was that me? probing the neurocognitive basis of the sense of agency

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Was that me? Probing the neurocognitive basis of the sense of agency Matthis Synofzik Dept. of Neurodegeneration Hertie-Institute for Clinical Brain Research University of Tübingen Germany

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Was that me? Probing the neurocognitive basis of the sense of agency. Matthis Synofzik Dept. of Neurodegeneration Hertie-Institute for Clinical Brain Research University of Tübingen Germany. Definitions. Sense of agency= the registration that we are the initiators of our actions - PowerPoint PPT Presentation

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Was that me?

Probing the neurocognitive basis of the sense of agency

Matthis Synofzik

Dept. of NeurodegenerationHertie-Institute for Clinical Brain Research

University of Tübingen Germany

Definitions

Sense of agency= the registration that we are the initiators of our actions

- does not require:- any direct phenomenal awareness (≠ Gallagher, 2007)- any meta-representations of self-agency (Frith, 2005; Stephens & Graham (2000)- the conceptual ability to register self-agency (de Vignemont & Fourneret, 2004)

Sense of body ownership= the sense that my body is moving regardless of whether the movement is

voluntary or involuntary

- does not require:- any active movement- any efferent action information/forward models

A multifactorial two-step account of the sense of agency

Hypothesis: The sense of agency is a complex supramodal, internal representation of largely

heterogeneous functional and (self-)representational levels.

Judgement of agency= conceptual, interpretative representation

- specific belief formation about the origins of the sensation- essentially an ad hoc theorizing about oneself as influenced by contextual cues and belief states

Feeling of agency= preconceptual, perceptual representation

- weighting and integration of different sensorimotor authorship cues:(a) congruency= experience of self-agency by

coherent flow of action processing(b) incongruency= action as peculiar/strange

Synofzik, Vosgerau & Newen, Consc & Cog, 2007

Not self-caused

Self-caused

My action!

Charlie‘s action!

The feeling of agency (FoA)

Hypothesis: The feeling of agency is produced by a gradual and highly plastic subpersonal

weighting process of different action-related perceptual and motor cues.

(1) A sensory prediction of one’s movements is one of the factors entering the FoA.

(2) This prediction is adaptable by sensory feedback.

?

Synofzik et al., J Neurophysiol, 2006

Visual Feedback

PD Pointing Direction

90°

Condition 1: Feedback Trials

Synofzik et al., J Neurophysiol, 2006

PPD Perceived PD

Visual Feedback

PD Pointing Direction

90°

Condition 1: Feedback Trials

Synofzik et al., J Neurophysiol, 2006

PD Pointing Direction

PPD Perceived PD

90°

Condition 2: Perceptual Control Trials

Synofzik et al., J Neurophysiol, 2006

PPD Perceived PD

PD Pointing Direction

90°

Condition 2: Perceptual Control Trials

Synofzik et al., J Neurophysiol, 2006

Results normal subjects

1) Subjects‘ perception of their hand movementsadapted by 15° in the direction of visual feedback rotation.

2) This effect was independent from the fact whethervisual feedback was presented immediately before or not.(i) We use external agency cues – especially visual feedback- to inform the SoA.(ii) The SoA per se, however, is internal, supramodal in nature ( main thesis!). An „internalization“ of one‘s own „external“ reafferences

3) We did not test for qualitative, dichotomic agencyjudgements („Was the movement you have seen causedby yourself or not?“), but for the gradual amount o afferent information for which self-agency is claimed („Indicate the movement you have performed“). measure of the FoA

4) The only partial adaptation reflects a fundamental dilemma when interacting with the world: Don‘t rely too much on exafferent feedback vs. use this feedback for recalibrating our sensory predictions/ the FoA.

5) The FoA should not be seen in terms of a static dichotomy between self-produced and not self-produced, but as a result of a gradual and – as shown here – highly plastic process that constantly allows the subject to redefine the causal relations to its surroundings.

Synofzik et al., J Neurophysiol, 2006

Results schizophrenia patients

1) Schizophrenia patients over-rely on external reafferences.

fail if external feedback is temporarily not available or ambigous

2) Internal predictions for perception per se are not impaired.

Delusions of influence might result from an insufficient exploitation of internal predictions/proprioception within the multi-modal integration of action-related information.

Problem of integrating multimodal sensorimotor authorship information (rather than of a problem of the internal prediction per se).

Synofzik et al., in preparation

Perceptual Control TrialsFeedback Trials

Interim summary

Thesis: The feeling of agency is the result of weighting and integrating different

sensorimotor authorship cues.

Experiment 1 (normal subjects)

1.

2.

Synofzik, Vosgerau & Newen, Consc & Cog, 2007

Interim summary (cont`)

Experiment 2 (schizophrenia patients)

Thesis: The feeling of agency is the result of weighting and integrating different

sensorimotor authorship cues.

Synofzik, Vosgerau & Newen, Consc & Cog, 2007

How can we explain delusions of control?

Thesis: Delusions of control are best accounted for by a two-step account.

Impairment in belief formation (JoA):(i) an alien experience is not

accepted as a strange experience.

(ii) a delusional agency hypothesis about the perceived fact is formed out.

(iii) this is maintained despite different stored encyclopedic knowledge about their behaviour and despite the testimony of others.

Synofzik, Vosgerau & Newen, Consc & Cog, 2007

Shortcomings in present research on the SoA

Daprati et al., 1997; Franck et al., 2001; Farrer et al., 2003, David et al., 2007

(i) Most experiments investigating the SoA explore the level of JoA, but not the level of FoA.

(ii) The diversity of neural correlates of the SoA results from differences of conceptual notions of the SoA.

Conclusions

1) The basic feeling of agency is produced by a gradual and highly plasticsubpersonal weighting process of different action-related perceptual and motor

cues.

2) This preconceptual core is further processed by conceptual capacities and belief stances to form a judgement and attribution of agency.

3) The extent to which the feeling and the judgement of agency, respectively, contribute to the overall SoA depends on the context and task requirements (e.g. ambiguity, complexity, context conditions, psychological and social situation).

4) Thus, the SoA is a dialectic combination of both, bottom-up processes (as

emphasized by Frith et al., 2000) and top-down processes (as emphasized by Stephens & Graham,

2000).

Overall thesis: The sense of agency is a complex supramodal, internal representation of largely

heterogeneous functional and (self-)representational levels.

Thank you!

Axel Lindner

Peter Thier

Philosophy

Gottfried Vosgerau

Albert Newen

Cognitive Neuroscience

The gradual contributions of the two agency representations

stable,unequivocal circumstances

FoA

JoA

unstable,ambigous circumstances

SoA

SoA

(i) can explain a peculiar perceptual experience, but not the actual agency attribution (especially not the exact external agent)

(ii) even in cases of mismatch the action is sometimes attributed to oneself

(iii) even when sufficient information for an internal comparison, i.e. efference copy and visual feedback, is given, persons might not be able to self-attribute their own actions (e.g. patients with impaired proprioceptive feedback, Fourneret et al., 2002)

(iv) there are other sources of peculiar action experiences and of self-attribution, which do not even need to involve motor actions at all

Limitations of the comparator model:1) it‘s not sufficient

Limitations of the comparator model:2) it‘s not necessary

Aarts et al., 2005

Perceptual self-attribution

Wegner et al., 2004

Priming

SoA ≠ sense of initiation

(i) - the representational content of the SoA is not only determined by the action initiation per se- but also refers to the guidance and consequences of one’s actions and the causal relation between action intention, action performance, and action consequences

(ii) patient GL has a SoI, but not a SoA

Action initiationIndependent from any sensory bodily

consequences or sensory effects

Agency of an actionRelates to bodily consequences

and/or action effects

How should we individuate the SoA ?

SoA ?

SoA ?

SoA ?

Outlook

1) Test the differential contributions of the various factors to the FoA.

3) Explore pathological disruptions of agency for the specific factor/level that is disrupted (e.g. alien hand; anosognosia for one’s own hemiparesis, anarchic hand).

2) Dissociate FoA and JoA within one experiment (behavioural/neuroimaging). And, in a next step: double dissociate FoA, FoO, JoA, and JoO.

A multifactorial two-step account of the sense of ownership

Hypothesis: Also the sense of ownership is a complex supramodal phenomenon of largely

heterogeneous functional and (self-)representational levels.

Rubber hand illusion( e.g. Haggard/Tsakiris)

„alien hand“

Critique:• There is no need for any comparator for having a sense of ownership.• There is not even the need for any intentional stance or for multimodal feedback.• Unimodal sensory feedback (e.g. proprioception) can be sufficient

1. The explanation of the sense of ownership

Gallagher, TICS, 2000; similar in Gallagher, 2005.

Critique:• There is no information about the actual movement and action effects available.• A match at the “feed-forward comparator” can only provide a sense of initiation.• Sense of intiation ≠ sense of agency!

2. The explanation of the sense of agency

Gallagher, TICS, 2000; similar in Gallagher, 2005.

Visual Feedback

PD Pointing Direction

90°

Clockwise!

Threshold paradigm: Exemplary Trial

Visual Feedback

PD Pointing Direction

90°

counterclowise!

Threshold paradigm: An exemplary trial

Impairments in perceiving one’s own hand movements correlate with delusions of control

The feeling of agency is gradual

Schizophrenia patients with delusions of control are impaired in perceiving the sensory consequences of their actions, i.e. to compensate for self-induced retinal image motion.

Lindner et al., Curr Biol 2005

No need for a comparator

Wegner et al., 2004

The experimental paradigm

Was sind “interne sensorische Vorhersagen”?

Wolpert and Flanagan, 2001

Das Grundprinzip Ein Beispiel

Interne sensorische Vorhersagen im Kleinhirn?

fMRI-Aktivität im Kleinhirn korreliert mit der Verzögerung zwischen Bewegung und selbstinduzierter taktiler Stimulation

Kleinhirn: signalisiert die sensorische Differenz zwischen vorhergesagten und tatsächlichen sensorischen Konsequenzen einer Bewegung

Blakemore et al., 2001

PD Pointing DirectionTF Target Flash Motor Error

Bedingung 3: Motor Control Trials