Sleep and dreaming are for important matters

“…network encompasses a set of connected brain regions that are thought to be typically activated when individuals are engaged in internally-focused tasks including spontaneous cognition, daydreaming, autobiographical memory retrieval, imagination, and introspection (Buckner et al., 2008).”

“It is now well-established that compulsive behaviors may relate to a dysregulation of the hedonic (OFC, insula), emotional (amygdala), and motivational (VTA, NAcc) components of the reward networks (Koob, 2009; Koob and Volkow, 2010).”

“…spindles during NREM sleep have been reported to be associated with memory (procedural and declarative) consolidation and synaptic plasticity processes (Huber et al., 2004; Rosanova and Ulrich, 2005; Marshall et al., 2006; Bergmann et al., 2008; Diekelmann and Born, 2010; Fogel and Smith, 2011).”

“Other reward-related regions, like the ventromedial PFC (vmPFC) and the ACC, which assign a positive or negative value to future outcomes (Takenouchi et al., 1999; Bush et al., 2002; Haber and Knutson, 2010), are activated during REM sleep in humans (Maquet et al., 1996, 2000).”

“Circadian (Wirz-Justice, 2003; Roybal et al., 2007; Li et al., 2013) and neuroendocrine (Schmider et al., 1995; Spiegel et al., 1999; Holsboer, 2000) mechanisms may partially, but not totally subserve a direct causality between sleep disturbances and mood disorders.”

“…are known to produce reward-related and memoryrelated deficits, such as deficits in working memory, episodic memory and executive functioning (Van Dongen et al., 2003; Fortier-Brochu et al., 2012), decreased global emotional intelligence, empathy toward others and quality of interpersonal…”

“…is compatible with other models of reward system such as those focusing on the reinforcementlearning functions of the reward system (Schultz, 2010a), the reward prediction error (Schultz, 1997, 2002; Redgrave et al., 1999; Schultz and Dickinson, 2000) or the ’incentive salience’ (Berridge, 2007).”

“Circadian (Wirz-Justice, 2003; Roybal et al., 2007; Li et al., 2013) and neuroendocrine (Schmider et al., 1995; Spiegel et al., 1999; Holsboer, 2000) mechanisms may partially, but not totally subserve a direct causality between sleep disturbances and mood disorders.”

“…Dongen et al., 2003; Fortier-Brochu et al., 2012), decreased global emotional intelligence, empathy toward others and quality of interpersonal relationships (Killgore et al., 2008), increased aggressiveness (Kamphuis et al., 2012), and negative mood states (Dinges et al., 1997; Zohar et al., 2005).”

“…shares conceptual similarities with Panksepp’s SEEKING system, as it corresponds to the organism’s motivation, behavioral selection, and switching of attention toward reward-related stimuli and is associated mainly with dopaminergic signaling in mesolimbic structures (Berridge et al., 2009).”

“There is accumulating evidence that memory replay and consolidation processes may occur during both REM and NREM sleep in humans (Maquet, 2001; Stickgold, 2005; Diekelmann and Frontiers in Psychology | Consciousness Research July 2013 | Volume 4 | Article 474 | 4 Born, 2010; Oudiette and Paller,…”

“…spindles during NREM sleep have been reported to be associated with memory (procedural and declarative) consolidation and synaptic plasticity processes (Huber et al., 2004; Rosanova and Ulrich, 2005; Marshall et al., 2006; Bergmann et al., 2008; Diekelmann and Born, 2010; Fogel and Smith, 2011).”

“…on the consequences of total sleep deprivation and REM sleep deprivation on emotional and reward functions at the behavioral (Killgore et al., 2006; Banks and Dinges, 2007), neurobiological (Venkatraman et al., 2007; Yoo et al., 2007; Gujar et al., 2011b; Menz et al., 2012) and clinical (Riemann…”

“…is compatible with other models of reward system such as those focusing on the reinforcementlearning functions of the reward system (Schultz, 2010a), the reward prediction error (Schultz, 1997, 2002; Redgrave et al., 1999; Schultz and Dickinson, 2000) or the ’incentive salience’ (Berridge, 2007).”

“Finally, the orexin neurons in the lateral hypothalamus, related to emotional processing and motivated behaviors (Harris et al., 2005; Schwartz et al., 2008; Ponz et al., 2010a,b; Thompson and Borgland, 2011), have occasional burst discharges during REM sleep of rodents (Mileykovskiy et al., 2005;…”

“…on emotional and reward functions at the behavioral (Killgore et al., 2006; Banks and Dinges, 2007), neurobiological (Venkatraman et al., 2007; Yoo et al., 2007; Gujar et al., 2011b; Menz et al., 2012) and clinical (Riemann et al., 2002; Salvadore et al., 2010) levels, we propose here that…”

“…and attentional functions are significantly deactivated compared to the waking state, including the dorsolateral prefrontal cortex (dlPFC), orbitofrontal cortex (OFC), precuneus, and the inferior parietal cortex (Maquet et al., 1996, 2000, 2005; Braun et al., 1997; Nofzinger et al., 1997).”

“…decision-making (aboulia), and in the ability to experience pleasure (anhedonia), are also characteristics of depression (DerAvakian and Markou, 2012), and depict a dysfunction across mesolimbic and non-mesolimbic reward networks (Tremblay et al., 2005; Pizzagalli et al., 2009; Blood et al., 2010).”

“…and attentional functions are significantly deactivated compared to the waking state, including the dorsolateral prefrontal cortex (dlPFC), orbitofrontal cortex (OFC), precuneus, and the inferior parietal cortex (Maquet et al., 1996, 2000, 2005; Braun et al., 1997; Nofzinger et al., 1997).”

“…is selectively activated during self-reflection and attribution of mental states to others, and the medial temporal subsystem (hippocampus-parahippocampus, retrospenial cortex and vmPFC), which is activated during memory retrieval and prospective memory (Buckner et al., 2008; Andrews-Hanna, 2012).”

“Other reward-related regions, like the ventromedial PFC (vmPFC) and the ACC, which assign a positive or negative value to future outcomes (Takenouchi et al., 1999; Bush et al., 2002; Haber and Knutson, 2010), are activated during REM sleep in humans (Maquet et al., 1996, 2000).”

“In addition, sleep can also facilitate insightful behavior because it involves a restructuration of new memory representations (Wagner et al., 2004; Pace-Schott et al., 2012a).”

“Decreased brain perfusion and glucose metabolism in these regions may cause disorientation, illogical thinking, reduced cognitive control, and impaired working memory in dreaming (Hobson et al., 1998, 2000; Schwartz and Maquet, 2002; Schwartz, 2004; Pace-Schott, 2011).”

“Importantly, memory and reward processes may form reciprocal relations, as ML-DA activation is necessary for memory formation and learning (Adcock et al., 2006; Shohamy and Adcock, 2010) (Figure 1B).”

“As depression is also considered as a risk factor for insomnia (Ohayon and Roth, 2003), it has been proposed that the reciprocal links between mood disorders/sleep disturbances form a closed loop (Harvey, 2008).”

“On the other hand, insomnia is a subjective perception of inadequate sleep that represents an independent major risk of subsequent onset of major depression (Ford and Kamerow, 1989; Riemann and Voderholzer, 2003; Johnson et al., 2006; Buysse et al., 2008; Roane and Taylor, 2008).”

“REVIEW ARTICLE published: 25 July 2013 doi: 10.3389/fpsyg.2013.00474 Sleep and dreaming are for important matters”

“This dissociation fits the more general finding that the expression of instinctual emotions and behaviors (e.g. fear and aggressiveness) is more prevalent in REM than NREM dreams (Smith et al., 2004; Wamsley et al., 2007b), which in turn is consistent with substantially larger activation of the amygdala and other limb…”

“Circadian (Wirz-Justice, 2003; Roybal et al., 2007; Li et al., 2013) and neuroendocrine (Schmider et al., 1995; Spiegel et al., 1999; Holsboer, 2000) mechanisms may partially, but not totally subserve a direct causality between sleep disturbances and mood disorders.”

“…in jazz improvisation, has been linked to absence of control from structures that typically mediate conscious volitional control of ongoing performance, like the dlPFC, and simultaneous activation of internally motivated, stimulus-independent behaviors, subserved by the mPFC (Limb and Braun, 2008).”

“…is compatible with other models of reward system such as those focusing on the reinforcementlearning functions of the reward system (Schultz, 2010a), the reward prediction error (Schultz, 1997, 2002; Redgrave et al., 1999; Schultz and Dickinson, 2000) or the ’incentive salience’ (Berridge, 2007).”

“In humans, HC and VS are also activated during NREM sleep (Nofzinger et al., 2002; Peigneux et al., 2004) (see above subsection Neuroimaging Studies).”

“…reward-related and memoryrelated deficits, such as deficits in working memory, episodic memory and executive functioning (Van Dongen et al., 2003; Fortier-Brochu et al., 2012), decreased global emotional intelligence, empathy toward others and quality of interpersonal relationships (Killgore et…”

“…and attentional functions are significantly deactivated compared to the waking state, including the dorsolateral prefrontal cortex (dlPFC), orbitofrontal cortex (OFC), precuneus, and the inferior parietal cortex (Maquet et al., 1996, 2000, 2005; Braun et al., 1997; Nofzinger et al., 1997).”

“Importantly, memory and reward processes may form reciprocal relations, as ML-DA activation is necessary for memory formation and learning (Adcock et al., 2006; Shohamy and Adcock, 2010) (Figure 1B).”

“Conversely, sleep deprivation has deleterious consequences, like increased blood pressure, increased risk for diabetes, obesity, decrease of growth hormones (Van Cauter et al., 2008), and can even be fatal (e.g., in flies and rats) (Rechtschaffen and Bergmann, 2001; Cirelli and Tononi, 2008).”

“On the other hand, insomnia is a subjective perception of inadequate sleep that represents an independent major risk of subsequent onset of major depression (Ford and Kamerow, 1989; Riemann and Voderholzer, 2003; Johnson et al., 2006; Buysse et al., 2008; Roane and Taylor, 2008).”

“…spindles during NREM sleep have been reported to be associated with memory (procedural and declarative) consolidation and synaptic plasticity processes (Huber et al., 2004; Rosanova and Ulrich, 2005; Marshall et al., 2006; Bergmann et al., 2008; Diekelmann and Born, 2010; Fogel and Smith, 2011).”

“In addition, sleep can also facilitate insightful behavior because it involves a restructuration of new memory representations (Wagner et al., 2004; Pace-Schott et al., 2012a).”

“As depression is also considered as a risk factor for insomnia (Ohayon and Roth, 2003), it has been proposed that the reciprocal links between mood disorders/sleep disturbances form a closed loop (Harvey, 2008).”

“While correlations among brain regions of the defaultmode network largely persist during N1 and N2 stages of NREM sleep (Laufs et al., 2007; Horovitz et al., 2008; Larson-Prior et al., 2009), there is evidence for reduced frontal connectivity during SWS (Horovitz et al., 2009; Samann et al., 2011)…”

“…of the recent findings on the consequences of total sleep deprivation and REM sleep deprivation on emotional and reward functions at the behavioral (Killgore et al., 2006; Banks and Dinges, 2007), neurobiological (Venkatraman et al., 2007; Yoo et al., 2007; Gujar et al., 2011b; Menz et al., 2012)…”

“…leads to reduced disappointment in response to losses, together with decreased activity in the insular cortex (Venkatraman et al., 2007), which is thought to process the emotional significance of a stimulus, including the somatic affective response and awareness (Ernst and Paulus, 2005).”

“More recently, Cai et al. (2009) showed that compared with quiet rest and non-REM sleep, REM sleep enhances the integration of initially unassociated information resulting in more creative problem solving.”

“…due to experiencing diverse emotional stimuli during dreaming; the exposure to feared stimuli (objects, situations, thoughts, memories, and physical sensations) in a totally safe context during dreaming may thus resemble desensitization therapy (Perlis and Nielsen, 1993; Levin and Nielsen, 2007).”

“One important function of sleep is memory consolidation, which can be regarded as an open-ended process by which new memories are progressively reorganized and incorporated into preexisting long-term memory networks (Wang and Morris, 2010).”

“Moreover, motor and skill consolidation processes take place predominantly during NREM sleep (Walker et al., 2002a; Stickgold and Walker, 2007) and hippocampal ripples, which prevail during this sleep stage (coupled with the sleep spindles) (Clemens et al., 2011), have been implicated in learning…”

“…is compatible with other models of reward system such as those focusing on the reinforcementlearning functions of the reward system (Schultz, 2010a), the reward prediction error (Schultz, 1997, 2002; Redgrave et al., 1999; Schultz and Dickinson, 2000) or the ’incentive salience’ (Berridge, 2007).”

“By contrast, VTA bursting activity is elevated during REM sleep of rats, up to levels observed during reward and punisher anticipation (Carter et al., 2009) and response to stimulus novelty (Bunzeck and Duzel, 2006; Wittmann et al., 2007; Krebs et al., 2011) at wake.”

“…and attentional functions are significantly deactivated compared to the waking state, including the dorsolateral prefrontal cortex (dlPFC), orbitofrontal cortex (OFC), precuneus, and the inferior parietal cortex (Maquet et al., 1996, 2000, 2005; Braun et al., 1997; Nofzinger et al., 1997).”

“…BOLD responses in the lateral and posterior thalamus, as well as in emotion-related regions such as the anterior cingulate cortex (ACC), insula and superior temporal gyrus; in addition, fast spindles are associated with increased activity in the mPFC and hippocampus (HC) (Schabus et al., 2007).”

“…Dongen et al., 2003; Fortier-Brochu et al., 2012), decreased global emotional intelligence, empathy toward others and quality of interpersonal relationships (Killgore et al., 2008), increased aggressiveness (Kamphuis et al., 2012), and negative mood states (Dinges et al., 1997; Zohar et al., 2005).”

“Slow waves on the other hand are associated with BOLD increases in the inferior frontal gyrus, brainstem, parahippocampal gyrus, precuneus and posterior cingulate cortex during NREM sleep (Dang-Vu et al., 2008).”

“Interestingly, antidepressants that do not suppress REM sleep (e.g., bupropion) (Nofzinger et al., 1995; Ott et al., 2004), have the least risk to induce a hypomanic switch in a depressed person (Leverich et al., 2006).”

“…spindles during NREM sleep have been reported to be associated with memory (procedural and declarative) consolidation and synaptic plasticity processes (Huber et al., 2004; Rosanova and Ulrich, 2005; Marshall et al., 2006; Bergmann et al., 2008; Diekelmann and Born, 2010; Fogel and Smith, 2011).”

“…Dongen et al., 2003; Fortier-Brochu et al., 2012), decreased global emotional intelligence, empathy toward others and quality of interpersonal relationships (Killgore et al., 2008), increased aggressiveness (Kamphuis et al., 2012), and negative mood states (Dinges et al., 1997; Zohar et al., 2005).”

“This off-line replay is induced by HC ripples and may be related to linking a memory trace to a motivational and emotional value during sleep (Lansink et al., 2009; Singer and Frank, 2009; Pennartz et al., 2011).”

“Recent findings suggest that sleep disturbances like insomnia, sleep deprivation and circadian misalignment may developmentally precede and predict early onset of alcohol, cigarette and marijuana use in adolescents and young adults (Roane and Taylor, 2008; Wong et al., 2009; Hasler and Clark, 2013).”

“…supporting this hypothesis, dream content analysis has shown that although past and current waking concerns are common in dreams (Schredl and Hofmann, 2003; Cartwright et al., 2006), dreams are usually novel constructions and rarely reproductions of past events (Fosse et al., 2003; Schwartz, 2003).”

“This off-line replay is induced by HC ripples and may be related to linking a memory trace to a motivational and emotional value during sleep (Lansink et al., 2009; Singer and Frank, 2009; Pennartz et al., 2011).”

“…of the recent findings on the consequences of total sleep deprivation and REM sleep deprivation on emotional and reward functions at the behavioral (Killgore et al., 2006; Banks and Dinges, 2007), neurobiological (Venkatraman et al., 2007; Yoo et al., 2007; Gujar et al., 2011b; Menz et al., 2012)…”

“The phasic VTA dopamine signals during REM sleep (Dahan et al., 2007) may favor an off-line replay of recent emotional memory traces during this sleep stage (Walker and Van Der Helm, 2009).”

“Nightmares would by contrast reflect the failure of fear memory extinction, in the presence of temporary (e.g., daily concerns) or more persistent (e.g., trauma) increases in affect load (Nielsen and Levin, 2007).”

“Indeed, physiological parameters other than those related to specific sleep stages, such as circadian processes (circadian phase), homeostatic processes (duration of prior wakefulness) (Boivin et al., 1997), or others, could be responsible for such modulations.”

“Indeed, an important function of the dopaminergic system is to favor creativity, including associative thinking, innovative insights, cognitive flexibility and divergent thinking (Akbari Chermahini and Hommel, 2010).”

“…and REM sleep deprivation on emotional and reward functions at the behavioral (Killgore et al., 2006; Banks and Dinges, 2007), neurobiological (Venkatraman et al., 2007; Yoo et al., 2007; Gujar et al., 2011b; Menz et al., 2012) and clinical (Riemann et al., 2002; Salvadore et al., 2010)…”

“On the other hand, NREM parasomnias are characterized by a state dissociation, in which two states (wake, sleep) occur simultaneously (Bassetti et al., 2000).”

“…is accumulating evidence that memory replay and consolidation processes may occur during both REM and NREM sleep in humans (Maquet, 2001; Stickgold, 2005; Diekelmann and Frontiers in Psychology | Consciousness Research July 2013 | Volume 4 | Article 474 | 4 Born, 2010; Oudiette and Paller, 2013).”

“…behaviors (e.g. fear and aggressiveness) is more prevalent in REM than NREM dreams (Smith et al., 2004; Wamsley et al., 2007b), which in turn is consistent with substantially larger activation of the amygdala and other limbic regions in REM relative to NREM sleep (Vandekerckhove and Cluydts, 2010).”

“Hypomania and mania have also been causally linked to reduced need for sleep (Wehr et al., 1987; Wehr, 1991; Plante and Winkelman, 2008).”

“…decision-making (aboulia), and in the ability to experience pleasure (anhedonia), are also characteristics of depression (DerAvakian and Markou, 2012), and depict a dysfunction across mesolimbic and non-mesolimbic reward networks (Tremblay et al., 2005; Pizzagalli et al., 2009; Blood et al., 2010).”

“In addition, the HC exhibits a theta rhythm during REM sleep in both animal (Winson, 1972; Popa et al., 2010) and human studies, although human theta activity may be more sporadic and of lower frequency compared to the theta in rodents (Cantero et al., 2003; Clemens et al., 2009).”

“In addition, chronic insomnia is characterized by structural abnormalities of reward-related and memory-related structures such as the OFC (Altena et al., 2010), the HC (Riemann et al., 2007), and the ACC (Plante et al., 2012).”

“Therefore, it seems that emotional, salience and stress networks, subserved by the fear expression (amygdala, ACC), mesolimbic (VTA, NAcc, vmPFC) and extrahypothalamic (extended amygdala) systems respectively, may collaborate or be in opposition during dreaming, according to the emotion/behavior/cognition characterizi…”

“Further supporting this hypothesis, dream content analysis has shown that although past and current waking concerns are common in dreams (Schredl and Hofmann, 2003; Cartwright et al., 2006), dreams are usually novel constructions and rarely reproductions of past events (Fosse et al., 2003;…”

“In addition, the HC exhibits a theta rhythm during REM sleep in both animal (Winson, 1972; Popa et al., 2010) and human studies, although human theta activity may be more sporadic and of lower frequency compared to the theta in rodents (Cantero et al., 2003; Clemens et al., 2009).”

“A disruption of brain reward networks, as well as ineffective emotion regulation processes due to sleep disturbances, could explain the compensatory drug and food seeking in sleep deprived animals (Puhl et al., 2009) and humans (Benedict et al., 2012; Telzer et al., 2013).”

“A disruption of brain reward networks, as well as ineffective emotion regulation processes due to sleep disturbances, could explain the compensatory drug and food seeking in sleep deprived animals (Puhl et al., 2009) and humans (Benedict et al., 2012; Telzer et al., 2013).”

“In humans, HC and VS are also activated during NREM sleep (Nofzinger et al., 2002; Peigneux et al., 2004) (see above subsection Neuroimaging Studies).”

“Sleep deprivation is an objectively measured decrement in sleep, which often has an immediate antidepressant effect in depressed patients (Barbini et al., 1998; Giedke and Schwarzler, 2002).”

“The phasic VTA dopamine signals during REM sleep (Dahan et al., 2007) may favor an off-line replay of recent emotional memory traces during this sleep stage (Walker and Van Der Helm, 2009).”

“This off-line replay is induced by HC ripples and may be related to linking a memory trace to a motivational and emotional value during sleep (Lansink et al., 2009; Singer and Frank, 2009; Pennartz et al., 2011).”

“More specifically, decreases of brain perfusion and brain glucose metabolism in the brainstem, thalamus, basal ganglia, basal forebrain and across several cortical areas including the medial prefrontal cortex (mPFC) and precuneus have been demonstrated (Dang-Vu et al., 2010).”

“In a similar study, (Stickgold et al., 1999) used a semantic priming task and elegantly demonstrated that subjects awoken from REM sleep showed greater priming by weak primes (than by both unrelated primes and strong primes), consistent with a hyperassociative state of the sleeping mind, as also…”

“For example, during NREM sleep, a spontaneous reactivation (replay) of neuronal firing patterns occurs in VS neurons of rats after a reward searching behavior (Pennartz et al., 2004; Lansink et al., 2008).”

“In addition, reward dysfunction in hypomania/mania, at both the neurophysiological (Blumberg et al., 2000; Rubinsztein et al., 2001; Abler et al., 2008) and the phenomenological (increased risk taking, impulsivity) (Mason et al., 2012) levels, is also observed.”

“In sum, these results indicate that REM sleep fosters adapted emotional responses during waking life (Walker and Van Der Helm, 2009) by contributing to overnight emotional and reward brain functions.”

“Hypomania and mania have also been causally linked to reduced need for sleep (Wehr et al., 1987; Wehr, 1991; Plante and Winkelman, 2008).”

“Furthermore, changes in mood after sleep deprivation share several phenomenological similarities with hypomania, and the risk of hypomanic switch is elevated during and after sleep deprivation (Wehr et al., 1982; Colombo et al., 1999).”

“Impaired overnight consolidation of declarative memory is also observed in patients with primary insomnia (Backhaus et al., 2006).”

“By contrast, VTA bursting activity is elevated during REM sleep of rats, up to levels observed during reward and punisher anticipation (Carter et al., 2009) and response to stimulus novelty (Bunzeck and Duzel, 2006; Wittmann et al., 2007; Krebs et al., 2011) at wake.”

“Activity in the NAcc is greatest when uncertainty about outcomes is maximal (Cooper and Knutson, 2008).”

“In addition, it has been proposed that inhibition of supraspinal influence on locomotor centers is an additional condition for NREM parasomnias to occur (Tassinari et al., 2005).”

“It is now well-established that compulsive behaviors may relate to a dysregulation of the hedonic (OFC, insula), emotional (amygdala), and motivational (VTA, NAcc) components of the reward networks (Koob, 2009; Koob and Volkow, 2010).”

“More specifically, studies by Ribeiro and colleagues (Ribeiro et al., 2002; Ribeiro and Nicolelis, 2004) demonstrated an upregulation of the gene zif-268 [related to the expression of long-term potentiation, LTP (Richardson et al., 1992)] in the amygdala, entorhinal, auditory, somatosensory and…”

“This circuit corresponds to the mesolimbic circuits of the SEEKING system, which is a “curiosity-interest-expectancy” command system associated with instinctual appetitive craving states (Panksepp, 1998; Alcaro and Panksepp, 2011).”

“…and attentional functions are significantly deactivated compared to the waking state, including the dorsolateral prefrontal cortex (dlPFC), orbitofrontal cortex (OFC), precuneus, and the inferior parietal cortex (Maquet et al., 1996, 2000, 2005; Braun et al., 1997; Nofzinger et al., 1997).”

“In addition, reward dysfunction in hypomania/mania, at both the neurophysiological (Blumberg et al., 2000; Rubinsztein et al., 2001; Abler et al., 2008) and the phenomenological (increased risk taking, impulsivity) (Mason et al., 2012) levels, is also observed.”

“…in the lateral hypothalamus, related to emotional processing and motivated behaviors (Harris et al., 2005; Schwartz et al., 2008; Ponz et al., 2010a,b; Thompson and Borgland, 2011), have occasional burst discharges during REM sleep of rodents (Mileykovskiy et al., 2005; Takahashi et al., 2008).”

“In addition, the HC exhibits a theta rhythm during REM sleep in both animal (Winson, 1972; Popa et al., 2010) and human studies, although human theta activity may be more sporadic and of lower frequency compared to the theta in rodents (Cantero et al., 2003; Clemens et al., 2009).”

“Furthermore, changes in mood after sleep deprivation share several phenomenological similarities with hypomania, and the risk of hypomanic switch is elevated during and after sleep deprivation (Wehr et al., 1982; Colombo et al., 1999).”

“In addition, reward dysfunction in hypomania/mania, at both the neurophysiological (Blumberg et al., 2000; Rubinsztein et al., 2001; Abler et al., 2008) and the phenomenological (increased risk taking, impulsivity) (Mason et al., 2012) levels, is also observed.”

“…NREM sleep (Walker et al., 2002a; Stickgold and Walker, 2007) and hippocampal ripples, which prevail during this sleep stage (coupled with the sleep spindles) (Clemens et al., 2011), have been implicated in learning and reward processes during sleep (Pennartz et al., 2004; Lansink et al., 2008).”

“This latter observation is consistent with the proposal that REM suppression is one of the main mechanisms by which most antidepressants and sleep deprivation induce hypomanic/manic symptoms (Salvadore et al., 2010).”

“…neuroimaging studies have demonstrated that both NREM and REM sleep may foster lasting neural changes as well as changes in functional connectivity after perceptual, motor, or emotional learning tasks (Schwartz et al., 2002; Maquet et al., 2003; Sterpenich et al., 2007; Payne and Kensinger, 2010).”

“Furthermore, sleep was found to promote the retention and generalization of extinction learning, which could potentially be helpful in generalizing therapeutic extinction learning in exposure therapy (Pace-Schott et al., 2009, 2012b).”

“By contrast, VTA bursting activity is elevated during REM sleep of rats, up to levels observed during reward and punisher anticipation (Carter et al., 2009) and response to stimulus novelty (Bunzeck and Duzel, 2006; Wittmann et al., 2007; Krebs et al., 2011) at wake.”

“Recent findings suggest that sleep disturbances like insomnia, sleep deprivation and circadian misalignment may developmentally precede and predict early onset of alcohol, cigarette and marijuana use in adolescents and young adults (Roane and Taylor, 2008; Wong et al., 2009; Hasler and Clark, 2013).”

“Indeed, a decrease in sleep may trigger a shift toward hypomania/mania in bipolar patients, whereas an increase in sleep can lead to a shift toward depression (Bauer et al., 2006).”

“Further evidence comes from a human study showing that NREM-dependent consolidation of motor skills can be enhanced when it is linked with an anticipation of reward (Fischer and Born, 2009) (but see Tucker et al., 2011).”

“Whether this constitutes a mechanism by which dreams facilitates the resolution of social and emotional conflicts remains to be addressed in future studies (Desseilles et al., 2011).”

“Circadian (Wirz-Justice, 2003; Roybal et al., 2007; Li et al., 2013) and neuroendocrine (Schmider et al., 1995; Spiegel et al., 1999; Holsboer, 2000) mechanisms may partially, but not totally subserve a direct causality between sleep disturbances and mood disorders.”

“Importantly, the predominance of approach behaviors is not incompatible with the high prevalence of negative affect in dreams (Nielsen et al., 1991; Merritt et al., 1994; Revonsuo, 2000), because approach/avoidance behaviors and positive/negative emotions are independent psychological entities that…”

“Further support for the role of REM sleep in LTP processes comes from studies showing that REM sleep deprivation negatively affects LTP in the visual cortex (Shaffery et al., 2002) and in the dorsal HC (Ravassard et al., 2009) of rats.”

“…true that even a minimal misalignment between circadian phase and sleep phase can deteriorate mood (Danilenko et al., 2003), potentially explaining mood-related problems (e.g., irritability) in jet-lag or shift work (Kolla and Auger, 2011), and severity of unipolar depression (Hasler et al., 2010).”

“Further support for the role of REM sleep in LTP processes comes from studies showing that REM sleep deprivation negatively affects LTP in the visual cortex (Shaffery et al., 2002) and in the dorsal HC (Ravassard et al., 2009) of rats.”

“In humans, functional MRI studies have found that REM-dependent enhanced functional connectivity between the amygdala and the mPFC subserve long-lasting consolidation of emotional memories (Sterpenich et al., 2009; Payne and Kensinger, 2011).”

“…of overt behavior in sleep would thus require two concomitant conditions: (a) disinhibition of the central pattern generators of the spinal cord, a condition indispensable for parasomnias (Howell, 2012), and (b) elevated daytime exploratory approach, especially toward a certain kind of stimulus.”

“Amygdala connections with HC, thalamus, the septal nuclei, mPFC and ACC may also have an important role in strengthening affective value associated to memories (Sterpenich et al., 2007, 2009).”

“REVIEW ARTICLE published: 25 July 2013 doi: 10.3389/fpsyg.2013.00474 Sleep and dreaming are for important matters”

“…oriented locomotion in sleepwalking, aggression in REM sleep behavior disorder, sexual behaviors in confusional arousals, and feeding, chewing, or swallowing in the sleep-related eating disorder (SRED) (Morrison et al., 1995; Shapiro et al., 2003; Vetrugno et al., 2006; Winkelman, 2006).”

“Adapted from Perogamvros and Schwartz (2012). www.frontiersin.org July 2013 | Volume 4 | Article 474 | 3 crying) (Oudiette et al., 2009), high motivational value (chewing, swallowing, and sexual behaviors), or even compulsive character (SRED, sleep- related smoking disorder) (Provini et al., 2008).”

“Supplementary evidence that dreaming may be causally related to mesolimbic activation is sparse and mainly comes from pharmacological studies showing that the administration of dopaminergic agents in humans elicits vivid dreams (Balon, 1996; Pinter et al., 1999; Thompson and Pierce, 1999).”

“…an increase in REM density and a reduced REM latency usually precede clinical depression, suggesting that REM sleep, which is under circadian and homeostatic control (Wurts and Edgar, 2000), may constitute a biomarker for depressive disease (Giles et al., 1998; Gottesmann and Gottesman, 2007).”

“…characterized by an increased depressive score in the Hamilton Rating Scale for Depression (McNamara et al., 2010) and an enhanced aversive reactivity toward familiar affective stimuli (Wagner et al., 2002; Lara-Carrasco et al., 2009) [but see also (Gujar et al., 2011a; Van Der Helm et al., 2011)].”

“More specifically, studies by Ribeiro and colleagues (Ribeiro et al., 2002; Ribeiro and Nicolelis, 2004) demonstrated an upregulation of the gene zif-268 [related to the expression of long-term potentiation, LTP (Richardson et al., 1992)] in the amygdala, entorhinal, auditory, somatosensory and…”

“Evidence in favor of this claim comes from the demonstration that mood in REM dreams improves over the course of a night sleep for subjects with pre-sleep depressed mood (Cartwright et al., 1998).”

“…oriented locomotion in sleepwalking, aggression in REM sleep behavior disorder, sexual behaviors in confusional arousals, and feeding, chewing, or swallowing in the sleep-related eating disorder (SRED) (Morrison et al., 1995; Shapiro et al., 2003; Vetrugno et al., 2006; Winkelman, 2006).”

“…supporting this hypothesis, dream content analysis has shown that although past and current waking concerns are common in dreams (Schredl and Hofmann, 2003; Cartwright et al., 2006), dreams are usually novel constructions and rarely reproductions of past events (Fosse et al., 2003; Schwartz, 2003).”

“This off-line replay is induced by HC ripples and may be related to linking a memory trace to a motivational and emotional value during sleep (Lansink et al., 2009; Singer and Frank, 2009; Pennartz et al., 2011).”

“…July 2013 | Volume 4 | Article 474 | 7 Several hypotheses have been formulated to explain this antidepressant effect, including dopaminergic (Ebert and Berger, 1998), noradrenergic (Payne et al., 2002), circadian (Wehr and WirzJustice, 1981), and homeostatic (Endo et al., 1997) mechanisms.”

“Supplementary evidence that dreaming may be causally related to mesolimbic activation is sparse and mainly comes from pharmacological studies showing that the administration of dopaminergic agents in humans elicits vivid dreams (Balon, 1996; Pinter et al., 1999; Thompson and Pierce, 1999).”

“…have been found to relate to distinct facets of daytime affective functioning, such as suicide probability (i.e., frequency of nightmares) (Agargun et al., 2007), protection against depression after divorce (i.e., incorporation of marital status issues) (Cartwright et al., 1984), and…”

“…decision-making (aboulia), and in the ability to experience pleasure (anhedonia), are also characteristics of depression (DerAvakian and Markou, 2012), and depict a dysfunction across mesolimbic and non-mesolimbic reward networks (Tremblay et al., 2005; Pizzagalli et al., 2009; Blood et al., 2010).”

“Two studies have until now demonstrated that dopaminergic neurons in the VTA of rats express an increased bursting activity during REM sleep, inducing a large synaptic dopamine release in the nucleus accumbens (NAcc) shell (Maloney et al., 2002; Dahan et al., 2007).”

“Recent findings suggest that sleep disturbances like insomnia, sleep deprivation and circadian misalignment may developmentally precede and predict early onset of alcohol, cigarette and marijuana use in adolescents and young adults (Roane and Taylor, 2008; Wong et al., 2009; Hasler and Clark, 2013).”

“…spindles during NREM sleep have been reported to be associated with memory (procedural and declarative) consolidation and synaptic plasticity processes (Huber et al., 2004; Rosanova and Ulrich, 2005; Marshall et al., 2006; Bergmann et al., 2008; Diekelmann and Born, 2010; Fogel and Smith, 2011).”

“…Research July 2013 | Volume 4 | Article 474 | 6 Pace-Schott has recently proposed that the activation of the brain’s “default network” during sleep may help explain the expression of social skills and affects during NREM and REM sleep (Pace-Schott, 2007, 2013) (see also Domhoff, 2011).”

“Conversely, sustained cocaine abstinence was shown to cause symptoms of chronic insomnia that may increase the probability for future relapse (Morgan et al., 2006).”

“Sleep deprivation is an objectively measured decrement in sleep, which often has an immediate antidepressant effect in depressed patients (Barbini et al., 1998; Giedke and Schwarzler, 2002).”

“Interestingly, antidepressants that do not suppress REM sleep (e.g., bupropion) (Nofzinger et al., 1995; Ott et al., 2004), have the least risk to induce a hypomanic switch in a depressed person (Leverich et al., 2006).”

“Further support for the role of REM sleep in LTP processes comes from studies showing that REM sleep deprivation negatively affects LTP in the visual cortex (Shaffery et al., 2002) and in the dorsal HC (Ravassard et al., 2009) of rats.”

“…an increase in REM density and a reduced REM latency usually precede clinical depression, suggesting that REM sleep, which is under circadian and homeostatic control (Wurts and Edgar, 2000), may constitute a biomarker for depressive disease (Giles et al., 1998; Gottesmann and Gottesman, 2007).”

“REVIEW ARTICLE published: 25 July 2013 doi: 10.3389/fpsyg.2013.00474 Sleep and dreaming are for important matters”

“REVIEW ARTICLE published: 25 July 2013 doi: 10.3389/fpsyg.2013.00474 Sleep and dreaming are for important matters”

“Both SWS and REM sleep have been linked to emotion regulation processes (Lara-Carrasco et al., 2009; Gujar et al., 2011a; Pace-Schott et al., 2011; Talamini et al., 2013).”

“Decreased brain perfusion and glucose metabolism in these regions may cause disorientation, illogical thinking, reduced cognitive control, and impaired working memory in dreaming (Hobson et al., 1998, 2000; Schwartz and Maquet, 2002; Schwartz, 2004; Pace-Schott, 2011).”

“Positron emission tomography (PET) studies have identified a distinct midline anterior paralimbic area that becomes selectively activated during REM sleep, often to levels similar to or exceeding waking, following the more widespread forebrain deactivation (relative to wakefuness) during NREM sleep (Braun et al., 1998…”

“In this regard, the existing empirical evidence highlighted that the neural activation of emotional-limbic (Nir and Tononi, 2010) and reward systems (Perogamvros and Schwartz, 2012) during REM-DE contributes to the offline reprocessing of emotions and associative learning (Perogamvros et al., 2013).”

“, leading to greater breadth of cognitive associations (Perogamvros et al., 2013).”

“…theories, which suggest that sleep plays an active role in processes such as synaptic plasticity and memory functions, 6–8 emotional regulation, 9–11 metabolic functions and energy balance, 12–17 macromolecule biosynthesis, 18 removal of toxic substances and metabolic waste, 19,20 or…”

“We have previously suggested that these findings from sleep studies may putatively extend to or even depend on concomitant dreaming (Perogamvros et al., 2013; Perogamvros & Schwartz, 2012).”

“It can also produce developmental, cognitive and emotional disorders [4], [3].”

“Though recently there has been some evidence of a move toward a more integrative approach (e.g., Payne, 2010; Perogamvros et al., 2013; Wamsley, 2013, 2014) sleep and dream theories tend to remain relatively disparate.”

“Inevitably, sleep disturbances can dysregulate these motivational and emotional processes and cause predisposition to mood disorders (Perogamvros et al., 2013).”

“Furthermore, sleep appears to afford opportunities for the reorganization of memory networks (22, 65, 71, 72) and thus the integration of newer experiences into pre-existing cortical structures (70, 73–75).”

“Perogamvros et al. (2013) stated that dreams prioritize significant phenomena which have a high value for survival.”

“REM sleep, closely related to cardiovascular regulation, intense emotions and memories [46], is the last stage of the whole five phases in sleep architecture.”

“It is associated with sensory-motor development and learning (1, 2), memory consolidation (3–5), and dreaming (6).”

“Key structures in the mesolimbic system are also activated during sleep and play a vital role in the reprocessing and encoding of memories with high emotional or motivational content (Oishi and Lazarus 2017; Perogamvros and Schwartz 2012; Perogamvros et al. 2013).”

“More recent overview studies support the insight that the contents of dreams are systematically connected with the dreamer ’ s personality and his signi fi cant psychic themes (Perogamvros et al. 2013; Windt 2015).”

“and importance (Wilhelm et al. 2011; Van Dongen et al. 2012; Perogamvros et al. 2013).”

“Thus, the mesolimbic dopaminergic system seems to play an important role in dreaming, both in the dopaminergic forebrain mechanism and in the RAM [13,59–61].”

“There appears to be a general consensus that sleep is important for normal behavior and cognitive function [113].”

“…and FA, seafood is also rich in vitamins, minerals, and some special structures like dopamine hav - ing an important role in brain functions defined as moti - vation, dreaming, sleeping mood, punishment, learning, attention, and memory as stated by Pace-Schott (2010) and Perogamvros et al. (2013).”

“While there may be alternative explanations of the role of dopamine in dreaming (Perogamvros et al., 2013), Hobson’s acceptance of the role of both dopamine and motivation in dreams appears to be endorsing Freud’s fundamental postulate about the motivated nature of dreaming, leading Solms (2013a,…”

“Moreover, a coordinated hippocampal-striatal activity during NREM sleep may contribute to the selective strengthening of memories for important events (Perogamvros et al., 2013).”

“While the effects of dreams on creativity have been observed (e.g. (Klepel et al., 2019)) and reviewed (e.g., (Perogamvros et al., 2013)), the proposed”

“However, many psychoanalysts, psychologists and dream scientists seem to agree that a widely accepted function of dreams is that of emotion regulation (Perogamvros et al., 2013; Roesler, 2023; Zhang et al., 2024).”

“These same structures and pathways are also central to dreaming (Solms, 2000; Perogamvros et al., 2013), suggesting that there is a possible common neurobiological basis underlying the role of dream-related affect in memory consolidation processes.”

“Neuroimaging studies have identi fi ed a distinct midline anterior paralimbic area that becomes selectively activated during REM sleep, often to levels similar to or exceeding waking (25, 27, 28, 41 – 45).”

“In particular, dream contents appear to be connected with important events in waking life (see, e.g., Perogamvros et al., 2013).”

“Developmental, cognitive, and emotional disorders can also result from it [4], [3].”