Cerebral correlates of psychotic syndromes in neurodegenerative diseases

Psychosis has been recognized as a common feature in neurodegenerative diseases and a core feature of dementia that worsens most clinical courses. It includes hallucinations, delusions including paranoia, aggressive behaviour, apathy and other psychotic phenomena that occur in a wide range of degenerative disorders including Alzheimer's disease, synucleinopathies (Parkinson's disease, dementia with Lewy bodies), Huntington's disease, frontotemporal degenerations, motoneuron and prion diseases. Many of these psychiatric manifestations may be early expressions of cognitive impairment, but often there is a dissociation between psychotic/behavioural symptoms and the rather linear decline in cognitive function, suggesting independent pathophysiological mechanisms. Strictly neuropathological explanations are likely to be insufficient to explain them, and a large group of heterogeneous factors (environmental, neurochemical changes, genetic factors, etc.) may influence their pathogenesis. Clinico-pathological evaluation of behavioural and psychotic symptoms (PS) in the setting of neurodegenerative and dementing disorders presents a significant challenge for modern neurosciences. Recognition and understanding of these manifestations may lead to the development of more effective preventive and therapeutic options that can serve to delay long-term progression of these devastating disorders and improve the patients' quality of life. A better understanding of the pathophysiology and distinctive pathological features underlying the development of PS in neurodegenerative diseases may provide important insights into psychotic processes in general.     

The Impact of Social Deprivation on Paranoia,Hallucinations, Mania and Depression: The Role of Discrimination Social Support,Stress and Trust

The negative implications of living in a socially unequal society are now well documented. However, there is poor understanding of the pathways from specific environmental risk to symptoms. Here we examine the associations between social deprivation, depression, and psychotic symptoms using the 2007 Adult Psychiatric Morbidity Survey, a cross-sectional dataset including 7,353 individuals. In addition we looked at the mediating role of stress, discrimination, trust and lack of social support. We found that the participants'' neighbourhood index of multiple deprivation (IMD) significantly predicted psychosis and depression. On inspection of specific psychotic symptoms, IMD predicted paranoia, but not hallucinations or hypomania. Stress and trust partially mediated the relationship between IMD and paranoid ideation. Stress, trust and a lack of social support fully mediated the relationship between IMD and depression. Future research should focus on the role deprivation and social inequalities plays in specific manifestations of psychopathology and investigate mechanisms to explain those associations that occur. Targeting the mediating mechanisms through appropriate psychological intervention may go some way to dampen the negative consequences of living in an unjust society; ameliorating economic injustice may improve population mental health.     

综合护理干预对老年住院糖尿病患者影响的临床观察

目的:观察综合护理干预对老年住院糖尿病患者的临床影响,探讨改善老年住院糖尿病患者临床表现及预后的护理方式。方法:选择老年住院糖尿病患者160例,随机均分为对照组和观察组,对照组采取常规专科护理,观察组加行综合护理干预,治疗2周后比较两组患者焦虑自评量表(SAS)和抑郁自评量表(SDS)评分;出院3个月后比较两组患者自我管理和生活质量(GQOL-100)评分结果:治疗2周和出院3个月后,两组患者在上述方面比较,差异具有统计学意义(P<0.01,P<0.05),观察组优于对照组。结论:对老年住院DM患者施行综合护理干预措施,具有积极的临床意义。     

Relationship between oxidative stress and cognitive impairment in the elderly of rural vs. urban communities

Psychological stress and environmental pollution are frequently associated to urban environment and oxidative stress (OxS). Likewise, OxS is a risk factor for cognitive impairment (CI) in the elderly. Therefore, we hypothesized that the prevalence of CI in subjects of the urban area could be higher than in those of the rural area, and linked to higher OxS. The aim of the study was to determine the relationship between OxS and CI in elderly individuals from rural and urban settings in Mexico. Plasmatic TBARS, plasma total antioxidant status, and the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) were measured in 104 urban and 85 rural elderly individuals. Cognitive functions were evaluated through the Mini Mental State Examination. We found a greater proportion of subjects with OxS and CI in urban than in rural areas (25% vs. 9%), with an odds ratio of 5.67 (CI95% 1.14-38.02, p < 0.05). Our findings suggest that the elderly in urban areas have more OxS and a higher risk of developing CI compared with elderly individuals in a rural environment.     

综合护理干预对老年住院糖尿病患者影响的临床观察

目的：观察综合护理干预对老年住院糖尿病患者的临床影响,探讨改善老年住院糖尿病患者临床表现及预后的护理方式。方法：选择老年住院糖尿病患者160例,随机均分为对照组和观察组,对照组采取常规专科护理,观察组加行综合护理干预,治疗2周后比较两组患者焦虑自评量表（SAS）和抑郁自评量表（SDS）评分;出院3个月后比较两组患者自我管理和生活质量（GQOL-100）评分结果：治疗2周和出院3个月后,两组患者在上述方面比较,差异具有统计学意义（P〈0.01,P〈0.05）,观察组优于对照组。结论：对老年住院DM患者施行综合护理干预措施,具有积极的临床意义。     

2月龄和4月龄大鼠制备心肺复苏模型后神经功能评价及亚组评分的比较

目的：本研究旨在选择适合的大鼠,对比2月龄大鼠与4月龄大鼠CPR后神经功能评分及亚组评分,摸索利用不同月龄的大鼠CPR的可行性。方法通过严格监测SD大鼠制备模型过程中的心电、血压生理指标、测定各组大鼠不同时间点的神经功能缺失评分以及神经功能亚组评分、对比制备4月龄和2月龄大鼠心肺复苏模型的稳定性。结果电刺激致室颤,4月龄组大鼠的成模率为87.5％,远高于2月龄组大鼠,而死亡率无差异;在电刺激诱发CA过程中造成的血压变化,4月龄组大鼠明显低于2月龄组大鼠,存在极显著性差异（ P ＜0.01）;4月龄组大鼠与2月龄组大鼠CPR后各时间点的神经功能评分无统计学差异,而4月龄组大鼠与2月龄组大鼠的神经功能亚组评分在不同时间点,存在显著差异（P ＜0.05）,4月龄大鼠与2月龄大鼠对比,心肺复苏后脑损伤的程度加重。结论4月龄大鼠更适合制备心肺复苏模型,该月龄组的大鼠制备模型成模率高,脑损伤程度重,更适合于用于心肺复苏的基础研究及治疗评价。     

蚌埠市蚌山区老年人群骨质疏松症流行病学调查及对跌倒风险和认知功能的影响

摘要 目的：对蚌埠市蚌山区老年人群骨质疏松症进行流行病学调查,并探讨骨质疏松症对跌倒风险和认知功能的影响。方法：于2019年11月~2021年4月采用多阶段分层随机抽样的方法,抽取蚌埠市蚌山区的常住居民,调查老年人群骨质疏松症发生率,共发放960份调查问卷,回收941份,回收率为98.02%。根据有无骨质疏松症分为骨质疏松症组和无骨质疏松症组,观察两组跌倒风险和认知功能状况。应用多因素logistic回归分析老年人群发生骨质疏松症的危险因素和保护因素。结果：941例研究对象中,检查出存在骨质疏松症者325人,发病率为34.54%。根据有无骨质疏松症分为骨质疏松症组（n=325）和无骨质疏松症组（n=616）。单因素分析结果显示,老年人群发生骨质疏松症与乳制品和钙片摄入情况、年龄、连续服用类固醇激素超过3个月情况、骨折史、性别、其他慢性病患病情况、体质量指数、婚姻状况、饮茶情况、每天运动情况有关（P<0.05）。多因素logistic回归性分析,结果显示：年龄≥70岁、性别为女性、连续服用类固醇激素超过3个月情况是老年人群发生骨质疏松症的危险因素,而每天运动情况≥30 min、有乳制品和钙片摄入情况、体质量指数≥24 kg/m²是老年人群发生骨质疏松症的保护因素（P<0.05）。骨质疏松症组的跌倒风险评估工具（FROP-Com）评分高于无骨质疏松症组,跌倒效能量表（MFES）评分低于无骨质疏松症组（P<0.05）。骨质疏松症组的简明精神状态检查量表（MMSE）评分低于无骨质疏松症组,画钟试验（CDT）评分高于无骨质疏松症组（P<0.05）。结论：蚌埠市蚌山区老年人群骨质疏松症患病率较高,且受到年龄、性别、连续服用类固醇激素超过3个月情况等因素的影响,而每天运动情况≥30 min、乳制品和钙片摄入情况、体质量指数≥24 kg/m²可减少骨质疏松症患病率,同时存在骨质疏松症的患者其跌倒风险升高,认知功能下降。     

1590名农村中老年人生存质量调查分析(英文)

目的:采用SF-36量表中文版评价农村中老年人生存质量,并为提高农村中老年人的生存质量和健康水平提供科学依据和建议。方法:采用随机抽样的方法,采用面对面访谈的形式,记分方法参照国际生存质量评价计划(IQOLA)的制定标准,评价其生理和心理健康状况。结果:1590名农村中老年人男性生存质量得分高于女性。经济水平对农村中老年人的生理健康的影响大于对其心理健康的影响。配偶健在的农村中老年人的各维度得分均高于无配偶者。农村中老年人的各维度得分随教育水平的升高呈升高趋势。结论:农村中老年人的生存质量与年龄成负相关,同时也受文化程度和经济水平等多个因素的影响。因而,对农村中老年人这一弱势群体应该给予更多关注。     

Sexual receptivity in hamsters: brain nuclear estrogen and cytosolic progestin receptors after single and multiple steroid treatments and during the estrous cycle

This series of experiments investigated the relationship between various treatments consisting of estradiol benzoate (EB) and progesterone (P) on sexual receptivity and on concentrations of nuclear estrogen receptors (NER) and cytosolic progestin receptors (CPR) in the hypothalamus-preoptic area in female hamsters. The injection of 1 microgram EB at 0 and 24 hr resulted in higher levels of receptivity (after 0.25 or 0.5 mg P), NER and CPR compared to those obtained after a single injection of 2 micrograms EB. Animals treated with 5 micrograms EB at 0 and 24 hr displayed greater levels of receptivity (after 0.5 mg P) and had higher NER concentrations than animals given a single injection of 10 micrograms EB. Groups treated with either 1 microgram EB at 0 hr or 0.5 microgram EB at 0 and 24 hr did not differ and showed low levels of receptivity, NER and CPR, NER and CPR were also measured on each day of the estrous cycle. NER levels rose between Days 1 and 2, again between Days 2 and 3, and remained elevated on Day 4. CPR levels increased between Days 2 and 3, and there was no difference between Days 3 and 4. Taken together, these data suggest that receptivity in hamsters after estrogen exposure is correlated with the accumulation and maintenance of relatively high NER levels and on the induction of CPR. This can be accomplished by a single large injection of EB or by smaller split doses.     

Psychosis as a transdiagnostic and extended phenotype in the general population

A large body of research indicates that weak expressions of positive psychotic symptoms (“psychotic experiences”) can be measured in the general population, and likely represent the behavioural manifestation of distributed multifactorial (genetic and non‐genetic) risk for psychosis. Psychotic experiences are a transdiagnostic phenomenon: the majority of individuals with these experiences have a diagnosis of non‐psychotic disorder, particularly common mental disorder, in which psychotic experiences predict greater illness severity and poorer treatment response. Some of the people with common mental disorder and psychotic experiences will present to mental health services meeting criteria for “clinical high risk”. Treatment of the transdiagnostic dimension of psychosis in individuals with common mental disorder who meet “clinical high risk” criteria thus may improve outcome (which cannot be interpreted as prevention of “schizophrenia”). Subthreshold psychotic experiences are transitory in about 80% of individuals, while around 20% go on to develop persistent psychotic experiences and 7% a psychotic disorder, with an annual transition rate of 0.5‐1%. Persistence is associated, on the one hand, with environmental exposures, particularly childhood trauma, and, on the other, with network‐type dynamic interactions between psychotic experiences themselves (e.g., interactions between hallucinatory experiences and delusional ideation) and between symptom dimensions (e.g., interactions between affective symptoms and psychotic experiences, or interactions between subthreshold negative symptoms and psychotic experiences). The study of psychotic experiences is helping to elucidate the mechanisms by which environmental and genetic influences shape the transdiagnostic expression of psychosis proneness, that is mostly transitory but may first become persistent over time and eventually give rise to transition to a psychotic disorder.     

Gender differences in psychotic bipolar mania

Objective: This study examined gender differences in the prevalence and types of psychotic symptoms in bipolar mania.Methods: Participants were drawn from consecutive admissions to the psychiatric clinic in Chemnitz, Germany, in 2005. The diagnosis of bipolar disorder, manic episode was made within 24 hours of admission, and the severity of mania was assessed using the Young Mania Rating Scale (YMRS) and the German version of the Altman Self-Rating Mania Scale. Data collected for each patient included age at the onset of bipolar illness, number of previous episodes, social functioning between episodes, and duration of hospitalization for the index episode. Based on the Task Force for Methods and Documentation in Psychiatry system, psychotic symptoms were classified as hallucinations (visual, auditory, olfactory, tactile, acousma, somatic); delusions (paranoid, reference, guilt, grandeur, religious, erotomania, hypochondriac, poverty, jealousy); and ego disorder (thought control, thought broadcasting).Results: One hundred thirty-seven women and 109 men met the criteria for an acute manic episode, of whom 93 women and 62 men had psychotic symptoms. Compared with psychotic men, psychotic women had more delusions and hallucinations, both overall and per patient, and more delusions of reference and paranoid delusions. Psychotic women had more mixed states compared with psychotic men. Psychotic women differed from both psychotic men and nonpsychotic women on a number of clinical and social variables: they had higher YMRS scores and more previous episodes of depression despite an earlier onset of illness.Conclusion: Women with bipolar mania exhibited a specific pattern of psychotic symptoms that appeared to be associated with greater severity of the acute episode, more mixed states, and a more severe course of illness.     

Arcuate fasciculus abnormalities and their relationship with psychotic symptoms in schizophrenia

Disruption of fronto-temporal connections involving the arcuate fasciculus (AF) may underlie language processing anomalies and psychotic features such as auditory hallucinations in schizophrenia. No study to date has specifically investigated abnormalities of white matter integrity at particular loci along the AF as well as its regional lateralization in schizophrenia. We examined white matter changes (fractional anisotropy (FA), axial diffusivity (AD), asymmetry indices) along the whole extent of the AF and their relationship with psychotic symptoms in 32 males with schizophrenia and 44 healthy males. Large deformation diffeomorphic metric mapping and Fiber Assignment Continuous Tracking were employed to characterize FA and AD along the geometric curve of the AF. Our results showed that patients with schizophrenia had lower FA in the frontal aspects of the left AF compared with healthy controls. Greater left FA and AD lateralization in the temporal segment of AF were associated with more severe positive psychotic symptoms such as delusions and hallucinations in patients with schizophrenia. Disruption of white matter integrity of the left frontal AF and accentuation of normal left greater than right asymmetry of FA/AD in the temporal AF further support the notion of aberrant fronto-temporal connectivity in schizophrenia. AF pathology can affect corollary discharge of neural signals from frontal speech/motor initiation areas to suppress activity of auditory cortex that may influence psychotic phenomena such as auditory hallucinations and facilitate elaboration of delusional content.     

Childhood Psychosis or Mental Retardation: A Diagnostic Dilemma: I. Psychiatric and Psychological Aspects

A relatively large percentage of children seen at a mental retardation clinic demonstrated psychotic symptoms. The entire group with psychotic manifestations, 62 in all, were reviewed in order to clarify the diagnosis of childhood psychosis or mental retardation. The 1961 British criteria for childhood psychosis were used and are advocated by the authors. Childhood psychosis was the primary diagnosis in 38 cases, and psychosis secondary to brain damage in 24 cases. Onset of the condition under the age of three years and a poor prognosis for social recovery were characteristic of the entire group.Obvious emotional disorder was present in 21 mothers and 14 fathers. There was a continuum in terms of number of psychotic symptoms, level of intelligence and presence of organic signs. It is concluded that there is an overlap between the entities of childhood psychosis and mental retardation.     

Cardiopulmonary resuscitation in a rat model of chronic myocardial ischemia.

Our group has developed a rat model of cardiac arrest and cardiopulmonary resuscitation (CPR). However, the current rat model uses healthy adult animals. In an effort to more closely reproduce the event of cardiac arrest and CPR in humans with chronic coronary disease, a rat model of coronary artery constriction was investigated during cardiac arrest and CPR. Left coronary artery constriction was induced surgically in anesthetized, mechanically ventilated Sprague-Dawley rats. Echocardiography was used to measure global cardiac performance before surgery and 4 wk postsurgery. Coronary constriction provoked significant decreases in ejection fraction, increases in left ventricular end-diastolic volume, and increases left ventricular end-systolic volume at 4 wk postintervention, just before induction of ventricular fibrillation (VF). After 6 min of untreated VF, CPR was initiated on three groups: 1) coronary artery constriction group, 2) sham-operated group, and 3) control group (without preceding surgery). Defibrillation was attempted after 6 min of CPR. All the animals were resuscitated. Postresuscitation myocardial function as measured by rate of left ventricular pressure increase at 40 mmHg and the rate of left ventricular pressure decline was more significantly impaired and left ventricular end-diastolic pressure was greater in the coronary artery constriction group compared with the sham-operated group and the control group. There were no differences in the total shock energy required for successful resuscitation and duration of survival among the groups. In summary, this rat model of chronic myocardial ischemia was associated with ventricular remodeling and left ventricular myocardial dysfunction 4 wk postintervention and subsequently with severe postresuscitation myocardial dysfunction. This model would suggest further clinically relevant investigation on cardiac arrest and CPR.     

不同坡向川西亚高山林木竞争与叶片表型可塑性的关系研究

表型可塑性是植物生长响应外界环境变化的重要表现形式,体现了植物个体在环境胁迫下的适合度。但是关于植物表型可塑性的驱动机制仍然存在很多争议。为了探讨植物表型可塑性的影响因素,以四川省阿坝藏族羌族自治州位于同一海拔梯度但坡向相反的天然次生林为研究对象,分析了不同坡向竞争强度与10种树木叶片功能性状表型可塑性的关系的差异。研究发现：(1)研究样地中阴坡水分和养分资源优于阳坡;(2)阴坡上林木平均种内和种间竞争强度高于阳坡,阴坡上林木种内竞争强度随着树木个体大小的增加而显著性减少,阳坡上林木种内竞争强度却随着个体大小的增加而增加;(3)阴坡上叶片表型可塑性高于阳坡,表型可塑性随着个体大小的增加而增加,在阳坡上却随着个体大小增加而降低。这些结果表明阴坡上水分等资源环境条件优于阳坡,林木生长受到环境资源限制较少。在林木生长过程中,较高的竞争强度引起的资源重叠加剧,尤其是种内竞争强度的变化,从而导致了阴坡上较高的叶片表型可塑性。因为较高的竞争强度,随着林木个体大小的增加,树木需要更高的可塑性赢得竞争优势来获取更多的资源支持生长。但是在阳坡上,资源相对缺乏,环境资源对树木生长的限制降低了叶片表型的可塑...     

Oral health‐related quality of life and nutritional status of institutionalized elderly population aged 60 years and above in Mysore City,India

doi: 10.1111/j.1741‐2358.2012.00651.x Oral health‐related quality of life and nutritional status of institutionalized elderly population aged 60 years and above in Mysore City, India Objective: To assess whether oral health–related quality of life (OHRQoL) is associated with nutritional status in the institutionalised elderly population of Mysore. Background: Malnutrition in the elderly has an evident impact on their general health and quality of life. Analysis of data of the Geriatric Oral Health Assessment Index (GOHAI) and their association with the Mini Nutritional Assessment (MNA) results improves our understanding of the complex relationship between oral health and malnutrition. Materials and methods: The study was conducted among the institutionalised elderly population in Mysore city, Karnataka. Data on socio‐demographic, oral health status were gathered. OHRQoL was evaluated using GOHAI, and malnutrition risk using MNA. Results: Out of 141 elderly, 41.1% were men and 58.9% were women with mean age of 72.2 ± 7.5 years. Mean GOHAI score was 47.03 ± 9.2, with 69.5% had low perception of oral health. Mean MNA score was 9.91 ± 2.4, 15.6% were malnourished, 52.5% were at risk of malnutrition and 31.9% were adequately nourished. A strong association was found between the mean GOHAI and MNA scores. Conclusion: Oral health–related quality of life was associated with nutritional deficit, and it requires a greater integration between dentistry and nutrition in the health promotion of older adults.     

Up-Down Hand Position Switch May Delay the Fatigue of Non-Dominant Hand Position Rescuers and Improve Chest Compression Quality during Cardiopulmonary Resuscitation: A Randomized Crossover Manikin Study

Previous studies have shown improved external chest compression (ECC) quality and delayed rescuer fatigue when the dominant hand (DH) was in contact with the sternum. However, many rescuers prefer placing the non-dominant hand (NH) in contact with the sternum during ECC. We aimed to investigate the effects of up-down hand position switch on the quality of ECC and the fatigue of rescuers during cardiopulmonary resuscitation (CPR). After completion of a review of the standard adult basic life support (BLS) course, every candidate performed 10 cycles of single adult CPR twice on an adult manikin with either a constant hand position (CH) or a switched hand position (SH) in random order at 7-day intervals. The rescuers’ general characteristics, hand positions, physiological signs, fatigue appearance and ECC qualities were recorded. Our results showed no significant differences in chest compression quality for the DH position rescuers between the CH and SH sessions (p>0.05, resp.). And also no significant differences were found for Borg score (p = 0.437) or cycle number (p = 0.127) of fatigue appearance after chest compressions between the two sessions. However, for NH position rescuers, the appearance of fatigue was delayed (p = 0.046), with a lower Borg score in the SH session (12.67 ± 2.03) compared to the CH session (13.33 ± 1.95) (p = 0.011). Moreover, the compression depth was significantly greater in the SH session (39.3 ± 7.2 mm) compared to the CH session (36.3 ± 8.1 mm) (p = 0.015). Our data suggest that the up-down hand position switch during CPR may delay the fatigue of non-dominant hand position rescuers and improve the quality of chest compressions.     

Heat stability of carboxypeptidase R of experimental animals

Carboxypeptidase N (CPN) and carboxypeptidase R (CPR) are present in fresh serum, and cleave C-terminal arginine or lysine residues from bioactive peptides such as anaphylatoxins and kinins resulting in regulation of peptide activity. Although CPN is present in the active form in plasma, CPR is generated from proCPR by trypsin-like enzymes such as thrombin. CPR regulates not only inflammatory peptides but also restricts fibrinolysis. To elucidate the complex role of CPN and CPR in vivo, studies in animal models will be essential. CPR of guinea pig, rat and rabbit decayed at 37 C rapidly as in the case of human CPR. However, at 25 C, CPR of those species decayed to some extent, although human serum CPR did not decay within 60 min. In the presence of thrombin inhibitor, CPR in the sera of animals tested decayed more rapidly than CPR in serum without thrombin inhibitor suggesting that additional generation of CPR may have been prevented during decay evaluation. However, human serum CPR decayed more rapidly in the absence of thrombin inhibitor indicating that thrombin may accelerate the decay in human serum.     

Default Mode Network Connectivity as a Function of Familial and Environmental Risk for Psychotic Disorder

Background

Research suggests that altered interregional connectivity in specific networks, such as the default mode network (DMN), is associated with cognitive and psychotic symptoms in schizophrenia. In addition, frontal and limbic connectivity alterations have been associated with trauma, drug use and urban upbringing, though these environmental exposures have never been examined in relation to DMN functional connectivity in psychotic disorder.

Methods

Resting-state functional MRI scans were obtained from 73 patients with psychotic disorder, 83 non-psychotic siblings of patients with psychotic disorder and 72 healthy controls. Posterior cingulate cortex (PCC) seed-based correlation analysis was used to estimate functional connectivity within the DMN. DMN functional connectivity was examined in relation to group (familial risk), group × environmental exposure (to cannabis, developmental trauma and urbanicity) and symptomatology.

Results

There was a significant association between group and PCC connectivity with the inferior parietal lobule (IPL), the precuneus (PCu) and the medial prefrontal cortex (MPFC). Compared to controls, patients and siblings had increased PCC connectivity with the IPL, PCu and MPFC. In the IPL and PCu, the functional connectivity of siblings was intermediate to that of controls and patients. No significant associations were found between DMN connectivity and (subclinical) psychotic/cognitive symptoms. In addition, there were no significant interactions between group and environmental exposures in the model of PCC functional connectivity.

Discussion

Increased functional connectivity in individuals with (increased risk for) psychotic disorder may reflect trait-related network alterations. The within-network “connectivity at rest” intermediate phenotype was not associated with (subclinical) psychotic or cognitive symptoms. The association between familial risk and DMN connectivity was not conditional on environmental exposure.     

Acute effects of marijuana smoke on complex operant behavior in rhesus monkeys

The acute behavioral effects of marijuana smoke were assessed in rhesus monkeys using a battery of food-reinforced complex operant tasks that included incremental repeated acquisition (IRA, n = 9), conditioned position responding (CPR, n = 8), progressive ratio (PR, n = 8), delayed matching to sample (DMTS, n = 6), and temporal response differentiation responding (TRD, n = 3). Marijuana or placebo smoke was delivered by a specialized face mask 15-min before sessions at exposure levels of 1, 5, 10, and 15 puffs (35cc/puff) or one cigarette smoked to a butt length of approximately 10 mm (approximately 20 puffs). Marijuana smoke caused significant disruptions of performance in all tests except PR after exposure to 10 or more puffs. Generally, response rates decreased or latencies to respond increased. Performance in the PR test was not consistently affected by marijuana exposure. Accuracy of responding was not altered by marijuana smoke at doses lower than those that decreased response rates in the IRA or CPR tests. In the three animals performing under all five schedules, the relative sensitivities for detecting marijuana behavioral effects were DMTS = TRD greater than IRA = CPR greater than PR. These results suggest that performance under operant schedules that are thought to represent some aspect of time perception, short-term memory, learning, motivation, and position discrimination show differential sensitivity to disruption by marijuana smoke, a finding similar to that noted previously for iv THC administration.