Brain Function and Lateralization - Google Docs.pdf
Transcript
rain Function and Lateralization B Functional Categorization Primary sensory areas Primary motor area Association areas Lobes of the Brain Frontal lobe ○ Executive function, risk-taking, planning,...
rain Function and Lateralization B Functional Categorization Primary sensory areas Primary motor area Association areas Lobes of the Brain Frontal lobe ○ Executive function, risk-taking, planning, creativity, emotions, smell, muscle movements, personality...and much more! ○ Includes the prefrontal cortex, the primary motor cortex, Broca’s area (left hemisphere) ○ Disorders associated with the frontal lobe Apraxias = disorders of action Aphasias = disorders of language (e.g., Broca’s/nonfluent aphasia) Personality… Parietal lobe ○ Perception, pain, integration of sensory input ○ Includes the primary somatosensory cortex ○ Disorders associated with the parietal lobe Agnosias = disorders of perception Prosopagnosia = difficulty recognizing faces Astereognosis = inability to recognize common objects by feeling them Occipital lobe ○ Vision, color perception ○ Includes the primary visual cortex ○ Disorders associated with the Occipital Lobe Impaired visual recognition Blindness Brain Lateralization Hemispheres are symmetrical with respect to primary sensory and motor functions (same job, different half of the body - contralateral) Association areas have some different functions Left & Right Hemisphere Functions LEFT ○ Language ○ Logic ○ Analytical thought RIGHT ○ Spatial relations ○ Facial recognition ○ Perceiving emotion Intuitive thought ○ Musical ability Individual Differences Handedness ○ Left-handers & language: 70% on the left 15% on the right 15% both hemispheres Gender ○ Men are more lateralized for language than women Evidence of Hemispheric Asymmetry “Split-brain” patients Prosopagnosia Demo How can we study lateralization in people without split brains? Reaction time – takes slightly more time for info to go from right hemisphere to left hemisphere, compared to going only to the right hemisphere fMRI scanning to localize active brain regions Transcranial magnetic stimulation temporary brain damage!* *(no actual brain damage; makes it so that particular neurons cannot fire, temporarily; perfectly safe!) Contralateral transmission Hemispatial Neglect Most commonly a result of damage to the right parietal cortex; left visual field is affected ○ An issue of attention, not vision Lateralization Conclusions Despite the split-brain examples… The two sides of our brain are constantly working together Both hemispheres are responsible for complex human capacities Don’t believe the popular press—being ‘left- or right- brained’ is too simplistic Two Hemispheres, One Mind: Understanding Brain Lateralization 1. Brain Symmetry and Function The brain has anatomical symmetry, similar to most body organs Each hemisphere has corresponding structures, but functions are not always equally divided Early studies revealed left hemisphere dominance for language 2. Hemispheric Specialization Broca's area (left frontal lobe): Important for speech production Wernicke's area (left temporal lobe): Crucial for speech comprehension Left hemisphere: Usually dominant for language Right hemisphere: Silent but important partner in language processing 3. Corpus Callosum: The Brain's Bridge Connects the two hemispheres, allowing information sharing Supports contralateral communication between brain and body Can be severed in split-brain procedures to treat severe epilepsy 4. Contralateral Organization Right side of the body is controlled by the left hemisphere, and vice versa Applies to sensory information and motor control Visual information from each side of the visual field goes to the opposite hemisphere 5. Split-Brain Studies Roger Sperry's Nobel Prize-winning experiments Revealed independent functions of right and left hemispheres Demonstrated how each hemisphere processes information separately in split-brain patients 6. Hemispheric Differences Left hemisphere: More involved in verbal and conceptual tasks, focuses on details Right hemisphere: More engaged with perceptual and some emotional tasks, focuses on the big picture Myth debunked: People are not strictly "left-brained" or "right-brained" 7. Unified Mind The singularity of our mind and self results from the cooperation between hemispheres Both hemispheres work together in daily life for normal brain function
