Article Figures & Data
Figures
- Figure 1.
Flowchart of methods pipeline: overview of data processing and analysis pipeline. Resting-state fMRI data were acquired in 16 individuals meeting DSM-IV criteria for ADHD and a group of 15 matched healthy controls. Data were corrected for a temporal shift in acquisition (slice timing), realigned to the middle slice, normalized to an EPI template, smoothed using a full width at half maximum kernel of 6 mm, detrended, and bandpass filtered (0.01–0.08 Hz). The six head-motion parameters (matched between the two groups), as well as the white matter and cerebrospinal fluid signals, were regressed out from each voxel's time course. Time courses were extracted for the 90 cerebral regions comprising the AAL template and the extent of dependency between every pair of regions was represented at the subject level with a 90 × 90 connectivity matrix. The resulting connectivity matrices were then investigated for between-group differences in connectivity using the network-based statistic as well as differences in key network measures. Intra-regional connectivity was also assessed from the EPI images (voxel wise) and the AAL regions of interest.
- Figure 2.
Measures of global topological attributes of brain connectivity. Multivariate measures describing topological attributes of brain connectivity were quantified in a drug-naive, non-clinical sample of young adults with ADHD and matched healthy controls. No significant differences were found between the two groups for the five measures and six densities considered. A, Characteristic path length and normalized characteristic path length. B, Average clustering coefficient and normalized average clustering coefficient. C, Small worldness.
- Figure 3.
Group differences in inter-regional functional connectivity. Two abnormal networks in ADHD identified with the NBS. In both panels, red lines indicate reduced inter-regional functional connectivity in the ADHD group compared with controls. In contrast, blue lines designate enhanced inter-regional functional connectivity in individuals with ADHD compared with healthy controls. A, Network 1: 1, superior frontal cortex; 2, mid-orbitofrontal cortex; 3, precentral gyrus; 4, amygdala; 5, lingual gyrus. B, Network 2: A, superior occipital cortex; B, fusiform gyrus; C, superior temporal gyrus; D, temporal pole; E, inferior part of the orbitofrontal cortex; F, medial orbitofrontal cortex.
- Figure 4.
Associations between values of intrinsic functional connectivity and symptoms of ADHD. A–C, Correlations between ADHD individuals' functional connectivity values in the left medial orbitofrontal-superior temporal connection (network 2) and the following: current symptoms of hyperactivity/impulsivity (A); total number of current symptoms (hyperactivity/impulsivity and inattention) (B); and number of past symptoms of hyperactivity/impulsivity (C). D, Representation of the correlation between the number of past symptoms of inattention and connectivity values in the left amygdala-right precentral gyrus connection (network 1).
Tables
Characteristics Controls (N = 15) ADHD (N = 16) Sex M/F, no 7/8 9/7 Age female, average (SD) 23.3 (±1.0) 23.8 (±1.0) Age males, average (SD) 22.4 (±0.9) 23.0 (±1.8) Handedness, Right/left, no 15/0 16/0 Formal education, years 16 16 Intelligence-Full scale (WASI) 114.7 (±8.7) 116.5 (±7.9) ADHD symptoms (average, SD) K-SADS Inattention (current)* 0.8 (±1.2) 6.8 (±1.0) K-SADS Hyperactivity/impulsivity (current)* 1.0 (±1.0) 5.4 (±2.4) K-SADS global (current)* 1.8 (±1.9) 12.3 (±2.6) K-SADS Inattention (past)* 0.8 (±1.4) 5.5 (±1.7) K-SADS Hyperactivity/impulsivity (past) * 0.8 (±1.5) 5.2 (±2.4) K-SADS global (past)* 1.7 (±2.4) 10.7 (±2.4) ↵*Between group difference (independent sample t test, p < 0.001). SD, Standard deviation.
Network connection density Regions showing a significant between-group difference in nodal clustering (1/N correction) Regions showing significant between-group difference in nodal path length (1/N correction) 10% Left inferior orbitofrontal cortex (p = 0.008), ⇑ 15% Right medial frontal cortex (p = 0.009), ⇓ 20% Right superior temporal cortex (p = 0.007), ⇑ Right superior occipital cortex (p = 0.008), ⇓ 25% Right superior temporal cortex (p = 0.009), ⇑ 30% Left superior occipital cortex (p = 0.010), ⇓ Note. ⇑ ADHD > healthy controls; ⇓ ADHD < healthy controls.
Anatomya p value x y z Network 1 Superior frontal cortex −20 31 43 Lateral orbitofrontal cortex −32 52 −11 p = 0.020 Precentral gyrus 40 −6 50 Amygdala −26 0 −18 Lingual gyrus 16 −68 −5 Network 2 Medial orbitofrontal cortex −7 51 −8 Inferior orbitofrontal cortex −40 32 −12 Temporal pole −47 14 −17 p = 0.005 Superior temporal gyrus −57 −22 6 Superior occipital cortex −23 −81 30 Fusiform gyrus 33 −41 −21 ↵aCoordinates (x, y, z) are given in Montreal Neurological Institute (MNI) atlas space and refer to the centroid of each AAL region. P values are all familywise error corrected for multiple comparisons.
- Table 4.
Average values of functional connectivity in the pairwise connections of interest (network-based statistic)
Controls ADHD Network 1 Amygdala–Precentral gyrus −0.10 (±0.03) 0.07 (±0.03) Lateral orbitofrontal cortex–Superior frontal cortex −0.07 (±0.04) 0.14 (±0.04) Lateral orbitofrontal cortex–Amygdala 0.10 (±0.05) −0.08 (±0.02) Lateral orbitofrontal cortex–Lingual gyrus −0.06 (±0.03) 0.08 (±0.02) Network 2 Superior temporal gyrus–Inferior orbitofrontal cortex 0.08 (±0.03) −0.13 (±0.04) Superior temporal gyrus–Medial orbitofrontal cortex 0.10 (±0.03) −0.05 (±0.03) Temporal pole–Superior occipital cortex −0.10 (±0.03) 0.11 (±0.04) Superior temporal gyrus–Fusiform gyrus −0.07 (±0.03) 0.13 (±0.04) Superior temporal gyrus–Temporal pole 0.04 (±0.04) 0.24 (±0.03) Standard error of the mean values are reported between brackets.
