Rucete ✏ Campbell Biology In a Nutshell
Unit 7 ANIMAL FORM AND FUNCTION — Concept 49.3 The Cerebral Cortex Controls Voluntary Movement and Cognitive Functions
The cerebral cortex—the brain’s outer layer—is responsible for higher cognitive functions like language, memory, and consciousness, as well as for processing sensory input and initiating voluntary movement. Its complex structure and regional specialization enable the brain’s remarkable capabilities.
1. Structure and Function of the Cerebral Cortex
- Cerebrum: largest brain region; cerebral cortex is its surface layer
- Functions: sensory processing, association, decision-making, motor control
- Four lobes:
- Frontal: planning, decision-making, motor control
- Parietal: touch and spatial awareness
- Occipital: vision
- Temporal: hearing and language
2. Information Flow in the Cortex
- Sensory input → primary sensory areas → association areas → prefrontal cortex → motor cortex
- Motor cortex: sends signals to muscles
- Somatosensory cortex: receives body sensory signals
- Both are body-mapped with larger areas for hands, face, etc.
3. Language Centers
- Broca’s area (left frontal): speech production
- Wernicke’s area (left temporal): language comprehension
- PET scans show distinct activation during speaking, listening, and reading
- Damage: Broca’s → speech loss; Wernicke’s → comprehension loss
4. Lateralization and Split-Brain
- Left hemisphere: language, logic, math
- Right hemisphere: spatial recognition, emotion, facial identification
- Corpus callosum: connects hemispheres
- Split-brain patients show hemisphere-specific processing
5. Frontal Lobe and Executive Function
- Prefrontal cortex: temperament, planning, emotional regulation
- Phineas Gage’s injury revealed role in behavior and self-control
- Lobotomies and tumors in this region affect personality
6. Cognitive Evolution in Vertebrates
- All vertebrates share basic brain architecture
- Mammals: layered cortex with folds for surface area
- Birds: nuclear pallium clusters perform similar cognitive roles
- Birds like crows/parrots show problem-solving and memory despite lacking cortex layers
In a Nutshell
The cerebral cortex is the seat of human thought, enabling language, decision-making, memory, and voluntary movement. Its region-specific functions, hemispheric lateralization, and evolutionary flexibility explain how diverse animals achieve complex behavior. Whether layered (in humans) or clustered (in birds), brain structure reflects function and intelligence.