Start with a relationship: the precentral gyrus lies anterior to the central sulcus; the postcentral gyrus lies posterior. The atlas labels 4 and 3b help you compare its two banks.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
4 · precentral
3b · postcentral
6d · dorsal premotor
Compare
Use the structure buttons to alternate between 4 and 3b. Rotate slightly toward the vertex and follow their shared central-region relationship; do not try to memorize the parcel outline.
Read the neighbours
The central region continues from the lateral gyri onto the medial paracentral lobule.
6d provides premotor context anterior to the central region. These parcel labels subdivide cortex; they are not names for entire gyri.
Explain before revealing
A lesion approaches the central sulcus from anterior. Which cortical bank is encountered first, and how would your anatomical emphasis change for a lesion approaching from posterior?
Explanation
From anterior, the precentral bank (area 4) is met first, so the primary motor relationship leads the account. From posterior, the postcentral bank (area 3b) is met first and the somatosensory relationship leads. In either case, extend the account into the underlying white matter. The surface relationship helps frame the examination; it does not by itself predict the deficit.
In a surgical discussion
In a perirolandic discussion, describe both the cortical bank and the white matter beneath it. A gyrus name alone leaves the subcortical relationship unexplained.
HCP-MMP1 subdivides the central region into population reference labels, including primary motor, premotor, supplementary/cingulate and somatosensory territories. A parcel boundary does not define an individual functional boundary.
A group-average cortical surface with a population parcellation, a population-averaged bundle atlas, and gross subcortical meshes. No patient image, no registration, no functional map, no brainstem or thalamic nuclei.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: From anterior, the precentral bank (area 4) is met first, so the primary motor relationship leads the account. From posterior, the postcentral bank (area 3b) is met first and the somatosensory relationship leads. In either case, extend the account into the underlying white matter. The surface relationship helps frame the examination; it does not by itself predict the deficit.
This relationship draws on 5 cited sources.
Relationship 2 of 10 · atlas
Continue onto the medial motor surface
Orient
The medial view brings the paracentral region and supplementary motor territory into the same frame. Compare posterior medial premotor parcel 6mp with the more anterior 6ma and area 4.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
6mp · posterior medial premotor
6ma · anterior medial premotor
SCEF · supplementary/cingulate
4 · precentral
Compare
Compare 6mp, 6ma and 4 in the medial view, then inspect SCEF on the adjacent supplementary/cingulate territory. Say which way is anterior before describing the relationships.
Read the neighbours
6mp and 6ma orient posterior and anterior medial premotor cortex. SCEF adds the adjacent supplementary/cingulate reference, so the medial-frontal account extends beyond two premotor parcels.
Movement initiation and movement execution are distinct clinical observations; a medial frontal deficit need not be explained by destruction of area 4.
Explain before revealing
Why can a medial frontal lesion impair movement even when the precentral cortex is preserved?
Explanation
Motor control includes medial premotor systems as well as primary motor cortex and descending pathways. A deficit of initiation is one possibility to consider. Its clinical characterization and time course must distinguish it from weakness caused by capsular, cortical or vascular injury.
In a surgical discussion
The cited medial frontal surgical series describes postoperative motor deficits after SMA-region resection. Use it to discuss an additional mechanism of impaired movement; recovery in that series is not an individual prognosis.
HCP-MMP1 subdivides the central region into population reference labels, including primary motor, premotor, supplementary/cingulate and somatosensory territories. A parcel boundary does not define an individual functional boundary.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: Motor control includes medial premotor systems as well as primary motor cortex and descending pathways. A deficit of initiation is one possibility to consider. Its clinical characterization and time course must distinguish it from weakness caused by capsular, cortical or vascular injury.
This relationship draws on 4 cited sources.
Relationship 3 of 10 · reconstruction
Follow the fan into a descending corridor
Orient
The corticospinal reconstruction changes shape with depth: a broad supratentorial fan converges toward a narrower descending course. Follow that change before adding neighbouring systems.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
CST · corticospinal tract
4 · precentral
Compare
Trace the displayed CST from its broad superior portion toward its narrow inferior portion. Rotate to an anterior view, then restore the lesson scene and compare the two projections.
Read the neighbours
Corona radiata describes the radiating white matter above the capsule; it is a region containing several fibre populations.
The displayed CST sample provides a course to inspect. Its visible endpoints are not proof that each line terminates in the highlighted parcel.
Explain before revealing
Why can two lesions beneath the same cortical region involve very different white matter relationships?
Explanation
The pathways fan out superiorly and converge with depth. Their neighbours and compactness therefore change along the course. Describe the level of the lesion as well as the overlying gyrus; the atlas supplies an orientation exercise, not a patient-specific lesion map.
In a surgical discussion
Depth changes the neighbourhood of a lesion: a superficial white matter relationship is different from a compact deep corridor. A lateral screenshot cannot substitute for evaluating the relationship in multiple planes.
A descending reconstruction from a population atlas, sampled for display. Its side, family and source identify what is shown; its endpoints and line count do not identify an individual cortical origin, body part or axon count.
Projection pathways converge from the corona radiata toward the capsule. Use caudate or thalamus medially and the lentiform complex laterally to identify the level. The capsule is not segmented, and the displayed samples do not resolve its internal fibre ordering.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: The pathways fan out superiorly and converge with depth. Their neighbours and compactness therefore change along the course. Describe the level of the lesion as well as the overlying gyrus; the atlas supplies an orientation exercise, not a patient-specific lesion map.
This relationship draws on 5 cited sources.
Relationship 4 of 10 · reconstruction
Motor-related origins extend beyond area 4
Orient
A descending system is not adequately described by a single cortical origin. Compare the primary motor, premotor and somatosensory reference parcels around the central region.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
4 · precentral
6d · dorsal premotor
3b · postcentral
Compare
Alternate between 4, 6d and 3b. Keep the dim CST in view as a spatial reference, without treating every neighbouring parcel as a verified endpoint of this sample.
Read the neighbours
Usuda and colleagues reconstructed descending contributions from several motor-related and somatosensory regions in healthy volunteers.
Their tractography estimates describe one method and cohort; the displayed atlas does not separate those contributions into individual origin-specific bundles.
Explain before revealing
Does a postcentral origin make a descending streamline a primary motor-cortex fibre?
Explanation
No. Cortical origin, anatomical course and functional role are different descriptors. A pathway may descend from a somatosensory region without becoming an area-4 origin. This scene lets you compare labels, but does not classify its streamlines by origin.
In a surgical discussion
A proposed explanation of motor risk should consider premotor and postcentral relationships as well as area 4. Sparing one named parcel does not describe the full motor system.
A descending reconstruction from a population atlas, sampled for display. Its side, family and source identify what is shown; its endpoints and line count do not identify an individual cortical origin, body part or axon count.
HCP-MMP1 subdivides the central region into population reference labels, including primary motor, premotor, supplementary/cingulate and somatosensory territories. A parcel boundary does not define an individual functional boundary.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: No. Cortical origin, anatomical course and functional role are different descriptors. A pathway may descend from a somatosensory region without becoming an area-4 origin. This scene lets you compare labels, but does not classify its streamlines by origin.
This relationship draws on 5 cited sources.
Relationship 5 of 10 · atlas
Read the posterior limb by its neighbours
Orient
The posterior limb of the internal capsule lies between the thalamus medially and the lentiform nucleus laterally. The lentiform nucleus comprises putamen and globus pallidus.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
Thalamus (gross)
Putamen
Globus pallidus
CBT · corticobulbar tract
Compare
Find thalamus, putamen and pallidum around the descending sample. Use their relative positions to describe the corridor; the internal capsule itself is not a segmented mesh here.
Read the neighbours
Putamen is lateral to the pallidum; the capsular corridor is medial to the lentiform complex.
Discuss corticobulbar fibres at the genu and anterior posterior limb as a classical orientation, then contrast the more posterior localization reported by Yim. The ghosted CBT and frontopontine samples compare projection courses; they cannot resolve this difference or individual capsular fibre ordering.
Explain before revealing
On a sectional image, a white-matter interval has thalamus medially and pallidum laterally. Identify the capsular relationship and explain what would change in an anterior-limb section.
Explanation
This is the posterior-limb relationship. The lentiform complex remains lateral, while the medial neighbour in an anterior-limb section is caudate head. Use these grey-matter landmarks to establish the level before discussing the projection fibres within the interval.
In a surgical discussion
For a deep lesion, name the grey-matter structures on either side of the white matter relationship. This is more informative than describing a line as simply “near the basal ganglia.”
Projection pathways converge from the corona radiata toward the capsule. Use caudate or thalamus medially and the lentiform complex laterally to identify the level. The capsule is not segmented, and the displayed samples do not resolve its internal fibre ordering.
The frontopontine sample supplies context near the descending CST. The broader corticopontine account rests partly on primate tracer work; those experiments do not verify each line or cortical origin of this human atlas sample.
Putamen, globus pallidus, caudate and thalamus at the coarsest scale of a group subcortical parcellation. Anterior and posterior thalamus are merged into one mesh; no nucleus is individually named or targetable here.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: This is the posterior-limb relationship. The lentiform complex remains lateral, while the medial neighbour in an anterior-limb section is caudate head. Use these grey-matter landmarks to establish the level before discussing the projection fibres within the interval.
This relationship draws on 7 cited sources.
Relationship 6 of 10 · atlas
Distinguish anterior from posterior capsule
Orient
Moving anteriorly changes the medial neighbour of the capsule from thalamus toward caudate head. The lentiform complex remains lateral. This distinguishes two capsular relationships without relying on colour.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
Caudate nucleus
Thalamus (gross)
Putamen
Globus pallidus
Compare
Compare caudate and thalamus while keeping putamen and pallidum visible. Describe the anterior and posterior relationships aloud; do not call every interval the posterior limb.
Read the neighbours
The anterior limb is related to caudate head medially; the posterior limb is related to thalamus medially.
The genu is the bend between the limbs. This atlas does not segment that bend or its individual fibre subdivisions.
Explain before revealing
What changes on the medial side as you move from the anterior to the posterior capsular relationship?
Explanation
The reference changes from caudate head to thalamus. Keep putamen and pallidum as the lateral reference while changing the viewing angle. The exercise identifies neighbouring structures; it does not identify a safe passage between them.
In a surgical discussion
The clinical significance of a deep frontal trajectory depends on its position along the capsule, not just its distance from a basal-ganglia outline. Vascular relationships require additional anatomy beyond these meshes.
Putamen, globus pallidus, caudate and thalamus at the coarsest scale of a group subcortical parcellation. Anterior and posterior thalamus are merged into one mesh; no nucleus is individually named or targetable here.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: The reference changes from caudate head to thalamus. Keep putamen and pallidum as the lateral reference while changing the viewing angle. The exercise identifies neighbouring structures; it does not identify a safe passage between them.
This relationship draws on 2 cited sources.
Relationship 7 of 10 · reconstruction
Add sensory pathways to the deep region
Orient
The thalamus is also a reference for sensory systems. Compare the medial lemniscus and superior thalamic radiation samples with the descending corticospinal course.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
ML · medial lemniscus
TR_S · superior thalamic radiation
Thalamus (gross)
Compare
Follow ML toward the thalamic region and TR_S toward the cortex. Separate the two named samples; the viewer does not join them across a measured synapse.
Read the neighbours
The displayed thalamus is a gross structure, not an atlas of individual relay nuclei.
Anatomical direction is knowledge brought to the image. Neither line colour nor a display sweep identifies afferent versus efferent signalling.
Explain before revealing
Can a continuous-looking ML–thalamus–cortex arrangement prove a single continuous axon?
Explanation
No. These are separate atlas objects. Spatial proximity does not establish a synapse, continuity or direction. Use the thalamus to orient the anatomical relay relationship while keeping its nuclei and the individual connections unresolved.
In a surgical discussion
When discussing a deep sensorimotor deficit, characterize sensation as well as strength. A motor-only bundle selection can hide a neighbouring sensory relationship.
Medial lemniscus and the anterior, superior and posterior thalamic radiations. The render encodes geometry only: it cannot show direction of conduction, so “ascending” is anatomy you bring to the picture.
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: No. These are separate atlas objects. Spatial proximity does not establish a synapse, continuity or direction. Use the thalamus to orient the anatomical relay relationship while keeping its nuclei and the individual connections unresolved.
This relationship draws on 3 cited sources.
Relationship 8 of 10 · reconstruction
Distinguish cerebellar input and output routes
Orient
Motor coordination also involves cerebellar connections. Compare the middle and superior cerebellar peduncles with the dentatorubrothalamic sample and thalamic reference.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
SCP · superior cerebellar peduncle
MCP · middle cerebellar peduncle
DRTT · dentatorubrothalamic tract
Compare
Use the posterior view to identify the two peduncle samples, then follow DRTT toward the thalamic region. The dentate and red nuclei are not represented by meshes.
Read the neighbours
The middle cerebellar peduncle belongs to the pontocerebellar input route; the superior peduncle carries major cerebellar output pathways.
The DRTT sample illustrates a different relationship from the descending CST. Its name does not mean that all named nuclei have been rendered.
Explain before revealing
Which peduncle would you discuss when tracing a major cerebellar output route toward thalamus?
Explanation
The superior cerebellar peduncle. Contrast it with the middle peduncle in the pontocerebellar input route. These connections participate in a larger system; the separate atlas samples do not form a fully resolved circuit.
In a surgical discussion
The cited paediatric posterior-fossa cohort associated postoperative syndrome with proximal dentatothalamocortical pathway injury. Use that evidence to broaden the anatomical discussion beyond the CST, without predicting an individual outcome.
Middle and superior peduncle samples and the dentatorubrothalamic reconstruction orient parts of a larger system. The dentate, pontine and red nuclei are absent. A cited paediatric posterior-fossa association is not an individual prediction or proof of a continuous rendered circuit.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: The superior cerebellar peduncle. Contrast it with the middle peduncle in the pontocerebellar input route. These connections participate in a larger system; the separate atlas samples do not form a fully resolved circuit.
This relationship draws on 3 cited sources.
Relationship 9 of 10 · functional measurement
Separate a motor map from a parcel map
Orient
Return to area 4. A cortical label helps orientation, but it does not divide this brain into measured hand, foot and mouth territories.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
4 · precentral
6mp · posterior medial premotor
Compare
Inspect area 4 and its medial continuation. Explain what an additional functional map would need to contribute; there is no hidden homunculus to reveal in the controls.
Read the neighbours
Gordon and colleagues found effector-related regions alternating with regions linked to action control using precision functional MRI.
That organization is a functional finding in other participants. The atlas contour supplies a different kind of boundary.
Explain before revealing
Would highlighting the upper part of parcel 4 establish the foot representation in an individual?
Explanation
No. It would establish which portion of a population parcel you chose to display. Identifying an individual functional territory needs an appropriate functional observation; its task and localization must accompany the claim.
In a surgical discussion
An anatomical hypothesis and an individual functional observation should remain separately identifiable when discussing a motor-area lesion. A familiar surface location does not make the missing measurement available.
A functional organization measured with precision fMRI in other participants. It is discussed here and deliberately not painted onto the surface, because that measurement is not part of this dataset.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: No. It would establish which portion of a population parcel you chose to display. Identifying an individual functional territory needs an appropriate functional observation; its task and localization must accompany the claim.
This relationship draws on 2 cited sources.
Relationship 10 of 10 · schematic
Explain a motor deficit at three levels
Orient
Build a short anatomical differential: cortical bank, deep projection corridor, and distributed motor control. Use a specific relationship for each explanation.
Select each structure to light it on the atlas, then rotate until you can name what lies in front, behind and beneath it.
Targets
4 · precentral
6mp · posterior medial premotor
Thalamus (gross)
Putamen
Compare
Compare the area-4 and medial-premotor references, then identify thalamus and putamen around CST. Use Restore lesson scene to return after inspecting a structure.
Read the neighbours
At the surface, distinguish primary motor from premotor and postcentral relationships.
At depth, describe capsular neighbours; for coordination or initiation, consider systems beyond a single descending bundle.
Explain before revealing
Give one reason a preserved area-4 outline cannot establish preservation of motor function.
Explanation
The outline says nothing about the state of the underlying descending pathways, adjacent blood supply or connected premotor systems. A useful account specifies the observed deficit and anatomical level, then checks the individual evidence rather than treating an atlas selection as a clinical finding.
In a surgical discussion
Teaching vignette: a resident attributes every postoperative movement problem to CST injury. Explain what the examination and individual imaging would need to distinguish before accepting that account.
A group-average cortical surface with a population parcellation, a population-averaged bundle atlas, and gross subcortical meshes. No patient image, no registration, no functional map, no brainstem or thalamic nuclei.
Ask the learner to answer before opening the explanation. Compare the answer with the named structures and the cited method. Teaching point: The outline says nothing about the state of the underlying descending pathways, adjacent blood supply or connected premotor systems. A useful account specifies the observed deficit and anatomical level, then checks the individual evidence rather than treating an atlas selection as a clinical finding.
This relationship draws on 7 cited sources.
Recap
How can you explain a motor deficit when the area-4 outline is preserved?
Use the two banks of the central sulcus to establish the cortical relationship.
Read the posterior capsular corridor between thalamus and the lentiform complex.
Explain movement at cortical, projection-pathway and distributed-control levels.
Review the final explanation
The outline says nothing about the state of the underlying descending pathways, adjacent blood supply or connected premotor systems. A useful account specifies the observed deficit and anatomical level, then checks the individual evidence rather than treating an atlas selection as a clinical finding.
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.
Provenance for the S1200 group-average surface rendered here. A group-average midthickness surface is a population object; individual gyral and sulcal anatomy differs from it.
Provenance for the HCP1065 population-averaged bundles rendered here. Every displayed line is an average-space reconstruction sampled for display; it is not a patient’s pathway and carries no direction of conduction.
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.
Surgical series correlating resection extent with postoperative deficit and recovery. The recovery pattern belongs to that series and its follow-up, not to any picture on this screen.
Healthy-volunteer tractography comparing descending contributions by cortical origin. Streamline distributions depend on acquisition, model and ROI recipe; they are not axon counts and they are not transferable to a patient.
Stepwise human dissections of the insula, capsules, basal ganglia and thalamus. Gross atlas meshes illustrate only part of these layered relationships.
Challenge dataset with a defined ground truth and many submitted pipelines. Its false-positive findings motivate caution; its error figures belong to that challenge and are not an error estimate for this atlas.
Early DTI tractography of capsular organization, published explicitly against prior reports. A group ordering derived from one method is not a map you can transfer to an individual capsule.
CT and clinical observations of restricted internal-capsular lesions support classical motor localization while allowing individual variation. A lesion-based inference is not a resolved fibre map in this atlas.
Capsular-infarct observations and a separate DTI sample placed corticobulbar relationships more posteriorly than classical genu accounts. Findings depend on level and method; this atlas cannot adjudicate the individual distribution.
Tracer experiments in rhesus monkey. Species and experimental scope limit translation; a monkey tracer result does not verify a human population reconstruction.
Probabilistic diffusion tractography relating thalamic territory to cortical target. A connectivity-defined territory is a model output, not a nuclear boundary, and this viewer ships no thalamic nuclei.
Clinical–imaging correlation in a paediatric posterior fossa cohort. An association between imaged tract involvement and a postoperative syndrome is not a prediction rule for an individual, and nothing in this scene measures it.
Precision functional MRI and connectivity in a small set of deeply sampled participants. Effector and inter-effector observations are task, modality and population dependent, and none of that map is installed in this viewer.