OGNITIVE SCIENCE 17 What’s A Brain? Part 1 Jaime A. Pineda, Ph.D. Meshberger, JAMA 264:1837-1841
Feb 09, 2016
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 MemoryAttentionLanguagePlanningCreativityAwarenessConsciousness
Classical physics
BODY-MIND RELATIONSHIP(STRUCTURE-FUNCTION)
• BODY/BRAIN • MIND MemoryAttentionLanguagePlanningCreativityAwarenessConsciousness
Self-directed neural plasticity?Quantum physics and the causal efficacy of thought?
Is Reality a “Construction”?
Stimulus Selection InterpretationBottom-up processing Top-down processing
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
Bell –Magendi Law 1811
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
Modern Phrenology
Unilateral Neglect
- lesions to right parietal cortex - failure to notice things on the left side- failure to remember things on the left side
Split Brain
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)
Bipolarcells
axon
dendrites
terminalbouton
Variety of Multipolar NeuronsDiffer in terms of:
• genes expressed• chemicals • shape• arborization • connectivity patterns…
Structure function
104 connections per neuron
1014 total interconnections(one hundred trillion)
Dendritic Spines
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)
Einstein’s Brain
Greater number ofneuroglia
Larger inferior parietalcortex