The cognitive neuroscience of mental imagery

Assessing visual mental imagery abilities in cerebral visual impairment

Visual imagery refers to the ability to create voluntary mental representations in the absence of corresponding visual stimuli, and current evidence suggests that it shares common neural mechanisms with visual perception. Cerebral visual impairment (CVI) is a brain-based visual disorder caused by early neurological injury and maldevelopment of central visual processing pathways and areas. Individuals with CVI often present with a complex visual profile, including deficits related to higher-order visual processing. However, the impact of visual maldevelopment on imagery abilities in this population has not been extensively characterized. We used the Vividness of Visual Imagery Questionnaire (VVIQ) to investigate visual imagery abilities in a cohort of CVI participants (n = 25, mean age = 22.48 years ± 12.31 SD) compared to controls with neurotypical vision and development (n = 25, mean age = 22.88 years ± 4.94 SD). We found that individuals with CVI had significantly lower VVIQ scores (mean = 41.84 ± 18.61 SD) than controls (mean = 62.48 ± 13.07 SD), after controlling for age and verbal IQ level. Within the CVI group, visual imagery abilities were not significantly different when separated by baseline visual acuity, gestational status, or co-occurrence of autism spectrum disorder. These results suggest that impaired visual imagery may represent an important feature characterizing the complex visual profile of CVI.

Associations between spatial skills and physics knowledge in primary school: Spatial skills are more important for conceptual scientific knowledge than for factual scientific knowledge

Previous research demonstrates an association between spatial ability and science achievement in primary-school-aged children. However, little is known about the mechanisms driving this relationship. We investigated the associations between children's spatial skills and components of physics learning (factual knowledge vs. conceptual knowledge [predictions and explanations]). Participants (N = 103; mean age = 9.6 years) completed a set of spatial tasks based on the "2 × 2" (intrinsic-extrinsic; static-dynamic) model of spatial cognition. They also participated in a whole-class science lesson about sound, followed by an assessment of science knowledge. After controlling for vocabulary and prior knowledge, spatial ability was not associated with factual knowledge scores. However, spatial skills were significantly associated with predictions and explanations; the association was stronger for explanations than for predictions and was driven by intrinsic-dynamic spatial skills. Findings demonstrate that spatial skills are more important for conceptual scientific knowledge than for factual scientific knowledge and further suggest that spatial intervention studies designed to enhance children's science learning should target intrinsic-dynamic spatial skills.

Mind's eye in the Alzheimer's disease spectrum continuum

BACKGROUND

Visual mental imagery (VMI) is the ability to represent stimuli in the mind without sensory visual input. Previous studies have shown alterations in VMI in Alzheimer's disease (AD). However, VMI has not been investigated in the AD prodromal stage, mild cognitive impairment (MCI).

OBJECTIVE

We investigated VMI ability in mild AD and MCI patients, hypothesizing that VMI ability could be compromised since early disease stage.

METHODS

We enrolled 14 patients with mild AD, 19 amnestic MCI (aMCI), and 23 healthy control subjects (HC), matched for sex, age, and education. VMI assessment included: 1) the O'clock test that allows disentangling the possible role of visuo-perceptual difficulties in the VMI task's performance; 2) a modified version of The Complete Visual Mental Imagery Battery (CVMIB), including tasks evaluating the different VMI processes (generation, maintenance, inspection and transformation).

RESULTS

Results indicated that AD patients performed worse than HC in both perceptual and imaginal tasks of the O'clock test and in all CVMIB's tasks but maintenance. On the contrary, aMCI patients showed difficulties in the generation process and in the imaginal task of the O'clock test.

CONCLUSIONS

Visual images generation, inspection and transformation processes are impaired in mild AD. Moreover, the generation process is selectively impaired in aMCI patients, suggesting that VMI deficits are already present in the prodromal stage of AD.

Seeing and visualizing across the hemispheres

Despite our subjective experience of a largely symmetric visual world, the human brain exhibits varying patterns and degrees of hemispheric asymmetry in distinct processes of visual cognition. This chapter reviews behavioral and neuroimaging evidence from neurotypical individuals and neurological patients, concerning functional asymmetries between the right hemisphere (RH) and the left hemisphere (LH) in visual object processing and mental imagery. Hierarchical perception shows RH preference for global processing and LH preference for local processing. At later stages of visual object processing, RH-based circuits exhibit a relative advantage in terms of perceptual integration, with a subsequent shift toward LH-based circuits for processing at higher conceptual and semantic levels. In voluntary visual mental imagery, circuits in the LH ventral temporal cortex play a pivotal role in transitioning from object meaning to simulated visualization. These hemispheric asymmetries in visual object processing might, in part, be influenced by the overall need to minimize wiring, coupled with the presence of distinct specialized networks within each hemisphere, such as the RH attention networks and the LH language networks. From a broader viewpoint, the evidence examined in this chapter indicates that visual object processing involves the interactions of large-scale cortical circuits within and between the hemispheres.

Transformation but not generation of motor images is disrupted following stimulation over the left inferior parietal lobe

Motor imagery (MI) involves the generation, maintenance, and transformation of motor images; yet, the neural underpinnings of each stage are not well understood. Here, we investigated the role of the left inferior parietal lobe (IPL) in the stages of MI. Healthy participants (N = 20) engaged in a MI task (making judgments about hands presented on a screen; hand laterality judgment task) over two days. Past literature demonstrates the mental rotation of hands in this task involves implicit MI (i.e., where MI occurs spontaneously in the absence of explicit instructions). During the task, active (Day A; 120% resting motor threshold) or sham (Day B; placebo) neuronavigated transcranial magnetic stimulation (TMS) was applied to the left IPL (location determined from past neuroimaging work) on 50% of trials at 250, 500, or 750ms post-stimulus onset, corresponding to different stages of MI. A/B days were randomized across participants. Linear mixed effects (LME) modelling conducted on reaction time and accuracy revealed that longer reaction times were observed when TMS was delivered at 750ms after trial onset, and more greatly for active vs. sham stimulation. This effect was exacerbated for palm-vs. back-view stimuli and for left vs. right hands. Accuracy overall was decreased for active vs. sham stimulation, and to a greater extent for palm-vs. back-view stimuli. Findings suggest that the left IPL is involved in image transformation. Overall this work informs on the neural underpinnings of the stages of MI.

Understanding emotional responses to visual aesthetic artefacts: the SECMEA mechanisms

While many models attempt to explain the aesthetic experience, most limit themselves to art as their focal point and only a few look into why we arrive at a certain response to a visual aesthetic object. This article attempts to offer an extension to the current models by focusing on the mechanisms that induce emotions in relation to visual aesthetic objects. It takes Juslin’s (2013) BRECVEM mechanisms – developed for the domain of music – as its basis. In this article, Juslin’s mechanisms are adapted to the visual domain, resulting in six different emotion-evoking mechanisms: startle reflex, evaluative conditioning, emotional contagion, mental imagery, syntactic expectancy and external appraisal. The authors give an overview of frameworks and empirical studies, demonstrating each of these mechanisms in relation to visual aesthetic objects (visual art as well as advertising and product design). The article’s focus on emotion-inducing mechanisms and existing empirical research provides a basis for improving empirical testing of emotional responses to a broad range of visual aesthetic objects.

Demystifying wine expertise through the lens of imagination: Descriptions and imagery vividness across sensory modalities

For most untrained novices, talking about wine or imagining the smells and flavours of wine is difficult. Wine experts, on the other hand, have been found to have better imagery for wine, and are also more proficient in describing wine. Some scholars have suggested that imagery and language are based on similar underlying processes, but no conclusive evidence has been found regarding mental imagery and language production. In this study, we examined the relationship between imagery and language use in both novices and experts. In an online experiment, wine experts and novices were asked to imagine the colour, smell, taste and mouthfeel of wines in different situations, and were asked to rate the vividness of the imagined experience as well as describe it with words. The results show that experts differ from novices on a number of linguistic measures when describing wine, including the number of words used, the type of words used, the concreteness of those words, and the adjective to noun ratio. Similarly, imagery for wine was more vivid in wine experts compared to novices in the modalities of smell, taste, and mouthfeel, in alignment with previous work. Surprisingly, we found that no single linguistic variable significantly predicted the reported vividness of wine imagery, neither in experts nor in novices. However, the linguistic model predicted imagery vividness better using data from experts compared to novices. Taken together, these findings underscore that imagery and language are different facets of wine cognition.

Repetition and practice. Developing mental training with young violinists: a collaboration

Mental training has been used successfully by professional musicians and athletes, yet rarely applied in pedagogical processes. As research in neuroscience can now explain how it connects to the processes of learning, its application and adaptation in pedagogy can now be explored. The aim of this mixed methods study was to investigate concepts of repetition and practice with mental training, and discuss adaptations for young violinists, to include attention, awareness, and creative musicality. Three exercises were developed with nine students (average age 8). The first involved creation of imagery, followed by physical practice; the second alternated mental imagery with physical practice; the third involved concurrent use of physical practice and mental imagery. Results of the first exercise indicate heightened awareness of technical skill; self-discovery of bow control, speed and distribution, tone production improvements and an ability to sustain longer notes post-mental training (Z = -2.666, p = 0.008 and Z = -2.670, p = 0.008). Observations from the second and third exercises include student experimentation with concepts of musical interpretation, an eagerness to repeat repertoire (≥ 5 times) and increased self-awareness of technical and musical accomplishments. The research suggests that mental training can be adapted for younger learners, that it encourages collaboration in the pedagogical process, and develops student self-awareness of the cognitive and physical processes of violin playing.

Thematic Contents of Mental Imagery are Shaped by Concurrent Task-Irrelevant Music

Imagination plays a key role in evidence-based, cognitive therapies, and recent research highlights that music - a perceptual stimulus imbued with affective and social meaning - can influence some aspects of imagination, such as vividness and emotional tone. However, little is known about music's capability to facilitate specific imagery themes that may be relevant for therapy. Here, we examine whether the quantity and quality (related to themes of affect, social dynamics, and confidence) of people's imagery is affected by the presence of task-irrelevant background music. One hundred participants imagined the continuation of a figure's journey while listening to different musical excerpts or silence. Written reports of imagined journeys underwent linguistic analysis to reveal the number of words belonging to the themes of interest. Bayesian Mixed Effects models revealed that music (vs. silence) led to longer reports and predicted imagery characterised by affect, social dynamics, and confidence. Implications for therapy are discussed.

More implicit and more explicit motor imagery tasks for exploring the mental representation of hands and feet in action

The mental representation of the body in action can be explored using motor imagery (MI) tasks. MI tasks can be allocated along a continuum going from more implicit to more explicit tasks, where the discriminant is the degree of action monitoring required to solve the tasks (which is the awareness of using the mental representation of our own body to monitor our motor imagery). Tasks based on laterality judgments, such as the Hand Laterality Task (HLT) and the Foot Laterality Task (FLT), provide an example of more implicit tasks (i.e., less action monitoring is required). While, an example of a more explicit task is the Mental Motor Chronometry task (MMC) for hands and feet, where individuals are asked to perform or imagine performing movements with their limbs (i.e., more action monitoring is required). In our study, we directly compared hands and feet at all these tasks for the first time, as these body districts have different physical features as well as functions. Fifty-five participants were asked to complete an online version of the HLT and FLT (more implicit measure), and an online version of the MMC task for hands and feet (more explicit measure). The mental representation of hands and feet in action differed only when the degree of action monitoring decreased (HLT ≠ FLT); we observed the presence of biomechanical constraints only for hands. Differently, when the degree of action monitoring increased hands and feet did not show any difference (MMC hands = MMC feet). Our results show the presence of a difference in the mental representation of hands and feet in action that specifically depends on the degree of action monitoring.

Multimodal artistic metaphors: Research on a corpus of Sardinian art

The study aims to define an artistic metaphor and highlight the multimodal properties of metaphors in artistic environments. In this research, an artistic metaphor has a relevant aesthetic purpose and it conveys beauty. Interpreting a metaphor in Sardinian art requires time for contemplation, however the cognitive effort of understanding the meaning of an artistic metaphor is rewarded by the delight of those who contemplate it. This metaphor has some characteristics in common with a visual metaphor but differs from other types of images that have been more extensively analyzed in the literature: it is difficult to establish a specific directionality, and consequently, it is not easy to recognize the target and source domains; the way it is expressed makes its interpretation and classification problematic at times. A proposal is presented in the paper to describe artistic metaphors according to universal macro-categories, inspired by the knowledge of Aristotelian and Kantian categories and by studies in the field of aesthetics: (1) time, (2) space, (3) decontextualization of stereotypes, and (4) fusion of forms. These categories are applied to a corpus of artworks by important artists in Sardinia to show that the visual, tactile, and auditory components of the pictures can boost an effective comprehension of figurative meaning. Results suggest that the multimodality of Sardinian artistic metaphors orients the observer toward original possibilities of learning and stimulates knowledge of the "submerged" wealth of symbols and archetypes that characterize insularity.

Construction of Meta-Thinking Educational Program Based on Mental-Brain Simulation (MTMBS) and Evaluating its Effectiveness on Executive Functions, Emotion Regulation, and Impulsivity in Children With ADHD: A Resting-State Functional MRI Study

OBJECTIVE

The aim of present research was to make a Meta-Thinking educational program based on mental-brain simulation and to evaluate its effectiveness on executive functions, emotion regulation and impulsivity in children with ADHD.

METHODS

The research method was Embedded Design: Embedded Experimental Model. The research sample included 32 children with ADHD who were randomly assigned to two experimental and control groups. The intervention was implemented for eight sessions of 1.5 hr for the experimental group, and fMRI images were taken from them, while the control group didn't receive any treatment. Finally, using semi-structured interviews, coherent information was collected from the parents of the experimental group about the changes made. Data were analyzed with SPSS-24, MAXQDA, fMRIprep, and FSL software.

RESULTS

The Meta-Thinking Educational Program had effect on performance of ADHD children and suppressed brain regions related to DMN.

CONCLUSION

The Implementation of this educational program plays a vital role in improving psychological problems of children with ADHD.

What about "space" is important for episodic memory?

Early cognitive neuroscientific research revealed that the hippocampus is crucial for spatial navigation in rodents, and for autobiographical episodic memory in humans. Researchers quickly linked these streams to propose that the human hippocampus supports memory through its role in representing space, and research on the link between spatial cognition and episodic memory in humans has proliferated over the past several decades. Different researchers apply the term "spatial" in a variety of contexts, however, and it remains unclear what aspect of space may be critical to memory. Similarly, "episodic" has been defined and tested in different ways. Naturalistic assessment of spatial memory and episodic memory (i.e., episodic autobiographical memory) is required to unify the scale and biological relevance in comparisons of spatial and mnemonic processing. Limitations regarding the translation of rodent to human research, human ontogeny, and inter-individual variability require greater consideration in the interpretation of this literature. In this review, we outline the aspects of space that are (and are not) commonly linked to episodic memory, and then we discuss these dimensions through the lens of individual differences in naturalistic autobiographical memory. Future studies should carefully consider which aspect(s) of space are being linked to memory within the context of naturalistic human cognition. This article is categorized under: Psychology > Memory.

Mental imagery of nature induces positive psychological effects

Exposure to natural environments promotes positive psychological effects. Experimental studies on this issue typically have not been able to distinguish the contributions of top-down processes from stimulus-driven bottom-up processing. We tested in an online study whether mental imagery (top-down processing) of restorative natural environments would produce positive psychological effects, as compared with restorative built and non-restorative urban environments. The participants (n = 70) from two countries (Finland and Norway) imagined being present in different environments for 30 s, after which they rated their subjective experiences relating to vividness of imagery, relaxation, emotional arousal, valence (positivity vs. negativity) of emotions, and mental effort. In addition, a psychometric scale measuring vividness of imagination, a scale measuring nature connectedness, and a questionnaire measuring preference of the imagined environments were filled-in. Imagery of natural environments elicited stronger positive emotional valence and more relaxation than imagery of built and urban environments. Nature connectedness and preference moderated these effects, but they did not fully explain the affective benefits of nature. Scores in a psychometric imagery scale were associated in consistent way to the subjective ratings in the imagery task, suggesting that the participants performed attentively and honestly in reporting their subjective experiences. We conclude that top-down factors play a key role in the psychological effects of nature. A practical implication of the findings is that inclusion of natural elements in imagery-based interventions may help to increasing positive affective states.

Vision- and touch-dependent brain correlates of body-related mental processing

In humans, the nature of sensory input influences body-related mental processing. For instance, behavioral differences (e.g., response time) can be found between mental spatial transformations (e.g., mental rotation) of viewed and touched body parts. It can thus be hypothesized that distinct brain activation patterns are associated with such sensory-dependent body-related mental processing. However, direct evidence that the neural correlates of body-related mental processing can be modulated by the nature of the sensory stimuli is still missing. We thus analyzed event-related functional magnetic resonance imaging (fMRI) data from thirty-one healthy participants performing mental rotation of visually- (images) and haptically-presented (plastic) hands. We also dissociated the neural activity related to rotation or task-related performance using models that either regressed out or included the variance associated with response time. Haptically-mediated mental rotation recruited mostly the sensorimotor brain network. Visually-mediated mental rotation led to parieto-occipital activations. In addition, faster mental rotation was associated with sensorimotor activity, while slower mental rotation was associated with parieto-occipital activations. The fMRI results indicated that changing the type of sensory inputs modulates the neural correlates of body-related mental processing. These findings suggest that distinct sensorimotor brain dynamics can be exploited to execute similar tasks depending on the available sensory input. The present study can contribute to a better evaluation of body-related mental processing in experimental and clinical settings.

Imagining interceptions: Eye movements as an online indicator of covert motor processes during motor imagery

The analysis of eye movements during motor imagery has been used to understand the influence of covert motor processes on visual-perceptual activity. There is evidence showing that gaze metrics seem to be affected by motor planning often dependent on the spatial and temporal characteristics of a task. However, previous research has focused on simulated actions toward static targets with limited empirical evidence of how eye movements change in more dynamic environments. The study examined the characteristics of eye movements during motor imagery for an interception task. Twenty-four participants were asked to track a moving target over a computer display and either mentally simulate an interception or rest. The results showed that smooth pursuit variables, such as duration and gain, were lower during motor imagery when compared to passive observation. These findings indicate that motor plans integrate visual-perceptual information based on task demands and that eye movements during imagery reflect such constraint.

Congenital lack and extraordinary ability in object and spatial imagery: An investigation on sub-types of aphantasia and hyperphantasia

Studies that have shown a distinction between object and spatial imagery suggest more than one type of aphantasia and hyperphantasia, yet this has not been systematically investigated in studies on imagery ability extremes. Also, if the involuntary imagery is preserved in aphantasia and how this condition affects other skills is not fully clear. We collected data on spatial and object imagery, retrospective, and prospective memory, face recognition, and sense of direction (SOD), suggesting a distinction between two subtypes of aphantasia/hyperphantasia. Spatial aphantasia is associated with difficulties in visuo-spatial mental imagery and SOD. Instead, in object aphantasia there are difficulties in imaging single items and events - with no mental visualization of objects, out-of-focus, and black-and-white mental images more frequent than expected - in SOD and face recognition. Furthermore, associative involuntary imagery can be spared in aphantasia. The opposite pattern of performance was found in spatial and object hyperphantasia.

Amodal completion and relationalism

Amodal completion is usually characterized as the representation of those parts of the perceived object that we get no sensory stimulation from. In the case of the visual sense modality, for example, amodal completion is the representation of occluded parts of objects we see. I argue that relationalism about perception, the view that perceptual experience is constituted by the relation to the perceived object, cannot give a coherent account of amodal completion. The relationalist has two options: construe the perceptual relation as the relation to the entire perceived object or as the relation to the unoccluded parts of the perceived object. I argue that neither of these options are viable.

Self-perception in anorexia nervosa: When the body becomes an object

OBJECTIVE

Women with anorexia nervosa (AN) act as if they have a larger body, as evidenced in obstacle avoidance tasks, where an allocentric perspective is adopted. This alteration emerges not only when they perform, but also when they imagine movements. However, no previous study has investigated own body centered tasks. As such, in this study we aim at documenting if women with AN show an altered behaviour also when the task requires a first-person perspective.

METHOD

We explored the performance of eleven woman affected by AN compared to eighteen matched controls, in two motor imagery tasks based on a self-frame of reference, the Hand Laterality Task and the Mental Motor Chronometry Task. Moreover, two control tasks relative to visual imagery were administered.

RESULTS

In the Hand Laterality Task, affected participants did not adopt a motor strategy to judge hands laterality (i.e. no biomechanical constraints effect). Crucially, they also showed an altered behavior in the control task. Similarly, they did not show the expected isochrony in the Mental Motor Chronometry Task, when actions pertained the left (but not the right) hand, in absence of any difference in the control task.

CONCLUSIONS

Our findings reveal altered imagery processes in AN. Specifically, affected participants adopt a third-person, rather than a first-person perspective, even when the task requires to imagine their own body in an internal frame of reference. In other words, participants with AN objectify body stimuli. Different mechanisms (i.e., checking behaviour; mirror self-reflection; altered multisensory integration) can explain such an altered imagery in AN.

EXPRESS: Does physical weight alter the mental representation of the body? Evidence from motor imagery in obesity

OBJECTIVE

Obesity is a clinical condition that impacts severely the physical body. However, evidence related to the mental representation of the body in action is scarce. The few available studies only focus on avoiding obstacles, rather than participants imagining their own body.

METHOD

To advance knowledge in this field, we assessed the performance of twenty-two individuals with obesity compared to thirty individuals with a healthy weight in two tasks that implied different motor (more implicit vs. more explicit) imagery strategies. Two tasks were also administered to control for visual imagery skills, to rule out confounding factors. Moreover, we measured body uneasiness, through a standard questionnaire, as body image negativity could impact on other body representation components.

RESULTS

Our findings do not show differences in the motor imagery tasks between individuals with obesity and individuals with healthy weight. On the other hand, some differences emerge in visual imagery skills. Crucially, individuals with obesity did report a higher level of body uneasiness.

CONCLUSIONS

Despite a negative body image and visual imagery differences, obesity per se does not impact on the representation of the body in action. Importantly, this result is independent from the level of awareness required to access the mental representation of the body.

Visual mental imagery: Inside the mind's eyes

What are mental images needed for? A variety of everyday situations calls for us to plan ahead; one of the clever ways our mind prepares and strategizes our next move is through mental simulation. A powerful tool in running these simulations is visual mental imagery, which can be conceived as a way to activate and maintain an internal representation of the to-be-imagined object, giving rise to predictions. Therefore, under normal conditions imagination is primarily an endogenous process, and only more rarely can mental images be activated exogenously, for example, by means of intracerebral stimulation. A large debate is still ongoing regarding the neural substrates supporting mental imagery, with the neuropsychological and neuroimaging literature agreeing in some cases, but not others. This chapter reviews the neuroscientific literature on mental imagery, and attempts to reappraise the neuropsychological and neuroimaging evidence by drawing a model of mental imagery informed by both structural and functional brain data. Overall, the role of regions in the ventral temporal cortex, especially of the left hemisphere, stands out unequivocally as a key substrate in mental imagery.

Mental Imagery Skills in Alcohol-Dependent Subjects and Their Associations With Cognitive Performance: An Exploratory Study During Residential Rehabilitation

People in alcohol-detoxification experience deficits in motor and non-motor functions including cognitive performance. Imagery, the cognitive process of generating visual, auditory or kinesthetic experiences in the mind without the presence of external stimuli, has been little studied in Alcohol Use Disorders (AUD). This pilot study aims to observe the cognitive abilities useful for the inspection, maintenance, generation and manipulation of images in these patients during residential rehabilitation and investigate the relationships with their cognitive performance. Thirty-six subjects who completed the 28-day rehabilitation program for alcohol addiction, completed the Mental Imagery Test (MIT) and Neuropsychological Battery (ENB-2). The global score at MIT did not show pathological scores. The 11.1% of AUD patients showed an impaired global score in the cognitive performance and the 5.7% with scoring at limits of norm. Significant correlations were found between Mental Imagery abilities and ENB-2 subscale and stepwise regression analysis showed the close association between the ability of imagery (Mental Imagery Test) and the overall cognitive performance (ENB-2) in alcohol dependent patients and this relationship is stronger than other cognitive tasks.

Imagining one experience to be another

I can imagine a banana to be a phone receiver. I can also imagine the flapping of my arms to be flying. So it is possible to imagine one thing to be another-at least for some types of 'things'. I will argue that although it is possible to imagine an object to be another object and it is also possible to imagine an activity to be a different activity, one cannot imagine one's present sensory experience to be a different sensory experience with different qualitative character. This claim will have some important consequences beyond the philosophy of imagination, for example, for some accounts of depiction.

Neurofunctional Symmetries and Asymmetries during Voluntary out-of- and within-Body Vivid Imagery Concurrent with Orienting Attention and Visuospatial Detection

We explored whether two visual mental imagery experiences may be differentiated by electroencephalographic (EEG) and performance interactions with concurrent orienting external attention (OEA) to stimulus location and subsequent visuospatial detection. We measured within-subject (N = 10) event-related potential (ERP) changes during out-of-body imagery (OBI)—vivid imagery of a vertical line outside of the head/body—and within-body imagery (WBI)—vivid imagery of the line within one’s own head. Furthermore, we measured ERP changes and line offset Vernier acuity (hyperacuity) performance concurrent with those imagery, compared to baseline detection without imagery. Relative to OEA baseline, OBI yielded larger N200 and P300, whereas WBI yielded larger P50, P100, N400, and P800. Additionally, hyperacuity dropped significantly when concurrent with both imagery types. Partial least squares analysis combined behavioural performance, ERPs, and/or event-related EEG band power (ERBP). For both imagery types, hyperacuity reduction correlated with opposite frontal and occipital ERP amplitude and polarity changes. Furthermore, ERP modulation and ERBP synchronizations for all EEG frequencies correlated inversely with hyperacuity. Dipole Source Localization Analysis revealed unique generators in the left middle temporal gyrus (WBI) and in the right frontal middle gyrus (OBI), whereas the common generators were in the left precuneus and middle occipital cortex (cuneus). Imagery experiences, we conclude, can be identified by symmetric and asymmetric combined neurophysiological-behavioural patterns in interactions with the width of attentional focus.

Unconscious mental imagery

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'.

Exploring the vividness of mental imagery and eidetic imagery in people with intellectual disability (ID) in comparison with typically developing (TD) individuals

Background

Mental imagery (MI) has been described as the “ability to simulate in the mind information that is not currently being perceived by the sense organs” (Moran, 2012, p. 166). The vividness of mental imagery has been defined as the clarity, brightness, or intensity of an image as reported by the individual (Marks, 1973). There are many studies conducted on vividness in typically developing (TD) individuals, however, no attempt has been made either to assess the vividness of mental imagery in people with intellectual disability (ID) or compare it with that of typically developing (TD) adults.

Metods

A vividness of imagery test (comprising a modified version of the Vividness of Visual Imagery Questionnaire 2, (VVIQ-2; Marks, 1995), and two items of the Age Projection Test, (APT; Ahsen, 1988) were administered to participants with mild, moderate, and severe ID. Their performance on the vividness scale was compared with typically developing individuals. Measures for cognitive and adaptive functioning were administered to ascertain the ID level of participants.

Results

The results of this study reveal a non-significant group difference between people with mild ID, moderate ID, and TD on the vividness of mental imagery and eidetic imagery. People with severe ID performed significantly lower than the other three groups.

Conclusion

Despite their cognitive impairment, a non-significant difference between the performance of people with mild and moderate ID and typically developing individuals on imagery vividness scale is noteworthy.

Visual Imagery and Perception Share Neural Representations in the Alpha Frequency Band

To behave adaptively with sufficient flexibility, biological organisms must cognize beyond immediate reaction to a physically present stimulus. For this, humans use visual mental imagery [1, 2], the ability to conjure up a vivid internal experience from memory that stands in for the percept of the stimulus. Visually imagined contents subjectively mimic perceived contents, suggesting that imagery and perception share common neural mechanisms. Using multivariate pattern analysis on human electroencephalography (EEG) data, we compared the oscillatory time courses of mental imagery and perception of objects. We found that representations shared between imagery and perception emerged specifically in the alpha frequency band. These representations were present in posterior, but not anterior, electrodes, suggesting an origin in parieto-occipital cortex. Comparison of the shared representations to computational models using representational similarity analysis revealed a relationship to later layers of deep neural networks trained on object representations, but not auditory or semantic models, suggesting representations of complex visual features as the basis of commonality. Together, our results identify and characterize alpha oscillations as a cortical signature of representations shared between visual mental imagery and perception.

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Perception and imagery share neural representations in the alpha frequency band

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Shared representations stem from parieto-occipital sources

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Modeling suggests contents of shared representations are complex visual features

Constructing calendars in the brain

By studying an enigmatic condition called, "calendar synesthesia", we explored the elusive boundary between perception, visual imagery, and the manner in which we construct an internal mental calendar by mapping time-sequences onto spatial maps. We use a series of demonstrations to establish that these calendars act more like real objects activating sensory pathways rather than purely abstract symbolic descriptions that bear no resemblance to an actual calendar. We propose that the calendar is enshrined in acircuitry involving the hippocampal place-cells and entorhinal grid-cells, which are connected to the angular gyrus (involved with computing sequences) via the inferior longitudinal fasciculus.

The development of body representations in school-aged children

Following the triadic taxonomy, three different body representations do exist, namely the body semantics, the body structural representation and the body schema. The development of these body representations has been widely investigated in toddlers, but several issues remain to be addressed in school age. To assess age- and gender-related changes in different body representations and to investigate the presence of different patterns of interplay between these representations of the body, 90 children (age range: 7-10) and 37 young adults (age range: 18-35) were given tasks assessing the body semantics, the body structural representation and the body schema as well as control tasks. The present results suggested that the body schema, evaluated by means of hand laterality judgments, was still not completely developed in school-aged children, whereas the body structural representation reached an adult-like pattern by the age of 9-10 years. Finally, body semantics was fully developed in school-aged children. These findings were discussed in terms of their theoretical implications, for a better understanding of body representation development; also, implications for clinical assessment of body representation disorders were discussed.

The Role of Visual Experience in Mental Imagery

The mental imagery of participants who became blind early in life (EB participants), participants who became blind later in life (LB participants), and sighted participants was compared in two experiments. In the first experiment, the participants were asked to image common objects and to estimate how far away these objects appeared in their image. In the second experiment, the participants were asked to point to the left and right sides of three objects, imaged at three increasing distances. The LB participants’ performance of the tasks in both experiments was similar to that of the sighted participants, whereas the performance of the EB participants differed. The results reflect the close relationship between the development of visual perception and the properties of images.

Measuring Multisensory Imagery of Wine: the Vividness of Wine Imagery Questionnaire

When we imagine objects or events, we often engage in multisensory mental imagery. Yet, investigations of mental imagery have typically focused on only one sensory modality - vision. One reason for this is that the most common tool for the measurement of imagery, the questionnaire, has been restricted to unimodal ratings of the object. We present a new mental imagery questionnaire that measures multisensory imagery. Specifically, the newly developed Vividness of Wine Imagery Questionnaire (VWIQ) measures mental imagery of wine in the visual, olfactory, and gustatory modalities. Wine is an ideal domain to explore multisensory imagery because wine drinking is a multisensory experience, it involves the neglected chemical senses (smell and taste), and provides the opportunity to explore the effect of experience and expertise on imagery (from wine novices to experts). The VWIQ questionnaire showed high internal consistency and reliability, and correlated with other validated measures of imagery. Overall, the VWIQ may serve as a useful tool to explore mental imagery for researchers, as well as individuals in the wine industry during sommelier training and evaluation of wine professionals.

Endogenously generated gamma-band oscillations in early visual cortex: A neurofeedback study

Human subjects were trained with neurofeedback (NFB) to enhance the power of narrow-band gamma oscillations in circumscribed regions of early visual cortex. To select the region and the oscillation frequency for NFB training, gamma oscillations were induced with locally presented drifting gratings. The source and frequency of these induced oscillations were determined using beamforming methods. During NFB training the power of narrow band gamma oscillations was continuously extracted from this source with online beamforming and converted into the pitch of a tone signal. We found that seven out of ten subjects were able to selectively increase the amplitude of gamma oscillations in the absence of visual stimulation. One subject however failed completely and two subjects succeeded to manipulate the feedback signal by contraction of muscles. In all subjects the attempts to enhance visual gamma oscillations were associated with an increase of beta oscillations over precentral/frontal regions. Only successful subjects exhibited an additional marked increase of theta oscillations over precentral/prefrontal and temporal regions whereas unsuccessful subjects showed an increase of alpha band oscillations over occipital regions. We argue that spatially confined networks in early visual cortex can be entrained to engage in narrow band gamma oscillations not only by visual stimuli but also by top down signals. We interpret the concomitant increase in beta oscillations as indication for an engagement of the fronto-parietal attention network and the increase of theta oscillations as a correlate of imagery. Our finding support the application of NFB in disease conditions associated with impaired gamma synchronization.

The Importance of Amodal Completion in Everyday Perception

Amodal completion is the representation of those parts of the perceived object that we get no sensory stimulation from. In the case of vision, it is the representation of occluded parts of objects we see: When we see a cat behind a picket fence, our perceptual system represents those parts of the cat that are occluded by the picket fence. The aim of this piece is to argue that amodal completion plays a constitutive role in our everyday perception and trace the theoretical consequences of this claim.

fMRI-based Multivariate Pattern Analyses Reveal Imagery Modality and Imagery Content Specific Representations in Primary Somatosensory, Motor and Auditory Cortices

Previous studies have shown that the early visual cortex contains content-specific representations of stimuli during visual imagery, and that these representational patterns of imagery content have a perceptual basis. To date, there is little evidence for the presence of a similar organization in the auditory and tactile domains. Using fMRI-based multivariate pattern analyses we showed that primary somatosensory, auditory, motor, and visual cortices are discriminative for imagery of touch versus sound. In the somatosensory, motor and visual cortices the imagery modality discriminative patterns were similar to perception modality discriminative patterns, suggesting that top-down modulations in these regions rely on similar neural representations as bottom-up perceptual processes. Moreover, we found evidence for content-specific representations of the stimuli during auditory imagery in the primary somatosensory and primary motor cortices. Both the imagined emotions and the imagined identities of the auditory stimuli could be successfully classified in these regions.

The mental simulation of state/psychological verbs in the adolescent brain: An fMRI study

This fMRI study investigated mental simulation of state/psychological and action verbs during adolescence. Sixteen healthy subjects silently read verbs describing a motor scene or not (STIMULUS: motor, state/psychological verbs) and they were explicitly asked to imagine the situation or they performed letter detection preventing them from using simulation (TASK: imagery vs. letter detection). A significant task by stimuli interaction showed that imagery of state/psychological verbs, as compared to action stimuli (controlled by the letter detection) selectively increased activation in the right supramarginal gyrus/rolandic operculum and in the right insula, and decreased activation in the right intraparietal sulcus. We compared these data to those from a group of older participants (Tomasino et al. 2014a). Activation in the left supramarginal gyrus decreased for the latter group (as compared to the present group) for imagery of state/psychological verbs. By contrast, activation in the right superior frontal gyrus decreased for the former group (as compared to the older group) for imagery of state/psychological verbs.

Multimodal mental imagery

When I am looking at my coffee machine that makes funny noises, this is an instance of multisensory perception – I perceive this event by means of both vision and audition. But very often we only receive sensory stimulation from a multisensory event by means of one sense modality, for example, when I hear the noisy coffee machine in the next room, that is, without seeing it. The aim of this paper is to bring together empirical findings about multimodal perception and empirical findings about (visual, auditory, tactile) mental imagery and argue that on occasions like this, we have multimodal mental imagery: perceptual processing in one sense modality (here: vision) that is triggered by sensory stimulation in another sense modality (here: audition). Multimodal mental imagery is not a rare and obscure phenomenon. The vast majority of what we perceive are multisensory events: events that can be perceived in more than one sense modality – like the noisy coffee machine. And most of the time we are only acquainted with these multisensory events via a subset of the sense modalities involved – all the other aspects of these multisensory events are represented by means of multisensory mental imagery. This means that multisensory mental imagery is a crucial element of almost all instances of everyday perception.

Sensory Substitution and Multimodal Mental Imagery

Many philosophers use findings about sensory substitution devices in the grand debate about how we should individuate the senses. The big question is this: Is "vision" assisted by (tactile) sensory substitution really vision? Or is it tactile perception? Or some sui generis novel form of perception? My claim is that sensory substitution assisted "vision" is neither vision nor tactile perception, because it is not perception at all. It is mental imagery: visual mental imagery triggered by tactile sensory stimulation. But it is a special form of mental imagery that is triggered by corresponding sensory stimulation in a different sense modality, which I call "multimodal mental imagery."

Microdream neurophenomenology

Nightly transitions into sleep are usually uneventful and transpire in the blink of an eye. But in the laboratory these transitions afford a unique view of how experience is transformed from the perceptually grounded consciousness of wakefulness to the hallucinatory simulations of dreaming. The present review considers imagery in the sleep-onset transition-"microdreams" in particular-as an alternative object of study to dreaming as traditionally studied in the sleep lab. A focus on microdream phenomenology has thus far proven fruitful in preliminary efforts to (i) develop a classification for dreaming's core phenomenology (the "oneiragogic spectrum"), (ii) establish a structure for assessing dreaming's multiple memory inputs ("multi-temporal memory sources"), (iii) further Silberer's project for classifying sleep-onset images in relation to waking cognition by revealing two new imagery types ("autosensory imagery," "exosensory imagery"), and (iv) embed a potential understanding of microdreaming processes in a larger explanatory framework ("multisensory integration approach"). Such efforts may help resolve outstanding questions about dream neurophysiology and dreaming's role in memory consolidation during sleep but may also advance discovery in the neuroscience of consciousness more broadly.

The impact of ageing and gender on visual mental imagery processes: A study of performance on tasks from the Complete Visual Mental Imagery Battery (CVMIB)

In this study we aim to evaluate the impact of ageing and gender on different visual mental imagery processes. Two hundred and fifty-one participants (130 women and 121 men; age range = 18-77 years) were given an extensive neuropsychological battery including tasks probing the generation, maintenance, inspection, and transformation of visual mental images (Complete Visual Mental Imagery Battery, CVMIB). Our results show that all mental imagery processes with the exception of the maintenance are affected by ageing, suggesting that other deficits, such as working memory deficits, could account for this effect. However, the analysis of the transformation process, investigated in terms of mental rotation and mental folding skills, shows a steeper decline in mental rotation, suggesting that age could affect rigid transformations of objects and spare non-rigid transformations. Our study also adds to previous ones in showing gender differences favoring men across the lifespan in the transformation process, and, interestingly, it shows a steeper decline in men than in women in inspecting mental images, which could partially account for the mixed results about the effect of ageing on this specific process. We also discuss the possibility to introduce the CVMIB in clinical assessment in the context of theoretical models of mental imagery.

Fundamentally Distributed Information Processing Integrates the Motor Network into the Mental Workspace during Mental Rotation

The manipulation of mental representations in the human brain appears to share similarities with the physical manipulation of real-world objects. In particular, some neuroimaging studies have found increased activity in motor regions during mental rotation, suggesting that mental and physical operations may involve overlapping neural populations. Does the motor network contribute information processing to mental rotation? If so, does it play a similar computational role in both mental and manual rotation, and how does it communicate with the wider network of areas involved in the mental workspace? Here we used multivariate methods and fMRI to study 24 participants as they mentally rotated 3-D objects or manually rotated their hands in one of four directions. We find that information processing related to mental rotations is distributed widely among many cortical and subcortical regions, that the motor network becomes tightly integrated into a wider mental workspace network during mental rotation, and that motor network activity during mental rotation only partially resembles that involved in manual rotation. Additionally, these findings provide evidence that the mental workspace is organized as a distributed core network that dynamically recruits specialized subnetworks for specific tasks as needed.

Effects of Stimulus Type and Strategy on Mental Rotation Network: An Activation Likelihood Estimation Meta-Analysis

We can predict how an object would look like if we were to see it from different viewpoints. The brain network governing mental rotation (MR) has been studied using a variety of stimuli and tasks instructions. By using activation likelihood estimation (ALE) meta-analysis we tested whether different MR networks can be modulated by the type of stimulus (body vs. non-body parts) or by the type of tasks instructions (motor imagery-based vs. non-motor imagery-based MR instructions). Testing for the bodily and non-bodily stimulus axis revealed a bilateral sensorimotor activation for bodily-related as compared to non-bodily-related stimuli and a posterior right lateralized activation for non-bodily-related as compared to bodily-related stimuli. A top-down modulation of the network was exerted by the MR tasks instructions with a bilateral (preferentially sensorimotor left) network for motor imagery- vs. non-motor imagery-based MR instructions and the latter activating a preferentially posterior right occipito-temporal-parietal network. The present quantitative meta-analysis summarizes and amends previous descriptions of the brain network related to MR and shows how it is modulated by top-down and bottom-up experimental factors.

Hallucinations and mental imagery demonstrate top-down effects on visual perception

In this commentary, we present two examples where perception is not only influenced by, but also in fact driven by, top-down effects: hallucinations and mental imagery. Crucially, both examples avoid all six of the potential confounds that Firestone & Scholl (F&S) raised as arguments against previous studies claiming to demonstrate the influence of top-down effects on perception.

Differential Neural Processing during Motor Imagery of Daily Activities in Chronic Low Back Pain Patients

Chronic low back pain (chronic LBP) is both debilitating for patients but also a major burden on the health care system. Previous studies reported various maladaptive structural and functional changes among chronic LBP patients on spine- and supraspinal levels including behavioral alterations. However, evidence for cortical reorganization in the sensorimotor system of chronic LBP patients is scarce. Motor Imagery (MI) is suitable for investigating the cortical sensorimotor network as it serves as a proxy for motor execution. Our aim was to investigate differential MI-driven cortical processing in chronic LBP compared to healthy controls (HC) by means of functional magnetic resonance imaging (fMRI). Twenty-nine subjects (15 chronic LBP patients, 14 HC) were included in the current study. MI stimuli consisted of randomly presented video clips showing every-day activities involving different whole-body movements as well as walking on even ground and walking downstairs and upstairs. Guided by the video clips, subjects had to perform MI of these activities, subsequently rating the vividness of their MI performance. Brain activity analysis revealed that chronic LBP patients exhibited significantly reduced activity compared to HC subjects in MI-related brain regions, namely the left supplementary motor area and right superior temporal sulcus. Furthermore, psycho-physiological-interaction analysis yielded significantly enhanced functional connectivity (FC) between various MI-associated brain regions in chronic LBP patients indicating diffuse and non-specific changes in FC. Current results demonstrate initial findings about differences in MI-driven cortical processing in chronic LBP pointing towards reorganization processes in the sensorimotor network.