Dopaminergic system and dream recall: An MRI study in Parkinson's disease patients

Abstract

We investigated the role of the dopamine system [i.e., subcortical-medial prefrontal cortex (mPFC) network] in dreaming, by studying patients with Parkinson's Disease (PD) as a model of altered dopaminergic transmission. Subcortical volumes and cortical thickness were extracted by 3T-MR images of 27 PD patients and 27 age-matched controls, who were asked to fill out a dream diary upon morning awakening for one week. PD patients do not substantially differ from healthy controls with respect to the sleep, dream, and neuroanatomical measures. Multivariate correlational analyses in PD patients show that dopamine agonist dosage is associated to qualitatively impoverished dreams, as expressed by lower bizarreness and lower emotional load values. Visual vividness (VV) of their dream reports positively correlates with volumes of both the amygdalae and with thickness of the left mPFC. Emotional load also positively correlates with hippocampal volume. Beside the replication of our previous finding on the role of subcortical nuclei in dreaming experience of healthy subjects, this represents the first evidence of a specific role of the amygdala-mPFC dopaminergic network system in dream recall. The association in PD patients between higher dopamine agonist dosages and impoverished dream reports, however, and the significant correlations between VV and mesolimbic regions, however, provide an empirical support to the hypothesis that a dopamine network plays a key role in dream generation. The causal relation is however precluded by the intrinsic limitation of assuming the dopamine agonist dosage as a measure of the hypodopaminergic state in PD. Periodicals, Inc.

Spotlight on dream recall: the ages of dreams

“…Visual vividness has been found to positively correlate with the volume of amygdala and the thickness of the left medial prefrontal cortex (mPFC) in PD patients, while emotional load is positively correlated with hippocampal volume, suggesting a role of amygdala–mPFC dopaminergic network system in dream recall. 88 This partly supports the hypothesis of a role of paralimbic structures in the access and processing of dream contents. 43 According to this hypothesis, emotional salience of dream imagery is due to the activation of the paralimbic cortices by the amygdala, 87 , 88 while bizarreness of dream contents is a consequence of prefrontal deactivation, reducing the higher order control on the amygdalar and hippocampal functioning.…”

“… 88 This partly supports the hypothesis of a role of paralimbic structures in the access and processing of dream contents. 43 According to this hypothesis, emotional salience of dream imagery is due to the activation of the paralimbic cortices by the amygdala, 87 , 88 while bizarreness of dream contents is a consequence of prefrontal deactivation, reducing the higher order control on the amygdalar and hippocampal functioning. 110 It is well known that the amygdala and the hippocampal formation shows a relatively high metabolic activity during sleep.…”

“… 27 Consequently, the most used method in children’s dream research is the exclusive collection of dream reports. 5 , 67 – 69 On one hand, it should be considered that the content analysis methods are widely defined in literature, 16 , 44 , 45 , 85 – 88 while, on the other hand, the presence of different methods for collecting dream reports in children leads to additional biases, when a comparison with content analysis in adulthood is requested. 69 In fact, dream reports are more often collected at home by a caregiver instead of being reported to the researcher or directly by the child, which potentially misleads the actual dream content.…”

Apical drive—A cellular mechanism of dreaming?

“…has been implicated in sleep regulation, dreaming, and dream recall by some authors (e.g. Gottesmann, 2002;De Gennaro et al, 2016;Solms, 1997, Solms, 2000. DA release is known to be high in wakefulness, in particular in prefrontal cortex ( Table 1; Miller et al, 1983;Trulson et al, 1984;Maloney et al 2001), and some studies suggest that DA release is higher in REM than in NREM sleep (Lena et al 2005), but others reported little difference between wake and sleep states (Miller et al, 1983;Trulson et al, 1984).…”

<p>Electrophysiological Correlates of Dream Recall During REM Sleep: Evidence from Multiple Awakenings and Within-Subjects Design</p>

“…In this respect, neuroimaging studies revealed that volumetric and structural measures of brain networks, such as the amygdala and hippocampus, were related to specific qualitative characteristics of dream reports. 16,17 Moreover, Eichenlaub et al 18 observed that the activation of the temporo-parietal-junction and the medial prefrontal cortex was associated with higher DR frequency.…”