Motivational and emotional influences on cognitive control in depression: A pupillometry study

Abstract

Depressed people perform poorly on cognitive tasks; however, under certain conditions they show intact cognitive performance, with physiological reactivity consistent with needing to recruit additional cognitive control. We hypothesized that this apparent compensation is driven by the presence of affective processes (e.g., state anxiety), which in turn are moderated by the depressed individual's motivational state. Clarifying these processes may help researchers identify targets for treatment that if addressed may improve depressed patients' cognitive functioning. To test this hypothesis, 36 participants with unipolar depression and 36 never-depressed controls completed a problem-solving task that was modified to elicit anxiety. The participants completed measures of motivation, anxiety, sadness, and rumination, while pupillary responses were continuously measured during problem-solving, as an index of cognitive control. Anxiety increased throughout the task for all participants, whereas both sadness and rumination were decreased during the task. In addition, anxiety more strongly affected planning accuracy in depressed participants than in controls, regardless of the participants' levels of motivation. In contrast, differential effects of anxiety on pupillary responses were observed as a function of depressed participants' levels of motivation. Consistent with the behavioral results, less-motivated and anxious depressed participants demonstrated smaller pupillary responses, whereas more highly motivated and anxious depressed participants demonstrated larger pupillary responses than did controls. Strong effects of sadness and rumination on cognitive control in depression were not observed. Thus, we conclude that anxiety inhibits the recruitment of cognitive control in depression and that a depressed individual's motivational state determines, in part, whether he or she is able to compensate by recruiting additional cognitive control.

Figures

Fig. 1

Modified computer version of the Tower of London.

Fig. 2

Between group differences and changes in motivation, anxiety, sadness, and rumination at baseline and across task blocks. Bars with differing letters within an effect are significantly different from one another.

Fig. 3

The top and bottom panels shows the decomposition of the anxiety-by-clinical status and motivation-by-sadness-by-clinical status interactions on planning accuracy. The panels show (A) the simple slopes for the effect of anxiety on planning accuracy as a function of clinical status (never-depressed controls vs. unipolar depressed); (B) the differences in planning accuracy at high levels of anxiety as a function of clinical status; (C) the simple slopes for the effect of sadness on planning accuracy as a function of clinical status at low levels of motivation; (D) the differences in planning accuracy at high levels of sadness as a function of clinical status and motivation; (E) the simple slopes for the effect of sadness on planning accuracy as a function of clinical status at high levels of motivation.

Fig. 4

Pupil dilation in response to increasing levels of task load during the Tower of London separated by the type of pupilometer. The red bar under each pupil dilation waveform reflects where the omnibus test of differences in task-load at each time-point is statistically significant at p< 0.05. Black underlined segments indicate regions that are statistical significant after controlling for multiple comparisons.

Fig. 5

The top and bottom panels shows the decomposition of the significant motivation-by-emotion-by-clinical status interactions on pupil dilation. The panels show (A) the simple slopes for the effect of anxiety on pupil dilation as a function of clinical status (never-depressed controls vs. unipolar depressed) at low levels of motivation; (B) the differences in pupil dilation at high levels of anxiety as a function of clinical status and motivation; (C) the simple slopes for the effect of anxiety on pupil dilation as a function of clinical status at high levels of motivation; (D) the simple slopes for the effect of sadness on pupil dilation as a function of clinical status at low levels of motivation; (E) the differences in pupil dilation at high levels of sadness as a function of clinical status and motivation; (F) the simple slopes for the effect of sadness on pupil dilation as a function of clinical status at high levels of motivation.