavor. We conclude the paper with a discussion of the potential limitations of the course and how to evaluate the success of the course and the website.
Collapse
Affiliation(s)
| | - Bevil R. Conway
- Address correspondence to: Professor Bevil Conway, Neuroscience Program, Wellesley College, 106 Central Street, Wellesley MA, 02418
| |
Collapse
|
50
|
Abstract
Color processing begins with the absorption of light by cone photoreceptors, and progresses through a series of hierarchical stages: Retinal signals carrying color information are transmitted through the lateral geniculate nucleus of the thalamus (LGN) up to the primary visual cortex (V1). From V1, the signals are processed by the second visual area (V2); then by cells located in subcompartments ("globs") within the posterior inferior temporal (PIT) cortex, a brain region that encompasses area V4 and brain regions immediately anterior to V4. Color signals are then processed by regions deep within the inferior temporal (IT) cortex including area TE. As a heuristic, one can consider each of these stages to be involved in constructing a distinct aspect of the color percept. The three cone types are the basis for trichromacy; retinal ganglion cells that respond in an opponent fashion to activation of different cone classes are the basis for color opponency (these "cone-opponent" cells increase their firing rate above baseline to activation of one cone class and decrease their firing rate below baseline to activation of a different cone class); double-opponent neurons in the V1 generate local color contrast and are the building blocks for color constancy; glob cells elaborate the perception of hue; and IT integrates color perception in the context of behavior. Finally, though nothing is known, these signals presumably interface with motor programs and emotional centers of the brain to mediate the widely acknowledged emotional salience of color.
Collapse
Affiliation(s)
- Bevil R Conway
- Neuroscience Program, Wellesley College, Wellesley, Massachusetts, USA.
| |
Collapse
|