title: Inter-individual variation in fronto-temporal connectivity predicts the ability to learn different types of associations.
abstract: The uncinate fasciculus connects portions of the anterior and medial temporal lobes to the lateral orbitofrontal cortex, so it has long been thought that this limbic fiber pathway plays an important role in episodic memory. Some types of episodic memory are impaired after damage to the uncinate, while others remain intact. Because of this, the specific role played by the uncinate fasciculus in episodic memory remains undetermined. In the present study, we tested the hypothesis that the uncinate fasciculus is involved in episodic memory tasks that have high competition between representations at retrieval. To test this hypothesis, healthy young adults performed three tasks: Experiment 1 in which they learned to associate names with faces through feedback provided at the end of each trial; Experiment 2 in which they learned to associate fractals with cued locations through feedback provided at the end of each trial; and Experiment 3 in which unique faces were remembered in a paradigm with low retrieval competition. Diffusion tensor imaging and deterministic tractography methods were used to extract measures of uncinate fasciculus microstructure. Results revealed that microstructural properties of the uncinate, but not a control tract, the inferior longitudinal fasciculus, significantly predicted individual differences in performance on the face-name and fractal-location tasks. However, no relationship was observed for simple face memory (Experiment 3). These findings suggest that the uncinate fasciculus may be important for adjudicating between competing memory representations at the time of episodic retrieval.
authors.affiliation: Temple University, Department of Psychology, United States.
authors.forename: Kylie H
authors.initials: KH
authors.lastname: Alm
authors.affiliation: Temple University, Department of Psychology, United States.
authors.forename: Tyler
authors.initials: T
authors.lastname: Rolheiser
authors.affiliation: Temple University, Department of Psychology, United States. Electronic address: iolson@temple.edu.
authors.forename: Ingrid R
authors.initials: IR
authors.lastname: Olson
mesh_terms: D000293:Adolescent; D000328:Adult; D001245:Association Learning; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology* / Q000502:physiology; D006801:Humans; D007206:Individuality; D008297:Male; D061212:Memory, Episodic; D011939:Mental Recall; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D013702:Temporal Lobe / Q000033:anatomy & histology* / Q000502:physiology; D066127:White Matter / Q000033:anatomy & histology; D055815:Young Adult
keywords: Associative memory; Diffusion imaging; Faces; Limbic; Orbitofrontal cortex; Proper names; Temporal pole; Uncinate fasciculus; White matter