Outline 3.2 Selection of ROIs
- Prefrontal Seed Regions
- FEF
- 55b
- IFJa (vs IFJp)
- 44, 45, 47l
- FEF
- Where Stream
- A5
- MST/MT
- 7AL
- FOP1
ToDo’s
- checken, ob ich wirklich distiction zwischen IFJa und IFJp erklären soll
Outline 3.2 Selection of ROIs
- Prefrontal Seed Regions
- FEF
- IFJa (Target Seed)
- IFJp (Control Seed)
- Auditory What-Stream Target Regions
- Core/Belt (PBelt)
- Semantic (STGa, STSda, STSdp, TA2, TPOJ1)
- Association (TPOJ2, TPOJ3)
- Auditory Where-Stream Target Regions
- Dorsal/Spatial (A5, 7AL, 7Am, 7PC)
- Opercular (FOP1)
- Ambiguous/Control (MT/MST, PSL)
ToDo’s
- checken: Reicht die Begründung für den Transfer der IFJa/p-Distinktion (visuell → auditorisch) aus?
- checken: Paper für das Fehlen auditorischer Reaktionen in MT/MST endgültig verlinken (Siehe Source).
- kürzen: 3.2 Selection of Regions of Interest (ROIs) hier habe ich zu viel discussion points, die müssen in discussion rein und hier raus!
REVIEW
3.2 Selection of Regions of Interest (ROIs)
To test the hypothesis of supramodal prefrontal control over auditory processing, a comprehensive set of 36 target ROIs and 2 primary seed regions (plus one control seed) per hemisphere was defined. All regions were identified utilizing the multimodal cortical parcellation (HCP-MMP1.0) by Glasser et al. (2016) - Nature. This atlas provides superior neuroanatomical precision by integrating structural, functional, and connectivity data.
The selected ROIs are categorized into functional networks reflecting the auditory dual-stream architecture and their respective prefrontal controllers. The large sample size (N=812) provides sufficient statistical power to detect moderate connectivity effects across all ROI pairs after multiple comparison correction
3.2.1 The HCP-MMP1 Atlas
Before defining specific regions, the choice of the underlying atlas must be justified. Unlike traditional parcellations based solely on cytoarchitecture (e.g., Brodmann areas), the HCP-MMP1.0 atlas integrates four distinct modalities:
- Cortical Myelin Content: Identified via T1w/T2w ratios.
- Cortical Thickness: Measuring structural differences.
- Task-fMRI Activation: Pinpointing functional hubs.
- Resting-State Functional Connectivity: Mapping intrinsic networks.
This multimodal approach is essential for this study because it allows for the differentiation of functionally distinct areas that appear homogenous in classical maps. For instance, it enables the isolation of the IFJa from the surrounding prefrontal cortex, which is important for the auditory dual-stream architecture.
3.2.2 Prefrontal Seed Regions (The Conductors)
We selected distinct prefrontal control hubs based on the functional dissociation previously established in the visual system by Bedini & Baldauf (2021). This selection tests whether these visual control architectures map onto auditory processing.
- Frontal Eye Field (FEF): A core node of the Dorsal Attention Network (DAN), hypothesized to exert top-down control over the spatial auditory “Where”-stream.
- Anterior Inferior Frontal Junction (IFJa): Part of the Frontoparietal Network (FPN), hypothesized to mediate feature-based attention and semantic processing within the auditory “What”-stream Bedini & Baldauf (2021).
- Posterior Inferior Frontal Junction (IFJp) - Control Seed: Included strictly as a methodological baseline. IFJp is associated with the Multiple-Demand (MD) system for general-purpose executive tasks Bedini & Baldauf (2021). Factoring out its variance allows for a double dissociation, ensuring that the observed control over the auditory network is highly specific to the IFJa.
3.2.3 The Dorsal Pathways (Where & How)
The dorsal pathways process spatial localization (Where) and sensorimotor integration (How) (Hickok & Poeppel 2007 - Nature). ROI selection relies on the connectivity profiles outlined by Rolls et al. (2023) - Cerebral Cortex and recent functional data by Dureux (2024).
3.2.3.1 The Spatial-Orienting Network (Where-Stream)
This network tracks moving auditory objects and directs spatial focus.
- 7AL, 7Am, 7PC: Superior parietal areas receiving direct input from early auditory regions, crucial for auditory spatial attention and motion tracking Rolls et al. (2023) - Cerebral Cortex.
- PF, PFop: These areas correspond to the Inferior Perietal Lobule (Baker (2018)) and according to Rauschecker & Scott (2009) - Nature Neuroscience the IPL plays an important role in the dorsal auditory pathway (Glasser et al. (2016) - Nature)
- PFcm: Defined by Glasser et al. (2016) - Nature as a heavily myelinated inferior parietal region with strong somatosensory properties along with OP1-4 and FOP1. Although recent evidence indicates a lack of direct auditory responsiveness (Dureux et al., 2024), it was strategically included due to its anatomical position bridging the auditory-motor interface (OP4) and multimodal integration hubs (PSL).
- MT, MST: Classical supramodal motion hubs. They receive effective connectivity from auditory areas (A4/A5) to enable the tracking of auditory movement in space Rolls et al. (2023) - Cerebral Cortex.
3.2.3.2 The Motor Interface (How-Stream)
This interface translates auditory representations into articulatory motor plans (Sound-to-Motor mapping, Hickok & Poeppel (2004) - Cognition, Hickok & Poeppel 2007 - Nature)
- 55b: A premotor hub exhibiting responses to vocal stimuli being assigned to a language area. Interesting because 55b is a neighbor of the prefrontal seed region FEF and Glasser et al. (2016) - Nature; Dureux (2024).
- 44 (Broca’s pars opercularis): According to Rolls et al. (2023) - Cerebral Cortex Area 44 might be forming a dorsal auditory pathway with PBelt, A4, A5 and motion areas MT and MST.
- OP4, FOP1, FOP2, FOP3, 43: According to Frühholz the frontal operculum is connected to posterior STG and anterior IFG via dorsal pathways Frühholz (2015) - NeuroImage. OP4 specifically demonstrates exclusive sensitivity to human vocalizations Dureux (2024). Area 43 was included due to its anatomical position between the FOP and premotor cortex, potentially serving as an interface along the auditory-motor-pathway.
- SCEF (Supplementary and Cingulate Eye Field): A medial frontal cingulate area anatomically adjacent to the FEF. Despite responding almost exclusively to vocalizations (Dureux (2024)), its medial frontal anatomy and oculomotor system affiliation place it within the dorsal network. Dureux (2024) further groups SCEF functionally with premotor area 55b, OP4, and Broca’s areas 44 and 45 in the same vocalization-selective cluster.
3.2.4 The Ventral Pathways (What)
The ventral stream decodes auditory object identity, semantics, and speech perception.
3.2.3.1 Ventral Semantic and Identity Network
- STGa, STSda, STSdp, STSva, STSvp, TA2: The semantic core of the ventral pathway processing complex auditory objects. The STS complex integrates vocal inputs with facial motor representations to decode identity and message (Glasser et al. (2016) - Nature, Rolls (2022) - NeuroImage, Rolls et al. (2023) - Cerebral Cortex)
- AVI: The Anterior Ventral Insula shows activations to auditory stimuli alongside inferior frontal regions 55b, IFJp, IFJa, IFSp, 44, 45, and OP4. AVI exhibits highly specific capabilities in distinguishing vocalizations from noise, extending the semantic network into insular evaluation regions Dureux (2024).
- 45, 47l, IFSp: The frontal termini of the ventral meaning pathway. Area 45 (Broca’s pars triangularis) and 47l handle semantic selection, while IFSp shows responses to vocalization along with 44, 45, IFJp, OP4 and 55b ; Rolls et al. (2023) - Cerebral Cortex, Dureux (2024)
3.2.4.2 Anterior Temporal Semantic Regions
- TE1a, TGd, TGv (Temporal Pole): Following the effective connectivity analysis of Rolls (2022) - NeuroImage, these areas represent the semantic integration hubs of the temporal lobe. We intentionally differentiated between these regions to test the specificity of prefrontal control:
- TE1a & TGd (Group 1): Associated with an inferior, visual-semantic system. Their lack of effective connectivity with the IFJa makes them ideal candidates to evaluate the boundaries of the IFJa-controlled auditory network.
- TGv (Group 2): Integrated into a frontal system involving speech production and syntax. Its robust connectivity with the IFJa, FEF, and Area 55b makes it an interesting target for top-down modulation during linguistic and executive tasks.
3.2.5 Hierarchical Gateways and Connectors
These regions serve as routing hubs and convergence zones between early acoustic analysis and higher-order integration.
- PBelt: A4, A5: The primary “routers” exiting the auditory core. PBelt and A4 show effective connectivity to parietal regions 7AL, 8AM, 7PC. Rolls et al. (2023) - Cerebral Cortex suggests that PBelt, A4 and A5 might form a language-related dorsal pathway, adding them to the auditory where-stream. Glasser et al. (2016) - Nature parcellation on the other hand places A4 and A5 together with STSdp, STSda, STSvp, STSva, STGa, and TA2 in a region naming them auditory association cortex. This area rather belongs to the ventral what-stream, making a clear classification difficult. Ambiguities will be resolved and discussed in chapters 4.4 and 5. (wo auch immer ich das mache)
- PGi: Effective connectivity to semantic areas as STS, TGv, TGd and TE1a place PGi in the auditory what-pathway. Rolls (2022) - NeuroImage places PGi in Group 1 along with STSva, STSvp and TE1a and TGd.
- PSL, STV, TPOJ1: Multimodal convergence zones (Group 3 networks) bridging auditory semantics with visual and somatosensory inputs (Rolls (2022) - NeuroImage, Rolls et al. (2023) - Cerebral Cortex) showing effective connectivity with PBelt, A4 and A5. While PSL is anatomically integrated into the semantic network, functional models suggest it acts as an abstract linguistic interface rather than a primary auditory responder Dureux (2024). That’s why we placed these regions in the semantic what-pathway for the following analyses. TPOJ1 shows weak responses to non-vocal sounds according to Dureux (2024).
3.2.6 Tables
Table 1: Prefrontal Seed Regions
| Kürzel | Voller Name | Location (Stream) | Quelle |
|---|---|---|---|
| FEF | Frontal Eye Field | Prefrontal (Dorsal Attention) | Bedini & Baldauf (2021); Salmi et al. (2009) |
| IFJa | Anterior Inferior Frontal Junction | Prefrontal (Frontoparietal) | Bedini & Baldauf (2021) |
| IFJp | Posterior Inferior Frontal Junction | Prefrontal (Multiple-Demand) | Bedini & Baldauf (2021) |
Table 2: Where & How Stream (Dorsal)
| Kürzel | Voller Name | Location (Stream) | Quelle |
|---|---|---|---|
| 7AL | Area 7 Anterior Lateral | Dorsal (Where - Spatial) | Rolls et al. (2023) |
| 7Am | Area 7 Anterior Medial | Dorsal (Where - Spatial) | Rolls et al. (2023) |
| 7PC | Area 7 Posterior Capsular | Dorsal (Where - Spatial) | Rolls et al. (2023) |
| PF | Area PF (Inferior Parietal) | Dorsal (Where - Spatial) | Baker (2018) |
| PFop | Area PF Opercular | Dorsal (Where - Spatial) | Rauschecker & Scott (2009) |
| PFcm | Area PF Complex Medial | Dorsal (Where/Somatosensory) | Glasser (2016) |
| MT | Middle Temporal Area | Dorsal (Where - Motion) | Rolls et al. (2023) |
| MST | Medial Superior Temporal Area | Dorsal (Where - Motion) | Rolls et al. (2023) |
| 55b | Area 55b | Dorsal (How - Motor Relay) | Dureux (2024) |
| 44 | Area 44 (Pars Opercularis) | Dorsal (How - Motor) | Rolls et al. (2023) |
| OP4 | Frontal Opercular Area 4 | Dorsal (How - Motor interface) | Dureux (2024) |
| FOP1-3 | Frontal Operculum 1, 2, 3 | Dorsal (How - Motor planning) | Frühholz (2015) |
| 43 | Area 43 | Dorsal (How - Motor planning) | Frühholz (2015) |
| SCEF | Supp. & Cingulate Eye Field | Dorsal (How - Cingulate Attn.) | Dureux (2024) |
| A4 | Auditory Area 4 | Gateway (Sensory Router) | Rolls et al. (2023) |
| PBelt | Parabelt Complex | Gateway (Sensory Router) | Rolls et al. (2023) |
Table 3: What pathway (ventral)
| Kürzel | Voller Name | Location (Stream) | Quelle |
|---|---|---|---|
| A5 | Auditory Area 5 | Ventral (What - Semantic Gateway) | Rolls et al. (2022) |
| STGa | Superior Temporal Gyrus Ant. | Ventral (What - Identity) | Glasser (2016) |
| STSda/dp | STS Dorsal Ant. / Post. | Ventral (What - Semantic) | Rolls et al. (2023) |
| STSva/vp | STS Ventral Ant. / Post. | Ventral (What - Semantic) | Glasser (2016) |
| TA2 | Area TA2 | Ventral (What - Semantic) | Glasser (2016) |
| STV | Superior Temporal Visual Area | Ventral (What - Multimodal) | Rolls (2023) |
| TPOJ1 | Temp.-Par.-Occ. Junction 1 | Ventral (What - Convergence) | Rolls (2023) |
| PGi | Area PGi (Inferior Parietal) | Ventral (What - Visual Semantic) | Rolls (2022) |
| AVI | Anterior Ventral Insula | Ventral (What - Evaluation) | Dureux (2024) |
| 45 | Area 45 (Pars Triangularis) | Ventral (What - Semantic) | Rolls et al. (2023) |
| 47l | Area 47 Lateral | Ventral (What - Semantic) | Rolls et al. (2023) |
| IFSp | Inferior Frontal Sulcus Post. | Ventral (What - Semantic) | Dureux (2024) |
| TE1a | Area TE1 Anterior | Ventral (What - Periphery) | Rolls (2022) |
| TGd / TGv | Temporal Gyrus Dor. / Ven. | Ventral (What - Periphery) | Rolls (2022) |
| PSL | Perisylvian Language Area | Connector (Linguistic Interface) | Rolls (2023) |
Notes & Scrapbook
Hier Dinge abladen, die noch keinen Platz im Text haben, damit der Schreibfluss nicht stoppt.
see also
3.0 Methods
3.1 Data Acquisition & Preprocessing
3.3 Matrix Construction
3.4 Brain Behavior Correlation