Source: Textbook Chapters 1–3, Lecture Notes
Tags: paleolithic, hominin, brain evolution, mind-body problem, neurons, glia, cerebral cortex, lobes, chemistry of life, ions, phospholipids, proteins, nucleic acids, UC Berkeley, Brain-Mind Odyssey
These three chapters trace the story from early human ancestors drawing on cave walls through to the molecular building blocks of the brain. Chapter 1 introduces hominins, brain expansion, and the mind-body problem. Chapter 2 maps out the structure of the nervous system, from jellyfish nerve nets to the human cerebral cortex. Chapter 3 covers the chemistry that makes it all work: ions, polarity, lipids, proteins, carbohydrates, and nucleic acids.
Hominin
Modern humans and their recent ancestors. The lineage includes Ardipithecus (oldest, ~4.4 million years ago), Australopithecus (~3–1 million years ago), and Homo (most recent, ~1 million years ago to present).
Homo sapiens
Our species. Homo is the genus, sapiens is the species. Appeared roughly 200,000 years ago.
Mind
A collection of mental states: thoughts, feelings, perceptions. To have a mind is to have consciousness or awareness of subjective experience.
Mind-body problem
The central philosophical question: is the mind a product of the brain? How do physical processes in the brain give rise to subjective experience?
Psychoanalysis
Bringing unconscious material related to behaviour into conscious awareness, where it can be analysed and potentially changed.
Shaman
Respected healers and spiritual figures in early societies, important in Paleolithic communities.
Neuron (nerve cell)
The signalling cell of the brain. The human brain contains roughly 100 billion neurons.
Glial cell (glia)
The other main class of brain cell. More numerous than neurons. Involved in brain signalling and support functions.
Cerebrum
The outer, bumpy portion of the forebrain. In mammals, the surface is folded into gyri (bumps) and sulci (grooves).
Cerebral cortex
The main processing centre of the brain. Divided into four lobes on each hemisphere: frontal, parietal, temporal, and occipital.
Corpus callosum
A massive bundle of roughly 200 million axons connecting the left and right hemispheres.
Meninges
Three layers of tissue covering the brain surface:
Dura mater (outermost, tough)
Arachnoid (middle, spider-web-like)
Pia mater (innermost, delicate)
Cerebrospinal fluid (CSF)
Fluid found between the arachnoid and pia mater layers. Cushions and protects the brain.
Gray matter
Brain tissue composed mainly of cell bodies.
White matter
Brain tissue composed mainly of nerve fibres (myelinated axons).
Ventricles
Cavities within the brain filled with CSF.
Golgi stain (la reazione nera)
A technique using potassium dichromate and silver nitrate that produces silver chromate, staining roughly 1% of neurons. The reason only 1% stain remains unknown.
Ion
An atom that has lost or gained an electron, giving it an electric charge. Cation = positive, anion = negative.
Hydrophilic
Polar, water-loving. Includes ionic compounds, polar covalent molecules, salts, and ions.
Hydrophobic
Non-polar, water-hating. Includes oils, hydrocarbons, and other covalent non-polar molecules.
Lipophilic / lipophobic
Lipophilic = non-polar, fat-loving (same as hydrophobic). Lipophobic = polar, fat-repelling (same as hydrophilic).
Phospholipid bilayer
The boundary membrane of all cells. About 5 nanometres thick. Hydrophobic interior, hydrophilic exterior.
Protein structure (four levels)
Primary: the linear sequence of amino acids in the polypeptide chain
Secondary: local folding patterns (e.g. the alpha helix, discovered by Linus Pauling)
Tertiary: the overall 3D shape of the entire protein molecule
Quaternary: a complex of more than one polypeptide subunit (e.g. haemoglobin has four)
Nucleic acids
DNA and RNA. The double helix consists of two long chains of four nucleotides (adenine, cytosine, guanine, thymine) held together by non-covalent hydrogen bonds. In RNA, uracil replaces thymine.
Carbohydrate
Composed of carbon and hydrogen. Includes sugars (glucose, fructose) and serves as the body's main energy source.
Paleolithic humans created animal drawings in dark caves using charcoal and ochre
Chauvet Cave is a key example
Darkness may have served as an aid to inner exploration
Hominid brain size expanded rapidly over the last two million years, from ~350 cc to ~1,400 cc
Timeline of life on Earth:
Earth formed ~4.6 billion years ago
First life (prokaryotes) ~3.8 billion years ago
Eukaryotes, then multicellular organisms, then vertebrates
Sponges → arthropods → mollusks → vertebrates
Homo sapiens appeared ~200,000 years ago
Evolutionary sequence: Homo erectus → Homo neanderthalensis → Homo sapiens
Key capacity of humans: both violence (killing conspecifics) and compassion/love
René Descartes (Holland): mind-body dualism. Mind = res cogitans, body = res extensa. "I think, therefore I am."
Andreas Vesalius (1542): human anatomy expert, dissections in Bologna. Wrote De Humani Corporis Fabrica (On the Fabric of the Human Body).
Benjamin Franklin: electricity experiments (kite in a thunderstorm).
Luigi Galvani (1737): animal electricity, frog leg experiments.
A distinguished but elderly scientist who says something is possible is almost certainly right; if he says something is impossible, he is very probably wrong.
The only way to discover the limits of the possible is to venture past them into the impossible.
Any sufficiently advanced technology is indistinguishable from magic.
Sponges have no nervous system at all; jellyfish have the simplest nervous system
The basic structure of all vertebrate brains is similar: forebrain, midbrain, hindbrain, spinal cord
Forebrain: cerebrum
Midbrain: optic tectum
Hindbrain: medulla and cerebellum
The cerebrum has grown proportionally larger from ancient reptiles to modern mammals
Four lobes of the cerebral cortex (each side): frontal, temporal, parietal, occipital
Bird's-eye mnemonic (brain stem on the right): Frontal → Temporal → Parietal → Occipital
Anatomical directional terms:
Dorsal = up, ventral = bottom
Anterior = front, posterior = rear
Lateral = side, medial = middle
Sectional planes: frontal/coronal section, sagittal section (midline)
Meningitis = inflammation of the meninges
William James: pioneer in the modern scientific study of the mind. Wrote The Principles of Psychology (1890).
Camillo Golgi (Italy): developed the Golgi stain. Advocated reticular theory (the brain as a continuous network).
Santiago Ramón y Cajal (Spain): used the Golgi stain to draw detailed neuron images. Advocated neuron theory (neurons as discrete cells), which proved correct.
Giovanni Aldini: Galvani's nephew, continued electrical stimulation work.
Alessandro Volta: invented the first battery.
Chemistry = the transformation of matter. Alchemy = the transformation of matter and psyche.
"Al kamia" comes from ancient Egypt, meaning black, fertile earth land.
Human body composition by weight: 65% oxygen (#1 wet weight), 18.5% carbon (#1 dry weight), 9.5% hydrogen (#1 atomic count), 3.4% nitrogen, 1.5% calcium
Chemical bonds:
Covalent bonds: sharing of electrons
Ionic bonds: transfer of electrons
Hydrogen bonds: non-covalent, molecules loosely sticking together
Polarity = disparity of charge. Water is highly polar, which allows it to dissolve ions.
Benzene ring: intermediate between double and single bonds throughout
In a molecular diagram, any bend represents a carbon; fill remaining bonds with hydrogens (carbon always has 4 bonds)
Ethanol is hydrophilic; alcohols end in -OH
Lipids/fats: hydrocarbons, 16–24 carbons long, energy source and storage, signalling, membrane precursors
Saturated = single bonds only
Unsaturated = contains double bonds
Fatty acid = hydrocarbon chain ending in -COOH
Proteins: built from amino acids (each has a unique R group, simplest R = H)
A chain of more than ~50 amino acids = a protein
Any chain of amino acids = a polypeptide
Amine group contains nitrogen
Carbohydrates: carbon + hydrogen, main energy source (sugars, glucose, fructose)
Nucleic acids: DNA and RNA
DNA base pairs: A-T, C-G (held by hydrogen bonds)
RNA base pairs: A-U, C-G
Backbone includes a phosphate head and a carbohydrate
Antoine Lavoisier: discovered oxygen, wrote Traité Élémentaire de Chimie (first chemistry textbook).
Dmitri Mendeleev: created the periodic table of elements (1869).
Linus Pauling: Nobel Prize in Chemistry (1954) for the alpha helix; Nobel Peace Prize (1962) for opposing nuclear weapons testing.
⚠️ Know the three hominin genera and their approximate dates: Ardipithecus (~4.4 mya), Australopithecus (~3–1 mya), Homo (~1 mya to present).
⚠️ Golgi vs. Cajal: Golgi = reticular theory (continuous network), Cajal = neuron theory (discrete cells). Both used the Golgi stain. Cajal was right.
⚠️ The four lobes and their spatial arrangement are heavily tested. Use the bird's-eye mnemonic.
⚠️ Know all four levels of protein structure and be able to distinguish them (primary = sequence, secondary = local folding, tertiary = 3D shape, quaternary = multiple subunits).
⚠️ Hydrophilic vs. hydrophobic and the phospholipid bilayer orientation (hydrophilic exterior, hydrophobic interior) come up frequently.
⚠️ DNA base pairing (A-T, C-G) vs. RNA (A-U, C-G). Strands held together by hydrogen bonds (non-covalent).
⚠️ Mind-body problem: be able to define it clearly and reference Descartes' dualism.
Q: What are the three hominin genera discussed in the course, and when did each exist?
A: Ardipithecus (oldest, ~4.4 million years ago), Australopithecus (~3–1 million years ago), and Homo (~1 million years ago to present).
Q: What is the mind-body problem?
A: The question of whether the mind is a product of the brain, and how physical neural processes give rise to subjective conscious experience.
Q: What are gyri and sulci?
A: Gyri are the bumps (ridges) on the surface of the cerebral cortex; sulci are the grooves between them.
Q: Name the three layers of the meninges from outermost to innermost.
A: Dura mater (tough), arachnoid (web-like), pia mater (delicate). CSF sits between the arachnoid and pia layers.
Q: What is the difference between gray matter and white matter?
A: Gray matter is composed primarily of neuronal cell bodies. White matter is composed primarily of myelinated nerve fibres (axons).
Q: What distinguishes the Golgi stain, and what is unusual about it?
A: It uses potassium dichromate and silver nitrate to produce silver chromate. Only about 1% of neurons are stained, and the reason is still unknown.
Q: What is the difference between hydrophilic and hydrophobic molecules?
A: Hydrophilic molecules are polar and dissolve in water (e.g. ions, salts). Hydrophobic molecules are non-polar and repel water (e.g. oils, hydrocarbons).
Q: Name the four levels of protein structure.
A: Primary (amino acid sequence), secondary (local folding, e.g. alpha helix), tertiary (overall 3D shape), quaternary (multiple polypeptide subunits, e.g. haemoglobin).
Q: What are the four nucleotide bases in DNA, and how do they pair?
A: Adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). In RNA, uracil (U) replaces thymine.
Q: What is the corpus callosum?
A: A massive fibre bundle of approximately 200 million axons connecting the two cerebral hemispheres.
Paleolithic cave art, Chauvet Cave, hominin, Homo sapiens, Homo erectus, brain evolution, cranial capacity, mind-body problem, dualism, res cogitans, res extensa, Descartes, Vesalius, Galvani, Benjamin Franklin, Clarke's three laws, William James, Principles of Psychology, neuron, glia, cerebrum, cerebral cortex, frontal lobe, parietal lobe, temporal lobe, occipital lobe, gyrus, sulcus, corpus callosum, meninges, dura mater, arachnoid, pia mater, CSF, cerebrospinal fluid, gray matter, white matter, ventricles, Golgi stain, Camillo Golgi, Santiago Ramón y Cajal, reticular theory, neuron theory, ion, cation, anion, hydrophilic, hydrophobic, lipophilic, lipophobic, phospholipid bilayer, polarity, hydrogen bond, covalent bond, ionic bond, lipid, fatty acid, protein structure, alpha helix, amino acid, polypeptide, carbohydrate, nucleic acid, DNA, RNA, Mendeleev, periodic table, Lavoisier, Linus Pauling