COGNITIVE SCIENCE 17 What’s A Brain? Part 1 Jaime A. Pineda, Ph.D. Meshberger, JAMA 264:1837-1841.
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Transcript of COGNITIVE SCIENCE 17 What’s A Brain? Part 1 Jaime A. Pineda, Ph.D. Meshberger, JAMA 264:1837-1841.
The Fundamental Circularity of Being
“The world is inseparable from the subject, but from a subject which is nothing but a projection of the world,and the subject is inseparable from the world, but froma world which the subject itself projects.”
Merleau-Ponty (1906-1961)
Mind-Body Question
• Dualism– Belief in the dual
nature of reality
– Mind and body are separate
– Body is made of ordinary matter
– Mind is not
• Monism– Belief that everything
in the universe consists of matter and energy
– Mind is a phenomenon produced by the workings of the nervous system
The goal of Cognitive Neuroscience is to provide andexplain the mapping between
brain and mind
Or put another way, between
structure and function
Is there an identity such that brain=mind?Is it more of a correspondence?Just what is the relationship?
BODY-MIND RELATIONSHIP(STRUCTURE-FUNCTION)
• BODY/BRAIN • MIND
Memory
Attention
Language
Planning
Creativity
Awareness
Consciousness
Classical physics
BODY-MIND RELATIONSHIP(STRUCTURE-FUNCTION)
• BODY/BRAIN • MIND
Memory
Attention
Language
Planning
Creativity
Awareness
Consciousness
Self-directed neural plasticity?Quantum physics and the causal efficacy of thought?
Rene Descartes (1596-1650)
De Homine – 1662
Mechanistic view of brain
Pineal gland – gateway to soul
“…ingenuity and originality were unfortunately based onpure speculation and incorrectanatomical observations.”
“I think therefore I am”
Luigi Galvani
(1737-1798)
Professor of Obstetrics
Moves frog leg with static electricity
Detects electricity in the nerves offrogs
Paul Broca(1824-1880)
Anthropologist and anatomist
Paris educated MD pathologist
“Tan” aphasic patient died inApril 1861
“Nous parlons avez l’hemispheregauche”
(We speak with the left hemisphere)
Franz Joseph Gall (1758-1828)
Analysis of the shapes and lumps of the skull would reveal a person’s personality and intellect.
Phrenology
Unilateral Neglect
- lesions to right parietal cortex - failure to notice things on the left side- failure to remember things on the left side
Neurons• Functional units of
communication• 100 billion + a few million• Independent units (Neuron
Doctrine)• Bioelectrically driven
(Functional polarity)• Categorized in terms of
Function (sensory, motor); Location (cortical, spinal); NT (cholinergic);
Shape (pyramidal, stellate)
Variety of Multipolar Neurons
Differ in terms of:
• genes expressed• chemicals • shape• arborization • connectivity patterns…
Structure function
104 connections per neuron
1014 total interconnections(one hundred trillion)
Myelination
• Insulates axon
• Speeds up conduction without increasing diameter of axon
• Saves energy
Nodes of Ranvier
Neuroglial Cells
• Physical and metabolic support
• 90% of cells in brain
• Four types– Astrocytes (maintenance/support)– Oligodendrocytes (myelin)– Ependymal (line ventricles)– Microglia (macrophages)