Serotonin (5-HT) plays a key role in early brain development, and manipulation of 5-HT levels during this period can have lasting neurobiological and behavioral consequences. It is unclear how perinatal exposure to drugs, such as selective serotonin reuptake inhibitors (SSRIs), impacts cortical neural network function and what mechanism(s) may elicit the disruption of normal neuronal connections/interactions. In this article, we report on cortical wiring organization after pre-and postnatal exposure to the SSRI citalopram. We show that manipulation of 5-HT during early development in both in vitro and in vivo models disturbs characteristic chemoarchitectural and electrophysiological brain features, including changes in raphe and callosal connections, sensory processing, and myelin sheath formation. Also, drug-exposed rat pups exhibit neophobia and disrupted juvenile play behavior. These findings indicate that 5-HT homeostasis is required for proper brain maturation and that fetal/infant exposure to SSRIs should be examined in humans, particularly those with developmental dysfunction, such as autism.S erotonin (5-HT) has long been postulated to play a trophic role in brain morphogenesis, including cell proliferation, migration, and differentiation. It is also known to be one of the first neurotransmitters to appear in the central nervous system (1, 2). An obvious question that can be raised relates to whether perinatal exposure to antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), can affect cortical circuit development and function. Perhaps one of the most intriguing previous findings related to 5-HT and early cortical organization was the observation from immunohistochemical and 5-HT transporter (SERT) binding studies that, at postnatal days 2-14 (P2-P14), rodent primary sensory cortex (notably layer IV of visual, auditory, and somatosensory areas) is transiently innervated by aggregates of fine grainlooking 5-HT-containing processes (3)(4)(5). Surprisingly, it became clear that, in early brain development, 5-HT is taken up into glutamatergic thalamocortical terminals (6, 7) and used in combination with the 5-HT 1B receptor on layer IV afferents (8). At present, the functional implication of such transient 5-HT expression and targeting, namely the primary sensory thalamocortical afferents during early development, remains unknown.5-HT and Abnormal Brain Development. Interestingly, manipulations of rodent brain 5-HT levels during early development, either through increases (produced in SERT or monoamine oxidase knockout mice) or decreases (produced by parachlorophenylalanine or other treatments), have been shown to produce the downstream effect of interfering with the formation of the whisker (barrel) representation in the primary somatosensory cortex and promoting aggressive and/or anxiety-related behaviors (9-14). Furthermore, early-life modification of 5-HT levels has been shown to cause overreaction to auditory or tactile sensory stimulation (15) and abnormal response properties of cor...

Idiopathic normal pressure hydrocephalus (NPH) remains both oversuspected on clinical grounds and underconfirmed when based on immediate and sustained response to cerebrospinal fluid diversion. Poor long-term postshunt benefits and findings of neurodegenerative pathology in most patients with adequate follow-up suggest that hydrocephalic disorders appearing in late adulthood may often result from initially unapparent parenchymal abnormalities. We critically review the NPH literature, highlighting the near universal lack of blinding and controls, absence of specific clinical, imaging, or pathological features, and ongoing dependence for diagnostic confirmation on variable cutoffs of gait response to bedside fluid-drainage testing. We also summarize our long-term institutional experience, in which postshunt benefits in patients with initial diagnosis of idiopathic NPH persist in only 32% of patients at 36 months, with known revised diagnosis in over 25% (Alzheimer's disease, dementia with Lewy bodies, and progressive supranuclear palsy). We postulate that previously reported NPH cases with "dual" pathology (ie, developing a "second" disorder) more likely represent ventriculomegalic presentations of selected neurodegenerative disorders in which benefits from shunting may be short-lived, with a consequently unfavorable risk-benefit ratio. Ann Neurol 2017;82:503-513.

We have demonstrated that neonatal exposure to selective serotonin reuptake inhibitors has lasting effects on behavior and serotonergic neurons in Long Evans rats. Hyperserotoninemia and altered sensory processing are reported in autistic spectrum disorders (ASD). We hypothesized that early life exposure to SSRIs alters sensory processing, disrupts responses to novelty and impairs social interactions in a manner similar to that observed in ASD. Male and female Long-Evans rat pups were administered citalopram, buproprion, fluoxetine, or saline from postnatal day (P) 8 to 21. Rats were tested for response to a novel tone before weaning (P25). Later, rats were tested 2× for response to a novel object (P39), and to a novel conspecific (P78, P101). In addition, rats were assessed for juvenile play behaviors (P32–P34) and later, we assessed sexual response to an estrus female in male rats (P153–184). Antidepressant exposure increased freezing after tone, diminished novel object exploration and reduced conspecific interaction up to 3× compared to saline exposed rats. Juvenile play was profoundly reduced in antidepressant-exposed males when compared to saline exposed groups. Exposure to the SSRIs, but not bupropion disrupted male sexual behaviors. Moreover, specific male responses to female proceptive behaviors were disrupted in SSRI, but not bupropion exposed rats. We conclude that neonatal exposure to antidepressants in rats results in sensory and social abnormalities that parallel many of those reported in ASD.

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ObjectiveReview the effect of orthostatic hypotension (OH) and rapid-eye-movement sleep behavioural disorder (RBD) on survival, cognitive impairment and postural stability, and discuss pathogenic mechanisms involved in the association of these two common non-motor features with relevant clinical outcomes in α-synucleinopathies.MethodsWe searched PubMed (January 2007–February 2019) for human studies of OH and RBD evaluating cognitive impairment, postural instability, and survival in Parkinson’s disease (PD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA) and pure autonomic failure (PAF). Included studies were analysed for design, key results and limitations as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.ResultsOH and RBD showed a positive association with cognitive impairment in PD and DLB, conflicting association in PAF, and no association in MSA. OH was correlated with incident falls and postural instability in PD and DLB but not in MSA. The association between RBD and postural instability was inconclusive; positive in five studies, negative in seven. OH, but not RBD, correlated with reduced survival in PD, DLB and MSA. The combination of OH and RBD was associated with cognitive impairment and more rapid progression of postural instability.ConclusionsOH and RBD yielded individual and combined negative effects on disability in α-synucleinopathies, reflecting a ‘malignant’ phenotype of PD with early cognitive impairment and postural instability. Underlying mechanisms may include involvement of selected brainstem cholinergic and noradrenergic nuclei.