Wednesday, February 14, 2024

Why are "Love Languages" so popular, when they're completely inaccurate?


I joined an online dating site a few months ago.1 Besides being asked about my sun, moon, and rising signs (?), I was puzzled by the following question.2



My love language? I'm supposed to choose only one answer? 

Gary Chapman has been a pastor at Calvary Baptist Church in Winston-Salem, NC for 50 years. In 1992, he published a book based on his experience of advising heterosexual couples on the best ways to have a harmonious marriage. His notion of 5 Love Languages is based on conservative Christian gender roles, although subsequent editions are less blatantly misogynistic. Nonetheless, the popularity of his ideas extends well beyond this initial demographic and has (ironically) invaded very Queer spaces.

Anyone can take the The Love Language® Quiz. I quit after the first question because it forces you to choose between a loving note/text/email for no special reason and a hug. Under any and all circumstances. 

Even my cat has more than one love language. There are three, which vary according to her needs:3

  • petting
  • play
  • food

And as humans, why must we limit ourselves to the five choices above, when the possibilities are endless? Here are some examples.4


New Love Languages
by James Folta and Kasey Borger

Deciding Where to Eat
Let your stressed-out partner know you’re for real by choosing a spot to eat. This is a love language that every single person desires, but almost no one can express. Looks like it’s frozen pizza again.

Talking About Your Commute
There is an extremely high concentration of individuals with this love language in New York and LA. Going on and on about trains, or highways, or traffic, or “I think it took me 25 minutes last time, but this time it took 35 — weird” is the only way this group can show their sweetie they care.

Explaining How You Feel About Facebook
Some people can only express their love by unpromptedly exclaiming that they’re going to delete their Facebook, and for real this time. Studies show this can be hard to discern as a love language because it is insufferable.

 

...and my personal favorite:

Replying to But Not Liking Tweets
This is a dark and horrific way to express affection, but we must begrudgingly acknowledge it.

Love Languages on a Likert Scale

As any decent social psychologist will tell you, The Love Language® Quiz has poor psychometric properties, meaning that the validity and reliability of the measurement instrument is very low. A remarkable number of studies have investigated the concept of love languages, and there is no empirical support for the idea, as recently reviewed by Impett, Park, and Muise (2023). A major issue is the way that Chapman frames his questions (as forced choices between two options). Instead, rating each item on continuous Likert-type scales reveals no correlation between scores on the quiz and scores on the continuous measure. These findings discount the notion that each person has a primary love language and illustrate that people value all five love languages but perhaps in different contexts, said Impett and colleagues.


So why are Love Languages so popular?
“If I had to pick one reason why I think many couples find Chapman’s book to be helpful,” says [co-author Haeyoung Gideon] Park, “it is not because they learned their own or their partner’s love language but because it gets people to identify any currently unmet needs in their relationship and opens up lines of communication to address those needs.”

 

Footnotes

1 I'm not saying which one. I'm in a demographic that absolutely no one cares about.

2 Clearly, I do not belong in my own demographic.

3 Sometimes, she enjoys more than one at the same time (e.g., petting while eating).

4 When forced to choose, my preferred love language is Sarcasm and Hyperbole, which does not make me popular with the online dating set.



Reference

Impett EA, Park HG, Muise A. (2023). Popular Psychology Through a Scientific Lens: Evaluating Love Languages From a Relationship Science Perspective. Current Directions in Psychological Science. 2023 Dec 7:09637214231217663.
 
- click to enlarge Table - 
 


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Tuesday, May 09, 2023

I'm thinking about moving this blog...

 ...to another platform.

 

Hi, it's been a while. I haven't written anything this year. My last post was December 31, 2022.

The main reason is that I've had to deal with more loss and grief in my life. Someone close to me was diagnosed with cancer, endured months of radiation and chemotherapy, and died anyway.1 I've also had some deflating garbage to wade through at work. My enthusiasm for doing anything has been rather low.

Besides all that, Blogger is a terrible platform for blogging. The interface changed a while a back and ever since then, composing in the little box has been unpleasant. It takes forever to get the formatting and spacing right. I could modernize the look from a “classic” theme 2 to one that has a “Layout” view...

 


...but that doesn't improve the writing experience.


So. I already have a WordPress blog. I may start posting there. The old neurocritic.blogspot.com site would become an archive of posts from 2006 2022.

 

The bigger question is whether I have anything relevant to say any more. 

 

Footnotes

1 ...less than three months later. If you ask me, the cause of death WAS the treatment (and its side effects). 

2 “Hey there, 2004 wants their Rounders template back.” An SEO Guy even blogged about 11 Huge Reasons to AVOID Blogspot in 2023.

3 There are other platforms, sure. In a hilarious meta-example, a post on Medium provided a tutorial on Substack, which started as a platform for e-mail newsletters (whether monetized or not). But it also has a very blog-like look here's Margaret Atwood's, for example. Now they have Substack Notes, which is in the running as yet another Twitter replacement. Here's a thread on dumplings.

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Saturday, December 31, 2022

Neuroscience Trend Forecasters


As 2022 draws to a close, the SNL Trend Forecasters have agreed to divulge their predictions for the most — and the least exciting research fads for the New Year.


The Neurocritic: How do you guys predict today's most popular neuroscience trends? 

Trend Forecasters: Oh, well we have 4,000 computers, they're all big they all make charts and they beep LOUD.

TN: Let's get started!


In: posterior cingulate cortex

Hey Posterior Cingulate — we see you! You're fresh, you're mysterious, you're misunderstood. But we know you exist far beyond the default fashion mode. The new tripartite view proposes...

...that the broader PCC region contains three major subregions — the dorsal PCC, ventral PCC and retrosplenial cortex — that respectively support the integration of executive, mnemonic and spatial processing systems. This tripartite subregional view reconciles inconsistencies in prior unitary theories of PCC function and offers promising new avenues for progress.

 

Out: anterior cingulate cortex

Get behind me, you tired brain region. Think you can do everything? Well the list of your supposed functions is wildly implausible. We've looked at PubMed and found mental fatigue, prediction of non-violent felony rearrest in women, amyloid-β-related increases in empathic concern, experimental odontogenic pain, gravitational perception, chronic itch, RDoC social constructs, and modulation of synaptic plasticity in exercise interventions for post-stroke pain.

 


 

In: claustrum

Claustrum, we're in love with you and it's not only because of the holidays. You're connected to everything and everyone.

Santa Claustrum

 

Initial speculation claimed you were responsible for consciousness (Crick & Koch, 2015), but subsequent studies in human epilepsy patients showed no alterations in consciousness with unilateral or bilateral electrical stimulation (Bickel & Parvizi, 2019). Instead, you're critical for cognitive control. The fresh functional model is called network instantiation in cognitive control (Madden et al., 2022).

Researchers at the University of Maryland School of Medicine ... now posit that Crick may have been incorrect: They developed a new theory — built on data — that the claustrum behaves more like a high-speed internet router, taking in executive commands from “boss” areas of the brain’s cortex that forms complex thoughts to generate “networks” in the cortex.

 

The most exciting recent work (in mice) has shown that claustro-cortical circuits are organized into functional modules (McBride et al., 2022)...

  • Frontal areas are more inhibited, while posterior areas are more excited
  • Upper layers are more excited, while deeper layers are more inhibited 
...and connect cortical network motifs (Qadir et al., 2022)
  • Frontal cortices are synaptically connected to posterior cortices through claustrum
  • Two claustrum projection neuron subtypes support trans-claustral circuits
  • Trans-claustral circuits resemble a frontoposterior cortical network motif

Out: reinforcement learning and mesolimbic dopamine



 

Your superiority complex is tired, temporal difference error. We know you consider yourself the “biggest success story in computational neuroscience.” But every week a new finding prompts a mathematical tweak and an update of your impenetrable model.

‘teaching signal’ ‘learning model’ ‘model-free’ ‘cached values’ ‘ramps’ ‘bumps’ ‘belief states’ ‘vector RPE’ ‘DA dip of disappointment

Go to bed, TD. You have to get up early. For a flight TO HELL!



 
 

In: HippoCamera

You spent years developing your brilliant smartphone app that improves memory in older adults, drawing on the basic science of hippocampal replay (e.g., speeding up 24 sec video clips by 3×).



Autobiographical memory cues are created by recording an 8 sec audio cue to accompany a 24 sec video recording of a daily event, which is rated for significance. In your recent paper, fMRI scanning occurred after a two week or 10 week intervention. In comparison to baseline (non-reviewed) events, repeated replay of autobiographical memory cues enhanced episodic recollection and increased the differentiation of activity patterns in the hippocampus in older adults (Martin et al., 2022). Bravo, HippoCamera! Take a bow Barense, Honey, and Martin!

 

Out: Brain Behavior Quantification and Synchronization (BBQS)

BRAIN Initiative,2 you're so far behind the times that YOU ARE OUT. Didn't you get the memo that Neuroscience Needs Behavior back in 2017? Or read the review on Quantifying Behavior [in worms and flies] to Solve Sensorimotor Transformations, which covered papers going back to 2008 and earlier? The patented HippoCamera was developed behind your back with funding from the Canadian government and private foundations. And the clever use of remote memories recorded by the 1 Second Everyday app (Bainbridge & Baker, 2022) was funded by NIH Intramural funds. The fact that you waited until 2023 to fully announce BBQS projects in humans and non-humans speaks volumes to the value you place on understanding behavior. GO TO BED!


In: neuropeptide maps of human prefrontal cortex

One recent uptick in human brain complexity was revealed from analysis of postmortem tissue in 17 subregions of prefrontal cortex (PFC). Zhong and colleagues (2022) found that 60 neuropeptides and 60 neuropeptide receptors are expressed in at least one of the PFC subregions. The data are freely available and incorporated into the Human Protein Atlas which has about 5 million individual web pages. The authors encouraged efforts to explore these neuropeptide receptors as potential targets for drug development in neurology and psychiatry, which has been neglected by pharmaceutical companies in recent years.


Out: functional neuroimaging in psychiatry
 

You're a failure, psychiatric neuroimaging!! Nour, Liu, and Dolan wrote a 20 page paper detailing your many shortcomings and faults. For instance, explanatory aspirations in resting-state studies are laughable:

“...bridging a gap between descriptive accounts of neural data and psychopathology requires a model that relates network properties ... to specific computational processes. Absent such a model, we argue that further large-scale data collection will be insufficient to yield breakthroughs in probing a fundamental understanding of cognition or psychiatric illness.

 We needn't go further than listing other direct quotes from their paper:

  • “...functional neuroimaging plays no role in clinical decision making.”
  • “While the computational psychiatry literature has identified associations between model-informed neural activity and psychiatric variables, effective clinical translation has been lacking.” 
  • “Casting a cold eye on the psychiatric neuroimaging literature invites a conclusion that despite 30 years of intense research and considerable technological advances, this enterprise has not delivered a neurobiological account (i.e., a mechanistic explanation) for any psychiatric disorder, nor has it provided a credible imaging-based biomarker of clinical utility.”
 
Ouch! You've done nothing for us, psychiatric neuroimaging. You haven't even embraced the correct level of analysis (i.e. manifolds). GO TO BED!

[In again: manifolds]


In: Synchron

Synchron, all the other billionaires are backing you, to the tune of $75 million! In a remarkable advance towards greater independence for paralyzed persons, the Stentrode, an endovascular brain computer interface (BCI), received Breakthrough Device designation from the FDA in August 2021. 

 

Stentrode™ (endovascular implant)

 

The minimally invasive BCI was developed with funding from DARPA (among others), and initial results from sheep were reported in Nature Biotechnology (Oxley et al., 2016). Its placement in the superior sagittal sinus (via the jugular vein) produces high-fidelity recordings from motor cortex without the need for risky cranial surgery. The brain.io™ motor neuroprosthesis transmits cortical signals from the Stentrode to a receiver implanted in the chest, and a machine learning algorithm decodes the neural activity and translates the signals to digital commands.

 

Oxley et al. (2021)

 

Two paralyzed participants with ALS achieved typing click selection accuracy of 93% within 86 days and 71 days of machine-learning supervised training (Oxley et al., 2021). Typing rate was relatively slow (13.8 and 20.1 correct characters per minute, respectively) in comparison to some other BCI cases, but those all entailed craniotomies.1 Nonetheless, both participants were able to text, e-mail, browse the internet, shop online, and manage finances (Oxley et al., 2021). The COMMAND Early Feasibility Study is an ongoing clinical trial of the Synchron device that will enroll six patients.


In: Mastodon

Because everyone needs an alternative social media site.


Out: Neuralink

Neuralink, you're out! So go back to hell. Stop flaunting your wealth, Neuralink. We all know you have to die for your hubris. You think you'll have FDA approval in six months, but that's what you said in 2019. Many of your claims are sheer fantasy, like you'll be able to cure everything from addiction to strokes.


from Neuralink Progress Update, Summer 2020

 

Your Fall 2022 update was more technically impressive, but still claimed your device will be able to restore vision prompting eminent vision scientist Brian Wandell to call out this BS:

He [Musk] specifically said this would work for the congenitally blind because they still have a visual cortex.

Two hundred years of experiments on site restoration in human, and many fundamental cellular experiments of visual development and the limits of adult plasticity, show this is false.


Potential ethical concerns have been noted by UPenn Prof Anna Wexler. Finally, you're under investigation for possible animal welfare violations. Neuralink, if I see you in the street I'll stab you in the face.




 
What are your favorite neuroscience trends for 2023? What should be kicked to the curb?

 

Footnotes

1 Most notable was BrainGate participant T5, with an astonishing 90 characters per minute. Two microelectrode arrays were implanted in the hand area of the precentral gyrus, and neural activity produced by imagined handwriting was decoded and translated into text in real time (Willett et al., 2021).

2 hat tip to Drug Monkey.


References

Bainbridge, W. A., & Baker, C. I. (2022). Multidimensional memory topography in the medial parietal cortex identified from neuroimaging of thousands of daily memory videos. Nature Communications, 13(1), 1-16.

Bickel, S., & Parvizi, J. (2019). Electrical stimulation of the human claustrum. Epilepsy & Behavior, 97, 296-303.

Calhoun, A. J., & Murthy, M. (2017). Quantifying behavior to solve sensorimotor transformations: advances from worms and flies. Current opinion in neurobiology, 46, 90-98.

Crick, F. C., & Koch, C. (2005). What is the function of the claustrum?. Philosophical Transactions of the Royal Society B: Biological Sciences, 360(1458), 1271-1279.

Foster, B. L., Koslov, S. R., Aponik-Gremillion, L., Monko, M. E., Hayden, B. Y., & Heilbronner, S. R. (2022). A tripartite view of the posterior cingulate cortex. Nature Reviews Neuroscience, 01 Dec 2022.

Han, J. J. (2021). Synchron receives FDA approval to begin early feasibility study of their endovascular, brain‐computer interface device. Artificial Organs, 45, 1134-1135.

Krakauer, J. W., Ghazanfar, A. A., Gomez-Marin, A., MacIver, M. A., & Poeppel, D. (2017). Neuroscience needs behavior: correcting a reductionist bias. Neuron, 93(3), 480-490. 

Madden, M. B., Stewart, B. W., White, M. G., Krimmel, S. R., Qadir, H., Barrett, F. S., ... & Mathur, B. N. (2022). A role for the claustrum in cognitive control. Trends in Cognitive Sciences.

Martin, C. B., Hong, B., Newsome, R. N., Savel, K., Meade, M. E., Xia, A., ... & Barense, M. D. (2022). A smartphone intervention that enhances real-world memory and promotes differentiation of hippocampal activity in older adults. Proceedings of the National Academy of Sciences, 119(51), e2214285119.

McBride, E. G., Gandhi, S. R., Kuyat, J. R., Ollerenshaw, D. R., Arkhipov, A., Koch, C., & Olsen, S. R. (2022). Influence of claustrum on cortex varies by area, layer, and cell type. Neuron (Nov 4).

Nour, M. M., Liu, Y., & Dolan, R. J. (2022). Functional neuroimaging in psychiatry and the case for failing better. Neuron, 110(16), 2524-2544.

Oxley, T. J., Yoo, P. E., Rind, G. S., Ronayne, S. M., Lee, C. S., Bird, C., ... & Opie, N. L. (2021). Motor neuroprosthesis implanted with neurointerventional surgery improves capacity for activities of daily living tasks in severe paralysis: first in-human experience. Journal of neurointerventional surgery, 13(2), 102-108.

Qadir, H., Stewart, B. W., VanRyzin, J. W., Wu, Q., Chen, S., Seminowicz, D. A., & Mathur, B. N. (2022). The mouse claustrum synaptically connects cortical network motifs. Cell Reports, 41(12), 111860.

Zhong, W., Barde, S., Mitsios, N., Adori, C., Oksvold, P., Feilitzen, K. V., ... & Hökfelt, T. (2022). The neuropeptide landscape of human prefrontal cortex. Proceedings of the National Academy of Sciences, 119(33), e2123146119.

 

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Monday, October 31, 2022

Frankenstein's Hand


Just in time for Halloween, I had a hideous surgery to repair a fractured elbow. This entailed receiving a nerve block that made my hand feel like a dead appendage, which was quite spooky indeed.

 


 Spooky Dead Hand

  

I'm supposed to keep the arm elevated above my heart (which isn't conducive to sitting here and typing), so that is all for now.

 

Happy Halloween!


Actual e-mail sent to the post-op contact person the night of my surgery:

 

Read more »

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Friday, September 30, 2022

"And then a Plank in Reason, broke,"

 “I am dead.”

 

In terms of possible delusions in living human beings, Le délire des négations the nihilistic delusion that one is dead  evokes the most harrowing existence imaginable. The French neurologist Jules Cotard first described the syndrome that bears his name (1882, English translation):

I hazard the name of delirium of negations to designate the state of the patients ... in whom the negative disposition is carried to the highest degree. [They are] asked their name – they have no name; their age – they are ageless; where were they born – they were not born; ... if they have a headache, stomach ache, pain in some part of their body – they have no head, no stomach, some even have no body... For some the negation is universal, nothing exists anymore, they themselves are nothing.

 

Cotard presented the case of Miss X, a 43 year old woman with severe “melancholic anxiety” who tried to end her own life (1880, English translation):

...She affirms that she has neither brain nor nerves, nor chest, nor stomach, nor intestines; all that remains is the skin and bones of the body, disorganized (these are [her] own expressions). This delirium of negation extends even to the metaphysical ideas which were formerly the object of [her] firmest beliefs; She doesn't have a soul, God doesn't exist, neither does the devil. Miss X… being no more than a disorganized body, does not need to eat to live, she cannot die a natural death, she will exist eternally unless she is burned, fire being the only end...


Cotard delusion has been observed in a wide variety of psychiatric and neurological conditions, including psychotic depression, schizophrenia, encephalitis, subdural hemorrhage, arteriovenous malformations, migraine, Parkinson's disease, stroke, and epilepsy (Gerrans, 2022). From a neurobiological perspective, it's nearly impossible to construct a unified theory of the dysfunctional brain systems that underlie the delusion. Hence, some studies have focused on patients who manifest Cotard delusion after stroke, brain injury, or anti-NMDA receptor encephalitis for clues on potential brain regions that may be implicated in these cases. 

Two new papers describe the role of depersonalization an estrangement from one's body or self in Cotard delusion (Davies & Coltheart, 2022; Gerrans, 2022).


Absence disembodies — so does Death
Hiding individuals from the Earth
Superposition helps, as well as love —
Tenderness decreases as we prove —

Emily Dickinson


One prominent account of Cotard holds that people suffering from the delirium of negation are completely devoid of emotional responses. The nihilistic delusion is an attempt to make sense of this anomalous experience. Davies and Coltheart (2022) are critical of this view because there's no evidence that emotional reactivity is abolished in Cotard delusion. They also cite 12 case reports of patients who show a variety of affective states that collectively encompass anxiety, fear, guilt, distress, paranoia, aggression, agitation, anguish, despair, euphoria, grandiosity, irritability, sadness, and worry.

An alternate account places the anomalous experiences of depersonalization and derealization, rather than lack of emotion, as the central “surprising events” that trigger nihilistic delusions (Billon, 2016; Davies & Coltheart, 2022). These patients describe phenomena such as “I feel myself detached from my own body” and “feelings of unreality and difficulties in deciding whether events ... were real or just imagined”. The injured brain areas in these patients included insular cortex and right temporal-parietal regions.

A Death blow is a Life blow to Some
Who till they died, did not alive become —
Who had they lived, had died but when
They died, Vitality begun.

Emily Dickinson


In contrast, Gerrans (2022) proposes that depersonalization and Cotard delusion result from different ruptures in the sense of self. He provides an extensive and accessible review of the interoceptive active inference model and predictive coding of bodily states in the anterior insula cortex. Depersonalization may arise from imprecise interoceptive predictions, but reality testing remains intact. On the other hand, Cotard delusion represents a complete rupture from reality.

Within this framework, depersonalisation experience involves a selective failure to annex a class of experience to a largely intact hierarchical self-model. The Cotard delusion is a result of the destruction or degradation of that model. It is consistent with this view that there can be overlap between symptoms of depersonalisation disorder and Cotard syndrome, especially while the delusion develops because of nature of self-modelling. However the delusion reports the experience of human life without an intact regulatory self-model whereas in depersonalisation the self-model is largely intact.


A key component of the “depersonalization first, Cotard second” view should account for why the former is relatively common, while the latter is quite rare.

 

References

 
Cotard, J. (1880). Du Délire hypocondriaque dans une forme grave de la mélancolie anxieuse, mémoire lu à la Société médico-psychologique dans la séance du 28 juin 1880, par M. le Dr Jules Cotard.

Cotard, J. (1882). Du délire des négations. Arch de Neurol, 4, 282-296.
 
Davies, M., & Coltheart, M. (2022). Cotard delusion, emotional experience and depersonalisation. Cognitive Neuropsychiatry, 1-17.
 
 


 
I felt a Funeral, in my Brain,
And Mourners to and fro
Kept treading - treading - till it seemed
That Sense was breaking through -

And when they all were seated,
A Service, like a Drum -
Kept beating - beating - till I thought
My mind was going numb -

And then I heard them lift a Box
And creak across my Soul
With those same Boots of Lead, again,
Then Space - began to toll,

As all the Heavens were a Bell,
And Being, but an Ear,
And I, and Silence, some strange Race,
Wrecked, solitary, here -

And then a Plank in Reason, broke,
And I dropped down, and down -
And hit a World, at every plunge,
And Finished knowing - then -
 

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Wednesday, August 31, 2022

The Human Protein Atlas (Neuropeptide Edition)


The more you study the brain, the more unknowable it becomes. The level of complexity is baffling, and this is true whether the brain belongs to a human or a crab.1 The latest uptick in human brain complexity was revealed from analysis of postmortem tissue in 17 subregions of prefrontal cortex (PFC). Zhong and colleagues (2022) found that 60 neuropeptides and 60 neuropeptide receptors are expressed in at least one of the PFC subregions.

 

All the data are freely available (links are in the open access article) and incorporated into the Human Protein Atlas which has about 15 million individual web pages (according to Wikipedia).


Footnote

1 Marder et al., 2022:

There is a growing literature that suggests that circuits can have degenerate solutions, that is similar looking behavior with different underlying parameters across individuals. ...  Moreover, repeated performance of the same task is often associated with variable activity in the network generating this task [57∗∗].

 

Reference

Zhong, W., Barde, S., Mitsios, N., Adori, C., Oksvold, P., Feilitzen, K. V., ... & Hökfelt, T. (2022). The neuropeptide landscape of human prefrontal cortex. Proceedings of the National Academy of Sciences, 119(33), e2123146119. 



modified from Fig. 2 (Zhong et al., 2022). Expression levels of (A) Neuropeptides (NP) and (B) Neuropeptide Receptors (NPR) in human PFC. The color code indicates the type of genes (orange, precursor; green, NP; blue, NPR). Red arrows in A and B point to the transcripts studied with ISH (in situ hybridization).

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Sunday, July 31, 2022

Extracting reliable neurobiological biomarkers for complex subjective experiences isn't easy


"The self is the psychological counterpart of the default mode functionality of the brain." (Scalabrini et al., 2021).


The self studying how "The Self" is represented and constructed by the brain is apex meta-neuroscience.1 We can say that the self is a manifestation (or an illusory byproduct) of activity in the default mode network (medial prefrontal cortex, posterior cingulate cortex/precuneus, and angular gyrus), but what does this really mean? How do we relate specific neural states to aspects of a changeable self? In a field increasingly focused on remote control of genetically-defined microciruits, pinning down subjective internal phenomena seems presumptuous and hopelessly overambitious.

But of course, the inherent challenge of studying complex subjective experiences hasn't stopped scientists from trying. One active area of research involves characterizing the neural correlates of internal responses to traumatic events. This is of great clinical relevance, because the long-term persistence of fear, hypervigilance, negative affect, and intrusive memories after trauma can be disabling (post-traumatic stress disorder, PTSD). Alterations in one's sense of self (dissociation) can also occur in PTSD, and is the focus of the rest of this post. Dissociative symptoms can include:

  1. Depersonalization: Persistent or recurrent experiences of feeling detached from, and as if one were an outside observer of, one’s mental processes or body (e.g., feeling as though one were in a dream; feeling a sense of unreality of self or body or of time moving slowly).
     
  2. Derealization: Persistent or recurrent experiences of unreality of surroundings (e.g., the world around the individual is experienced as unreal, dreamlike, distant, or distorted). 


In states of depersonalization/derealization (which can occur independently of PTSD), one feels disconnected from the self and/or external reality. Dissociative symptoms are considered a maladaptive (but protective) response to stress and trauma. The standard method of eliciting dissociative symptoms during fMRI scanning is script-driven imagery (SDI), a highly unpleasant manipulation. Before the experiment, the participant recounts a narrative of the traumatic event, which is subsequently read back to them in the scanner. The presence of acute dissociative symptoms is determined by questionnaires and interviews before, during, and after the scan.

Early studies reported increased activity in prefrontal (and other) cortical regions in the SDI condition compared to baseline (Lanius et al., 2002) or a neutral script condition (Hopper et al., 2007), which was related to the severity of dissociative symptoms. This fits a theoretical perspective where higher cortical regions are tamping down limbic (and emotional) responses to the trauma induction. It should be mentioned that dissociative responses to SDI are generally less common than vivid re-experiencing of the trauma (30% vs. 70% in Lanius et al., 2002). Drawbacks of these studies include small samples sizes and inconsistencies in the fMRI results.

Mertens and colleagues (2022) set out to replicate these findings in a larger, more homogeneous population of 51 female survivors of childhood abuse. The study included additional questionnaires and separation of the SDI condition into “script listening” and “focused recall” phases (previous studies only included the latter). The experimental design included three runs of neutral script (30 sec each of listening/imaging and focused recall of the event) and three runs of trauma script, which was effective in increasing self-reported ratings of dissociative symptoms, e.g. “Did what you were experiencing seem unreal to you, like you were in a dream or watching a movie or play?” and “Did you feel like you were a spectator watching what was happening to you, like an observer or outsider?” (rated on a 0-6 scale).


click on image for a larger view
 

The fMRI results indicated that a wide swath of left cerebellum, occipital cortex, and supramarginal gyrus (parietal lobe) were more active in the trauma script than neutral condition, and this was specific to the script listening phase (no differences were observed during the focused recall phase). The same pattern was seen in the amygdala in a region of interest analysis. Importantly, there was no relationship between any of the clusters and any dissociation measure (amygdala and insula shown below).2



Fig. 2 (Mertens et al., 2022). Script-elicited signal activation clusters and corresponding brain-behaviour correlates (N = 51).


The authors tried a number of different analytic techniques to try and find a relationship between activation clusters and dissociative symptoms, but they could not. In their conclusions, they mentioned the significance of the replication crisis in neuroimaging and noted that “the current (null) findings highlight the difficulty of extracting reliable neurobiological biomarkers for complex subjective experiences such as dissociation.” Identifying who we are and what we experience via spatio-temporal patterns of brain activity are problems that do not have an imminent solution.


Footnotes

1 Self = a self-aware entity with fully-realized consciousness (whatever this means) 

2 Here, the number of self-report and clinician-rated measures was impressive, e.g. Dissociative Experiences scale (trait dissociation), Cambridge Depersonalization Scale, Clinician Administered Dissociative States Scale, Responses to Script-Driven Imagery, etc.

 

Further Reading

Feeling Mighty Unreal: Derealization in Kleine-Levin Syndrome

A Detached Sense of Self Associated with Altered Neural Responses to Mirror Touch

Role of the Vestibular System in the Construction of Self

Derealization / Dying

'I Do Not Exist' - Pathological Loss of Self after a Buddhist Retreat

The Stranger in the Mirror

Writing-Induced Fugue State


References

Hopper JW, Frewen PA, van der Kolk BA, Lanius RA. (2007). Neural correlates of reexperiencing, avoidance, and dissociation in PTSD: Symptom dimensions and emotion dysregulation in responses to script‐driven trauma imagery. Journal of Traumatic Stress 20(5):713-25.

Lanius RA, Williamson PC, Boksman K, Densmore M, Gupta M, Neufeld RW, Gati JS, Menon RS. (2002). Brain activation during script-driven imagery induced dissociative responses in PTSD: a functional magnetic resonance imaging investigation. Biological Psychiatry 52(4):305-11.

Lebois LA, Harnett NG, van Rooij SJ, Ely TD, Jovanovic T, Bruce SE, House SL, Ravichandran C, Dumornay NM, Finegold KE, Hill SB et al. (2022). Persistent dissociation and its neural correlates in predicting outcomes after trauma exposure. American Journal of Psychiatry Jun 22.

Mertens YL, Manthey A, Sierk A, Walter H, Daniels JK. (2022). Neural correlates of acute post-traumatic dissociation: a functional neuroimaging script-driven imagery study. BJPsych Open 8(4).

Northoff G, Scalabrini A. (2021). “Project for a Spatiotemporal Neuroscience”–Brain and Psyche Share Their Topography and Dynamic. Frontiers in Psychology 2021:4500.

Scalabrini A, Schimmenti A, De Amicis M, Porcelli P, Benedetti F, Mucci C, Northoff G. (2022). The self and its internal thought: In search for a psychological baseline. Consciousness and Cognition 97:103244.

 

Nested hierarchy of self in the brain

Fig. 4 (Northoff & Scalabrini, 2021). Nested hierarchy of self in the brain.


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