Automatic attentional orienting to other people’s gaze in schizophrenia

Explicit tests of social cognition have revealed pervasive deficits in schizophrenia. Less is known of automatic social cognition in schizophrenia. We used a spatial orienting task to investigate automatic shifts of attention cued by another person’s eye gaze in 29 patients and 28 controls. Central photographic images of a face with eyes shifted left or right, or looking straight ahead, preceded targets that appeared left or right of the cue. To examine automatic effects, cue direction was non-predictive of target location. Cue–target intervals were 100, 300, and 800?ms. In non-social control trials, arrows replaced eye-gaze cues. Both groups showed automatic attentional orienting indexed by faster reaction times (RTs) when arrows were congruent with target location across all cue–target intervals. Similar congruency effects were seen for eye-shift cues at 300 and 800?ms intervals, but patients showed significantly larger congruency effects at 800?ms, which were driven by delayed responses to incongruent target locations. At short 100-ms cue–target intervals, neither group showed faster RTs for congruent than for incongruent eye-shift cues, but patients were significantly slower to detect targets after direct-gaze cues. These findings conflict with previous studies using schematic line drawings of eye-shifts that have found automatic attentional orienting to be reduced in schizophrenia. Instead, our data indicate that patients display abnormalities in responding to gaze direction at various stages of gaze processing—reflected by a stronger preferential capture of attention by another person’s direct eye contact at initial stages of gaze processing and difficulties disengaging from a gazed-at location once shared attention is established.     

Theory of mind and joint action in Parkinson’s disease

It has been suggested that the Theory of Mind (ToM) may rely on more basic processes of social cognition, such as action control (e.g., joint action), even if little is known about this relationship. The relationship between ToM and joint action can be studied in patients with Parkinson’s disease (PD), because they are characterized not only by a deficit in ToM (and in its cognitive and affective subcomponents) but also by a deficit in the inhibition of competing responses. Sixty PD patients and 60 matched healthy controls (HCs) performed a go/no-go Flanker task in both joint and individual conditions. Cognitive (Advanced Test or AT) and affective (Emotion Attribution Task or EAT) ToM also were measured. Thirty-five PD patients and matched HCs also performed the standard Flanker task, as a control measure. In patients, only individuals with high AT scores exhibited a joint Flanker effect, whereas in HCs the joint effect was found irrespectively of AT score. Patients with low EAT scores showed a greater interference effect than patients with high scores, whereas the opposite pattern was found for HCs. In regression analysis AT and EAT scores predicted the Flanker effect in the joint condition only. In the standard task, both groups showed a Flanker effect. The role of different fronto-striatal circuits, especially in PD patients, could explain the different involvement of cognitive and affective ToM in joint tasks. The Flanker effect is discussed considering the referential coding account and the attention-focus account as possible candidates to explain joint action effects.     

Eye-Hand Coordination in Aging and in Parkinson’s Disease

Aiming movements to defined target positions were performed as fast and as accurately as possible by younger and older subjects and by patients in the early stages of Parkinson's disease (PD). Movement time and accuracy were tested in two conditions: with and without a centre cue. Older subjects exhibited slower movement time relative to the younger subjects only when the centre cue was present suggesting inefficient feedback processing. The performance of patients with PD was found to be as precise as that of older subjects. The movements of PD subjects, however, were slower in both conditions. Finally, the performance of subjects improved over trials. The data suggest that there is no difference in the nature of the control processes used by older and early-stage PD subjects, but that there is a reduction in the speed of these processes in PD.     

Dysexecutive syndrome in Parkinson’s disease: the GREFEX study

The objectives of this study were to characterize the frequencies and profiles of behavioral and cognitive dysexecutive syndromes in PD (based on validated battery and diagnostic criteria) and to develop a shortened diagnostic battery. Eighty-eight non-demented patients with a diagnosis of PD were examined with an executive validated battery. Using a validated framework, the patients’ test results were interpreted with respect to normative data from 780 controls. A dysexecutive syndrome was observed in 80.6% of the patients [95% confidence interval: 71.1–90.1]. The dysexecutive profile was characterized by prominent impairments in deduction, flexibility, inhibition and initiation in the cognitive domain, and by global hypoactivity with apathy and hyperactivity in the behavioral domain. This finding implies that patients with PD should be assessed with cognitive tests and a validated inventory for behavioral dysexecutive syndromes. A shortened battery (based on three cognitive tests and three behavioral domains) provided high diagnostic accuracy.     

Working memory in healthy aging and in Parkinson’s disease: evidence of interference effects

Focusing on relevant information while suppressing the irrelevant one are critical abilities for different cognitive processes. However, their functioning has been scarcely investigated in the working memory (WM) domain, in both healthy and pathological conditions. The present research aimed to study these abilities in aging and Parkinson’s disease (PD), testing three groups of healthy participants (young, older and elderly) and one of PD patients, employing a new experimental paradigm. Results showed that the transient storing of irrelevant information in WM causes substantial interference effects, which were remarkable in elderly individuals on both response latency and accuracy. Interestingly, PD patients responded faster and were equally accurate compared to a matched control group. Taken together, findings confirm the existence of similar mechanisms for orienting attention inwards to WM contents or outwards to perceptual stimuli, and suggest the suitability of our task to assess WM functioning in both healthy aging and PD.     

Tic douloureux, Parkinson’s disease and the herpes connection

Several cases encountered in psychiatric practice are described in which herpetic involvement of the trigeminal nerve appeared to be crucial to the pathophysiology of the patients’s illness. A brief history of herpes is discussed in terms of the anatomy and physiology of the trigeminal nerve. Particular attention is given to the effects of intraneuronal herpes on gasserian ganglion and spinal nuclei discharge threshoolds, as well as viral pathways directly impacting the substantia nigra. Evidence characterizing Parkinson’s disease as one of several important manifestations of CNS herpes is covered. This article will be presented, by invitation, at the Neuroscience Seminar, Department of Medicine, University of Otago, Dunedin, New Zealand, on 19 August 1997.     

Subjective states associated with retrieval failures in Parkinson’s disease

Instances in which we cannot retrieve information immediately but know that the information might be retrieved later are subjective states that accompany retrieval failure. These are expressed in feeling-of-knowing (FOK) and Tip-of-the-tongue (TOT) experiences. In Experiment 1, participants with Parkinson’s disease (PD) and older adult controls were given general questions and asked to report when they experienced a TOT state and to give related information about the missing word. The PD group experienced similar levels of TOTs but provided less correct peripheral information related to the target when in a TOT state. In Experiment 2, participants were given a Semantic (general knowledge questions) and an Episodic (word pairs) FOK task. PD patients failed to accurately predict their future memory performance (FOK) in response to both episodic and semantic cues. Results are interpreted in the context of recent frameworks of memory and metacognition.     

Possible selves in patients with right- versus left-onset Parkinson’s disease

Possible selves can be used to self-regulate and guide behavior towards what is desired to be achieved or avoided in life. Previous work suggests laterality effects exist within the brain regarding approach and avoidance systems to achieve self-regulation. A modified version of the possible selves task was administered to 45 patients with PD (22 right-onset and 23 left-onset) and 25 community dwelling control subjects (CS). Only 11.1% of patients exhibited balance among their hoped-for and feared possible selves versus 28% of CS. More right-onset patients used a promotion strategy whereas more left-onset patients used a prevention strategy. Patients with left-onset PD thought more about their feared selves, exhibiting reduced goal-directed behavior. Findings among the left-onset group indicate relative dependence of self-regulation on right-sided avoidance brain systems. This may point to an inability to move away from negative outcomes and to work towards rewarding outcomes, which could affect psychological health.     

Self-unawareness of levodopa induced dyskinesias in patients with Parkinson’s disease

The study analyzes the presence of dyskinesias-reduced-self-awareness in forty-eight patients suffering from Parkinson’s disease (PD). As the association with executive dysfunction is a matter of debate and we hypothesize it plays an important role in dyskinesias self-unawareness, we analyzed the role of dopaminergic treatment on the medial-prefrontal-ventral-striatal circuitry using a neurocognitive approach. Special attention was given to metacognitive abilities related to action-monitoring that represent a novel explanation of the phenomenon.PD patients were assessed using different rating scales that we devised to measure movement awareness disorders. In order to ascertain whether each variable measured at a cognitive-clinical level contributes to predicting the scores of the movement-disorder-awareness-scales, we conducted multiple logistic regression models using the latter as binary dependent variables. We used the Wisconsin Card Sorting Test-metacognitive-version to assess the executive functions of the prefrontal-ventral-striatal circuitry.Data showed that a reduction of self-awareness using the Dyskinesia rating scale was associated with global monitoring (p = .04), monitoring resolution (p = .04) and control sensitivity (p = .04). Patients failed to perceive their performance, distinguish between correct and incorrect sorts, be confident in their choice and consequently decide to gamble during the task.We did not find any association with executive functions using the hypo-bradykinesia rating scale.Our findings indicate that when the comparator mechanism for monitoring attentive performance is compromised at a prefrontal striatal level, patients lose the ability to recognize their motor disturbances that do not achieve conscious awareness.     

Emotional state affects gait initiation in individuals with Parkinson’s disease

The purpose of the present study was to determine the impact of manipulating emotional state on gait initiation in persons with Parkinson’s disease (PD) and healthy older adults. Following the presentation of pictures that are known to elicit specific emotional responses, participants initiated gait and continued to walk for several steps at their normal pace. Reaction time, the displacement and velocity of the center of pressure (COP) trajectory during the preparatory postural adjustments, and length and velocity of the first two steps were measured. Analysis of the gait initiation measures revealed that exposure to (1) threatening pictures, relative to all other pictures, speeded the initiation of gait for PD patients and healthy older adults; (2) approach-oriented emotional pictures (erotic and happy people), relative to withdrawal-oriented pictures, facilitated the anticipatory postural adjustments of gait initiation for PD patients and healthy older adults, as evidenced by greater displacement and velocity of the COP movement; and (3) emotional pictures modulated gait initiation parameters in PD patients to the same degree as in healthy older adults. Collectively, these findings hold significant implications for understanding the circuitry underlying the manner by which emotions modulate movement and for the development of emotion-based interventions designed to maximize improvements in gait initiation for individuals with PD.     

Differences in children’s thinking and learning during attentional focus instruction

Considerable evidence supports the motor learning advantage associated with an external focus of attention; however, very few studies have investigated attentional focus effects with children despite individual functional constraints that have the potential to impact use of instructional content. Thus, the purpose of this study was to determine the effect of attentional focus instruction on motor learning in children. Participants (n = 42) aged 9–11 years were randomly assigned to one of three gender-stratified groups: (1) control, (2) internal focus, or (3) external focus. Following initial instructions and task demonstration, participants performed 100 modified free throws over two days while receiving additional cues respective to their attentional focus condition and returned approximately 48 h later to perform 20 additional free throws. Results revealed no significant learning differences between groups. However, responses to retrospective verbal reports suggest that the use of external focus content during practice may have contributed to some participants’ superior performance in retention. Future research should continue to examine attentional focus effects across a variety of ages and incorporate retrospective verbal reports in order to examine children’s thoughts during attentional focus instruction.     

Elementary school children’s attentional biases in physical and numerical space

Numbers are conceptualized spatially along a horizontal mental line. This view is supported by mounting evidence from healthy adults and patients with unilateral spatial neglect. Little is known about children's representation of numbers with respect to space. This study investigated elementary school children's directional biases in physical and numerical space to better understand the relation between space and number. We also examined the nature of spatial organization in numerical space. In two separate tasks, children (n = 57) were asked to bisect a physical line and verbally estimate the midpoint of number pairs. In general, results indicated leftward biases in both tasks, but the degree of deviation did not correlate between the tasks. In the number bisection task, leftward bias (underestimating the midpoint) increased as a function of numerical magnitude and interval between number pairs. In contrast, a rightward deviation was found for smaller number pairs. These findings suggest that different underlying spatial attentional mechanisms might be directed in physical and numerical space in young school children, which would be integrated in adulthood.     

Interaction between color and attentional level in children’s conflict control

Cognitive Processing - Perception of color can affect cognition and behavior in humans. Although there has been increasing interest in the effect of red on cognitive performance in adults, little...     

Psychophysiological and behavioral differences as a function of age and Parkinson’s disease

Differences related to age and to specific neurological (Parkinsonian) damage were studied by contrasting, respectively, old (mean age 64 years) and young (27 years) subjects (N=15), and old-normal (N=15) and old-Parkinsonian (N=15) subjects. Both behavioral as well as psychophysiological dependent variables were employed. The behavioral measure was performance on a discrimination learning task, while the psychophysiological measures were based on habituation to a repeated tone stimulus and on a Pavlovian differential conditioning preparation. The behavioral task showed predominantly age-related differences, with the young learning faster. Another age-related difference was interpreted as showing a more insight-like learning process in the young. Response-bias (beta) values did not differ between groups. Age-related differences also emerged more clearly than specific-neurological-damage differences in the psychophysiological data. The older subjects manifested markedly less autonomic conditioning, which was probably due to a lowering of reactivity, as well as the emergence of habituation to the (loud-noise) unconditional stimulus. A correlational analysis of discrimination conditioning also yielded age-related differences. Most notably, reactivity played a greater role in conditioning in the old than in the young subjects. The results illustrated how psychophysiological measures can provide information that complements those provided by behavioral measures.     

Understanding the role of configural processing in face emotion recognition in Parkinson’s disease

This investigation examined whether impairment in configural processing could explain deficits in face emotion recognition in people with Parkinson’s disease (PD). Stimuli from the Radboud Faces Database were used to compare recognition of four negative emotion expressions by older adults with PD (n = 16) and matched controls (n = 17). Participants were tasked with categorizing emotional expressions from upright and inverted whole faces and facial composites; it is difficult to derive configural information from these two types of stimuli so featural processing should play a larger than usual role in accurate recognition of emotional expressions. We found that the PD group were impaired relative to controls in recognizing anger, disgust and fearful expressions in upright faces. Then, consistent with a configural processing deficit, participants with PD showed no composite effect when attempting to identify facial expressions of anger, disgust and fear. A face inversion effect, however, was observed in the performance of all participants in both the whole faces and facial composites tasks. These findings can be explained in terms of a configural processing deficit if it is assumed that the disruption caused by facial composites was specific to configural processing, whereas inversion reduced performance by making it difficult to derive both featural and configural information from faces.     

Cushing’s disease and melancholia

Striking similarities exist in the endocrinology of Cushing's disease and melancholic depression.Laboratory abnormalities, which have been found in both, include raised urinary,plasma and salivary cortisol, non-suppression of cortisol in the dexamethasone suppression test and adrenocorticotrophin (ACTH) hypersecretion. The hypercortisolism can be so severe in melancholic depression that it is difficult to distinguish from Cushing's disease and has been described as a "pseudo-Cushing's" state. Cerebrospinal fluid corticotrophin-releasing hormone (CRH) levels have been found to be lower in patients with Cushing's disease than in depressed subjects. Dynamic endocrine tests may help to distinguish between the two disorders.An exaggerated response to synacthen has been found in both but a reduced ACTH response to CRH occurs in depression, unlike those with Cushing's disease who show ACTH hyper-responsiveness. Other tests, which may help to distinguish between the two disorders,include the dexamethasone-CRH test, the naloxone test, the insulin-induced hypoglycemia test and the desmopressin stimulation test. Similarities in psychiatric symptoms have been recognised for many years. More recently, the physical complications of melancholic depression have been noted. These include osteoporosis, an increased risk of death from cardiovascular disease, hypertension, a redistribution of fat to intra abdominal sites and insulin resistance. Cushing's disease shares these physical complications and we propose that the common underlying factor is excessive plasma glucocorticoids. The increasing recognition of the physical complications and the increased morbidity and mortality in those who suffer from depression underscores the necessity for early detection and treatment of this illness and screening for undetected physical complications.     

Optimized cuttlefish algorithm for diagnosis of Parkinson’s disease

This paper presents an optimized cuttlefish algorithm for feature selection based on the traditional cuttlefish algorithm, which can be used for diagnosis of Parkinson’s disease at its early stage. Parkinson is a central nervous system disorder, caused due to the loss of brain cells. Parkinson's disease is incurable and could eventually lead to death but medications can help to control symptoms and elongate the patient's life to some extent. The proposed model uses the traditional cuttlefish algorithm as a search strategy to ascertain the optimal subset of features. The decision tree and k-nearest neighbor classifier as a judgment on the selected features. The Parkinson speech with multiple types of sound recordings and Parkinson Handwriting sample’s datasets are used to evaluate the proposed model. The proposed algorithm can be used in predicting the Parkinson’s disease with an accuracy of approximately 94% and help individual to have proper treatment at early stage. The experimental result reveals that the proposed bio-inspired algorithm finds an optimal subset of features, maximizing the accuracy, minimizing number of features selected and is more stable.     

Laterality of repetitive finger movement performance and clinical features of Parkinson’s disease

Impairments in acoustically cued repetitive finger movement often emerge at rates near to and above 2 Hz in persons with Parkinson’s Disease (PD) in which some patients move faster (hastening) and others move slower (bradykinetic). The clinical features impacting this differential performance of repetitive finger movement remain unknown. The purpose of this study was to compare repetitive finger movement performance between the more and less affected side, and the difference in clinical ratings among performance groups. Forty-one participants diagnosed with idiopathic PD completed an acoustically cued repetitive finger movement task while “on” medication. Eighteen participants moved faster, 10 moved slower, and 13 were able to maintain the appropriate rate at rates above 2 Hz. Clinical measures of laterality, disease severity, and the UPDRS were obtained. There were no significant differences between the more and less affected sides regardless of performance group. Comparison of disease severity, tremor, and rigidity among performance groups revealed no significant differences. Comparison of posture and postural instability scores revealed that the participants that demonstrated hastening had worse posture and postural instability scores. Consideration of movement rate during the clinical evaluation of repetitive finger movement may provide additional insight into varying disease features in persons with PD.     

Targeted training of the decision rule benefits rule-guided behavior in Parkinson’s disease

The impact of Parkinson’s disease (PD) on rule-guided behavior has received considerable attention in cognitive neuroscience. The majority of research has used PD as a model of dysfunction in frontostriatal networks, but very few attempts have been made to investigate the possibility of adapting common experimental techniques in an effort to identify the conditions that are most likely to facilitate successful performance. The present study investigated a targeted training paradigm designed to facilitate rule learning and application using rule-based categorization as a model task. Participants received targeted training in which there was no selective-attention demand (i.e., stimuli varied along a single, relevant dimension) or nontargeted training in which there was selective-attention demand (i.e., stimuli varied along a relevant dimension as well as an irrelevant dimension). Following training, all participants were tested on a rule-based task with selective-attention demand. During the test phase, PD patients who received targeted training performed similarly to control participants and outperformed patients who did not receive targeted training. As a preliminary test of the generalizability of the benefit of targeted training, a subset of the PD patients were tested on the Wisconsin card sorting task (WCST). PD patients who received targeted training outperformed PD patients who did not receive targeted training on several WCST performance measures. These data further characterize the contribution of frontostriatal circuitry to rule-guided behavior. Importantly, these data also suggest that PD patient impairment, on selective-attention-demanding tasks of rule-guided behavior, is not inevitable and highlight the potential benefit of targeted training.