Radically different
A cellular-resolution molecular map details how Down syndrome alters human brain development before birth. The study analyzed more than 100,000 nuclei from human prenatal neocortex samples collected across 26 pre-genotyped donors during gestational weeks 13 to 23—the only window during which all the cortical neurons a person will carry for their entire life are generated. The findings suggest that Down syndrome disrupts the developmental sequence of that process, creating shifts that may help explain later differences in cognition, learning, and sensory processing.
This work is published in Science in the paper, “A single-cell multiomic analysis identifies molecular and gene-regulatory mechanisms dysregulated in developing Down syndrome neocortex.“
“There’s a new level of detail here that had never existed before,” said Luis de la Torre-Ubieta, PhD, an assistant professor of psychiatry and biobehavioral sciences at UCLA and a member of the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research. “For the first time, we can really try to understand systematically what’s going on in the developing brain of individuals with Down syndrome.”
“No one had looked at the developing human brain in Down syndrome directly using single-cell genomics,” he continued.
The Down syndrome research field has historically focused on two areas: the adult brain and the disorder’s connection to neurodegeneration. What remained largely unexamined, despite clear indicators that Down syndrome is a developmental condition, was how the condition shapes the developing brain itself.
The development of the prenatal neocortex typically follows a tightly orchestrated sequence. Progenitor cells must first divide repeatedly to expand their own pool, building up a sufficient base for all future neurons. Only then do they begin differentiating into neurons, starting with deep-layer cell types and progressing toward upper-layer cells in a carefully timed order.
The study found that progenitor cells appear to rush prematurely into neuron production, depleting their own pool and skewing the balance of neuron types generated. Specifically, the researchers observed a relative increase in upper-layer intratelencephalic neurons and a reduction in deep-layer corticothalamic neurons.
Those two cell populations play fundamentally different roles: CT neurons project outward from the cortex—connecting to brain structures and to the spinal cord to govern sensation and movement; IT neurons wire within the cortex, connecting the two hemispheres and contributing to information processing. This finding offers a new hypothesis for how early developmental changes might contribute to the cognitive profile of the condition.
The finding also offers a new answer to a longstanding question in the field: Why do people with Down syndrome tend to have smaller brains? Earlier theories centered on elevated rates of cell death. The current study found less evidence of widespread neuronal death and instead points to the depletion of the progenitor pool.
The study employed paired single-nucleus multiomics to reconstruct not just a snapshot of which cells are present, but the regulatory programs that guide cell fate—and how those programs are disrupted in Down syndrome. Systems-level approaches also led them to uncover alterations in cell metabolism and changes in how the vasculature interacts with the developing nervous system, both of which could speed up neuron production.
The study’s significance extends beyond Down syndrome. The researchers specifically tested for overlap between the molecular disruptions they identified and the genetic risk signatures associated with other neurodevelopmental and neuropsychiatric conditions, including autism, epilepsy, and developmental delay. They found substantial convergence, particularly in the gene-regulatory networks governing the specification of IT versus CT neurons.
“Down syndrome could be a model to understand intellectual disability and neuropsychiatric disorders more broadly,” de la Torre-Ubieta said. “Also to uncover the shared biology underlying these conditions—because the mechanisms are often still unknown.”
The publication coincides with a companion paper from researchers at the University of Wisconsin-Madison, appearing in the same issue of Science. While the UCLA study focuses on the prenatal period, the Wisconsin team examined the postnatal brain, studying Down syndrome between approximately one and five years of age.
Together, the two papers provide a continuous molecular view of Down syndrome brain development from mid-gestation through infancy—a resource that did not previously exist and that the researchers expect will serve as a reference for their field for years to come.
While the researchers are careful to emphasize that the findings do not point to a near-term clinical application, the study provides the clearest picture yet of the cellular and molecular events that distinguish the Down syndrome brain during development, and a framework for identifying future therapeutic targets.
The post Single-Cell Atlas of the Prenatal Brain Reveals How Down Syndrome Reshapes Development appeared first on GEN – Genetic Engineering and Biotechnology News.
A common misconception about tantrums and meltdowns is that they’re interchangeable. But while they share some similarities in their initial expression — crying, screaming, door slamming, harsh words — they’re actually quite different. Dealing with a meltdown requires a more specialized approach, especially with kids on the autism spectrum.
The two events happen for different reasons. A child throws a tantrum when they’re angry or frustrated, acting out because they feel an injustice has been done to them. They are aware of what they’re doing and still have some sense of control. And if a child’s tantrum is ignored by their parent or caregiver, it will likely subside quickly.
Meltdowns, on the other hand, happen involuntarily and seemingly out of nowhere. They also tend to become much more intense than a typical tantrum and may involve violent behavior such as head banging, hitting others, and damaging property. Once a meltdown has started, intervention is needed to stop it, whether it’s self-imposed (e.g., removing oneself from the trigger) or external (e.g., support from the parent or caregiver). The event can last between a few minutes and several hours.
Tantrums are common among all children, but kids with autism are more likely to experience meltdowns of varying degrees, says Conner Black, PhD, associate director of the Autism Center at the Child Mind Institute.
For a child with autism, a meltdown is triggered when they become overwhelmed, whether it’s by stress, powerful emotions, sensory input, change, or something else. Their sympathetic nervous system — the network in the body responsible for our “fight-or-flight” response — goes into overdrive and they lose control.
There are several stages to an autistic meltdown and understanding them can help you know how to respond effectively. The duration and intensity of the meltdown depend on whether intervention, including learned coping skills, can stop the child from reaching a crisis point, Dr. Black explains. “Certain skills may not work every time, and that’s really no one’s fault,” he says, but once a child reaches that crisis stage, intervention is no longer useful. He describes the course of a meltdown via the phases of the behavior escalation cycle:
Once a child has started to experience a meltdown, it’s hard to get them back to baseline. Depending on the phase, certain interventions may help while others might make things worse.
First, you want to avoid triggers, Dr. Black advises. “Autistic individuals can have a lot of difficulty talking about or even understanding what their emotions are. So, it’s typically up to the parents or caregivers to identify what things can trigger them in a certain way,” he says.
For instance, some kids with autism really thrive with routine and can become agitated when there are unexpected changes. Having a visual schedule of exactly what’s going to happen during the day can help prevent that, says Dr. Black. “If you know there’s going to be a change, you can pick a time, maybe a couple of days in advance, where you talk to them about what that difference is going to be.”
And if your child is known to have meltdowns in public spaces, says Dr. Black, think about what those outside triggers are and how to prepare ahead of time. If they tend to get upset by loud noises, for example, a pair of headphones can be an item — along with phone, wallet, keys! — that you never leave the house without. If possible, work with a mental health professional to identify triggers and develop an escalation plan.
If your child has reached the agitation phase, says Dr. Black, you can try to intervene with coping skills that you’ve learned in therapy, whether it’s something as simple as removing a trigger or giving them a preferred activity in that moment to help prevent their behaviors from escalating.
Sometimes kids encounter an environment, like school, that is beyond your control but contains a wide range of potential triggers and pushes them into the agitation phase. Because their house is a more comfortable environment, kids with autism may keep themselves together at school and then quickly melt down once they get home.
“In that case, for that first hour, let them have their alone time where they can just chill,” Dr. Black suggests. “It could be eating snacks, watching a TV show, or even just sitting quietly in their room. Maybe it’s engaging in some sort of self-stimming behavior.” This can give them the space to cool down and take some time away from any sort of outside stimuli that could push them to move from the agitation phase into the escalation point of a meltdown.
It can be hard to anticipate every possible trigger, especially when there might be multiple at once on any given day. And sometimes coping strategies aren’t enough to keep a child from escalating or the trigger is too strong. Still, there are some things that Dr. Black suggests you can do to try to keep them from reaching that crisis point.
Too much talking can be overwhelming for the child at this stage and might push them to crisis, Dr. Black explains, so the less communication the better. “A simple instruction looks like using just a short sentence. Say there’s a loud noise, for example. You can just say, ‘Go get your headphones,’” he says.
Instead of trying to communicate verbally, you can hold up a visual prompt. “If your child has already been working with a therapist or if they’ve learned some coping skills, it would be helpful to have a laminated sheet readily available with their name and pictures of four different coping skill options — like headphones, deep breathing, coloring, sitting alone in their room.”
Dr. Black advises only giving a few options, as it’s already difficult for the child to focus while they’re upset. Additionally, if they don’t choose one right away and you want to try again, he recommends that you “let there be silence for 60 seconds at minimum between prompts, because you don’t want to over-prompt and exacerbate the situation even more.” But providing these choices allows them to maintain their autonomy, which is important during escalation.
“Once they get to that apex, they’ve reached the point of no return and just need to go through the process,” says Dr. Black. He stresses that at this point, communication needs to be very minimal or nonexistent.
“The goal switches to really being able to maintain safety for both the individual as well as the family members in the area,” Dr. Black explains. “If they’re harming themselves, such as head banging, move them to their bed so at least it’s on something that’s softer and not going to potentially cause significant injury.”
Efforts to make sure the child is as safe as possible can put you in harm’s way. “If there’s aggression, you can be watching and making sure they’re safe but not getting too close where you could get aggressed upon,” says Dr. Black.
If there are other children in the house, Dr. Black advises that you make plans for how to keep them safe. “Maybe they can go to their room and lock the door while it’s happening,” he says. “Some families have the other kids go to the car and sit and wait until their parents come out to get them.”
If the crisis phase goes on for a long period of time, says Dr. Black, “this is when you’d have to think about calling 911. And as kids become adolescents, the response is going to look a lot different. Because of size alone, it’s a little bit easier to manage the situation in a 5-year-old than it would be in a 15-year-old.”
Dr. Black advises that you get in touch with your local police department or EMT service in advance to let them know you have a child with autism in the home, so if you call during an emergency, they are already familiar with your family.
Watch for signs that the child is beginning to de-escalate, Dr. Black says. “All you’re doing at this point is maintaining safety until you’re really able to see a lessening of the intensity of the behavior or the frequency decreases a little bit.” Then, he says, you can start to slowly communicate with them again. You really need to be careful here, because it may look like they’re calming down, but if they’re pushed too hard and they’re not ready to talk, they might go right back into crisis phase.
At the recovery phase, “the whole family is recovering,” Dr. Black says. It’s at this point where you can all debrief and work through what may have triggered this escalation and how to possibly prevent it in the future.
“Make sure you’re also debriefing separately with the other siblings in the home after it happens,” Dr. Black adds. “They’ve just witnessed something that may have been traumatic and really stressful for them. There’s often so much focus given to the child with the big behaviors in the moment.”
Sometimes, a child or teen may suffer from frequent meltdowns to the point that it’s interfering with their quality of life and their ability to attend school. At that time, a mental health professional may recommend working with a psychiatrist to add medication to their treatment.
The type of medication depends on the underlying mechanisms contributing to the behaviors, Dr. Black says. “For instance, if it’s coming from significant anxiety, psychiatrists may prescribe an SSRI like Prozac or Zoloft. If a child has co-occurring ADHD, which is very common, stimulant or non-stimulant ADHD medication might be recommended. And if the behavior stems from irritability or some kind of rigidity, antipsychotic medications like Abilify or risperidone can be useful.”
Dr. Black notes that when kids receive the support they need, their quality of life really improves. “I’ve seen that when families work with therapists to come up with different behavioral plans and figure out a proper medication regimen, there’s a lot of improvement in behavior challenges,” he says. “The duration, frequency, and intensity of the meltdowns decrease as the child learns how to handle strong emotions and parents learn how to respond to them. And the medication can help to increase their likelihood of being able to use coping skills or regulation techniques to calm back down when they start to get really frustrated.”
The post How to De-Escalate an Autistic Meltdown appeared first on Child Mind Institute.