Brain Atlas
Major regions first, interlinked circuits second
Start with specialization: what each major brain region is best known for when examined on its own.
Convergence overlays
Read anatomy as vascular, visual, brainstem, and loop systems
These overlays turn the atlas into a landing zone for the rest of the app rather than a list of isolated regions.
Clinical frame
Middle cerebral territory emphasis
Use this overlay when aphasia, neglect, gaze deviation, and face-arm predominant deficits travel together and the cortical syndrome feels lateral rather than medial.
Why this overlay matters
The most localizing clue is not the infarct name but the cortical package: gaze, language, neglect, face-arm sensorimotor signs, and field involvement clustering in one lateral hemispheric distribution.
Decisive next data
- • Language screen, neglect testing, and gaze preference at the bedside
- • Vascular imaging that distinguishes large-vessel cortical involvement from a deep perforator pattern
Overlay regions
Frontal eye and executive signs · Prefrontal Cortex
Explains gaze preference and executive collapse in large lateral hemispheric syndromes.
Face-arm motor output · Motor Cortex
Captures the classic lateral sensorimotor bias.
Face-arm sensory integration · Somatosensory Cortex
Adds cortical sensory and neglect-adjacent findings.
Spatial weighting and neglect · Parietal Association Cortex
Lateral parietal involvement explains extinction, neglect, and scene-scanning failure that often ride with MCA syndromes.
Autonomic and salience consequences · Insula
Insular extension helps explain visceral alarm, autonomic lability, and the sense that the body is suddenly wrong.
Language and semantic cortex · Temporal Cortex
Explains dominant-hemisphere aphasic patterns.
Field-cut neighborhood · Occipital Cortex
Posterior extension helps explain homonymous visual loss when present.
Case Mode
Practice consult-level localization before the reveal
Treat each vignette like senior consult rounds: formulate the syndrome, rank the localization hierarchy, name the most decisive next data, and then compare your working localization against the strongest network-level target.
Study progress
Track your case accuracy inside this module
Cases completed
0/ 9
Correct reveals
0
Accuracy
0%
Training stage
Post-clinical anatomical convergence
Post-clinical objectives
- • Separate vascular-territory, visual-stream, loop, and brainstem long-tract explanations before naming a disease.
- • Reject weaker competing localizations using exam asymmetry, cortical signs, negative findings, and network logic.
- • Use anterior cingulate, insular, hypothalamic, and parietal-association findings to distinguish motivational arrest, autonomic salience syndromes, and spatial-attention failures from simpler relay lesions.
Clinical vignette
Planning failure after frontal injury
A patient can speak and move but cannot organize multi-step tasks or suppress impulsive responses.
Chief complaint
Family reports severe disorganization and poor judgment after a head injury.
History
The patient forgets goals halfway through tasks, perseverates on the wrong rule, and becomes impulsive when asked to switch plans.
Syndrome frame
A frontal executive syndrome with impaired set maintenance, inhibitory control, and behavioral regulation, but without a primary aphasic, pyramidal, or cerebellar pattern.
Exam findings
- • Poor set shifting on executive testing
- • Marked distractibility with intact primary strength and sensation
- • Behavioral disinhibition without aphasia or cerebellar ataxia
Prompt
Which region is the best localization target for this syndrome, and why does that region fit better than a purely motor or sensory explanation?
- Look for the region that keeps goals online and suppresses distractions.
- The patient has a control problem, not a weakness problem.
Localization cues
- • The dominant deficit is failure of task set maintenance and inhibition.
- • Primary cortical outputs are largely preserved, so the problem lies upstream of execution.
Differential traps
- • Do not mislabel slowed or chaotic behavior as primary motor weakness.
- • Poor recall during distracted testing can be secondary to executive failure rather than pure hippocampal amnesia.
Next data to request
- • Formal set-shifting or Stroop-style testing to show impaired top-down control.
- • A careful language screen to exclude aphasia masquerading as disorganization.
Current pick: Prefrontal Cortex
Functional map
Regional specialization
Prefrontal Cortex
Keeps goals online, suppresses distractions, and lets you plan beyond the present moment.
Core functions
- • Executive control
- • Working memory
- • Decision-making
- • Inhibitory control
Signature tasks
- • Rule switching
- • Delayed-response tasks
- • Planning multi-step behavior
Clinical link
Damage produces dysexecutive syndrome: poor planning, impulsivity, and difficulty maintaining goals.
Compare mode
Selected region versus anatomical rival
Selected: PFC
Prefrontal Cortex
Keeps goals online, suppresses distractions, and lets you plan beyond the present moment.
Damage produces dysexecutive syndrome: poor planning, impulsivity, and difficulty maintaining goals.
Compare to: TH
Thalamus
Acts as a relay and state-dependent gate for sensory, motor, and cognitive traffic.
Lesions can disrupt consciousness, sensation, memory, or motor coordination depending on nucleus involved.
Why the overlay prefers the selected network
Lacunar and deep lesions can create pure motor or sensory syndromes, but they do not usually assemble the full cortical package of gaze, language, neglect, and field phenomena.
How to read Chapter 1
Principle 1
Most brain communication is recurrent rather than one-way: cortex sends down, subcortex sends back, and both reshape each other.
Principle 2
Hub regions such as the thalamus and prefrontal cortex matter because they coordinate timing and routing, not because they work alone.
Principle 3
Clinical syndromes often reflect broken loops rather than isolated damage to a single named structure.
Principle 4
Salience and autonomic symptoms localize best when you can connect interoception, motivation, and body-state output in one network instead of splitting them into separate complaints.