Designing cutting-edge technology to understand human cognition
We’ve all experienced it.
A terrifying monster is chasing you. You try to run but your legs won’t work. It’s as if you’re trudging through a thick swamp. You can’t escape. Fear and horror fill your mind and you wake with a start.
It was a nightmare.
Although nearly everyone has the occasional nightmare, around 2–6% of the US adult population experiences chronic nightmares, termed nightmare disorder. Sometimes rooted in past trauma, nightmares are defined by a terrifying loss of control, which causes the dreamer to awaken out of fright. The disruption to sleep caused by nightmare disorder can have profound long-term effects, contributing to a vicious cycle of sleep deprivation and deteriorating mental health.
At the CMAC, we are utilizing a computational neuroscience approach to deepen our understanding of the function of dreams and nightmares in human cognition. We hope to develop novel therapies for nightmare disorder. Our projects on dreams and nightmares range from virtual reality therapy for nightmare disorder to a computational model of dreams and religious cognition.
Imagery Rehearsal Therapy
The gold standard treatment for reducing the distress associated with recurrent nightmares is Imagery Rehearsal Therapy (IRT). IRT is also the basis for our virtual reality therapy. At series of sessions over multiple weeks, participants practice mentally replacing nightmare imagery with less frightening images.
This practice strengthens their imagery control — the cognitive capacity to fluently transform and manipulate mental images. With their strengthened imagery control, participants are able to “de-fang” their nightmares and avoid the distressing feelings that would otherwise disturb their sleep.
Unfortunately, IRT is taxing and outright inaccessible to some people. Participants must be willing and able to imaging troubling and sometimes traumatizing imagery, which risk re-traumatizing people suffering from PTSD. Moreover, younger and older populations — who are more likely to experience nightmare disorder — often lack the cognitive control required to visualize and manipulate mental images. IRT also requires an extensive time commitment.
However, virtual reality technology has opened the door for people to practice IRT in a more tailored and controlled environment.
Exploring virtual reality as therapy for nightmare disorder
Virtual reality (VR) allows for the creation of lifelike settings that are immersive for patients and easier for researchers to manipulate. Studies have shown that VR can help diagnose and treat various neurological disorders such as depression, PTSD, and phobias. Insurance is beginning to cover these therapies. VR imagery can be very intense and realistic, creating images even more vivid than those created by the imagination.
Rendever is a company which designs headsets catered to older users who may have difficulty remembering or imagining. These headsets provide customizable reminiscence therapy, allowing users to revisit places from the past. This can serve as a potent therapy for those suffering from memory loss by allowing them to re-experience visiting places that they can no longer remember.
Another benefit of VR is that it allows images to be controlled: a use or helper can switch off images and scenarios if the user becomes too distressed. VR allows users to use external controls, such as a hand-held controller, to manipulate images, rather than relying on their own imaginative control.
For people with PTSD, the vivid details from the VR headsets can make them feel immersed and physically returned to the traumatic event. But now they have control over the experience and can ensure a better outcome. While this is often a harrowing experience, many report feeling better having re-experienced the event in such a vivid way.
The ability to externally control the VR images enables users and therapists to create safer, more controlled environments and reduce the risk of re-traumatizing patients.
Subduing the dreams that keep us awake
Led by CMAC co-founder and neuroscientist Dr. Patrick McNamara, our ReScript team uses Oculus Rift VR technology to combat nightmare disorder. Individuals use a joystick and gesture controls to transform frightening images into friendlier images, gradually increasing their control over distressing nightmare imagery.
In an interview with Medical Xpress, McNamara explained the pilot study. 19 participants who reported having frequent nightmares visited McNamara’s lab twice a week to use the Oculus headset and its joystick controls to alter scary visuals and create new narratives. McNamara explained, “We think that they learn these imagery control skills and then over a couple of weeks, those skills get transferred from their conscious state into their dream state.”
The results, published in the journal Dreaming, suggested that ReScript use reduces anxiety, lessens, nightmare distress, and produces less daytime nightmare effects for users suffering from nightmare disorder.
ReScript expands therapy to those who struggle with imagery control, such as children and older adults. McNamara encourages, “The most exciting thing about this is the potential to bring this to kids suffering from nightmares,” which will ultimately help to prevent future psychosis and hopefully save lives.
Studying the formal properties of nightmare images
ReScript therapy harmonizes with recent research on nightmares that suggests that feelings of control and mastery are key to combating nightmare disorder.
Patrick McNamara led another CMAC team to create a system dynamics model of nightmare symptomology named the Disturbed Dreaming Model (DDM). This model builds upon Levin and Nielsen’s Affective Network Dysfunction (AND) model of disturbed dreaming.
The Affective Network Dysfunction (AND) framework
According to the AND framework, nightmare imagery is not only “scary” but emotionally-loaded and attention-grabbing. These are described by five imagery characteristics: dominance, arousal, valence, imagery vividness, and imagery presence.
Dream images are experienced as real (image presence) and finely detailed (imagery vividness). Nightmare imagery demands the attention of the dreamer (dominance), causes the dreamer to enter a vigilant state (arousal), and elicits a strong emotional reaction (valence).
The Disturbed Dreaming Model (DDM)
According to our Disturbed Dreaming Model (the DDM), normal frightening dreams are a healthy mechanism for reducing distress caused by stressful everyday events. By recontextualising these stressful events and making new connections to other memories, frightening dreams ultimately help to reduce the distress caused by such events.
Nightmares are a dysfunction of this process wherein stressful memories are not successfully recontextualized, heightening rather than reducing fear and distress. Negative valence, high arousal, and high dominance are crucial for determining how frightening a dream is and, consequently, how likely the normal fear extinction process is to succeed.
ReScript therapy works because it increases a subject’s sense of control over these sorts of images. CMAC hopes to use the DDM to develop personalized treatment alternatives for individuals suffering from nightmare disorder.
A neurocomputational theory of nightmares
Using the AND framework and our DDM, we created a computational model of the qualitative effects of imagery in nightmare disorders. We based this model on data collected during a 4-week intervention trial using VR therapy. Participants used manual controls attached to a VR headset to adjust valence, dominance, and arousal properties of images until they felt that the images were less threatening.
From this, McNamara identified the varying influence of these imagery characteristics on nightmare intensity, nightmare-related anxiety, and the daytime functional effects of nightmares in people with nightmare disorder.
“We designed the treatment so that it can be adjusted and individualized,” McNamara assures. We hope to use this neurocomputational model of nightmares in the future to customize ReScript treatments to each patient according to their individual sensitivity to different image characteristics.
The next step is to design a double-blind clinical trial which will verify the effects of VR therapy and rule out placebo effects. One group of participants would use VR therapy while the other would undergo standard imagery rehearsal therapy.
Finally, we seek to use studies like this to increase our understanding of the inner workings of nightmares. What determines when a frightening dream becomes a nightmare? Can nightmares and dreams influence how we feel toward people and ideas in waking life?
Building an individualized model of nightmares
Currently, we are designing a survey which will provide the data for calibrating the neurocomputational model of nightmares previously described. The survey is focused on older people who have chronic nightmares and will contain questions related to their cognitive, psychological, religious, and dream experiences.
Using this data, we will calibrate the model to predict the threshold for when a healthy bad dream turns into a nightmare, depending on each dreamer’s personal characteristics.
To our knowledge, there are no studies of the cognitive mechanisms of nightmare disorder among older adults (aged 65 years and older). Nightmare disorder remains under-diagnosed and under-studied, despite the significant clinical dysfunction associated with it.
Calibrating the model with real-world data will improve its accuracy in making predictions for who might benefit from therapy and what approach the therapy should take. The model will also allow therapists to virtually experiment with nightmare mechanisms and treatment alternatives to make a better-informed decision about what to recommend to patients.
Cognition of supernatural agents in dreams
We are also building a computational model which explores how dreaming influences our relational attachments, particularly to religious or supernatural figures. Cognitive Neuroscience of Religious Cognition (CNRC) is designing a simulation of the REM-Theta system to model how sleep and dreaming affect people’s religious cognitions.
Do dreams influence how people relate to others, such as their friends, family, and co-workers? Do they similarly influence our relations with God or other supernatural beings?
Generously funded by the John Templeton Foundation, our project, REM-Theta Activity & Supernatural Agent Cognitions in Dreams, will asses the relationship between nightly REM sleep and participants’ sense of attachment to friends, family, as well as to God and other supernatural agents. Daily questionnaires will ask participants about their attachments to partners and friends, their mood, other psychological characteristics, and their religious beliefs. A simple EEG headband will record nightly somnographs of their sleep cycles.
This data will allow us to create a preliminary computational simulation of the REM-Theta system in an individual agent. Using this individual model, we will create an artificial society populated by multiple AI agents who interact around religious cognition. We hope to improve our understanding of the cognitive neuroscience behind dreams and religious cognition.
Virtual Reality for Nightmare Disorder is just the beginning for CMAC. Lead by Dr. Patrick McNamara’s expertise, we are planning more projects exploring dreams, nightmares, and human cognition.
We approach nightmare disorder holistically, seeking to understand the underlying causes and mental mechanisms that cause nightmares and to develop practical therapies and diagnostic methods for people who struggle with chronic nightmares. We hope that our research will improve the lives of those with nightmare disorder, especially those who are unable to undergo IRT. Foremost among this group are children and older persons, who often struggle with imagery control and have higher rates of nightmare disorder.
Our cutting-edge approach incorporates cognitive neuroscience and computational models to shed light on the inner workings of the human mind.
Jessie is a student in the M.A. program in philosophy at Boston College. She began her graduate studies after graduating magna cum laude from the University of Notre Dame, where she studied philosophy and Russian. Her primary interests are existentialism, Russian philosophy, and the question of what a “self” is. She enjoys reading and writing about philosophy, theology, and literature.