Thalamus

The thalamus part of the limbic system has a critical period for connections

gettingwell4 2-3 stars Required further work, Anterior cingulate cortex, Brain development, Cerebrum, Limbic system, Lower brain, Primal Therapy, Thalamus , , ,

This highly-jargoned 2015 UK study found that connections made by the thalamus of the developing human fetus had a critical period of the last trimester of womb-life. Babies born before the 33rd week of gestation experienced thalamic disconnections compared with normal-term babies and adults. The disconnections increased with a shorter womb-life.

The thalamus of premature babies also developed stronger connections with areas of the face, lips, tongue, jaw, and throat. They presumably needed these connections for survival actions such as breathing and feeding that aren’t a part of the last trimester of womb-life.

The study confirmed that the structures of thalamic connections of normal-term babies were very similar to those of adults. The study added to the research that shows that human limbic systems and lower brains closely approximate their lifelong functionalities at the normal time of birth.

It was difficult to measure the thalamus at this stage of life with current technology, and the researchers had to discard over two-thirds of their results. The researchers recommended monitoring these premature babies for difficulties in later childhood that may be caused by their early-life experiences.

Why would this monitoring recommendation apply to just the study’s subjects? We know from other studies that a main purpose of thalamic connections is to actively control and gate information to and from the cerebrum.

Would it make sense for a medical professional to disregard any patient’s birth history if they had problems in their brain’s gating functions or connectivity?

One researcher said:

“The ability of modern science to image the connections in the brain would have been inconceivable just a few years ago, but we are now able to observe brain development in babies as they grow, and this is likely to produce remarkable benefits for medicine.”

This study’s results provided evidence for a principle of Dr. Arthur Janov’s Primal Therapy: the bases for disconnection from aspects of oneself are often set down during gestation. The “remarkable benefits for medicine” are more likely to be along the lines of what I describe in my Scientific evidence page.

http://www.pnas.org/content/112/20/6485.full “Specialization and integration of functional thalamocortical connectivity in the human infant”

Kids who have a larger and better-connected hippocampus learn math better when tutored

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

This 2013 Stanford study of 24 eight- and nine-year-old children found that measurements of limbic system areas predicted how well the 11 boys and 13 girls would respond to 8 weeks of one-on-one math tutoring!

“Pretutoring hippocampal volume predicted performance improvements. Furthermore, pretutoring intrinsic functional connectivity of the hippocampus with dorsolateral and ventrolateral prefrontal cortices and the basal ganglia also predicted performance improvements.

Brain regions associated with learning and memory, and not regions typically involved in arithmetic processing, are strong predictors of responsiveness to math tutoring in children. More generally, our study suggests that quantitative measures of brain structure and intrinsic brain organization can provide a more sensitive marker of skill acquisition than behavioral measures.”

None of the assessments, such as IQ and working memory tests, predicted how much benefit a child would receive from one-on-one math tutoring. The 16 children in the control group who didn’t receive one-on-one math tutoring didn’t improve their math performance over the 8-week period. Adults use different brain areas when solving math problems.

Much of the news coverage was from vested interests who dismissed the findings. A typical headline was “Your child’s brain on math: Don’t bother?”

The No Child Left Behind people were concerned that science could predict that some children were better suited to math tutoring than others. Psychiatrists and psychologists responded with general dismissals like small sample size, and the journalist let that stand without asking them how they disagreed with any of the specific P-, T- and other values found in the study’s supplementary material.

The researchers were careful to invoke a politically-correct meme of “individual differences“ 19 times, including the study’s title!

“Individual differences” isn’t a causal explanation, however. The journalist whiffed and also gave a pass to the researchers on this uninformative-but-PC meme.

It certainly would have been within the scope of this study for the researchers to inquire further into causes for the findings. It possibly could have informed us of causal factors had the children’s test battery included emotional content, as did the subjects in the Early emotional experiences change our brains: Childhood maltreatment is associated with reduced volume in the hippocampus study.

http://www.pnas.org/content/110/20/8230.full “Neural predictors of individual differences in response to math tutoring in primary-grade school children”

Epigenetic DNA methylation of the oxytocin receptor gene affected the perception of anger and fear

gettingwell4 2-3 stars Required further work, Amygdala, Anterior cingulate cortex, Brain development, Brain hemispheres, Cerebrum, Epigenetics, Hippocampus, Limbic system, Neurochemicals, Oxytocin, Thalamus ,

This 2015 Virginia human study:

“Reveals how epigenetic variability in the endogenous oxytocin system impacts brain systems supporting social cognition and is an important step to better characterize relationships between genes, brain, and behavior.”

The researchers did a lot of things right:

  • They studied a priori selected brain areas, followed by whole brain analyses;
  • Their subjects were carefully selected

    “Because methylation levels have been shown to differ as a function of race, we restricted our sample to Caucasians of European descent”

    but they didn’t restrict subjects to the same gender;

  • They acknowledged as a limitation:

    “A lack of behavioral evidence to reveal how these epigenetic and neural markers impact the overt social phenotype.”

One thing on which I disagree with the researchers is their assessment of what needs to be done next. Their news release stated:

“When imagining the future possibilities and implications this DNA methylation and oxytocin receptor research may have, the investigators think a blood test could be developed in order to predict how an individual may behave in social situations.”

Nice idea, but the next step should be to complete the research. The next step is to develop evidence for how the oxytocin receptor gene became methylated.

The subjects had a wide range of DNA methylation at the studied gene site – from 33% to 72% methylated!

Why?

At the same gene site:

“There was a significant effect of sex such that females have a higher level of methylation than males.”

Why?

Given these significant effects, why was there no research into likely causes?

Aren’t early periods in people’s lives the most likely times when the “Epigenetic modification of the oxytocin receptor gene” that “influences the perception of anger and fear in the human brain” takes place?

Wouldn’t findings from research on the subjects’ histories potentially help other people?

http://www.pnas.org/content/112/11/3308.full “Epigenetic modification of the oxytocin receptor gene influences the perception of anger and fear in the human brain”

If you had a disease, would you agree to treatment where you became a lab rat?

gettingwell4 2-3 stars Required further work, Amygdala, Limbic system, Thalamus ,

This 2015 Czech research studied individual neurons in an area of the limbic system of Parkinson’s disease patients. The findings corroborated several findings of previous research, such as:

“We confirm the importance of the subthalamic nucleus as a hub within the limbic circuitry involved in both emotional valence and arousal processing as in two functionally and spatially segregated systems.”

This statement summed up the study for me:

“Several factors could affect our results and reduce the inferences that can be drawn with regards to the physiology of emotional processing and the role of the subthalamic nucleus in the limbic circuits.

One such factor is that the study was conducted with Parkinson’s disease patients, who are known to have a widespread central nervous system pathology and to experience problems in emotional processing.”

The current study referenced The amygdala is where we integrate our perception of human facial emotion study, which similarly used the opportunity of patients with electrodes implanted for deep-brain stimulation to study individual neurons in the amygdala. However, a design difference was that the amygdala study had healthy control subjects in addition to patients, which led to fewer potential limitations on their findings.

Also referenced was a summary study entitled Exploring emotions using invasive methods: review of 60 years of human intracranial electrophysiology. Despite excluding studies of decision making, reward processing, learning, mood disorders, and pain experiences, it didn’t demonstrate that 60 years of experiments using implanted electrodes in the brains of people with epilepsy had substantially advanced science, other than confirming what fMRI and animal research had shown.

I’m not sure how I would feel if I had a disease where the physicians treated my symptoms in such a way that I became a lab rat for research that wasn’t groundbreaking. Do people with epilepsy and Parkinson’s disease have treatments available that factually resolve the underlying causes?

http://www.pnas.org/content/112/10/3116.full “Distinct populations of neurons respond to emotional valence and arousal in the human subthalamic nucleus”

Losing track of what are symptoms and what are causes with serotonin and stress

gettingwell4 0-1 star Wasted resources, Limbic system, Neurochemicals, Serotonin, Stress, Thalamus ,

I’m starting to appreciate just how far down the rabbit hole researchers can go when they focus on symptoms and ignore causes.

This 2014 Duke study found that low-serotonin mice were more susceptible to stress than normal mice.

Okay so far, except that the study used transgenic mice that only had 20-40% of normal serotonin.

Humans most often develop low-serotonin symptoms for causes other than genetics, such as a second-order result of being subjected to childhood maltreatment and stress.

Use of the low-serotonin-due-to-genetics mice may have misdirected the researchers to lose focus that their ultimate task was to find ways that their research can help humans. If helping humans was the researchers’ focus, it may have occurred to them to show how stress caused “something” that caused low serotonin.

A second finding was that following exposure to stress, the low-serotonin mice didn’t respond to a standard antidepressant, fluoxetine. SSRI medications usually act to increase serotonin transmission, i.e. treat the symptom of low serotonin.

Stress was again not viewed as a cause of “something” that caused low serotonin. Stress was viewed as the reason that the medication didn’t work.

If helping humans was the researchers’ focus, it may have occurred to them that humans may not need medication to treat the low-serotonin symptom if the “something” that stress caused that keeps the low-serotonin symptom in place was removed.

A third finding was that inhibiting the lateral habenula area (proximal to the thalamus) with a drug relieved some depression-like behavior of the low-serotonin mice.

Okay, but one of the researchers went on to say:

“The next step is to figure out how we can turn off this brain region in a relatively non-invasive way that would have better therapeutic potential.”

Would everything would be fine if the low-serotonin mice just stopped displaying symptoms such as the depression-like behavior? Why no focus on causes, no forward thinking that maybe humans wouldn’t want part of their limbic system that performed many other functions to “turn off” just to suppress a symptom?

The researchers apparently didn’t realize their situation viz-à-viz the rabbit hole, as they circled back to the initial finding to develop a fourth finding – a possible reason that low-serotonin mice were more susceptible to stress was because a signaling molecule, β-catenin, wasn’t produced in a pathway that may be involved in resilience.

The news coverage added one more researcher quote:

“If we can identify what’s both upstream and downstream of β-catenin we might be able to come up with attractive drug targets to activate this pathway and promote resilience.”

If we treat a third-order symptom, the signaling molecule, everything will be alright?

Which leads me to ask:

http://www.pnas.org/content/112/8/2557.full “Brain 5-HT deficiency increases stress vulnerability and impairs antidepressant responses following psychosocial stress”

Research on brain areas involved when we imagine people, places, and pleasantness

gettingwell4 2-3 stars Required further work, Amygdala, Beliefs, Brain hemispheres, Cerebrum, Hippocampus, Limbic system, Thalamus ,

This highly jargoned 2014 Harvard study was on how people imagine that they’ll feel in the future.

One of the researchers was an author of:

I was surprised that this study also didn’t ignore the limbic system to the point to where the researchers wouldn’t even bother to measure important areas.

Limbic system areas that process people were different than those that process places. For example, the data in Table S4 showed that the subjects’ left amygdala and hippocampus were more activated when simulating future familiar people, whereas their right hippocampus was more activated when simulating future familiar places.

The researchers may have improved the study’s findings if they were informed by studies such as the Hippocampus replays memories and preplays to extend memories into future scenarios, which found that “place” cells in the CA1 segment of the hippocampus preplay events that imagine future scenarios of:

“Novel spatial experiences of similar distinctiveness and complexity.”

Such information may have helped to disambiguate one of the study’s findings in Table S5, that both sides of the subjects’ hippocampus were more activated than other brain regions when simulating both familiar people and places.

The researchers got a little carried away in broadly attributing most of the study’s findings to the ventromedial prefrontal cortex. For example, the data in Table S6 showed that the thalamus was more activated when the subjects anticipated positive pleasantness, but not when negative effects were anticipated.

We know from Thalamus gating and control of the limbic system and cerebrum is a form of memory that this is normally how the thalamus part of the limbic system actively controls and gates information to and from the cerebrum. Their data showed thalamic gating in operation:

  • Active when passing along pleasantness to cerebral areas, and
  • Passive when blocking unpleasantness from cerebral areas.

Also, I didn’t see how the researchers differentiated some of their findings from a placebo effect. For example, Using expectations of oxytocin to induce positive placebo effects of touching is a cerebral exercise found:

“Pain reduction dampened sensory processing in the brain, whereas increased touch pleasantness increased sensory processing.”

This was very similar to the above finding involving the thalamus.

http://www.pnas.org/content/111/46/16550.full “Ventromedial prefrontal cortex supports affective future simulation by integrating distributed knowledge”

Using expectations of oxytocin to induce positive placebo effects of touching

gettingwell4 2-3 stars Required further work, Amygdala, Beliefs, Brain hemispheres, Limbic system, Neurochemicals, Oxytocin, Thalamus

This 2013 Scandinavian study detailed which brain structures were involved when fooling oneself about actual sensations in favor of expected sensations.

It was hilarious how the researchers used studies of oxytocin to create expectations in the subjects:

“To induce expectation of intranasal oxytocin’s beneficial effects on painful and pleasant touch experience, participants viewed a 6-min locally developed video documentary about oxytocin’s putative prosocial effects such as involvement in bonding, love, grooming, affective touch, and healing. As all of the material was based on published research, there was no deception. The video concluded that a nasal spray of oxytocin might enhance the pleasantness of:

  • (i) stroking and
  • (ii) warm touch, and
  • (iii) reduce the unpleasantness of pain.”

Other items:

  • Only the placebo effects for the warm and pain-reducing touches were statistically significant, not the stroking touch;
  • The a priori brain areas monitored in the “sensory circuitry” included the thalamus and were all in the right brain hemisphere;
  • The a priori brain areas monitored in the “emotional appraisal circuitry” included the amygdala.

One way the researchers summarized the study was:

“Pain reduction dampened sensory processing in the brain, whereas increased touch pleasantness increased sensory processing.”

This finding demonstrated how the thalamus part of the limbic system actively controls and gates information to and from the cerebrum, similar to the Thalamus gating and control of the limbic system and cerebrum is a form of memory study.

There was a terminology problem in the study, evidenced by statements such as:

“We induced placebo improvement of both negative and positive feelings (painful and pleasant touch).”

Touch is a sensation, not a feeling or emotion. This placebo study created expectations of sensations in the subjects’ cerebrums, not expectations of emotions.

Also, including parts of the limbic system such as the amygdala in the “emotional appraisal circuitry” didn’t mean that the researchers studied feelings or emotions. We know from research summarized in the Conscious mental states should not be the first-choice explanation of behavior study that:

“Neither amygdala activity nor amygdala-controlled responses are telltale signatures of fearful feelings.“

The current study cast additional light on the dubious Problematic research on human happiness study. Those researchers were fooled by a positive placebo effect!

http://www.pnas.org/content/110/44/17993.full “Placebo improves pleasure and pain through opposite modulation of sensory processing”

The thalamus’ role in coordinating REM sleep stages

gettingwell4 2-3 stars Required further work, Brainstem, Limbic system, Lower brain, Memory, Thalamus

This 2013 human study provided more details about dream sleep. The thalamus portion of the limbic system coordinates REM stages, which play critical roles in learning and memory.

This study also noted that science assigns no functions to dreams themselves, which was the first I’d heard of it.

http://www.pnas.org/content/110/25/10300.full “Rhythmic alternating patterns of brain activity distinguish rapid eye movement sleep from other states of consciousness”

Thalamus gating and control of the limbic system and cerebrum is a form of memory

gettingwell4 5+ stars Premium, Cerebrum, Hippocampus, Hypothalamus, Limbic system, Memory, Thalamus ,

This 2014 German rodent study showed how the thalamus actively controlled and gated information to and from the cerebrum.

The researchers elaborated in news coverage on how thalamic control and gating represented a form of memory:

“Q. When asked if, given that

  1. Sensory signals en route to the cortex undergo profound signal transformations in the thalamus,
  2. A key thalamic transformation is sensory adaptation in which neural output adjusts to statistics and dynamics of past stimuli, and
  3. The thalamus, hypothalamus and hippocampus being part of the limbic system, might memory reconsolidation play a role in the cortico-thalamic pathway?

A. “It’s conceivable that the cortico-thalamic pathway is subject to long term plasticity,” Groh conjectures. “In fact, on a synaptic level, these inputs can change their strength and retain adjusted strengths for long periods. This process represents another – albeit much slower – form of adaptation which some interpret as memory.”

Q. Conversely, might the thalamic-cortical pathway affect memory?

A. “If particular sensory-evoked activity patterns would cause long-term changes in the cortico-thalamic pathway, and thereby change the way incoming signals are processed before reaching the cortex,” he opines, “then this would indeed reflect a form of information storage.”

In other words, there are ways in addition to our usual ideas about memory that the limbic system remembers.

Other items in news coverage included:

“Rodents, cats, primates and humans show a common architecture of two feedback pathways from cortex to thalamus in the auditory, visual and somatosensory (but not olfactory) systems.

In this study we looked at processing of touch information, and we’d like to know how homologous pathways affect visual or auditory processing. It’s fascinating that despite fundamental differences between visual, auditory and somatosensory signals, basic layouts of thalamocortical systems for each modality are quite similar.”

Other areas of research that might benefit from their study include any medical research involving the thalamocortical system that might involve inappropriate gating of sensory signals.

For a given stimulus, output neural response will not be static, but will depend on recent stimulus and response history.”

http://www.pnas.org/content/111/18/6798.full “Cortical control of adaptation and sensory relay mode in the thalamus”

Rebooting the brain with anesthesia: Implications for Primal Therapy and evolution

gettingwell4 4-5 stars Advanced knowledge, Anterior cingulate cortex, Brain development, Brainstem, Hypothalamus, Limbic system, Locus coeruleus, Lower brain, Memory, Primal Therapy, Thalamus , , ,

Here are some paragraphs from a 2013 summary article of 105 studies entitled Evolution of consciousness: Phylogeny, ontogeny, and emergence from general anesthesia:

“The emergence of consciousness (from anesthesia) (as judged by the return of a response to command) was correlated primarily with activity of the brainstem (locus coeruleus), hypothalamus, thalamus, and anterior cingulate (medial prefrontal area). Surprisingly, there was limited neocortical involvement that correlated with this primitive form of consciousness.

In the sleep study, midline arousal structures of the thalamus and brainstem also recovered function well before cortical connectivity resumed. Thus, the core of human consciousness appears to be associated primarily with phylogenetically ancient structures mediating arousal and activated by primitive emotions, in conjunction with limited connectivity patterns in frontal–parietal networks.

The emergence from general anesthesia may be of particular interest to evolutionary biology, as it is observed clinically to progress:

  1. from primitive homeostatic functions (such as breathing)
  2. to evidence of arousal (such as responsiveness to pain or eye opening)
  3. to consciousness of the environment (as evidenced by the ability to follow a command)
  4. to higher cognitive function.

Regarding ontogeny of H. sapiens, peripheral sensory receptors are thought to be present from 20 wk of gestation in utero. The developmental anlage of the thalamus is present from around day 22 or 23 postconception, and thalamocortical connections are thought to be formed by 26 wk of gestation. Around the same time of gestation (25–29 wk), electrical activity from the cerebral hemispheres shifts from an isolated to a more continuous pattern, with sleep–wake distinctions appreciable from 30 wk of gestation.

Both the structural and functional prerequisites for consciousness are in place by the third trimester, with implications for the experience of pain during in utero or neonatal surgery.“

I recently came out of anesthesia after being anesthetized for three hours during rotator cuff surgery. I felt pain, and went into a primal reliving of a painful memory.

I interpret the event as a reliving of my birth experience because of the following:

  • The beginning point was complete anesthetization as it was at my birth. My mother was completely anesthetized, so I, weighing less than one twentieth of her, was also completely anesthetized.
  • I felt a great urge and impulse to “get out” as it was at my birth. The attending nurse told me the next day that she called over another person to help her restrain me in the post-op chair.
  • I had a great need for oxygen and started breathing rapidly as it could have been at my birth. The nurse told me the next day that she was already giving me oxygen, and per the monitors, I didn’t need more oxygen.
  • I had to frequently “spit up” as it could have been at my birth. There was nothing in my current situation to cause me to expectorate.
  • My lower brain and limbic system were in control, as I thrashed, cried and moaned. I probably used primarily the same brain areas as what were the developed parts of my brain at birth.

The attending nurse told me the next day when I called her that she followed the established protocol, which was to get me out of the experience. She intentionally distracted me away from my pain. I was instructed to sit still, to think of some place pleasant, and to calm down.

I heard her as though she was at the other end of a tunnel at first, and then started to comply as I regained cognitive awareness.

I understand how such a powerful event could present a danger to a patient. It didn’t occur to me until the next day to tell the nurse of relevant history, that I’ve had relivings while in therapy, and wasn’t in the same danger that her regular patients may have been.

Even if I had said something, however:

  • Neither the anesthesiologist nor the attending nurse had a method of understanding how an evolutionary-determined sequential process – such as rebooting a person’s brain after prolonged anesthesia – may have therapeutic benefits.
  • They had no training to recognize aspects of neurobiologic therapeutic value in what was going on inside of me during this event, as a therapist in Dr. Arthur Janov’s Primal Therapy has.
  • The default response per medical protocol would be to shut down a patient’s expressions of their feelings.

As a result, my experience of this event was pretty much the opposite of what happens in Primal Therapy. Although I didn’t feel harmed, my reliving wasn’t therapeutic, as previous re-experiencings had been. The reliving’s progression through my levels of consciousness was purposely interrupted, and approached from a non-therapeutic direction.

Unlike my experience of coming out of anesthesia, Dr. Arthur Janov’s Primal Therapy isn’t something the patient is thrown into and potentially overwhelmed by their feelings. It’s a gradual process where the patient is in control.

This summary study showed that existing science is already in alignment with the background of Primal Therapy, that the core of human consciousness is in the limbic system and lower brain structures. My anesthesia experience showed that medical professionals are familiar with at least the outward signs of a primal reliving.

The challenge seems to be how to use this complementary knowledge for people’s benefit. What can be done with therapeutic re-experiencing so that people aren’t burdened with the continuing adverse effects of traumas?

How can scientists and medical professionals get the eyes to see what’s in front of them?