Table 2 Food-image tasks in the study of anorexia nervosa

Neuropsychology: Attention

Distraction

Dickson et al., 2008 [19]

Working memory task.

Effects of image presentation on reaction time and accuracy.

24 AN (R)

30.6 (9.0)

16.0 (1.0)

Yes

No

No differences AN vs HC

6

24 HC

33.1 (8.0)

21.9 (2.0)

Brooks et al., 2012 [20]

Working memory and inhibitory control task. Effects of image presentation on reaction time and accuracy.

13 AN (R)

25 (11.0)

15 (1.54)

Yes

Yes

Distraction during working memory task: AN > HC

Distraction during inhibitory control task: AN < HC

7

20 HC

22 (5.0)

22.38 (2.66)

Neimeijer et al., 2017 [18]

Visual target detection task. Effects of image presentation on accuracy.

66 AN (57.5% R, 42.5% EDNOS AN-R)

15.25 (1.86)

15.45 (1.79)

Yes

No

Distraction AN > HC

6

55 HC

16.14 (1.9)

20.45 (2.10)

Recognition

Nikendei et al., 2008 [62]

Participants view images. Recognition and recall.

16 AN (81.25% R, 18.75% BP)

22.8 (U)

14.8 (2.3)

Yes

No

No differences AN vs HC

9

16 HC, fasted

23.6 (U)

U

16 HC, sated

23.1 (U)

U

Visual probe detection

Veenstra & de Jong 2012 [24]

Exogenous cueing task: participants detect targets that appear in one of two on-screen locations; distractor image (food or neutral stimuli) precedes target onset, appearing in either the same (valid trials) or opposite (invalid trials) location as the target. Response time.

88 AN (61.3% R, 28.7% EDNOS AN-R)

15.02 (1.37)

15.69 (1.90)

Yes

No

No differences AN vs HC

6

76 HC

15.12 (1.75)

20.42 (2.37)

Cardi et al., 2012 [28]

Dot-probe task: Participants instructed to detect targets appearing in one of two on-screen locations, either replacing a food or neutral image that are presented concurrently.

Response time.

18 AN (33% R, 11% BP, 55% EDNOS-AN)

31.5 (11.4)

17 (2.6)

Yes

No

No effect of intervention on attentional bias towards food

5

19 HC

28.6 (8.0)

23.9 (2.8)

Cardi et al., 2013 [27]

38 AN (21% EDNOS)

29.9 (7.92)

16.2 (2.35)

Yes

No

Attentional bias towards food inpatients: pre-meal < post-meal Attentional bias towards food outpatients: pre-meal > post-meal

6

Kim et al., 2014 [23]

31 AN

23.1 (9.35)

15.15 (2.51)

Yes

Yes

No differences AN vs HC

7

33 HC

22.18 (2.14)

20.91 (2.22)

Cardi et al., 2015 [29]

19 AN

31.0 (10.0)

16.7 (2.7)

Yes

Yes

No differences AN vs HC

7

23 BN

24.4 (5.7)

23.4 (6.9)

36 HC

25.9 (5.0)

21.5 (2.0)

Leppenan et al., 2017 [26]

30 AN

26.2 (6.82)

16.3 (2.04)

Yes

Yes

Attentional bias away from food: AN > HC

8

29 HC

26.83 (8.54)

23.25 (3.65)

Eye-tracking

Giel et al., 2011 [32]

Eye movements recorded while participants view pairs consisting of a food and neutral image.

Number and duration of fixations on images.

19 AN (73.6% R, 26.4% BP)

24.4 (4.1)

15.8 (1.8)

Yes

Yes

Attentional bias towards food: AN < HC

7

20 HC, sated

24.2 (2.9)

21.3 (1.7)

18 HC, fasted

24.4 (2.6)

21.6 (1.5)

Neuropsychology: Reward

Explicit rating

Bossert et al., 1991 [53]

Participants view images.

Palatability ratings.

9 AN (R)

21.9 (2.9)

66.1(8.5) IBW

No

No

Palatability high calorie food: AN < HC

Palatability low calorie food: AN > HC

8

20 BN

21.7 (2.9)

101.9 (12.9) IBW

9 HC

22.3 (1.2)

100.8 (4.8) IBW

Jiang et al., 2010 [46]

Participants view images.

Liking and wanting ratings.

17 AN (R)

26.47 (7.12)

15.04 (1.93)

Yes

Yes

Liking: AN < HC

Wanting: AN < HC

6

29 HC

24.52 (5.58)

20.38 (1.87)

Krizbai et al., 2016 [52]

Participants view images.

Valence, dominance, arousal ratings.

14 AN (R)

15.07 (1.38)

16.92 (1.73)

No

No

Positive valence: AN < HC

5

14 HC

15.14 (1.29)

20.51 (2.50)

Implicit rating

Cowdrey et al., 2013 [41]

Binary forced choice procedure: across multiple trials participants choose between two foods, each of which may be high or low calorie and sweet or savoury.

Relative response time to select high and low-calorie foods (implicit wanting).

20 AN (80% R, 20% BP)

26.4 (10.56)

16.33 (1.1)

No

No

Explicit wanting high calorie food: AN < HC; AN-WR < HC

Implicit wanting high calorie food: AN < HC; AN < AN-rec; AN-WR < HC

Implicit wanting low calorie food: AN > HC; AN > AN-rec; AN-WR > HC

4

22 AN-WR (82% R, 18% BP)

25.1 (6.03)

21.05 (1.89)

22 AN-rec (82% R, 18% BP)

23.73 (5.76)

21.03 (1.53)

41 HC

24.29 (6.46)

21.7 (1.88)

Approach-Avoidance

Spring & Bulik, 2014 [51]

Affect misattribution procedure: participants briefly view food images, which are replaced by Chinese characters. Pleasantness ratings of Chinese characters (implicit liking).

9 AN

21.4 (5.79)

U

Yes

No

Implicit liking: AN < HC

6

14 AN-rec

29 HC

Veenstra & de Jong, 2011 [54]

Manikin Task: participants move manikin towards or away from images presented on-screen depending on orientation of image (horizontal or vertical).

Errors/reaction times on approach versus avoidance trials (approach bias).

89 AN (60.7% R, 39.3% EDNOS AN-R)

14.84 (1.70)

15.71 (1.87)

Yes

No

Approach bias: AN < HC

6

76 HC

14.86 (1.70)

20.42 (2.37)

Neimeijer et al., 2015 [56]

98 AN (64.5% AN, 45.5% EDNOS-AN)

14.97 (1.63)

U

Yes

No

Approach bias high calorie food: pre-treatment < post-treatment

8

Paslaskis et al., 2016 [55]

Approach-avoidance task: participants push or pull computer mouse depending on orientation of on-screen image (horizontal or vertical).

Reaction time on approach versus avoidance trials (approach bias).

41 AN (80.5% R, 19.5% BP)

26.85 (6.71)

15.29 (1.6)

No

Yes

Approach bias: AN < HC

6

42 HC

24.79 (2.71)

21.37 (1.57)

Neuropsychology: Perceptual tasks

Size perception

Yellowlees et al., 1988 [57]

Participants view real food item and adjust screen image to match perceived size.

Estimated versus actual size of items.

20 AN

22.4 (8.0)

U

Yes

No

Size over-estimation: AN > HC

5

20 HC

22.0 (6.6)

Milos et al., 2013 [58]

Participants view meals of different portion sizes.

Estimates of portion size.

24 AN

22.38 (4.10)

15.8 (2.01)

No

Yes

Portion size estimate: AN > HC

7

27 HC

21.41 (2.75)

21.47 (2.71)

Kissileff et al., 2016 [99]

Participants view meals of different portion sizes.

Tolerability and expected anxiety ratings.

24 AN (87.5% R, 22.5% BP)

15.46 (1.57)

17.11 (1.35)

No

No

Portion size tolerability: AN < HC Anticipated anxiety: AN > HC

7

10 HC

14.6 (2.63)

20.6 (1.35)

Weight-gain estimate

Milos et al., 2017 [100]

Participants view meals of different portion sizes. Estimates of weight-gain as a consequence of eating portions presented.

24 AN

22.38 (4.10)

15.8 (2.01)

No

Yes

Estimation of weight-gain: AN > HC

7

27 HC

21.41 (2.75)

21.47 (2.71)

Neuropsychology: Decision making

Food-choice

Steinglass et al., 2015 [60]

Participants select between food items varying in fat content in a binary forced choice task.

Proportion of high fat food items selected.

22 AN (54.5% R, 45.5% BP)

29.4 (11.2)

17.5 (1.9)

No

No

Preference for high-fat food items: AN < HC

6

22 HC

26.3 (5.8)

21.0 (1.7)

Neurophysiology: Attention

Electroencephalography

Blechert et al., 2011 [67]

Neural activity recorded with electroencephalography (EEG) while food images viewed.

Amplitude of neural response.

21 AN

23.2 (4.55)

16.6 (1.3)

Yes

No

Neuronal activity: AN > HC

7

22 BN

26.1 (7.5)

22.6 (3.24)

32 HC

26.2 (5.02)

20.7 (2.41)

Nikendei et al., 2012 [69]

16 AN (81.25% R, 18.25% BP)

22.8 (5.2)

14.8 (2.3)

Yes

No

No differences AN vs HC

8

16 HC pre-meal

23.1 (4.8)

22.3 (2.1)

16 HC post-meal

23.6 (5.2)

20.9 (1.7)

Novosel et al., 2014 [68]

11 AN

15.36 (1.62)

15.79 (1.87)

Yes

No

Neuronal activity: AN > HC

6

11 HC

20.42 (1.77)

Magnetoencephalography

Godier et al., 2016 [33]

Neural activity recorded with magnetoencephalography (MEG) while participants think about how much they want to eat presented food images.

Amplitude of neural response.

13 AN (R)

31.2 (5.3)

15.7 (1.9)

Yes

Yes

Neuronal activity at 150 ms: AN > HC; AN > AN-rec

Neuronal activity at 320 ms: AN < AN-rec

6

14 AN-rec (R)

27.1 (6.5)

20.9 (1.6)

15 HC

23.7 (5.4)

21.4 (1.9)

Neurophysiology: Reward

Electromyography

Soussignan et al., 2010 [71]

Participants view food images presented following subliminal presentation of facial expressions.

Activity of facial (zygomatic, corrugator) muscles index hedonic response.

16 AN (R)

26.68 (7.30)

14.97 (1.97)

No

Yes

Corrugator activity: AN > HC Zygomatic activity: AN < HC

7

25 HC

24.6 (6.03)

20.52 (1.90)

Soussignan et al., 2011 [72]

Participants view food images.

Activity of facial (zygomatic, corrugator) muscles index hedonic response.

17 AN (R)

26.5 (7.1)

14.9 (1.9)

Yes

Yes

Corrugator activity: AN > HC

6

27 HC

24.7 (6.1)

20.4 (1.8)

Hildebrandt et al., 2015 [73]

Participants complete food-based associative learning task.

Activity of facial muscles (zygomatic, corrugator, levator labii), index hedonic and disgust responses.

14 AN/EDNOS-AN (R)

15.05 (1.87)

17.52 (2.91)

No

No

Levator labii activity to food cue: AN > HC

Zygomatic activity to cue for absence of food: AN > HC

5

15 HC

17.64 (2.71)

22.49 (2.94)

Friederich et al., 2006 [74]

Acoustic stimulus and food image presented concurrently; activity of oculomotor muscle recorded.

Startle response indexes appetitive/aversive motivation.

13 AN (84.6% R, 25.4% BP)

25.1 (3.7)

16.4 (3.7)

Yes

Yes

No differences AN vs HC

7

15 BN

25.2 (5.1)

23.4 (3.7)

25 HC

25.0 (3.3)

21.8 (2.7)

Racine et al., 2016 [76]

19 AN (36.8% R, 63.2% BP)

25.11 (9.13)

16.72 (1.63)

Yes

No

AN unable to suppress startle response to food and negative non-food stimuli

7

Erdur et al., 2017 [75]

33 AN (60.6% R, 39.4% BP)

28.2 (9.41)

15.8 (1.90)

Yes

Yes

No differences AN vs AN-rec vs HC

7

15 AN-rec (33.3% R, 66.6% BP)

40.8 (6.79)

20.81 (1.93)

18 HC

28.95 (8.25)

21.82 (1.58)

Neuroimaging

Passive viewing

Nagamitsu et al., 2012 [82]

Participants view images of food stimuli while brain activity measured with functional near infrared spectroscopy.

Neural response.

12 AN (R)

14.4 (1.3)

15.5 (2.0)

Yes

No

No differences AN vs HC

5

13 HC

14.3 (1.3)

18.7 (1.3)

Ellison et al., 1998 [78]

Participants view images of food stimuli while brain activity measured with fMRI.

Neural response.

6 AN

U

15

No

No

Brain activation: AN > HC (insula, anterior cingulate gyrus, amygdala)

6

6 HC

U

Santel et al., 2006 [48]

13 AN (R)

16.1 (2.0)

16.0 (1.7)

Yes

Yes

Brain activation pre-meal: AN < HC (lingual gyrus);

Brain activation post-meal: AN < HC (Inferior parietal lobule)

6

10 HC

16.8 (2.6)

20.5 (1.9)

Gizewski et al., 2010 [47]

12 AN (R)

27 (U)

14.1 (1.8)

Yes

Yes

Brain activation pre-meal: AN > HC (midcingulate cortex); AN < HC (ACC)

Brain activation post-meal: AN > HC (L insula); HC > AN (prefrontal cortex and R insula)

6

10 HC

25 (U)

21.4 (1.5)

Joos et al., 2011 [44]

11 AN (R)

25.0 (5.0)

16.2 (1.2)

Yes

No

Brain activation: AN > HC (amygdala); AN < HC (midcingulum)

6

11 HC

26.0 (5.2)

21.1 (1.8)

Rothemund et al., 2011 [79]

12 AN (83.4% R, 16.6% BP)

24 (6.1)

13.6 (1.2)

Yes

Yes

Brain activation: AN > HC (precuneus)

5

12 HC

26 (3.7)

21 (1.6)

Holsen et al., 2012 [45]

12 AN (R)

21.8 (2.7)

18.0 (0.8)

Yes

Yes

Brain activation pre-meal: AN < HC (amygdala, hypothalamus, insula, hippocampus, orbitofrontal cortex); AN-WR < HC (hypothalamus, amygdala, insula) Brain activation post-meal: AN < HC (insula, amygdala); AN > AN-WR (amygdala); AN < AN-WR (insula)

6

10 AN-WR

23.4 (2.3)

22.1 (2.2)

11 HC

21.6 (1.3)

22.4 (1.3)

Kim et al., 2012 [84]

18 AN (33.3% R, 66.6% BP)

25.2 (4.2)

16.0 (3.7)

Yes

Yes

Brain activation: AN > HC (Inferior frontal gyrus, anterior cingulate cortex, superior frontal gyrus and cerebellem); AN > BN (anterior cingulate cortex); AN < BN (middle temporal gyrus)

6

20 BN

22.9 (3.9)

21.6 (2.3)

20 HC

23.3 (1.8)

19.9 (1.9)

Boehm et al., 2017 [83]

35 AN (94.2% R, 5.8% BP)

16.25 (3.46)

14.59 (1.5)

Yes

No

Brain activation: AN > HC (superior occipital gyrus)

7

25 HC

16.31 (3.39)

20.46 (2.06)

Kerr et al., 2017 [80]

20 AN-WR (R)

17 (3)

18 (3)

Yes

No

Brain activation correlates with interoceptive awareness in opposite directions AN vs HC

5

20 HC

19.84 (0.87)

21.3 (1.55)

Directed food tasks

Uher et al., 2003 [85]

Participants shown images of food while neural activity measured with fMRI; participants instructed to think how hungry images make them feel and whether they would like to eat the food.

Neural response.

8 AN (R)

25.6 (2.8)

16.6 (1.2)

Yes

Yes

Brain activation: AN < AN-rec (Apical prefrontal cortex, dorsolateral prefrontal cortex, medial paracentral cortex, cerebellem); AN > AN-rec (occipital-lingual gyrus)

5

9 AN-rec (R)

26.9 (5.3)

20.4 (2.1)

9 HC

26.6 (3.3)

22.2 (3.8)

Uher et al., 2004 [50]

16 AN (56.8% R, 43.2% BP)

26.93 (12.14)

16.04 (1.64)

Yes

Yes

Brain activation: AN > HC (medial orbitofrontal cortex, lingual gyrus, anterior cingulate); AN < HC (parietal cortex, cerebellem); AN > BN (apical prefrontal cortex, lateral prefrontal cortex, occipital lingual gyrus); AN < BN (cerebellem)

6

10 BN

29.80 (8.80)

22.43 (2.37)

19 HC

26.68 (8.34)

22.41 (2.98)

Brooks et al., 2011 [81]

Participants shown images of food while neural activity measured with fMRI; participants instructed to imagine eating the food.

Neural response.

18 AN (61.1% R, 38.9% BP)

26.0 (6.8)

U

Yes

Yes

Brain activation: AN > BN (parietal lobe, cingulate cortex); AN < BN (superior temporal gyrus, caudate, supplementary motor area); AN > HC (visual cortex); AN < HC (cerebellem)

7

8 BN

25.0 (7.1)

24 HC

26.0 (9.5)

Sanders et al., 2015 [49]

15 AN (60% R, 40% BP)

25.6 (5)

14.5 (1.7)

Yes

Yes

Brain activation: AN < HC (superior frontal gyrus); AN > HC (middle frontal gyrus)

6

15 AN-rec (66.6% R, 33.3% BP)

24.3 (5)

21.1 (1.9)

15 HC

25.8 (5)

21.5 (2.3)

Scaife et al., 2016 [43]

Participants shown images of food while neural activity measured with fMRI; participants instructed to think about how much they want to eat the food at the present moment.

Neural response.

12 AN (R)

29.4 (6)

15.4 (1.9)

No

Yes

Brain activation: AN < HC (postcentral gyrus, precuneus, superior parietal lobule); AN < HC (frontal pole, dorsolateral prefrontal cortex, supramarginal gyrus for low calorie food); AN > HC (frontal pole for high calorie food)

6

14 AN-rec (R)

27 (6.5)

20.9 (1.6)

16 HC

24.3 (5.7)

21.2 (2)

Active choice

Foerde et al., 2015 [61]

Participants select between food items varying in fat content in a binary forced choice task; fMRI measures neural activity.

Neural activity during food choice.

21 AN (47.6% R, 52.4% BP)

26.1 (6.5)

21.5 (1.9)

No

Yes

Brain activation: AN > HC (dorsal striatum)

6

21 HC

22.7 (3.1)

15.7 (2.0)