Delphine Dellacherie

Emotional power of music in patients with memory disorders: clinical implications of cognitive neuroscience.

By adapting methods of cognitive psychology to neuropsychology, we examined memory and familiarity abilities in music in relation to emotion. First we present data illustrating how the emotional content of stimuli influences memory for music. Second, we discuss recent findings obtained in patients with two different brain disorders (medically intractable epilepsy and Alzheimers disease) that show relatively spared memory performance for music, despite severe verbal memory disorders. Studies on musical memory and its relation to emotion open up paths for new strategies in cognitive rehabilitation and reinstate the importance of examining interactions between cognitive and clinical neurosciences.

The effect of musical experience on emotional self-reports and psychophysiological responses to dissonance

To study the influence of musical education on emotional reactions to dissonance, we examined self-reports and physiological responses to dissonant and consonant musical excerpts in listeners with low (LE: n=15) and high (HE: n=13) musical experience. The results show that dissonance induces more unpleasant feelings and stronger physiological responses in HE than in LE participants, suggesting that musical education reinforces aversion to dissonance. Skin conductance (SCR) and electromyographic (EMG) signals were analyzed according to a defense cascade model, which takes into account two successive time windows corresponding to orienting and defense responses. These analyses suggest that musical experience can influence the defense response to dissonance and demonstrate a powerful role of musical experience not only in autonomic but also in expressive responses to music.

Impaired recognition of fear in voices and reduced anxiety after unilateral temporal lobe resection

It has been reported that bilateral amygdala damage in humans compromises the recognition of fear and anger in nonverbal vocalizations (Scott et al., 1997). We addressed the possibility that unilateral temporal lobe damage might be sufficient to impair fear recognition in voices. For this purpose, we tested patients after left (n=10) or right (n=8) medial temporal lobe resection for the relief of intractable epilepsy using a set of nonverbal vocalizations (Belin, Fillion-Bilodeau, & Gosselin, 2008). To focus more narrowly on the role of amygdala subparts, we differentiated patients with complete amygdala damage vs. damage limited to the basolateral complex of the amygdala. The results confirmed for the first time that unilateral amygdala lesion including the basolateral complex can selectively impair recognition of fear and surprise expressed by voices, supporting the notion that the amygdala is a multimodal structure. Interestingly, this impairment was observed in patients with incomplete resection of the amygdala that spared the central nucleus and the corticomedial complex, suggesting that a resection of the basolateral complex is sufficient to affect fear recognition. Given that fear has often been considered as a precursor of anxiety, we also investigated the effect of such lesions on self-reported anxiety. The same patients appeared to be less anxious than control participants in their mood questionnaires. The association of impaired fear perception and decreased anxiety level is considered in the light of recent human and animal data, providing support for a neurobiological basis of mood changes in patients with unilateral temporal lobe damage.

An Intracranial EEG Study of the Neural Dynamics of Musical Valence Processing

The processing of valence is known to recruit the amygdala, orbitofrontal cortex, and relevant sensory areas. However, how these regions interact remains unclear. We recorded cortical electrical activity from 7 epileptic patients implanted with depth electrodes for presurgical evaluation while they listened to positively and negatively valenced musical chords. Time-frequency analysis suggested a specific role of the orbitofrontal cortex in the processing of positively valenced stimuli while, most importantly, Granger causality analysis revealed that the amygdala tends to drive both the orbitofrontal cortex and the auditory cortex in theta and alpha frequency bands, during the processing of valenced stimuli. Results from the current study show the amygdala to be a critical hub in the emotion processing network: specifically one that influences not only the higher order areas involved in the evaluation of a stimuluss emotional value but also the sensory cortical areas involved in the processing of its low-level acoustic features.

Multidimensional scaling of emotional responses to music in patients with temporal lobe resection.

The present study investigated emotional responses to music by using multidimensional scaling (MDS) analysis in patients with right or left medial temporal lobe (MTL) lesions and matched normal controls (NC). Participants were required to evaluate emotional dissimilarities of nine musical excerpts that were selected to express graduated changes along the valence and arousal dimensions. For this purpose, they rated dissimilarity between pairs of stimuli on an eight-point scale and the resulting matrices were submitted to an MDS analysis. The results showed that patients did not differ from NC participants in evaluating emotional feelings induced by the musical excerpts, suggesting that all participants were able to distinguish refined emotions. We concluded that the ability to detect and use emotional valence and arousal when making dissimilarity judgments was not strongly impaired by a right or left MTL lesion. This finding has important clinical implications and is discussed in light of current neuropsychological studies on emotion. It suggests that emotional responses to music can be at least partially preserved at a non-verbal level in patients with unilateral temporal lobe damage including the amygdala.

The birth of musical emotion: a depth electrode case study in a human subject with epilepsy.

Intracranial electroencephalography was recorded in an epileptic patient when he was listening to dissonant and consonant chords and to minor and major chords. Changes in dissonance induced event‐related potentials (ERPs) in the auditory areas from 200 ms onward, in the orbito‐frontal cortex (500–1000 ms), and later in the amygdala and anterior cingulate gyrus (1200–1400 ms), suggesting the sequential involvement of these brain structures in implicit emotional judgment of musical dissonance. Changes in musical mode induced ERPs only in the orbito‐frontal cortex (500–1000 ms), emphasizing the implication of this frontal region in emotional judgment of pleasant music.

Intracranial markers of emotional valence processing and judgments in music

The involvement of the amygdala and orbitofrontal cortex in the processing of valenced stimuli is well established. However, less is known about the extent to which activity in these regions reflects a stimulus’ physical properties, the individual subjective experience it evokes, or both. We recorded cortical electrical activity from five epileptic patients implanted with depth electrodes for presurgical evaluation while they rated “consonant” and “dissonant” musical chords using a “pleasantness” scale. We compared the pattern of responses in the amygdala and orbitofrontal cortex when trials were sorted by pleasantness judgments relative to when they were sorted by the acoustic properties known to influence emotional reactions to musical chords. This revealed earlier differential activity in the amygdala in the physical properties-based, relative to in the judgment-based, analyses. Thus, our results demonstrate that the amygdala has, first and foremost, a high initial sensitivity to the physical properties of valenced stimuli. The finding that differentiations in the amygdala based on pleasantness ratings had a longer latency suggests that in this structure, mediation of emotional judgment follows accumulation of sensory information. This is in contrast to the orbitofrontal cortex where sensitivity to sensory information did not precede differentiation based on affective judgments.

Children and adults with Attention-Deficit/Hyperactivity Disorder cannot move to the beat

Children and adults with Attention-Deficit Hyperactivity Disorder (ADHD) fail in simple tasks like telling whether two sounds have different durations, or in reproducing single durations. The deficit is linked to poor reading, attention, and language skills. Here we demonstrate that these timing distortions emerge also when tracking the beat of rhythmic sounds in perceptual and sensorimotor tasks. This contrasts with the common observation that durations are better perceived and produced when embedded in rhythmic stimuli. Children and adults with ADHD struggled when moving to the beat of rhythmic sounds, and when detecting deviations from the beat. Our findings point to failure in generating an internal beat in ADHD while listening to rhythmic sounds, a function typically associated with the basal ganglia. Rhythm-based interventions aimed at reinstating or compensating this malfunctioning circuitry may be particularly valuable in ADHD, as already shown for other neurodevelopmental disorders, such as dyslexia and Specific Language Impairment.

Emotional memory for musical excerpts in young and older adults.

The emotions evoked by music can enhance recognition of excerpts. It has been suggested that memory is better for high than for low arousing music (Eschrich et al., 2005; Samson et al., 2009), but it remains unclear whether positively (Eschrich et al., 2008) or negatively valenced music (Aubé et al., 2013; Vieillard and Gilet, 2013) may be better recognized. Moreover, we still know very little about the influence of age on emotional memory for music. To address these issues, we tested emotional memory for music in young and older adults using musical excerpts varying in terms of arousal and valence. Participants completed immediate and 24 h delayed recognition tests. We predicted highly arousing excerpts to be better recognized by both groups in immediate recognition. We hypothesized that arousal may compensate consolidation deficits in aging, thus showing more prominent benefit of high over low arousing stimuli in older than younger adults on delayed recognition. We also hypothesized worst retention of negative excerpts for the older group, resulting in a recognition benefit for positive over negative excerpts specific to older adults. Our results suggest that although older adults had worse recognition than young adults overall, effects of emotion on memory do not seem to be modified by aging. Results on immediate recognition suggest that recognition of low arousing excerpts can be affected by valence, with better memory for positive relative to negative low arousing music. However, 24 h delayed recognition results demonstrate effects of emotion on memory consolidation regardless of age, with a recognition benefit for high arousal and for negatively valenced music. The present study highlights the role of emotion on memory consolidation. Findings are examined in light of the literature on emotional memory for music and for other stimuli. We finally discuss the implication of the present results for potential music interventions in aging and dementia.