Thread by @PerezMGHLab

I think often about the TRANSLATION GAP - the ways that state-of-the-art brain science does not enter clinical discourse, practice, & education. MAJOR MISCONCEPTUALIZATIONS of Functional Neurological Disorder by PHYSICIANS point this out. #FND Brain Science: "The Basics". 1/20

Theme 1: MOTOR INHIBITION BY PREFRONTAL BRAIN AREAS - In an early study, Marshall et al. showed that attempted movements of the leg w functional weakness did not activate primary motor areas but led to anterior cingulate & orbitofrontal activity
DOI: 10.1016/s0010-0277(97)00020-6

Theme 1a: Vuilleumier et al. showed that preparing to move the limb with functional weakness led to increased prefrontal activity (i.e. ventromedial prefrontal cortex), suggesting THE INSTRUSION of prefrontal areas into movement.

10.1016/j.neuroimage.2009.05.023

Theme 2 in the #FND literature is altered (or biased) ATTENTION, as shown in part by abnormal engagement of cortical & subcortical brain areas implicated in attentional processes.

10.1093/brain/124.6.1077
10.1001/jama.2009.1834

A 3rd theme is abnormal (often increased) activity of deep brain structures (e.g., amygdala) involved in threat/fear processing & salience - as well as increased amygdala-motor control network coupling. @valvoon @MarkHallett007 et al. have shown this well.

10.1093/brain/awq054

INCREASED AMYGDALA-MOTOR CONTROL NETWORK COUPLING was replicated & expanded upon by @SelmaAybek @Tim_R_Nicholson @ProfTonyDavid & Kanaan - incl increased periaqueductal gray activity, another deep (subcortical) area.
10.1001/jamapsychiatry.2013.2842
10.1371/journal.pone.0123273

4th Theme DEFICIT IN ACTION AUTHORSHIP PERCEPTION. Relates to PREDICTION, the brain anticipates the sensory consequences of movement before they occur. Temporoparietal junction implicated @MarkHallett007 @valvoon Maurer et al
10.1212/WNL.0000000000002940
10.1017/S0033291717000071

5th Theme: sensing & interpreting of the state of the body - interoception. Some studies showed reduced accuracy in #FND, with INDIVIDUAL DIFFERENCES in heartbeat counting accuracy related to FND severity & insula / TPJ fiber tracts @Sojka4Petr
10.1111/epi.16532
10.1002/hbm.25304

The 6th theme, building upon themes 4 & 5, is that the science of PREDICTIVE PROCESSING, across sensorimotor and emotion domains, has been proposed to be IMPORTANT in the biology of #FND. Mark Edwards.

10.1093/brain/aws129
10.1016/j.neubiorev.2017.01.015
10.1093/brain/awac204

7th Theme: Reports that Insula & Anterior Cingulate functional coupling to the motor control network (& other areas involved in high-order calculations) - relate to symptom severity in "Dose-Dependent Fashion". @IbaiDiezPalacio

10.1136/jnnp-2011-300776
10.1136/jnnp-2018-319657

While there is still MUCH to do in the field - & many findings need replication & clarification - at least 4 brain networks appear to be implicated in #FND:
Sensorimotor
Salience
Default Mode
Ventral Attention

THEMES covered here relate to the brain mechanisms (pathophysiology concepts) outlined in the Drane et al article. @KhalsaLab @NegarFani

More to say about EMOTION PROCESSING, MOTOR CONTROL & SELF AGENCY - although these reviews cover that literature. @susannah_pick @Tim_R_Nicholson @jonstoneneuro @MarkHallett007
10.1136/jnnp-2018-319201
10.1016/j.nbd.2019.02.013
10.1016/S1474-4422(21)00422-1
10.1192/bjo.2022.597

Also - STRUCTURE & FUNCTION ARE VERY CLOSELY COUPLED IN THE BRAIN. Several recent reviews cover this topic for the interested reader:

10.1016/j.nicl.2019.101798
10.1016/j.neubiorev.2020.12.017

IMPORTANT: #FND is NOT Feigning - and studies including one led by @jonstoneneuro have shown activation differences between those with functional neurological disorder and feigning of symptoms.
10.1097/PSY.0b013e31815b6c14

Great work not summarized here, but highly substantive - including brain imaging research by @jungjoha @wesleytkerr @SamWeb29 @LennyMarapin & others worth checking out!
10.1016/j.seizure.2020.11.021
10.1016/j.yebeh.2022.108858
10.1016/j.nicl.2022.103090
10.1016/j.nicl.2020.102381

A rich set of multimodal studies at the intersection of functional seizures & TBI lead by Curt LaFrance & Jerzy Szaflarski et al., offer a deep dive into this important intersection.

10.1136/jnnp-2022-329838
10.1111/epi.17179
10.1111/epi.16758

#FND is a multi-network brain-based disorder directly at the intersection of #Neurology & #Psychiatry. This is a GENUINE neuropsychiatric disorder, one that offers important insights on the complexity of the human brain AND mind - w much more yet to learn!
sciencedirect.com/science/articl…

If you've not visited neurosymptoms.org & fndsociety.org, invaluable information on those websites. I hope that this effort, and that of many others here, will successfully COMBAT STIGMA & PROMOTE HEALING & RECOVERY.

@FNDHopeUK @FNDHope @AmandaFNDHope @FNDAction @FndPortal @FndRecovery @TomPlender @ConnectFnd @FndLifewith @NEAD_UK @tonesqueFND @FNDDimensions
@kylakenney21 @FND_stigmA @FND_Together & Many Others!