Tag: Neuroscience

Does smoking increase your risk for dementia and cognitive decline?

Photo by Abhishek Koli on Unsplash

Scientists from the Uniformed Services University (USU), Emory University and the University of Vermont have found that cigarette smoking is linked to increased lesions in the brain’s white matter, called white matter hyperintensities.  White matter hyperintensities, detected by MRI scan, are associated with cognitive decline and Alzheimer’s disease. These findings may help explain the link between smoking and increased rates of dementia and other forms of cognitive decline.

The study, “Associations of cigarette smoking with gray and white matter in the UK Biobank” was published online in the journal, Neuropsychopharmacology, https://rdcu.be/b1jPS

In June 2019, the Surgeons General of the Army, Navy, Air Force, and United States, released an open letter stating that tobacco use is a threat to the health and fitness of U.S. military forces and compromises readiness. This burden also extends to care provided by the Veterans Health Administration, which spends more than $2.5 billion annually on smoking-related care.  In response, Dr. Joshua Gray, assistant professor of Medical and Clinical Psychology and Neuroscience at USU, and colleagues, examined the association between cigarette smoking and brain structure. Cigarette smoking is associated with increased risk for myriad health consequences including increased risk for neuropsychiatric conditions, but research on the link between smoking and brain structure is limited.

Their study was the largest of its kind, including MRI brain scans from more than 17,000 individuals from the UK Biobank, a large cohort of volunteers from across the United Kingdom. They found that smoking was associated with smaller total gray and white matter volume, increased white matter lesions, and variation in specific gray matter regions and white matter tracts. By controlling for important variables that often co-occur with smoking, such as alcohol use, this study identified distinct associations between smoking and brain structure, highlighting potential mechanisms of risk for common neuropsychiatric consequences of smoking such as depression and dementia.

“Cigarette smoking is known to elevate risk for neuropsychiatric conditions such as depression and dementia. We found that smoking is associated with multiple aspects of brain structure, in particular with increased white matter lesions. White matter lesions are linked to many of the same neuropsychiatric diseases as smoking,” said Gray.  “Although further research is needed to understand to what extent smoking is a cause or consequence of these aspects of brain structure, our findings suggest a mechanism that links smoking to increased risk for dementia, depression, and other brain diseases.”

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Taking Antidepressants During Pregnancy Increases Risk of Autism by 87%

Ground breaking study published in JAMA Pediatrics looks at outcomes of 145,456 pregnancies after antidepressant use

Credit: Hepingting, CC BY SA 2.0, https://flic.kr/p/95h8gu

Using antidepressants during pregnancy greatly increases the risk of autism, Professor Anick Bérard of the University of Montreal and its affiliated CHU Sainte-Justine children’s hospital revealed today. Prof. Bérard, an internationally renowned expert in the fields of pharmaceutical safety during pregnancy, came to her conclusions after reviewing data covering 145,456 pregnancies. “The variety of causes of autism remain unclear, but studies have shown that both genetics and environment can play a role,” she explained. “Our study has established that taking antidepressants during the second or third trimester of pregnancy almost doubles the risk that the child will be diagnosed with autism by age 7, especially if the mother takes selective serotonin reuptake inhibitors, often known by its acronym SSRIs.” Her findings were published today in JAMA Pediatrics.

Using antidepressants during pregnancy greatly increases the risk of autism, Professor Anick Bérard of the University of Montreal and its affiliated CHU Sainte-Justine children’s hospital revealed today. Prof. Bérard, an internationally renowned expert in the fields of pharmaceutical safety during pregnancy, came to her conclusions after reviewing data covering 145,456 pregnancies. “The variety of causes of autism remain unclear, but studies have shown that both genetics and environment can play a role,” she explained. “Our study has established that taking antidepressants during the second or third trimester of pregnancy almost doubles the risk that the child will be diagnosed with autism by age 7, especially if the mother takes selective serotonin reuptake inhibitors, often known by its acronym SSRIs.” Her findings were published today in JAMA Pediatrics.

Bérard and her colleagues worked with data from the Quebec Pregnancy Cohort and studied 145,456 children between the time of their conception up to age ten. In addition to information about the mother’s use of antidepressants and the child’s eventual diagnosis of autism, the data included a wealth of details that enabled the team to tease out the specific impact of the antidepressant drugs. For example, some people are genetically predisposed to autism (i.e., a family history of it.) Maternal age, and depression are known to be associated with the development of autism, as are certain socio-economic factors such as being exposed to poverty, and the team was able to take all of these into consideration. “We defined exposure to antidepressants as the mother having had one or more prescription for antidepressants filled during the second or third trimester of the pregnancy. This period was chosen as the infant’s critical brain development occurs during this time,” Prof. Bérard said. “Amongst all the children in the study, we then identified which children had been diagnosed with a form of autism by looking at hospital records indicating diagnosed childhood autism, atypical autism, Asperger’s syndrome, or a pervasive developmental disorder. Finally, we looked for a statistical association between the two groups, and found a very significant one: an 87% increased risk.” The results remained unchanged when only considering children who had been diagnosed by specialists such as psychiatrists and neurologists.

The findings are hugely important as six to ten percent of pregnant women are currently being treated for depression with antidepressants. In the current study, 1,054 children were diagnosed with autism (0.72% of the children in the study), on average at 4.5 years of age. Moreover, the prevalence of autism amongst children has increased from 4 in 10,000 children in 1966 to 100 in 10,000 today. While that increase can be attributed to both better detection and widening criteria for diagnosis, researchers believe that environmental factors are also playing a part. “It is biologically plausible that anti-depressants are causing autism if used at the time of brain development in the womb, as serotonin is involved in numerous pre- and postnatal developmental processes, including cell division, the migration of neuros, cell differentiation and synaptogenesis – the creation of links between brain cells,” Prof. Bérard explained. “Some classes of anti-depressants work by inhibiting serotonin (SSRIs and some other antidepressant classes), which will have a negative impact on the ability of the brain to fully develop and adapt in-utero”

The World Health Organization indicates that depression will be the second leading cause of death by 2020, which leads the researchers to believe that antidepressants will likely to remain widely prescribed, including during pregnancy. “Our work contributes to a better understanding of the long-term neurodevelopmental effects of anti-depressants on children when they are used during gestation. Uncovering the outcomes of these drugs is a public health priority, given their widespread use,” Prof. Bérard said.

About this study:Takoua Boukhris, Odile Sheehy, Laurent Mottron, MD, PhD, and Anick Bérard, PhD, published “Antidepressant use during pregnancy and the risk of autism spectrum disorder in children” in JAMA Pediatrics on December 14, 2015.

Anick Bérard, PhD, is a professor at the University of Montreal’s Faculty of Pharmacy and a researcher at the CHU Sainte-Justine Research Centre.

This study was supported by the Canadian Institutes of Health Reseach (CIHR) “Quebec Training Network in Perinatal Research”, and the Fonds de la recherche du Québec – Santé (FRQ-S).,

Dr. Bérard is the recipient of a FRQ-S research Chair on Medications and Pregnancy. Dr Bérard is a consultant for plaintiffs in litigations involving antidepressants and birth defects.

The University of Montreal is officially known as Université de Montréal.

“Social” and “Visual”

Photo by jesse orrico

In Some Children with Autism, “Social” and “Visual” Neural Circuits Don’t Quite Connect

Researchers combined eye gaze data with brain scans to discover that in a common subtype of autism, in which ASD toddlers prefer images of geometric shapes over those of children playing, brain areas responsible for vision and attention are not controlled by social brain networks, and so social stimuli are ignored.

Among the first and most-documented symptoms of autism spectrum disorder (ASD) is a child’s aversion to interaction with others. Specifically, they appear uninterested in social activities and stimuli that would normally attract a young child’s attention, such as watching other children play, sing or dance.



In a new study, published online December 17, 2019 in the journal eLife, researchers at University of California San Diego School of Medicine combined a novel vision tracking program with brain imaging to find that ASD toddlers who ignore social stimuli and prefer to look at moving, colorful geometric images, had more severe social symptoms and lower levels of brain activity connecting social and visual attention brain networks.

“This indicates that in a subtype of ASD toddlers with a preference for geometric images rather than pictures of children — about 20 percent of toddlers with autism — there is a disconnection between visual and social brain networks. In these ASD toddlers, colorful moving shapes, rather than fun social-emotional stimuli, control neural activity, attention and learning,” said senior and corresponding author Karen Pierce, PhD, professor of neurosciences and co-director of the UC San Diego Autism Center of Excellence with co-author Eric Courchesne, PhD, also a professor of neurosciences.



The daily disconnection of social and visual neural networks results in attention, experience and learning to be directed towards low-level, but visually salient stimuli like colorful spinning shapes, said Pierce; this may be a causative factor in the symptoms and observed social impairment in some ASD toddlers. But the findings, she added, may also provide a new avenue for diagnosing and treating ASD in toddlers and young children.

“Currently, when a child receives a diagnosis of autism, he or she is usually referred for a fairly generic treatment based on principles of Applied Behavior Analysis. In the future, following a diagnosis, children might receive more in-depth biological evaluations that provide information about their eye gaze and brain network activation patterns, which could point to more specific treatments,” she said.

“It may also be possible that brain imaging and eye tracking could be used together to determine the efficacy of treatment if a second biological evaluation is conducted at some point following a period of treatment.”



Pierce and colleagues have been investigating the potential of eye gaze technology in diagnosing and treating ASD for several years. In 2010, for example, they reported that, in a simple one minute eye tracking test, infants as young as 14 months who preferred movies of geometric shapes more often than movies of children dancing and doing yoga were subsequently diagnosed as ASD using a longer, gold-standard behavioral diagnostic test (the “ADOS”). Conversely, typically developing infants and toddlers preferred watching the “social” images.

In this new study, the researchers combined eye tracking (in which a camera monitors and documents where and what a child is looking at on a screen) with functional magnetic resonance imaging (fMRI) data detailing interconnectivity between different brain circuits.

“Basic neuroscience has found that the human brain has many so-called ‘resting state’ networks, each involved in different sensory, attention, cognitive and social functions. These networks are active even when we are not engaged in any explicit task, even during natural sleep,” said Courchesne.  

“One social network, the Default Mode Network or DMN, is highly active when we are thinking about ourselves and others. It is thought that abnormalities in the DMN may be central to why individuals with autism have social difficulties. Since experience-dependent mechanisms, such as what someone looks at, drives brain development, understanding what someone visually attends — social or non-social stimuli — can provide invaluable information.”


Examining the combined data for both ASD toddlers and non-ASD comparison groups, the researchers found less-than-typical neural interaction (hypoconnectivity) between social brain circuitry like the DMN and visual and attention networks in ASD children. The greater the hypoconnectivity, the more severe the social-communication difficulties, particularly in toddlers with geometric-preference ASD.

Pierce said the findings add new information and detail to the still largely mysterious and complex portrait of ASD. “But by combining clinical phenotype information, such as scores on tests of social competency, with brain imaging and eye tracking as we do here, we are developing more accurate, early approaches to diagnosing ASD and identifying brain-eye tracking subtypes. We will soon begin pilot studies to develop targeted treatments for this subtype.”

Co-authors include: first author Michael V. Lombardo, Instituto Italiano di Tecnologia and University of Cambridge; Lisa Eyler, UC San Diego and Veterans Affairs San Diego Healthcare System; Adrienne Moore, Michael Datko, Cynthia Barnes and Debra Cha, all at UC San Diego.

Funding for this research came, in part, from the National Institute for Mental Health (R01-MH080134, P50-MH081755), the National Foundation for Autism Research, the National Institute on Deafness and Other Communication Disorders (R01-DC016385), Congressionally Directed Medical Research Programs (AR130409), the European Research Council and fellowships from Jesus College, Cambridge and the British Academy.

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Disclosure: An invention disclosure form was filed by Karen Pierce with University of California San Diego on March 5, 2010. The other authors report no biomedical financial interests or potential conflicts of interest.