COGNITIVE SCIENCE 17 What’s A Brain? Part 1 Jaime A. Pineda, Ph.D. Meshberger, JAMA 264:

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 from a world which the subject itself projects.” Merleau-Ponty ( )

Mind-Body Question Dualism –B–Belief in the dual nature of reality –M–Mind and body are separate –B–Body is made of ordinary matter –M–Mind is not Monism –B–Belief that everything in the universe consists of matter and energy –M–Mind is a phenomenon produced by the workings of the nervous system

The goal of Cognitive Neuroscience is to provide and explain 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/BRAINMIND Memory Attention Language Planning Creativity Awareness Consciousness Classical physics

BODY-MIND RELATIONSHIP (STRUCTURE-FUNCTION) BODY/BRAINMIND Memory Attention Language Planning Creativity Awareness Consciousness Self-directed neural plasticity? Quantum physics and the causal efficacy of thought?

Is Reality a “Construction”?

Rene Descartes ( ) De Homine – 1662 Mechanistic view of brain Pineal gland – gateway to soul “…ingenuity and originality were unfortunately based on pure speculation and incorrect anatomical observations.” “I think therefore I am”

Luigi Galvani ( ) Professor of Obstetrics Moves frog leg with static electricity Detects electricity in the nerves of frogs

Bell –Magendi Law 1811

Paul Broca ( ) Anthropologist and anatomist Paris educated MD pathologist “Tan” aphasic patient died in April 1861 “Nous parlons avez l’hemisphere gauche” ( We speak with the left hemisphere )

Franz Joseph Gall ( ) 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 ailure 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)

Bipolar cells axon dendrites terminal bouton

Variety of Multipolar Neurons Differ in terms of: genes expressed chemicals shape arborization connectivity patterns… Structure  function 10 4 connections per neuron 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 of neuroglia Larger inferior parietal cortex