Neuroscience is the scientific study of the
nervous system. Such studies span the
structure,
function,
evolutionary history,
development,
genetics,
biochemistry,
physiology,
pharmacology,
informatics,
computational neuroscience and
pathology of the nervous system.
The
International Brain
Research Organization was founded in 1960, the
European Brain and
Behaviour Society in 1968, and the
Society for Neuroscience in 1969,
but the study of the
brain dates at least to
ancient Egypt. Traditionally,
neuroscience has been seen as a branch of the
biological sciences. Recently, however,
there has been a surge of interest from many allied disciplines,
including
cognitive and
neuro-psychology,
computer science,
statistics,
physics,
philosophy, and
medicine. The scope of neuroscience has now
broadened to include any systematic, scientific, experimental or
theoretical investigation of the central and
peripheral nervous system of
biological organisms. The empirical methodologies employed by
neuroscientists have been enormously
expanded, from biochemical and genetic analyses of the dynamics of
individual
nerve cells and their molecular
constituents to
imaging of perceptual
and motor tasks in the brain. Recent theoretical advances in
neuroscience have been aided by the use of computational
modeling.
Overview
The
scientific study of the
nervous systems underwent a
significant increase in the second half of the twentieth century,
principally due to revolutions in
molecular biology,
electrophysiology, and
computational neuroscience. It
has become possible to understand, in much detail, the complex
processes occurring within a single
neuron.
However, how networks of neurons produce intellectual behavior,
cognition, emotion, and physiological responses is still poorly
understood.
The nervous system is composed of a network of
neurons and other supportive cells (such as
glial cells). Neurons form functional circuits,
each responsible for specific tasks to the behaviors at the
organism level. Thus, neuroscience can be studied at many different
levels, ranging from molecular level to cellular level to systems
level to cognitive level.
At the molecular level, the basic questions addressed in
molecular neuroscience include the
mechanisms by which neurons express and respond to molecular
signals and how
axons form complex
connectivity patterns. At this level, tools from
molecular biology and
genetics are used to understand how neurons develop
and die, and how genetic changes affect biological functions. The
morphology, molecular identity
and physiological characteristics of neurons and how they relate to
different types of behavior are also of considerable interest. (The
ways in which neurons and their connections are modified by
experience are addressed at the physiological and cognitive
levels.)
At the cellular level, the fundamental questions addressed in
cellular neuroscience are the
mechanisms of how neurons process signals physiologically and
electrochemically. They address how signals are processed by the
dendrites,
soma and
axons, and how
neurotransmitters and electrical
signals are used to process signals in a neuron. Another major area
of neuroscience is directed at investigations of the development of
the nervous system. These questions of
neural development include the
patterning and regionalization of the
nervous system, neural
stem cells,
differentiation of neurons
and glia,
neuronal
migration, axonal and dendritic development,
trophic interactions, and
synapse formation.
At the systems level, the questions addressed in
systems neuroscience include how the
circuits are formed and used anatomically and physiologically to
produce the physiological functions, such as
reflexes,
sensory
integration,
motor
coordination,
circadian
rhythms,
emotional response,
learning and
memory. In other
words, they address how these neural circuits function and the
mechanisms through which behaviors are generated. For example,
systems level analysis addresses questions concerning specific
sensory and motor modalities: how does
vision work? How do
songbirds learn new songs and
bats localize with
ultrasound? How does the
somatosensory system process tactile
information? The related field of
neuroethology, in particular, addresses the
complex question of how neural substrates underlies specific
animal behavior.
At the cognitive level,
cognitive
neuroscience addresses the questions of how
psychological/cognitive functions are produced by the neural
circuitry. The emergence of powerful new measurement techniques
such as
neuroimaging (e. g.,
fMRI,
PET,
SPECT),
electrophysiology and
human genetic analysis combined with
sophisticated
experimental
techniques from cognitive psychology allows neuroscientists and
psychologists to address abstract questions such as how
human cognition and emotion are mapped to
specific neural circuitries.
Neuroscience Education
engages students from pre-Kindergarten through College in the study
of neuroscience and provides training for Graduate students and
Post-Doctoral fellows. Research in this area tests hypotheses
pertaining to best practices in teaching and learning neuroscience
concepts and can be funded through RO1 and R25 mechanism from NIH,
major grants from NSF, and other federal and private granting
mechanisms.
Neuroscience
Literacy includes efforts to raise knowledge and awareness
about the nervous system and behavior among the general public, as
well as public officials, policy makers, and legislators. Major
world wide efforts in both Neuroscience Education and Neuroscience
Literacy include
Brain Awareness
Week cosponsored by the
Society for Neuroscience and
Dana Alliance for
Brain Initiatives, as well as the
International Brain Bee which is an
academic competition.
Neuroscience Core Concepts for
K-12 teachers and students have been developed by members of the
public education and communications committee of the Society for
Neuroscience. Brain Facts, a downloadable primer on human brain
anatomy and function is currently being translated into Spanish and
other world languages.
Neuroscience is also beginning to become allied with
social sciences, and burgeoning
interdisciplinary fields of
neuroeconomics,
decision theory,
social neuroscience are starting to
address some of the most complex questions involving interactions
of brain with environment.
Neuroscience generally includes all scientific studies involving
the nervous system.
Psychology, as the
scientific study of mental processes, is closely related to
neuroscience, although the two disciplines are distinct, with such
subjects as
behaviorism and traditional
cognitive psychology studied
independently of the underlying neural processes. In
Principles
of Neural Science,
Nobel
laureate Eric Kandel contends that cognitive psychology is one
of the pillar disciplines for understanding the brain in
neuroscience. The term neurobiology is usually used interchangeably
with neuroscience, although the former refers specifically to the
biology of the
nervous system, whereas the latter refers to
the entire
science of the nervous
system.
Neurology,
psychiatry, and
neuropathology are medical specialties that
specifically address the diseases of the nervous system. These
terms also refer to clinical disciplines involving diagnosis and
treatment of these diseases. Neurology deals with diseases of the
central and peripheral nervous systems such as
amyotrophic lateral sclerosis
(ALS) and
stroke, while psychiatry focuses on
behavioural, cognitive, and emotional disorders. Neuropathology
focuses upon the classification and underlying pathogenic
mechanisms of central and peripheral nervous system and muscle
diseases, with an emphasis on morphologic, microscopic and
chemically observable alterations. The boundaries between these
specialties have been blurring recently, and they are all
influenced by
basic research in
neuroscience.
Integrative neuroscience
makes connections across these specialized areas of focus.
History
Evidence of
trepanation, the surgical
practice of either drilling or scraping a hole into the skull with
the aim of curing headaches or
mental
disorders or relieving cranial pressure, being performed on
patients dates back to
Neolithic times and
has been found in various cultures throughout the world.
Manuscripts dating back to 5000BC indicated that the
Egyptians had some knowledge about symptoms of
brain damage.
Early views on the function of the brain regarded it to be a
"cranial stuffing" of sorts. In Egypt, from the late
Middle Kingdom onwards, the brain
was regularly removed in preparation for
mummification. It was believed at the time that the
heart was the seat of intelligence. According
to
Herodotus, during the first step of
mummification: "The most perfect practice is to extract as much of
the brain as possible with an iron hook, and what the hook cannot
reach is mixed with drugs".
The view that the heart was the source of consciousness was not
challenged until the time of
Hippocrates. He believed that the brain was not
only involved with sensation, since most specialized organs (e.g.,
eyes, ears, tongue) are located in the head near the brain, but was
also the seat of intelligence.
Aristotle,
however, believed that the heart was the center of intelligence and
that the brain served to cool the blood. This view was generally
accepted until the Roman physician
Galen, a
follower of Hippocrates and physician to
Roman
gladiators, observed that his patients lost their mental
faculties when they had sustained damage to their brains.
In
al-Andalus
, Abulcasis, the father
of modern surgery, developed material and
technical designs which are still used in neurosurgery. Averroes suggested the existence of
Parkinson's disease and attributed
photoreceptor properties to the
retina.
Avenzoar
described
meningitis, intracranial
thrombophlebitis,
mediastinal tumours and made
contributions to modern
neuropharmacology.
Maimonides wrote about
neuropsychiatric disorders and described
rabies and
belladonna intoxication. Elsewhere in
medieval Europe,
Vesalius (1514-1564) and
René Descartes (1596-1650) also made
several contributions to neuroscience.
Studies of the brain became more sophisticated after the invention
of the
microscope and the development of
a staining procedure by
Camillo Golgi
during the late 1890s that used a
silver
chromate salt to reveal the intricate structures of single
neurons. His technique was used by
Santiago Ramón y Cajal and led
to the formation of the
neuron
doctrine, the hypothesis that the functional unit of the brain
is the neuron. Golgi and Ramón y Cajal shared the
Nobel Prize in Physiology
or Medicine in 1906 for their extensive observations,
descriptions and categorizations of neurons throughout the brain.
The hypotheses of the neuron doctrine were supported by experiments
following
Galvani's pioneering work in the
electrical excitability of muscles and neurons. In the late 19th
century,
DuBois-Reymond,
Müller, and
von Helmholtz showed neurons were electrically
excitable and that their activity predictably affected the
electrical state of adjacent neurons.
In parallel with this research, work with brain-damaged patients by
Paul Broca suggested that certain regions
of the brain were responsible for certain functions. At the time
Broca's findings were seen as a confirmation of
Franz Joseph Gall's theory that language
was localized and certain psychological functions were localized in
the
cerebral cortex. The
localization of function hypothesis was supported by observations
of
epileptic patients conducted by
John Hughlings Jackson, who correctly
deduced the organization of
motor
cortex by watching the progression of seizures through the
body.
Wernicke further developed the theory
of the specialization of specific brain structures in language
comprehension and production. Modern research still uses the
Brodmann cytoarchitectonic (referring
to study of
cell structure)
anatomical definitions from this era in continuing to show that
distinct areas of the cortex are activated in the execution of
specific tasks.
Major branches
Current neuroscience education and research activities can be very
roughly categorized into the following major branches, based on the
subject and scale of the system in examination as well as distinct
experimental or curricular approaches. Individual neuroscientists,
however, often work on questions that span several distinct
subfields.
| Branch |
Major topics |
Experimental and theoretical methods |
| Molecular and Cellular neuroscience |
neurocytology, glia, protein
trafficking, ion channel, synapse, action
potential, neurotransmitters,
neuroimmunology |
PCR, immunohistochemistry, patch clamp, voltage
clamp, molecular cloning,
gene knockout, biochemical assays, linkage analysis, fluorescent in situ
hybridization, Southern blots,
DNA microarray, green fluorescent protein,
calcium imaging, two-photon microscopy, HPLC, microdialysis |
| Behavioral
neuroscience |
behavioral genetics,
biological psychology,
circadian rhythms, neuroendocrinology, hypothalamic-pituitary-gonadal
axis, hypothalamic-pituitary-adrenal
axis, neurotransmitters,
homeostasis, dimorphic sexual-behavior,
motor control, sensory processing, photo reception, organizational/activational
effects of hormones, drug/alcohol effects |
animal models (gene knockout), in situ hybridization, golgi stain, fMRI, immunohistochemistry, functional genomics, PET, pattern recognition, EEG, MEG |
| Systems neuroscience |
primary visual cortex,
somatosensory system, perception, audition, sensory integration, population coding, Pain and nociception,
spontaneous and evoked
activity, color vision, olfaction, taste, motor system, spinal
cord, sleep, homeostasis, arousal,
attention |
single-unit recording,
intrinsic signal imaging,
microstimulation, voltage sensitive dyes, fMRI, patch clamp, genomics, training awake
behaving animals, local field
potential, ROC, cortical cooling, calcium imaging, two-photon microscopy |
| Developmental
neuroscience |
cell proliferation, neurogenesis, axon
guidance, dendrite development,
neuronal migration, growth factors,
neuromuscular junction,
neurotrophins, apoptosis, synaptogenesis |
Xenopus oocyte, protein
chemistry, genomics, Drosophila, Hox
gene |
| Cognitive
neuroscience |
attention, cognitive control, behavioral genetics, decision making, emotion, language, memory, motivation,
motor learning, perception, sexual
behavior, social
neuroscience |
experimental designs from cognitive psychology, psychometrics, EEG,
MEG, fMRI, PET, SPECT, single-unit
recording, human genetics |
| Theoretical and computational neuroscience |
cable theory, Hodgkin–Huxley model, neural networks, Voltage-gated ion channels,
Hebbian learning |
Markov chain Monte
Carlo, simulated annealing,
high performance
computing, partial
differential equations, self-organizing nets, pattern recognition, swarm intelligence |
| Diseases and aging: Neurology and
Psychiatry |
dementia, peripheral neuropathy, spinal cord injury, traumatic brain injury, autonomic nervous system, depression, anxiety, Parkinson's
disease, addiction, memory loss |
clinical trials, neuropharmacology, deep brain stimulation, neurosurgery |
| Neural engineering |
Neuroprosthetic, Brain-computer interface (BCI) |
Signal acquisition through EEG, ECoG, MEG, fMRI,
Near infrared
spectroscopy, EMG; signal
processing through pattern
recognition algorithms |
| Neurolinguistics |
language, Broca's area, language acquisition, speech perception, sentence processing |
theoretical models from psycholinguistics, cognitive science, and computer science;
experimental methods include EEG and ERP, MEG, fMRI,
PET, transcranial magnetic
stimulation, aphasiology, direct cortical stimulation |
| Neuroscience studies |
Neuroscience education: undergraduate models, best practices,
interface of neuroscience with all liberal arts disciplines,
neuroscience and society, philosophy of neuroscience,
interdisciplinary
research, neuroscience and popular culture, neuroscience and
the media |
| Neuroimaging |
structural imaging, functional imaging |
Computed tomography,
diffuse optical imaging,
event-related optical
signal, magnetic
resonance imaging, functional magnetic
resonance imaging,positron emission tomography,
single-photon
emission computed tomography |
Note: In 1990s, neuroscientist
Jaak
Panksepp coined the term "affective neuroscience" to emphasize
that emotion research should be a branch of neurosciences,
distinguishable from the nearby fields like cognitive neuroscience
or behavioral neuroscience. More recently, the social aspect of the
emotional brain has been integrated in what is called
"social-affective neuroscience" or simply social
neuroscience.
There has also been some research published arguing that some of
fair play and the
Golden Rule
may be stated and rooted in terms of neuroscientific and
neuroethical principles.
Major themes of research
Neuroscience research from different areas can also be seen as
focusing on a set of specific themes and questions. (Some of these
are taken from
http://www.northwestern.edu/nuin/fac/index.htm)
Allied and overlapping fields
Neuroscience, by its very interdisciplinary nature, overlaps with
and encompasses many different subjects. Below is a list of related
subjects and fields.
Future directions
See also
References
- Martin-Araguz, A.; Bustamante-Martinez, C.; Fernandez-Armayor,
Ajo V.; Moreno-Martinez, J. M. (2002). "Neuroscience in al-Andalus
and its influence on medieval scholastic medicine", Revista de
neurología 34 (9), p. 877-892.
- Greenblatt, SH., (1995) " Phrenology in the science and culture of the 19th
century, " Neurosurgery 37 790-805.
- Bear, M. F.; B. W. Connors, and M. A. Paradiso (2001).
Neuroscience: Exploring the Brain. Baltimore: Lippincott. ISBN
0-7817-3944-6.
- Principles of Neural Science, 4th ed. Eric R. Kandel, James H.
Schwartz, Thomas M. Jessel, eds. McGraw-Hill:New York, NY.
2000.
- Panksepp, J., 1990 - A role for “affective neuroscience” in
understanding stress: The case of separation distress circuitry.
In: Puglisi-Allegra, S. and Oliverio, A., Editors, 1990,
Psychobiology of stress, Kluwer, Dordrecht, pp.
41–58.
- Pfaff, Donald W., "The Neuroscience of Fair Play: Why We
(Usually) Follow the Golden Rule", Dana Press, The Dana Foundation, New
York, 2007. ISBN 9781932594270
Further reading
- Squire, L. et al. (2003). Fundamental
Neuroscience, 2nd edition. Academic
Press; ISBN 0-12-660303-0
- Byrne and Roberts (2004). From Molecules to Networks.
Academic Press; ISBN 0-12-148660-5
- Sanes, Reh, Harris (2005). Development of the Nervous
System, 2nd edition. Academic Press; ISBN 0-12-618621-9
- Siegel et al. (2005). Basic Neurochemistry, 7th
edition. Academic Press; ISBN 0-12-088397-X
- Rieke, F. et al. (1999). Spikes: Exploring the
Neural Code. The MIT Press;
Reprint edition ISBN 0-262-68108-0
- section.47 Neuroscience 2nd ed. Dale Purves,
George J. Augustine, David Fitzpatrick, Lawrence C. Katz,
Anthony-Samuel LaMantia, James O. McNamara, S. Mark Williams.
Published by Sinauer Associates, Inc., 2001.
- section.18 Basic Neurochemistry: Molecular,
Cellular, and Medical Aspects 6th ed. by George J. Siegel,
Bernard W. Agranoff, R. Wayne Albers, Stephen K. Fisher, Michael D.
Uhler, editors. Published by Lippincott, Williams & Wilkins,
1999.
- Damasio, A. R. (1994). Descartes' Error: Emotion, Reason,
and the Human Brain. New York, Avon Books. ISBN 0-399-13894-3 (Hardcover)
ISBN 0-380-72647-5 (Paperback)
- Gardner, H. (1976). The Shattered Mind: The Person After
Brain Damage. New York, Vintage
Books, 1976 ISBN 0-394-71946-8
- Goldstein, K. (2000). The Organism. New York, Zone
Books. ISBN 0-942299-96-5 (Hardcover) ISBN 0-942299-97-3
(Paperback)
- Llinas R. (2001). I of the Vortex: From Neurons to
Self MIT Press. ISBN 0-262-12233-2 (Hardcover) ISBN
0-262-62163-0 (Paperback)
- Luria, A. R. (1997). The Man with a Shattered World: The
History of a Brain Wound. Cambridge, Massachusetts
, Harvard
University Press. ISBN 0-224-00792-0 (Hardcover) ISBN
0-674-54625-3 (Paperback)
- Luria, A. R. (1998). The Mind of a Mnemonist: A Little Book
About A Vast Memory. New York, Basic
Books, Inc. ISBN 0-674-57622-5
- Medina, J. (2008). Brain Rules: 12 Principles for Surviving
and Thriving at Work, Home, and School. Seattle, Pear Press.
ISBN 0-979-777704 (Hardcover with DVD)
- Pinker, S. (1999). How the Mind Works. W. W. Norton & Company. ISBN 0-393-31848-6
- Pinker, S. (2002). The Blank Slate: The Modern Denial of
Human Nature. Viking Adult. ISBN 0-670-03151-8
- Ramachandran, V. S. (1998). Phantoms in the Brain.
New York, New York
Harper Collins.
ISBN 0-688-15247-3 (Paperback)
- Rose, S. (2006). 21st Century Brain: Explaining, Mending
& Manipulating the Mind ISBN 0099429772 (Paperback)
- Sacks, O. The Man Who Mistook His
Wife for a Hat. Summit Books ISBN 0-671-55471-9
(Hardcover) ISBN 0-06-097079-0 (Paperback)
- Sacks, O. (1990). Awakenings. New York, Vintage Books.
(See also Oliver Sacks) ISBN
0-671-64834-9 (Hardcover) ISBN 0-06-097368-4 (Paperback)
- Sternberg, E. (2007) Are You a Machine? The Brain,
the Mind and What it Means to be Human. Amherst, NY: Prometheus Books.
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