3. Parallelism: mind & brain are 2 aspects of the same reality, every event in the mind has a corresponding event in the brain 4. Isomorphism: experience and corresponding brain pattern share the same pattern in all their structural characteristics o Necker cube: Same external stimulus can produce different internal experiences o There must be a corresponding change in underlying brain processes Animal Models (method): - invasive neuroimaging - lesions - can investigate brain mechanisms through lesions, single and multiple cell unit recording - Weakness: not a full understanding of the human brain, cannot generalize between species Behavioural Studies: - Healthy human subjects - Weakness: cannot draw specific links between behavior and brain mechanisms The study of brain injuries: after injury, what function suffers? - Helps map functions onto brain - Broca’s Aphasia: damage to Broca’s area causes defecit in the ability to produce speech o Comprehension is okay o Production is impaired - Wernicke’s aphasia: damage to wernicke’s area – deficit in comprehending speech o Comprehension is impaired o Production is okay but incoherent - However, aphasia clusters of symptoms; language brain areas difficult to pinpoint because other regions are also involved Surgical Interventions: Sperry: - interhemispheric transfer – severed optical chiasm and corpus callosum in cats o Animal behaved as if it had 2 brains o Left hemisphere: analytical tasks o Right hemisphere: holistic tasks - Consciousness is an emergent property: cannot be reducible or a property of a particular brain structure - Consciousness has emergent causation: it can influence lower-level functions - The mind is supervenient: mental states may simultaneously influence neuronal events and be influenced by them Brain stains: special stains to see brain tissues (19 th century) - They believed it was a continuous, complex pathway for conducting signals without interruption - Golgi stains – Camilo Golgi 4
- Ramon y Cajal refined the technique – used newborn animal brains Event-Related Potentials: an electrical signal emitted by the brain after the onset of a stimulus EEG: electroencephalography - Disc electrode on scale that pic up signals from groups of neurons that fire together Positron Emission Tomography (PET): measures blood flow in the brain - Active areas use more oxygen = more blood flow - Participants injected with low-dose radioactive tracer o However, there are limits to amount of radiation to which a participant may be exposed – so limits of how much info can be gathered from each patient fMRI: large magnetic field that takes an image of brain activity - Detects flow of oxygenated blood to various parts of the brain Connectionist Models: - Brain has a vast number of neuronal networks - Model of these networks can show how cognitive processes work - DTI (diffusion tensor imaging): MRI based technique that makes it possible to visualize the white-matter tracts within the brain - 2 basic ideas 1. Information can be broken down into elementary units (neurons) 2.
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