Classical aversive conditioning of heart rate in curarized rats at different blood gas levels

In an effort to examine whether normal blood gas tensions were essential for conditioning, paralyzed rats received a classical aversive heart rate (HR) conditioning session while respirated at different peak expired CO₃ values. After the session, arterial blood was drawn for analysis. That peak expired CO₂ was effective in manipulating Pco₂ was indicated by a significant correlation (r = 0.594, df = 17, P < 0.05). In addition, only rats with blood gas values similar to those of anesthetized controls displayed a discriminated HR CR. These animals also had lower baseline HRs and greater HR variability. Further, 7 of the 9 rats with normal blood gas values were respirated at peak expired CO₂ values from 5.0–5.1 per cent, and no animal ventilated within this range displayed abnormal values. These findings suggest that previous difficulties in obtaining classical and operant conditioning in paralyzed animals may, in part, be attributable to inadequate ventilation.     

Effect of dopamine on diuresis and its role in forming a renal CR

Four female mongrel dogs were used. Three had both ureters transplanted to the surface of the abdomen and one had a unilateral nephrectomy on the left and the right ureter transplanted to the abdomen. In dogs with externalized ureters our results with dopamine show changes in cardiac rate and renal secretion. The method used was 1) injection of dopamine, 2) measurement of subsequent changes in renal secretions (unconditional reflex), 3) and heart rate (HR). After 40 daily injections im of 2.5 mg/kg in normal saline the possible production of a diuretic CR was tested by injecting normal saline im and a tone was used as a signal. The control for normal saline showed no change in HR nor any of the constituents measured. The dopamine injection resulted in an increase of epinephrine in the urine of 300–600 per cent for 45 minutes; of norepinephrine of 200–500 per cent for 45 minutes; of an increase of 50 per cent in urine volume for 45 or more minutes; of absolute Na secretion of 49 per cent, of K, 20 per cent; of creatinine, 39 per cent (average in 3 dogs for 45 minutes diuresis). When the conditional stimulus (normal saline and tone) was given after several months training with the conditional signal and the injection of dopamine, there was no significant CR change to the HR nor any of the above components of urine. The conclusion is that in spite of the great increase of urine volume and composition of above substances there was no significant increase to the signals for the im injection of dopamine,i.e., no conditioning to dopamine.     

Effects of age simulation and age on motor sequence learning: Interaction of age-related cognitive and motor decline

Aging is known to lead to decrements in sensory and cognitive functioning and motor performance. The purpose of the present experiment was twofold: a) We assessed the influence of wearing an age simulation suit on motor sequence learning, cognitive speed tasks and far visual acuity in healthy, younger adults. b) We evaluated the interaction of cognitive aging and declining motor sequence learning in older adults. In a between-subjects design we tested 11 younger adults (M_age = 23.6 years) without the age suit, 12 younger adults wearing the age suit (M_age = 23.2 years), and 23 older adults (M_age = 72.6 years). All participants learned a simple, spatial-temporal movement sequence on two consecutive days, and we assessed perceptual processing speed (Digit Symbol Substitution test and Figural Speed test) and far visual acuity. Wearing an age simulation suit neither affected the learning of the simple motor sequence nor the performance at the cognitive speed tasks in younger adults. However, far visual acuity suffered from wearing the suit. Younger adults with and without the suit showed better motor sequence learning compared to older adults. The significant correlations between the cognitive speed tests and the motor learning performance in older adults indicated that cognitive aging partially explains some of the variance in age-related motor learning deficits.     

An evaluation of carbon dioxide as a short acting anesthetic

The use of carbon dioxide (CO₂) as a quick-acting anesthetic of short duration was studied. Sixteen rats were exposed to a CO₂ atmosphere for 10 and15 sec on separate days. Records were taken of the time required for the administration of intramuscular and gavage injections as well as recovery of motor functions. Recovery following both exposure times was less than 2 min Data are presented that show that there are no prograde effects of CO₂: exposure on subsequent variable-interval (VI-15 sec) behavior.     

Physiologic and motor conditioning and generalization in children with minimal brain dysfunction

Twenty-six children diagnosed as having minimal brain dysfunctions (MBD) were compared with 26 controls in a conditinoing and generalization procedure. Skin resistance, heart rate, and muscle action potentials were monitored throughout. Success involved learning which of two tones signalled the accessibility of a penny. Whereas 92 per cent of controls reached the criterion of five successive correct responses, only 62 per cent of MBD’s did. Further, a third of the MBD’s were so maladaptive as to force procedural variations, while only a few minor irregularities occurred with the controls. Quality of performance was related to age, intelligence, and ability to discriminate and remember tones. Controls were more physiologically reactive than MBD’s, especially in skin resistance. Physiologic differentiation of the two tones was significant in both groups of children and appeared concurrently with motor differentiation. The only evidence of physiologic generalization was in the SR data of controls. The possibility that defective arousal structures, or defective coupling of arousal structures and other perceptual and motor structures, could account for the decreased physiologic reactivity, short attention spans, and poor concentration ofsome MBD’s is discussed. This research, in conformity with other laboratory studies of the brain, indicates that motivational as well as cognitive defects may be organically based.     

Observation system for the control of the hive environment by the honeybee (<Emphasis Type="Italic">Apis mellifera</Emphasis>)

The honeybee can control its hive environment to survive drastic changes in the field environment. To study the control of multiple environmental factors by honeybees, in this experiment, we developed a continual and simultaneous monitoring system for the temperature, moisture, and carbon dioxide (CO₂) concentration in a honeybee hive. Changes in hive weight, CO₂ production rate, and honeybee behavior were also monitored to estimate energy costs and behavioral activity for the environmental regulation. Measurements were conducted in August 2008. We found that the honeybee hive has a microclimate different from the ambient climate, and that the difference was partly accompanied by changes in honeybee activity. Our results also suggest that hive temperature, humidity, and CO₂ concentrations are controlled by different mechanisms. Additional monitoring of the hive environment and honeybee behavior for longer periods would enable us to understand the mechanisms of environmental control by honeybees, which is one of the behaviors that define honeybees as social insects.     

Visuomotor Adaptation and Proprioceptive Recalibration

ABSTRACT

Motor learning, in particular motor adaptation, is driven by information from multiple senses. For example, when arm control is faulty, vision, touch, and proprioception can all report on the arm's movements and help guide the adjustments necessary for correcting motor error. In recent years we have learned a lot about how the brain integrates information from multiple senses for the purpose of perception. However, less is known about how multisensory data guide motor learning. Most models of, and studies on, motor learning focus almost exclusively on the ensuing changes in motor performance without exploring the implications on sensory plasticity. Nor do they consider how discrepancies in sensory information (e.g., vision and proprioception) related to hand position may affect motor learning. Here, we discuss research from our lab and others that shows how motor learning paradigms affect proprioceptive estimates of hand position, and how even the mere discrepancy between visual and proprioceptive feedback can affect learning and plasticity. Our results suggest that sensorimotor learning mechanisms do not exclusively rely on motor plasticity and motor memory, and that sensory plasticity, in particular proprioceptive recalibration, plays a unique and important role in motor learning.     

Impacts of delayed feedback on eco-driving behavior and resulting environmental performance changes

Several ways have been developed and applied to improve the environmental footprint of road transportation while contributing to a better road efficiency and safety. However, independently of these measures, the individual’s behavior as a commuter and/or as a driver is also a major issue that cannot be ignored. As a result, the aim of this paper was to assess the impacts of delayed feedback on driving performance considering indicators such as average speed, excess speeding, extreme braking and acceleration; fuel consumption and CO₂ emissions, among others. Data on driving behavior was collected over a period of 6 months through the use of an on-board device installed in 40 light-duty vehicles in the region of Lisbon, Portugal. Two driving monitoring periods of 3 months each were considered: without feedback (Phase 1) and with feedback (Phase 2). Additionally, the short-term (weekly and bi-weekly) impact of feedback on performance was also assessed.The major findings indicate that both experimental and control groups increased fuel consumption and CO₂ emissions over 5%. Both male and female drivers presented increases in these indicators with female drivers presenting higher values (up to 8%, as opposed to the 4% presented by male drivers). These results are related with increases in the number of accelerations, idling and number of small trips (below 2 km) between monitoring periods. Regarding the immediate impact of feedback on driving behavior, results indicate that when receiving negative feedback (revealing a performance decline), behavior would improve the following week. The opposite was found for positive feedback, with drivers worsening performance after being informed they had improved the previous week. Such findings might give an indication that people react differently to the feedback provided, and might depreciate the information provided when negative results are reached.     

Hopping skill in individuals with Down syndrome: A qualitative and quantitative assessment

IntroductionIndividuals with Down syndrome (DS) show a delayed acquisition of gross motor skills. Among gross motor skills, hopping is a particular form of jumping that can be performed using one leg. Despite its large use during play and physical activity, this skill in adults with DS has not received much attention so far. Here, we aim at investigating hopping skill in adults with DS both from a quantitative and qualitative point of view.MethodsCenter of mass and dominant leg kinematics during hopping over distance were recorded from 24 adult individuals with DS and from 21 typically developed adults (TD) using two inertial measurement units positioned on the posterior aspect of the lower back and on the lateral malleolus of the hopping leg. From linear acceleration and angular velocity signals, hopping frequency (HF), cycle, stance and flight duration (CD, SD, FD), vertical stiffness (K_V) and peak to peak linear acceleration and angular velocities about the cranio-caudal, antero-posterior and medio-lateral axes were extracted. A qualitative process assessment of the hopping skill was carried out using the performance criteria of the test for gross motor development (TGMD-3). The extracted parameters were submitted to analysis of covariance, with stature as a covariate to rule-out possible confounding effects.ResultsThe qualitative assessment highlighted a poorer hopping performance in the DS group compared to the TD group. DS participants showed higher HF and K_V, shorter CD, SD, FD and lower angular velocity about the cranio-caudal axis compared to the TD group. Significant correlations between the temporal parameters of the quantitative assessment and the results of the qualitative assessment were observed.DiscussionThe poorer motor competence in hopping in individuals with DS compared to TD peers may be related to the shorter flight time and higher vertical stiffness observed in TD peers. The adopted instrumental approach, overcoming the limitations of subjective evaluations, represents a promising opportunity to quantify motor competence in hopping.     

An improved respiratory system for curarized rats

A respiratory system is described in which peak expired CO₂ is continuously monitored from curarized rats. Another alteration from previous systems is that an endotracheal tube is used to minimize dead air space. The adequacy of the system was tested by maintaining curarized rats at one level of peak expired CO₂ for varying periods of time and by keeping rats at different peak expired CO₂ levels for a fixed period of time. Results of blood gas analyses indicated that values obtained with this system are similar to values in noncurarized rats, and that manipulation of expired CO₂ is an effective means of altering blood gas values.     

Evidence for model-based action planning in a sequential finger movement task

In this article, the authors examine whether and how humans use model-free, reflexive strategies and model-based, deliberative strategies in motor sequence learning. They asked subjects to perform the grid-sailing task, which required moving a cursor to different goal positions in a 5 × 5 grid using different key-mapping (KM) rules between 3 finger keys and 3 cursor movement directions. The task was performed under 3 conditions: Condition 1, new KM; Condition 2, new goal position with learned KM; and Condition 3, learned goal position with learned KM; with or without prestart delay time. The performance improvement with prestart delay was significantly larger under Condition 2. This result provides evidence that humans implement a model-based strategy for sequential action selection and learning by using previously learned internal model of state transition by actions.     

Effects of 7.5% CO2-Induced Anxiety on Individual Performance During a Group Computer Combat Game

The inhalation of 7.5% CO₂ has been shown to induce cognitive effects similar to anxiety. Sixteen healthy participants (14 male; mean age 25.6 years) inhaled either a mixture of 7.5% CO₂ gas or air while playing a group combat computer game. Participants reported greater feelings of anxiety and fired fewer bullets when inhaling CO₂ compared with air, indicating CO₂-induced anxiety may improve efficiency without task-related decrements. Being able to induce controlled and measured anxiety in group situations by CO₂ inhalation may be a useful technique when evaluating response to stressful situations, such as combat, in simulators or real-life scenarios.     

Estimation of a correlation coefficient from an uncertainty measure

In this paper graphs are given for estimating a correlation _XY from a double-entry table. 2H _r , twice the statisticH _r , relative uncertainty (the average of the ratios of the conditional uncertainty of each variable to its uncertainty) was computed. Mean 2H _r 's were computed from 100 samples for each of several sample sizes and numbers of categories. Graphs relating mean 2H _r to , the estimated correlation, for 3–17 categories to each variable and 3 sample sizes—50, 100, and 500—were constructed. 2.5 per cent and 97.5 per cent fiducial limits curves were constructed for establishing confidence limits on _XY and .The research reported in this paper was conducted by personnel of the Aerospace Medical Research Laboratories, Aerospace Medical Division, Air Force Systems Command, Wright-Patterson AFB, Ohio. Further reproduction is authorized to satisfy the needs of the U. S. Government. This paper has been identified by the Aerospace Medical Research Laboratories as AMRL-TR-66-54.     

Reversible Verbal Memory Integration Deficits in Obstructive Sleep Apnoea

When presented with novel but semantically related elements after learning verbal material, healthy participants tend to endorse these items as previously learned. This reflects the normal integration and association of novel verbal information into long-term memory. How obstructive sleep apnoea (OSA) negatively impacts verbal memory performance, and whether deficits are reversible following positive airway pressure (PAP) treatment, remain elusive. We investigated immediate and delayed OSA- and PAP treatment-related effects on verbal memory integration, using a false memory paradigm. Twenty-three patients with OSA learned lists of words semantically related to target non-presented words (1) at baseline after a polysomnography diagnosis night, (2) after a consecutive polysomnography night under PAP titration, and (3) after three months of compliant PAP treatment. At each session, participants learned 10 different lists of words, each list comprising 15 semantically related items. They had then to recognize 15 minutes later (after an intermediate vigilance task) previously learned words within a list including studied words (learned), unstudied but semantically related items (lures), and non-related unstudied items (controls). Sleep quality and fatigue questionnaires, and psychomotor vigilance tests (PVT) were administered at each session. PAP treatment led to OSA remission and improvement in objective and subjective sleep quality. Crucially, recognition of learned and lure words increased after the first night under treatment and remained stable three months later, suggesting successful memory integration and restoration of semantic processes. No treatment-related outcome was found on PVT performance. OSA exerts a detrimental but PAP-reversible effect on verbal learning and semantic memory integration mechanisms underlying the acquisition of novel memory representations.     

Age effects shrink when motor learning is predominantly supported by nondeclarative,automatic memory processes: Evidence from golf putting

Can motor learning be equivalent in younger and older adults? To address this question, 48 younger (M?=?23.5 years) and 48 older (M?=?65.0 years) participants learned to perform a golf-putting task in two different motor learning situations: one that resulted in infrequent errors or one that resulted in frequent errors. The results demonstrated that infrequent-error learning predominantly relied on nondeclarative, automatic memory processes whereas frequent-error learning predominantly relied on declarative, effortful memory processes: After learning, infrequent-error learners verbalized fewer strategies than frequent-error learners; at transfer, a concurrent, attention-demanding secondary task (tone counting) left motor performance of infrequent-error learners unaffected but impaired that of frequent-error learners. The results showed age-equivalent motor performance in infrequent-error learning but age deficits in frequent-error learning. Motor performance of frequent-error learners required more attention with age, as evidenced by an age deficit on the attention-demanding secondary task. The disappearance of age effects when nondeclarative, automatic memory processes predominated suggests that these processes are preserved with age and are available even early in motor learning.     

The nootropic properties of ginseng saponin Rb<Subscript>1</Subscript> are linked to effects on anxiety

Previous studies have shown that crude ginseng extracts enhance performance on shock-motivated tasks. Whether such performance enhancements are due to memory-enhancing (nootropic) properties of ginseng, or to other non-specific effects such as an influence on anxiety has not been determined. In the present study, we evaluated both the nootropic and anxiolytic effects of the ginseng saponin Rb₁. In the first experiment, 80 five-day-old male chicks received intraperitoneal injections of 0, 0.25, 2.5 or 5.0 mg/kg Rb₁. Performance on a visual discrimination task was uvaluted 15 minutes, 24 and 72 hours later. Acquisition of a visual discrimination task was unaffected by drug treatment, but the number of errors was significantly reduced in the 0.25 mg/kg group during retention trials completed 24 and 72 hours after injection. Animals receiving higher dosages showed trends towards enhancement initially, but demonstrated impaired performance when tested 72 hours later. Rb₁ had no effect on response rates or body weight. In the second experiment, 64 five-day-old male chicks received similar injections of Rb₁ (0, 0.25, 2.5 or 5.0 mg/kg) and separation distress was evaluated 15 minutes, 24 and 72 hours later. Rb₁ produced a change in separation distress that depended on the dose and environmental condition under which distress was recorded. These data suggest that Rb₁ can improve memory for a visual discrimination task and that the nootropic effect may be related to changes in anxiety.     

Genetic and environmental links between motor activity level and attention problems in early childhood

Cross‐lagged biometric models were used to examine genetic and environmental links between actigraph‐assessed motor activity level (AL) and parent‐rated attention problems (AP) in 314 same‐sex twin pairs (MZ = 145, DZ = 169) at ages 2 and 3 years. At both ages, genetic correlations between AL and AP were moderate (r_a2 = .35; r_a3 = .39) indicating both overlap and specificity in genetic effects across the two domains. Within‐ and across‐age phenotypic associations between AL and AP were entirely due to overlapping genetic influences. There was a unidirectional effect of AL at age 2 predicting later AP. For AP, genetic and environmental influences from age 2 were transmitted to age 3 via stability effects and from AL. For AL, across‐age effects were transmitted only via stability. These results suggest that overactivity in late infancy may impact the later development of problems related to inattention, and that genetic factors explain the association between the two domains.     

Evaluating the Etiology of Anxiety Sensitivity: Relation to Cardiovascular Perception and Reactivity

A large body of research has suggested that anxiety sensitivity (AS) acts as a specific vulnerability factor in the development of anxiety pathology. More recently, attention has turned to the etiology of AS per se. The present study tested several related etiological hypotheses derived from Expectancy theory. S. Reiss and R. J. McNally (1985) originally proposed that greater physiological reactivity would increase risk for developing heightened AS. Reactive individuals are believed to have greater opportunity to perceive unpleasant bodily perturbations, thereby increasing the likelihood that concerns and fears could be attached to the sensations. Nonclinical participants (N = 86) completed physical (e.g., orthostatic) and biological (e.g., 35% CO₂) challenges and a heart beat perception task. AS was not related to heart beat perception but was related to greater tonic heart rate and greater diastolic blood pressure (DBP) reactivity to both the challenges. Higher DBP and higher heart beat accuracy interacted to predict higher AS.     

Longitudinal development of manual motor ability in autism spectrum disorder from childhood to mid‐adulthood relates to adaptive daily living skills

Many individuals with autism spectrum disorder (ASD) exhibit motor difficulties, but it is unknown whether manual motor skills improve, plateau, or decline in ASD in the transition from childhood into adulthood. Atypical development of manual motor skills could impact the ability to learn and perform daily activities across the life span. This study examined longitudinal grip strength and finger tapping development in individuals with ASD (n = 90) compared to individuals with typical development (n = 56), ages 5 to 40 years old. We further examined manual motor performance as a possible correlate of current and future daily living skills. The group with ASD demonstrated atypical motor development, characterized by similar performance during childhood but increasingly poorer performance from adolescence into adulthood. Grip strength was correlated with current adaptive daily living skills, and Time 1 grip strength predicted daily living skills eight years into the future. These results suggest that individuals with ASD may experience increasingly more pronounced motor difficulties from adolescence into adulthood and that manual motor performance in ASD is related to adaptive daily living skills.