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Attention Deficit Hyperactivity Disorder
Attention Deficit Hyperactivity Disorder
T. FISHER , H. PRATT and J. AHARONT. FISHER , H. PRATT and J. AHARON
Evoked Potentials LaboratoryEvoked Potentials Laboratory
Technion-Israel Institute of Technology, Haifa, Israel Technion-Israel Institute of Technology, Haifa, Israel
The three main symptoms of
ADHD
Inattention
Impulsivity
Hyperactivity
What are the brain processes associated with the
behavioral impulsivity symptoms?
Subjects
14 subjects diagnosed with Attention Deficit
and Hyperactivity disorder.
14 healthy control subjects matched for age
and gender
Age range: 18-30. No co-morbidity of
psychiatric, neurological or learning disabilities.
All subjects were free of medication.
Procedure• Stimuli: 2 binaural tones: 1000 Hz (NO-GO)
2000 Hz (GO) 60 dBnHL for 40 ms.
Inter-trial interval: 1000 to 2000 ms
• Task: To GO trials: press button to stimuli. Probability: 80%.
To NO-GO trials: inhibit the response. Probability: 20%.
GO NO-GO Behavioral Results
go mean reaction time
200
250
300
350
400
GO MEAN
ms
ec CTRL
ADHD
% correct
70
75
80
85
90
95
100
GO CORRECT NOGO CORRECT TOTAL ERRORS
CTRL
ADHD
Electrophysiological resultsgrand average, 28 subjects, midline electrodes
+
-15 µV
300Msec
Control subjects ADHD subjects
GO
NO-GO
P3
N2
N2
P3
P3
N2
N2
P3
P3
P3
N2 N2
ADHD vs. CTRL in NO-GO Trials
CTRL
ADHD
+-5 µV
300Msec
Control > ADHD
LORETA images of Control – ADHD difference
ADHD Control
+
-
15 µV
300msec
No go , significant voxels, P<0.05187 -207 msec
stimulus
R. Inf. frontal gyrus BA 9, 44,45
Posterior Cingulate BA 23,29,30,31
LORETA images of significant T values
ADHD Control
+
-
15 µV
300Msec
No go , significant voxels, P<0.05308-339 Msec
stimulus
Control > ADHD
Conclusions
• The ADHD deficit is in stimulus-related processing, not at the perceptual level.
• ADHD show abnormal activity in brain regions attributed to response inhibition and conflict monitoring.
CTRL N2
ADHD N2
N2
ADHD P3
CTRL P3
