Dipole source localization of event-related brain activity indicative of an early visual selective attention deficit
L M Jonkman1, J L Kenemans, C Kemner
1Department of Neurocognition, Faculty of Psychology, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands. l.jonkman@psychology.unimaas.nl
Insights
Children with attention-deficit hyperactivity disorder (ADHD) show early visual selective attention deficits, impacting target selection. This may stem from an early filtering issue around 200ms, affecting brain activity.
Area of Science:
- Neuroscience
- Developmental Psychology
- Cognitive Science
Background:
- Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention and hyperactivity.
- Selective attention is crucial for filtering relevant information and is often impaired in ADHD.
- Event-related brain potentials (ERPs) offer insights into the timing and neural basis of cognitive processes.
Purpose of the Study:
- To investigate early selective attention deficits in the visual modality of children with ADHD using ERPs.
- To identify the brain areas responsible for visual processing deficits in ADHD through source localization.
Main Methods:
- A visual color selection task was performed by 18 children with ADHD and 18 controls (ages 7-13).
- Electroencephalography (EEG) recorded ERP activity from 30 electrodes.
- Brain source localization was applied to ERP data.
Main Results:
- ADHD children had lower perceptual sensitivity and poorer target selection.
- Smaller frontal selection positivity (FSP) around 200 ms in ADHD children indicated an early selective-attention deficit.
- Later visual processing (occipital and fronto-central activity, 200-400 ms) was unaffected.
Conclusions:
- ADHD children experience difficulties with selective visual processing, potentially due to an early filtering deficit (absent FSP) around 200 ms.
- Source localization suggests abnormalities in attention-modulated activity in lateral frontal areas during the 200-400 ms timeframe.
- Further research is needed to precisely identify the neural sources of these visual processing deficits in ADHD.
Objective:
This study was aimed at investigating whether attention-deficit hyperactivity disorder (ADHD) children suffer from specific early selective attention deficits in the visual modality with the aid of event-related brain potentials (ERPs). Furthermore, brain source localization was applied to identify brain areas underlying possible deficits in selective visual processing in ADHD children.
Methods:
A two-channel visual color selection task was administered to 18 ADHD and 18 control subjects in the age range of 7-13 years and ERP activity was derived from 30 electrodes.
Results:
ADHD children exhibited lower perceptual sensitivity scores resulting in poorer target selection. The ERP data suggested an early selective-attention deficit as manifested in smaller frontal positive activity (frontal selection positivity; FSP) in ADHD children around 200 ms whereas later occipital and fronto-central negative activity (OSN and N2b; 200-400 ms latency) appeared to be unaffected. Source localization explained the FSP by posterior-medial equivalent dipoles in control subjects, which may reflect the contribution of numerous surrounding areas.
Conclusions:
ADHD children have problems with selective visual processing that might be caused by a specific early filtering deficit (absent FSP) occurring around 200 ms. The neural sources underlying these problems have to be further identified. Source localization also suggested abnormalities in the 200-400 ms time range, pertaining to the distribution of attention-modulated activity in lateral frontal areas.
