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Integrating Mind and Brain: Neuroscience Unification

Explore the connection between mind and brain, neuroscientific perspectives, historical theories, neuronal discoveries, localization debates, and current views on brain functions and language circuits.

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Integrating Mind and Brain: Neuroscience Unification

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  1. Brain and Behavior Chapter 1

  2. Mind, Brain and Behavior • Neuroscientists want to unify the science of the mind with the science of the brain. • Actions of the brain underlie all behavior. • What we call mind is a range of functions carried out by the brain. • Neural science explains behavior in terms of brain activities. • Where does psychology fit?

  3. Understanding by Analogy • Metaphors have always been drawn from discoveries in the physical world: fluid mechanics, windmills, man as machine. • Discarded theories: • Fluid in ventricles, flow of humors (Galen) • Body as machine explained by mechanics • Nerves as hollow tubes full of gas or fluid • Vibrating “aetherial Medium”

  4. Two Alternative Views • Cellular connectionism: • Individual neurons are the signaling elements of the nervous system, arranged in functional groups • Supported by empirical observations of Ramon y Cajal, Wernicke, Jackson, Sherrington. • The aggregate field view: • All regions of the brain participate in all mental functions. • Mind is NOT completely biological.

  5. Localization vs Distribution • Are specific functions carried out in specific regions of the brain? • Are functions an emergent property of brain activity as a whole? • Today’s neuroscience still debates this. • The answers appear somewhere between the two extremes.

  6. The Discovery of the Neuron • Golgi developed a silver staining method that revealed the cell body and projections of the neuron. • Ramon y Cajal used the technique to show that neurons do not quite touch. • Neurons are a network of separate (discrete) cells that communicate. • Galvani showed that the signaling is electric.

  7. The Localization Debate • Gall – the brain consists of 35+ organs corresponding to mental faculties. • Observable through bumps on the head. • Phrenology – anatomical basis for personology • Flourens – “…all perceptions, all volitions occupy the same seat…” • Aggregate field view • A reaction against strict materialism (mind not completely biological).

  8. The Discovery of Localization • Imaging techniques that show the brain in action confirm that certain functions are carried out in specific areas of the brain. • This was difficult to see early on because of parallel processing • Each function is subserved by more than one neural pathway. • When one pathway is damaged, others may compensate, making localization harder to see.

  9. Organizational Principles • Two hemispheres – left, right • Each with four distinct lobes: • Frontal – thinking, planning, control of movement • Parietal – tactile sensation, body image, space • Occipital – vision • Temporal – hearing, learning and memory, emotion • Each lobe has folds: • Gyri (gyrus) – crests (flat areas) • Sulci (sulcus) – grooves (areas folded in)

  10. Organization (Cont.) • Contralateral control: • The left hemisphere controls the right side of the body. • The right hemisphere controls the left side of the body. • Sensory information from one side of the body is interpreted by the opposite brain hemisphere. • Some brain functions are localized to a hemisphere.

  11. Localization of Language • Aphasia – a difficulty of language caused by brain injury (such as with stroke). • Broca – described patients who can understand language but not speak. • Results from damage to Broca’s area. • Wernicke – described patients who can speak but not understand language. • Results from damage to Wernicke’s area.

  12. A Language Circuit • Wernicke’s areas and Broca’s areas are part of a connected circuit for receiving and producing language. • Wernicke predicted conduction aphasia – a disorder produced by breaking the connection between the two regions. • Results in paraphasia – omitting and substituting parts of speech. Also, inability to repeat phrases.

  13. Brodmann Areas • Different areas of the brain with different functions have different kinds of neurons. • Brodmann mapped the areas based on the kinds of cells found: • Cytoarchitectonic method • 52 functionally distinct areas identified by number.

  14. Support for the Field View • Lashley found that the greater the lesions, the greater the impairment in functioning. • No matter where lesions were made, learning was impaired. • Mass action -- brain mass, not specific regions was most important to functioning. • Maze learning involves multiple functions, so it is unsuitable for studying localization.

  15. The Current View • Functions consist of multiple processes that occur in specific areas of the brain. • Imaging studies reveal the different processes, called elementary operations. • Processing is both serial and parallel. • Even the simplest mental activity requires coordination of processes in multiple areas of the brain. • Such processing appears introspectively seamless.

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