Neurocognitive predictors of food memory in healthy adults - A preregistered analysis

Memory processes have long been known to determine food choices (Rozin & Zellner, 1985) but recognition memory of food and its cognitive, homeostatic and neuroanatomical predictors are still largely understudied. 60 healthy, overweight, non-restrictive eating adults (20 females) took part in a food wanting and subsequent food recognition and lure discrimination task at four time points after a standardized breakfast shake. With advanced tractography of 3 T diffusion-weighted imaging data, we investigated the influence of the uncinate fasciculus' (UF) brain microstructure on the interplay of food wanting and memory processes. The analysis was preregistered in detail and conducted with Bayesian multilevel regression modeling. Target recognition (d') and lure discrimination (LDI) performance of food tended to be higher than of art images while single image food memory accuracy evidently dominated art memory. On this single item level, wanting enhanced recognition accuracy and caloric content enhanced food memory accuracy. The enhancement by reward anticipation was most pronounced during memory encoding. Subjective hunger level did not predict performance on the memory task. The microstructure of the UF did neither evidently affect memory performance outcomes nor moderate the wanting enhancement of the recognition accuracy. Interestingly, female participants outperformed males on the memory task, and individuals with stronger neuroticism showed poorer memory performance. We shed light on to date understudied processes in food decision-making: reward anticipation influenced recognition accuracy and food memory was enhanced by higher caloric content, both effects might shape food decisions. Our findings indicate that brain microstructure does not affect food decision processes in adult populations with overweight. We suggest extending investigation of this interplay to brain activity as well as to populations with eating behaviour disorders.

Orbitofrontal extensions of the insular glioma based on subdivision of the uncinate fasciculus

The insular gliomas were classified based on their locations and extensions to the adjacent areas. The insular and orbitofrontal cortices with underlying fiber tracts were studied on ten (20 sides) human cadaveric brains and two heads. Twenty patients with insular gliomas with the orbitofrontal or septal region extensions were studied on preoperative magnetic resonance imaging (MRI). Insular gliomas can extend to the orbitofrontal area dorsolaterally and/or ventromedially through the subdivision of the uncinate fasciculus. The dorsolateral part of the uncinate fasciculus interconnects the temporopolar area to the lateral orbitofrontal cortex through insula, and the ventromedial part of the uncinate fasciculus interconnects the temporopolar area to the medial orbital cortex, gyrus rectus, and septal region. The gyrus rectus infiltration on MRI indicates a ventromedial involvement by passing through the ventromedial part of the uncinate fasciculus. Diffusion tensor imaging (DTI) MRI demonstration of the UF is difficult due to the interruption of the fiber tracts by tumor. Tumor infiltration extending to the gyrus rectus requires a 15° lateral tilting with vertex toward contralateral side, as well as 70° head rotation to the contralateral side of lesion, for exposure of frontal base, septal region, and lateral border of the anterior perforating substance at the same time with the exposure of whole sylvian fissure via transsylvian approach of the insular tumors. An understanding of the orbitofrontal extension of the insular tumor based on the subdivisions of UF is useful in preoperative surgical planning and can assist for gross total resection.

Structural connections support emotional connections: Uncinate Fasciculus microstructure is related to the ability to decode facial emotion expressions

The Uncinate Fasciculus (UF) is an association fibre tract connecting regions in the frontal and anterior temporal lobes. UF disruption is seen in several disorders associated with impaired social behaviour, but its functional role is unclear. Here we set out to test the hypothesis that the UF is important for facial expression processing, an ability fundamental to adaptive social behaviour. In two separate experiments in healthy adults, we used high-angular resolution diffusion-weighted imaging (HARDI) and constrained spherical deconvolution (CSD) tractography to virtually dissect the UF, plus a control tract (the corticospinal tract (CST)), and quantify, via fractional anisotropy (FA), individual differences in tract microstructure. In Experiment 1, participants completed the Reading the Mind in the Eyes Task (RMET), a well-validated assay of facial expression decoding. In Experiment 2, a different set of participants completed the RMET, plus an odd-emotion-out task of facial emotion discrimination. In both experiments, participants also completed a control odd-identity-out facial identity discrimination task. In Experiment 1, FA of the right-, but not the left-hemisphere, UF was significantly correlated with performance on the RMET task, specifically for emotional, but not neutral expressions. UF FA was not significantly correlated with facial identity discrimination performance. In Experiment 2, FA of the right-, but not left-hemisphere, UF was again significantly correlated with performance on emotional items from the RMET, together with performance on the facial emotion discrimination task. Again, no significant association was found between UF FA and facial identity discrimination performance. Our findings highlight the contribution of right-hemisphere UF microstructure to inter-individual variability in the ability to decode facial emotion expressions, and may explain why disruption of this pathway affects social behaviour.

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We studied white matter microstructure correlates of facial emotion decoding skills.

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Focused on the role of a key limbic tract, the Uncinate Fasciculus (UF).

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Right UF microstructure linked to facial expression decoding skills.

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UF microstructure not related to facial identity discrimination skills.

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Right UF has a distinct role in the processing of facial expressions of emotion.