Overview
This lecture covers the historical and current scientific debates about the brain and mind, brain structure and function, neuroimaging techniques, brain plasticity, types of brain injury, and neurodegenerative disease.
Brain vs Heart Debate & Mind-Body Problem
- The brain vs heart debate questioned whether thoughts and behaviors originate from the brain or heart.
- Heart hypothesis: the heart is the source of thoughts, feelings, and behaviors.
- Brain hypothesis: the brain is responsible for mental processes.
- Mind-body problem: asks if the mind is separate from the body or if they are one entity.
- Monism believes mind and body are unified; dualism believes they are separate.
- Phrenology claimed personality could be determined by skull shape, but is pseudoscience.
- Franz Gall’s principles: faculties depend on brain structure, brain has specialized regions, skull shape reflects brain.
Methods to Study Brain Function
- Brain ablation and lesioning involve removing or damaging brain regions to study their function.
- Split-brain research examines effects of severed corpus callosum on brain function.
- Corpus callosum connects the left and right hemispheres; cerebral hemispheres are the brain’s two halves.
- Hemispheric specialization: left hemisphere controls language/right body, right hemisphere controls left body.
Neuroimaging Techniques
- Structural techniques (CT, MRI) show brain structure.
- Functional techniques (PET, fMRI) measure brain activity.
- CT: uses x-rays and contrast dye for 2D/3D brain images.
- MRI: uses magnets/radio fields for detailed brain images.
- PET: tracks radioactive substances to show active brain regions.
- fMRI: detects blood flow changes to measure brain activity in real time.
Brain Structure and Functions
- The hindbrain controls vital functions (sleep, autonomic functions, movement) and includes pons, medulla, cerebellum.
- The midbrain relays sensory messages and regulates alertness.
- The forebrain handles complex processing, voluntary movement, and homeostasis; includes cerebrum, thalamus, hypothalamus.
Cerebral Cortex and Lobes
- Cerebral cortex oversees higher order thinking, memory, emotion, and language.
- Frontal lobe: planning, judgment, personality, speech (Broca’s area), voluntary movement (primary motor cortex).
- Parietal lobe: spatial reasoning, sensation, pain, touch (primary somatosensory cortex).
- Occipital lobe: visual processing.
- Temporal lobe: memory, recognition, language comprehension (Wernicke’s area), auditory processing.
Neuroplasticity and Brain Recovery
- Neuroplasticity: brain's ability to change structure/function in response to experience.
- Developmental plasticity: changes from aging/maturation.
- Synaptogenesis: formation of new synaptic connections.
- Synaptic pruning: elimination of unused synapses.
- Myelination: development of myelin around axons.
- Adaptive plasticity: brain’s recovery after injury via sprouting and rerouting.
- Brain function is sustained by mental stimulation, diet, physical activity, and social support.
Brain Injury and Its Impacts
- Acquired brain injury occurs after birth; can be traumatic (external force) or non-traumatic (internal factors).
- Biological impacts: fatigue, sensory issues, hormonal imbalance.
- Psychological impacts: emotional and memory issues, behavior change.
- Social impacts: difficulties in relationships and social interaction.
Neurodegenerative Diseases & CTE
- CTE is caused by repeated mild brain injuries and leads to tau protein buildup and brain cell death.
- Symptoms of CTE include cognitive decline, mood disorders, memory loss, impulsivity, aggression, and dementia.
- CTE diagnosed after death via brain examination for tau proteins and tangles.
- Prevention of neurodegenerative diseases focuses on avoiding repeated head trauma.
Key Terms & Definitions
- Monism — belief that mind and body are a single entity.
- Dualism — belief that mind and body are separate.
- Phrenology — pseudoscience linking skull shape to personality.
- Neuroplasticity — brain’s ability to change and adapt.
- Synaptogenesis — creation of new synapses.
- Synaptic pruning — removal of unused synapses.
- Hemisphere specialization — specific functions assigned to left/right brain hemispheres.
- CT, MRI, PET, fMRI — major neuroimaging techniques for brain structure and function.
- CTE (Chronic Traumatic Encephalopathy) — brain disease from repeated minor injuries.
Action Items / Next Steps
- Review and memorize brain structure, lobes, and their functions.
- Study the differences and uses of neuroimaging techniques.
- Prepare for discussion on neuroplasticity and its role in recovery.
- Complete any assigned readings related to brain injuries and neurodegenerative diseases.