The insula forms a buried cortical surface within the Sylvian region. Frontoorbital, frontoparietal and temporal opercula overlie it; seeing an insular parcel requires understanding that depth relationship.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
AVI · anterior ventral insula
PoI2 · posterior insula
Compare
Select AVI and PoI2 in turn with the cortex transparent. They orient anterior ventral and posterior insular regions; the view is a transparency exercise, not an opercular dissection.
Read the neighbours
The central insular sulcus divides an anterior short-gyral region from a posterior long-gyral region.
HCP parcels subdivide the insular cortex differently from the gross gyral description.
Explain before revealing
Why does an insular parcel fail to behave like a patch on the exposed lateral convexity?
Explanation
Because the insula is covered by the opercula. The selected parcel belongs to a buried surface. Transparency may help locate it, but does not reproduce the anatomy or exposure of a surgical dissection.
In a surgical discussion
A lateral cortical landmark and a buried insular target are at different depths. Describe the overlying opercular relationship before discussing the deeper anatomy.
AVI and PoI2 orient anterior ventral and posterior insular cortex. The overlying opercula, intervening capsule/claustral layers and vessels need separate anatomical description. Monkey tracer results and interoception models do not install a human circuit in this atlas.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: Because the insula is covered by the opercula. The selected parcel belongs to a buried surface. Transparency may help locate it, but does not reproduce the anatomy or exposure of a surgical dissection.
This relationship draws on 4 cited sources.
Relationship 2 of 5 · atlas
Orient anterior and posterior insular regions
Orient
Gross short and long gyri, atlas parcels and functional descriptions are three different ways to describe insular cortex. Establish anterior and posterior before moving between them.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
PoI2 · posterior insula
AVI · anterior ventral insula
Compare
Compare posterior parcel PoI2 with AVI. Rotate to confirm their relative positions instead of inferring anterior from the screen’s left edge.
Read the neighbours
The central insular sulcus is a gross anatomical divider; the short/long-gyral pattern has individual variation.
PoI2 and AVI identify reference parcels, not the outlines of all posterior or anterior gyri.
Explain before revealing
Does the AVI label outline all the anterior short insular gyri?
Explanation
No. It identifies an HCP parcel in anterior ventral insula. Gross gyri and multimodal parcels are different subdivisions. Use both descriptions appropriately without treating one as an exact replacement for the other.
In a surgical discussion
An insular-lesion description should specify anterior/posterior and superior/inferior relationships. The single word “insula” hides substantial spatial detail.
AVI and PoI2 orient anterior ventral and posterior insular cortex. The overlying opercula, intervening capsule/claustral layers and vessels need separate anatomical description. Monkey tracer results and interoception models do not install a human circuit in this atlas.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: No. It identifies an HCP parcel in anterior ventral insula. Gross gyri and multimodal parcels are different subdivisions. Use both descriptions appropriately without treating one as an exact replacement for the other.
This relationship draws on 4 cited sources.
Relationship 3 of 5 · atlas
Place the lentiform complex deeper than insula
Orient
The insular surface is the lateral face of the central core. Deep to it lie capsule and claustral layers before the putamen and pallidum; the internal capsule lies further medially.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
PoI2 · posterior insula
Putamen
Globus pallidus
Thalamus (gross)
Compare
Compare the insular reference with putamen and pallidum, then locate thalamus medially. The thin capsule layers and claustrum are not separately modelled here.
Read the neighbours
From lateral to medial: insular cortex, extreme capsule, claustrum, external capsule, putamen, pallidum, then internal capsule.
Beyond the internal capsule, the medial neighbour changes with anteroposterior level: caudate head anteriorly and thalamus posteriorly.
Explain before revealing
Where does the claustrum sit in the sequence from insula to putamen, and which capsule separates it from putamen?
Explanation
The claustrum lies between the extreme capsule laterally and external capsule medially. The external capsule separates it from putamen. These thin layers are omitted from the render, so use the visible insula and putamen as the outer references for a sequence learned from sectional or dissection anatomy.
In a surgical discussion
A deeper insular extension brings the lentiform and internal-capsular relationships into the discussion. Projection pathways and their blood supply can account for motor consequences beyond a cortical insular description.
AVI and PoI2 orient anterior ventral and posterior insular cortex. The overlying opercula, intervening capsule/claustral layers and vessels need separate anatomical description. Monkey tracer results and interoception models do not install a human circuit in this atlas.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: The claustrum lies between the extreme capsule laterally and external capsule medially. The external capsule separates it from putamen. These thin layers are omitted from the render, so use the visible insula and putamen as the outer references for a sequence learned from sectional or dissection anatomy.
This relationship draws on 5 cited sources.
Relationship 4 of 5 · conceptual model
Add a functional framework without inventing a circuit
Orient
Interoception concerns internal bodily state. Craig’s framework relates posterior and anterior insular processing to bodily representation and feeling; it is a conceptual account, not a recording played by this atlas.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
PoI2 · posterior insula
AVI · anterior ventral insula
Thalamus (gross)
Compare
Compare the anterior and posterior reference parcels, then point out which relay nuclei and connecting edges would be needed to render a specific proposed circuit. They are not installed.
Read the neighbours
Gross thalamus cannot substitute for a named relay nucleus such as VMpo.
Mesulam and Mufson’s insular output study used tracers in old-world monkeys. That experimental anatomy is distinct from Craig’s conceptual synthesis and does not establish the same circuit in an individual human.
A sequence of teaching highlights establishes the order of explanation, not neural timing or direction.
Explain before revealing
If the highlight moves from posterior to anterior insula, what has actually moved?
Explanation
The focus of the explanation. No neural signal has been measured, and no latency, causal sequence or individual connection has been established. The framework and its evidence remain separate from the reference geometry.
In a surgical discussion
A symptom involving bodily sensation or awareness can motivate an insular-network question. It does not allow an atlas parcel to diagnose the mechanism of an individual symptom.
AVI and PoI2 orient anterior ventral and posterior insular cortex. The overlying opercula, intervening capsule/claustral layers and vessels need separate anatomical description. Monkey tracer results and interoception models do not install a human circuit in this atlas.
The installed Melbourne scale-1 thalamus is gross anatomy. It does not segment lateral geniculate, VMpo or other relay nuclei; no named nucleus can be inferred from the outline.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: The focus of the explanation. No neural signal has been measured, and no latency, causal sequence or individual connection has been established. The framework and its evidence remain separate from the reference geometry.
This relationship draws on 5 cited sources.
Relationship 5 of 5 · schematic
Present an insular lesion in anatomical layers
Orient
Hypothetical case: a left insular lesion extends toward the lentiform complex. Picture naming is preserved. Build an anatomical account of the surface, depth and neighbouring systems before interpreting the functional observation.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
AVI · anterior ventral insula
PoI2 · posterior insula
Putamen
Compare
Start with the insular parcel, identify the opercular relationship, then describe the deep lentiform and capsular neighbourhood. State which of those layers are absent from this render.
Read the neighbours
A useful account includes surface, depth and neighbouring systems.
A proposed functional framework can complement that account but does not supply missing vessels, nuclei or tissue planes.
Explain before revealing
Which missing anatomical and functional observations could change your account of this insular lesion, despite preserved naming?
Explanation
Establish the lesion’s relationship to the lentiform complex, internal capsule and relevant vessels on individual imaging. Define the language tasks and baseline performance: preserved picture naming does not characterize every language operation. New motor findings would also raise projection-pathway and vascular questions. The atlas has no vessel layer or individual functional map, so those uncertainties remain unresolved here.
In a surgical discussion
Medial extension raises projection-pathway and lenticulostriate vascular questions. This atlas has no vascular layer, so the relevant vessels and their relation to the lesion cannot be assessed here. Keep that missing anatomy explicit in the layered case description.
AVI and PoI2 orient anterior ventral and posterior insular cortex. The overlying opercula, intervening capsule/claustral layers and vessels need separate anatomical description. Monkey tracer results and interoception models do not install a human circuit in this atlas.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: Establish the lesion’s relationship to the lentiform complex, internal capsule and relevant vessels on individual imaging. Define the language tasks and baseline performance: preserved picture naming does not characterize every language operation. New motor findings would also raise projection-pathway and vascular questions. The atlas has no vessel layer or individual functional map, so those uncertainties remain unresolved here.
This relationship draws on 5 cited sources.
Recap
A left insular lesion extends toward the lentiform complex despite preserved naming. Which anatomical and functional observations are still needed?
Orient the buried insular surface and its opercular relationships.
Describe the capsule, claustral and lentiform sequence while naming the layers absent from the scene.
Add projection-pathway and vascular questions when explaining medial extension.
Review the final explanation
Establish the lesion’s relationship to the lentiform complex, internal capsule and relevant vessels on individual imaging. Define the language tasks and baseline performance: preserved picture naming does not characterize every language operation. New motor findings would also raise projection-pathway and vascular questions. The atlas has no vessel layer or individual functional map, so those uncertainties remain unresolved here.
HCP population reference built from converging cortical features. A parcel boundary here is a group boundary; it does not locate one person’s functional border and it has not been registered to any individual in this viewer.
Stepwise human dissections of the insula, capsules, basal ganglia and thalamus. Gross atlas meshes illustrate only part of these layered relationships.
Provenance for the Melbourne Subcortex Atlas scale-1 meshes rendered here. Scale 1 is the coarsest level: anterior and posterior thalamus are merged and no brainstem nucleus is included.
Awake surgery series of 17 dominant-hemisphere low-grade gliomas. Semantic paraphasias supported a ventral pathway hypothesis, partly corresponding to IFOF; no measured stimulation sites are installed here.