How painful long-lasting memories are stored and why they are so strong

gettingwell4 2-3 stars Required further work, Amygdala, Cortisol, Limbic system, Memory, Neurochemicals, Stress , ,

This 2014 rodent study provided evidence for a portion of the neurophysiology that underlies how painful long-lasting memories are stored and why they are so strong. The amygdala was the brain area studied.

The researchers were misguided in news coverage by focusing on solutions such as external mechanisms to forget these memories. The researchers should think in terms of how their research can help people who can help themselves instead of having something externally done to them.

After all, we’re humans who can participate in therapy, not lab rats who need to be fixed.

http://www.pnas.org/content/111/51/E5584.full “Hebbian and neuromodulatory mechanisms interact to trigger associative memory formation”

Problematic research on the hippocampus part of the limbic system

gettingwell4 0-1 star Wasted resources, Hippocampus, Limbic system, Memory

This 2014 UK human study of the CA3 region of the hippocampus found:

“Individual differences in subjective mnemonic experience can be accurately predicted from measurable differences in the anatomy and neural coding of hippocampal region CA3.”

I emailed the authors as follows:

“I read the “CA3 size predicts the precision of memory recall” study, and I wondered how it could be used to help people.

I am not a scientist; I am a software developer by trade. I read the abstracts of each new issue of PNAS with an eye to how studies can help people, which I think is an implied reason to publicly fund research.

The study’s supporting information reveals that the participants scored no emotional involvement with the tasks’ memories. This variable thus did not influence the finding that the contexts of participants’ memories were not a factor.

Could it be that the study’s findings apply to only non-emotional memories, and that context could be a factor in memories that involve emotions?

Given the large role of the hippocampus in our emotional memories, would it not have been realistic to include emotional content in the study? Was it a design decision to not involve the participants’ emotions?

The study found that memory retrieval confusion increased with a participant’s smaller CA3 size. We know from studies such as http://www.pnas.org/content/109/9/E563.full “Childhood maltreatment is associated with reduced volume in the hippocampal subfields CA3, dentate gyrus, and subiculum” and its references that emotional experiences influence CA3 anatomy.

Could it be that the study’s participants were not all sampled from the same brain population?”

http://www.pnas.org/content/111/29/10720.full “CA3 size predicts the precision of memory recall”

Early emotional experiences change our brains: Childhood maltreatment is associated with reduced volume in the hippocampus

gettingwell4 4-5 stars Advanced knowledge, Brain development, Hippocampus, Limbic system, Stress ,

This 2011 human study by the grandfather of hippocampus stress studies, Martin Teicher, quantified childhood maltreatment using the Adverse Childhood Experiences study and Childhood Trauma Questionnaire scores:

“The strongest associations between maltreatment and volume were observed in the left CA2-CA3 and CA4-DG [dentate gyrus] subfields, and were not mediated by histories of major depression or posttraumatic stress disorder.

These findings support the hypothesis that exposure to early stress in humans, as in other animals, affects hippocampal subfield development.”

The evidence is clear that early emotional experiences change our brains. There are seldom valid reasons for researchers to exclude emotional content when designing human brain studies, especially studies that involve the hippocampus.

http://www.pnas.org/content/109/9/E563.full “Childhood maltreatment is associated with reduced volume in the hippocampal subfields CA3, dentate gyrus, and subiculum”

Let’s not miss a big clue! Embryonic precursor transplants in adult hippocampus

gettingwell4 0-1 star Wasted resources, Brain development, Hippocampus, Limbic system ,

This 2014 rodent study induced “multiple psychosis-relevant phenotypes“ by disrupting specific functions of the hippocampus. The researchers then “cured” the brain disorders:

“Transplanting interneuron progenitors derived from the embryonic medial ganglionic eminence into adult hippocampus mitigates these abnormalities.”

However, full function of the hippocampus wasn’t restored.

I disagree that this study’s findings:

“Support a rationale for targeting limbic cortical interneuron function in the prevention and treatment of schizophrenia.”

People with schizophrenia aren’t lab rats and shouldn’t be treated as such. They often don’t need something externally done to them to recover from brain disorders.

Doesn’t the fact that embryonic precursors to the adult brain helped “cure” the abnormalities tell us where to look for the disorders’ beginnings? Let’s not miss a big clue as to when brain disorders may start.

http://www.pnas.org/content/111/20/7450.full “Interneuron precursor transplants in adult hippocampus reverse psychosis-relevant features in a mouse model of hippocampal disinhibition”

Problematic research: Hippocampal memory reactivation during rest supports upcoming learning of related content

gettingwell4 0-1 star Wasted resources, Cerebrum, Hippocampus, Limbic system, Memory

This 2014 human study involved the subjects replaying hippocampal memories in the limbic system while in a restful state.

The researchers found that intentional replaying made memories stronger, and improved understanding of future related material.

However, the researchers excluded emotional memories from this study. See the human Emotional memories and out-of-body–induced hippocampal amnesia study as an example of why emotional memories are necessary in order to properly study the hippocampus. Also see Problematic research on memory for why excluding emotional memories yields questionable findings.

http://www.pnas.org/content/111/44/15845.full “Memory reactivation during rest supports upcoming learning of related content”

Hippocampus replays memories and preplays to extend memories into future scenarios

gettingwell4 4-5 stars Advanced knowledge, Hippocampus, Limbic system, Memory

This 2013 MIT rodent study of the hippocampus portion of the limbic system focused on the “place” cells in the CA1 segment of the hippocampus.

During rest and sleep, the subjects’ hippocampi replayed and consolidated memories. They also preplayed events in the place cells to imagine future scenarios of “novel spatial experiences of similar distinctiveness and complexity.”

Hippocampal preplaying was advantageous when venturing into new locations because:

“The selection of specific sequences from a larger preconfigured repertoire confers the hippocampal network with the capacity to rapidly encode multiple parallel novel experiences.”

http://www.pnas.org/content/110/22/9100.full “Distinct preplay of multiple novel spatial experiences in the rat”

Emotional memories and out-of-body–induced hippocampal amnesia

gettingwell4 5+ stars Premium, Hippocampus, Limbic system, Memory, Stress

I was happy to see that the researchers in this 2014 Swedish human study included emotional memories when studying the hippocampus. They demonstrated that including emotional memories wasn’t that difficult to do.

In fact, this study’s researchers deemed emotional memories to be necessary in order to properly study the hippocampus, as evidenced by this statement about the experiment’s scripts:

“The selected life events had a moderate emotional level to ensure episodic long-term memory encoding.”

It made me wonder whether there are scientific bases for why other researchers go to such lengths to avoid including emotions in human memory studies.

Also:

“The experiments revealed two important findings. First, the behavioral results showed that episodic encoding of life events requires perceiving the world from the first-person perspective centered on one’s real body, and violations of this basic condition produced impaired episodic recall, indicative of fragmented encoding.

Second, the brain imaging data demonstrated that encoding events experienced out-of body specifically impacts the activation of the left posterior hippocampus during retrieval, suggesting an impaired hippocampal binding mechanism during encoding.

These findings are fundamentally important, as they suggest a link between the ongoing perceptual experiences of the body and the world from the first-person perspective and the hippocampal episodic memory system.”

To conclude:

“Given the apparent requirement of a natural first-person perspective between the body and the world for intact hippocampal memory function, a dissociative out-of-body experience during an acutely stressful event could, by itself, impair the encoding mechanism and produce fragmented, spatiotemporally disorganized memories.”

http://www.pnas.org/content/111/12/4421.full “Out-of-body–induced hippocampal amnesia”

Similarity in form and function of the hippocampus in rodents, monkeys, and humans

gettingwell4 2-3 stars Required further work, Brain development, Hippocampus, Limbic system, Stress , ,

This 2013 study had something for the anti-evolutionists to chew on.

Is it anti-evolutionary for human brain and behavior researchers to not be informed by animal studies such as those that show prenatal hippocampal damage done to the fetus by the mother’s environment?

http://www.pnas.org/content/110/Supplement_2/10365.full “Similarity in form and function of the hippocampus in rodents, monkeys, and humans”

Are 50 Shades of Grey behaviors learned in infancy?

gettingwell4 5+ stars Premium, Amygdala, Brain development, Cerebrum, Cortisol, Epigenetics, Hypothalamus, Limbic system, Lower brain, Memory, Neurochemicals, Primal Therapy, Serotonin, Stress , , , , , ,

Ever wonder how someone could become attached to their early childhood abuser?

Ever wonder what underlying neurobiological conditions may account for the popularity of Fifty Shades of Grey?

This 2014 rodent study “Enduring good memories of infant trauma” linked below showed how trauma changed infants’ limbic system and lower brains. As adults, they derived a neurochemical benefit from re-experiencing the traumatic conditions:

“Trauma and pain experienced in infancy clearly led to higher rates of adult rat depression-like behavior..(but) the infant brain has limited ability to link trauma to fear areas in the brain, such as the amygdala.

These results are surprising because cues associated with trauma experienced as adults provoke fear and do not rescue depressive behavior.

It is possible that giving SSRI medications to children could be detrimental to mental health in adulthood,” Dr. Sullivan says. “We believe that our research offers the first evidence for the impact of serotonin pathways.

The infant trauma increases serotonin to produce brain programming of later life depression, and the infant trauma cue increases serotonin to alleviate the adult depressive like symptoms.”

As the study may apply to humans, let’s say that as an infant, someone was traumatized by a caregiver who, for example, bound them too tightly and left them alone for too long. What adult behaviors and other symptoms may develop as results? The person may:

  • Show depression-like symptoms that would strangely be alleviated by being bound tightly and left alone for an extended period.
  • Develop attachments to people who treated them poorly in a way that triggered them to re-experience their early childhood traumas.
  • Feel their mood lift when their infancy traumas were cued.
  • Be unable to explain and integrate with their cerebrum what was going on with their limbic system and lower brains.
  • Be caught in a circle of acting out their feelings and impulses, with unfulfilling results.

Isn’t it curious that this acting-out behavior – driven by unconscious memories of traumatic conditions – is a subject for popular entertainment? It may have resonated with personal experiences of the people who read the books and watched the movie.

What about people who want to be relieved of their symptomatic behavior? Is it a justifiable practice:

  • To pass affected people over to talk therapies that aren’t interested in directly treating the cause – a neurobiological condition that exists in the limbic system and lower brains – only the symptoms?
  • To drug affected people with the neurochemicals that their condition makes scarce – the symptoms – instead of addressing the source?

A principle of Dr. Arthur Janov’s Primal Therapy is that people are capable of treating their own originating neurobiological conditions. One of the therapeutic results is that the patient is relieved of being caught in endless circles of acting-out behavior.

That way we can have our own lives, and not be driven by what happened during early stages of our lives.

http://www.pnas.org/content/112/3/881.full “Enduring good memories of infant trauma: Rescue of adult neurobehavioral deficits via amygdala serotonin and corticosterone interaction”

Problematic research on memory

gettingwell4 < 0 Detracted from science, Cerebrum, Hippocampus, Limbic system, Memory

This 2013 Harvard human study investigated brain areas that stabilized and updated memories when reactivated:

“The timing of neural recruitment and the way in which memories were reactivated contributed to differences in whether memory reactivation led to distortions or not.

Stronger reliving improved memory.”

However, like researchers often do, they stripped all emotional memory content out of the study, presumably because messy feelings would confound their conclusions. The study used non-emotional pictures only.

The researchers wanted to apply this study to eyewitness accounts. What are the chances that an eyewitness to a murder or a violent accident or crime would have a non-emotional memory of the event?

The study’s exclusion of emotional memories called into doubt that the finding “stronger reliving improved memory” also applied to reliving emotional memories. The categorical statements the researchers claimed about memory, in particular about the hippocampus – the center of emotional memories – weren’t shown to be applicable to emotional memories.

Also, the researchers didn’t include areas of the limbic system, other than the hippocampus, that would likely participate in the reliving of emotional memories. The Making lasting memories: Remembering the significant summary study cited many studies that provided evidence of other brain areas’ involvement.

The researchers had too narrow a basis for a finding that applied across the spectrum of what can be termed memory.

http://www.pnas.org/content/110/49/19671.full “Neural mechanisms of reactivation-induced updating that enhance and distort memory”

Making lasting memories: Remembering the significant

gettingwell4 4-5 stars Advanced knowledge, Amygdala, Cerebrum, Hippocampus, Limbic system, Memory, Stress

This 2013 article summarized 158 studies related to the roles of regions in the limbic system and memory:

“Episodic memory is the capacity to recall specific experiences and to re-experience individual events.

The findings of both animal and human studies provide compelling evidence that stress-induced activation of the amygdala and its interactions with other brain regions involved in processing memory play a critical role in ensuring that emotionally significant experiences are well-remembered.”

http://www.pnas.org/content/110/Supplement_2/10402.full “Making lasting memories: Remembering the significant”

Our memories have contexts with specific places and times

gettingwell4 5+ stars Premium, Hippocampus, Limbic system, Memory

This 2014 rodent study was of the place aspect of a memory’s context. The researchers found that the CA3 segment of the hippocampus stored a unique representation of the location where the memory was formed:

“Place cells are hippocampal cells (in CA3) that fire specifically when the animal is at a certain location.

Form unique representations for every single environment.

When the animal was introduced to one of the rooms a second time the spatial map from the first exposure was reactivated.”

Our memories are formed within a specific context tied in the time aspect of a memory’s context:

“Hippocampal neurons not only track time, but do so only when specific contextual information (e.g., object identity/location) is cued.”

Our memories have contexts with specific places and times. Accessing a memory’s specific context would be a necessary part of accessing a full memory.

http://www.pnas.org/content/111/52/18428.full “Place cells in the hippocampus: Eleven maps for eleven rooms”

Our memories are formed within a specific context

gettingwell4 4-5 stars Advanced knowledge, Hippocampus, Limbic system, Memory

This 2014 primate study provided evidence that our memories are formed within a specific context:

“The hippocampus, a structure known to be essential to form episodic memories, possesses neurons that explicitly mark moments in time.

We add a previously unidentified finding to this work by showing that individual primate hippocampal neurons not only track time, but do so only when specific contextual information (e.g., object identity/location) is cued.”

As the study may apply to humans, it would follow that accessing a memory’s specific context would be a necessary part of accessing a full memory.

http://www.pnas.org/content/111/51/18351.full “Context-dependent incremental timing cells in the primate hippocampus”

Sorry to disable comments, but this post has somehow become a spam target. Readers can comment on Our memories have contexts with specific places and times which incorporates this study’s findings.

The need for a mother’s love

gettingwell4 4-5 stars Advanced knowledge, Brain development

BabyGorilla
This 2014 wild chimpanzee study demonstrated how necessary it was to have a mother’s “nourishment, transportation, warmth, protection, and socialization,” in other words, a mother’s love, during infancy and early childhood.

http://www.pnas.org/content/111/51/18189.full “Early social exposure in wild chimpanzees: Mothers with sons are more gregarious than mothers with daughters”

Problematic research on human brain development

gettingwell4 < 0 Detracted from science, Brain development, Cerebrum, Limbic system , ,

This 2013 UK human study provided details of the growths of infants’ cerebral and limbic system structures. With 55 of the 65 infants in the study born prematurely, the UK researchers found:

“Rapidly developing cortical microstructure is vulnerable to the effects of premature birth, suggesting a mechanism for the adverse effects of preterm delivery on cognitive function.”

The infants’ first set of measurements were taken from 27 to 46 weeks after birth. Follow-up measurements were taken when the infants were two years old.

Only the politically-correct adverse effects on brain development were included in the study, which led to the researchers making only politically-correct findings. Is this what we want from publicly funded scientific research?

  • Although 40 of the 65 infants experienced Caesarian deliveries, no attempt was made by the researchers to study any effects on brain development of their delivery method, an omission presumably due to the political incorrectness of suggesting any adverse effects to non-vaginal deliveries.
  • Similarly disregarded for analysis were the effects on brain development in 14 infants of preeclampsia, a serious complication of pregnancy associated with the development of high blood pressure and protein in the urine.
  • Also disregarded for analysis were the effects on brain development in 13 infants of chorioamnionitis, a condition in pregnant women in which the membranes that surround the fetus and the amniotic fluid are infected by bacteria.

Further, was this all we should expect from the peer review process? The data was presumably there for the reviewers to go back to the researchers and suggest analysis of something other than the predetermined agenda.

http://www.pnas.org/content/110/23/9541.full “Development of cortical microstructure in the preterm human brain”