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COGNITIVE NEUROSCIENCE SUMMARY
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CHAPTER 1: A BRIEF HISTORY OF COGNITIVE NEUROSCIENCE
1.1 A HISTORICAL PERSPECTIVE
The field of cognitive neuroscience got its name in the 1970s stemming from the terms cognition, the
process of knowing (awareness, perception, reasoning) and neuroscience, the study of how the nervous
system is organised and functions.
Evolution of the human brain and its function is built through a process of evolution, by natural selection,
through a long process of trial and error. The evolutionary perspective has to be kept in mind: Why might this
behavior have been selected for? How could it have promoted survival and reproduction? WWHGD? (What would
a hunter-gatherer do?).
As civilization developed, people thought of the natural world just as they thought of themselves: having
thoughts, desires, and emotions. Ancient Greeks were the theoretical leap, viewing humans as separate from
the world we live in. They presumed that a single order underlies the chaos of our perceptions and,
furthermore, that we are able to comprehend that order.
Thales, a pre-Socratic philosopher, rejected supernatural explanations of phenomena and proclaimed that
every event had a natural cause. They did not have the methodology to systematically explore the brain and
the thoughts it produces (the mind) through experimentation. Thales was a monist, meaning he thought that
the brain and mind were one and the same.
Descartes, on the other hand, was a dualist. He believed that the body (including the brain) had material
properties and worked like a machine, whereas the mind was nonmaterial and thus did not follow the laws of
nature. He thought that the two interacted, mind and body could influence each other through “the passions”.
The interaction was thought to happen in a single brain structure, the pineal gland, which was not found
bilaterally.
Cognitive neuroscience today is monistic: the conscious mind is a product of the brain’s physical activity and
not separate from it. Evidence can be found in the study of brain lesions. The scientific method is used to
understand how the biological systems work, by observing, forming a hypothesis, designing and performing
experiments related to the hypothesis and finally drawing conclusions.
1.2 THE BRAIN STORY
Modern research in cognitive neuroscience is mostly concerned with whether the mind is enabled by the
brain working as a whole or as a sum of its specialized independent parts.
T. Willis stated that isolated brain damage (biology) could affect behavior (psychology), but his insights
slipped from view.
F.J. Gall was convinced that the brain was the organ of the mind and innate attributes were localized in
specific regions of the cortex. There (35 or more) specific regions were associated with basic cognitive
functions such as language and color perception to more ephemeral capacities such as affection and a moral
sense.
J. Spurzheim along with Gall hypothesised that the more frequently you use an innate attribute the part of
the brain associated with the function would grow, leading to bumps in the skull. Gall formed the technique of
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anatomical personology, where the careful analysis of the skull could describe the personality of the person.
Spurzheim formed the field of phrenology.
Flourens did research on animals (pigeons, rabbits) destroying parts of their brains and observing what
happens. He showed that certain parts of the brain were responsible for certain functions. He developed the
idea that the whole brain participates in behavior, later named aggregate field theory. With this idea, the
theory of localized brain functions (localizationism) fell out of favor.
J. Hughlings Jackson brought back the notion of localizationism by observing epileptic patients’ seizures,
leading him to propose a topographic organization of the cortex: A map of the body represented across the
cortical area, representing different parts of the body (foot, arm). He was also the first to observe that lesions
on the right side of the brain affect visuospatial processes more than do lesions on the left side.
Broca with observing patient Tan (he could understand language but only produce the word tan when
speaking), supposed the idea of localizationism, Tan had a syphilitic lesion in his left -hemisphere inferior
frontal lobe. The specific area of language that was impaired by the lesion was called Broca’s area.
Wernicke reported on a stroke victim who (unlike Broca’s patient) could talk quite freely but made little
sense when he spoke and also did not understand spoken language. The lesion was in a posterior region of
the left hemisphere (where temporal and parietal lobes meet), which is now referred to as Wernicke’s area.
Gustav Fritsch and Eduard Hitzig conducted animal research, electrically stimulating parts of dogs’ brains,
supporting their ideas about the importance of local regions.
Brodmann analyzed the cellular organization of the cortex, characterizing 52 distinct regions in the brain,
publishing a cortical map. He divided the parts based on cytoarchitectonics (cellular architecture) meaning
how cells differ between brain regions. Investigators discovered that various cytoarchitectonically described
brain areas do indeed represent functionally distinct brain regions.
Golgi developed one of the most famous cell stains in the history of the world: the silver method for staining
neurons—la reazione nera, “the black reaction”, which impregnated individual
neurons with silver chromate. This stain permits visualization of individual neurons in their entirety. Golgi
had believed that the whole brain was a syncytium, a continuous mass of tissue that shares a common
cytoplasm.
Santiago Ramón y Cajal known as the father of modern neuroscience, was the first to identify the neuron
doctrine, the concept that the nervous system is made up of individual cells. He also recognised the
transmission of electrical information flowing in one direction (from dendrites to axons).
20th century approaches suggest that a combination of the localizationist and holistic views is possible. The
knowledge of the parts (neurons and brain structures) must be understood in conjunction with the whole
(what the parts make when they come together).
1.3 THE PSYCHOLOGICAL STORY
Rationalism supports that all knowledge could be gained through the use of reaction alone, as they would
determine true beliefs and would reject beliefs that, although perhaps comforting, were unsupportable and
even superstitious, through the process of thinking. Rationalism should not be mistaken for logical thinking
because rationalism is concerned with personal mental states (happiness/public good) which are issues each
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person weighs differently whereas logical thinking relies simply on inductive reasoning (statistics,
probabilities).
Empiricism is the idea that all knowledge comes from sensory experience, that the brain begins life, as a
blank slate. Direct sensory experience produces simple ideas and concepts and when those are associated
together they form complex ideas that are then incorporated into one’s knowledge system. Hobbes, Locke and
Hume, all emphasized the role of experience.
Associationism supports that the aggregate of a person’s experience determined the course of mental
development. Ebbinghaus was one of the first to understand that mental processes that are more internal,
such as memory, also could be measured.
Behaviorism was formed by the ideas of Watson that psychology could be objective only if it was based on
observable behavior, rejecting the Ebbinghaus’ methods of measuring mental processes. This became a very
popular field and dominated over the idea of measuring mental states that are not observable in behavior.
Montreal became a hot spot for new ideas on how biology shapes cognition and behavior. The Montreal
procedure was invented, for treating epilepsy, surgically destroying neurons in the brain that produce
seizures. Observations led to the creation of the map of sensory and motor cortices in the brain.
On September 11, 1956, after a year of great development and theory shifting, Miller realized that, although
behaviorism had important theories to offer, it could not explain all learning.
The end of the dominance of behaviorism came with several technological advancements (Signal detection
and computer techniques). Artificial Intelligence shed light on how the brain’s computational activities were
similar to a massively parallel computer. Thus the field of cognitive psychology was born, using psychological
testing methods and implications.
The field of cognitive neuroscience was born in 1970 when Goldman-Rakic, but together a multidisciplinary
team of people working in biochemistry, anatomy, electrophysiology, pharmacology, and behavior.
1.4 THE INSTRUMENTS OF NEUROSCIENCE
The technological advancements provided tools to study how the brain works.
Electroencephalography was the first non-invasive method to study the brain. Einthoven was able to make
photographic recordings of the electrical activity of the cerebral cortex, using a galvanometer. He named this
type of recording electroencephalography, this remained the sole technique for noninvasive brain study for a
number of years.
Measuring Blood Flow in the Brain: Mosso recorded pulsations as blood flowed around and through the
cortex in these patients and noticed that the pulsations of the brain increased locally during mental activities
such as mathematical calculations. He inferred that blood flow followed function.
Computerized Axial Tomography: Next to blood flow there was also interest in having good anatomical
images that could pinpoint the location of tumors for other developments in instrumentation. Oldendorf
wrote an article providing the first description of the basic concept that was later used for CT.
Positron Emission Tomography and Radioactive Tracers: While the CT/CAT was great for revealing
anatomical detail, it revealed little about function. CAT was used as a basis for developing positron emission
tomography (PET), a noninvasive sectioning technique that could provide information about function. The
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development of PET goes hand in hand with the development of radioactive isotopes, or 'tracers', that it
employs. These came from the hand of Curie and her husband. Radioactive forms of oxygen, nitrogen and
carbon could be produced and injected into the blood circulation and would become incorporated into
biologically active molecules. These molecules would concentrate in an organ, where the radioactivity would
begin to decay. The concentration of the tracers would then be measured over time.
Magnetic Resonance Imaging: MRI is based on the principle of nuclear magnetic resonance, which was first
described by Rabi. The protons in water molecules line up like little bar magnets. If the equilibrium of these
protons is disturbed, then a measurable voltage is induced in a receiver coil. The voltage changes over time as
a function of the proton's environment. Analysis of the voltages can yield information about the examined
tissue.
Functional Magnetic Resonance Imaging: An increase in oxygen delivery permitted more glucose to be
metabolized, and thus more energy would be available for performing the task. Fox and Raichle found that
although functional activity induced increases in blood flow, there was no corresponding increase in oxygen
consumption. Functional MRI does not use ionizing radiation, it combines beautifully detailed images of the
body with physiology related to brain function, and it is sensitive.
