consciousness as an alternate interpretation of corollary discharges m.karthikeyan y9277 mentor:...
TRANSCRIPT
Consciousness as an alternate interpretation of corollary discharges
M.KarthikeyanY9277Mentor: Prof.Amitabh Mukherjee
AIM•Understanding the nature of
consciousness.•Are corollary discharges (signals in the
brain) what we call as consciousness??•How materialistic is consciousness??
Concepts involved
•Efference signal•Efference copy signal•Forward Internal Model•Corollary Discharge•Reafferent signal
Experimental Procedure• Subjects – 9 Schizophrenic (corollary discharge pathway
affected) patients from Mahendru Hospital,Kanpur.• Methodology:1.Patients were shown a red circle , the stimulus to press a
button.2.Had to say yes when they sensed their intention to press the
button.3.Finally press the button.4.I noted the time instant of ‘YES’ on a millisecond stopwatch.5.Button press time instant was recorded by the software.6.Active trial - subject himself pressed the button7.Passive trial – I pushed the patients finger onto the button• Active trials – 2 sample and 5 subject trials• Passive trials – 2 sample and 5 subject trials
Active-Medium positive
Subject
Time in ms
STD DEV1 A-49.11msP-425.3ms2A-189.3msP-267.7ms
Active-Negative
Subject
Time in ms
3A-114.25P-35.524A-106P-70.15A-237P-961.36A-69.8P-262.57A-120.2P-558.55
Active-Very high positive
Subject
Time in ms
STD DEV8A-74.33P-278.329A-189.34P-267.710A-233.8P-342.01
Data Analysis• The first five results were as expected , resulting
in late realization of action execution. • Time gap difference corresponded to the
subject’s extent of schizophrenia (various levels of the condition)
• Explanations for the very high positive time gaps ??
Scope for improvement•Drawbacks:1.Number of subjects available were low ,
larger number of trials performed per subject.
2.Time instant of ‘YES’ obtained by taking into account the experimenter’s error.
•Highly accurate time estimates might be possible by using EEG(electroencephalography) i.e the exact time instant of conscious realization.
References• 1.Sukhvinder S.Obhi , (Evidence for feedback
dependent conscious awareness of action(Brain Research,2007 1161:88-94).
• 2.Libet, B. (1985) Unconscious cerebral initiative and the role of conscious will in voluntary action. Behavioural and Brain Sciences, 8: 529:566.
• 3. Irwin Feinberg (Efference copy and corollary discharge: implications for thinking and its disorders . Schizophrenia bulletin 1978;4(4):636-40.)
•Thank You!