Testing the NASA BioSentinel Pixel Dosimeter Using Gamma-ray and Neutron Sources at the LLNL Calibration Lab.

ABSTRACT: The objective of this paper is to evaluate the accuracy of the NASA BioSentinel Pixel Dosimeter (BPD) using gamma-ray and neutron sources in a standard calibration lab. The dosimeter tested here is the ground-based version of the BPD that will be onboard the BioSentinel mission. The BPD was exposed to radiation from 60Co, 137Cs, and 252Cf at selected distances (dose rates) at the Lawrence Livermore National Laboratory (LLNL) Radiation Calibration Laboratory (RCL), and the results were compared with NIST traceable benchmark values. It is recognized that these sources are not analogs for the space environment but do provide direct comparisons between BPD response and well characterized calibration lab values. For gamma rays, the BPD measured absorbed dose agrees to ≤ 3.8% compared with RCL benchmark values. For neutrons, the results show that the BPD is insensitive, i.e., the BPD detected only the gamma-ray dose component from 252Cf. The LET spectra obtained for gamma rays from 60Co and 252Cf are consistent with expectations for these gamma-ray energies, but the LET spectrum from the 137Cs gamma rays differs substantially. The potential causes for this difference are the high dose rate from 137Cs and the lower secondary electron energy produced by 137Cs gamma rays. However, neither of these results in errors in the absorbed dose. Based on comparisons with NIST-traceable standards, it is evident that the BPD can measure absorbed dose accurately from low LET charged particles. The sensor's insensitivity to neutrons is unlikely to be a limitation for the BioSentinel mission due to the expected low secondary neutron fluence.

Dynamics of Mixed- Candida Species Biofilms in Response to Antifungals.

Oral infections caused by Candida species, the most commonly isolated human fungal pathogen, are frequently associated with biofilms. Although Candida albicans is the predominant organism found in patients with oral thrush, a biofilm infection, there is an increasing incidence of oral colonization and infections caused by non- albicans Candida species, including C. glabrata, C. dubliniensis, and C. tropicalis, which are frequently more resistant to antifungal treatment. While single-species Candida biofilms have been well studied, considerably less is known about the dynamics of mixed- Candida species biofilms and how these dynamics are altered by antifungal treatment. To address these questions, we developed a quantitative polymerase chain reaction-based approach to determine the precise species composition of mixed- Candida species biofilms formed by clinical isolates and laboratory strains in the presence and absence of clinically relevant concentrations of 3 commonly used antifungals: fluconazole, caspofungin, and amphotericin B. In monospecies biofilms, fluconazole exposure favored growth of C. glabrata and C. tropicalis, while caspofungin generally favored significant growth of all species to a varying degree. Fluconazole was not effective against preformed mixed- Candida species biofilms while amphotericin B was potent. As a general trend, in mixed- Candida species biofilms, C. albicans lost dominance in the presence of antifungals. Interestingly, presence in mixed versus monospecies biofilms reduced susceptibility to amphotericin B for C. tropicalis and C. glabrata. Overall, our data suggest that antifungal treatment favors the growth of specific non- albicans Candida species in mixed- Candida species biofilms.

Multi-state outcome analysis of treatments (MOAT): application of a new approach to evaluate outcomes in longitudinal studies of bipolar disorder.

Survival analyzes are usually based on a single point in time predefined event. Dissatisfied with this approach to evaluating maintenance treatment outcomes, we developed the Multi-state Outcome Analysis of Treatments (MOAT) methodology using a combined database from two FDA registration studies of lamotrigine, lithium and placebo. MOAT partitions total survival time into clinically distinct periods operationally defined by cutpoints on rating scales. For bipolar disorder (BD), the clinical states are remission, subsyndromal and syndromal mania, mixed states or depression. MOAT results can be crossed with information about tolerability and functioning to yield an outcome system integrating efficacy and tolerability. As found in the original analysis, both drugs were associated with longer time in study compared with the placebo. MOAT supplements this by finding that both drugs increased the time remitted compared with placebo. However, a substantial amount of time in all three treatments was spent in subsyndromal depression. Time with manic symptoms was reduced with lithium, but not lamotrigine. Patients on placebo neither benefitted nor had adverse effects from the assignment but experienced more syndromal levels of symptoms and were terminated from the study sooner than either drug treated group. Lithium was associated with both benefit in time manic and worse tolerability compared with placebo. In summary, lamotrigine was associated with limited therapeutic benefit but not harm; lithium with both benefit and harm; and placebo with neither. MOAT describes not only quantity but also quality of time spent in longitudinal studies, providing a more clinically informative picture than Kaplan-Meier survival analysis.

Measurement of the T + T neutron spectrum using the national ignition facility.

Neutron time-of-flight spectra from inertial confinement fusion experiments with tritium-filled targets have been measured at the National Ignition Facility. These spectra represent a significant improvement in energy resolution and statistics over previous measurements, and afford the first definitive observation of a peak resulting from sequential decay through the ground state of (5)He at low reaction energies E(c.m.) 100

Lamotrigine vs. lamotrigine plus divalproex in randomized, placebo-controlled maintenance treatment for bipolar depression.

OBJECTIVE: To compare the maintenance efficacy of lamotrigine (Lam) to combination therapy of Lam+divalproex ER (Div) in recently depressed patients with bipolar disorder (BD). METHOD: We randomized 86 BD I or II patients in a major depressive episode to 8 months of double-blind treatment with Lam+placebo or Lam+Div. To be eligible for randomization, patients had to achieve control of both depressive and manic symptoms during an open phase that included both Lam and Div. RESULTS: Time to depressive episode did not differ significantly by Kaplan-Maier survival analysis (χ2=1.82, df=1, P=0.18). However, several secondary outcomes did show significant differences. The proportion of Lam+placebo patients who had at least one Montgomery-Asberg Depression Rating Scale (MADRS) score≥15 during the maintenance phase was 67% (30/45) compared with 44% (18/41) for the Lam+Div group (χ2=4.51, P=0.03). Among BD I patients assigned to Lam+placebo, 71.4% (25/35) had at least one visit with MADRS score≥15 compared with 36.7% (11/30) among Lam+Div patients (χ2=7.89, df=1, P=0.005). CONCLUSION: Lam+Div generally provided greater maintenance efficacy than Lam alone for depressive indices in recently depressed BD patients.

Absence of evidence for bornavirus infection in schizophrenia, bipolar disorder and major depressive disorder.

In 1983, reports of antibodies in subjects with major depressive disorder (MDD) to an as-yet uncharacterized infectious agent associated with meningoencephalitis in horses and sheep led to molecular cloning of the genome of a novel, negative-stranded neurotropic virus, Borna disease virus (BDV). This advance has enabled the development of new diagnostic assays, including in situ hybridization, PCR and serology based on recombinant proteins. Since these assays were first implemented in 1990, more than 80 studies have reported an association between BDV and a wide range of human illnesses that include MDD, bipolar disorder (BD), schizophrenia (SZ), anxiety disorder, chronic fatigue syndrome, multiple sclerosis, amyotrophic lateral sclerosis, dementia and glioblastoma multiforme. However, to date there has been no blinded case-control study of the epidemiology of BDV infection. Here, in a United States-based, multi-center, yoked case-control study with standardized methods for clinical assessment and blinded serological and molecular analysis, we report the absence of association of psychiatric illness with antibodies to BDV or with BDV nucleic acids in serially collected serum and white blood cell samples from 396 subjects, a study population comprised of 198 matched pairs of patients and healthy controls (52 SZ/control pairs, 66 BD/control pairs and 80 MDD/control pairs). Our results argue strongly against a role for BDV in the pathogenesis of these psychiatric disorders.

Academic-community partnership: an orientation for employees of a community mental health agency to its research program.

CONTEXT: Community agency employees' interest and involvement in academic-community research partnerships are keys to successful collaborations. One main barrier to success can be employees' lack of knowledge about research. We present data on an "orientation to research" program for community agency employees in a large U.S. city designed to improve knowledge about research in general and that specific to the agency. METHODS: We developed an agency intranet website, a scavenger hunt to facilitate learning through the intranet research website, and a ten-item quantitative knowledge assessment tool. Academic and agency partners were actively involved in the design of the program and its evaluation. FINDINGS: More educated and long-term employees had higher pre-test scores but not post-test scores. Significant improvement in post-test scores was observed for employees after completion of the program. Informal feedback about course content and the academic-community partnership was positive. CONCLUSIONS: This report examines the feasibility of a structured knowledge program targeted at community agency employees at all levels within an agency. We believe that this approach is generalizable to other settings to the extent that there are shared interests, resources, and investment of the academic partner and agency.

The global network on dental education: a new vision for IFDEA.

The advent of globalization has changed our perspectives radically. It presents increased understanding of world affairs, new challenges and exciting opportunities. The inequitable distribution and use of finite energy resources and global warming are just two examples of challenges that can only be addressed by concerted international collaboration. Globalization has become an increasingly important influence on dentistry and dental education. The International Federation for Dental Educators and Associations (IFDEA) welcomes the challenges it now faces as a player in a complex multifaceted global community. This report addresses the new circumstances in which IFDEA must operate, taking account of the recommendations made by other working groups. The report reviews the background and evolution of IFDEA and describes the extensive developments that have taken place in IFDEA over the past year with the introductions of a new Constitution and Bylaws overseen by a newly established Board of Directors. These were the consequence of a new mission, goals and objectives for IFDEA. An expanded organization is planned using http://www.IFDEA.org as the primary instrument to facilitate the exchange of knowledge, programmes and expertise between colleagues and federated associations throughout the world, thereby promoting higher standards in oral health through education in low-, middle- and high-income countries of the world. Such aspirations are modified by the reality and enormity of poverty-related global ill health.

Tranylcypromine vs. lamotrigine in the treatment of refractory bipolar depression: a failed but clinically useful study.

OBJECTIVE: To compare the efficacy and tolerability of tranylcypromine vs. lamotrigine in bipolar depression not responding to conventional antidepressants. METHOD: Bipolar depressed patients received open randomized treatment with tranylcypromine or lamotrigine as add-on to a mood stabilizer during 10 weeks. In a second treatment phase, non-responding patients could receive the opposite drug. Outcome criteria were response (measured with CGI-BP and IDS-C), switch into mania, and completion of the study. RESULTS: Only 20 of 70 planned patients were randomized, due to problems with recruitment, and 19 patients received any medication. During the first treatment phase 5/8 patients (62.5%) responded to tranylcypromine without switch into mania, compared with 4/11 patients (36.4%) on lamotrigine with two switches (statistically not significant). Over both treatment phases, 8/10 patients (80%) receiving tranylcypromine completed the study vs. 5/13 (38.5%) on lamotrigine (likelihood 0.02). CONCLUSION: There still appears to be a role for tranylcypromine in the treatment of refractory bipolar depression. Larger controlled studies are demanded.

Mood switch in bipolar depression: comparison of adjunctive venlafaxine, bupropion and sertraline.

BACKGROUND: Few studies have examined the relative risks of switching into hypomania or mania associated with second-generation antidepressant drugs in bipolar depression. AIMS: To examine the relative acute effects of bupropion, sertraline and venlafaxine as adjuncts to mood stabilisers. METHOD: In a 10-week trial, participants receiving out-patient treatment for bipolar disorder (stratified for rapid cycling) were randomly treated with a flexible dose of one of the antidepressants, or their respective matching placebos, as adjuncts to mood stabilisers. RESULTS: A total of 174 adults with bipolar disorder I, II or not otherwise specified, currently in the depressed phase, were included. All three antidepressants were associated with a similar range of acute response (49-53%) and remission (34-41%). There was a significantly increased risk of switches into hypomania or mania in participants treated with venlafaxine compared with bupropion or sertraline. CONCLUSIONS: More caution appears indicated in the use of venlafaxine rather than bupropion or sertraline in the adjunctive treatment of bipolar depression, especially if there is a prior history of rapid cycling.

Antidepressants and suicidal behaviour in unipolar depression.

OBJECTIVE: To compare the rates of suicidal behaviour during vs. after discontinuation of treatment with antidepressants, and to determine the comparative rates of suicidal behaviour for patients maintained on tricyclic (TCA) vs. selective serotonin reuptake inhibitor (SSRI) antidepressants. METHOD: Charts were reviewed for 521 patients with major depressive disorder and/or dysthymic disorder. Periods of active treatment or discontinuation with SSRIs or TCAs were determined. Rates of completed suicide, suicide attempts, and hospitalization for suicidality were analyzed. RESULTS: There was greater than a five-fold increase in risk for suicidal behaviour after discontinuation of antidepressant treatment (P < 0.0001). The rates of suicidal behavior during treatment with SSRIs or TCAs were similar. CONCLUSION: Suicidal behaviour in unipolar depressed patients treated with antidepressants increases substantially after medication discontinuation. This effect occurred in both patients who were maintained on SSRIs and TCAs. The findings support a possible protective effect on suicidal behaviour for both SSRIs and TCAs.

The impact of depression and fluoxetine treatment on obstetrical outcome.

INTRODUCTION: This study prospectively followed women over the course of pregnancy to assess the impact of depression and/or antidepressant treatment on obstetrical outcome. METHOD: Sixty-four outpatient women with an Axis I diagnosis of major depressive disorder or no psychiatric history were followed in each trimester of pregnancy with administration of the CES-D. A subset of the women with depression received treatment with fluoxetine during pregnancy. Subjects with a CES-D score greater than 16 at any time point were further assessed for the presence of an active major or minor depressive episode. Primary outcome variables included infant gestational age, birth weight, Apgar score, and admission to the neonatal intensive care unit. RESULTS: Analyzable data were available for 62 women. No significant differences were found in outcome variables between those women with exposure to medication and/or prenatal depressed mood and those women without a history of depression. CONCLUSIONS: In contrast to other studies, our study did not demonstrate an adverse effect of fluoxetine exposure per se on obstetrical outcome. In addition, we did not find a significant impact of depression during pregnancy on obstetrical outcome.

Forward and backward visual masking in schizophrenia: influence of age.

BACKGROUND: Visual masking tasks assess the earliest stages of visual processing. This study was conducted to address: (1) whether schizophrenia patients show masking deficits after controlling for sensory input factors; (2) whether patients have relatively intact forward masking (when the mask precedes the target) compared with backward masking (when the mask follows the target); and (3) whether the masking deficits in schizophrenia reflect an accelerated age-related decline in performance. METHOD: A staircase method was used to ensure that the unmasked target identification was equivalent across subjects to eliminate any confounding due to differences in discrimination of simple perceptual inputs. Three computerized visual masking tasks were administered to 120 schizophrenia patients (ages 18-56) and 55 normal comparison subjects (ages 19-54) under both forward and backward masking conditions. The tasks included: (1) locating a target; (2) identifying a target with a high-energy mask; and (3) identifying a target with a low-energy mask. RESULTS: Patients showed deficits across all three masking tasks. Interactions of group by forward versus backward masking were not significant, suggesting that deficits in forward and backward masking were comparable. All three conditions showed an age-related decline in performance and rates of decline were comparable between patients and controls. Two of the masking conditions showed increased rates of decline in backward, compared to forward, masking. CONCLUSIONS: We found age-related decline in performance that was comparable for the two groups. In addition, we failed to find evidence of a relative sparing of forward masking in schizophrenia. These results suggest that: (1) early visual processing deficits in schizophrenia are not due to a simple perceptual input problem; (2) sustained channels are involved in the masking deficit (in addition to transient channels); and (3) for the age range in this study, these deficits in schizophrenia are not age-related.

Does 'errorless learning' compensate for neurocognitive impairments in the work rehabilitation of persons with schizophrenia?

BACKGROUND: Because neurocognitive impairments of schizophrenia appear to be 'rate limiting' in the acquisition of skills for community functioning, it is important to develop efficacious rehabilitative interventions that can compensate for these impairments. Procedures based on errorless learning may facilitate work rehabilitation because they effectively automate training of work and other skills, thereby reducing the cognitive burden on persons with schizophrenia. METHOD: The present study examined the ability of a training method based on errorless learning to compensate for neurocognitive deficits in teaching two entry-level job tasks (index card filing and toilet-tank assembly) to a sample of 54 unemployed, clinically stable schizophrenic and schizoaffective disorder out-patients. Participants were randomly assigned to one of two training groups, errorless learning v. conventional trial-and-error type instruction. Prior to randomization, all subjects were administered a neurocognitive battery. Job task performance was assessed by percentage accuracy scores immediately after training. RESULTS: For three of the six inter-relationships among neurocognitive functioning and training condition, the pattern was the same: the errorless learning group scored high in job task performance regardless of neurocognitive impairment, whereas the conventional instruction group showed a close correspondence between job task performance and degree of neurocognitive impairment. CONCLUSIONS: These findings support errorless learning as a technique that can compensate for neurocognitive deficits as they relate to the acquisition of new skills and abilities in the work rehabilitation of persons with schizophrenia.

Fluphenazine plasma level monitoring for patients receiving fluphenazine decanoate.

BACKGROUND: Finding a dose of an antipsychotic for maintenance therapy that is both safe and effective can be difficult because clinicians are unable to titrate dose against clinical response in patients who are already stable. Therapeutic monitoring of antipsychotic plasma levels has the potential for helping clinicians in dosage selection. With this in mind, we evaluated the usefulness of monitoring fluphenazine plasma levels for patients with schizophrenia who were receiving maintenance treatment with fluphenazine decanoate. METHOD: Thirty-one patients with schizophrenia were randomly assigned to low, medium, or high (0.1-0.3, 0.3-0.6, 0.6-1.0 ng/ml) plasma levels of fluphenazine. The dose of fluphenazine decanoate was adjusted in order to maintain patients in their assigned range. Side effects, psychopathology, and psychotic exacerbations were measured during the year following randomization. RESULTS: All of the psychotic exacerbations occurred during the first eight weeks following randomization, before patients had adequate time to reach their plasma level assignments. We did not find a relationship between plasma levels of fluphenazine and clinical outcomes or side effects. CONCLUSION: Our results do not provide support for the usefulness of monitoring fluphenazine plasma levels for patients receiving fluphenazine decanoate.

Clinical outcome following neuroleptic discontinuation in patients with remitted recent-onset schizophrenia.

OBJECTIVE: The goal of this report was to examine the clinical course following neuroleptic discontinuation of patients with recent-onset schizophrenia who had been receiving maintenance antipsychotic treatment for at least 1 year. METHOD: Fifty-three volunteer patients with recent-onset schizophrenia who had been clinically stabilized on a maintenance regimen of fluphenazine decanoate for a mean of 16.7 months had their antipsychotic medications withdrawn under clinical supervision. Participants initially entered a 24-week, double-blind crossover trial in which fluphenazine and placebo were administered for 12 weeks each. For those who did not experience symptom exacerbation or relapse during this period, fluphenazine was openly withdrawn; participants were then followed for up to 18 additional months. RESULTS: When a low threshold for defining symptom reemergence was used, 78% (N=39 of 50) of the patients experienced an exacerbation or relapse within 1 year; 96% (N=48 of 50) did so within 2 years. Mean time to exacerbation or relapse was 235 days. When hospitalization was used as a relapse criterion, only six of 45 of individuals (13%) experiencing an exacerbation or relapse who continued in treatment in the clinic were hospitalized, demonstrating the sensitivity of the psychotic exacerbation criterion. CONCLUSIONS: The vast majority of clinically stable individuals with recent-onset schizophrenia will experience an exacerbation or relapse after antipsychotic discontinuation, even after more than a year of maintenance medication. However, clinical monitoring and a low threshold for reinstating medications can prevent hospitalization for the majority of these patients.

Fluoxetine and norfluoxetine concentrations in nursing infants and breast milk.

BACKGROUND: This study's goal was to characterize nursing infants' exposure to fluoxetine through breast milk and to identify variables for minimizing such exposure. METHODS: Nursing women on stable daily doses of fluoxetine were recruited into the study. Breast milk, maternal and infant serum concentrations of fluoxetine and norfluoxetine were determined with high-performance liquid chromatography. RESULTS: Nineteen nursing women one with a pair of dizygotic twins participated in the study. The women were on stable daily doses of fluoxetine (10-60 mg/day) and all but two took the medication during the last trimester of pregnancy. Fluoxetine was detectable in 30% (n = 6) of the nursing infant sera (< 1-84 ng/mL), whereas norfluoxetine was found in 85% (N = 17) (< 1-265 ng/mL). Peak breast milk concentrations occurred approximately 8 hours after maternal dosing and predicted norfluoxetine concentrations in infant serum. Maternal serum fluoxetine and norfluoxetine concentrations correlated highly with infant norfluoxetine concentrations. A daily maternal fluoxetine dosage of 20 mg or lower was significantly less likely to produce detectable concentrations of either fluoxetine or norfluoxetine in infants compared to higher daily dosages. No adverse effects were reported in any infant. CONCLUSIONS: Our findings demonstrate that maternal serum and peak breast milk concentrations of fluoxetine and norfluoxetine predict nursing infant serum norfluoxetine concentrations. In nursing women taking 20 mg/day or less of fluoxetine, infant serum concentrations were typically low.

Does thyroid supplementation accelerate tricyclic antidepressant response? A review and meta-analysis of the literature.

OBJECTIVE: The delayed onset of therapeutic response to antidepressants remains a major problem in the treatment of depression. Among the strategies to accelerate response to treatment, the early addition of thyroid hormone to antidepressants has been suggested as a viable method. The authors performed a meta-analysis of the literature on the use of thyroid hormone supplementation to accelerate the treatment of depression to determine whether there is sufficient evidence to support the clinical efficacy of this strategy. METHOD: Both a computer-aided search of the National Library of Medicine MEDLINE and an intensive search by hand were conducted to identify all double-blind, placebo-controlled studies assessing the concomitant administration of thyroid hormone and antidepressant to accelerate clinical response in patients with nonrefractory depression. RESULTS: Six studies were identified. All were conducted with triiodothyronine (T(3)) and a tricyclic antidepressant. Five of the six studies found T(3) to be significantly more effective than placebo in accelerating clinical response. The pooled, weighted effect size index was 0.58, and the average effect was highly significant. Further, the effects of T(3) acceleration were greater as the percentage of women participating in the study increased. CONCLUSIONS: This meta-analysis supports the efficacy of T(3) in accelerating clinical response to tricyclic antidepressants in patients with nonrefractory depression. Furthermore, women may be more likely than men to benefit from this intervention.

The impact of antidepressant discontinuation versus antidepressant continuation on 1-year risk for relapse of bipolar depression: a retrospective chart review.

BACKGROUND: Current treatment guidelines recommend discontinuation of an antidepressant within 3 to 6 months after remission of depression in patients with bipolar illness. Yet few studies directly compare the impact of antidepressant discontinuation versus antidepressant continuation on the risk for depressive relapse in patients with bipolar disorder who have been successfully treated for a depressive episode. METHOD: In a retrospective chart review, patients with DSM-IV bipolar disorder who were treated for an index episode of depression by adding antidepressant medication to ongoing mood stabilizer medications were identified. The risk of depressive relapse in 25 subjects who stopped antidepressant medications after improvement was compared with the risk of depressive relapse in 19 subjects who continued antidepressants after improvement. RESULTS: Termination of antidepressant medication significantly increased the risk of a depressive relapse. Antidepressant continuation was not significantly associated with an increased risk of mania. CONCLUSION: While this study may have been limited by the retrospective nature of the chart review, nonrandomized assignment of treatment, and reliance on unstructured progress notes, it suggests that antidepressant discontinuation may increase the risk of depressive relapse in some patients with bipolar disorder. Further research is needed to clarify whether maintenance antidepressant treatment may be warranted in some patients with bipolar disorder, especially in those with frequent recurrent depressive episodes.

Age-related changes in frontal and temporal lobe volumes in men: a magnetic resonance imaging study.

BACKGROUND: Imaging and postmortem studies provide converging evidence that, beginning in adolescence, gray matter volume declines linearly until old age, while cerebrospinal fluid volumes are stable in adulthood (age 20-50 years). Given the fixed volume of the cranium in adulthood, it is surprising that most studies observe no white matter volume expansion after approximately age 20 years. We examined the effects of the aging process on the frontal and temporal lobes. METHODS: Seventy healthy adult men aged 19 to 76 years underwent magnetic resonance imaging. Coronal images focused on the frontal and temporal lobes were acquired using pulse sequences that maximized gray vs white matter contrast. The volumes of total frontal and temporal lobes as well as the gray and white matter subcomponents were evaluated. RESULTS: Age-related linear loss in gray matter volume in both frontal (r = -0.62, P<.001) and temporal (r = -0.48, P<.001) lobes was confirmed. However, the quadratic function best represented the relationship between age and white matter volume in the frontal (P<.001) and temporal (P<.001) lobes. Secondary analyses indicated that white matter volume increased until age 44 years for the frontal lobes and age 47 years for the temporal lobes and then declined. CONCLUSIONS: The changes in white matter suggest that the adult brain is in a constant state of change roughly defined as periods of maturation continuing into the fifth decade of life followed by degeneration. Pathological states that interfere with such maturational processes could result in neurodevelopmental arrests in adulthood.