Table 1.
Functional magnetic resonance imaging studies of sustained attention in Schizophrenia
| Ref. | Participants | Task and behavioral results | fMRI methods and results |
| Volz et al[57], 1999 | SCZ (n = 14), age 34.1 ± 12.3, males 78.6%, medicated 100% | CPT-IP. Type of stimuli: lettersTNS = 720, Target = 25%, SET = 600 ms, ISI = 1200 ms, TET = 30 min | 1.5 T, block design (4 blocks). baseline: finger tapping Whole brain analysis. Imaging package: SPM96 |
| NC (n = 20), age 28.2 ± 5.7, males 60% | Required response: on targets.Behavioral measures: hit rate, mean RT, d’, ln b Results: no between group differences | Results: NC > SCZ in the R mesial PFC, ACC and L TH | |
| Eyler et al[58], 2004 | SCZ (n = 8)/SCA (n = 1) age 58.9 ± 9.9, males 55.6%, illness duration: 33 yr, medicated 100% | CPT-X. Type of stimuli: letters. TNS = 72Target = 33.3% ISI = 500 ms, TET = 6 min 3 s | 1.5 T, block design. baseline: digit fixation 8 task blocks and 9 baseline blocks Whole brain analysis. Imaging package: AFNI |
| NC (n = 10), age 59.8 ± 5.7, 12 males 60% | Required response: on targets Behavioral measures: mean RT, d’ Results: no between group differences | Results: NC > SCZ in R IFG/insula (BA 47/45)SCZ > NC in R postcentral gyrus (BA 3) and L cerebellum | |
| Salgado-Pineda et al[59], 2004 | SCZ (n = 14), age 25.5 ± 4.1, males 50%, medicated 100%, illness duration: 1.9 yr | CPT-IP. Type of stimuli: numbers. TNS = 900Target = 15% ISI = 1100 ms, TET = 14min | 1.5 T, block design. baseline: digit response |
| 2 task blocks and 2 baseline blocks. Whole brain analysis. Imaging package: SPM2 | |||
| NC (n = 14), age 25.1 ± 3.3, males 50% | Required response: on targets Behavioral measures: omission errors, commission errors, mean RT, d’, ln bResults: Between group differences-omissions, commission and d’: NC > SCZ-mean RT: SCZ > NC | Results:NC > SCZ in R IFG (BA 44), R angular gyrus (BA 39), R STG (BA 37), R MTG (BA 21), R TH | |
| Honey et al[60], 2005 | N-SCZ: SCZ with both negative and positive symptoms: (n = 11), age 42.6 ± 9.2, males 90.9%, age of onset: 22.2 yr, medicated 100% | CPT-X with 2 levels of difficulty: undegraded and degraded stimuli (0% and 40% pixel inverted). Type of stimuli: digits TNS = 280 Target = 25% SET = 42 ms, ISI = 958 ms TET = 6 min | 3T, block design, baseline: screen fixation 10 task blocks and 10 baseline blocks. Imaging package: SPM2 Masked brain analysis (ROIs involved in attention processing, differentiating the groups and showing a task related activity associated to attentional load). Connectivity analysis (seed ROIs: ACC and cerebellar vermis) |
| P-SCZ: SCZ with predominant positive symptoms: (n = 11) age 41.1 ± 9.2, males 81.8%, age of onset: 24.7 yr, medicated 100% | Required response: on targets Behavioral measures: mean RT, d’Results: N-SCZ were less accurate than NC in target discrimination (d’) | Results Task vs baseline:NC > (P-SCZ = N-SCZ) in R and L angular gyrus, MFG, L putamen(P-SCZ = N-SCZ) > NC in R and L SFG, R and L IPL, R SPL, R post central gyrus, L precentral gyrus, R and L TH, ACC, PCC, R MiFG, R IFG, cerebellum; P-SCZ > N-SCZ in R STG, R MiFG and L SPL | |
| NC (n = 12), age 33.3 ± 11.8, 12 males 83.3% | Connectivity with ACC:NC > (P-SCZ = N-SCZ) in R and L MSFG, R and L IFG; (P-SCZ = N-SCZ) > NC in R and L precentral gyrus, R postcentral gyrus, cerebellum; P-SCZ > N-SCZ in ACC; N-SCZ > P-SCZ in SMA | ||
| Connectivity with cerebellum:NC > (P-SCZ = N-SCZ) in R and L MSFG, L MFG; (P-SCZ = N-SCZ) > NC in L MiFG; P-SCZ>N-SCZ in R and L IFG, ACC, L SPL, R precentral gyrus, L postcentral gyrus | |||
| Morey et al[61], 2005 | UHR (n = 10), age 22.6 ± 4.4, male 50%, medicated 20%, | Visual oddball taskType of stimuli: circles (“targets”), squares (frequent non targets-“standards”), objects (rare non targets-“novels”) | 1.5T, 7 runs. Event-related design. Imaging package: SPM99ROI analysis: ACC, MiFG, IFG, BG, and TH. Conditions: -Targets-Novels-Standards (baseline) |
| Early SCZ (n = 15) age 24.1 ± 6.5, male 67%, age of onset 22.3 yr, illness duration 1.7 yr, medicated 86.7% | TNS = 1400 Target = 3% SET = 500 ms, ISI = 1500 ms, TET = 36 min 24 s Required response: on both targets and non-targets | ResultsTargets vs novels activations-in ACC, MiFG and IFC: NC > UHR, Early SCZ and Chronic SCZ-in IFG: (1) NC> Early SCZ and Chronic SCZ; (2) only NC and UHR showed R > L activations, whereas Early SCZ and Chronic SCZ showed a reduced laterality | |
| Chronic SCZ (n = 11) age 38.1 ± 7.7, male 82%, age of onset 22.9 yr, illness duration 15.3 yr, medicated 100% | Behavioral measures: hit rate, d’, B’’ | Target vs baseline activations: -in ACC, MiFG and IFC: NC > Early SCZ and Chronic SCZ -in BG and TH: NC > Early SCZ and Chronic SCZ (results confirmed comparing Chronic SCZ with Older NC) | |
| NC (n = 16) age 28.0 ± 11.6, male 59% Older NC (n = 10) age 34.0 ± 12.1, male 67% | Results: Between group differences: -Hit rate: NC > Early SCZ and chronic SCZ -d’: NC > UHR, Early SCZ and Chronic SCZ | ||
| Liddle et al[62], 2006 | SCZ (n = 24)/SCA (n = 4) age 31.6 ± 10.1, males 67.9%, illness duration 7 yr, medicated 96.4% | Auditory oddball task Type of stimuli: 1500 Hz tones (“targets”), 1000 Hz tones (frequent non targets-“standards”), noises (rare non targets-“novels”) | 1.5 T, event related design, whole brain analysis Imaging package: SPM99. Conditions: -correct targets-correct novels-correct standards (baseline)-missed targets-standard false alarms |
| NC (n = 28), age 28.2 ± 8.9, males 75 % | TNS = 488 Target = 10% SET = 200 ms, ISI = 2000 ms, TET = 16 min Required response: on targets Behavioral measures: RT, omissions, commissions | ResultsTargets vs baseline activations: NC > SCZ: in L and R amygdala, R hippocampus, R and L STS, L and R insula, R and L orbitofrontal cortex (BA 47), ACC, PCC, L and R SPL, R and L IPL, L and R middle IFG, L and R superior MFG, L and R TH, L and R striatum, L and R cerebellum | |
| Results: SCZ were significantly slower and less accurate than NC | |||
| ResultsTargets vs novels activations: NC > SCZ in: L amygdala, L orbitofrontal cortex (BA 47), L anterior insula, rostral ACC and L striatum | |||
| Gur et al[63], 2007 | SCZ (n = 22), age 30.5 ± 9.1, males 59.1%, age of onset 22.5 yr, illness duration 12.4 yr, medicated 95.5% | Visual oddball task. Stimuli: colored shapes Type of stimuli: red circles (“targets”), green circles (frequent non targets-“standards”), fractal images (rare non targets-“novels”) | 4T, event related design, whole brain analysis. Imaging package: FEAT/FMRIB. Conditions: -targets-novels-standards (baseline) |
| NC (n = 28), age 31.6 ± 8.5, males 57.1 % | TNS = 200 Target = 15% SET = 1000 ms, ISI = 2000 ms, TET = 7 minRequired response: on targetsBehavioral measures: hit rate, RT | ResultsTargets vs baseline activations: NC > SCZ in R and L STG, L insula, R and L putamen, ACC, PCC, L SFG, L THSCZ > NC in R insula, R MiFG, L IPL | |
| Results: no between group differences | Novels vs baseline activations: NC > SCZ in L IOG and L IPL SCZ > NC in L MOG, L fusiform, L precuneus, L IFG, R angular gyrus, SOG, SPL, MiFG | ||
| Harrison et al[64], 2007 | SCZ (n = 12), age 32.2 ± 8.0, males 100%, medicated 100% | Multi-Source Interference Task (MSIT). Type of stimuli: digits SET = 2000 ms, ISI = 500 ms TNS = 160, TET = 11 min Required response: on all stimuli Behavioral measures: correct responses, RT | 3T, block design. Imaging package: SPM5 Conditions: -low difficulty Task (“baseline”)-high difficulty Task (“Task”)-fixation (“Rest”) |
| Whole brain analysis and ROI analysis of deactivation (“Rest”-“Task”) in medial PCC/rostral ACC and PCC/Precuneus | |||
| NC (n = 14), age 31.7 ± 8.0, males 100% | Results: no between group differences | ResultsSCZ > NC in deactivation of medial PCC/rostral ACC and PCC/Precuneus. In SCZ the magnitude of deactivation correlates with response speed and level of emotional awareness | |
| Wolf et al[65], 2008 | SCZ (n = 16)/SCA (n = 1) age 31.9 ± 7.1, males 53 %, illness duration 9.9 yr, medicated 94.1% | Auditory oddball taskType of stimuli: 2000 Hz tones (“targets”), 1000 Hz tones (frequent non targets-“standards”), sounds (rare non targets-“novels”) | 4T, event-related whole brain analysis. Imaging package: FEAT/FSL. Conditions:-targets -novels -standards (baseline) |
| NC (n = 21), age 28.6 ± 7.1, males 52% | TNS = 200 Target = 15% SET = 150 ms, ISI = 1850 ms, TET = 6 min and 40 s Required response: on targets Behavioral measures: hit rate, RTResults: SCZ were significantly slower than NC | ResultsTargets vs baseline activations: SCZ > NC in: L precentral gyrus, ACC/SMA, L and R insula, L hippocampus, L and R STG/MTG, L superior MOGNovels vs baseline activations: SCZ > NC in: L IFG | |
| Filbey et al[66], 2008 | POC-SCZ (n = 6) age 53, males 33.3% medicated 0% (drug naïve) | Sustained attention taskType of stimuli: colored circlesRequired response: on targets Behavioral measures: RT | 1.5T. Block design. Imaging package: FSL Whole brain analysis baseline condition: circles fixation |
| NC (n = 8) age 41, males 62.5% | Results: no between group differences | ResultsNC > POC-SCZ in: R IPL (BA 7), R SPL (BA 7), R MTG (BA 21), R MOG (BA 18), R PCC (BA 31), R SFG (BA 10), R lingual gyrus (BA 18/19), R precentral gyrus (BA 9/43), R parahippocampal gyrus (BA 28), L cuneus (BA 18), L striatum; POC-SCZ > NC in: L STG (BA 21), L SFG (BA9) and R MTG (BA 19) | |
| Carter et al[67], 2010 | SCZ (n = 9), age 29.8 ± 12.0, males 100% | Visual selective attention task Type of stimuli: colored circles | 4T. Block/event-related mixed design. 10 runs. Imaging package: SPM. Conditions: -target events (3 s before-13.5 s after the event) -transient activation (3 s before-7.5 s after the onset of task block) -sustained activation (15 s before-70.5 s after the onset of task block) |
| NC (n = 12), age 25.5 ± 4.6, males 100% | TNS = 1960 Target = 5 %SET = 500 ms, ISI = 1000 ms TET = 49 minRequired response: on both targets and non-targets Behavioral measures: correct targets, RT | Masked brain analysis and ROI analysis in ACC, IFG, MiFG, IPS, BG, caudate and TH | |
| Results-correct target percentage: NC > SCZ-RT: SCZ > NC | Results -During transient activation NC > SCZ in: MiFG, IPS, caudate and TH-During target events NC > SCZ in THIn NC: positive correlation between accuracy and TH activation during sustained activation condition; In SCZ: negative correlation between RT and BG activation during target events | ||
| Sepede et al[68], 2010 | REL-SCZ (n = 11), age 34.4 ± 8.8, males 45.5% medicated 0% (drug naïve), smokers 36.4% | CPT-X with 3 levels of difficulty: undegraded and degraded stimuli (0%, 25% and 40% pixel inverted). Type of stimuli: digits | 1.5T, event-related design, 3 runs (0%, 25% and 40% degraded) Whole brain analysis. Imaging package: BrainVoyager QX 1.9 |
| NC (n = 11), age 32.0 ± 5.2, males 45.5%, smokers 36.4% | TNT = 210, Target = 16% SET = 200 ms, ISI = 2000 ms, TET = 42 min | Task conditions: -correct responses on target -incorrect responses on target -correct responses on non-targets (baseline) | |
| Required response: on targets and non-targets Behavioral measures: correct targets, correct non-targets, RT Results: no between group differences | Results Correct targets vs baseline: NC > REL-SCZ in R precentral gyrus (BA 6/9), R and L insula (BA 13), MFG/dorsal ACC (BA 9/32)REL-SCZ > NC in deactivating PCC/retrosplenial cortex (BA 23/31) Incorrect target vs baseline: REL-SCZ > NC in L insula/IFG (BA 13/47) and R TH |
SCZ: Schizophrenic patients; NC: Normal comparisons; SCA: Schizoaffective patients; REL-SCZ: Unaffected first degree relatives of schizophrenic patients; POC-SCZ: Presumed Obligate carriers of schizophrenic patients; UHR: Ultra high risk subjects; SET: Stimulus exposure time; ISI: Interstimulus interval; TNS: Total number of stimuli; TNT: Total number of targets; TET: Total experiment time; RT: Response time; R: Right; L: Left; PFC: Prefrontal cortex; ACC: Anterior cingulate cortex; PCC: Posterior cingulate cortex; MFG: Medial frontal gyrus; MSFG: Medial superior frontal gyrus; IFG: Inferior frontal gyrus; SFG: Superior frontal gyrus; SMA: Supplementary motor area; IPL: Inferior parietal lobule; SPL: Superior parietal lobule; IPS: Intraparietal sulcus; MTG: Middle temporal gyrus; STG: Superior temporal gyrus; STS: Superior temporal sulcus; MOG: Middle occipital gyrus; IOG: Inferior occipital gyrus; TH: Thalamus; BG: Basal ganglia.