Query: mental imagery

title: Unconscious mental imagery
abstract: 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'

title: Visual mental imagery engages the left fusiform gyrus, but not the early visual cortex: a meta analysis of neuroimaging evidence
abstract: The dominant neural model of visual mental imagery (VMI) stipulates that memories from the medial temporal lobe acquire sensory features in early visual areas. However, neurological patients with damage restricted to the occipital cortex typically show perfectly vivid VMI, while more anterior damages extending into the temporal lobe, especially in the left hemisphere, often cause VMI impairments. Here we present two major results reconciling neuroimaging findings in neurotypical subjects with the performance of brain damaged patients: (1) a large scale metaanalysis of 46 fMRI studies, of which 27 investigated specifically visual mental imagery, revealed that VMI engages fronto parietal networks and a well delimited region in the left fusiform gyrus. (2) A Bayesian analysis showing no evidence for imagery related activity in early visual cortices. We propose a revised neural model of VMI that draws inspiration from recent cytoarchitectonic and lesion studies, whereby fronto parietal networks initiate, modulate, and maintain activity in a core temporal network centered on the fusiform imagery node, a high level visual region in the left fusiform gyrus.

title: Screen Time Influences Children's Mental Imagery Performance.
abstract: Mental imagery is a foundational human faculty that depends on active image construction and sensorimotor experiences. However, children now spend a significant proportion of their day engaged with screen media, which (a) provide them with ready made mental images, and (b) constitute a sensory narrowing whereby input is typically focused on the visual and auditory modalities. Accordingly, we test the idea that screen time influences the development of children's mental imagery with a focus on mental image generation and inspection from the visual and haptic domains. In a longitudinal cross lagged panel design, children (n 266) aged between three and nine years were tested at two points in time, 10 months apart. Measures of screen time and mental imagery were employed, alongside a host of control variables including working memory, vocabulary, demographics, device ownership, and age of exposure to screen media. Findings indicate a statistically significant path from screen time at time 1 to mental imagery at time 2, above and beyond the influence of the control variables. These unique findings are discussed in terms of the influence of screen time on mental imagery.

title: Mental Imagery Skills in Competitive Young Athletes and Non athletes
abstract: Mental imagery is a fully immersive multi sensory procedure that associates as numerous senses to create a mental image and process it without the presence of external stimuli. In the sport situation, imagery has been designated as the state in which people imagine themselves while effecting abilities to deal with the forthcoming duty or improve performance. Methodical analyses have revealed that imagery increases performance in motor tasks. This study aims at observing not the vividness of image but the cognitive abilities useful for the inspection, maintenance, generation, and manipulation of dissimilar classes of images, investigating modifications in mental imagery skills in competitive athletes and non athletes. Participants were competitive athletes (n 48) and non athletes (n 48) between the ages of 8 and 13 years (Mage 10.50, SD 1.73) The athletes had a minimum of 5 years of training skill in the sport. They completed the Mental Imagery Test (MIT) Competitive athletes showed higher scores on mental imagery skills than non athletes. The study contributed to increase the exploration in the definite area of mental imagery, supplying an added support for the pluridimensional nature of mental imagery and for its practicality in motor and sport sciences.

title: Assessing the causal role of early visual areas in visual mental imagery
abstract: Pearson on visual mental imagery (Pearson, J. The human imagination: the cognitive neuroscience of visual mental imagery.  (2019))1. The author outlines a model of visual mental imagery based on neuroimaging findings that involves large scale brain networks spanning prefrontal areas to sensory areas, and that highlights the activation of occipital areas during visual mental imagery. Specifically, the model indicates that it is the "sensory and spatial representations of the imagery content" that would be formed in early visual areas. However, individuals with acquired brain damage restricted to the occipital cortex typically have perfectly vivid visual mental imagery. For example, a patient with bilateral strokes in the white matter between the occipital and the temporal cortices2 had severe visual deficits for object form and colour, faces, words and letters but demonstrated perfectly preserved visual mental imagery abilities for these same items3. In addition, people with cortical blindness due to bilateral occipital lesions can experience vivid visual mental images4,5. By contrast, patients with damage ext end ing anteriorly in the temporal lobe, espe cially in the left hemisphere, often find them selves unable to build visual mental images6,7. Where does the discrepancy between the neuroimaging and neuropsy cholo gical findings come from? The neuroimaging results supporting the imagery proposed by Pearson1, whereby fronto parietal networks initiate, modulate and maintain activity in a core left temporal network centred on high level visual regions in the ventral temporal cortex, with no causal role of early visual cortex. There is a reply to this letter by Pearson J. Nat. Rev. Neurosci. https:/doi.org/10.1038/ s41583 020 0349 4 (2020) Paolo Bartolomeo 1 Dounia Hajhajate1, Jianghao Liu1,2 and Alfredo Spagna1,3 1Sorbonne Universite, Inserm U 1127, CNRS UMR 7225, Paris Brain Institute, ICM, Hopital de la Pitie Salpetriere, 75013, Paris, France. 2Dassault Systemes, Velizy Villacoublay, France. 3Department of Psychology, Columbia University in the City of New York, New York, NY, USA 10027.

title: The decentering component of mindfulness reduces reactions to mental imagery.
abstract: Four experiments examined whether reactions to mental imagery can be reduced by the mindfulness component of decentering, that is, the insight that experiences are impermanent mental states. In Experiments 1a, 1b, and 1c, participants vividly imagined an unpleasant autobiographical event or a rewarding food. When instructed to adopt a decentering perspective in comparison to an immersed perspective during imagery, participants experienced less negative affect and fewer cravings to eat. In Experiment 2, participants were exposed to an attractive or a neutral food, and we assessed salivation and eating related imagery. Although imagery did not differ between groups, the attractive food elicited less salivation in decentering relative to control participants. We suggest that decentering can make one's imagery of consuming a food and of reliving of negative experiences less compelling, and thus reduce affective responses to both unpleasant and rewarding imagery, even if the imagery itself is kept active in mind.

title: Does using a foreign language reduce mental imagery?
abstract: In a recent article, Hayakawa and Keysar (2018) propose that mental imagery is less vivid when evoked in a foreign than in a native language. The authors argue that reduced mental imagery could even account for moral foreign language effects, whereby moral choices become more utilitarian when made in a foreign language. Here we demonstrate that Hayakawa and Keysar's (2018) key results are better explained by reduced language comprehension in a foreign language than by less vivid imagery. We argue that the paradigm used in Hayakawa and Keysar (2018) does not provide a satisfactory test of reduced imagery and we discuss an alternative paradigm based on recent experimental developments.

title: Reply to: Assessing the causal role of early visual areas in visual mental imagery
abstract: of visual mental imagery proposing a reverse visual hierarchy starting from prefrontal areas back to sensory areas. I would like to thank Paolo Bartolomeo, Dounia Hajhajate, Jianghao Liu and Alfredo Spagna for their correspondence on our Review (The human imagination: the cogni tive neuro science of visual mental imagery.  (2019))1, which raises some important issues (Assessing the causal role of early visual areas in visual mental imagery.  (2020))2. Neuropsychological work reports that individuals with visual cortex damage can show some imagery like processes without perception3,4, while damage to the temporal lobe can correspond to a lack of imagery/ memory abilities5,6. Further, individuals with aphantasia (no imagery vividness or sensory imagery)7,8 show normal sensory perception (although this is yet to be tested in detail) suggesting a general dissociation, and has been linked to areas outside of early visual cortex9. Based on these reports Bartolomeo et. al. suggest a revision to the reverse visual hierarchy model I described, without a causal role of early visual cortex. Here I outline three reasons why this is not required. Much of the neuropsychological work on imagery is actually correlational, often documented brain injury is correlated with subjective descriptions of imagery loss. Hence, we do not know an individual's imagery abilities prior to the injury. For it to be causal, visual imagery would need to be accurately assessed before and after predefined or 'planned' and controlled damage or interruption to a particular brain region of places, faces, spatial imagery or imagery vividness. To put this another way, visual imagery, like visual perception, is not a unitary process. Different features, colour, form and motion, and their levels of precision are processed across different brain areas and most likely use a range of mechanisms. Further complicating this hierarchical spread is the extreme range of individual differences that naturally exist with imagery, together making cross methodological comparisons and meta analyses difficult.

title: Cortical excitability controls the strength of mental imagery
abstract: Mental imagery provides an essential simulation tool for remembering the past and planning the future, with its strength affecting both cognition and mental health. Research suggests that neural activity spanning prefrontal, parietal, temporal, and visual areas supports the generation of mental images. Exactly how this network controls the strength of visual imagery remains unknown. Here, brain imaging and transcranial magnetic phosphene data show that lower resting activity and excitability levels in early visual cortex (V1 V3) predict stronger sensory imagery. Further, electrically decreasing visual cortex excitability using tDCS increases imagery strength, demonstrating a causative role of visual cortex excitability in controlling visual imagery. Together, these data suggest a neurophysiological mechanism of cortical excitability involved in controlling the strength of mental images.

title: Exploring the neural basis of fear produced by mental imagery: imaginal exposure in individuals fearful of spiders
abstract: Imaginal exposure, i.e. reducing fear using exposure to mental imagery, is a widely used psychological treatment technique for dysfunctional fears. Yet, little is known about its underlying neural mechanisms. The present study examines the neural basis of imaginal exposure using a novel experimental procedure consisting of repeated exposure to flashpoint mental imagery of phobic (spiders) and neutral (gloves) stimuli. Whether the 10 min long imaginal exposure procedure could reduce fear responses was examined one week later. Thirty participants fearful of spiders underwent the experimental procedure. Neural activity was assessed using functional magnetic resonance imaging (session 1) Subjective fear and skin conductance responses were measured throughout the study (sessions 1 and 2) Imaginal exposure evoked intense fear and heightened skin conductance responses, and indicated robust activation in several brain regions, including amygdala, midcingulate cortex and insula. Findings demonstrate that neural activity in fear processing brain areas can be elicited solely by generating a mental image of a phobic stimulus, that is, in the absence of the percept. Relevant for treatment development, results reveal that a single 10 min session of brief exposures to flashpoint mental imagery can lead to lasting reductions in phobic fear at both the subjective and physiological levels. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'