13:30 Uhr
Assoziation narzisstischer Persönlichkeitszüge mit MR-morphometrischen Parametern
L. Müller (Marburg, DE)
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Autor:innen:
L. Müller (Marburg, DE)
L. Schmidt (Marburg, DE)
I. Nenadic (Marburg, DE)
Narzissmus als Persönlichkeitskonstrukt zeichnet sich durch ausgeprägte Anspruchshaltung, Grandiosität und Verletzlichkeit aus. Zu den neurobiologischen Korrelaten dieser Traits, bei Gesunden oder Patient:innen mit narzisstischer Persönlichkeitsstörung, liegen einige wenige Assoziationsstudien zu hirnstrukturellen Parametern, vor allem in präfrontalen Arealen, vor. Diese weisen allerdings meist begrenzte Studienkohorten und heterogene Befunde auf. Wir testeten die Hypothese einer Korrelation subklinischer narzisstischer Züge mit dem Volumen der grauen Substanz und der Oberfläche des Cortex in einer größeren Studienkohorte gesunder Proband:innen.
Wir analysierten strukturelle T1-MRT-Daten von N=382 Proband:innen mittels voxel-basierter Morphometrie (CAT12) bezüglich einer Korrelation mit der NPI-Gesamtskala (Narcissistic Personality Inventory) und drei Subskalen nach Ackermann et al.: Leadership/Authority (LA), Grandiosity/Exhibitionism (GE) sowie Eploitative/Entitlement (EE). Hierbei wurde das threshold-free cluster enhancement angewandt, sowie innerhalb der allgemeinen linearen Modelle je eine Korrektur für multiple Vergleiche mittels FWE-Korrektur.
Während wir keine Assoziationen der genannten Skalen mit den Maßen der corticalen Oberfläche und Dicke fanden, zeigte sich eine signifikante positive Korrelation der NPI-Unterskala GE mit dem Volumen der grauen Substanz im linken Gyrus temporalis medius sowie eine signifikante positive Korrelation der NPI-Unterskala EE mit dem Volumen der grauen Substanz im linken Gyrus frontalis superior und dem rechten orbitofrontalen Cortex.
Unsere Befunde stützen die Annahme einer subskalenabhängigen Assoziation mit präfrontalen Arealen und weisen zukünftige neurobiologische Betrachtungen verstärkt auf die Ebene unterschiedlicher Teilfacetten des Narzissmus. Neben Weiterentwicklungen der psychometrischen Validität angewandter Subskalen sind weitere Replikationen in Kohorten mit breiterer Spannweite narzisstischer Traits bedeutsam.
13:42 Uhr
Subklinischer vulnerabler Narzissmus und dessen Assoziation zu fronto-limbischen Faserzügen
L. Schmidt (Marburg, DE)
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Autor:innen:
L. Schmidt (Marburg, DE)
I. Nenadic (DE)
Das diametrale Konstrukt Narzissmus enthält einerseits grandiose Anteile, die mit gesteigertem Selbstwert, Empathiemangel und Größenphanatsien verbunden sind. Narzisstische Verletzlichkeit hingegen ist assoziiert mit emotionaler Vulnerabilität und psychischen Achse-I und II-Störungen. Bei narzisstischer Persönlichkeitsstörung konnten bereits präfrontale und insulare strukturelle Veränderungen gezeigt werden, sowie subklinisch im präfrontalen Cortex.
Wir testeten die Hypothese, dass bereits subklinischer Narzissmus mit der Integrität der weißen Substanz in Faserzügen, welche die strukturelle Konnektivität des präfrontalen Cortex mit anderen Arealen prägen und Grundlage für kognitive und emotionale Evaluation sind (Cingulum, anteriorer Thalamusstiel, Fasciculus uncinatus) assoziiert ist. Bei n= 267 Versuchspersonen untersuchten wir mittels DTI (diffusion tensor imaging) und tract-based spacial statistics (TBSS) die fraktionelle Anisotropie (FA), als Indikator für Faserintegrität und korrelierten FA zu Werten des Pathological narcissism inventory (PNI).
Wir fanden eine positive Korrelation zwischen PNI Gesamtscore und FA im rechten posterioren Cingulum. Die PNI Skala "Vulnerabilität" war positive korreliert mit der FA des linken anterioren und rechten posterioren Cingulum . Es zeigten sich keine Assoziationen der PNI-Skala „Grandiosität“ mit FA.
Diese Arbeit zeigt erstmalig in einer großen subklinischen Stichprobe Assoziationen der weißen Substanz in fronto-limbischen Faserzügen. Unsere Ergebnisse weisen auf einen Zusammenhang v.a. zu vulnerablen narzisstischen Merkmalen und genannten Hirnstrukturen hin, die u.a. für Emotionsregulation und Verhaltenskontrolle relevant sind. Zusätzliche Analysen geben Hinweise darauf, dass es außerdem eine relevante Interaktion des Geschlechtes und Narzissmusausprägung in Bezug zu diesen Strukturen für einige Subskalen des PNI gibt.
13:54 Uhr
Neural signature and symptom correlations of model-free and model-based decision making in obsessive-compulsive disorder
P. Sen (München, DE)
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Autor:innen:
P. Sen (München, DE)
K. Koch (DE)
F. Knolle (DE)
Decision making is considered to be based on two competing parallel systems of habitual model-free (MF) learning and goal-directed model-based (MB) learning. While healthy individuals show parallel engagement in both MF and MB decision making processes, Obsessive Compulsive Disorder (OCD) patients are biased towards a more MF pattern. This tendency may promote obsessive and compulsive decision behaviors which in turn may relate to clinical symptoms. However, the underlying neural signatures are still unclear.
As computational modelling has been integrated into the analysis of imaging data to identify dysfunctional mechanisms, we combined hierarchical Bayesian modelling with fMRI to investigate potentially altered decision making patterns in OCD patients (n = 22) compared to healthy controls (n = 22). Here, we used the two-step Markov decision making task to investigate MB and MF decision making behaviors based on four model parameters: model-weights representing MF vs. MB decisions, learning rate, inverse temperature representing choice randomness, and perseverance.
We observed higher choice randomness in patients compared to healthy controls. While the behavioral results suggested a MF decision making pattern in both groups, the model-weights parameter indicated that controls chose a more MF approach, whereas patients used a mixed approach. The learning rate inversely correlated with MF reward prediction error signals in the nucleus accumbens, a key region for MF processing. Activations were also present in the dorsal and ventral striatum. However, these associations were not observed with unsigned prediction errors.
To our knowledge, this is the first study exploring decision making in OCD patients with the two-step task using computational modelling in combination with fMRI. Our results show that this multidimensional approach has great potential to identify underlying neural mechanisms of OCD, and hence, aid in developing targeted treatments and interventions.
14:06 Uhr
Neural correlates of memory and imagination
C. McCormick (Bonn, DE)
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Autor:in:
C. McCormick (Bonn, DE)
If we close our eyes, most of us can vividly imagine events from our past or envision never-experienced scenarios set in the future. This type of mental imagery is supported by a key set of brain regions, including the hippocampus, ventromedial prefrontal cortex and visual-perceptual cortices. My research focusses on each region’s precise contribution and about their dynamic interactions. Uncovering the neuronal basis of mental imagery offers crucial insights into experiential cognitive functions such as autobiographical memory, future thinking, and navigation, but is also important, for decision-making, emotion regulation and mind-wandering.
In this talk, I will present hippocampal subfield contributions to autobiographical memory from structural and functional magnetic resonance imaging 7 Tesla fMRI. Furthermore, I present studies examining people who complain about their memory and imagination (i.e., due to Aphantasia, limbic encephalitis and various forms of neurodegenerative dementia).
My research is important to a broad field of psychiatry and psychotherapy since many patients with psychiatric disorders also complain about difficulties in memory and imagination. Furthermore, my research urges towards more awareness of a broad spectrum of mnemonic and imaginative abilities in psychiatric patients.
14:18 Uhr
Neuronal compensation in subjective cognitive decline
C. Krebs (Bern, CH)
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Autor:innen:
C. Krebs (Bern, CH)
E. Brill (Bern, CH)
M. Züst (Bern, CH)
A. Brem (Bern, CH)
S. Klöppel (Bern, CH)
Many older adults are affected from a subjective decline in cognitive performance. While the causes for this subjective feeling are manifold, it sometimes is a preclinical stage of dementia.
There is evidence that in early neurodegeneration brain functions can counteract beginning neuropathologies through increased activity, resulting in stable task performance. This process is called neuronal compensation. But it seems that this compensatory process is only possible for some time until neurodegeneration has proceeded too far and compensation is no longer possible. While there are many studies investigating memory functions in different populations with and without neurodegeneration, little is known about compensation in other cognitive domains than memory. Additionally, there is no uniform definition of subjective cognitive decline, leading to heterogeneous findings in neuroimaging studies. We investigated a sample including 55 participants with subjective cognitive decline in fMRI tasks for associative memory and spatial abilities. According to our definition, increased brain activity associated with high task performance and a high level of hippocampal atrophy would indicate successful compensation. Our results did not reveal significant compensatory brain activity in any of the two tasks. We repeated the analysis in a subsample (n = 25) where blood-based biomarkers indicated amyloid positivity which increased the probability to include only participants were subjective cognitive decline was a preclinical stage of Alzheimer’s disease. Also in this subsample no compensatory brain activity was found. It is possible that compensatory brain activity is not present in an early disease-stage or our sample has been to heterogeneous to detect subtle processes like neuronal compensation.
14:30 Uhr
Preserved inhibitory temporo-parietal effective connectivity is associated with explicit memory performance in older adults
B. Schott (Göttingen, DE)
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Autor:innen:
B. Schott (Göttingen, DE)
J. Soch (Göttingen, DE)
J. Kizilirmak (Göttingen, DE)
H. Schütze (Magdeburg, DE)
A. Assmann (Magdeburg, DE)
A. Richter (Magdeburg, DE)
Background: Successful encoding of novel information into episodic traces is associated with increased activation of the hippocampus and temporo-occipital cortical structures like the parahippocampal place area (PPA). On the other hand, midline brain structures like the precuneus, which is prominently involved in memory retrieval, typically show encoding-related deactivations. Previous studies show that older adults exhibit both lower episodic memory performance and reduced precuneus deactivations. However, it is still unclear how the hippocampus interacts with temporo-occipital and medial parietal structures to facilitate successful memory formation and whether these interactions are affected by aging.
Methods: Here, we used dynamic causal modeling (DCM) of functional magnetic resonance imaging (fMRI) data from three different cohorts to elucidate the information flow between the hippocampus, the PPA and the precuneus during episodic memory formation for visual scene stimuli. We then tested the relationship between effective connectivity of the memory network using support vector regression and robust correlations.
Results: In 117 young, healthy adults, we observed pronounced excitatory effective connectivity from the PPA to the hippocampus and inhibitory connections from the PPA to the precuneus. Both were further up-regulated during successful encoding. This pattern could be replicated in two cohorts of young and older adults (N = 58 young, 83 older; 64 young, 84 older). Older adults exhibited attenuated negative PPA-precuneus connectivity, which correlated negatively with memory performance.
Discussion/Conclusion: Our results provide insight into the network dynamics underlying encoding-related activations and deactivations and suggest that age-related differences in memory-related network activity manifest in altered temporo-parietal neocortical rather than hippocampal connectivity.