4 ms·

The two processes are not entirely analogous. They are both the result of the body reacting to external stress, and to become more fit for the environment that

The two processes are not entirely analogous. They are both the result of the body reacting to external stress, and to become more fit for the environment that creates the stress. In the weightlifting example this is a positive change — the body gets stronger, as long as the exercise program is good. In the TBI and trauma cases, though, the external stresses are negative, not positive, thus the adaptations are negative as well. Teach a young brain that the world is stressful and scary and the brain will remember this, and act that way even when removed to a less scary world.

blindriver 3y ago
The brain "remembering" has zero link with gene expression, which is what the entire article is about. In fact nothing you mention above responds to the question of gene expression. There's no evidence whatsoever that the change in behavior of an individual after stress is linked to differences in gene expression.
- InSteady 3y ago
  That's quite the sweeping claim. Some quick googling suggests otherwise. "Chronic stress induces significant gene expression changes in the prefrontal cortex alongside alterations in adult hippocampal neurogenesis" >In this study, unpredictable chronic mild stress in mice resulted in a deficit in neuronal dendritic tree development and neuroblast migration in the hippocampal neurogenic niche. To investigate molecular pathways underlying neurogenesis alteration, genome-wide gene expression changes were assessed in the prefrontal cortex, hippocampus and the hypothalamus alongside neurogenesis changes. Cluster analysis showed that the transcriptomic signature of chronic stress is much more prominent in the prefrontal cortex compared to the hippocampus and the hypothalamus. Pathway analyses suggested huntingtin, leptin, myelin regulatory factor, methyl-CpG binding protein and brain-derived neurotrophic factor as the top predicted upstream regulators of transcriptomic changes in the prefrontal cortex. Involvement of the satiety regulating pathways (leptin) was corroborated by behavioural data showing increased food reward motivation in stressed mice. Behavioural and gene expression data also suggested circadian rhythm disruption and activation of circadian clock genes such as Period 2. [1] https://academic.oup.com/braincomms/article/2/2/fcaa153/5912014 https://academic.oup.com/braincomms/article/2/2/fcaa153/5912...
  - blindriver 3y ago
    You didn't read the paper, and you didn't understand it. It didn't make a link between gene expression and behavioral changes. It just noted a change in gene expression in a handful of mice, basically the same study as the above.
    - InSteady 3y ago
      >Many target genes, upstream regulators and signalling pathways involved in the PFC response in our study could be linked to dendritic remodelling and spine atrophy, a well-described effect of chronic stress on the PFC. Based on the IPA pathway and upstream regulator analysis, glutamatergic and calcium signalling, as well as Htt and Bdnf-centred networks stood out as the most significantly involved. Indeed, repeated stress is known to cause suppressed glutamate receptor expression and signalling in the PFC, which is thought to be linked to dendritic atrophy (Yuen et al., 2012). Many recent studies have explored the antidepressant potential of ketamine in chronic stress animal models of depression, strengthening the glutamatergic theory of depression (Zhu et al., 2015; Sun, 2016). In addition, disruption of glutamatergic signalling has been previously linked to hyperactivity (Procaccini et al., 2011). The animals in the study, as expected, showed depression-associated and hyperactivity behaviors. This study wasn't looking at any specific thing in a fine-grained sense, let alone trying to establish causation. But "no link" seems like quite a stretch.
      - blindriver 3y ago
        Yes, of course they showed effects from the UCMS. But not one single sentence in that report said that those effects were from gene expression. YOU are the only one adding a link there. It's easy for someone like you to just say there's a link, but not even the study pretends to say there's a link between the results of trauma are because of gene expression.
lazide 3y ago
The world is often stressful and scary.
- SamoyedFurFluff 3y ago
  I think you’re either someone who has suffered abuse and haven’t yet unlearned the effects of it, or you haven’t suffered abuse from a child and doesn’t have firsthand experience on how much it damages you. Is the world often stressful and scary? Yes. But the lessons that trauma teaches a child do not help the adult manage fear nor stress. For example: a child who has to care for their alcoholic parent can risk growing into an adult that doesn’t know when they’re being taken advantage because they were literally taken advantage of since childhood. A child who was severely beaten at the slightest infraction risks growing up into an adult that cannot handle even minor conflict because they associate being disagreed with to broken bones.
  - lazide 3y ago
    Oh I’m well aware. Some have those results. Some have the opposite results and lean into learning how to handle those situations. That is also a very common reaction. Firefighters, EMTs, Nurses, Paramedics, LEO, smoke jumpers, and many Soldiers of all stripes have the same backgrounds. 80%+ in my experience. A surprising (perhaps) numbers of skydivers and climbers too. Including the West Point graduates, special forces (officers and enlisted), SWAT members, ICU and ED nurses, etc. that I’ve known personally. And several CEOs of tech companies. One that I know who I personally saw beaten (as a child) at the slightest infraction or none at all until I stepped in (as a child myself) to stop it, became a decorated officer in USSOCOM and did multiple combat tours in Afghanistan. And at least two (now) Majors and a Colonel I’ve known since they were kids. The world is not as simple as it appears. Most folks who end up in uncommon places did so because they experienced uncommon things and learned lessons from it that most people never will have the chance to learn. Folks who haven’t learned those lessons tend to not survive many of those places for long.
    - giraffe_lady 3y ago
      > Some have those results. Some have the opposite results and lean into learning how to handle those situations. That is also a very common reaction. Childhood trauma is a routine area of clinical specialization because it is so common, and I've never known anyone in that field to hold this position. Anecdotally sure yes plenty of traumatized children become successful adults but very simply and grimly most do not. Extreme survivorship bias at play here, often literally. And separately I am not sure, in this context, considering what we now know about the behavior of american soldiers in afghanistan, that people being drawn to that environment or succeeding within it is evidence of anything positive about them.

blindriver 3y ago

The brain "remembering" has zero link with gene expression, which is what the entire article is about. In fact nothing you mention above responds to the question of gene expression. There's no evidence whatsoever that the change in behavior of an individual after stress is linked to differences in gene expression.

InSteady 3y ago
That's quite the sweeping claim. Some quick googling suggests otherwise. "Chronic stress induces significant gene expression changes in the prefrontal cortex alongside alterations in adult hippocampal neurogenesis" >In this study, unpredictable chronic mild stress in mice resulted in a deficit in neuronal dendritic tree development and neuroblast migration in the hippocampal neurogenic niche. To investigate molecular pathways underlying neurogenesis alteration, genome-wide gene expression changes were assessed in the prefrontal cortex, hippocampus and the hypothalamus alongside neurogenesis changes. Cluster analysis showed that the transcriptomic signature of chronic stress is much more prominent in the prefrontal cortex compared to the hippocampus and the hypothalamus. Pathway analyses suggested huntingtin, leptin, myelin regulatory factor, methyl-CpG binding protein and brain-derived neurotrophic factor as the top predicted upstream regulators of transcriptomic changes in the prefrontal cortex. Involvement of the satiety regulating pathways (leptin) was corroborated by behavioural data showing increased food reward motivation in stressed mice. Behavioural and gene expression data also suggested circadian rhythm disruption and activation of circadian clock genes such as Period 2. [1] https://academic.oup.com/braincomms/article/2/2/fcaa153/5912014 https://academic.oup.com/braincomms/article/2/2/fcaa153/5912...
- blindriver 3y ago
  You didn't read the paper, and you didn't understand it. It didn't make a link between gene expression and behavioral changes. It just noted a change in gene expression in a handful of mice, basically the same study as the above.
  - InSteady 3y ago
    >Many target genes, upstream regulators and signalling pathways involved in the PFC response in our study could be linked to dendritic remodelling and spine atrophy, a well-described effect of chronic stress on the PFC. Based on the IPA pathway and upstream regulator analysis, glutamatergic and calcium signalling, as well as Htt and Bdnf-centred networks stood out as the most significantly involved. Indeed, repeated stress is known to cause suppressed glutamate receptor expression and signalling in the PFC, which is thought to be linked to dendritic atrophy (Yuen et al., 2012). Many recent studies have explored the antidepressant potential of ketamine in chronic stress animal models of depression, strengthening the glutamatergic theory of depression (Zhu et al., 2015; Sun, 2016). In addition, disruption of glutamatergic signalling has been previously linked to hyperactivity (Procaccini et al., 2011). The animals in the study, as expected, showed depression-associated and hyperactivity behaviors. This study wasn't looking at any specific thing in a fine-grained sense, let alone trying to establish causation. But "no link" seems like quite a stretch.
    - blindriver 3y ago
      Yes, of course they showed effects from the UCMS. But not one single sentence in that report said that those effects were from gene expression. YOU are the only one adding a link there. It's easy for someone like you to just say there's a link, but not even the study pretends to say there's a link between the results of trauma are because of gene expression.

lazide 3y ago

The world is often stressful and scary.

SamoyedFurFluff 3y ago
I think you’re either someone who has suffered abuse and haven’t yet unlearned the effects of it, or you haven’t suffered abuse from a child and doesn’t have firsthand experience on how much it damages you. Is the world often stressful and scary? Yes. But the lessons that trauma teaches a child do not help the adult manage fear nor stress. For example: a child who has to care for their alcoholic parent can risk growing into an adult that doesn’t know when they’re being taken advantage because they were literally taken advantage of since childhood. A child who was severely beaten at the slightest infraction risks growing up into an adult that cannot handle even minor conflict because they associate being disagreed with to broken bones.
- lazide 3y ago
  Oh I’m well aware. Some have those results. Some have the opposite results and lean into learning how to handle those situations. That is also a very common reaction. Firefighters, EMTs, Nurses, Paramedics, LEO, smoke jumpers, and many Soldiers of all stripes have the same backgrounds. 80%+ in my experience. A surprising (perhaps) numbers of skydivers and climbers too. Including the West Point graduates, special forces (officers and enlisted), SWAT members, ICU and ED nurses, etc. that I’ve known personally. And several CEOs of tech companies. One that I know who I personally saw beaten (as a child) at the slightest infraction or none at all until I stepped in (as a child myself) to stop it, became a decorated officer in USSOCOM and did multiple combat tours in Afghanistan. And at least two (now) Majors and a Colonel I’ve known since they were kids. The world is not as simple as it appears. Most folks who end up in uncommon places did so because they experienced uncommon things and learned lessons from it that most people never will have the chance to learn. Folks who haven’t learned those lessons tend to not survive many of those places for long.
  - giraffe_lady 3y ago
    > Some have those results. Some have the opposite results and lean into learning how to handle those situations. That is also a very common reaction. Childhood trauma is a routine area of clinical specialization because it is so common, and I've never known anyone in that field to hold this position. Anecdotally sure yes plenty of traumatized children become successful adults but very simply and grimly most do not. Extreme survivorship bias at play here, often literally. And separately I am not sure, in this context, considering what we now know about the behavior of american soldiers in afghanistan, that people being drawn to that environment or succeeding within it is evidence of anything positive about them.