Differential effects of indoleamines on auditory choice reaction, selective attention, and pitch discrimination

Impaired pitch identification as a potential marker for depression

BACKGROUND

Impaired auditory performance has been considered as marker for depression. The present study tested whether pitch perception is affected in depression and whether the impairment is task-specific or reflects global dysfunction.

METHODS

Twelve depressive in-patients and 12 non-depressive participants, half of the sample women, volunteered. The participants performed pitch identification using a four-choice reaction task, pitch contour perception, and pitch discrimination.

RESULTS

During pitch identification but not during pitch contour perception or pitch discrimination, depressive patients responded less accurate than non-depressive participants (F = 3.3, p = 0.047). An analysis of covariates revealed that only female but not male depressive patients identified pitches poorly (Z = -2.2, p = 0.025) and inaccurate pitch identification correlated with high scores in the Beck Depression Inventory in women (r = -0.8, p = 0.001) but not in men (r = -0.1, p = 0.745). Patients did not differ from controls in reaction time or responsiveness.

CONCLUSIONS

Impaired pitch perception in depression is task-specific. Therefore, cognitive deficits in depression are circumscribed and not global. Reduced pitch identification in depression was associated with female sex. We suggest that impaired pitch identification merits attention as a potential marker for depression in women.

Numeric aspects in pitch identification: an fMRI study

Background

Pitch identification had yielded unique response patterns compared to other auditory skills. Selecting one out of numerous pitches distinguished this task from detecting a pitch ascent. Encoding of numerous stimuli had activated the intraparietal sulcus in the visual domain. Therefore, we hypothesized that numerosity encoding during pitch identification activates the intraparietal sulcus as well.

Methods

To assess pitch identification, the participants had to recognize a single pitch from a set of four possible pitches in each trial. Functional magnetic resonance imaging (fMRI) disentangled neural activation during this four-pitch-choice task from activation during pitch contour perception, tone localization, and pitch discrimination.

Results

Pitch identification induced bilateral activation in the intraparietal sulcus compared to pitch discrimination. Correct responses in pitch identification correlated with activation in the left intraparietal sulcus. Pitch contour perception activated the superior temporal gyrus conceivably due to the larger range of presented tones. The differentiation between pitch identification and tone localization failed. Activation in an ACC-hippocampus network distinguished pitch discrimination from pitch identification.

Conclusion

Pitch identification is distinguishable from pitch discrimination on the base of activation in the IPS. IPS activity during pitch identification may be the auditory counterpart of numerosity encoding in the visual domain.

The bright side of being blue: depression as an adaptation for analyzing complex problems

Depression is the primary emotional condition for which help is sought. Depressed people often report persistent rumination, which involves analysis, and complex social problems in their lives. Analysis is often a useful approach for solving complex problems, but it requires slow, sustained processing, so disruption would interfere with problem solving. The analytical rumination hypothesis proposes that depression is an evolved response to complex problems, whose function is to minimize disruption and sustain analysis of those problems by (a) giving the triggering problem prioritized access to processing resources, (b) reducing the desire to engage in distracting activities (anhedonia), and (c) producing psychomotor changes that reduce exposure to distracting stimuli. As processing resources are limited, sustained analysis of the triggering problem reduces the ability to concentrate on other things. The hypothesis is supported by evidence from many levels-genes, neurotransmitters and their receptors, neurophysiology, neuroanatomy, neuroenergetics, pharmacology, cognition, behavior, and efficacy of treatments. In addition, the hypothesis provides explanations for puzzling findings in the depression literature, challenges the belief that serotonin transmission is low in depression, and has implications for treatment.

Differential skills of perception of frequency

This study aimed to develop tests for differentiating auditory perception skills, e.g., to test drug effects. In Exp. 1 (N = 60), discrimination of succeeding frequencies, frequency identification assessed by a choice reaction task, and the perception of pitch contour assessed by frequency deviants in binaural melodies showed zero partial correlations. In Exp. 2 (N = 36), discrimination correlated with performance on a field dependence test; fast frequency identification correlated with verbal fluency. The auditory tests are likely suitable for assessing distinct skills, but correlations with general cognitive abilities require further investigations.