Libertad y Neurociencia


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Conferencia de Adolf Tobeña sobre Neurociencia y Libertad, realizada en Tarragona el 30/10/2010 dentro del ciclo organizado por cultura 3.0 "Verdad, belleza, bien, felicidad, libertad y justicia a la luz de la ciencia moderna".

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Libertad y Neurociencia

  1. 1. Free will, freedom and the brain Adolf Tobeña Dept. of Psychiatry, UAB Institute of Neurosciences Bellaterra (Barcelona) Cultura 3.0 Tercera Cultura Tarragona, 2010.
  2. 2. By LIBERTY, is understood, according to the proper signification of the word, the absence of external Impediments: which Impediments, may oft take away part of a man power to do what he would. Thomas Hobbes
  3. 3. Individual freedom and socially sanctioned liberties usually collide, to the point of converting freedom and independence in perfectly orthogonal properties FREEDOM: the absence of necessity, coercion or constraint in choice or action. …assumes free will, fully autonomous agents with the abbility to make open choices/actions.
  4. 4. Cashmore AR (2009), PNAS, 107, 10, 4499-4504.
  5. 5. Cashmore AR (2009), PNAS, 107, 10, 4499-4504. WILL: Intention, choice CONSCIOUS+UNCONSCIOUS THOUGHTS: Brain workings GES: Genes+Environmental history+Stochasticism
  6. 6. Free agents?: Measuring conscious intention Haggard P (2008) Human volition: towards a neuroscience of will, Nature Reviews Neuroscience, 9, 934-946
  7. 7. Measuring conscious intention Haggard P (2008) Human volition: towards a neuroscience of will, Nature Reviews Neuroscience, 9, 934-946
  8. 8. Layers of consciousness Self-monitoring and insight Recognition instant Focused attention Awareness Alertness/Drowsiness Sleep stages Coma Thalamus-Cortical loops Ongoing work at monoamine midbrain and brainstem Arousing Systems
  9. 9. Neurohormonal subsystems contributing to brain’s vigilance/alertness/mood Brainstem and midbrain arousal systems Insight Consciousness Agency Awakening Vigilance Sleep Unwilled actions: sonambulisms, “alien hand” syndromes, motor jerks…
  10. 10. Self-consciousness interacting with Others´ consciousness: The Social Brain Self-monitoring and insight Recognition instant Others Intentions/Actions Focused attention Awareness World Objects Alertness/Drowsiness Sleep stages Body movements/position/ signals Coma
  11. 11. A. Implanting intentions to act (willingness) by stimulating directly into the brain B. Restricted islands of consciousness permitting willing choices C. Moral handicaps linked to willingness deficits THREE EXPERIMENTAL APPROACHES TO WILLFUL ACTIONS/DECISIONS
  12. 12. Desmurget M et al (2009), Science, 324, 811- 814. Direct Electrical Stimulation (DES) in 7 patients with brain tumors
  13. 13. When points of the Posterior Parietal Cortex got stimulated patients expressed desires or intentions to move, although no movement actually occured: “Stimulation of all these sites produced a pure intention, that is, a felt desire to move without any overt movement being produced... Without prompting by the examiner, all three patients spontaneously used terms such as “will,” “desire,” and “wanting to,” which convey the voluntary character of the movement intention and its attribution to an internal source, that is, located within the self” High intensity stimulation of the same area made the patients believe that they had in fact moved, although they didn't move a muscle: “with higher electrode currents conscious motor intentions were replaced by a sensation that a movement had been accomplished but no actual movement was observed. Thus, these patients experienced awareness of an illusory movement. For example, patient PP3 reported after low-intensity stimulation of one site (5 mA, 4 s; site a in Fig. 1), “I felt a desire to lick my lips” and at a higher intensity (8 mA, 4 s), “I moved my mouth, I talked, what did I say?”
  14. 14. When certain points on the Premotor Cortex were stimulated, the patients moved, but they were not aware that they had done so: “During stimulation, patient PM1 exhibited a large multijoint movement involving flexion of the left wrist, fingers, and elbow ... He did not spontaneously comment on this, and when asked whether he had felt a movement he responded negatively”
  15. 15. MRI and 3D images of the patient brain and stimulation sites. T= tumor; 1, 5, 4 = conscious intention+illusory movement; 3 = conscious intention; 2 = visual illusion (background movement);
  16. 16. Haggard P (2009), Science, 324, 731-732.
  17. 17. Instant recognition/decision upon moving world objects: awareness limits? Rester challenge: At 200 Km/h: 0,43 sec At 210 Km/h: 0,41 sec At 220 Km/h: 0,39 sec At 230 Km/h: 0,37 sec Nadal problem
  18. 18. Simulation (Fair) Constraints Interactions Real (unperceived) external world The unconscious brain Conscious ExperiencesConscious Experiences Experienced external world (perceived) Public cognitive space Inner cognitive experiences (thoughts, images...). Private cognitive space Inner bodily sensations, feelings. Private bodily space
  19. 19. Consensual approach to the function of consciousness A simplified, smothed and apparently sustained but transient and everchanging display of external/internal world (Late) detection of errors ulterior adjustments + feeling of agency Permitting
  20. 20. Gray’s model: engineers plus neuroscience minimal system for consciousness COMPARATOR STORED REGULARITIES GENERATOR OF PREDICTIONS PLANS THE WORLD
  21. 21. Simulation (Fair) Constraints Interactions Real unperceived external world The unconscious brain Conscious ExperiencesConscious Experiences Experienced external world (perceived) Public cognitive space Inner cognitive experiences (thoughts, images...). Private cognitive space Inner bodily sensations, feelings. Private bodily space ???
  22. 22. Research frontiers on consciousness Gross neural “disconnections” (vegetative states, minimally conscious brain-injured patients). Decoding ongoing mental states in normals. Unconscious processing (default brain systems, burying and revealing memories, as examples).
  23. 23. “Wakefulness without awareness” CLINICAL CRITERIA FOR PATIENTS IN A VEGETATIVE STATE • Time duration: One month at least; if persistent, more than one year; almost always permanent. • No cognition: absence of consistent responses to linguistic, symbolic or mimetic instruction. • No semantically meaningful sounds or goal-directed movements • No sustained head-ocular pursuit activity • Functions usually or often preserved: - Brain stem and autonomically controlled visceral functions: Homeothermia, osmolar homeostasis, breathing, circulation, gastrointestinal functions. - Pupillary and oculovestibular reflexes. - Brief, inconsistent shifting of head or eyes toward new sounds or sights. - Smiles, tears or rage reactions. - Reflex postural responses to noxious stimuli.
  24. 24. Owen AM and ColemanMR (2008) Nature Reviews Newuroscience, 9, 235-243
  25. 25. Detecting awareness in a vegetative state Owen AM et al (2006), Science, 313, 1402, 8 Sept.
  26. 26. Detecting awareness in a vegetative state Owen AM et al (2006), Science, 313, 1402.
  27. 27. Detecting awareness in a vegetative state Owen AM et al (2006), Science, 313, 1402, 8 Sept. Dozens of statements like “there was milk and sugar in this coffee”, presented in blocks against matched verbal noise- segments.
  28. 28. Boly M et al (2007) Neuroimage,36, 979-992 An fMRI test based on mental imagery tasks to detect “awareness” in vegetative- state patients: validation studies in normal volunteers at Cambridge and Liege (12 males at each place) . Group conjoint comparisons between spatial navigation and tennis tasks compared to one another. 30 seconds of imagery engagement at every step after scarce instructions, for seven repetitions plus blind SPM analyses.
  29. 29. Boly M et al (2007) Neuroimage,36, 979-992. Group results (right) and individual results (above), showing pre- SMA activations during all tasks.
  30. 30. Monti MM et al (2010), The New England Journal of Medicine, 362,7, 579-589.
  31. 31. Unconscious (working) modes Typical: Preconscious (i.e. procedural memories) Repressed unconscious (i.e. buried images) Deep unconscious (i.e. grammatical rules) Nonconscious (i.e. secretion of serotonin) Added: Agency (intentions+choices) readiness
  32. 32. There are ways to connect the domain of individual freedom and the domain of political liberty, spanning from the personal, psychological features of agency constitutive of (free) will to the social, relational aspects of agency constitutive of political freedom. Freedom in the agent (i) the freedom of the action performed by the agent; (ii) the freedom of the self implicit in the agent’s ability to identify with the things thereby done, rather than having to look on them as a bystander; (iii) the freedom of the person involved in enjoying a social status that makes the action truly her own, not an action produced under pressure by others. “Connotations” of freedom: (i) responsibility: the agent can be rightly held responsible for what he or she did; (ii. ownership: the action is one that the agent can own or identify with; and (iii) underdetermination: the agent’s choice was not fully determined at least by certain sorts of antecedents (e.g., hypnotic suggestion). Freedom as property to be held responsible Ph. Pettit (2001): A theory of freedom: from the psychology to the politics of agency
  33. 33. Origins of Morality • “Of all the differences between man and the lower animals, the moral sense or conscience is by far the most important. This sense has a rightful supremacy over every other principle of human action; it is summed up in that short but imperious word ought, so full of high significance. It is the most noble of all the attributes of man, leading him without a moment's hesitation to risk his life for that of a fellow creature; or after due deliberation, impelled simply by the deep feeling of right or duty, to sacrifice it in some great cause.” • Charles Darwin (1871): The Descent of Man and Selection in Relation to Sex.
  34. 34. BIOLOGY OF THE PROBLEM OF CHOICE How nervous systems: 1. Frame the finite choices available 2. Value the choices 3. Choose an option based on these valuations Humans may choose courses of action against biological imperatives and constraints .…they do not have free choice but they posses a capacity for flexible choice. A capacity which is behind cognitive innovation “Freedom is the capacity to achieve what is of value in a range of circumstances” Nicholas Maxwell
  35. 35. Neural deficits Adult ventromedial-orbital prefrontal lesions (Gage type) * Early onset prefrontal lesions * Others… Neural typologies (Normative Exceptional temperaments) Psychopaths * Narcissistic Messianic Glory cravers .... Amoral/hypermoral tendencies within the brain * Solid evidence FROM FREE AND FULLY RESPONSIBLE INDIVIDUALS TO AMORAL MINDS Will has been also conceived as a faculty providing discipline (top-down hard mental work) in the face of ease and temptation…
  36. 36. Moral cognition and its neural constituents WD Casebeer (2004) Nature Reviews Neuroscience, 4, 840. From moral intuitions to moral agency and ethics
  37. 37. Impairment of social and moral behavior related to early damage in human prefrontal cortex • Steven W. Anderson, Antoine Bechara, Hanna Damasio, Daniel Tranel & Antonio R. Damasio Department of Neurology, Division of Behavioral Neurology and Cognitive Neuroscience, The University of Iowa College of Medicine, Iowa City, Iowa 52242, USA • Nature Neuroscience, November 1999, Volume 2, Number 11, pp 1032 - 1037. The long-term consequences of early prefrontal cortex lesions occurring before 16 months were investigated in two adults. As is the case when such damage occurs in adulthood, the two early-onset patients had severely impaired social behavior despite normal basic cognitive abilities, and showed insensitivity to future consequences of decisions, defective autonomic responses to punishment contingencies and failure to respond to behavioral interventions. Unlike adult-onset patients, however, the two patients had defective social and moral reasoning, suggesting that the acquisition of complex social conventions and moral rules had been impaired. Thus early-onset prefrontal damage resulted in a syndrome resembling psychopathy.
  38. 38. Impairment of social and moral behavior related to early damage in human prefrontal cortex Steven W. Anderson et al (1999), Nature Neuroscience, 2, 11, 1032 - 1037.
  39. 39. * Initial loan: 2000 US dollars * 4 card decks (A, B, C, D) to select with different monetary values per card: SAFE/GOOD A,C cards : rewards (50) punishments (40-100) RISKY/BAD B,D cards: rewards (100) punishments (200-400) * 4 sec. before each attempt: measure of anticipatory SCR’s. * Every 10 trials stop: questioning taped GAME RUNNING OVER 100 TRIALS (Unknown to the subjects) Gambling task in Gage-type patients vs. controls
  40. 40. Impairment of social and moral behavior related to early damage in human prefrontal cortex Steven W. Anderson et al (1999), Nature Neuroscience, 2, 11, 1032 - 1037.
  41. 41. Social and moral reasoning stages Impairment of social and moral behavior related to early damage in human prefrontal cortex Anderson SW et al (1999), Nature Neuroscience, 2, 11, 1032 - 1037.
  42. 42. Marsh AA et al (2008) American J. Psychiatry, 165, 712-70.
  43. 43. Marsh AA et al (2008) American J. Psychiatry, 165, 712-70.
  44. 44. De Oliveira-Souza, Hare RD, Bramati IE, Garrido GJ, Azevedo-Ignazio F, Tovar-Moll F and Moll J (2008), Neuroimage, 40, 1202-1213.
  45. 45. De Oliveira-Souza et al (2008), Neuroimage, 40, 1202-1213.
  46. 46. The moral basis of human cognition J Moll, R Zahn, R de Oliveira Souza, F Krueger and J Grafman (2005), Nature Reviews Neuroscience, 799-809. a. Cortical areas related to morality b. Subcortical areas related to morality c. Cortical areas non-related to morality Pyramid of values
  47. 47. Shenhav A and Greene JD (2010), Neuron, 67, 667-677. 34 valid subjects (17 females, age = 24,3), were studied across five different Dilemma scenarios, with 10 self-paced variations each one. fMRI acquisitions at a Siemens 3T equipment, Mass General Hospital (Boston).
  48. 48. Shenhav A and Greene JD (2010), Neuron, 67, 667-677.
  49. 49. Shenhav A and Greene JD (2010), Neuron, 67, 667-677.
  50. 50. …In general, life is
  52. 52. From Laplace Demon to Biological Flexibility/Adaptiveness Neural systems allow: - Selfgenerated motion - Agency monitoring of choices, thoughts and actions Transient and constrained autonomy (degrees of freedom…, not freedom)
  53. 53. 1. The experience that we are free to choose our actions (on at least some occasions). This experience of free will occurs at the time of an act and for its duration. It may be conceived of as a perceptual phenomenon. 2. Experiential belief, a belief "attached" to, or addressing, an ongoing experience (and temporally related to the latter). 3. The abstract belief that we are free or not free (which may occur at times remote from specific acts). These aspects of free will are potentially separate. I may, for instance, experience myself as a free agent, free in my volition, choosing to move or act in a certain way, but I might also believe that I am not free, that my thoughts and acts result from genetic and environmental influences, and that at some ultimate level of analysis I am not as free as I feel (or experience myself). Sean A Spence (1996) Free Will in the Light of Neuropsychiatry Philosophy, Psychiatry & Psychology 3, 2, 75-90 The "problem of the freedom of the will" breaks down into 3 aspects which are phenomenologically distinct
  54. 54. Cerf M et al (2010), Nature, 467, 1104-1108.
  55. 55. Cerf M et al (2010), Nature, 467, 1104-1108.