1. Professor, Anesthesiology and Psychology
Default mode speaker
Stuart Hameroff MD
Professor, Anesthesiology and Psychology
Director, Center for Consciousness Studies
The University of Arizona, Tucson Arizona

2. “Whilst part of what we perceive comes though our senses from the object before us, another part (and it may be the larger part) always comes out of own head.”
William James, 1890

3. The ‘Cartesian Theater’
For Des For Descartes, content of consciousness
li like a like a play on stage
The ‘Cartesian Theater’

4. Simon and Newell developed similar
brain/mind computer architectures
CPU

5. stimuli, arousal, response - bottom-up, top-down,
Baars, Edelman/Tononi, Changeux/
Dehaene, Crick/Koch cast thalamo-cortical
oscillations, recurrence, global
workspace broadcasting……
Based on
hierarchical sensory
stimuli, arousal, response -
bottom-up, top-down,
feed-forward, feedback..

6. PET, fMRI show reduced metabolism, blood flow in thalamo-cortical hierarchical arousal pathways with anesthesia and loss of consciousness –
a ‘thalamo-cortical switch’ (Alkire)

7. In neuroscience, consciousness has been viewed in the context of sensory processing and response, i.e. attention-based tasks
But what about mental states without sensory inputs?
What about task-free, stimulus-independent thought, internally-generated states, mind wandering, episodic memory, meditation, daydreaming?

8. The Brain's Dark Energy/Default mode networks
Raichle (2006) Science 314: 1249 – 1250, 2006)

9. MTL: Medial temporal lobe mPFC: Medial prefrontal cortex
Carhart-Harris, R. L. et al. Brain : ; doi: /brain/awq010
DMN regions in orange
MTL: Medial temporal lobe
mPFC: Medial prefrontal cortex
PCC: Posterior cingulate cortex
pIPL: Posterior inferior parietal
Copyright restrictions may apply.

10. Regions of the brain regularly observed to decrease their activity during attention demanding cognitive tasks. These data represent a metaanalysis of nine functional brain imaging studies performed with PET and analyzed by Shulman and colleagues (49). In each of the studies included, the subjects processed a particular visual image in the task state and viewed it passively in the control state. One hundred thirty-two individuals contributed to the data in these images. These decreases appear to be largely task independent. The images are oriented with the anterior at the top and the left side to the reader's left. The numbers beneath each image represent the millimeters above or below a transverse plane running through the anterior and posterior commissures (26).
Brain regions regularly observed to decrease activity during attention demanding cognitive tasks
Raichle M E et al. PNAS 2001;98:
©2001 by The National Academy of Sciences

11. Axial (A) and coronal (B) images showing default-mode network for healthy young subjects. Green arrows highlight coactivation in hippocampus and entorhinal cortex.

12. Axial (A) and coronal (B) images showing default-mode network for healthy young subjects. Green arrows highlight coactivation in hippocampus and entorhinal cortex.

13. Default-mode
networks:
healthy elderly
Default mode
Alzheimers

16. what about internally-generated mental states without sensory inputs?
Default mode network activity is one type of intrinsic neuronal activity which was considered noise, until brain-wide correlations in the ‘noise’ were discovered (? Israel)
DMN activities require 95% of the energy required for thalamo-cortical sensory processes
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

17. The brain operates in two distinct modes –
1) Attention-based sensory processing, task
performance (Thalamo-cortical)
2) Mindwandering, episodic memory,
internally-generated states daydreaming,
thinking…? (Default mode networks)

18. Default mode networks:
Episodic memory Thinking about consciousness
Introspection Meditation
Self-referential thought Creativity
Daydreaming Jamesian fringe
Mind wandering Freudian Id
Envisioning the future Anesthesia
Gauging others’ perspective Sleep
Context/filling in

19. Default mode networks:
Diminished in Alzheimers, autism?
Overactive in schizophrenia, anxiety, OCD?

20. The brain operates in two distinct modes –
1) Attention-based sensory processing, task
performance (Thalamo-cortical)
2) Mindwandering, episodic memory,
internally-generated states daydreaming,
thinking…? (Default mode networks)

21. The brain operates in two distinct modes –
1) Attention-based sensory processing, task
performance (Thalamo-cortical)
2) Mindwandering, episodic memory,
internally-generated states daydreaming,
thinking…? (Default mode networks)
and flips back and forth between the two
on the order of roughly 10 seconds
‘Anticorrelated networks’ (Raichle)

22. J Neurophysiol 101: , First published April 1, 2009; doi: /The Global Signal and Observed Anticorrelated Resting State Brain Networks
Michael D. Fox1,*, Dongyang Zhang1,*, Abraham Z. Snyder1,2 and Marcus E. Raichle1,2,3,4
The Global Signal and Observed Anticorrelated Resting State Brain Networks
MD Fox, D Zhang, AZ Snyder and ME RaichleJ Neurophysiol 101: , 2009

23. what about internally-generated mental states without sensory inputs?
Questions:
1) How does switching between sensory/attention/task and mindwandering/default modes occur?
Locus coeruleus ? (UCSB group)
based on saliency of sensory input?
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

24. what about internally-generated mental states without sensory inputs?
Questions:
2) What is/are the function(s) of
default mode network activity?
Raichle: Synchrony and orchestration
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

25. “Default mode networks synchronize all parts of the brain, so like racers in a track competition, they are all in a proper ‘set mode’ when the starting gun goes off.” Raichle 2010

26. “Orchestrator of The Self : The DMN is thought to behave something like an orchestra conductor, issuing timing signals, much as a conductor waves a baton, to coordinate activity among different brain regions. This cuing—among the visual and auditory parts of the cortex, for instance—probably ensures that
all regions of the brain are ready to react in concert to stimuli.” Raichle, 2010

27. Steve Lehar

28. what about internally-generated mental states without sensory inputs?
Questions:
3) What about consciousness? What does
default mode network activity tell us about
consciousness?
Thalamo-cortical sensory processing and
behavior can be either conscious,
or non-conscious
Default mode network activity can either be
conscious, or non-conscious
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

29. what about internally-generated mental states without sensory inputs?
Thalamo-cortical processing (driving to work)
can be either conscious or non-conscious
(‘auto-pilot’, zombie mode) with daydreaming,
mindwandering
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

30. what about internally-generated mental states without sensory inputs?
Default mode network activity can either be
conscious (daydreaming about vacation on
the beach)….
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

31. what about internally-generated mental states without sensory inputs?
Default mode network activity can either be
conscious (daydreaming about vacation on
the beach) or non-conscious (tough
day ahead at work, send impulses to small
bowel, tighten sphincters…..)
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

32. what about internally-generated mental states without sensory inputs?
Activity supporting consciousness switches between
1) Thalamo-cortical input-driven processing
and
2) Default mode network activity
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

33. what about internally-generated mental states without sensory inputs?
Consciousness switches between
1) Thalamo-cortical input-driven processing
and
2) Default mode network activity
Thalamo-cortical activity is hierarchical, but how is default mode network activity mediated? Self-organized?
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

34. what about internally-generated mental states without sensory inputs?
Consciousness switches between
1) Thalamo-cortical input-driven processing
and
2) Default mode network activity
Could consciousness involve some self-organizing neuronal process moving between the two modes?
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

35. what about internally-generated mental states without sensory inputs?
Consciousness switches between
1) Thalamo-cortical input-driven processing
and
2) Default mode network activity
Could consciousness involve some self-organizing neuronal process moving between the two modes?
What distinguishes conscious from non-conscious brain activity?
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

36. EEG is divided into
frequency bands:
Delta (< 4 Hz)
Theta (4 to 8 Hz)
Alpha (8 to 12 Hz)
Beta (13 to 30 Hz)
Gamma (> 30 Hz)
Coherence in gamma synchrony
among different brain regions is
the best correlate of consciousness
The best neurophysiological
correlate of consciousness
(NCC) comes from EEG,
voltage fluctuations recorded
from scalp or brain surface.

37. Gap junction-mediated gamma synchrony in
olfactory bulb cortex correlates with conscious smell .
J Neuroscience.
26(8): , 2006
Neuron46(5):761-72, 2005
BING!!

38. Neuroscience.
159(4): , 2009
Brain Research.
1156:46-58, 2007
Conscious feelings of pleasure, sex and reward correlate with gap junction-mediated gamma synchrony in dopaminergic nucleus accumbens
BING!!

39. EEG measures post-synaptic
dendritic activity
(not axonal firings)

40. Biological brain neuron
McCulloch-Pitts
artificial neuron,
Perceptron
Toy neuron

41. Integrate

42. Fire

43. Integrate

44. Fire

48. B I N G !

49. BING!! BING!!

50. B I N G !

51. The “conscious pilot”—dendritic synchrony moves through the brain to mediate consciousness. Journal of Biological Physics, 36:1 January, 2010
DOI: /s x

52. what about internally-generated mental states without sensory inputs?
Conclusions - Raichle work implies
The brain switches between sensory-driven and (self-organizing) internally-driven modes
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

53. what about internally-generated mental states without sensory inputs?
Conclusions - Raichle work implies
Consciousness switches between sensory-driven and (self-organizing) internally-driven modes
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?

54. what about internally-generated mental states without sensory inputs?
Conclusions - Raichle work implies
Consciousness switches between sensory-driven and (self-organizing) internally-driven modes
Anesthesia cannot depend solely on a
thalamo-cortical switch
what about internally-generated mental states without sensory inputs?
Stimulus-independent thought, e.g. meditation, daydreaming, mind wandering?