Outline 4.1 Global Connectivity Patterns
- Global erklären
- SLF nutzen?
- 44 vs 45 nochmal drüberlesen
To-Do’s
- 44 eher auf FEF seite packen
- FEF Teil ist viel zu groß und IFJ part viel zu kurz
- neue Plots generieren mit besseren Visuals
- den Teil mit HCP language task rausnehmen
- [ ]
4.1 Global Connectivity Patterns
Before examining each stream individually, we assess the overall functional dissociation between the auditory ‘what’ and ‘where’ streams. Using full and partial correlation, we compare the connectivity profiles of the two prefrontal seed regions FEF and IFJa, and validate their anatomical specificity against neighboring control seeds.
4.1.1 FEF vs. IFJa: Validation of Prefrontal Seed Regions
To validate the anatomical specificity of our seed regions, we compared their partial correlation connectivity fingerprints across both hemispheres (Figure FEF vs IFJa full connectivity.png).
The functional connectivity analysis with full correlation reveals a clear double dissociation (Figure: FEF vs IFJa full corr.png) with FEF significantly coupling with spatial-parietal areas ((full corr.: OP4 , 7Am , 7PC , RH)) with exceptions of FEF coupling with TA2 (full corr.: , RH) stronger than IFJa and TA2 and 55b connecting stronger to IFJa than to FEF.
Then we applied partial correlation to partial out third party connectors to see a clear picture of the connectivity patterns within the auditory streams. The partial correlation analysis reveals that the most direct auditory connections to FEF are consistently rooted in the spatial orienting network. Both hemispheres show strong coupling with the inferior parietal cluster (PF, PFop, PFcm). However, the network shows a distinct right-hemispheric dominance in specific regions, consistent with widely accepted right-lateralization framework for spatial auditory processing (Hickok & Poeppel, 2007). While the left hemisphere dominates in FOP3 (), 7Am () and 7PC (), the right hemisphere demonstrates a clear dominance in PF ( vs. left ) and shows partial correlation with the perisylvian language area (PSL, ), suggesting a stronger specialized right-lateralized fronto-parietal integration for spatial auditory processing (Hickok & Poeppel 2007 - Nature).
Figure: Functional Connectivity: Left vs right hemisphere, full correlation
Data: 0 DATA for Bachelorarbeit
Figure: Functional Connectivity: left vs right hemisphere, part correlation
Data: 0 DATA for Bachelorarbeit
- FEF: The FEF seed exhibits robust full correlation with the superior parietal lobe (7AL, 7Am, 7PC). This replicates the where-stream, similar to the visual stream Bedini & Baldauf (2021), together with auditory and motor regions such as A5, PBelt, FOP1, STV and PSL
- IFJa: In contrast, the IFJa showed strong coupling with the anterior language network (HCP language task)
4.1.2 Topographical Validation: IFJp Control Seed
To validate the top-down control over the auditory what-stream is driven by the anterior subdivision of IFJ, a control partial correlation model substituted IFJa for IFJp, its immediate neighbor.
The control analysis confirms the functional dissociation of where and what stream. The FEF maintains its robust connectivity to the dorsal auditory and motor network with 23 significant regions in the left and 20 in the right hemisphere.
In the profound contrast substituting the what-hub with IFJp leads to a significant drop in the connectivity pattern of the semantic what-stream. The IFJp fails to communicate with the temporal lobe in comparison to the FEF.
This contrast provides the evidence that the prefrontal control hub over auditory identity processing is functionally exclusively anchored in the IFJa.
FEF vs. IFJp right hemisphere: part corr
FEF vs IFJp part left hemisphere:
Notes & Scrapbook
Hier Dinge abladen, die noch keinen Platz im Text haben, damit der Schreibfluss nicht stoppt.
see also
4.0 Results
4.2 Testing the “Where” Stream (FEF Connectivity)
4.3 Testing the “What” Stream (IFJa Connectivity)
4.4 Resolving Ambiguities