Neuroscientists report in the Journal of Psychiatric Research that they have discovered a biological difference between psychopaths and non-psychopaths.
Using magnetic resonance imaging (MRI) scans, they found that a region of the forebrain known as the striatum was on average 10% larger in psychopathic individuals compared to a control group of individuals with low or no psychopathic traits.
Psychopaths, or those with psychopathic traits, are generally defined as individuals that have an egocentric and antisocial personality. It is a neuropsychiatric disorder marked by deficient emotional responses, lack of empathy, and poor behavioural controls, commonly resulting in persistent antisocial deviance and criminal behaviour. Accumulating research suggests that psychopathy follows a developmental trajectory with strong genetic influences, and which precipitates deleterious effects on widespread functional networks, particularly within paralimbic regions of the brain.
The striatum, which is a part of the forebrain, the subcortical region of the brain that contains the entire cerebrum, coordinates multiple aspects of cognition, including both motor and action planning, decision-making, motivation, reinforcement, and reward perception.
Previous studies had indicated an overly active striatum in psychopaths but had not conclusively determined the impact of its size on behaviours. The new study reveals a significant biological difference between people who have psychopathic traits and those who do not.
A better understanding of the role of biology in antisocial and criminal behaviour may help improve existing theories of behaviour, as well as inform policy and treatment.
A brain connectivity study of military veterans discovered three unique brain subtypes potentially indicating high, medium, and low susceptibility to pain and trauma symptoms.This could constitute an objective measurement of pain and trauma susceptibility, possibly leading to personalised treatments and new therapies based on neural connectivity patterns.
Comorbidity Goes Unexplored
“Chronic pain is a major public health concern, especially among veterans,” said first author Prof Irina Strigo. “Moreover, chronic pain sufferers almost never present with a single disorder but often with multiple co-morbidities, such as trauma, posttraumatic stress, and depression.”
It is already understood that both pain and trauma can affect brain connections, but this had not been studied in the context of comorbid trauma and pain. Much pain and trauma research also relies on subjective measurements, such as questionnaires, rather than objective measurements like brain scans. This study, published in Frontiers in Pain Research, addresses these problems.
Theresearchers studied a group of 57 veterans with both chronic back pain and trauma, who had quite varied symptoms in terms of pain and trauma severity. Functional MRI scans of the veterans’ brains showed the strength of connections between brain regions involved in pain and trauma. The researchers then used a statistical technique to automatically group the veterans based on their brain connection signatures, regardless of their self-reported pain and trauma levels.
Based on the veterans’ brain activity, they were sorted into three groups. Strikingly, these divisions were comparable to the severity of the veterans’ symptoms, and they fell into a low, medium, or high symptom group.
The team hypothesised that the pattern of brain connections found in the low symptom group allowed veterans to avoid some of the emotional fallout from pain and trauma, and also included natural pain reduction capabilities. Conversely, the high symptom group demonstrated brain connection patterns that may have increased their chances of anxiety and catastrophising when experiencing pain.
Interestingly, based on self-reported pain and trauma symptoms, the medium symptom group was largely similar to the low symptom group. However, the medium symptom group showed differences in their brain connectivity signature, which suggested that they were better at focusing on other things when experiencing pain, reducing its impact.
Putting the findings into future practice
“Despite the fact that the majority of subjects within each subgroup had a co-morbid diagnosis of pain and trauma, their brain connections differed,” said Prof Strigo.
“In other words, despite demographic and diagnostic similarities, we found neurobiologically distinct groups with different mechanisms for managing pain and trauma. Neurobiological-based subgroups can provide insights into how these individuals will respond to brain stimulation and psychopharmacological treatments.”
Thus far, it’s not known whether these neural hallmarks represent a vulnerability to trauma and pain or a consequence of these conditions. The technique does however provide an objective and unbiased hallmark of pain and trauma susceptibility or resilience, not reliant on subjective measures such as the surveys. In fact, subjective measurements of pain in this study would not differentiate between the low and medium groups.
Techniques using objective measures like brain connectivity appear more sensitive and could provide a clearer overall picture of someone’s resilience or susceptibility to pain and trauma, thereby guiding personalised treatment and paving the way for new treatments.
Portable MRI machines, an emerging technology that makes medical imaging accessible even in remote locations, detected ischaemic strokes in 90% of patients scanned, according to a study appearing in the journal Science Advances.
In previous studies, portable MRI devices have demonstrated they can also detect haemorrhagic as well as ischaemic strokes, helping clinicians make crucial life-saving treatment decisions quickly in remote areas for patients who lack ready access to major hospitals with expensive stationary MRI machines, the authors say.
“This is the first systematic evidence you can detect ischaemic strokes using portable, bedside devices,” noted Kevin Sheth, professor of neurology and neurosurgery at Yale School of Medicine and co-corresponding author of the study.
Outcomes for stroke patients improve dramatically the quicker they receive treatment. But access to stationary MRI machines is limited for those who live far away from major hospitals or in developing countries. And even stroke patients who have access to major hospitals often have to wait for scans with stationary MRIs because of heavy demand for the equipment. Portable scans can be used at a patient’s bedside, in ambulances, or in remote clinics, Dr Sheth said.
In addition, quickly differentiating between different types of stroke is crucial for determining proper treatment, the researchers say. Ischaemic strokes are usually treated with blood thinners. But that course of treatment is dangerous for those who experience haemorrhagic strokes or strokes in which there is bleeding in the brain.
Analysing portable MRI scans from 50 patients at Yale New Haven Hospital, the Yale and Harvard researchers found that the results largely confirmed ischaemic stroke diagnoses made by stationary MRIs. For 45 of those patients, the portable MRI detected blood clots as small as 4mm in size.
Researchers at the University of Waterloo have developed a new form of magnetic resonance imaging (MRI) that makes cancerous tissue glow in medical images. This innovation could enable more accurate detection and tracking of cancer over time.
“Our studies show this new technology has promising potential to improve cancer screening, prognosis and treatment planning,” said first author Professor Alexander Wong.
Irregular packing of cells leads to differences in the way water molecules move in cancerous tissue compared to healthy tissue. The new technology, called synthetic correlated diffusion imaging, highlights these differences by capturing, synthesising and mixing MRI signals at different gradient pulse strengths and timings.
In the largest study of its kind, the researchers collaborated with medical experts at the Lunenfeld-Tanenbaum Research Institute, several Toronto hospitals and the Ontario Institute for Cancer Research to apply the technology to a cohort of 200 patients with prostate cancer.
The synthetic correlated diffusion imaging was found to be better at delineating significant cancerous tissue than current imaging technique, making it a potentially powerful addition to the toolbox for doctors and radiologists.
“Prostate cancer is the second most common cancer in men worldwide and the most frequently diagnosed cancer among men in more developed countries,” said Prof Wong. “That’s why we targeted it first in our research.
“We also have very promising results for breast cancer screening, detection, and treatment planning. This could be a game-changer for many kinds of cancer imaging and clinical decision support.”
49-year-old female with past medical history of mitral valve disease and tricuspid valve regurgitation who developed headache followed by cough and fever presented to the ER with right upper eyelid ptosis (drooping). Credit: Radiological Society of North America and Scott H. Faro, M.D.
Approximately one in 100 patients hospitalised with COVID will likely develop complications of the central nervous system, according to a large international study. These can include stroke, haemorrhage, and other potentially fatal complications. The study was presented at the annual meeting of the Radiological Society of North America (RSNA).
“Much has been written about the overall pulmonary problems related to COVID, but we do not often talk about the other organs that can be affected,” said study lead author Scott H. Faro, MD, FASFNR, professor of radiology and neurology at Thomas Jefferson University. “Our study shows that central nervous system complications represent a significant cause of morbidity and mortality in this devastating pandemic.”
Dr Faro initiated the study after finding that only a small number of cases informed existing literature on central nervous system complications in hospitalised COVID patients.
To build a more complete picture, he and his colleagues analysed nearly 40 000 cases of hospitalised COVID patients, admitted between September 2019 and June 2020. Their average age was 66 years old, and two thirds were men.
Confusion and altered mental status were the most common causes of admission followed by fever. Comorbidities such as hypertension, cardiac disease and diabetes were common.
There were 442 acute neuroimaging findings most likely associated with the viral infection, with central nervous system complications in 1.2% of this large patient group.
“Of all the inpatients who had imaging such as MRI or a CT scan of the brain, the exam was positive approximately 10% of the time,” Dr Faro said. “The incidence of 1.2% means that a little more than one in 100 patients admitted to the hospital with COVID are going to have a brain problem of some sort.”
Ischaemic stroke, with an incidence of 6.2%, was the most common complication, followed by intracranial haemorrhage (3.72%) and encephalitis (0.47%).
A small percentage of unusual findings was uncovered, such as acute disseminating encephalomyelitis, an inflammation of the brain and spinal cord, and posterior reversible encephalopathy syndrome, a syndrome that mimics many of the symptoms of a stroke.
“It is important to know an accurate incidence of all the major central nervous system complications,” Dr Faro said. “There should probably be a low threshold to order brain imaging for patients with COVID.”
In a mouse model study of MRI-guided focused ultrasound-induced blood-brain barrier (BBB) opening at MRI field strengths ranging from approximately 0 T (outside the magnetic field) to 4.7 T, the static magnetic field dampened the detected microbubble cavitation signal and decreased the BBB opening volume. Credit: Washington University School of Medicine in St. Louis
Using a combination of ultrasound, MRI field strength and microbubbles can open the blood-brain barrier (BBB) and allow therapeutic drugs to reach the diseased brain location with MRI guidance.
Using the physical phenomenon of cavitation, it is a promising technique that has been shown safe in patients with various brain diseases, such as Alzheimer’s diseases, Parkinson’s disease, ALS, and glioblastoma. While MRI has been commonly used for treatment guidance and assessment in preclinical research and clinical studies, until now, researchers did not know the impact that MRI scanner’s magnetic field had on the BBB opening size and drug delivery efficiency.
Hong Chen, associate professor of biomedical engineering at Washington University in St. Louis, and her lab have found for the first time that the magnetic field of the MRI scanner decreased the BBB opening volume by 3.3-fold to 11.7-fold, depending on the strength of the magnetic field, in a mouse model. The findings were in Radiology.
Prof Chen conducted the study on four groups of mice. After they were injected microbubbles, three groups received focused-ultrasound sonication at different strengths of the magnetic field: 1.5 T (teslas), 3 T and 4.7 T, and one group was never exposed to the field.
The researchers found that the microbubble cavitation activity, or the growing, shrinking and collapse of the microbubbles, decreased by 2.1 decibels at 1.5 T; 2.9 decibels at 3 T; and 3 decibels at 4.7 T, compared with those that had received the dose outside of the magnetic field. Additionally, the magnetic field decreased the BBB opening volume by 3.3-fold at 1.5 T; 4.4-fold at 3 T; and 11.7-fold at 4.7 T. No tissue damage from the procedure was seen.
Following focused-ultrasound sonication, the team injected a model drug, Evans blue dye, to investigate whether the magnetic field affected drug delivery across the BBB. The images showed that the fluorescence intensity of the Evans blue was lower in mice that received the treatment in one of the three strengths of magnetic fields compared with mice treated outside the magnetic field. The Evans blue trans-BBB delivery was decreased by 1.4-fold at1.5 T, 1.6-fold at 3.0 T and 1.9-fold at 4.7 T when compared with those treated outside of the magnetic field.
“The dampening effect of the magnetic field on the microbubble is likely caused by the loss of bubble kinetic energy due to the Lorentz force acting on the moving charged lipid molecules on the microbubble shell and dipolar water molecules surrounding the microbubbles,” said Yaoheng (Mack) Yang, a doctoral student in Prof Chen’s lab and the lead author of the study.
“Findings from this study suggest that the impact of the magnetic field needs to be considered in the clinical applications of focused ultrasound in brain drug delivery,” Prof Chen said.
In addition to brain drug delivery, cavitation is also used in several other therapeutic techniques, such as histotripsy, the use of cavitation to mechanically destroy regions of tissue, and sonothrombolysis, a therapy used after acute ischaemic stroke. The magnetic field’s damping effect on cavitation is expected to affect the treatment outcomes of other cavitation-mediated techniques when MRI-guided focused-ultrasound systems are used.
Manganese, a common trace mineral, could improve MRI scans of hearts after a heart attack and guide therapy, according to a new study.
By far the most widely used contrast agent for MRI is gadolinium, which improves the visibility of different organs and tissue types in MRI scans. However, it is taken up equally by cells regardless of their activity, and spreads out in damaged tissue. Furthermore, there are also extremely rare instances of serious kidney damage from its use.
Manganese, besides being less toxic, has a useful property in that it competes with calcium uptake. Calcium handling is highly sensitive to altered heart muscle viability and changes rapidly after damage. Manganese ions enter heart muscle cells through calcium channels, and thus give a useful surrogate for heart tissue viability.
The contrast agent was tested first in vitro with heart muscle cells, and then in mice which had a myocardial infarction (heart attack) induced. The manganese contrast agent was administered with a calcium supplement or administered slowly to negate the effects of manganese interfering with the heart’s calcium channel. Findings were evaluated by examining the infarct size and blood supply at three key intervals: one hour, one day and 14 days after a myocardial infarction was induced. Overall, the manganese contrast agent was superior to gadolinium.
These findings could have major implications for heart attack treatment, if confirmed. They could also be greatly useful in preclinical evaluation of treatments for patients with cardiac ischaemia – where blood supply to the heart muscle is reduced, possibly leading to cardiac arrest.
Furthermore, if manganese-enhanced MRI is performed within the first few hours of a heart attack it could be used to determine the optimal treatment regime for individual patients – helping to regulate changes in the cardiac muscle and thereby further improving survival chances.
“Magnetic resonance imaging (MRI) is increasingly used to diagnose and give information on heart conditions,” said lead researcher Dr Patrizia Camelliti, Senior Lecturer in Cardiovascular Science, University of Surrey. “This research using mice allows us to measure the health status of the heart muscle rapidly after a heart attack and could provide important information for optimizing treatments in patients.”
Journal reference: Jasmin, N.H., et al. (2021) Myocardial Viability Imaging using Manganese‐Enhanced MRI in the First Hours after Myocardial Infarction. Advanced Science. doi.org/10.1002/advs.202003987.
A study of non-hospitalised individuals who had recovered from COVID but still experienced breathing difficulties had revealed lung damage where other tests were unable to.
To investigate post-COVID lung damage, Prof Fergus Gleeson led a study involving 10 participants aged 19 to 69, of whom eight had been experiencing breathing difficulties three months after a COVID infection. They had not been hospitalised for their COVID, and conventional scans had not been able to detect any abnormalities with their lungs.
The patients’ lungs were imaged using magnetic resonance imaging (MRI) scans with xenon present in the lungs. Xenon, a noble gas, is non-toxic Xenon has a long history of use as a contrast agent, and is soluble with pulmonary tissue, allowing for investigation of specific lung characteristics that are connected to gas exchange and alveolar oxygenation, at the level of small airways where pulmonary function tests (PFTs) cannot provide information.
The scans revealed that there was indeed lung damage preventing alveolar oxygenation – and it was unexpectedly severe.
Prof Gleeson said, “I was expecting some form of lung damage, but not to the degree that we have seen.”
The findings help to explain the phenomenon of “long COVID”, where patients who have recovered from COVID continue to experience fatigue and breathing difficulties months after the original infection has ended.Based on the findings, Prof Gleeson will undertake a study with a further 100 participants based on the same criteria.
