Patient preferences for elagolix and leuprolide for treating endometriosis-related pain in the United States.

INTRODUCTION: We evaluated elagolix and leuprolide from the patient's perspective for the treatment of endometriosis-related pain. AREA COVERED: Preference weights from a published discrete choice experiment were used to evaluate preferences for treatment profiles simulating elagolix (150 mg/day and 200 mg/twice-daily dosages) and leuprolide for the treatment of moderate to severe endometriosis-related pain. Sensitivity analyses were conducted by varying the range of risk for pregnancy-related problems, moderate to severe hot flashes, and bone fracture across scenarios. EXPERT OPINION: The 200 mg twice daily dosage of elagolix is more likely to be preferred over leuprolide by patients with moderate to severe endometriosis-related pain in all scenarios explored in the evaluation and sensitivity analyses. The probability that an average respondent would select a treatment was sensitive to increases in risk of moderate to severe hot flashes for leuprolide and possible variations in the risk of pregnancy-related problems for both treatments but was not influenced by an increased risk of bone fracture. CONCLUSIONS: Patients' preferences for treatment of endometriosis-related pain should be evaluated using the benefits and risks of each pharmacological option. Respondents were more likely to prefer the treatment profile similar to 200 mg twice daily elagolix over that of leuprolide in all scenarios.

Cognitive correlates of visual hallucinations in dementia associated with Parkinson's disease.

BACKGROUND: There may be a relationship between cognitive impairment and visual hallucinations (VHs) in patients with Parkinson's disease (PD). The objective of this study was to compare the cognitive profile of hallucinating vs. nonhallucinating patients with Parkinson's disease dementia (PDD). METHODS: The cognitive profile of 86 PDD patients with hallucinations was compared with that of a carefully matched PDD group without hallucinations, all drawn from the baseline assessments of the EXPRESS study with rivastigmine. Logistic regression analysis was employed to identify cognitive measures that have an independent relationship with presence of hallucinations. RESULTS: Worse choice reaction time was the only independent predictor of hallucinations in the logistic regression. A further analysis of the reaction time tasks showed that response selection deficit as opposed to stimulus discrimination deficit was the main difference between the groups. DISCUSSION: These results indicate that attentional control is an important cognitive correlate of VHs in patients with PDD.

Reviews: Effects of transdermal rivastigmine on ADAS-cog items in mild-to-moderate Alzheimer's disease.

Alzheimer's disease (AD) patients treated with rivastigmine transdermal patch have shown statistically significant differences versus placebo on the AD Assessment scale-cognitive subscale (ADAS-cog). In this retrospective analysis of a double-blind, placebo- and active-controlled, 24-week clinical trial, the specific effects of rivastigmine patch on individual ADAS-cog items and cognitive domains (memory, language, and praxis) were explored. The mean baseline to week 24 changes were calculated for each ADAS-cog item and domain in this exploratory, hypothesis-generating analysis. Patients on 9.5 mg/24 h rivastigmine patch, 17.4 mg/24 h rivastigmine patch, and 3 to 12 mg/d rivastigmine capsules showed improvements over placebo on the memory and praxis ADAS-cog subscales. The rivastigmine patch groups also showed improvements on the language subscale. Significant differences versus placebo were seen on several individual item scores in the rivastigmine-treated groups. Rivastigmine patch was associated with improvements on the memory, praxis, and language domains of cognition in patients with mild-to-moderate AD.

Efficacy of rivastigmine on executive function in patients with Parkinson's disease dementia.

BACKGROUND AND OBJECTIVE: Rivastigmine is approved in the USA for the treatment of mild to moderate Alzheimer's disease and Parkinson's disease dementia (PDD). Executive function (EF) deficits are a core symptom of PDD. The current objective was to investigate the effects of rivastigmine capsules versus placebo on EF in PDD, focusing on secondary outcome measures from a large, international, randomized, double-blind, placebo-controlled, 24-week trial (EXPRESS, CENA713B2311). METHODS: Secondary outcomes included Delis-Kaplan Executive Function System (D-KEFS) measures of EF. Data from three D-KEFS subtests (Card Sorting, Letter Fluency, Color-Word Interference), plus the Symbol Digit Modalities Test were analyzed in the observed case (OC) population. Changes from baseline in the rivastigmine versus placebo groups were evaluated using the van Elteren test blocking for country. RESULTS: Of 541 patients in the EXPRESS study, 402, 71, 97, and 65 patients provided data for Letter Fluency, Card Sorting and Color-Word Interference subtests, and the Symbol Digit Modalities Test, respectively. On Letter Fluency, rivastigmine was associated with improvements in correct responses, set loss errors, and responses made (all P < 0.05), but not repetition errors. Higher Card Sorting recognition description score (P= 0.03), and more correct substitutions on the Symbol Digit Modalities Test (P= 0.02) were also recorded. CONCLUSION: Rivastigmine was associated with significant improvements over placebo on EF tests evaluating flexibility of thinking, problem solving and planning in patients with PDD. These findings support the hypothesis that rivastigmine may affect frontal subcortical circuits, which potentially contributes to observed clinical improvement associated with EF.

Evaluating rivastigmine in mild-to-moderate Parkinson's disease dementia using ADAS-cog items.

Rivastigmine has been shown to improve cognition in patients with Parkinson's disease dementia (PDD). To further explore the impact of anticholinesterase therapy on PDD, Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) items were assessed in a retrospective analysis of a 24-week, double-blind, placebo-controlled trial of rivastigmine. Mean changes from baseline at week 24 were calculated for ADAS-cog item scores and for 3 cognitive domain scores. A total of 362 patients were randomized to 3 to 12 mg/d rivastigmine capsules and 179 to placebo. Patients with PDD receiving rivastigmine improved versus placebo on items: word recall, following commands, ideational praxis, remembering test instructions, and comprehension of spoken language (P < .05), with standardized mean differences ranging from 0.04 to 0.30. Rivastigmine also showed significant effects versus placebo on all domains: memory, language, and praxis. The ADAS-cog is sensitive to broad cognitive changes in PDD. Overall, rivastigmine was associated with improvements on individual cognitive items and general cognitive domains.

Effects of rivastigmine in Alzheimer's disease patients with and without hallucinations.

Hallucinations in Alzheimer's disease (AD) may indicate greater cortical cholinergic deficits. Rivastigmine has shown larger treatment benefits versus placebo in dementia with Lewy bodies and Parkinson's disease dementia patients with hallucinations. In this retrospective, hypothesis-generating analysis, we investigated whether hallucinations in AD were associated with greater treatment benefits with rivastigmine. Data were pooled from two randomized, double-blind, 6-month, mild-to-moderate AD trials comparing rivastigmine with placebo. Co-primary efficacy parameters were the Alzheimer Disease Assessment Scale-cognitive subscale (ADAS-cog) and Clinician's Interview-Based Impression of Change plus Caregiver Input (CIBIC-plus). Efficacy data were analyzed for two sub-populations: those with and those without hallucinations at baseline. Of 927 patients, 194 (21%) reported hallucinations at baseline. Hallucinators tended to have greater decline on placebo on all outcome measures. On the ADAS-cog, mean rivastigmine - placebo differences of 3.7 points in hallucinators and 2.2 points in non-hallucinators were reported at 6 months (both p < 0.001). In hallucinators, a significant rivastigmine - placebo difference of -1.0 points (a beneficial effect) was seen on the CIBIC-plus at 6 months (p< 0.001). Non-hallucinators showed a smaller significant treatment difference of -0.3 points (p< 0.05). Interaction testing suggested that differences in treatment effects were significant between hallucinators and non-hallucinators. Hallucinations predicted greater treatment responses to oral rivastigmine.

Rivastigmine transdermal patch skin tolerability: results of a 1-year clinical trial in patients with mild-to-moderate Alzheimer's disease.

BACKGROUND AND OBJECTIVES: Transdermal patches provide non-invasive, continuous drug delivery, and offer significant potential advantages over oral treatments. With all transdermal treatments a proportion of patients will experience some form of skin reaction. The rivastigmine patch has been approved for the treatment of mild-to-moderate Alzheimer's disease (AD) since July 2007 in the US. The aim of the component of the trial reported here was to evaluate the skin tolerability of the rivastigmine transdermal patch in patients with mild-to-moderate AD. METHODS: The pivotal IDEAL trial was a 24-week, randomized, double-blind, placebo-controlled, multicentre trial of the efficacy and tolerability of the rivastigmine transdermal patch in 1195 patients with mild-to-moderate AD. This was followed by a 28-week open-label extension. Although not prospectively defined as a secondary assessment, during both phases of the study the condition of the patients' skin at the application site was evaluated. These data are reviewed in this article. RESULTS: During the 24-week, double-blind phase of the study, 89.6% of patients in the target 9.5 mg/24 h patch treatment group had recorded 'no, slight or mild' signs or symptoms for their most severe application-site reaction. Erythema and pruritus were the most commonly reported reactions. No patient in any patch treatment group experienced a skin reaction that was reported as a serious adverse event. In the 9.5 mg/24 h treatment group, 2.4% of patients discontinued treatment due to an application-site reaction. During the 28-week open-label extension, the skin tolerability profile was similar to that seen in the double-blind phase. Overall, 3.7% of patients discontinued treatment due to application-site skin reactions. There was no indication that the severity of the skin reactions increased over time. CONCLUSION: Overall, the data support a favourable skin tolerability profile for the rivastigmine transdermal patch, and provide reassurance that the benefits of rivastigmine patch therapy for patients with AD are not confounded by significant skin irritation problems. Nevertheless, care should be taken to follow manufacturer's advice about patch application, such as daily rotation of the application site, to minimize the risk of skin reactions.

Evaluation of dementia rating scales in Parkinson's disease dementia.

Disease-specific assessments are not currently available for patients with Parkinson's disease dementia (PDD). This study evaluated the criterion-related validity and test-retest reliability of the Alzheimer's Disease Assessment scale cognitive subscale (ADAS-cog) in terms of sensitivity for differentiation between mild and moderate severity impairment in PDD. Six other dementia rating scales and cognitive tests were also examined. A total of 113 patients with PDD or Alzheimer disease were recruited into this 4-week, multicenter study, segregated into 2 severity groups based on Mini-Mental State Examination (MMSE) score. Mean ADAS-cog scores showed a statistically significant separation between mild and moderate severity patients in both dementias (P < .001). For the ADAS-cog, test-retest Spearman correlation coefficients were significant for each dementia type and severity. This study demonstrated the criterion-related validity and test-retest reliability for ADAS-cog in patients with PDD and strong correlations with MMSE. This supports the validity of previous results obtained with these measures in studies of patients with PDD.

Safety and tolerability of the rivastigmine patch: results of a 28-week open-label extension.

The primary objective of the open-label extension was to evaluate the long-term safety and tolerability of a transdermal rivastigmine patch up to 1 year, as a novel approach to treatment in Alzheimer disease. This was a 28-week extension to a 24-week, double-blind, double-dummy, placebo-controlled, and active-controlled study evaluating rivastigmine patches [9.5 mg/24 h (10 cm2) and 17.4 mg/24 h (20 cm2)] and oral capsules (3 to 6 mg twice-daily). Patients entering the extension were switched directly to 9.5 mg/ 24 h rivastigmine patch and increased to 17.4 mg/24 h patch, irrespective of their double-blind study treatment. Primary measures included safety and tolerability assessments, including adverse events and serious adverse events. Of 1195 patients randomized to treatment, 870 (72.8%) completed the double-blind study and entered the open-label extension. During weeks 1 to 4 of the extension, 9.5 mg/24 h rivastigmine patch was well tolerated overall by patients formerly randomized to rivastigmine capsule or patch groups: < or =2.5% reported nausea and < or =1.9% reported vomiting. No unexpected safety issues arose, and skin tolerability was good; similar to the double-blind study. During the 28-week, open-label extension phase, the patch seemed to be well tolerated with a favorable safety profile.

Effects of rivastigmine on tremor and other motor symptoms in patients with Parkinson's disease dementia: a retrospective analysis of a double-blind trial and an open-label extension.

BACKGROUND AND AIM: Rivastigmine is now widely approved for the treatment of mild to moderately severe dementia in Parkinson's disease (PDD). However, since anticholinergic drugs have a role in the management of tremor in patients with Parkinson's disease (PD), concerns have been raised that the use of cholinergic drugs might worsen PD. The current analyses were performed to examine the potential of rivastigmine to affect tremor and other motor symptoms in patients with PDD. METHODS: The safety profile of rivastigmine was evaluated using a database from a 24-week, randomized, double-blind, placebo-controlled trial in 541 PDD patients (362 randomized to rivastigmine, 179 to placebo), and 334 PDD patients who subsequently entered an open-label 24-week extension on rivastigmine. RESULTS: During the double-blind trial, the adverse event (AE) of emerging or worsening tremor was reported in 10.2% of patients in the rivastigmine group, compared with 3.9% in the placebo group (p = 0.012). Tremor was most frequently reported during the titration phase of rivastigmine treatment, although this was not reflected in total motor Unified Parkinson's Disease Rating Scale (UPDRS) part III scores. Dose dependence of this AE was not observed. At the end of the double-blind phase, six (1.7%) rivastigmine-treated patients had discontinued the study because of tremor. In the open-label extension in which all patients received rivastigmine, tremor was reported by 6.9% of patients: 3.8% and 12.2% of whom had previously received double-blind rivastigmine and placebo, respectively (p = 0.006), suggesting that first exposure to rivastigmine leads to a transient increase in tremor. Three (0.9%) of the 334 patients who entered the open-label extension phase discontinued because of tremor. Incidences of worsening parkinsonism, bradykinesia and rigidity were all <5% in both treatment groups (all p-values not statistically significant, rivastigmine vs placebo). In the 48-week observation of rivastigmine treatment, there was no evidence of adverse long-term motor outcomes. Post-hoc analysis showed that similar improvements in the symptoms of dementia, including the ability to perform activities of daily living, were seen regardless of whether exacerbation of tremor was reported during the study. CONCLUSION: Rivastigmine did not induce clinically significant exacerbation of motor dysfunction in patients with PDD. Rest tremor incidence as an AE was a transient phenomenon during dose titration of rivastigmine. There was no indication that exposure to long-term rivastigmine was associated with a worsening of PD.

Effect of rivastigmine on delay to diagnosis of Alzheimer's disease from mild cognitive impairment: the InDDEx study.

OBJECTIVE: To assess the effect of rivastigmine in patients with mild cognitive impairment (MCI) on the time to clinical diagnosis of Alzheimer's disease (AD) and the rate of cognitive decline. METHODS: The study was a double-blind, randomised, placebo-controlled trial of up to 48 months. All patients had MCI operationally defined by having cognitive symptoms, a global clinical dementia rating stage of 0.5, a score of less than 9 on the New York University delayed paragraph recall test, and by not meeting the diagnostic criteria for AD. Primary efficacy variables were time to clinical diagnosis of AD, and change in performance on a cognitive test battery. This study is registered with the US National Institutes of Health clinical trials database (ClinicalTrials.gov), number NCT00000174. FINDINGS: Of 1018 study patients enrolled, 508 were randomly assigned to rivastigmine and 510 to placebo; 17.3% of patients on rivastigmine and 21.4% on placebo progressed to AD (hazard ratio 0.85 [95% CI 0.64-1.12]; p=0.225). There was no significant difference between the rivastigmine and placebo groups on the standardised Z score for the cognitive test battery measured as mean change from baseline to endpoint (-0.10 [95% CI -0.63 to 0.44], p=0.726). Serious adverse events were reported by 141 (27.9%) rivastigmine-treated patients and 155 (30.5%) patients on placebo; adverse events of all types were reported by 483 (95.6%) rivastigmine-treated patients and 472 (92.7%) placebo-treated patients. The predominant adverse events were cholinergic: the frequencies of nausea, vomiting, diarrhoea, and dizziness were two to four times higher in the rivastigmine group than in the placebo group. INTERPRETATION: There was no significant benefit of rivastigmine on the progression rate to AD or on cognitive function over 4 years. The overall rate of progression from MCI to AD in this randomised clinical trial was much lower than predicted. Rivastigmine treatment was not associated with any significant safety concerns.

Early-onset Alzheimer's disease is associated with greater pathologic burden.

Two subtypes of Alzheimer's disease (AD) have been commonly identified: early- and late-onset forms. Previous studies suggest that early-onset AD patients have more neuritic plaques (NPs) and neurofibrillary tangles (NFTs). In the current study, NP and NFT counts were performed for 8 brain regions in 25 subjects with definite AD. A repeated-measures analysis of variance of mean regional NP and NFT counts for early- and late-onset groups was performed. A significant between-subject effect indicating greater overall NP and NFT burden in the early-onset group was observed (NP: F = 6.8, df = 1, P = .015; NFT: F = 7.5, df = 1, P = .012). This analysis supports the hypothesis that early-onset AD is associated with greater pathologic burden than late-onset AD. This suggests that late-onset AD patients have less cognitive reserve than early-onset patients and require fewer pathologic changes to exhibit cognitive deterioration.

Subthreshold depression in patients with Parkinson's disease and dementia--clinical and demographic correlates.

BACKGROUND: About 40% of the patients with Parkinson's disease (PD) have depressive symptoms, either major depression (MD) or subthreshold depression. Depression was found to be associated with age and age at onset of PD, female gender, more severe parkinsonism, in particular with left-sided and akinetic-rigid symptoms, more functional impairment and cognitive impairment.However, the findings are inconsistent and partly contradictory and most of the studies focused on major depression in PD without dementia. The aim of this study was to examine the relationship between subthreshold depression and other clinical features in 538 PD patients with dementia but without MD drawn from a randomized, placebo-controlled multicentre trial of rivastigmine in PD. RESULTS: One hundred and sixteen patients (21%) had subthreshold depression. Depression was associated with a younger age and age at onset and female gender, but not with severity of parkinsonism, cognition or activities of daily living or laterality of motor symptoms. However, in male patients, an association between depression and left-sided parkinsonism was found. CONCLUSION: In contrast to previous findings in PD patients with major depression but without dementia, we found no relationship between subthreshold depression and other clinical symptoms in patients with PDD.

Profile of cognitive impairment in dementia associated with Parkinson's disease compared with Alzheimer's disease.

OBJECTIVE: To compare the profile of cognitive impairment in Alzheimer's disease (AD) with dementia associated with Parkinson's disease (PDD). METHODS: Neuropsychological assessment was performed in 488 patients with PDD and 488 patients with AD using the Mini-Mental State Examination (MMSE) and the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog). Logistic regression analysis was used to investigate whether the diagnosis could be accurately predicted from the cognitive profile. Additionally, the cognitive profiles were compared with a normative group using standardised effect sizes (Cohen's d). RESULTS: Diagnosis was predicted from the cognitive profile, with an overall accuracy of 74.7%. Poor performance of the AD patients on the orientation test in ADAS-cog best discriminated between the groups, followed by poor performance of the PDD patients on the attentional task in MMSE. Both groups showed memory impairment, AD patients performing worse than PDD patients. CONCLUSION: The cognitive profile in PDD differs significantly from that in AD. Performance on tests of orientation and attention are best in differentiating the groups.

Neuropathologic correlates of activities of daily living in Alzheimer disease.

Functional status, reflected by measures of activities of daily living (ADLs), deteriorates as Alzheimer disease (AD) progresses. Decline in activities of daily living may be mediated by executive and frontal lobe dysfunction. The objective of this study was to examine the relationship between activities of daily living and pathologic burden in Alzheimer disease. Twenty two subjects with definite Alzheimer disease were selected from the UCLA ADRC neuropathology database. A total activities of daily living score was derived from the Retrospective Collateral Dementia Interview-Revised (RCDI-R) questionnaire, which was administered to caregivers of autopsied subjects included in the study. Neuritic plaque (NP) and neurofibrillary tangle (NFT) counts were performed for 8 brain regions. There was a significant positive correlation between total activities of daily living score (higher scores indicate more disability) and mean neuritic plaques and neurofibrillary tangle counts (r = 0.671, P = 0.001, and r = 0.542, P = 0.009, resp), as well as CA1 and prosubiculum neuritic plaques and neurofibrillary tangle counts, right and left orbital frontal neuritic plaques counts, and occipital neuritic plaques count. Total activities of daily living score did not correlate with age at death, age at symptom onset, dementia duration, gender, or education. Deteriorating activities of daily living in Alzheimer Disease subjects correlate with greater overall pathologic burden and possibly selectively with involvement of the medial temporal, occipital, and orbital frontal regions.

Neuropathologic correlates of apathy in Alzheimer's disease.

Apathy is the most commonly observed behavioral disturbance in Alzheimer's disease (AD) and has been suggested to be frontally mediated. Neuritic plaque (NP) and neurofibrillary tangle (NFT) counts were performed for 8 brain regions in 29 subjects with definite AD. Neuropsychiatric Inventory (NPI) for autopsied subjects was obtained from questioning of caregivers of subjects included in the study. Chronic apathy and total NPI composite scores correlated with anterior cingulate NFT counts (r = 0.518, p = 0.01, and r = 0.438, p = 0.032). This analysis suggests that chronic apathy in AD correlates with a greater anterior cingulate NFT burden and that chronic behavioral changes are more reflective than acute changes of disease pathology.

Long-term benefits of rivastigmine in dementia associated with Parkinson's disease: an active treatment extension study.

In patients with dementia associated with Parkinson's disease (PD), the efficacy and safety of rivastigmine, an inhibitor of acetylcholinesterase and butyrylcholinesterase, were previously demonstrated in a 24-week double-blind placebo-controlled trial. Our objective was to determine whether benefits were sustained over the long term. Following the double-blind trial, all patients were permitted to enter an active treatment extension study, during which they received rivastigmine 3-12 mg/day. Standard safety assessments were performed. Efficacy assessments included the Alzheimer's Disease Assessment Scale cognitive subscale (ADAS-cog) and other measures of cognition, daily function, neuropsychiatric symptoms, and executive function. Of 433 patients who completed the double-blind trial, 334 entered and 273 completed the active treatment extension. At 48 weeks, the mean ADAS-cog score for the whole group improved by 2 points above baseline. Placebo patients switching to rivastigmine for the active treatment extension experienced a mean cognitive improvement similar to that of the original rivastigmine group during the double-blind trial. The adverse event profile was comparable to that seen in the double-blind trial. Long-term rivastigmine treatment appeared well tolerated and may provide sustained benefits in dementia associated with PD patients who remain on treatment for up to 48 weeks.

Rivastigmine for dementia associated with Parkinson's disease.

BACKGROUND: Cholinergic deficits are prominent in patients who have dementia associated with Parkinson's disease. We investigated the effects of the dual cholinesterase inhibitor rivastigmine in such patients. METHODS: Patients in whom mild-to-moderate dementia developed at least 2 years after they received a clinical diagnosis of Parkinson's disease were randomly assigned to receive placebo or 3 to 12 mg of rivastigmine per day for 24 weeks. Primary efficacy variables were the scores for the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-cog) and Alzheimer's Disease Cooperative Study-Clinician's Global Impression of Change (ADCS-CGIC). Secondary clinical outcomes were the scores for the Alzheimer's Disease Cooperative Study-Activities of Daily Living, the 10-item Neuropsychiatric Inventory, the Mini-Mental State Examination, Cognitive Drug Research power of attention tests, the Verbal Fluency test, and the Ten Point Clock-Drawing test. RESULTS: A total of 541 patients were enrolled, and 410 completed the study. The outcomes were better among patients treated with rivastigmine than among those who received placebo; however, the differences between these two groups were moderate and similar to those reported in trials of rivastigmine for Alzheimer's disease. Rivastigmine-treated patients had a mean improvement of 2.1 points in the score for the 70-point ADAS-cog, from a baseline score of 23.8, as compared with a 0.7-point worsening in the placebo group, from a baseline score of 24.3 (P<0.001). Clinically meaningful improvements in the scores for the ADCS-CGIC were observed in 19.8 percent of patients in the rivastigmine group and 14.5 percent of those in the placebo group, and clinically meaningful worsening was observed in 13.0 percent and 23.1 percent, respectively (mean score at 24 weeks, 3.8 and 4.3, respectively; P=0.007). Significantly better outcomes were seen with rivastigmine with respect to all secondary efficacy variables. The most frequent adverse events were nausea (affecting 29.0 percent of patients in the rivastigmine group and 11.2 percent of those in the placebo group, P<0.001), vomiting (16.6 and 1.7 percent, P<0.001), and tremor (10.2 and 3.9 percent, P=0.01). CONCLUSIONS: In this placebo-controlled study, rivastigmine was associated with moderate improvements in dementia associated with Parkinson's disease but also with higher rates of nausea, vomiting, and tremor.

Frontal-subcortical neuronal circuits and clinical neuropsychiatry: an update.

Frontal-subcortical circuits form the principal network, which mediate motor activity and behavior in humans. Five parallel frontal-subcortical circuits link the specific areas of the frontal cortex to the striatum, basal ganglia and thalamus. These frontal-subcortical circuits originate from the supplementary motor area, frontal eye field, dorsolateral prefrontal region, lateral orbitofrontal region and anterior cingulate portion of the frontal cortex. The open afferent and efferent connections to the frontal-subcortical circuits mediate coordination between functionally similar areas of the brain. Specific chemoarchitecture and multiple neurotransmitter interactions modulate the functional activity of each circuit. Dorsolateral prefrontal circuit lesions cause executive dysfunction, orbitofrontal circuit lesions lead to personality changes characterized by disinhibition and anterior cingulate circuit lesions present with apathy. The neurobiological correlates of neuropsychiatric disorders including depression, obsessive-compulsive disorder, schizophrenia and substance abuse, imply involvement of frontal-subcortical circuits.