Cholinergic enhancement of episodic memory in healthy young adults

Functional connectivity and cognitive changes after donepezil treatment in healthy participants

RATIONALE

Donepezil is a potent, noncompetitive, reversible, clinically effective acetylcholinesterase inhibitor. The effects of this drug on healthy brains have seldom been investigated.

OBJECTIVES

The primary objective of the present study was to identify possible functional connectivity markers of the effect of donepezil in healthy young adult volunteers.

METHODS

The study had a double-blind, randomized, crossover design. 30 healthy adult volunteers underwent resting-state MRI scans during 15 days of donepezil or placebo treatment, in accordance with the design.

RESULTS

Results showed significant differences in intrinsic functional connectivity between donepezil and placebo, mainly in the right executive control network (RECN). More specifically, we found a decrease in the connectivity of the right inferior parietal node with other RECN nodes. Analysis using the cingulate cortex and parahippocampal regions as seeds also revealed complex modulation of functional connectivity in the donepezil condition.

CONCLUSIONS

In conclusion, donepezil treatment for 15 days may result in reorganization of resting-state networks, compared with placebo.

Neuroenhancement: State of the Art and Future Perspectives

Pharmacological neuroenhancement refers to the non-medical use of prescription drugs, alcohol, illegal drugs, or the so-called soft enhancers for the purpose of improving cognition, mood, pro-social behavior, or work and academic performance. This phenomenon is undoubtedly more frequent than previously supposed especially amongst university students. The aim of the present paper was to carefully review and comment on the available literature on neuroenhancement, according to Prisma guidelines. The results showed a great use of all prescribed drugs (benzodiazepines, antidepressants, antipsychotics, nootropic compounds, and especially stimulants) as neuroenhancers amongst healthy subjects, although probably the real prevalence is underestimated. The use of illicit drugs and soft enhancers is similarly quite common. Data on the improvement of cognition by other compounds, such as oxytocin and pheromones, or non-pharmacological techniques, specifically deep brain stimulation and transcranial magnetic stimulation, are still limited. In any case, if it is true that human beings are embedded by the desire to overcome the limits of their intrinsic nature, neuroenhancement practices put into question the concept of authenticity. Therefore, the problem appears quite complex and requires to be deepened and analyzed with no prejudice, although within an ethical conceptual frame.

Nootropic drugs: Methylphenidate, modafinil and piracetam - Population use trends, occurrence in the environment, ecotoxicity and removal methods - A review

Pharmaceuticals which originally were designed to treat people with neurological and psychiatric conditions, e.g. Alzheimer's disease or attention deficit hyperactivity disorder (ADHD), are nowadays often misused by students as a 'brain doping' substances. These substances are known as nootropic drugs, smart drugs or cognitive enhancers, as they increase memory, attention and concentration of healthy individuals. Since they are easily available illicitly, their consumption is observed to be growing. Currently, these pharmaceuticals started gaining researchers' attention, especially since they have been recently detected in wastewater, surface water and even drinking water. This review summarises the current state of knowledge on nootropic drugs in terms of their population use trends and ethics, occurrence in the environment and detection techniques, toxicity and removal methods, in example of methylphenidate, modafinil and piracetam - three most popular nootropics. It points out that the main sources of knowledge on cognitive enhancers illicit use are often inconsistent questionnaires, which are not supported by wastewater analysis to become more veracious. Simultaneously, the studies concerning toxicity and removal methods of nootropic drugs are still limited and in many cases environmentally irrelevant. Although the prescription rules has been subjected to more strict control in developed countries, regulatory frameworks with regard to their ecosystem occurrence are still lacking and should be introduced. Moreover, the use of environmentally relevant concentrations in toxicity studies should be a standard, leading to proper ecotoxicity risk assessment. Based on this review, it is recommended to routinely monitor nootropics and their metabolites in waste- and surface waters.

Prevalence and correlates of stimulant and depressant pharmacological cognitive enhancement among Norwegian students

AIMS

To assess the prevalence and factors associated with stimulant and depressant pharmacological cognitive enhancement (PCE) drug use among Norwegian students.

DESIGN

In the first wave (T1), 28,553 students were invited to participate, of whom 9370 (32.8%) responded and completed the survey (mean age = 24.9 years, 63.5% female). One year later (T2) those who had responded to some items at T1 were invited to participate in a follow-up survey, where 4783 (47.2%) responded and completed the survey (mean age = 24.8 years, 64.8% female).

RESULTS

Lifetime prevalence of stimulant PCE drug use was 2.1% at T1 and 3.6% at T2. The lifetime prevalence of depressant PCE drug use was 1.5% at T1 and 3.3% at T2. Stimulant PCE drug use at T2 was predicted by low scores on agreeableness and anxiety, high scores on intellect/openness, and alcohol use, and stimulant and depressant PCE drug use at T1; while depressant PCE drug use at T2 was predicted by low scores on extroversion, high scores on conscientiousness, intellect/openness, and anxiety, and stimulant and depressant PCE drug use at T1.

CONCLUSIONS

The rates of stimulant and depressant PCE drug use increased from T1 to T2. Pharmacological cognitive enhancement drug use may be explained by a combination of a motivation for improving academic achievements and a general inclination towards substance use. The current results may suggest that stimulant PCE drug users are more antisocial and indifferent to rules, while depressant PCE drug users are more motivated by coping with stress.

Quality of life of irradiated brain tumor survivors treated with donepezil or placebo: Results of the WFU CCOP research base protocol 91105

Background

The health-related quality of life (HRQL) and fatigue of brain cancer survivors treated with donepezil or placebo for cognitive symptoms after radiation therapy were examined.

Methods

One hundred ninety-eight patients who completed >30 Gy fractionated whole or partial brain irradiation at least 6 months prior to enrollment were randomized to either placebo or donepezil (5 mg for 6 weeks followed by 10 mg for 18 weeks) in a phase 3 trial. A neurocognitive battery, the Functional Assessment of Cancer Therapy-Brain (FACT-Br) and the Functional Assessment of Chronic Illness Therapy (FACIT)-fatigue, was administered at baseline, 12 weeks, and 24 weeks.

Results

At 12 weeks, donepezil resulted in improvements in only emotional functioning (P = .04), with no significant effects at week 24. Associations by level of baseline cognitive symptoms (above or below the median score of the baseline FACT-Br "additional concerns/brain" subscale), indicated that participants with more baseline symptoms who received donepezil versus placebo, showed improvements in social (P = .02) and emotional well-being (P = .038), other concerns/brain (P = .003) and the FACT-Br total score (P = .004) at 12 weeks, but not 24 weeks. However, participants with fewer baseline symptoms randomized to donepezil versus placebo reported lower functional well-being at both 12 (P = .015) and 24 weeks (P = .009), and greater fatigue (P = .02) at 24 weeks.

Conclusions

The positive impact of donepezil on HRQL was greater in survivors reporting more baseline cognitive symptoms. Donepezil had significantly worse effects on fatigue and functional well-being among participants with fewer baseline symptoms. Future interventions with donepezil should target participants with more baseline cognitive complaints to achieve greater therapeutic impact and lessen potential side effects of treatment.

Serotonergic and cholinergic modulation of functional brain connectivity: A comparison between young and older adults

Aging is accompanied by changes in neurotransmission. To advance our understanding of how aging modifies specific neural circuitries, we examined serotonergic and cholinergic stimulation with resting state functional magnetic resonance imaging (RS-fMRI) in young and older adults. The instant response to the selective serotonin reuptake inhibitor citalopram (30 mg) and the acetylcholinesterase inhibitor galantamine (8 mg) was measured in 12 young and 17 older volunteers during a randomized, double blind, placebo-controlled, crossover study. A powerful dataset consisting of 522 RS-fMRI scans was obtained by acquiring multiple scans per subject before and after drug administration. Group × treatment interaction effects on voxelwise connectivity with ten functional networks were investigated (p < .05, FWE-corrected) using a non-parametric multivariate analysis technique with cerebrospinal fluid, white matter, heart rate and baseline measurements as covariates. Both groups showed a decrease in sensorimotor network connectivity after citalopram administration. The comparable findings after citalopram intake are possibly due to relatively similar serotonergic systems in the young and older subjects. Galantamine altered connectivity between the occipital visual network and regions that are implicated in learning and memory in the young subjects. The lack of a cholinergic response in the elderly might relate to the well-known association between cognitive and cholinergic deterioration at older age.

Time related effects on functional brain connectivity after serotonergic and cholinergic neuromodulation

Psychopharmacological research, if properly designed, may offer insight into both timing and area of effect, increasing our understanding of the brain's neurotransmitter systems. For that purpose, the acute influence of the selective serotonin reuptake inhibitor citalopram (30 mg) and the acetylcholinesterase inhibitor galantamine (8 mg) was repeatedly measured in 12 healthy young volunteers with resting state functional magnetic resonance imaging (RS‐fMRI). Eighteen RS‐fMRI scans were acquired per subject during this randomized, double blind, placebo‐controlled, crossover study. Within‐group comparisons of voxelwise functional connectivity with 10 functional networks were examined (P < 0.05, FWE‐corrected) using a non‐parametric multivariate approach with cerebrospinal fluid, white matter, heart rate, and baseline measurements as covariates. Although both compounds did not change cognitive performance on several tests, significant effects were found on connectivity with multiple resting state networks. Serotonergic stimulation primarily reduced connectivity with the sensorimotor network and structures that are related to self‐referential mechanisms, whereas galantamine affected networks and regions that are more involved in learning, memory, and visual perception and processing. These results are consistent with the serotonergic and cholinergic trajectories and their functional relevance. In addition, this study demonstrates the power of using repeated measures after drug administration, which offers the chance to explore both combined and time specific effects. Hum Brain Mapp 38:308–325, 2017. © 2016 Wiley Periodicals, Inc.

A randomized, double-blind, placebo controlled, parallel group, efficacy study of alpha BRAIN® administered orally

OBJECTIVE

Alpha BRAIN® is a nootropic supplement that purports to enhance cognitive functioning in healthy adults. The goal of this study was to investigate the efficacy of this self-described cognitive enhancing nootropic on cognitive functioning in a group of healthy adults by utilizing a randomized, double blind, placebo-controlled design.

METHODS

A total of 63-treatment naïve individuals between 18 and 35 years of age completed the randomized, double-blind, placebo controlled trial. All participants completed a 2-week placebo run in before receiving active product, Alpha BRAIN® or new placebo, for 6 weeks. Participants undertook a battery of neuropsychological tests at randomization and at study completion. Primary outcome measures included a battery of neuropsychological tests and measures of sleep.

RESULTS

Compared with placebo, Alpha BRAIN® significantly improved on tasks of delayed verbal recall and executive functioning. Results also indicated significant time-by-group interaction in delayed verbal recall for the Alpha BRAIN® group.

CONCLUSIONS

The use of Alpha BRAIN® for 6 weeks significantly improved recent verbal memory when compared with controls, in a group of healthy adults. While the outcome of the study is encouraging, this is the first randomized controlled trial of Alpha BRAIN®, and the results merit further study.

A 15-day course of donepezil modulates spectral EEG dynamics related to target auditory stimuli in young, healthy adult volunteers

OBJECTIVE

To identify possible electroencephalographic (EEG) markers of donepezil's effect on cortical activity in young, healthy adult volunteers at the group level.

METHODS

Thirty subjects were administered a daily dose of either 5mg donepezil or placebo for 15days in a double-blind, randomized, cross-over trial. The electroencephalogram during an auditory oddball paradigm was recorded from 58 scalp electrodes. Current source density (CSD) transformations were applied to EEG epochs. The event-related potential (ERP), inter-trial coherence (ITC: the phase consistency of the EEG spectrum) and event-related spectral perturbation (ERSP: the EEG power spectrum relative to the baseline) were calculated for the target (oddball) stimuli.

RESULTS

The donepezil and placebo conditions differed in terms of the changes in delta/theta/alpha/beta ITC and ERSP in various regions of the scalp (especially the frontal electrodes) but not in terms of latency and amplitude of the P300-ERP component.

CONCLUSION

Our results suggest that ITC and ERSP analyses can provide EEG markers of donepezil's effects in young, healthy, adult volunteers at a group level.

SIGNIFICANCE

Novel EEG markers could be useful to assess the therapeutic potential of drug candidates in Alzheimer's disease in healthy volunteers prior to the initiation of Phase II/III clinical studies in patients.

'Drugs That Make You Feel Bad'? Remorse-Based Mitigation and Neurointerventions

In many jurisdictions, an offender's remorse is considered to be a relevant factor to take into account in mitigation at sentencing. The growing philosophical interest in the use of neurointerventions in criminal justice raises an important question about such remorse-based mitigation: to what extent should technologically facilitated remorse be honoured such that it is permitted the same penal significance as standard instances of remorse? To motivate this question, we begin by sketching a tripartite account of remorse that distinguishes cognitive, affective and motivational elements of remorse. We then describe a number of neurointerventions that might plausibly be used to enhance abilities that are relevant to these different elements of remorse. Having described what we term the 'moral value' view of the justification of remorse-based mitigation (according to which remorse-based mitigation is justified insofar as mitigation serves as a deserved form of response to the moral value of the offender's remorse), we then consider whether using neurointerventions to facilitate remorse would undermine its moral value, and thus make it inappropriate to honour such remorse in the criminal justice system. We respond to this question by claiming that the form of moral understanding that is incorporated into a genuinely remorseful response grounds remorse's moral value. In view of this claim, we conclude by arguing that neurointerventions need not undermine remorse's moral value on this approach, and that the remorse that such interventions might facilitate could also be authentic to the recipient of the neurointerventions that we discuss.

Donepezil for Irradiated Brain Tumor Survivors: A Phase III Randomized Placebo-Controlled Clinical Trial

PURPOSE

Neurotoxic effects of brain irradiation include cognitive impairment in 50% to 90% of patients. Prior studies have suggested that donepezil, a neurotransmitter modulator, may improve cognitive function.

PATIENTS AND METHODS

A total of 198 adult brain tumor survivors ≥ 6 months after partial- or whole-brain irradiation were randomly assigned to receive a single daily dose (5 mg for 6 weeks, 10 mg for 18 weeks) of donepezil or placebo. A cognitive test battery assessing memory, attention, language, visuomotor, verbal fluency, and executive functions was administered before random assignment and at 12 and 24 weeks. A cognitive composite score (primary outcome) and individual cognitive domains were evaluated.

RESULTS

Of this mostly middle-age, married, non-Hispanic white sample, 66% had primary brain tumors, 27% had brain metastases, and 8% underwent prophylactic cranial irradiation. After 24 weeks of treatment, the composite scores did not differ significantly between groups (P = .48); however, significant differences favoring donepezil were observed for memory (recognition, P = .027; discrimination, P = .007) and motor speed and dexterity (P = .016). Significant interactions between pretreatment cognitive function and treatment were found for cognitive composite (P = .01), immediate recall (P = .05), delayed recall (P = .004), attention (P = .01), visuomotor skills (P = .02), and motor speed and dexterity (P < .001), with the benefits of donepezil greater for those who were more cognitively impaired before study treatment.

CONCLUSION

Treatment with donepezil did not significantly improve the overall composite score, but it did result in modest improvements in several cognitive functions, especially among patients with greater pretreatment impairments.

Declarative memory

Declarative Memory consists of memory for events (episodic memory) and facts (semantic memory). Methods to test declarative memory are key in investigating effects of potential cognition-enhancing substances--medicinal drugs or nutrients. A number of cognitive performance tests assessing declarative episodic memory tapping verbal learning, logical memory, pattern recognition memory, and paired associates learning are described. These tests have been used as outcome variables in 34 studies in humans that have been described in the literature in the past 10 years. Also, the use of episodic tests in animal research is discussed also in relation to the drug effects in these tasks. The results show that nutritional supplementation of polyunsaturated fatty acids has been investigated most abundantly and, in a number of cases, but not all, show indications of positive effects on declarative memory, more so in elderly than in young subjects. Studies investigating effects of registered anti-Alzheimer drugs, cholinesterase inhibitors in mild cognitive impairment, show positive and negative effects on declarative memory. Studies mainly carried out in healthy volunteers investigating the effects of acute dopamine stimulation indicate enhanced memory consolidation as manifested specifically by better delayed recall, especially at time points long after learning and more so when drug is administered after learning and if word lists are longer. The animal studies reveal a different picture with respect to the effects of different drugs on memory performance. This suggests that at least for episodic memory tasks, the translational value is rather poor. For the human studies, detailed parameters of the compositions of word lists for declarative memory tests are discussed and it is concluded that tailored adaptations of tests to fit the hypothesis under study, rather than "off-the-shelf" use of existing tests, are recommended.

Physiological and neurobehavioral effects of cholinesterase inhibition in healthy adults

INTRODUCTION

Based on common pharmacodynamic mechanisms, recent efforts to develop second generation alternatives for organophosphate (OP) prophylaxis have expanded to include cholinesterase (ChE) inhibiting compounds traditionally approved for use in the treatment of Alzheimer's disease (AD). The primary purpose of this study was to determine the extent to which low-dose huperzine A, galantamine, or donepezil selectively inhibited acetylcholinesterase (AChE) versus butyrylcholinesterase (BChE) activity in healthy adults and whether such inhibition impacted neurobehavioral performance.

METHODS

In addition to hourly red blood cell cholinesterase sampling, neurobehavioral function was assessed before and after a single oral dose of huperzine A (100 or 200 μg), galantamine (4 or 8 mg), donepezil (2.5 or 5mg), or placebo (n=12 subjects per drug/dose).

RESULTS

Compared to placebo, both dosages of huperzine A and galantamine inhibited circulating AChE but not BChE. With the exception of huperzine A (200 μg), which maintained declarative recall performance across sessions, compounds did not improve neurobehavioral performance. Some aspects of neurobehavioral performance correlated with AChE activity, although associations may have reflected time of day effects.

DISCUSSION

Although huperzine A and galantamine significantly inhibited AChE (and likely increased central acetylcholine levels), neither compound improved neurobehavioral performance. The latter was likely due to ceiling effects in this young, healthy test population. Under conditions of reduced cholinergic activity (e.g., Alzheimer's disease), AChE inhibition (and corresponding maintenance of cholinergic tone) could potentially maintain/augment some aspects of neurobehavioral function.

Pharmacological cognitive enhancement-how neuroscientific research could advance ethical debate

There are numerous ways people can improve their cognitive capacities: good nutrition and regular exercise can produce long-term improvements across many cognitive domains, whilst commonplace stimulants such as coffee temporarily boost levels of alertness and concentration. Effects like these have been well-documented in the medical literature and they raise few (if any) ethical issues. More recently, however, clinical research has shown that the off-label use of some pharmaceuticals can, under certain conditions, have modest cognition-improving effects. Substances such as methylphenidate and modafinil can improve capacities such as working memory and concentration in some healthy individuals. Unlike their more mundane predecessors, these methods of “cognitive enhancement” are thought to raise a multitude of ethical issues. This paper presents the six principal ethical issues raised in relation to pharmacological cognitive enhancers (PCEs)—issues such as whether: (1) the medical safety-profile of PCEs justifies restricting or permitting their elective or required use; (2) the enhanced mind can be an “authentic” mind; (3) individuals might be coerced into using PCEs; (4), there is a meaningful distinction to be made between the treatment vs. enhancement effect of the same PCE; (5) unequal access to PCEs would have implications for distributive justice; and (6) PCE use constitutes cheating in competitive contexts. In reviewing the six principal issues, the paper discusses how neuroscientific research might help advance the ethical debate. In particular, the paper presents new arguments about the contribution neuroscience could make to debates about justice, fairness, and cheating, ultimately concluding that neuroscientific research into “personalized enhancement” will be essential if policy is to be truly informed and ethical. We propose an “ethical agenda” for neuroscientific research into PCEs.

Evaluation of symptomatic drug effects in Alzheimer's disease: strategies for prediction of efficacy in humans

In chronic diseases such as Alzheimer's disease (AD), the arsenal of biomarkers available to determine the effectiveness of symptomatic treatment is very limited. Interpretation of the results provided in literature is cumbersome and it becomes difficult to predict their standardization to a larger patient population. Indeed, cognitive assessment alone does not appear to have sufficient predictive value of drug efficacy in early clinical development of AD treatment. In recent years, research has contributed to the emergence of new tools to assess brain activity relying on innovative technologies of imaging and electrophysiology. However, the relevance of the use of these newer markers in treatment response assessment is waiting for validation. This review shows how the early clinical assessment of symptomatic drugs could benefit from the inclusion of suitable pharmacodynamic markers. This review also emphasizes the importance of re-evaluating a step-by-step strategy in drug development.

Effect of cholinergic neurotransmission modulation on visual spatial paired associate learning in healthy human adults

RATIONALE

Use of cross-species neuropsychological paradigms such as visual-spatial paired associate learning (PAL) may allow for a better understanding of underlying neural substrates of memory. Such paradigms, which are often used to guide models of memory in animals, can then be carried forward into humans to provide a basis for evaluation of pharmacologic compounds designed to ameliorate learning and memory impairments in neurologic and psychiatric morbidities.

OBJECTIVES

This double-blind, randomized, crossover trial investigated effects of donepezil, an acetylcholinesterase (AChE) inhibitor, in attenuating scopolamine-induced cognitive impairment using a novel, "process-based" computerized measure of visual-spatial PAL.

RESULTS

In healthy male volunteers, scopolamine (0.6 mg) induced a time-dependent reduction in visual-spatial PAL, with the greatest impairment (Cohen's d = 1.37) observed 2 h after dosing. Cotreatment with donepezil (10 mg) significantly ameliorated scopolamine-induced impairment at the 2-h time point (Cohen's d = 0.66). Process-based analyses revealed a significant impairment in both memory (Cohen's d = 1.37 to 0.50) and executive (Cohen's d = 1 .21 to 0.62) aspects of visual-spatial PAL performance following acute scopolamine challenge, and these reductions were ameliorated by donepezil.

CONCLUSIONS

Acute scopolamine challenge can produce large and robust deficits in visual-spatial PAL, which reflect impairments in both memory and executive processes. Coadministration of a single dose of donepezil can ameliorate these deficits. These results provide support for the use of a visual-spatial PAL test as a pharmacodynamic cognitive marker of central nervous system (CNS)-mediating compounds in humans.

Cognitive function during nicotine withdrawal: Implications for nicotine dependence treatment

Nicotine withdrawal is associated with deficits in neurocognitive function including sustained attention, working memory, and response inhibition. Several convergent lines of evidence suggest that these deficits may represent a core dependence phenotype and a target for treatment development efforts. A better understanding of the mechanisms underlying withdrawal-related cognitive deficits may lead to improve nicotine dependence treatment. We begin with an overview of the neurocognitive effects of withdrawal in rodent and human models, followed by discussion of the neurobehavioral mechanisms that are thought to underlie these effects. We then review individual differences in withdrawal-related neurocognitive effects including genetics, gender, and psychiatric comorbidity. We conclude with a discussion of the implications of this research for developing improved therapies, both pharmacotherapy and behavioral treatments, that target cognitive symptoms of nicotine withdrawal. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.

Effects of donepezil on cognitive performance after sleep deprivation

OBJECTIVES

To identify tasks that were sensitive to a temporary decline in cognitive performance after sleep deprivation and to investigate the ability of the acetylcholinesterase inhibitor donepezil to reverse any sleep deprivation-induced impairment.

METHODS

Thirty healthy volunteers were administered either a 5-mg daily dose of donepezil or placebo for 14-17 days, in a double-blind parallel group design, then underwent either 24 h sleep deprivation or a normal night of sleep in non-blinded crossover, and were subsequently tested on a battery of cognitive tasks designed to measure different components of memory and executive function.

RESULTS

Sleep deprivation selectively impaired performance on several memory tasks whilst also impairing non-memory function on these tasks. Performance on other tasks was spared. Despite partially reversing the decline in subjective alertness associated with sleep deprivation, treatment with donepezil failed to significantly reverse the decline in cognitive performance on any of the tasks.

CONCLUSIONS

The results demonstrate the sensitivity of certain tests, particularly those that measure memory function, to cognitive impairment after sleep deprivation. The inability of donepezil to reverse this performance decline suggests that the sleep deprivation model of cognitive impairment may not be suitable for detecting pro-cognitive effects of cholinergic augmentation.

Acute effects of donepezil in healthy young adults underline the fractionation of executive functioning

The cholinergic system is involved in the modulation of both bottom-up and top-down attentional control. Top-down attention engages multiple executive control processes, but few studies have investigated whether all or selective elements of executive functions are modulated by the cholinergic system. To investigate the acute effects of the pro-cholinergic donepezil in young, healthy volunteers on distinct components of executive functions we conducted a double-blind, placebo-controlled, independent-groups design study including 42 young healthy male participants who were randomly assigned to one of three oral treatments: glucose (placebo), donepezil 5 mg or donepezil 7.5 mg. The test battery included measures of different executive components (shifting, updating, inhibition, dual-task performance, planning, access to long-term memory), tasks that evaluated arousal/vigilance/visuomotor performance, as well as functioning of working memory subsidiary systems. Donepezil improved sustained attention, reaction times, dual-task performance and the executive component of digit span. The positive effects in these executive tasks did not correlate with arousal/visuomotor/vigilance measures. Among the various executive domains investigated donepezil selectively increased dual-task performance in a manner that could not be ascribed to improvement in arousal/vigilance/visuomotor performance nor working memory slave systems. Other executive tasks that rely heavily on visuospatial processing may also be modulated by the cholinergic system.

Cognitive impairment in acquired brain injury: a predictor of rehabilitation outcomes and an opportunity for novel interventions

Cognitive impairment is a common sequela in acquired brain injury and one that predicts rehabilitation outcomes. There is emerging evidence that impairments in cognitive functions can be manipulated by both pharmacologic and nonpharmacologic interventions to improve rehabilitation outcomes. By using stroke as a model for acquired brain injury, we review the evidence that links cognitive impairment to poor rehabilitation outcomes and discuss possible mechanisms to explain this association. Furthermore, we examine nascent promising research that suggests that interventions that target cognitive impairments can lead to better rehabilitation outcomes.

Neurokinin3-R agonism in aged rats has anxiolytic-, antidepressant-, and promnestic-like effects and stimulates ACh release in frontal cortex, amygdala and hippocampus

Neurokinin-3 receptors (NK(3)-R) are localized in brain regions which have been implicated in processes governing learning and memory as well as emotionality. The effects of acute subcutaneous (s.c.) senktide (0.2 and 0.4 mg/kg), a NK(3)-R agonist, were tested in aged (23-25 month old) Wistar rats: (a) in an episodic-like memory test, using an object discrimination task (this is the first study to test for deficits in episodic-like memory in aged rats, since appropriate tests have only recently became available); (b) on parameters of anxiety in an open field test, (c) on indices of depression in the forced swimming test and (d) on the activity of cholinergic neurons of the basal forebrain, using in vivo microdialysis and HPLC. Neither the saline-, nor senktide-treated aged animals, exhibited episodic-like memory. However, the senktide-, but not the vehicle-treated group, exhibited object memory for spatial displacement, a component of episodic memory. Senktide injection also had anxiolytic- and antidepressant-like effects. Furthermore, the active doses of senktide on behavior increased ACh levels in the frontal cortex, amygdala and hippocampus, suggesting a relationship between its cholinergic and behavioral actions. The results indicate cholinergic modulation by the NK(3)-R in conjunction with a role in the processing of memory and emotional responses in the aged rat.

Cholinergic enhancement augments magnitude and specificity of visual perceptual learning in healthy humans

Learning through experience underlies the ability to adapt to novel tasks and unfamiliar environments. However, learning must be regulated so that relevant aspects of the environment are selectively encoded. Acetylcholine (ACh) has been suggested to regulate learning by enhancing the responses of sensory cortical neurons to behaviorally relevant stimuli. In this study, we increased synaptic levels of ACh in the brains of healthy human subjects with the cholinesterase inhibitor donepezil (trade name: Aricept) and measured the effects of this cholinergic enhancement on visual perceptual learning. Each subject completed two 5 day courses of training on a motion direction discrimination task, once while ingesting 5 mg of donepezil before every training session and once while placebo was administered. We found that cholinergic enhancement augmented perceptual learning for stimuli having the same direction of motion and visual field location used during training. In addition, perceptual learning with donepezil was more selective to the trained direction of motion and visual field location. These results, combined with previous studies demonstrating an increase in neuronal selectivity following cholinergic enhancement, suggest a possible mechanism by which ACh augments neural plasticity by directing activity to populations of neurons that encode behaviorally relevant stimulus features.

Phencyclidine withdrawal disrupts episodic-like memory in rats: reversal by donepezil but not clozapine

Episodic memory is the capacity to recall an event in time and place (What? Where? When?). Impaired episodic memory is a debilitating cognitive symptom in schizophrenia but is poorly controlled by currently available antipsychotic drugs. Consistent with glutamatergic abnormality in schizophrenia, the NDMA receptor antagonist, phencyclidine (PCP), induces persistent 'schizophrenia-like' symptoms including memory deficits in humans and rodents and is widely used as an animal model of the disorder. However, in contrast to humans, PCP and PCP withdrawal-induced memory deficits in rodents are reversed by antipsychotic drugs such as clozapine. One possible explanation is that the memory tasks used in animal studies do not simultaneously test the What? Where? When? components that characterize episodic memory in human tasks. We investigated whether subchronic PCP withdrawal disrupts memory in rats in a task that requires simultaneous integration of memory for object, place and context. Rats learn to discriminate objects under specific spatial and contextual conditions analogous to the What? Where? When? components of human episodic memory. We found that PCP withdrawal impaired performance on this task and that the atypical antipsychotic drug clozapine did not reverse this impairment. However the acetylcholinesterase inhibitor (AChEI) donepezil, which has been shown to improve episodic memory in humans did reverse the effect of PCP. This suggests that PCP withdrawal disruption of object-place-context recognition in rats may prove to be a useful model to investigate episodic memory impairment in schizophrenia and supports the suggestion that AChEIs could prove to be a useful pharmacological strategy to specifically treat episodic memory problems in schizophrenia.

Usage trends for memory and vitality-enhancing medicines: A pharmacoepidemiological study involving pharmacists of the Gujarat region

OBJECTIVE

The aim of the study was to explore the trends and rationale of use of memory and vitality-enhancing medicines (MVEM) in the Gujarat region.

MATERIALS AND METHODS

A prospective pharmacoepidemiological study involving pharmacists of Gujarat region was carried out in the year 2005. Pharmacists (n = 351) working in general and Ayurvedic medical stores were selected from 12 districts of Gujarat region. The pharmacists were explained about the objective of the study and were given a pretested, validated questionnaire.

OUTCOME MEASURES

The questionnaire included the questions regarding herbal MVEM used most commonly, percentage sale of herbal MVEM - sold with or without prescriptions - age group of patients and professional groups who used these drugs most commonly.

RESULTS

The number of individuals using MVEM was highest in the age group of 11-20 years (17.54%), followed by the 21-40 years group (17.12%), supporting the results that the professional group of students (17.29%) and the persons of business or service class (15.29%) are the highest users of these medicines. Evaluation of various constituents in the marketed polyherbal MVEM revealed that Brahmi (Bacopa monniera), Shankhpushpi (Evolvulus alsinoides), Ashwangandha (Withania somnifera), Jatamansi (Nardostychos jatamansi), Vacha (Acorus calamus) and Amla (Phyllanthus emblica) were the common ingredients in the polyherbal preparations.

CONCLUSIONS

This study highlights commonly used Ayurvedic medicines that can be explored for safely enhancing memory and vitality performance. Hence, detailed and scientifically designed research on these drugs would help to identify safe and effective drugs for enhancing the same.

Acetylcholinesterase inhibitors and memantine for neuroenhancement in healthy individuals: a systematic review

The term neuroenhancement refers to improvement in the cognitive, emotional and motivational functions of healthy individuals through, inter alia, the use of drugs. Of known interventions, psychopharmacology provides readily available options, such as the anti-dementia drugs, e.g. acetylcholinesterase inhibitors (donepezil, galantamine, rivastigmine) and memantine. Based on a systematic review we found that expectations about the potential of these drugs exceed their actual effects, as has been demonstrated in randomised controlled trials. Both single and repeated dose trials were included in the systematic review, however repeated dose trials have only been conducted for donepezil. In six small trials lasting 14-42 days, the following results emerged: donepezil improved the retention of training on complex aviation tasks and verbal memory for semantically processed words. In one study episodic memory was improved, whereas in others it remained unaffected by donepezil. In a sleep deprivation trial, donepezil reduced the memory and attention deficits resulting from 24h of sleep deprivation. Two studies reported even transient negative effects. Regarding the safety profile of donepezil, these studies found that it was rather well tolerated. In any case, since large longitudinal studies are not available no conclusions can be drawn. Seven small studies about the effects of a single dose of memantine, and one study with a single dose of rivastigmine have been reported. Again, these studies are not adequate to answer our research question. If, as here and elsewhere suggested, the concept of pharmaceutical neuroenhancement is not to be rejected in principle, the decision of healthy individuals to take drugs for the purpose of neuroenhancement should be based on exhaustive information. At the moment, the research that would support or oppose the use of acetylcholinesterase inhibitors and memantine for neuroenhancement by healthy individuals has not yet been performed.

Donepezil improves episodic memory in young individuals vulnerable to the effects of sleep deprivation

STUDY OBJECTIVES

We investigated if donepezil, a long-acting orally administered cholinesterase inhibitor, would reduce episodic memory deficits associated with 24 h of sleep deprivation.

DESIGN

Double-blind, placebo-controlled, crossover study involving 7 laboratory visits over 2 months. Participants underwent 4 functional MRI scans; 2 sessions (donepezil or placebo) followed a normal night's sleep, and 2 sessions followed a night of sleep deprivation.

SETTING

The study took place in a research laboratory.

PARTICIPANTS

26 young, healthy volunteers with no history of any sleep, psychiatric, or neurologic disorders.

INTERVENTIONS

5 mg of donepezil was taken once daily for approximately 17 days.

MEASUREMENTS AND RESULTS

Subjects were scanned while performing a semantic judgment task and tested for word recognition outside the scanner 45 minutes later. Sleep deprivation increased the frequency of non-responses at encoding and impaired delayed recognition. No benefit of donepezil was evident when participants were well rested. When sleep deprived, individuals who showed greater performance decline improved with donepezil, whereas more resistant individuals did not benefit. Accompanying these behavioral effects, there was corresponding modulation of task-related activation in functionally relevant brain regions. Brain regions identified in relation to donepezil-induced alteration in non-response rates could be distinguished from regions relating to improved recognition memory. This suggests that donepezil can improve delayed recognition in sleep-deprived persons by improving attention as well as enhancing memory encoding.

CONCLUSIONS

Donepezil reduced decline in recognition performance in individuals vulnerable to the effects of sleep deprivation. Additionally, our findings demonstrate the utility of combined fMRI-behavior evaluation in psychopharmacological studies.

Responding to requests from adult patients for neuroenhancements: guidance of the Ethics, Law and Humanities Committee

In the last decade, persons who have no diagnosed medical or mental health condition are increasingly seeking and utilizing, for the ostensible purpose of enhancing their memory or cognitive skills, prescription drugs that were originally developed to improve executive function or memory in persons diagnosed with disorders such as attention deficit hyperactivity disorder or Alzheimer disease. Evidence suggests that this practice, now known as neuroenhancement, is gathering momentum. As a result, neurologists may be encountering patients without a diagnosed illness asking for medications with the goal of improving their memory, cognitive focus, or attention span. Strong arguments have been made for and against this practice, often reflecting strongly held convictions concerning the appropriate practice of medicine. The purpose of this report is to provide neurologists with an overview of the ethical, legal, and social issues surrounding the use of pharmaceuticals prescribed to enhance or augment normal cognitive or affective functioning, as well as practical guidance for responding to an adult patient's request for neuroenhancement.

Acute cognitive effects of donepezil in young, healthy volunteers

OBJECTIVE

The acute nootropic potential of donepezil in young healthy volunteers has not been adequately investigated mainly because in previous studies: (1) effects were assessed before peak-plasma concentration (Tmax) was reached; (2) only a few cognitive processes were assessed. Here we investigated a myriad of cognitive effects of augmentation of acetylcholine using an acute dose of donepezil in healthy adults at theoretical Tmax.

METHODS

This was a double-blind, placebo controlled, parallel group design study of cognitive effects of acute oral donepezil (5 mg). Subjects were tested twice after donepezil ingestion: 90 min (time that coincides with previous testing in the literature) and 210 min. (theoretical Tmax). The test battery included tasks that tap cognitive domains that are sensitive to acetylcholine manipulations.

RESULTS

At both testing times donepezil improved long-term recall of prose, objects recall, recall of spatial locations, and integration of objects with their locations, some effects having been related to self-reported mood enhancement. However, improvement of performance in the central executive measure (backward digit span) occurred only at Tmax.

CONCLUSION

Positive cognitive effects of acute donepezil can be observed in various cognitive domains including mood, but its full nootropic potential is more clearly found close to theoretical peak-plasma concentration.

[Neuroethics in clinical practice]

In recent years the ability of neuroscience to identify and intervene in mental functions has progressed immensely, which raises several anthropologic and ethical questions. Meanwhile neuroethics arose as a new interdisciplinary field for critical analysis of neuroscientific actions and ethical reflection on the increasing knowledge of the human brain, with regard to society and politics. This article provides a survey of neuroethical implications for clinical practice.

Identifying and treating cognitive impairment in bipolar disorder

OBJECTIVES

The presence of cognitive deficits has become increasingly appreciated across all phases of bipolar disorder. The present review sought to identify domains of cognitive dysfunction, methods of assessment, discrimination of iatrogenic from illness-specific etiologies, and pharmacologic strategies to manage cognitive problems in patients with bipolar disorder.

METHODS

A selective literature review was performed focusing on studies of descriptive phenomenology and pharmacologic intervention (favoring randomized comparisons when existent but open trials or case reports when not) involving cognition in bipolar disorder populations, healthy volunteers, or other clinical populations. Identification was made of (i) practical strategies for clinical assessment and management of cognitive complaints, (ii) limitations of existing intervention studies, and (iii) recommendations for the design and direction of future research.

RESULTS

Cognitive deficits involving attention, executive function, and verbal memory are evident across all phases of bipolar disorder. Most existing treatment studies involve nonbipolar populations, prompting caution when extrapolating outcomes to individuals with bipolar disorder. Differentiating medication- from illness-induced cognitive dysfunction requires comprehensive assessment with an appreciation for the cognitive domains most affected by specific medications. No current pharmacotherapies substantially improve cognition in bipolar disorder, although preliminary findings suggest some potential value for adjunctive stimulants such as modafinil and novel experimental agents.

CONCLUSIONS

Circumscribed cognitive deficits may be both iatrogenic and intrinsic to bipolar disorder. Optimal management hinges on a knowledge of illness-specific cognitive domains as well as of the beneficial or adverse cognitive profiles of common psychotropic medications.

Methodological improvements in quantifying cognitive change in clinical trials: an example with single-dose administration of donepezil

OBJECTIVES

Change in cognitive function in response to a pharmacologic challenge can be observed with greater sensitivity by employing cognitive tests with optimal psychometric properties and a statistical approach that more accurately accounts for individual variability in performance. To demonstrate this approach we examined the cognitive effects of a single acute dose administration of an acetylcholinesterase inhibitor, donepezil, in healthy older adults and in older adults with mild Alzheimer's disease (AD).

DESIGN

Placebo-controlled crossover study with three separate testing days: baseline, placebo, and donepezil, with assessments at baseline, and 1-, 2-, 3-, 6-, and 8-hrs post-dosing on each day.

SETTING

Early phase I clinical trial.

PARTICIPANTS

15 healthy older adults; 14 older adults with mild Alzheimer's disease.

INTERVENTION

Single acute dose of 5mg donepezil.

MEASUREMENTS

Performance on the Groton Maze Learning Test (GMLT), a computerized neuropsychological measure of spatial working memory and error monitoring.

RESULTS

A single acute dose of donepezil improved GMLT performance in healthy older adults (effect size: 0.83 at 6 hrs post-dosing) and older adults with mild AD (effect size: 0.58 at 3 hrs post-dosing).

CONCLUSION

The GMLT detected cognitive improvement following a single, acute dose administration of donepezil in healthy older adults and older adults with mild AD. The choice of cognitive tests designed for repeated administration, as well as an analytic approach that emphasizes individual-level change in cognitive function, provides a sensitive approach to detecting central nervous system drug penetration and activity of cognitive-enhancing agents.

Errorless practice as a possible adjuvant to donepezil in Alzheimer's disease

Six individuals with probable Alzheimer's disease (AD) participated in a phase 1 study employing a repeated measures, parallel baseline design testing the hypothesis that error-free experience during word production practice combined with an acetyl cholinesterase inhibitor would improve confrontation naming ability. While acetyl cholinesterase inhibitors are safe and delay cognition decline associated with AD, improvement over baseline cognition is less evident; clinically significant cognitive deficits persist and progress. Both animal and clinical research strongly implicate acetylcholine in learning, a form of neuroplasticity. In clinical practice, however, people with AD are given cholinergic medications without concomitant systematic/targeted retraining. In this study six participants with probable AD and taking donepezil participated in targeted word production practice using an errorless learning strategy. Results showed that combining behavioral enrichment training and an acetyl cholinesterase inhibitor resulted in significant improvements in verbal confrontation naming of trained items for three of six participants. Differences in baseline dementia severity, living conditions, and medications may have influenced the training response. Detection of substantial treatment effects in 50% of subjects suggests further language treatment studies in AD in combination with an acetyl cholinesterase inhibitor are warranted and provide useful information on inclusion/exclusion criteria for use in subsequent studies.

Episodic-like and procedural memory impairments in histamine H1 Receptor knockout mice coincide with changes in acetylcholine esterase activity in the hippocampus and dopamine turnover in the cerebellum

We investigated episodic-like (ELM) and procedural memory (PM) in histamine H1 receptor knockout (H1R-KO) mice. In order to relate possible behavioral deficits to neurobiological changes, we examined H1R-KO and wild-type (WT) mice in terms of acetylcholine esterase (AChE) activity in subregions of the hippocampus and AChE and tyrosine hydroxylase (TH) expression in the striatum. Furthermore, we analyzed acetylcholine (ACh), 5-HT and dopamine (DA) levels, including metabolites, in the cerebellum of H1R-KO and WT mice. The homozygous H1R-KO mice showed impaired ELM as compared with the heterozygous H1R-KO and WT mice. The performance of homozygous H1R-KO mice in the ELM task was primarily driven by familiarity-based memory processes. While the homozygous H1R-KO mice performed similar to the heterozygous H1R-KO and WT mice during the acquisition of a PM, as measured with an accelerating rotarod, after a retention interval of 7 days their performance was impaired relative to the heterozygous H1R-KO and WT mice. These findings suggest that, both, ELM and long-term PM are impaired in the homozygous H1R-KO mice. Neurochemical assays revealed that the H1R-KO mice had significantly lower levels of AChE activity in the dentate gyrus (DG) and CA1 subregions of the hippocampus as compared with the WT mice. The homozygous H1R-KO mice also displayed significantly reduced dihydroxyphenylacetic acid (DOPAC) levels and a reduced DOPAC/DA ratio in the cerebellum, suggesting that the DA turnover in the cerebellum is decelerated in homozygous H1R-KO mice. In conclusion, homozygous H1R-KO mice display severe long-term memory deficits in, both, ELM and PM, which coincide with changes in AChE activity in the hippocampus as well as DA turnover in the cerebellum. The importance of these findings for Alzheimer's (AD) and Parkinson's disease (PD) is discussed.

Effects of donepezil on verbal memory after semantic processing in healthy older adults

OBJECTIVE

To learn if acetylcholinesterase inhibitors alter verbal recall by improving semantic encoding in a double-blind randomized placebo-controlled trial.

BACKGROUND

Cholinergic supplementation has been shown to improve delayed recall in adults with Alzheimer disease. With functional magnetic resonance imaging, elderly adults, when compared with younger participants, have reduced cortical activation with semantic processing. There have been no studies investigating the effects of cholinergic supplementation on semantic encoding in healthy elderly adults.

METHOD

Twenty elderly participants (mean age 71.5, SD+/-5.2) were recruited. All underwent memory testing before and after receiving donepezil (5 mg, n=11 or 10 mg, n=1) or placebo (n=8) for 6 weeks. Memory was tested using a Levels of Processing task, where a series of words are presented serially. Subjects were either asked to count consonants in a word (superficially process) or decide if the word was "pleasant" or "unpleasant" (semantically process).

RESULTS

After 6 weeks of donepezil or placebo treatment, immediate and delayed recall of superficially and semantically processed words was compared with baseline performance. Immediate and delayed recall of superficially processed words did not show significant changes in either treatment group. With semantic processing, both immediate and delayed recall performance improved in the donepezil group.

CONCLUSIONS

Our results suggest that when using semantic encoding, older normal subjects may be aided by anticholinesterase treatment. However, this treatment does not improve recall of superficially encoded words.

Cognitive performance of healthy young rats following chronic donepezil administration

RATIONALE

Experimental studies have investigated the effects of chronic donepezil treatment on the behavioral deficits elicited by reduced activity or the loss of cholinergic neurons that occurs in aging or in models of dementia. However, few studies have analyzed the effects of chronic donepezil treatment on the cognitive functions of intact animals.

OBJECTIVES

The cognitive functions of healthy young rats treated chronically with the acetylcholinesterase inhibitor donepezil were evaluated using a wide behavioral test battery.

RESULTS

Chronic treatment with donepezil ameliorated memory functions and explorative strategies, speeded up the acquisition of localizing knowledge, augmented responsiveness to the context, and reduced anxiety levels. However, it did not affect spatial span, modify motivational levels, or influence associative learning.

CONCLUSIONS

The present findings show the specific profile of donepezil action on cognitive functions in the presence of unaltered cholinergic neurotransmission systems.

A randomized, double-blind, placebo-controlled trial of donepezil to improve memory in epilepsy

PURPOSE

To determine whether an acetylcholinesterase inhibitor, such as donepezil, would improve memory or other cognitive/psychological functions in epilepsy patients with subjective memory complaints.

METHODS

Twenty-three epilepsy patients with subjective memory difficulty were randomized to either 3 months of donepezil (10 mg/day) or 3 months of placebo treatment, and then crossed over to the other treatment arm. Patients and physicians were blinded to treatment phase throughout data acquisition. Assessment of memory and other cognitive functions, subjective memory, mood, and self-rated quality of life (QOL) and social functioning was performed at baseline and following completion of both treatment phases. Seizure frequency and severity as well as treatment emergent adverse effects were also monitored.

RESULTS

Donepezil treatment was not associated with improvement in memory or other cognitive functions, mood, social functioning or QOL. Comparable increases in self-rated memory functioning relative to baseline were evident during donepezil and placebo phases. Donepezil treatment was not associated with increased seizure frequency or severity. Similar to group results, analysis of change within individual patients as a function of treatment phase also showed neither significant benefit nor detriment associated with donepezil.

CONCLUSION

This study found no benefit on memory or other cognitive/psychological functions in a heterogeneous group of epilepsy patients with subjective memory difficulty. Further investigation would be required to determine whether individual patients, or those with particular epilepsy syndromes, might benefit from donepezil or other acetylcholinesterase inhibitors, or if a higher dosage might be effective.

True to oneself? Broad and narrow ideas on authenticity in the enhancement debate

Our knowledge of the human brain and the influence of pharmacological substances on human mental functioning is expanding. This creates new possibilities to enhance personality and character traits. Psychopharmacological enhancers, as well as other enhancement technologies, raise moral questions concerning the boundary between clinical therapy and enhancement, risks and safety, coercion and justice. Other moral questions include the meaning and value of identity and authenticity, the role of happiness for a good life, or the perceived threats to humanity. Identity and authenticity are central in the debate on psychopharmacological enhancers. In this paper, I first describe the concerns at issue here as extensively propounded by Carl Elliott. Next, I address David DeGrazia's theory, which holds that there are no fundamental identity-related and authenticity-related arguments against enhancement technologies. I argue, however, that DeGrazia's line of reasoning does not succeed in settling these concerns. His conception of identity does not seem able to account for the importance we attach to personal identity in cases where personal identity is changed through enhancement technology. Moreover, his conception of authenticity does not explain the reason why we find inauthentic values objectionable. A broader approach to authenticity can make sense of concerns about changes in personal identity by means of enhancement technologies.

A new insight on Al-maltolate-treated aged rabbit as Alzheimer's animal model

Lack of an adequate animal model for Alzheimer's disease (AD) has limited an understanding of the pathogenesis of the disease and the development of therapeutic agents targeting key pathophysiological processes. There are undoubtedly few satisfactory animal models for exploring therapies targeting at amyloid beta (Abeta) secretion, deposition, aggregation, and probably the inflammatory response. However, an understanding of the complex events--tau, Abeta, oxidative stress, redox active iron, etc.--involved in the neuronal cell loss is still unclear due to the lack of a suitable animal model system. The use of neurotoxic agents particularly aluminum-organic complexes, especially Al-maltolate, expands the scope of AD research by providing new animal models exhibiting neurodegenerative processes relevant to AD neuropathology. Examination of different species of aged animals including the rapidly advancing transgenic mouse models revealed very limited AD-like pathology. Most other animal models have single event expression such as extracellular Abeta deposition, intraneuronal neurofilamentous aggregation of proteins akin to neurofibrillary tangles, oxidative stress or apoptosis. To date, there are no paradigms of any animal in which all the features of AD were evident. However, the intravenous injection of Al-maltolate into aged New zealand white rabbits results in conditions which mimics a number of neuropathological, biochemical and behavioral changes observed in AD. Such neurodegenerative effects include the formation of intraneuronal neurofilamentous aggregates that are tau positive, immunopositivity of Abeta, presence of redox active iron, oxidative stress and apoptosis, adds credence to the value of this animal model system. The use of this animal model should not be confused with the ongoing controversy regarding the possible role of Al in the neuropathogenesis, a debate which by no means has been concluded. Above all this animal model involving neuropathology induced by Al-maltolate provides a new information in understanding the mechanism of neurodegeneration.