Consciousness as an alternate
interpretation of corollary
discharges
M.Karthikeyan
Y9277
Mentor: 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 button
7. 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
Time
in ms
Active-Medium positive
STD DEV
1
A-49.11ms
P-425.3ms
2
A-189.3ms
P-267.7ms
Subject
Time
in ms
Active-Negative
Subject
3
A-114.25
P-35.52
4
A-106
P-70.1
5
A-237
P-961.3
6
A-69.8
P-262.5
7
A-120.2
P-558.55
Time in
ms
Active-Very high positive
STD DEV
8
A-74.33
P-278.32
9
A-189.34
P-267.7
10
A-233.8
P-342.01
Subject
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):63640.)
• Thank You!