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Role of hyperactive cerebellum and motor cortex in Parkinson's disease.

Previous neuroimaging studies have found hyperactivation in the cerebellum and motor cortex and hypoactivation in the basal ganglia in patients with Parkinson's disease (PD) but the relationship between the two has not been established. This study examined whether cerebellar and motor cortex hyperactivation is a compensatory mechanism for hypoactivation in the basal ganglia or is a pathophysiological response that is related to the signs of the disease. Using a BOLD contrast fMRI paradigm PD patients and healthy controls performed automatic and cognitively controlled thumb pressing movements. Regions of interest analysis quantified the BOLD activation in motor areas, and correlations between the hyperactive and hypoactive regions were performed, along with correlations between the severity of upper limb rigidity and BOLD activation. There were three main findings. First, the putamen, supplementary motor area (SMA) and pre-SMA were hypoactive in PD patients. The left and right cerebellum and the contralateral motor cortex were hyperactive in PD patients. Second, PD patients had a significant negative correlation between the BOLD activation in the ipsilateral cerebellum and the contralateral putamen. The correlation between the putamen and motor cortex was not significant. Third, the BOLD activation in the motor cortex was positively correlated with the severity of upper limb rigidity, but the BOLD activation in the cerebellum was not correlated with rigidity. Further, the activation in the motor cortex was not correlated with upper extremity bradykinesia. These findings provide new evidence supporting the hypothesis that hyperactivation in the ipsilateral cerebellum is a compensatory mechanism for the defective basal ganglia. Our findings also provide the first evidence from neuroimaging that hyperactivation in the contralateral primary motor cortex is not a compensatory response but is directly related to upper limb rigidity.

Aged↗

Death in Jonestown: techniques of political control by a paranoid leader.

Jim Jones and Jonestown are discussed from a "political control" point of view. Seven basic techniques of political control are identified: Control of property and income, weakening of family ties, a sociopolitical caste system, control of egression (escape), control of verbal expression, cognitive control and emotional control. Jonestown is identified as a mini-totalitarian state ruled by a delusional and paranoid person.

Famous Persons↗

Cholinergic control of cognitive resources.

In this paper, we describe our approach to the investigation of cholinergic modulation of human information processing. In a continuing series of studies from our laboratories, we have systematically examined the extent to which current psychological models of information processing provide an adequate framework for the interpretation of the modulatory effects of cholinergic agents on cognitive performance measures. We suggest that the data are consistent with the view of attention and memory as processes which operate through a common, limited capacity executive mechanism, rather than separable serial processes described in the traditional modular models of memory.

Animals↗

Effect of long-term glycemic control on cognitive function.

OBJECTIVE: To investigate the relationship between recurrent hypoglycemia and cognitive impairment in insulin-dependent diabetic patients. RESEARCH DESIGN AND METHODS: Seventy patients who were diagnosed as diabetic at age 18 years or older, were under 55 years old, and had no condition likely to affect cognitive abilities were recruited from a diabetic register. Patients were interviewed to obtain information on the frequency of major and minor hypoglycemia. Their cognitive abilities were assessed on tests of premorbid intelligence, current intelligence, reaction time, concentration, memory, and information processing. RESULTS: There was a significant correlation between the apparent decline in intelligence, expressed as the discrepancy between the estimated premorbid and the actual performance intelligence quotient, and the frequency of major hypoglycemic attacks (rs = -0.30; P < 0.01). Comparison of patients with and without recurrent hypoglycemia showed few significant differences in cognitive ability. CONCLUSIONS: Results support previous work that suggests that major hypoglycemic attacks have a significant effect on some aspects of cognitive function, but the clinical importance of this finding remains to be determined.

Adult↗

Executive attention and metacognitive regulation.

Metacognition refers to any knowledge or cognitive process that monitors or controls cognition. We highlight similarities between metacognitive and executive control functions, and ask how these processes might be implemented in the human brain. A review of brain imaging studies reveals a circuitry of attentional networks involved in these control processes, with its source located in midfrontal areas. These areas are active during conflict resolution, error correction, and emotional regulation. A developmental approach to the organization of the anatomy involved in executive control provides an added perspective on how these mechanisms are influenced by maturation and learning, and how they relate to metacognitive activity.

Attention↗

Prefrontal cortex guides context-appropriate responding during language production.

Although language processing is thought to frequently require cognitive control, little is known about the cognitive and neural basis of the control of language. Here, we demonstrate that processing of context by the PFC plays an important role in the control of language comprehension and production. Using a missing letter paradigm and fMRI, we found that increased activation in the PFC (but not in posterior regions), while encoding and maintaining context information, predicted context-appropriate responses. Furthermore, greater selection demands increased activity during responding in the same regions engaged during the encoding and maintenance of context. Overall, as in other cognitive task domains, these results suggest that PFC context processing plays an important role in the control of language.

Adult↗

Neural basis of aging: the penetration of cognition into action control.

Although functional imaging studies have frequently examined age-related changes in neural recruitment during cognitive tasks, much less is known about such changes during motor performance. In the present study, we used functional magnetic resonance imaging to investigate age-related changes in cyclical hand and/or foot movements across different degrees of complexity. Right-handed volunteers (11 young, 10 old) were scanned while performing isolated flexion-extension movements of the right wrist and foot as well as their coordination, according to the "easy" isodirectional and "difficult" nonisodirectional mode. Findings revealed activation of a typical motor network in both age groups, but several additional brain areas were involved in the elderly. Regardless of the performed motor task, the elderly exhibited additional activation in areas involved in sensory processing and integration, such as contralateral anterior insula, frontal operculum, superior temporal gyrus, supramarginal gyrus, secondary somatosensory area, and ipsilateral precuneus. Age-related activation differences during coordination of both segments were additionally observed in areas reflecting increased cognitive monitoring of motor performance, such as the pre-supplementary motor area, pre-dorsal premotor area, rostral cingulate, and prefrontal cortex. In the most complex coordination task, the elderly exhibited additional activation in anterior rostral cingulate and dorsolateral prefrontal cortex, known to be involved in suppression of prepotent response tendencies and inhibitory cognitive control. Overall, these findings are indicative of an age-related shift along the continuum from automatic to more controlled processing of movement. This increased cognitive monitoring of movement refers to enhanced attentional deployment, more pronounced processing of sensory information, and intersensory integration.

Adult↗

Cognitive functions in brain tumor patients.

As effective treatment interventions have increased survival rates, there has been greater awareness that many brain tumor patients experience cognitive dysfunction despite adequate disease control. Cognitive difficulties often have an impact on quality of life and interfere with the patient's ability to function at premorbid levels; however, the incidence of cognitive dysfunction in brain tumor patients is unknown, because it has not been investigated systematically. Future prospective clinical trials in neuro-oncology should include cognitive outcome measures to increase understanding of the contribution of the tumor and the delayed effects of treatment to cognitive dysfunction.

Brain Neoplasms↗

The neural bases of cognitive conflict and control in moral judgment.

Traditional theories of moral psychology emphasize reasoning and "higher cognition," while more recent work emphasizes the role of emotion. The present fMRI data support a theory of moral judgment according to which both "cognitive" and emotional processes play crucial and sometimes mutually competitive roles. The present results indicate that brain regions associated with abstract reasoning and cognitive control (including dorsolateral prefrontal cortex and anterior cingulate cortex) are recruited to resolve difficult personal moral dilemmas in which utilitarian values require "personal" moral violations, violations that have previously been associated with increased activity in emotion-related brain regions. Several regions of frontal and parietal cortex predict intertrial differences in moral judgment behavior, exhibiting greater activity for utilitarian judgments. We speculate that the controversy surrounding utilitarian moral philosophy reflects an underlying tension between competing subsystems in the brain.

Brain↗

Association of minimal thickness of the medial temporal lobe with hippocampal volume, maximal and minimal hippocampal length: volumetric approach with horizontal magnetic resonance imaging scans for evaluation of a diagnostic marker for neuroimaging of Alzheimer's disease.

A 3-D volumetric study of the medial temporal lobe (MTL) was performed to evaluate how a minimum thickness of the MTL (mtMTL), a visually estimated measure, is associated with other MTL measures, maximal and minimal hippocampal length (max-HL, min-HL) and hippocampal volume, all measured with a 3-D device, Neurolucida, in 33 patients with Alzheimer's disease (AD), seven patients with mild cognitive impairment (MCI), and 20 age-matched controls. Cognitive impairment was evaluated with Mini-Mental State examination (MMSE). The T1-weighted horizontal magnetic resonance imaging (MRI) scans with slices 5 mm thick were analyzed with Neurolucida and the mtMTL was measured with visual estimation. The MTL was divided into the amygdala and hippocampus. Max-HL on both sides was longer in controls than in AD and MCI, whereas min-HL and mtMTL were longer in controls than in AD, and no difference was observed between MCI and controls. Similarly hippocampal volume was larger in controls than in AD, and no differences were seen within the MCI and controls. No difference in amygdala and midbrain volumes was observed among AD, MCI and controls. Correlation of MMSE score with min-HL and mtMTL was higher than that with max-HL. Although hippocampal and MTL measures examined here failed to show significant difference between AD and MCI, max-HL could be a diagnostic neuroimaging sign of AD. The high correlation of MMSE with mtMTL as well as with min-HL compared with that with max-HL, also will support neuroimaging diagnosis of AD.

Aged↗

Cognitive aspects of pain and pain control.

The cognitive and cognitive-behavioral approaches have been shown to be very effective in controlling pain and its sequelae both in the laboratory and in the clinical setting. As used in most research and treatment, cognitive approaches are concerned with the way the person perceives, interprets, and relates to his or her pain rather than with the elimination of the pain per se. This article reviews some of the origins of cognitive theory and pain theory, as well as examples of the techniques used and the research support for the approach. Special emphasis is given to self-efficacy, perceived control, and stress inoculation therapy. There is also discussion of some of the limitations of the cognitive approach. The overall conclusion is that the cognitive approach is a powerful and effective one for pain control despite its limitations.

Adaptation, Psychological↗

Catecholaminergic Contributions to Inhibitory Control Following Physical Fatigue: Behavioral and Neurophysiological Findings.

Acute physical fatigue can impair cognitive control, yet its underlying neurochemical mechanisms remain unclear. This study investigated whether catecholaminergic modulation influences behavioral and neural markers of inhibitory control following physical fatigue. Eighteen healthy, recreationally active adults (9 males, 9 females; 23.4&#xa0;&#xb1;&#xa0;2.2&#xa0;years) completed a randomized, triple-blind, placebo-controlled crossover study. On separate visits, participants received methylphenidate (MPH; 20&#xa0;mg; a dopamine and noradrenaline reuptake inhibitor), reboxetine (REB; 8&#xa0;mg; a noradrenaline reuptake inhibitor), or placebo. Physical fatigue was induced by repeated bilateral leg extensions to task failure. Cognitive performance was assessed before and after physical fatigue using a Go/No-Go task with electroencephalographic recording. Behavioral outcomes included reaction time and accuracy, while event-related potentials measured neural stages of response execution and inhibition (N2 and P3). Mixed-effects models were used for statistical analysis. For No-Go trials, a significant MPH&#xa0;&#xd7;&#xa0;Time interaction was observed for accuracy (p&#xa0;=&#xa0;0.008), with improved post-fatigue performance following MPH administration (p&#xa0;=&#xa0;0.048). At the neural level, MPH was associated with shorter fronto-central No-Go N2 latency (p&#xa0;=&#xa0;0.038) and altered fatigue-related changes in No-Go P3 latency (p&#xa0;=&#xa0;0.047). REB did not produce comparable behavioral or neural effects. These findings provide pharmacological evidence that catecholaminergic mechanisms contribute to inhibitory control following physical fatigue. The differential effects of MPH and REB suggest that selective noradrenergic enhancement alone is insufficient to maintain inhibitory control following physical fatigue. Instead, the findings implicate broader&#xa0;dopaminergic and noradrenergic mechanisms, potentially involving alterations in the temporal dynamics of inhibitory processing. TRIAL REGISTRATION: (G095422N and identifier NCT05880342).

Adult↗

Successful management of the obese patient.

Obesity is a chronic disease that affects a substantial number of Americans. Obesity significantly increases a person's risk of cardiovascular diseases and morbidity. Modification of lifestyle behaviors that contribute to obesity (e.g., inappropriate diet and inactivity) is the cornerstone of treatment. Behavior modification involves using such techniques as self-monitoring, stimulus control, cognitive restructuring, stress management and social support to systematically alter obesity-related behaviors. In addition, adjunctive pharmacotherapy can play an important role in the routine medical management of obesity.

Anti-Obesity Agents↗

Perceived self-efficacy and pain control: opioid and nonopioid mechanisms.

In this experiment, we tested for opioid and nonopioid mechanisms of pain control through cognitive means and the relation of opioid involvement to perceived coping efficacy. Subjects were taught cognitive methods of pain control, were administered a placebo, or received no intervention. Their pain tolerance was then measured at periodic intervals after they were administered either a saline solution or naloxone, an opiate antagonist that blocks the effects of endogenous opiates. Training in cognitive control strengthened perceived self-efficacy both to withstand and to reduce pain; placebo medication enhanced perceived efficacy to withstand pain but not reductive efficacy; and neither form of perceived self-efficacy changed without any intervention. Regardless of condition, the stronger the perceived self-efficacy to withstand pain, the longer subjects endured mounting pain stimulation. The findings provide evidence that attenuation of the impact of pain stimulation through cognitive control is mediated by both opioid and nonopioid mechanisms. Cognitive copers administered naloxone were less able to tolerate pain stimulation than were their saline counterparts. The stronger the perceived self-efficacy to reduce pain, the greater was the opioid activation. Cognitive copers were also able to achieve some increase in pain tolerance even when opioid mechanisms were blocked by naloxone, which is in keeping with a nonopioid component in cognitive pain control. We found suggestive evidence that placebo medication may also activate some opioid involvement. Because placebos do not impart pain reduction skills, it was perceived self-efficacy to endure pain that predicted degree of opioid activation.

Female↗

Cognitive influences in postural control of patients with unilateral vestibular loss.

The aim of this study was to investigate the interference between postural control and cognitive processing in patients with surgically confirmed unilateral vestibular lesions. These patients were well-compensated for vestibular lesions with no symptoms of dizziness or definable postural deficit. We hypothesized that attentional processes would play a greater role in postural control of these patients compared to healthy age-matched controls suggesting that successful compensation for a vestibular impairment involves ongoing increased attentional resources, and is not an automatic process. To explore this hypothesis, we used a dual-task paradigm that combined postural challenges with concurrently performed cognitive tasks. The postural conditions were seated, standing on a fixed floor, standing on a sway-referenced floor, and standing on a translating floor. Cognitive tasks were simple, inhibitory, and forced choice reaction time (RT) tasks. Patients had slower RTs compared to the controls under all conditions, including the seated condition. This effect was particularly large for the choice and inhibitory tasks. Both groups had increased RTs as the postural task became more challenging. Postural sway increased similarly in the patients and controls when performing the RT tasks for all postural conditions. These results suggest that patients with vestibular lesions that are well-compensated require increased attention compared to healthy controls; however, this increased demand on attention extends beyond postural control. The site of action may be at the sensory integration level resolving multiple sensory signals for spatial orientation.

Adult↗

Eye guidance in reading: fixation locations within words.

Three broad categories of models of eye movement guidance in reading are described. According to one category, eye movements in reading are not under stimulus or cognitive control; the other two categories indicate that cognitive activities or stimulus characteristics are involved in eye guidance. In this study a number of descriptive analyses of eye movements in reading were carried out. These analyses dealt with fixation locations on letters within words of various lengths, conditional probabilities that a word will be fixed given that a prior word was or was not fixated, and average saccade length as a function of the length of the word to the right of the fixated word. The results of these analyses were supportive of models which suggest that determining where to look next while reading is made on a nonrandom basis.

Eye Movements↗