Computational Neuroscience
Lecture 1 : History of Neuroscience
Prashant Joshi
joshi@fias.uni-frankfurt.de
Summer Semester - 2010
Origins of Neuroscience
You probably know that:
“The nervous system (brain, spinal cord and
nerves) is crucial for life and enables you to
sense, move, and think”
How did this view arise?
We've been curious for quite a while
Food for thought:
What were these surgeons trying
to accomplish?
~ 5000 years ago, Egyptians were
aware of symptoms of brain
damage
The Brain According to Aristotle
The seat of the soul and the control of voluntary
movement - in fact, of nervous functions in
general, - are to be sought in the heart.
The brain is an organ of minor importance.
- Aristotle, De motu animalium, 4th Century, B.C.
Aristotle believed that brain acts as a radiator for cooling of blood
overheated by a seething heart.
Hippocrates got it right:
Function from structure
From Ancient Greece to Roman Empire
Galen's Hypothesis:
1. Cerebrum receives sensations,
Cerebellum controls movements
2. The ventricles hypothesis
th
Views from Renaissance to 19 Century
1)The fluid-mechanical (ventricle) theory persisted
2)One of the chief advocate was Descartes
3)Blame him for the “mind-brain problem”
Breaking Away From Galen's View
Describing the function of white and gray matter
 Description of the gross anatomy in detail
 Distinction Between CNS and PNS

Observation of “bumps” and grooves” Start of Cerebral Localization
Bumps are called “gyri” and grooves “fissures”
● Allows parceling of cerebrum into lobes
● Start of Cerebral Localization
●
th
Views at the end of 18 Century
Injury to the brain can disrupt sensations,
movement and thought and can cause death
The brain communicates with body via nerves
The brain has different identifiable parts which
probably have different functions
The brain operates like a machine and follows the
laws of nature
th
19 Century – End of ventricle theory
1751 – Benjamin Franklin published “Experiments
and Observations on Electricity”
New understanding of electrical phenomenon
Galvani & du Bois-Reymond (1800s)
1)Electrical stimulation of nerves twitches muscles
2) Brain itself can generate electricity
Establishing pathways for sensory
and motor information
Question: Whether signals to the muscles causing
movement use the same wires as those that
register sensations from the skin?
Case for Bidirectional Hypothesis (wrong): Cut a
nerve, loose sensation and movement
Case for Unidirectional Hypothesis (1810, Bell &
Magendie): Cutting, ventral roots causes
paralysis, dorsal roots carry sensory information
Localization of Specific Functions to
Different Brain Regions
Gall, 1809 – Bumps on skull correlate with gyri Phrenology
The Fall of Phrenology
Flourens, 1823 - made two important contributions:
1. Showed experimentally (using ablation) that cerebrum
(sensation & perception) and cerebellum (movement)
perform different functions
2. Against Phrenology: Particular traits are not isolated to
regions ascribed by phrenology, and that the bumps are
not correlated with gyri
The beginning of localization
Had a patient “Tan” who could understand language but
couldn't speak
He discovered a lesion in the left frontal lobe, and concluded
that this region was responsible for production of speech
The Evolution Theory of Nervous Systems
Darwin introduced the theory of evolution
Evolution led to development of traits that distinguish species today
Rationale behind animal experiments: The idea that the nervous
system of different species evolved from common ancestors and
may have common mechanisms
Neuroscience Today – Levels of Analysis
Molecular Neuroscience – examines the biology of the
nervous system with molecular biology, molecular genetics,
protein chemistry and related methodologies
Cellular Neuroscience - How all these molecules work
together to give the neuron its special properties?
Systems Neuroscience - study how different neural circuits
analyze sensory information, form perceptions of the external
world, make decisions, and execute movements
Behavioral Neuroscience - How do neural systems work
together to produce integrated behaviors?
Types of Neuroscientists
The Advent of Modern Neuroscience
Start of study of structure of brain cells
Problems:
1) Small Size ~ 0.01-0.05 mm dia – Solved with a
microscope
2) To observe under microscope, one needs thin slices
(made using microtome), and to make slices, the tissue
has to be hardened (using formaldyhyde)
3) To selectively color tissue, one needs a special
chemical called stain
The Golgi Stain (Silver Chromate), 1873
Ability to view a small percentage of neurons in
their entirety
Clearly visible soma, axon and dendrites
Cajal's Contribution – The Neuron Doctrine
Used Golgi stain to work out the circuitry of many regions of the brain
Golgi and Cajal had opposite views about neurons
Neuron Doctrine – Neurons adhere to the cell theory
The Rise of Computational Neuroscience
Warren McCulloch and Walter Pitts proposed the
first model of an artificial neuron