Category: Cognitive science

Categories
Cognitive science Science

Brain stimulation tests give hope for autism treatment

Research breakthrough highlights cerebellum’s role

By Heather Allen

Autism breakthrough: The cerebellum may be the key to a new treatment for autism

Pioneering new research on the role of the cerebellum could lead to an effective treatment for autism.

The research forms part of a study by Professor Frank Van Overwalle, from the Brain, Body, and Cognition research group at Vrije Universiteit Brussel (VUB). The study highlights the cerebellum’s crucial role in both motor coordination and social-cognitive functions, expanding its known importance beyond just movement control. According to Professor Van Overwalle, this research offers a fresh perspective on the cerebellum’s role and paves the way for new treatments for psychiatric and neurological conditions, such as autism spectrum disorders.

The results of magnetic brain stimulation tests on autistic subjects were used in the study. The subjects showed measurable improvements when performing a sequence of cognitive tasks. More complex tasks are now being tested to see if further improvements can be made, with the goal of developing practical treatments for people with autism.

The aim of the research is to highlight the underappreciated role of the cerebellum in both motor functions and social-cognitive processes. The research supports a growing trend in neuroscience, which has historically concentrated more on the cerebrum, the larger, main part of the brain.

Although small compared to the rest of the brain, the cerebellum holds more than half of the neurons in the body. Often referred to as the back brain, the cerebellum is located at the back of the head, just above and behind where the spinal cord connects to the brain, at ear-level. The cerebellum forms a half-circle shape around the brain stem, which connects the brain to the spinal cord. It is easily identifiable by the series of horizontal grooves from top to bottom. The average adult cerebellum is about 11.5cm wide, between 3-4cm tall in the middle and 5-6cm on the sides, and weighs between 136-169 grams.

Although unusual, research on the cerebellum is nothing new. Over two hundred years ago, scientists started analysing the cerebellum by studying people with cerebellum damage. Subjects often had trouble keeping their balance or would have difficulty reaching for objects. Later, evidence was found that cerebellum damage could have other effects, including difficulty in learning new words or skills.

Crucially, the posterior cerebellum has a critical role in human social and emotional learning and decision making. Three systems and related neural networks support this cerebellar function: a biological action observation system; a mentalising system for understanding a person’s mental and emotional state; and a limbic network supporting core emotional pleasure/displeasure and arousal processes. The study describes how these systems and networks support social and emotional learning via connections initiating and terminating in the posterior cerebellum and cerebral neocortex.

Professor Van Overwalle’s research tests the hypothesis that a major function of the cerebellum is to identify and encode temporal sequences of events. Researchers believe that this function might help to fine-tune and automatise social and emotional learning. The study discusses tests conducted using neuroimaging and non-invasive stimulation that provide evidence for cerebellar sequencing, as well as accounts of the cerebellum’s role in these social and emotional processes.

For decades, the cerebellum was primarily associated with motor coordination, Professor Van Overwalle explains: “People with cerebellar abnormalities often experience motor issues. For example, they struggle to smoothly touch their nose with a finger. These difficulties highlight the cerebellum’s essential role in refining motor movements.”

The research extends beyond motor functions, exploring the cerebellum’s involvement in social and cognitive abilities. Professor Van Overwalle’s findings reveal that abnormalities in the cerebellum not only lead to motor deficits but are also linked to emotional and behavioral disorders. According to Professor Van Overwalle, research on individuals with autism demonstrates how non-invasive brain stimulation techniques like magnetic stimulation can improve social task performance.

Another breakthrough highlighted in the study is the use of transcranial electrical stimulation (tES), a cheaper and more accessible technique compared to magnetic stimulation. While the effects of tES are still limited, the research group is committed to further development, seeing its potential for wide-scale application in the future.

“Our hope is to refine these techniques further to improve social and cognitive functions in people with autism,” Professor Van Overwalle says.

Source: Social and emotional learning in the cerebellum by Frank Van Overwalle, 21 October 2024, Nature Reviews Neuroscience.

Categories
Cognitive science

You don’t have to get the picture to love the story

Lack of ability to visualise does not impair a reader’s enjoyment, research finds

By Heather Allen

Picture pleasure: Being able to visualise a story is not necessary for enjoyment of reading.
(Image: Radboud University)

When most of us read, we imagine the story in our heads. Being able to picture the scene helps us to experience the reality of the story, to engage with it and to make sense of it. But what if we do not have the capacity to visualise? A new study by researchers at Radboud University has found that staying engaged with a story is more challenging for people with aphantasia, a condition which makes it difficult or impossible to imagine what is described. However, the study found that aphantasia does not otherwise impair the enjoyment of reading.

Aphantasia was first discovered in 2015, and people with the condition find it difficult or impossible to create visual images of concepts, objects or scenes, or to recall memories in a visual way. It is estimated that five per cent of the world’s population has this condition. Researchers Laura Speed, Lynn Eekhof and Marloes Mak from Radboud University sought to discover the differences in reading experience between people with aphantasia and those without the condition. A total of 47 people with aphantasia were compared to 51 controls on their experience of reading a short story and their reading habits. An established visual imagery questionnaire was used to determine whether someone had aphantasia. Participants answered questions about their experience of the story, as well as their general reading preferences and habits.

The study, recruited and conducted online, found that aphantasics were less likely to be engaged with, interested in, and absorbed in the story, and experienced reduced emotional engagement with and sympathy for the story characters, compared to controls. However, aphantasics and controls did not differ in how much they liked or appreciated the story, and the reading habits of the two groups also did not differ significantly. The results have implications for embodied theories of language, suggesting visual imagery may influence how a story is experienced, but it is not the only route to story enjoyment.

According to language scientist Laura Speed, the study’s lead author, visual imagery is thought to be involved in various cognitive processes, including short term memory, autobiographical memory and future thinking, as well as language processing. Brain imaging studies indicate that visual parts of the brain are activated during language comprehension. A growing area of research has drawn attention to people with aphantasia, raising questions about how cognition may function without imagery.

Previous studies have noted that individuals often experience disappointment when an actor does not resemble the mental image they had of a character in the film adaptation of a book they have read. Visual imagery has been associated with how transported by or absorbed in a story readers are, and subsequently how much readers enjoyed stories. Aphantasics have rated short verbal descriptions of people in distress as less emotionally moving than controls, but the same difference was not observed with photographs of people in distress.

The Radboud University study is the first to examine and compare the experience of reading a story and general reading habits between individuals with aphantasia and control participants without the condition. Participants were given the fast-fiction short story My Dead by Peter Orner to read online. The story depicts two strangers who meet and drive to a séance together, ending in a near-death experience on their way home. Their experience was assessed using three established reading experience scales: the Story Appreciation Scale, the Story World Absorption Scale, and the Transformative Reading Scale.

The Story Appreciation Scale is used to assess how much participants like and enjoy a story, and what their aesthetic experience of a story is. Story World Absorption describes the feelings people may have when reading a good story or book where they go beyond comprehending the meaning of the words on a page, to a captivating experience that helps them become completely involved in the stories they read. The Transformative Reading Scale assesses the transformative aspect of reading (how literature can change concepts of the self and others) by focusing on sympathy for story characters, resonance with the reader and their past, and experience of the story through visual and bodily experience.

“Interestingly, people with aphantasia do not report impairments in their language skills,” Dr Speed said. “It is not the case that someone who can’t visually imagine ‘red’ can’t understand the word. But visual imagery is associated with how someone experiences a story. It appears that people with aphantasia are less absorbed in the story world and feel less emotional involvement with characters.”

In addition, descriptions of scenery and actions were less appreciated by people with aphantasia than by the control group, Dr Speed said, but the groups did not differ in how much they enjoyed the story. In addition, both groups reported a similar number of books read per year, and did not differ in how frequently they read fiction or non-fiction, nor how frequently they listen to audiobooks. Both groups appear to like similar genres of fiction, with equal numbers favouring Science fiction (19), adventure (4), and crime/mystery (11).  A number of aphantasics even reported writing fiction themselves. Aphantasics reported more frequently consuming fiction and non-fiction another way, such as films or TV shows, which could reflect a preference for added visual stimulation to compensate for their reduced visual imagery.

“It seems that visual imagery is not the only way to enjoy a story,” Dr Speed said. “The plot or style of language, for example, unlike descriptions of scenery, doesn’t require strong visual imagery. Aphantasic participants in our study reported appreciating these aspects, but not descriptions of scenery. So there are, besides visual imagery, other routes to story enjoyment and language comprehension. What works for some does not necessarily work for others. It is important to explore and understand this diversity in reading approaches.”

Source: The role of visual imagery in story reading: Evidence from aphantasia, by Laura J Speed, Lynn S Eekhof and Marloes Mak, Centre for Language Studies, Radboud University, Netherlands.

https://www.sciencedirect.com/science/article/pii/S1053810024000126