Poster B78, Tuesday, August 20, 2019, 3:15 – 5:00 pm, Restaurant Hall
Patterns of structural covariation with left precentral gyrus predict words in noise performance
Alexis Hervais-Adelman1, Robert Becker1;1Neurolinguistics, Department of Psychology, University of Zurich
Structural covariation of the brain refers to the fact that across a population some brain areas show correlated inter-individual differences. Patterns of structural covariation have been assessed using a technique named MACACC (“Mapping anatomical correlations across cerebral cortex”) and have been shown to reflect brain connectivity. Furthermore they have been revealed to be consistently different between groups with differing IQ. The technique therefore provides a method to generate insights into inter-areal relationships that might be related to individual performance differences. Here we apply it to the neural bases of speech in noise perception. We choose to examine left precentral gyrus as it is a region whose implication in speech comprehension remains controversial although there is compelling evidence that it may be implicated in phonological processing and degraded speech perception. We investigated structural covariation in a large sample (N=1110) of individuals, for whom structural brain imaging had been carried out as part of the Human Connectome Project (HCP). These individuals underwent evaluation of their word in noise recognition ability, using the words in noise test (WIN). The WIN requires individuals to listen to monosyllabic words embedded in multitalker babble. Participants repeat words, and the SNR is decreased stepwise until no more targets can be correctly reported. Participants were divided into three groups of N=370 based upon their performance, designated as High, Mid and Low. In order to ensure that effects were specific to WIN, we deconfounded scores for the possible influence of a large number of other behavioural and demographic variables made available as part of the HCP. Structural data were preprocessed as per the standard protocol of the HCP. Cortical thickness values were used for a set of 68 parcels based on the Desikan-Killiany atlas. In order to determine whether structural covariance is related to WIN scores, we tested whether the slope of the relationship between thickness of left precentral gyrus and the other 67 parcels was significantly different as a function of group. This was achieved by testing the interaction between group and target thickness in a linear model. Significant interactions were found for a number of targets, principal among which (in terms of statistical significance) were: right cuneus (F(1,1106)=9.05, p=.003), left pars triangularis (F(1,1106)=7.30, p=.007) and the left entorhinal cortex (F(1,1106)=6.55, p=0.011). The nature of the covariation pattern in these regions differed as a function of WIN performance group, such that there was an increase in slope of the relationship between left precentral gyrus and the right cuneus with performance, while the inverse relationship was apparent between the seed and both left entorhinal cortex and left pars triangularis. We acknowledge that these results are derived from a crude parcellation scheme, and that they target only one relatively controversial component of the speech comprehension system. Nonetheless, applying the MACACC method reveals some structure in the cortical relationships that might related to speech in noise comprehension. Thus, evaluating covariation patterns derived from structural measures may provide intriguing and worthwhile insights into inter-areal cortical relationships that contribute to behaviour.
Themes: Speech Perception, Speech Motor Control
Method: Other