The Biological Basis of Consciousness
Instructors:
C. Koch, PhD, California Institute of Technology
H. Berlin, PhD, MPH, Mount Sinai School of Medicine
Course description:
Since the beginning of civilization humans have contemplated consciousness and the mind-body
problem. However, a scientific approach to consciousness has been lagging. Indeed, for several
decades in the past century consciousness was taken to be either non-existent or not accessible to
any scientific investigation. Fueled by relevant findings in neuroscience, neuropsychology, and
cognitive science, consciousness is now taken to be a legitimate focus of scientific evaluation.
This semester we shall explore the rich empirical literature available on the topic.
What are the correlates of consciousness in the brain? These lectures will provide a
framework for addressing this question from a neuropsychological and neurobiological point of
view. The course will focus on the neuronal correlates of consciousness in animals and humans,
in both the laboratory and the clinic. These classes will offer students from all faculties an
introduction into one of life’s great mysteries: the phenomenon of consciousness. What are the
mechanisms underlying conscious experience? Are the standard concepts of modern science
sufficient to explain consciousness? How does the salty taste and crunchy texture of potato chips,
the unmistakable smell of dogs after they have been in the rain, the awfulness of a throbbing
tooth pain, or the sight of the summit illuminated by the setting sun, emerge from networks of
neurons and their associated synaptic and molecular processes? This class will emphasize the
empirical nature of the mind-body problem.
Since the bulk of the course material draws on neuronal and psychological evidence, you
should have some background in these areas. Having taken a course in neuroscience,
neuropsychology, physiological psychology, sensation and perception, or neurobiology will be
useful.
Grading:
All students taking the course for credit will receive a final number grade (0-100).
1) Class Participation (10% of grade): Class attendance, participation, and discussion are
required. You are expected to try answering questions posed in class by fellow students and the
instructor as well as raise questions and points of your own. Your active participation will not
only result in a more interesting class, it will also enhance your understanding of the course
material. If you can't attend a lecture, please let Dr Berlin or Prof. Koch know ahead of time.
Read all of the assignments carefully before you come to class. The quality of the class,
your excitement about what you are learning, and the interest with which you approach the
assignments will be influenced by the caliber of discussion. That, in turn, will depend on your
preparation. The topic is fascinating. Give it your best by being prepared for each class. So,
 Do not be afraid to ask and answer questions.
 Be prepared: Do the assigned readings before class.
 Think critically about the readings. What are the implications? What questions
do they raise? Do the studies resonate with your personal experiences?
 Fully participate in discussions
2) Quizzes (90% of grade): There will be 3 quizzes in total. Each quiz will consist of about 20
multiple choice questions that we will hand out at the end of class on Nov. 12, Dec 3, and Dec
12. You will have 15 minutes to complete the quiz. It will be based on the material of the
previous lectures and on the reading material.
Primary book for the class:
Koch, C (2004). The Quest for Consciousness: A Neurobiological Approach. Roberts and
Company Publishers: Englewood, Colorado.
Recommended texts:
Crick, F (1994).The Astonishing Hypothesis: The Scientific Search for the Soul. Simon and
Schuster: New York. (The most compelling overview of the problem. Compact and inexpensive
paperback.)
Edelman GM, Tononi G (2000). A Universe of Consciousness: How Matter Becomes
Imagination. Basic Books: New York. (A general introduction to the problem as well as to an
information theoretical approach to consciousness)
Searle, J (2004). Mind: A Brief Introduction. Oxford University Press: Oxford. (A concise
primer into the current philosophical debates surrounding consciousness, volition and related
philosophical conundrums. Professor Koch has written a review of this monograph
http://www.klab.caltech.edu/cns120/searle-04.pdf)
The following two books are great reference texts, but are not cheap. You can buy them used via
Amazon:
Kandel E, Schwartz J, Jessell T (2000). Principles of Neural Science, 4th edition. McGraw Hill:
USA. (This is the standard Neuroscience textbook. It will come in very handy but not in a literal
sense, given its 1,400+ page girth.)
Palmer, S (1999). Vision Science: Photons to Phenomenology. MIT Press: Cambridge, Mass.
(This book is a great introduction to those of you who want to delve deeper into the psychology
of vision as so much work on the neurobiology of consciousness involves visual perception.)
Schedule of Topics and Readings
Lecture 1, Oct. 29 by Berlin
Different states of consciousness and their pathologies (deep sleep, coma, vegetative & minimal
conscious states); brain death; communication with and waking minimal conscious patients
Reading: Chapter 1 in The Quest for Consciousness (QfC)
Laureys S. The neural correlate of (un)awareness: Lessons from the vegetative state. Trends
Cogn. Sci. 9: 556-9 (2005)
Owen AM, Cleman MR, Boly M, Davis MH, Laureys S and Pickard JD. Detecting awareness in
the vegetative state. Science 313: 1402 (2006).
Lecture 2, Nov. 5 by Berlin
What do split-brain patients and agnosia teach us about consciousness?
Reading: Chapters 13 and 17 in QfC.
Lecture 3, Nov. 12 by Berlin
Unconscious information processing and dissociations of consciousness in patients and normals.
Reading: Dijksterhuis A, Bos MW, Nordgren LF, and van Baaren RB. On making the right
choice: the deliberation-without-attention effect. Science 331:1005-7 (2006).
Anderson MC, Ochsner KN, Kuhl B, Cooper J, Robertson E, Gabrieli SW, Glover GH, Gabrieli
JD. Neural systems underlying the suppression of unwanted memories. Science 303:232-5
(2004).
Lecture 4, Nov. 26 by Koch
What are the neuronal correlates of consciousness (NCC); basic assumptions underlying this
approach; the visual processing hierarchy; the NCC are not in primary visual cortex.
Reading: Chapters 6 and 7 in QfC
Crick FC and Koch C. Are we aware of neural activity in primary visual cortex? Nature 375:
121-3 (1995).
Lee SH, Blake R and Heeger DJ. Hierarchy of cortical responses underlying binocular rivalry.
Nat Neurosci 10: 1048-54 (2007).
Lecture 5, Nov. 28 by Koch
How to track the NCC using bistable and other perceptual illusions; binocular rivalry in monkeys
and humans.
Reading: Chapter 16 in QfC
Blake R and Logothetis NK. Visual competition. Nature Reviews Neuroscience 3: 13-21 (2002).
Lecture 6, Dec. 3 by Koch
What is the relationship between selective attention and consciousness? fMRI and psychophysics
of attention without consciousness; consciousness without attention.
Reading: Chapters 9 and 10 in QfC
Koch C and Tsuchiya N. Attention and consciousness: Two distinct brain processes. Trends
Cogn Sci 11: 16-22 (2007).
Lecture 7, Dec. 5 by Koch
Unconscious sensory-motor behaviors; zombie systems; vision-for-perception is different from
vision-for-action; your zombie acts faster than you see.
Reading: Chapters 12 and 13 in QfC.
Lecture 8, Dec. 10 by Koch
The problem of free will; (i) the conscious perception of freedom of action and its neuronal
correlates; (ii) Libet’s experiments relating to the readiness potential;
(iii) quantum
indeterminacy and the brain.
Reading: Libet B, Gleason CA, Wright EW and Pearl DK. Time of conscious intention to act in
relation to onset of cerebral activity (readiness-potential): The unconscious initiation of a freely
voluntary act. Brain 106: 623-42 (1983)
Haggard P and Eimer M. On the relation between brain potentials and conscious awareness. Exp.
Brain Res. 126: 128-33 (1999)
Haggard P. Conscious intention and motor cognition. Trends Cog Sci. 9: 290-5 (2005).
Lecture 9, Dec. 12 by Koch
The strength and limits of characterizing the neuronal correlates of consciousness. the need for a
theory of consciousness; Tononi’s theory of integrated information and consciousness; what
have we learned from human consciousness that might be relevant to machine consciousness.
Reading: Tononi G. An information integration theory of consciousness. BMC Neuroscience. 5:
42-72 (2004).
Koch C and Tononi G. What can biology tell us about machine consciousness? forthcoming.