Treadmill Gait Analysis Characterizes Gait Alterations in Parkinson's Disease and Amyotrophic Lateral Sclerosis Mouse Models

The effect of anxiety on learning and performance of a complex motor task was determined. In addition the effects of two stressors—competition and failure—and the interactions between these stressors and anxiety were investigated. 40 high and 40 low anxiety Ss (selected by the Taylor Manifest Anxiety Scale) learned and performed a coincident timing task. Competition was presented by offering the Ss a monetary reward for the best performance, while failure was manipulated by giving false knowledge of results and indicating that the performance level was inferior. Results showed that Ss low in anxiety performed significantly better than Ss high in anxiety during the initial learning of a complex motor task. No difference was found between Ss extreme in anxiety once the task was well-learned. Competition and failure did not affect performance or interact with the anxiety level of Ss.     

Electrophysiological correlates of rapid auditory and linguistic processing in adolescents with specific language impairment

Brief tonal stimuli and spoken sentences were utilized to examine whether adolescents (aged 14;3-18;1) with specific language impairments (SLI) exhibit atypical neural activity for rapid auditory processing of non-linguistic stimuli and linguistic processing of verb-agreement and semantic constraints. Further, we examined whether the behavioral and electrophysiological indices for rapid auditory processing were correlated with those for linguistic processing. Fifteen adolescents with SLI and 15 adolescents with normal language met strict criteria for displaying consistent diagnoses from kindergarten through the eighth grade. The findings provide evidence that auditory processing for non-linguistic stimuli is atypical in a significant number of adolescents with SLI compared to peers with normal language and indicate that reduced efficiency in auditory processing in SLI is more vulnerable to rapid rates (200ms ISI) of stimuli presentation (indexed by reduced accuracy, a tendency for longer RTs, reduced N100 over right anterior sites, and reduced amplitude P300). Many adolescents with SLI displayed reduced behavioral accuracy for detecting verb-agreement violations and semantic anomalies, along with less robust P600s elicited by verb-agreement violations. The results indicate that ERPs elicited by morphosyntactic aspects of language processing are atypical in many adolescents with SLI. Additionally, correlational analyses between behavioral and electrophysiological indices of processing non-linguistic stimuli and verb-agreement violations suggest that the integrity of neural functions for auditory processing may only account for a small proportion of the variance in morphosyntactic processing in some adolescents.     

Rhesus monkeys (<Emphasis Type="Italic">Macaca mulatta</Emphasis>) show robust evidence for memory awareness across multiple generalization tests

The possibility that memory awareness occurs in nonhuman animals has been evaluated by providing opportunity to decline memory tests. Current evidence suggests that rhesus monkeys (Macaca mulatta) selectively decline tests when memory is weak (Hampton in Proc Natl Acad Sci USA 98:5359–5362, 2001; Smith et al. in Behav Brain Sci 26:317–374, 2003). However, much of the existing research in nonhuman metacognition is subject to the criticism that, after considerable training on one test type, subjects learn to decline difficult trials based on associative learning of external test-specific contingencies rather than by evaluating the private status of memory or other cognitive states. We evaluated whether such test-specific associations could account for performance by presenting monkeys with a series of generalization tests across which no single association with external stimuli was likely to adaptively control use of the decline response. Six monkeys performed a four alternative delayed matching to location task and were significantly more accurate on trials with a decline option available than on trials without it, indicating that subjects selectively declined tests when memory was weak. Monkeys transferred appropriate use of the decline response under three conditions that assessed generalization: two tests that weakened memory and one test that enhanced memory in a novel way. Bidirectional generalization indicates that use of the decline response by monkeys is not controlled by specific external stimuli but is rather a flexible behavior based on a private assessment of memory.     

Spousal perpetuation of chronic pain behavior

The literature reviewed here demonstrates that spousal response to pain display can reinforce and thereby perpetuate the patient's pain behavior. Relationships characterized as sick-role homeostatis reflect a nexus of behavioral contingencies which are highly resistant to treatment. Though such relationships could developde novo subsequent to accident or injury, modeling and familial effects in chronic pain suggest a rich personal and family history of chronic pain learning experiences. Spousal reinforcement of pain behavior is greater in satisfied relationships and tends to involve contingent attention and caring rather than assistance or taking over tasks and chores. As the vast majority of pain patients and spouses report being satisfied with their marriages, spousal involvement in chronic pain treatment is critical.     

Predicting conjunction typicalities by component typicalities

In two studies, we investigated to what extent typicalities in conjunctive concepts phrased as relative clauses—such aspets that are also birds—can be predicted from simple functions of constituent typicalities and from extensions of such functions. In a first study, analyses of a large aggregated data set, based on seven different experiments, showed that a calibrated minimum rule model and some extensions of this model accounted for a very large part of the variance in the conjunction typicalities. The same models can also account for the so-called guppy effect. A psychological explanation is presented, which states that typicalities in contrast categories, likepets that are not birds andbirds that are not pets, further improve the prediction of conjunction typicalities. This hypothesis is tested in a second study.     

Dissociation of visual localization and visual detection in rhesus monkeys (Macaca mulatta)

Conscious and unconscious cognitive processes contribute independently to human behavior and can be dissociated. For example, humans report failing to see objects clearly in the periphery while simultaneously being able to grasp those objects accurately (Milner in Proc R Soc B Biol Sci 279:2289–2298, 2012). Knowing whether similar dissociations are present in nonverbal species is critical to our understanding of comparative psychology and the evolution of brains. However, such dissociations are difficult to detect in nonhumans because verbal reports of experience are the main way we discriminate putative conscious from unconscious processing. We trained monkeys in a localization task in which they responded to the location where a target appeared, and a matched detection task in which they reported the presence or absence of the same target. We used masking to manipulate the visibility of targets. Accuracy was high in both tasks when stimuli were unmasked and was attenuated by visual masking. At the strongest level of masking, performance in the detection task was at chance, while localization remained significantly above chance. Critically, errors in the detection task were predominantly misses, indicating that the monkeys’ behavior remained under stimulus control, but that the monkeys did not detect the target despite above-chance localization. While these results cannot establish the existence of phenomenal vision in monkeys, the dissociation of visually guided action from detection parallels the dissociation of conscious and unconscious vision seen in humans.