Age-related Changes in White Matter Tracts Associated with Face Recognition System

Resumen

Objectives. Analyze anatomical connectivity and integrity of three white matter tracts involve in face recognition system in three age samples: children, young adults and elderly adults. Background. The neural circuit of face recognition has been well characterized in a wide age spectrum. However, anatomical connectivity changes across aging are still unclear. Methods. The variations in the connectivity of this circuit in three age samples (32 individuals, 8 to 78 years) are examined here, by focusing in three major association tracts: inferior frontal-occipital (IFOF), inferior longitudinal (ILF) and superior longitudinal fasciculi (SLF). These seem to be connectors between nodes of the face recognition system (occipital face area (OFA), face fusiform area (FFA) and superior temporal sulcus (STS), although little is known about SLF. Fiber tracking computations were performed using a deterministic method. Results. Fractional anisotropy (FA) and number of streamlines of the IFOF, ILF and SLF were estimated. Resulting FA values are similar across groups in ILF and SLF. However, the IFOF shows a decrease FA in elderly adults. In addition, children exhibit lower number of streamlines than young adults in all tracts, while elderly exhibit a selective decrease in the bilateral IFOF and a selective increase in SLF. Conclusions. Our study shows that the anatomical connectivity of the face recognition circuit remains similar. Aging produces a selective decrease in the occipito-frontal connectivity, preserving the connectivity with the temporal lobe.