The human brain is a complex organ with specialized regions that work together to enable cognitive functions. From the cerebral cortex overseeing higher-order processes to subcortical structures supporting emotions and memory, each part plays a crucial role in our mental abilities.

Brain damage can lead to specific cognitive deficits, highlighting the importance of each region. Meanwhile, hemispheric lateralization shows how the left and right sides of the brain specialize in different tasks, working in tandem to process information and guide our thoughts and behaviors.

Brain Anatomy and Cognitive Functions

Major brain structures and functions

• Cerebral cortex oversees higher-order cognitive processes
  • Frontal lobe manages executive functions controls motor movements and produces language (Broca's area)
  • Parietal lobe processes sensory input and maintains spatial awareness (body in space)
  • Temporal lobe handles auditory processing forms memories and comprehends language (Wernicke's area)
  • Occipital lobe processes visual information (color, shape, motion)
• Subcortical structures support various cognitive and emotional processes
  • Hippocampus consolidates memories and aids in spatial navigation (cognitive maps)
  • Amygdala processes emotions and facilitates fear conditioning (fight-or-flight response)
  • Basal ganglia control motor movements and form habits (procedural learning)
  • Thalamus relays sensory information and regulates attention (sensory gatekeeper)
• Cerebellum coordinates motor movements maintains balance and supports cognitive processing (timing, sequencing)
• Brainstem regulates autonomic functions and modulates arousal and consciousness (sleep-wake cycle)

Brain regions in cognitive processes

• Neural networks connect brain regions through functional and structural connectivity (white matter tracts)
• Cognitive processes involve multiple brain regions working together
  • Memory engages prefrontal cortex and hippocampus for encoding distributes storage across cortical areas and retrieves information using prefrontal cortex and hippocampus
  • Language production activates Broca's area and motor cortex while comprehension involves Wernicke's area and auditory cortex
  • Attention system includes alerting (brainstem, thalamus) orienting (parietal cortex, frontal eye fields) and executive control (prefrontal cortex)
• Integration of sensory information occurs in association areas (multisensory neurons)
• Top-down processing from prefrontal cortex influences sensory processing (attentional modulation)

Brain Damage and Lateralization

Brain damage and cognitive deficits

• Brain damage results from various causes
  1. Stroke interrupts blood flow leading to cell death
  2. Traumatic brain injury damages brain tissue through external force
  3. Neurodegenerative diseases progressively destroy neurons (Alzheimer's, Parkinson's)
• Specific cognitive deficits linked to damaged brain regions
  • Frontal lobe damage impairs executive functions (planning, decision-making)
  • Temporal lobe damage affects memory formation and retrieval (amnesia)
  • Parietal lobe damage causes spatial neglect (ignoring one side of space)
  • Occipital lobe damage leads to visual agnosia (inability to recognize objects)
• Neuroplasticity enables functional reorganization and compensatory strategies after brain injury
• Case studies illustrate effects of brain damage
  • Phineas Gage's frontal lobe injury altered personality and decision-making
  • H.M.'s bilateral hippocampal removal resulted in anterograde amnesia

Hemispheric lateralization in cognition

• Left hemisphere specializes in language processing logical reasoning and sequential processing (step-by-step analysis)
• Right hemisphere excels at spatial processing emotional interpretation and holistic processing (big picture thinking)
• Corpus callosum facilitates interhemispheric communication (information transfer between hemispheres)
• Specific functions show lateralization patterns
  • Handedness correlates with language lateralization (left hemisphere dominance in right-handed individuals)
  • Face recognition demonstrates right hemisphere advantage (holistic processing)
• Bilateral processing involves complementary roles of hemispheres in complex tasks (reading comprehension)
• Individual differences exist in lateralization patterns (atypical language lateralization in left-handed individuals)