The serotonin 5-HT1A receptor agonist tandospirone improves executive function in common marmosets

Side effects and cognitive benefits of buspirone: A systematic review and meta-analysis

Buspirone, a 5-hydroxytryptamine 1A (5-HT1A) receptor agonist, has been investigated for its use in various diseases. However, knowledge about its side effects and potential cognitive benefits in different conditions is limited. Cognitive impairment is also a prevalent symptom in many diseases, yet effective treatments are still lacking. Therefore, to explore the potential side effects of buspirone and the possible cognitive benefits of buspirone, we conducted a comprehensive search of several databases, including PubMed, Embase, Web of Science, Cochrane Review, Cochrane Trial, and ClinicalTrials.gov, to identify eligible randomized clinical trials. Our primary outcome measures included both side effects (adverse events) and cognitive benefits. For continuous variables, we utilized effect size with a 95% confidence interval (CI), whereas for dichotomous variables, we used odds ratios (OR) with a 95% CI. In total, 16 studies were included in this analysis, with 13 studies reporting on buspirone's side effects and 4 studies focusing on cognitive tasks. In terms of side effects, buspirone exhibited a higher rate of dizziness (OR = 4.66, 95% CI: 2.07-10.47), constipation (OR = 4.11, 95% CI: 1.34-12.55), and gastric distress (OR = 1.97, 95% CI: 1.03-3.78) than the placebo group. Regarding cognitive functions, buspirone showed significant benefits (g = 0.20, 95% CI: 0.06-0.34) while the placebo did not. Subgroup analysis indicated superior performance in visual learning and memory (g = 0.49, 95% CI: 0.21-0.78), logical reasoning (g = 0.42, 95% CI: 0.14-0.71), and attention (g = 0.37, 95% CI: 0.13-0.61) when compared to placebo. Our findings indicated that participants in the buspirone group experienced side effects of dizziness, constipation, and gastric distress in different diseases. Despite these adverse events, however, buspirone demonstrated significant cognitive benefits, particularly in the domains of visual learning and memory, logical reasoning, and attention.

Augmentation therapy with tandospirone citrate in vascular depression patients with mild cognitive impairment: A prospective randomized clinical trial

Cognitive impairment is a prominent clinical manifestation of vascular depression (VaDep). The current study aimed to assess the efficacy of tandospirone citrate in VaDep cases with mild cognitive impairment (VaDep-MCI) as well as the role of plasma monoamine neurotransmitters during the treatment. In this single-blind, randomized controlled study, 116 participants were randomly assigned to the tandospirone (tandospirone citrate-escitalopram) and control (escitalopram) groups. The primary endpoints were changes in cognitive test scores from baseline to Week 8, including the Rey Auditory Verbal Learning Test (RAVLT), Semantic Verbal Fluency (SVF) test, Trail Making Test (TMT), Digital Span Test (DST) and Clock Drawing Test (CDT) scores. Generalized estimating equation models were used to examine repeated measures. The results showed that compared with the changes in the control group from baseline to Week 8, the tandospirone group showed more significant changes in SVF score at Weeks 4 (p < 0.05) and 8 (p < 0.001), and TMT (B-A) score at Week 8 (p < 0.05). RAVLT, DST and DCT scores were relatively stable in both groups during the study period. Moreover, mediation analysis showed that these results were not mediated by the alleviation of depression symptoms. Partial Spearman correlation analysis showed that only plasma 5-hydroxytryptamine (5-HT) was positively correlated with Hamilton Depression Rating Scale score after Bonferroni correction (r = 0.347, p < 0.001). Augmentation therapy with tandospirone citrate improved the executive and language functions of VaDep-MCI patients. Additionally, plasma 5-HT levels may serve as a potential biomarker of VaDep severity. These findings may provide clinical insights into the treatment of vascular depression.

Decreased 5-HT1A binding in mild Alzheimer's disease - a PET study

INTRODUCTION

Decreased 5-HT_1A receptor binding has been associated with Alzheimer's disease (AD) and interpreted as a consequence of neuron loss. The purpose of the present study was to compare [¹¹ C]WAY100635 binding to the 5-HT_1A receptor in hippocampus, entorhinal cortex, amygdala and pericalcarine cortex in mild AD patients and elderly controls.

METHODS

AD patients (n = 7) and elderly control subjects (n = 8) were examined with positron emission tomography (PET) and [¹¹ C]WAY100635. PET data acquisition was performed with an ECAT EXACT HR system. Wavelet-aided parametric images of non-displaceable binding potential (BP_ND ) were generated using Logan's graphical analysis with cerebellum as reference region. Correction for partial volume effects (PVE) was performed with the Müller-Gärtner method (MG). Regions of interest (ROIs) were applied to the individual parametric images and the regional BP_ND was calculated as the average parametric voxel value within each ROI. Besides comparison between subject groups, correlations between BP_ND values and scores on Mini Mental State Examination (MMSE), Disability Assessment for Dementia (DAD), and Neuropsychiatric Inventory (NPI) were expressed by Pearson correlation coefficients.

RESULTS

Mean regional BP_ND was lower in AD patients compared to control subjects and the difference was statistically significant for hippocampus, entorhinal cortex and amygdala. A statistically significant correlation was obtained between hippocampal BP_ND values and DAD scores.

CONCLUSION

The results of the present study corroborate and extend previous findings of decreased 5-HT_1A binding in AD and strengthen the support for 5-HT_1A receptor PET as a tool for assessment of neurodegenerative changes in mild AD. This article is protected by copyright. All rights reserved.

Modulating role of serotonergic signaling in sleep and memory

Serotonin is an important neurotransmitter with various receptors and wide-range effects on physiological processes and cognitive functions including sleep, learning, and memory. In this review study, we aimed to discuss the role of serotonergic receptors in modulating sleep-wake cycle, and learning and memory function. Furthermore, we mentioned to sleep deprivation, its effects on memory function, and the potential interaction with serotonin. Although there are thousands of research articles focusing on the relationship between sleep and serotonin; however, the pattern of serotonergic function in sleep deprivation is inconsistent and it seems that serotonin has not a certain role in the effects of sleep deprivation on memory function. Also, we found that the injection type of serotonergic agents (systemic or local), the doses of these drugs (dose-dependent effects), and up- or down-regulation of serotonergic receptors during training with various memory tasks are important issues that can be involved in the effects of serotonergic signaling on sleep-wake cycle, memory function, and sleep deprivation-induced memory impairments. This comprehensive review was conducted in the PubMed, Scopus, and ScienceDirect databases in June and July 2021, by searching keywords sleep, sleep deprivation, memory, and serotonin.

Neuropsychological Functioning in Users of Serotonergic Psychedelics - A Systematic Review and Meta-Analysis

Background: Serotonergic psychedelics (SPs) like LSD, psilocybin, DMT, and mescaline are a heterogeneous group of substances that share agonism at 5-HT2a receptors. Besides the ability of these substances to facilitate profoundly altered states of consciousness, persisting psychological effects have been reported after single administrations, which outlast the acute psychedelic effects. In this review and meta-analysis, we investigated if repeated SP use associates with a characteristic neuropsychological profile indicating persisting effects on neuropsychological function. Methods: We conducted a systematic review of studies investigating the neuropsychological performance in SP users, searching studies in Medline, Web of Science, embase, ClinicalTrials.gov, and EudraCT. Studies were included if they reported at least one neuropsychological measurement in users of SPs. Studies comparing SP users and non-users that reported mean scores and standard deviations were included in an exploratory meta-analysis. Results: 13 studies (N = 539) published between 1969 and 2020 were included in this systematic review. Overall, we found that only three SPs were specifically investigated: ayahuasca (6 studies, n = 343), LSD (5 studies, n = 135), and peyote (1 study, n = 61). However, heterogeneity of the methodological quality was high across studies, with matching problems representing the most important limitation. Across all SPs, no uniform pattern of neuropsychological impairment was identified. Rather, the individual SPs seemed to be associated with distinct neuropsychological profiles. For instance, one study (n = 42) found LSD users to perform worse in trials A and B of the Trail-Making task, whereas meta-analytic assessment (5 studies, n = 352) of eleven individual neuropsychological measures indicated a better performance of ayahuasca users in the Stroop incongruent task (p = 0.03) and no differences in the others (all p > 0.05). Conclusion: The majority of the included studies were not completely successful in controlling for confounders such as differences in non-psychedelic substance use between SP-users and non-users. Our analysis suggests that LSD, ayahuasca and peyote may have different neuropsychological consequences associated with their use. While LSD users showed reduced executive functioning and peyote users showed no differences across domains, there is some evidence that ayahuasca use is associated with increased executive functioning.

How do stupendous cannabinoids modulate memory processing via affecting neurotransmitter systems?

In the present study, we wanted to review the role of cannabinoids in learning and memory in animal models, with respect to their interaction effects with six principal neurotransmitters involved in learning and memory including dopamine, glutamate, GABA (γ-aminobutyric acid), serotonin, acetylcholine, and noradrenaline. Cannabinoids induce a wide-range of unpredictable effects on cognitive functions, while their mechanisms are not fully understood. Cannabinoids in different brain regions and in interaction with different neurotransmitters, show diverse responses. Previous findings have shown that cannabinoids agonists and antagonists induce various unpredictable effects such as similar effect, paradoxical effect, or dualistic effect. It should not be forgotten that brain neurotransmitter systems can also play unpredictable roles in mediating cognitive functions. Thus, we aimed to review and discuss the effect of cannabinoids in interaction with neurotransmitters on learning and memory. In addition, we mentioned to the type of interactions between cannabinoids and neurotransmitter systems. We suggested that investigating the type of interactions is a critical neuropharmacological issue that should be considered in future studies.

The Role of Tryptophan and Tyrosine in Executive Function and Reward Processing

The serotonergic precursor tryptophan and the dopaminergic precursor tyrosine have been shown to be important modulators of mood, behaviour and cognition. Specifically, research on the function of tryptophan has characterised this molecule as particularly relevant in the context of pathological disorders such as depression. Moreover, a large body of evidence has now been accumulated to suggest that tryptophan may also be involved in executive function and reward processing. Despite some clear differentiation with tryptophan, the data reviewed in this paper illustrates that tyrosine shares similar functions with tryptophan in the regulation of executive function and reward, and that these processes in turn, rather than acting in isolation, causally influence each other.

A Novel Phosphodiesterase 1 Inhibitor DSR-141562 Exhibits Efficacies in Animal Models for Positive, Negative, and Cognitive Symptoms Associated with Schizophrenia

In our drug discovery program, we identified a novel orally available and brain-penetrant phosphodiesterase (PDE) 1 inhibitor, 3-methyl-7-(tetrahydro-2H-pyran-4-yl)-2-{[trans-4-(trifluoromethyl)cyclohexyl]-methoxy}imidazo[5,1-f][1,2,4]triazin-4(3H)-one (DSR-141562). In the present study, we characterized the preclinical profile of DSR-141562. This compound has preferential selectivity for predominantly brain-expressed PDE1B over other PDE1 family members, and high selectivity for the PDE1 family over other PDE families and 65 other tested biologic targets. Oral administration of DSR-141562 at 10 mg/kg slightly elevated the cGMP concentration, and it potently enhanced the increase of cGMP induced by a dopamine D₁ receptor agonist in mouse brains. The cGMP level in monkey cerebrospinal fluid was also elevated after treatment with DSR-141562 at 30 and 100 mg/kg and could be used as a translational biomarker. Since PDE1B is believed to regulate dopaminergic and glutamatergic signal transduction, we evaluated the effects of this compound using schizophrenia-related behavioral assays. DSR-141562 at 3-30 mg/kg potently inhibited methamphetamine-induced locomotor hyperactivity in rats, while it had only minimal effects on the spontaneous locomotor activity. Furthermore, DSR-141562 at 1-100 mg/kg did not induce any signs of catalepsy in rats. DSR-141562 at 0.3-3 mg/kg reversed social interaction and novel object recognition deficits induced by repeated treatment with an N-methyl-D-aspartate receptor antagonist, phencyclidine, in mice and rats, respectively. In common marmosets, DSR-141562 at 3 and 30 mg/kg improved the performance in object retrieval with detour tasks. These results suggest that DSR-141562 is a therapeutic candidate for positive, negative, and cognitive symptoms in schizophrenia. SIGNIFICANCE STATEMENT: This is the first paper showing that a phosphodiesterase 1 inhibitor is efficacious in animal models for positive and negative symptoms associated with schizophrenia. Furthermore, we demonstrated that this compound improved cognitive function in the common marmoset, a nonhuman primate.

Co-treatment of buspirone with atypical antipsychotic drugs (AAPDs) improved neurocognitive function in chronic schizophrenia

We conducted a 24-week, randomized, double-blind parallel-controlled trial to test whether buspirone is beneficial to improve cognitive deficits of schizophrenia because it remains unclear. Two hundred patients received in random order either co-treatment buspirone with AAPDs or monotherapy with AAPDs. All patients had been treated with a stable dosage of AAPDs for at least three months. The positive and negative syndrome scale (PANSS), Hamilton Depression Scale-24 (HAMD-24), and 14-item Hamilton Rating Scale for Anxiety (HAMA-14) were used to evaluate clinical symptoms. The short version of Wechsler Adult Intelligence Scale-Revised in China (WAIS-RC) was used to assess neurocognitive function. Social function and family burden were evaluated by Social Disability Screening Schedule (SDSS) and Family Burden Interview Schedule (FBIS). All patients were enrolled at baseline and followed up after 12 and 24 weeks. A total of 196 patients completed the trial, with 99 in the combined treatment group and 97 in the control group. During the intervention, the score of PANSS, HAMD-24, and HAMA-14 decreased slightly without group differences. Repeated measures ANOVA showed significant differences between the two groups in the score of arithmetic, similarities, picture completion, block design, SDSS, and FBIS (P < 0.05), but no difference was found with regard to the score of information, digital span test, or digital symbols (P > 0.05). In conclusion, co-treatment with buspirone and APPDs outperformed APPDs alone in improving cognitive deficit and reducing family burden of schizophrenia. Buspirone may be a promising candidate for co-treatment of schizophrenia-associated cognitive deficits.

A controlled study of the efficacy and safety of tandospirone citrate combined with escitalopram in the treatment of vascular depression: A pilot randomized controlled trial at a single-center in China

Vascular depression can respond poorly to antidepressants. This study aimed to explore the efficacy and safety of tandospirone plus escitalopram for treating vascular depression with anxiety. This pilot randomized controlled trial included consecutive inpatients/outpatients with vascular depression/anxiety at the Department of Neurology, Fujian Medical University Union Hospital, China (January 2014 to December 2016). Among 157 patients screened, 100 were randomly divided into the tandospirone + escitalopram (combination therapy) and escitalopram (monotherapy) groups equally, and then followed for 8 weeks. Efficacy was evaluated using the Hamilton Depression (HAMD), Hamilton Anxiety (HAMA), Clinical Global Impression (CGI) and Mini-Mental State examination (MMSE) scales. Adverse events (AEs) were assessed with the Treatment Emergent Symptom Scale (TESS). HAMD and HAMA scores decreased progressively, showing reductions versus baseline at 1, 2, 4 and 8 weeks in both groups (P < 0.001). HAMD and HAMA scores were lower in the tandospirone + escitalopram group than those in the escitalopram group at 1 and 2 weeks (P < 0.001), but not at 4 and 8 weeks. Improvements in CGI scores (severity, improvement and efficacy indexes) were greater in the tandospirone + escitalopram group than that in the escitalopram group at 1 and 2 weeks (P < 0.01), but not at 4 and 8 weeks. The tandospirone + escitalopram group had higher MMSE scores than that in the escitalopram group at 4 and 8 weeks (P < 0.01). All AEs were mild, and the rates were comparable between groups. Augmentation of escitalopram with tandospirone accelerates the onset of anti-depressive and anxiolytic effects and improves cognitive function in patients with vascular depression and anxiety.

[Translational behavioral research using common marmosets in the psychiatric field]

The drug discovery activities for novel compounds with the superior efficacies to current drugs have been largely unsuccessful in the psychiatric field. One of the main reasons is the lack of appropriate behavioral assays and animal models for psychiatric disorders. Since the prefrontal cortex has great roles in their pathophysiology, non-human primate common marmosets with the well-developed prefrontal cortex would be useful as experimental animals in the future translational research. To measure objectively and quantitatively the psychiatric symptoms like motivational deficits, negative affective bias and cognitive impairments in patients with schizophrenia or major depressive disorder, the clinical laboratory tasks have been developed. The development of marmoset behavioral paradigms, which may correspond to the clinical laboratory tasks, have been progressed for the translational research. On the other hand, there are still limitations to develop the marmoset models resembling the pathophysiology of psychiatric disorders. We review the current state and future perspective of translational behavioral research using marmosets.

Effects of 5-HT5A receptor blockade on amnesia or forgetting

Previously the effects (0.01-3.0 mg/kg) of post-training SB-699551 (a 5-HT_5A receptor antagonist) were reported in the associative learning task of autoshaping, showing that SB-699551 (0.1 mg/kg) decreased lever-press conditioned responses (CR) during short-term (STM; 1.5-h) or (3.0 mg/kg) long-term memory (LTM; 24-h); relative to the vehicle animals. Moreover, as pro-cognitive efficacy of SB-699551 was reported in the ketamine-model of schizophrenia. Hence, firstly aiming improving performance (conditioned response, CR), in this work autoshaping lever-press vs. nose-poke response was compared; secondly, new set of animals were randomly assigned to SB-699551 plus forgetting or amnesia protocols. Results show that the nose-poke operandum reduced inter-individual variance, increased CR and produced a progressive CR until 48-h. After one week of no training/testing sessions (i.e., interruption of 216 h), the forgetting was observed; i.e., the CR% of control-saline group significantly decreased. In contrast, SB-699551 at 0.3 and 3.0 mg/kg prevents forgetting. Additionally, as previously reported the non-competitive NMDA receptor antagonist dizocilpine (0.2 mg/kg) or the non-selective cholinergic antagonist scopolamine (0.3 mg/kg) decreased CR in STM. SB-699551 (0.3 mg/kg) alone also produced amnesia-like effect. Co-administration of SB-699551-dizocilpine or SB-699551-scopolamine reversed the SB-699551 induced-amnesic effects in LTM (24-h). Nose-poke seems to be a reliable operandum. The anti-amnesic and anti-forgetting mechanisms of amnesic SB-699551-dose remain unclear. The present findings are consistent with the notion that low doses of 5-HT_5A receptor antagonists might be useful for reversing memory deficits associated to forgetting and amnesia. Of course, further experiments are necessary.

Adjunctive azapirone for schizophrenia: A meta-analysis of randomized, double-blind, placebo-controlled trials

Azapirones, which are serotonin_1A (5-HT_1A) receptor partial agonists, have been used as an adjunctive treatment for schizophrenia with mixed results. This is a meta-analysis of the efficacy and tolerability of azapirones for schizophrenia based on randomized, double-blind, placebo-controlled trials (RCTs). English and Chinese databases were systematically and independently searched by two investigators. Data were extracted and analyzed using the RevMan software (version 5.3). Seven RCTs (n = 368) of azapirones (buspirone in 6 RCTs and tandospirone in 1 RCT) were identified and analyzed. Only adjunctive buspirone outperformed placebo regarding total psychopathology [standardized mean difference: -1.03 (95% confidence interval (CI): -1.91, -0.15), P = 0.02; I² = 92%], but the significance disappeared in sensitivity analysis after removing two outlying studies, and in 10 of the 12 subgroup analyses. In 5 RCTs examining neurocognitive function of azapirones, only 2 RCTs found the superiority of buspirone in improving attention/speeded motor performance, verbal and performance intelligence. Adjunctive buspirone outperformed placebo regarding extrapyramidal symptoms [SMD:-0.51, (95%CI: -0.99, -0.02), P = 0.04; I² = 0%]. Similar rates of discontinuation [risk ratio:1.06 (95%CI:0.54, 2.07), P = 0.86, I² = 0%] and adverse drug reactions were found between both groups. Adjunctive buspirone and tandospirone failed to show efficacy for psychotic symptoms, but adjunctive buspirone may be associated with improvement in extrapyramidal symptoms and cognitive deficits in schizophrenia. Due to the preliminary nature of this meta-analysis, larger sample size and higher quality RCTs are needed to confirm these finding.

Role of tandospirone, a 5-HT1A receptor partial agonist, in the treatment of central nervous system disorders and the underlying mechanisms

5-hydroxytryptamine (5-HT, serotonin) is an important neurotransmitter in the modulation of the cognitive, behavioral and psychological functions in animals and humans. Among the fourteen subtypes of 5-HT receptor, 5-HT1A receptor has been extensively studied. Tandospirone, an azapirone derivative with strong and selective agonist effect on 5-HT1A receptor, has been used for the treatment of anxiety disorders especially generalized anxiety disorder for decades. Recently, tandospirone showed the efficacy in relieving the syndromes of social anxiety disorder and post-traumatic stress disorder as well as in potentiating the effect of antidepressants in the treatment of depression in both preclinical and clinical studies. More impressively, the beneficial effect of tandospirone has been revealed on improvement of motor dysfunction of Parkinson's disease and cognitive deficits of schizophrenia either in monotherapy or in combination with other drugs. This review discusses the superiority of tandospirone in the treatment of the disorders and associated mechanisms in central nervous system from the literature.

Frameworking memory and serotonergic markers

The evidence for neural markers and memory is continuously being revised, and as evidence continues to accumulate, herein, we frame earlier and new evidence. Hence, in this work, the aim is to provide an appropriate conceptual framework of serotonergic markers associated with neural activity and memory. Serotonin (5-hydroxytryptamine [5-HT]) has multiple pharmacological tools, well-characterized downstream signaling in mammals’ species, and established 5-HT neural markers showing new insights about memory functions and dysfunctions, including receptors (5-HT1A/1B/1D, 5-HT2A/2B/2C, and 5-HT3-7), transporter (serotonin transporter [SERT]) and volume transmission present in brain areas involved in memory. Bidirectional influence occurs between 5-HT markers and memory/amnesia. A growing number of researchers report that memory, amnesia, or forgetting modifies neural markers. Diverse approaches support the translatability of using neural markers and cerebral functions/dysfunctions, including memory formation and amnesia. At least, 5-HT1A, 5-HT4, 5-HT6, and 5-HT7receptors and SERT seem to be useful neural markers and therapeutic targets. Hence, several mechanisms cooperate to achieve synaptic plasticity or memory, including changes in the expression of neurotransmitter receptors and transporters.

The atypical antipsychotic blonanserin reverses (+)-PD-128907- and ketamine-induced deficit in executive function in common marmosets

Antagonism of the dopamine D3 receptor is considered a promising strategy for the treatment of cognitive impairment associated with schizophrenia. We have previously reported that the atypical antipsychotic blonanserin, a dopamine D2/D3 and serotonin 5-HT2A receptor antagonist, highly occupies dopamine D3 receptors at its antipsychotic dose range in rats. In the present study, we evaluated the effects of blonanserin on executive function in common marmosets using the object retrieval with detour (ORD) task. The dopamine D3 receptor-preferring agonist (+)-PD-128907 at 1mg/kg decreased success rate in the difficult trial, but not in the easy trial. Since the difference between the two trials is only cognitive demand, our findings indicate that excess activation of dopamine D3 receptors impairs executive function in common marmosets. Blonanserin at 0.1mg/kg reversed the decrease in success rate induced by (+)-PD-128907 in the difficult trial. This finding indicates that blonanserin has beneficial effect on executive function deficit induced by activation of the dopamine D3 receptor in common marmosets. Next, and based on the glutamatergic hypothesis of schizophrenia, the common marmosets were treated with the N-methyl-d-aspartate (NMDA) receptor antagonist ketamine. Ketamine at sub-anesthetic doses decreased success rate in the difficult trial, but not in the easy trial. Blonanserin at 0.1mg/kg reversed the decrease in success rate induced by ketamine in the difficult trial. The findings of this study suggest that blonanserin might have beneficial effect on executive dysfunction in patients with schizophrenia.

Serotonin, neural markers, and memory

Diverse neuropsychiatric disorders present dysfunctional memory and no effective treatment exits for them; likely as result of the absence of neural markers associated to memory. Neurotransmitter systems and signaling pathways have been implicated in memory and dysfunctional memory; however, their role is poorly understood. Hence, neural markers and cerebral functions and dysfunctions are revised. To our knowledge no previous systematic works have been published addressing these issues. The interactions among behavioral tasks, control groups and molecular changes and/or pharmacological effects are mentioned. Neurotransmitter receptors and signaling pathways, during normal and abnormally functioning memory with an emphasis on the behavioral aspects of memory are revised. With focus on serotonin, since as it is a well characterized neurotransmitter, with multiple pharmacological tools, and well characterized downstream signaling in mammals' species. 5-HT_1A, 5-HT₄, 5-HT₅, 5-HT₆, and 5-HT₇ receptors as well as SERT (serotonin transporter) seem to be useful neural markers and/or therapeutic targets. Certainly, if the mentioned evidence is replicated, then the translatability from preclinical and clinical studies to neural changes might be confirmed. Hypothesis and theories might provide appropriate limits and perspectives of evidence.