Histological basis of laminar MRI patterns in high resolution images of fixed human auditory cortex

Functional magnetic resonance imaging (fMRI) studies of the auditory region of the temporal lobe would benefit from the availability of image contrast that allowed direct identification of the primary auditory cortex, as this region cannot be accurately located using gyral landmarks alone. Previous work has suggested that the primary area can be identified in magnetic resonance (MR) images because of its relatively high myelin content. However, MR images are also affected by the iron content of the tissue and in this study we sought to confirm that different MR image contrasts did correlate with the myelin content in the grey matter and were not primarily affected by iron content as is the case in the primary visual and somatosensory areas. By imaging blocks of fixed post-mortem cortex in a 7 Tesla scanner and then sectioning them for histological staining we sought to assess the relative contribution of myelin and iron to the grey matter contrast in the auditory region. Evaluating the image contrast in T2*-weighted images and quantitative R2* maps showed a reasonably high correlation between the myelin density of the grey matter and the intensity of the MR images. The correlation with T1-weighted phase sensitive inversion recovery (PSIR) images was better than with the previous two image types, and there were clearly differentiated borders between adjacent cortical areas in these images. A significant amount of iron was present in the auditory region, but did not seem to contribute to the laminar pattern of the cortical grey matter in MR images. Similar levels of iron were present in the grey and white matter and although iron was present in fibres within the grey matter, these fibres were fairly uniformly distributed across the cortex. Thus we conclude that T1- and T2*-weighted imaging sequences do demonstrate the relatively high myelin levels that are characteristic of the deep layers in primary auditory cortex and allow it and some of the surrounding areas to be reliably distinguished

Modelling human choices: MADeM and decision‑making

Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)

26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15–20 July 2017

This work was produced as part of the activities of FAPESP Research,\ud Disseminations and Innovation Center for Neuromathematics (grant\ud 2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud supported by a CNPq fellowship (grant 306251/2014-0)

Static versus dynamic medical images : the role of cue utilization in diagnostic performance

Echocardiographers can detect abnormalities accurately and rapidly from dynamic images. This is likely due to the application of cue-based associations resident in memory, a process known as cue utilization. This study investigated whether cue utilization is associated with the ability to apply within-domain capabilities (dynamic) to more degraded images (static). Fifty-eight echocardiographers completed the echocardiography edition of the Expert Intensive Skills Evaluation 2.0 (EXPERTise 2.0) to establish behavioral indicators of within-domain cue utilization. They also completed an abnormality detection and categorization task that comprised briefly presented static and moving images (50% abnormal). Behaviors consistent with higher cue utilization were associated with greater accuracy in detecting both static and dynamic images but not for categorization. This study provides important information about how experts who have the capacity to utilize cue-based strategies can rapidly and accurately detect abnormalities from domain-specific stimuli and generalize their skills to more challenging stimuli