Dietary linoleic acid supplementation protects against obesity-induced microglial reactivity in mice.

We investigated whether linoleic acid (LA) supplementation could modulate emotional behavior and microglia-related neuroinflammation. For that, male mice of C57BL/6J genetic background fed either a high-fat diet (HFD) or a standard diet (STD) for 12 weeks, were treated with a vehicle or LA solution for 5 weeks before being evaluated for emotional behavior using a battery of behavioral tests. The animals were subsequently sacrificed and their brains collected and processed for immunofluorescence staining, targeting microglia-specific calcium-binding proteins (IBA-1). Neuroinflammation severity was assessed in multiple hypothalamic, cortical and subcortical brain regions. We show an anxio-depressive-like effect of sustained HFD feeding that was neither alleviated nor worsened with LA supplementation. However, increased IBA-1 expression and microgliosis in the HFD group were largely attenuated by LA supplementation. These observations demonstrate that the anti-neuroinflammatory properties of LA are not restricted to hypothalamic areas but are also evident at the cortical and subcortical levels. This study discloses that neuroinflammation plays a role in the genesis of neuropsychiatric disorders in the context of obesity, and that LA supplementation is a useful dietary strategy to alleviate the impact of obesity-related neuroinflammation.

Predictors of Gaming Disorder or Protective from It, in a French Sample: A Symptomatic Approach to Self-Regulation and Pursued Rewards, Providing Insights for Clinical Practice.

Gaming disorder (GD) is a new health condition still requiring a lot of evidence established around its underlying and related psychological mechanisms. In our study we focused on Massively Multiplayer Online Role Playing Games (MMORPGs), a specific very popular and engaging game genre, to determine that benefit, motivation and control aspects could be predictive of a dysfunctional engagement in gaming. In total, 313 participants were recruited from private forums of gamers between May 2009 and March 2010. They filled out a questionnaire on their socio-demographic data and their weekly gaming time. They also completed different psychometric assessments such as the DSM IV-TR criteria for substance dependence adapted to gaming such as the Dependence Adapted Scale (DAS), the external rewards they expected from gaming (External Motives), the expected internal reward they expected from gaming (Internal Motives), the Zuckerman Sensation Seeking Scale (ZSSS), and the Barratt impulsiveness Scale (BIS-10). Results showed that some psychological factors related to online gaming represented risk factors for GD in participants (i.e., competition and advancement motives, reduced anxiety, solace, greater personal satisfaction, and sense of power), whereas some others were found to be protective factors from GD (i.e., recreation, enjoyment and experience seeking) in participants. Additionally, the study found that disinhibition, boredom susceptibility, thrill and adventure seeking, and high impulsivity were correlated to GD in participants. In conclusion, not only motives for gaming and impulsivity could be predictors for GD, but maladaptive coping strategies based on experienced relief in-game from negative feelings (anxiety and boredom) or experienced improvement in-game of self-perception (personal satisfaction, sense of power) could play as well a role of negative reinforcers for GD. Some benefits from gaming, typically entertainment and enjoyment, are shown to be protective factors from GD, playing the role of positive reinforcing factors. They are worthy of being identified and promoted as functional gaming habits. These findings can feed the clinical and health promotion fields, with a more in-depth understanding of diverse psychological factors in gamers, identifying those at risk for GD and those protective from it. The current work can foster a more balanced approach towards gaming activities, taking their opportunities for mankind and controlling for their adverse effects in some individuals.

Beneficial effects of prolonged 2-phenylethyl alcohol inhalation on chronic distress-induced anxio-depressive-like phenotype in female mice.

Chronic distress-induced hypothalamic-pituitary-adrenal axis deregulations have been associated with the development of neuropsychiatric disorders such as anxiety and depression. Currently available drugs treating such pathological conditions have limited efficacy and diverse side effects, revealing the need of new safer strategies. Aromatic plant-based compounds are largely used in herbal medicine due to their therapeutic properties on mood, physiology, and general well-being. The purpose of this study was to investigate the effects of 2-phenylethyl alcohol (PEA), one of the pharmacologically active constituents of rose essential oil, on chronic corticosterone (CORT)-induced behavioral and neurobiological changes in female mice. Animals followed a prolonged PEA inhalation exposure (30 min per day) for 15 consecutive days prior to behavioral evaluation with open-field, forced swim and novelty-suppressed feeding tests. CORT treatment induced an anxio-depressive-like phenotype, evidenced by a reduced locomotor activity in the open-field, and an increased latency to feed in the novelty-suppressed feeding paradigms. To elucidate the neural correlates of our behavioral results, immunohistochemistry was further performed to provide a global map of neural activity based on cerebral cFos expression. The altered feeding behavior was accompanied by a significant decrease in the number of cFos-positive cells in the olfactory bulb, and altered functional brain connectivity as shown by cross-correlation-based network analysis. CORT-induced behavioral and neurobiological alterations were reversed by prolonged PEA inhalation, suggesting a therapeutic action that allows regulating the activity of neural circuits involved in sensory, emotional and feeding behaviors. These findings might contribute to better understand the therapeutic potential of PEA on anxio-depressive symptoms.

Validity and Usage of the Seasonal Pattern Assessment Questionnaire (SPAQ) in a French Population of Patients with Depression, Bipolar Disorders and Controls.

The Seasonal Pattern Assessment Questionnaire (SPAQ), by Rosenthal et al. (1984), is by far the most used questionnaire to evaluate seasonal effects on mood and behavior. It includes a general seasonality score (GSS), composed of 6 items, from which cutoffs have been established to screen for seasonal affective disorder (SAD). However, it has never been validated in French and associations with circadian rhythm and symptoms of depression and bipolarity remain unclear. In this study, including 165 subjects (95 controls and 70 patients with depression or bipolar disorder), we confirmed the validity of the French version of the SPAQ, with a two-factor structure (a psychological factor: energy, mood, social activity and sleep length; and a food factor: weight and appetite) and a good fit was observed by all indicators. Mood and social activity dimensions were significantly affected by seasons in the depressed/bipolar group and a stronger global seasonality score (GSS) was associated with more severe phenotypes of depression and mania. Subjects meeting SAD and subsyndromal-SAD criteria also showed a delayed circadian rhythm compared to controls. Simple tools, such as the SPAQ, can aid the identification of significant seasonal changes and have direct implications on therapeutics including the use of bright light therapy in order to enhance personalized treatments, but also to prevent adverse seasonal effects.

Evidence for a neural signature of musical preference during silence.

One of the most basic and person-specific affective responses to music is liking. The present investigation sought to determine whether liking was preserved during spontaneous auditory imagery. To this purpose, we inserted two-second silent intervals into liked and disliked songs, a method known to automatically recreate a mental image of these songs. Neural correlates of musical preference were measured by high-density electroencephalography in twenty subjects who had to listen to a set of five pre-selected unknown songs the same number of times for two weeks. Time frequency analysis of the two most liked and the two most disliked songs confirmed the presence of neural responses related to liking. At the beginning of silent intervals (400-900 ms and 1000-1300 ms), significant differences in theta activity were originating from the inferior frontal and superior temporal gyrus. These two brain structures are known to work together to process various aspects of music and are also activated when measuring liking while listening to music. At the end of silent intervals (1400-1900 ms), significant alpha activity differences originating from the insula were observed, whose exact role remains to be explored. Although exposure was controlled for liked and disliked songs, liked songs were rated as more familiar, underlying the strong relationship that exists between liking, exposure, and familiarity.

Transcranial direct current stimulation produces long-lasting attenuation of cocaine-induced behavioral responses and gene regulation in corticostriatal circuits.

Transcranial direct current stimulation (tDCS) is a non-invasive method to modulate cortical excitability. This technique is a promising emerging tool to treat several neuropathologies, including addiction. We have previously shown in mice that repeated tDCS normalizes pathological behaviors associated with chronic nicotine exposure. Here, we evaluated, in adult female mice, the impact of tDCS on cocaine-induced behavior and gene regulation in corticostriatal circuits implicated in psychostimulant addiction. Anodal tDCS was applied transcranially over the frontal cortex. Three weeks after repeated tDCS, we investigated the induction of a gene expression marker (Zif268) by cocaine (25 mg/kg) in 26 cortical and 23 striatal regions using in situ hybridization histochemistry. We also assessed place preference conditioning by cocaine (5, 10 and 25 mg/kg). tDCS pretreatment increased basal expression and attenuated cocaine (25 mg/kg)-induced expression of Zif268 in specific corticostriatal circuits. Cocaine-induced locomotor activation (25 mg/kg) and place preference conditioning (5 and 25 mg/kg) were also reduced. These results demonstrate that tDCS can attenuate molecular and behavioral responses to cocaine for several weeks. Together, our findings provide pre-clinical evidence that such electrical brain stimulation may be useful to modify the psychostimulant addiction risk.

Don't forget the lyrics! Spatiotemporal dynamics of neural mechanisms spontaneously evoked by gaps of silence in familiar and newly learned songs.

The vast majority of people experience musical imagery, the sensation of reliving a song in absence of any external stimulation. Internal perception of a song can be deliberate and effortful, but also may occur involuntarily and spontaneously. Moreover, musical imagery is also involuntarily used for automatically completing missing parts of music or lyrics from a familiar song. The aim of our study was to explore the onset of musical imagery dynamics that leads to the automatic completion of missing lyrics. High-density electroencephalography was used to record the cerebral activity of twenty healthy volunteers while they were passively listening to unfamiliar songs, very familiar songs, and songs previously listened to for two weeks. Silent gaps inserted into these songs elicited a series of neural activations encompassing perceptual, attentional and cognitive mechanisms (range 100-500ms). Familiarity and learning effects emerged as early as 100ms and lasted 400ms after silence occurred. Although participants reported more easily mentally imagining lyrics in familiar rather than passively learnt songs, the onset of neural mechanisms and the power spectrum underlying musical imagery were similar for both types of songs. This study offers new insights into the musical imagery dynamics evoked by gaps of silence and on the role of familiarity and learning processes in the generation of these dynamics. The automatic and effortless method presented here is a potentially useful tool to understand failure in the familiarity and learning processes of pathological populations.

[Other therapeutic strategies]. / Dépression résistante : les autres stratégies thérapeutiques.

Non-selective and irreversible MAOI have become as third or fourth-line strategy for the management of treatment-resistant depression. Non-selective and irreversible MAOI requires careful monitoring of drug interactions and dietary restrictions. Nutritional supplements such as omega-3 have been found to produce beneficial effects in the management of treatment-resistant depression when administered in combination with the ongoing antidepressant treatment. The glutamate antagonist ketamine has been found to produce beneficial effects in the management of treatment-resistant depression while administered alone. Dopamine and/or norepinephrine agonists, such as methylphenidate, modafinil or pramipexole, have been found to produce beneficial effects in the management of treatment-resistant depression when administered in combination with the ongoing antidepressant treatment.

Motor imagery in unipolar major depression.

BACKGROUND: Motor imagery is a potential tool to investigate action representation, as it can provide insights into the processes of action planning and preparation. Recent studies suggest that depressed patients present specific impairment in mental rotation. The present study was designed to investigate the influence of unipolar depression on motor imagery ability. METHODS: Fourteen right-handed patients meeting DSM-IV criteria for unipolar depression were compared to 14 matched healthy controls. Imagery ability was accessed by the timing correspondence between executed and imagined movements during a pointing task, involving strong spatiotemporal constraints (speed/accuracy trade-off paradigm). RESULTS: Compared to controls, depressed patients showed marked motor slowing on both actual and imagined movements. Furthermore, we observed greater temporal discrepancies between actual and mental movements in depressed patients than in healthy controls. Lastly, depressed patients modulated, to some extent, mental movement durations according to the difficulty of the task, but this modulation was not as strong as that of healthy subjects. CONCLUSION: These results suggest that unipolar depression significantly affects the higher stages of action planning and point out a selective decline of motor prediction.

Massively multiplayer online role-playing games: comparing characteristics of addict vs non-addict online recruited gamers in a French adult population.

BACKGROUND: Massively Multiplayer Online Role-Playing Games (MMORPGs) are a very popular and enjoyable leisure activity, and there is a lack of international validated instruments to assess excessive gaming. With the growing number of gamers worldwide, adverse effects (isolation, hospitalizations, excessive use, etc.) are observed in a minority of gamers, which is a concern for society and for the scientific community. In the present study, we focused on screening gamers at potential risk of MMORPG addiction. METHODS: In this exploratory study, we focused on characteristics, online habits and problematic overuse in adult MMORPG gamers. In addition to socio-demographical data and gamer behavioral patterns, 3 different instruments for screening addiction were used in French MMORPG gamers recruited online over 10 consecutive months: the substance dependence criteria for the Diagnostic and Statistical Manual of Mental Disorder, fourth revised edition (DSM-IV-TR) that has been adapted for MMORPG (DAS), the qualitative Goldberg Internet Addiction Disorder scale (GIAD) and the quantitative Orman Internet Stress Scale (ISS). For all scales, a score above a specific threshold defined positivity. RESULTS: The 448 participating adult gamers were mainly young adult university graduates living alone in urban areas. Participants showed high rates of both Internet addiction (44.2% for GIAD, 32.6% for ISS) and DAS positivity (27.5%). Compared to the DAS negative group, DAS positive gamers reported significantly higher rates of tolerance phenomenon (increased amount of time in online gaming to obtain the desired effect) and declared significantly more social, financial (OR: 4.85), marital (OR: 4.61), family (OR: 4.69) and/or professional difficulties (OR: 4.42) since they started online gaming. Furthermore, these gamers self-reported significantly higher rates (3 times more) of irritability, daytime sleepiness, sleep deprivation due to play, low mood and emotional changes since online gaming onset. CONCLUSIONS: The DAS appeared to be a good first-line instrument to screen MMORPG addiction in online gamers. This study found high MMORPG addiction rates, and self-reported adverse symptoms in important aspects of life, including mood and sleep. This confirms the need to set up relevant prevention programs against online game overuse.