scholarly journals Unconscious mental imagery

2020 ◽  
Vol 376 (1817) ◽  
pp. 20190689 ◽  
Author(s):  
Bence Nanay
Keyword(s):  
Mental Imagery ◽  
Conscious Experience ◽  
Theme Issue ◽  
External Stimulation ◽  
The Subject ◽  
Experiential State

Historically, mental imagery has been defined as an experiential state—as something necessarily conscious. But most behavioural or neuroimaging experiments on mental imagery—including the most famous ones—do not actually take the conscious experience of the subject into consideration. Further, recent research highlights that there are very few behavioural or neural differences between conscious and unconscious mental imagery. I argue that treating mental imagery as not necessarily conscious (as potentially unconscious) would bring much needed explanatory unification to mental imagery research. It would also help us to reassess some of the recent aphantasia findings inasmuch as at least some subjects with aphantasia would be best described as having unconscious mental imagery. This article is part of the theme issue ‘Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation’.

scholarly journals Hallucinations on demand: the utility of experimentally induced phenomena in hallucination research

2020 ◽  
Vol 376 (1817) ◽  
pp. 20200233
Author(s):  
Sebastian Rogers ◽  
Rebecca Keogh ◽  
Joel Pearson
Keyword(s):  
Cognitive Neuroscience ◽  
Conscious Experience ◽  
Sensory Information ◽  
Research Progress ◽  
Theme Issue ◽  
External Stimulation ◽  
On Demand ◽  
Visual Phenomena ◽  
Laboratory Models ◽  
Experimentally Induced

Despite the desire to delve deeper into hallucinations of all types, methodological obstacles have frustrated development of more rigorous quantitative experimental techniques, thereby hampering research progress. Here, we discuss these obstacles and, with reference to visual phenomena, argue that experimentally induced phenomena (e.g. hallucinations induced by flickering light and classical conditioning) can bring hallucinations within reach of more objective behavioural and neural measurement. Expanding the scope of hallucination research raises questions about which phenomena qualify as hallucinations, and how to identify phenomena suitable for use as laboratory models of hallucination. Due to the ambiguity inherent in current hallucination definitions, we suggest that the utility of phenomena for use as laboratory hallucination models should be represented on a continuous spectrum, where suitability varies with the degree to which external sensory information constrains conscious experience. We suggest that existing strategies that group pathological hallucinations into meaningful subtypes based on hallucination characteristics (including phenomenology, disorder and neural activity) can guide extrapolation from hallucination models to other hallucinatory phenomena. Using a spectrum of phenomena to guide scientific hallucination research should help unite the historically separate fields of psychophysics, cognitive neuroscience and clinical research to better understand and treat hallucinations, and inform models of consciousness. This article is part of the theme issue ‘Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation’.

scholarly journals Attention driven phantom vision: measuring the sensory strength of attentional templates and their relation to visual mental imagery and aphantasia

2020 ◽  
Vol 376 (1817) ◽  
pp. 20190688 ◽  
Author(s):  
Rebecca Keogh ◽  
Joel Pearson
Keyword(s):  
Mental Imagery ◽  
Binocular Rivalry ◽  
Visual Imagery ◽  
Special Population ◽  
Simulation Tool ◽  
Theme Issue ◽  
External Stimulation ◽  
Feature Based ◽  
Future Object ◽  
The Relationship

When we search for an object in an array or anticipate attending to a future object, we create an ‘attentional template' of the object. The definitions of attentional templates and visual imagery share many similarities as well as many of the same neural characteristics. However, the phenomenology of these attentional templates and their neural similarities to visual imagery and perception are rarely, if ever discussed. Here, we investigate the relationship between these two forms of non-retinal phantom vision through the use of the binocular rivalry technique, which allows us to measure the sensory strength of attentional templates in the absence of concurrent perceptual stimuli. We find that attentional templates correlate with both feature-based attention and visual imagery. Attentional templates, like imagery, were significantly disrupted by the presence of irrelevant visual stimuli, while feature-based attention was not. We also found that a special population who lack the ability to visualize (aphantasia), showed evidence of feature-based attention when measured using the binocular rivalry paradigm, but not attentional templates. Taken together, these data suggest functional similarities between attentional templates and visual imagery, advancing the theory of visual imagery as a general simulation tool used across cognition. This article is part of the theme issue ‘Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation’.

scholarly journals Hallucination, imagery, dreaming: reassembling stimulus-independent perceptions based on Edmund Parish's classic misperception framework

2020 ◽  
Vol 376 (1817) ◽  
pp. 20190701 ◽  
Author(s):  
Flavie Waters ◽  
Joseph M. Barnby ◽  
Jan Dirk Blom
Keyword(s):  
Mental Imagery ◽  
Brain Function ◽  
Human Perception ◽  
Future Research ◽  
Theme Issue ◽  
External Stimulation ◽  
Common Framework ◽  
Research Findings ◽  
Computational Sciences ◽  
Similarities And Differences

Within the broad field of human perception lies the category of stimulus-independent perceptions, which draws together experiences such as hallucinations, mental imagery and dreams. Traditional divisions between medical and psychological sciences have contributed to these experiences being investigated separately. This review aims to examine their similarities and differences at the levels of phenomenology and underlying brain function and thus reassemble them within a common framework. Using Edmund Parish's historical work as a guiding tool and the latest research findings in the cognitive, clinical and computational sciences, we consider how different perspectives may be reconciled and help generate novel hypotheses for future research. This article is part of the theme issue ‘Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation’.

scholarly journals Double Vision, Phosphenes and Afterimages

2020 ◽  
Vol 16 (1) ◽  
pp. 5-32
Author(s):  
Işık Sarıhan
Keyword(s):  
Conscious Experience ◽  
Theoretical Framework ◽  
Double Vision ◽  
Phenomenal Experience ◽  
The World ◽  
The Subject ◽  
The Mind

Pure representationalism or intentionalism for phenomenal experience is the theory that all introspectible qualitative aspects of a conscious experience can be analyzed as qualities that the experience non-conceptually represents the world to have. Some philosophers have argued that experiences such as afterimages, phosphenes and double vision are counterexamples to the representationalist theory, claiming that they are non- representational states or have non-representational aspects, and they are better explained in a qualia-theoretical framework. I argue that these states are fully representational states of a certain kind, which I call “automatically non-endorsed representations”, experiential states the veridicality of which we are almost never committed to, and which do not trigger explicit belief or disbelief in the mind of the subject. By investigating descriptive accounts of afterimages by two qualia theorists, I speculate that the mistaken claims of some anti-representationalists might be rooted in confusing two senses of the term “seeming”.

scholarly journals Challenges for theories of consciousness: seeing or knowing, the missing ingredient and how to deal with panpsychism

2018 ◽  
Vol 373 (1755) ◽  
pp. 20170344 ◽  
Author(s):  
Victor A. F. Lamme
Keyword(s):  
Conscious Experience ◽  
Complex Phenomenon ◽  
Significant Progress ◽  
Theme Issue ◽  
Perceptual Consciousness ◽  
Knowing That ◽  
Cognitive Access ◽  
Visual Consciousness ◽  
New Challenges ◽  
Made In

Significant progress has been made in the study of consciousness. Promising theories have been developed and a wealth of experimental data has been generated, both guiding us towards a better understanding of this complex phenomenon. However, new challenges have surfaced. Is visual consciousness about the seeing or the knowing that you see? Controversy about whether the conscious experience is better explained by theories that focus on phenomenal (P-consciousness) or cognitive aspects (A-consciousness) remains, and the debate seems to reach a stalemate. Can we ever resolve this? A further challenge is that many theories of consciousness seem to endorse high degrees of panpsychism—the notion that all beings or even lifeless objects have conscious experience. Should we accept this, or does it imply that these theories require further ingredients that would put a lower bound on beings or devices that have conscious experience? If so, what could these ‘missing ingredients’ be? These challenges are discussed, and potential solutions are offered. This article is part of the theme issue ‘Perceptual consciousness and cognitive access’.

scholarly journals Dynamic simulations of many-body electrostatic self-assembly

2018 ◽  
Vol 376 (2115) ◽  
pp. 20170143 ◽  
Author(s):  
Eric B. Lindgren ◽  
Benjamin Stamm ◽  
Yvon Maday ◽  
Elena Besley ◽  
A. J. Stace
Keyword(s):  
Self Assembly ◽  
Experimental Studies ◽  
Charged Particles ◽  
Theoretical Chemistry ◽  
Many Body ◽  
Single Particles ◽  
Theme Issue ◽  
Dynamic Simulations ◽  
The Subject ◽  
Small Clusters

Two experimental studies relating to electrostatic self-assembly have been the subject of dynamic computer simulations, where the consequences of changing the charge and the dielectric constant of the materials concerned have been explored. One series of calculations relates to experiments on the assembly of polymer particles that have been subjected to tribocharging and the simulations successfully reproduce many of the observed patterns of behaviour. A second study explores events observed following collisions between single particles and small clusters composed of charged particles derived from a metal oxide composite. As before, observations recorded during the course of the experiments are reproduced by the calculations. One study in particular reveals how particle polarizability can influence the assembly process. This article is part of the theme issue ‘Modern theoretical chemistry’.

scholarly journals The offline stream of conscious representations

2018 ◽  
Vol 373 (1755) ◽  
pp. 20170349 ◽  
Author(s):  
Claire Sergent
Keyword(s):  
Working Memory ◽  
Sensory Processing ◽  
Psychological Refractory Period ◽  
Conscious Experience ◽  
Iconic Memory ◽  
External Stimulation ◽  
Capacity Limitations ◽  
Sequence Of Events ◽  
Cognitive Access ◽  
Conscious Processing

When do we become conscious of a stimulus after its presentation? We would all agree that this necessarily takes time and that it is not instantaneous. Here, I would like to propose not only that conscious access is delayed relative to the external stimulation, but also that it can flexibly desynchronize from external stimulation; it can process some information ‘offline’, if and when it becomes relevant. Thus, in contrast with initial sensory processing, conscious experience might not strictly follow the sequence of events in the environment. In this article, I will review gathering evidence in favour of this proposition. I will argue that it offers a coherent framework for explaining a great variety of observations in the domain of perception, sensory memory and working memory: the psychological refractory period, the attentional blink, post-dictive phenomena, iconic memory, latent working memory and the newly described retro-perception phenomenon. I will integrate this proposition to the global neuronal workspace model and consider possible underlying brain mechanisms. Finally, I will argue that this capacity to process information ‘offline’ might have made conscious processing evolutionarily advantageous in spite of its sluggishness and capacity limitations. This article is part of the theme issue ‘Perceptual consciousness and cognitive access’.

scholarly journals Offline perception: an introduction

2020 ◽  
Vol 376 (1817) ◽  
pp. 20190686
Author(s):  
Peter Fazekas ◽  
Bence Nanay ◽  
Joel Pearson
Keyword(s):  
State Of The Art ◽  
Theme Issue ◽  
Research Directions ◽  
External Stimulation ◽  
Theoretical Approaches ◽  
Similarities And Differences

Experiences that are self-generated and independent of sensory stimulations permeate our whole life. This theme issue examines their similarities and differences, systematizes the literature from an integrative perspective, critically discusses state-of-the-art empirical findings and proposes new theoretical approaches. The aim of the theme issue is to foster interaction between the different disciplines and research directions involved and to explore the prospects of a unificatory account of offline perception in general. This article is part of the theme issue ‘Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation’.

scholarly journals The periodic law of the chemical elements: ‘ The new system of atomic weights which renders evident the analogies which exist between bodies ' []

2020 ◽  
Vol 378 (2180) ◽  
pp. 20190537
Author(s):  
Peter P. Edwards ◽  
Russell G. Egdell ◽  
Dieter Fenske ◽  
Benzhen Yao
Keyword(s):  
Chemical Elements ◽  
Chemical Society ◽  
Special Issue ◽  
Theme Issue ◽  
Great Scientist ◽  
Periodic Law ◽  
The Subject ◽  
Remarkable Advance ◽  
New System ◽  
Natural Relation

The historical roots, the discovery and the modern relevance of Dmitri Mendeleev's remarkable advance have been the subject of numerous scholarly works. Here, with a brief overview, we hope to provide a link into the contents of this special issue honouring the great scientist. Mendeleev's advance, announced in March 1869, as he put it in 1889, to the ‘… then youthful Russian Chemical Society… ’, first set out the very basis of the periodic law of the chemical elements, the natural relation between the properties of the elements and their atomic weights. This was, and still is, the centrepiece of a historical journey for chemistry to today's position as a pre-eminent science. This article is part of the theme issue ‘Mendeleev and the periodic table'.

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