Brodmann Areas and Functions
Motor Cortex Areas
- Located in the precentral gyrus (frontal lobe).
Area | Area | Function(s) |
Cortical Association Areas | ㅤ | • Idea generation & initiation of movement. |
Primary | 4 | • Execution of movement. |
Supplementary Motor Area | 6 | • Bimanual coordination. • Supplement both sides |
Pre-motor Cortex | 6 | • Postural setup. • Mirror neurons (imitation) • EP Tract start from Premotor cortex • Preparation motor - Preparation to immitate and set posture |
- Note: Sensory cortex is in Brodmann areas 3, 1, 2.
Location | Name |
44, 45 ↳ Inferior frontal gyrus | • Broca’s speech area - motor |
22 ↳ Superior temporal gyrus | • Wernicke’s speech area • sensory (Area 22, 40, 39) |
41, 42 ↳ Superior temporal gyrus / Heschl’s cortex | • Primary auditory area |
8 ↳ Middle frontal gyrus | • Frontal eye field (Horizontal gaze) • C/L conjugate eye movement lost |
4 ↳ Pre-Central gyrus ↳ in front of Central sulcus of Rolando) | • Primary motor area • C/L Hemiplegia |
6 ↳ Posterior part of all 3 frontal gyrus ↳ In front of area 4) | • Pre-motor area • Apraxia • Site of origin of extrapyramidal tract |
3, 1, 2 ↳ Post Central gyrus ↳ (Behind Central sulcus of Rolando) | • Primary somatosensory area • C/L Sen - Loss in face Applied • Phantom limb • Law of plasticity |
17, 18, 19 ↳ Concentric circles around Calcarine sulcus | • 17: Primary visual area • 18, 19: Visual association area |
5, 7 ↳ Superior Parietal lobule | • Somatosensory association area • Tactile agnosia |
↳ Inferior parietal lobule | • Hand-eye coordination |
Visual Cortex
- Primary visual cortex
- Area 17
- Located in posterior part of calcarine sulcus
- Lobe: Occipital
- Heavily myelinated
- Striate appearance:
- Striae of Gennasi (also known as striate cortex)
- Mnemonic: Genz vision brod anu → 17, 18, 19 yr olds
- Accessory visual areas
- Area 18 → Secondary visual cortex
- Area 19 → Tertiary visual cortex
Wernicke’s Sensory Speech Area (22)
- Present posteriorly on the superior temporal gyrus.
Wernicke’s aphasia / Receptive aphasia / Fluent aphasia / Sensory Aphasia:
- Patient cannot understand spoken or written language.
- Mnemonic:
- Where 2 (Wernicke 22)
- Whisky/Waatt → 220 Rs → 22
Broca’s Motor Speech Area (44, 45)
- Present on inferior frontal gyrus
- (44) Pars opercularis
- (45) Pars Triangularis
Broca’s aphasia / Expressive aphasia / Non-fluent aphasia /
Agrammatic aphasia / Motor Aphasia
- Speech becomes difficult.
- Patient understands spoken language.
- Broca’s and Wernicke’s speech areas are connected by
- Arcuate fasciculus
- Lesion in Arcuate Fasciculus:
- Conduction aphasia
Global aphasia
- Lesion in Broca’s, Wernicke’s, and Arcuate Fasciculus
- Middle Cerebral Artery stroke:
- (Motor + Sensory) aphasia =
A man arrives with aphasia. He is unable to name items, and his repetition is poor. However, comprehension, fluency, and understanding of written language are unchanged. He's presumably suffering from?
- Anomic aphasia
- Broca's aphasia
- Transcortical sensory aphasia
- Conduction aphasia
ANS
4
- If repetition preserved = Transcortical
- Fluency +/-
- Naming is not dependable for diagnosis
Sensory Homunculus
- Medial: Leg
- Lateral: Face
- Area of representation
- Proportional to functionality/use
- (not the physical size of the body part.)
- Maximum: (Based on use)
- Lip > Thumb
- Minimum:
- Hip, back, trunk
- No representation of visceral organs
- Visceral organ pain
- Referred to somatic structure with same embryonic origin.
Major Cortical Association Areas
Area | Functions |
Prefrontal Cortex • Anterior frontal lobe | • Executive functions: • Planning, decision-making • Working Memory (Short term) → Eg: Phone numbers |
Anterior nucleus of thalamus | • Recent memories • Relay station in the limbic circuit. |
Amygdala | • Associates memory with emotions • Especially fear • Applied: Kluver - Bucy syndrome • though not part of original Papez circuit, it's a part of limbic system |
Hippocampal formation | • Memory encoding. • Anterograde amnesia ↳ Lesions in hippocampus or Papez circuit. |
Mamillary bodies | • Recollective memory • Degeneration → Wernicke-Korsakoff psychosis • (seen in alcoholics) |
Parietal Association Cortex | • Spatial awareness • Damage can cause hemispatial neglect. • Parietal - Periphery - spatial awareness Inferior parietal lobule • Hand eye coordination Superior Parietal lobule • A/w Tactile agnosia |
Temporal Association Cortex | • Memory, object recognition, and language comprehension. • Includes Wernicke’s area on the dominant hemisphere. |
Inferior Temporal Cortex | • Face recognition by sight ↳ Prosopagnosia |
Limbic Association Area | • Part of limbic lobe; • Connects with hippocampus and amygdala • Involved in emotion, motivation, and memory. |
Entorhinal cortex (of limbic cortex) | • Associates memory with smell • Also in Spatial memory • Interface between hippocampus and neocortex. |
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