Cerebellar dentate nuclei lesions reduce motivation in appetitive operant conditioning and open field exploration

Recently identified pathways from the dentate nuclei of the cerebellum to the rostral cerebral cortex via the thalamus suggest a cerebellar role in frontal and prefrontal non-motor functioning. Disturbance of cerebellar morphology and connectivity, particularly involving these cerebellothalamocortical (CTC) projections, has been implicated in motivational and cognitive deficits. The current study explored the effects of CTC disruption on motivation in male Long Evans rats. The results of two experiments demonstrate that electrolytic lesions of the cerebellar dentate nuclei lower breaking points on an operant conditioning progressive ratio schedule and decrease open field exploration compared to sham controls. Changes occurred in the absence of motor impairment, assessed via lever pressing frequency and rotarod performance. Similar elevated plus maze performances between lesioned and sham animals indicated that anxiety did not influence task performance. Our results demonstrate hedonic and purposive motivational reduction and suggest a CTC role in global motivational processes. These implications are discussed in terms of psychiatric disorders such as schizophrenia and autism, in which cerebellar damage and motivational deficits often present concomitantly.     

Only self-generated actions create sensori-motor systems in the developing brain

Previous research shows that sensory and motor systems interact during perception, but how these connections among systems are created during development is unknown. The current work exposes young children to novel 'verbs' and objects through either (a) actively exploring the objects or (b) by seeing an experimenter interact with the objects. Results demonstrate that the motor system is recruited during auditory perception only after learning involved self-generated interactions with objects. Action observation itself led to above-baseline activation in one motor region during visual perception, but was still significantly less active than after self-generated action. Therefore, in the developing brain, associations are built upon real-world interactions of body and environment, leading to sensori-motor representations of both objects and words.     

Essential neuronal pathways for reflex and conditioned response initiation in an intracerebellar stimulation paradigm and the impact of unconditioned stimulus preexposure on learning rate

It has been demonstrated previously that pairing of tone CS and intracerebellar stimulation of lobule HVI white matter as the US produces conditioning that is robust and in many ways similar to that obtained with an airpuff US. The first study in this report addressed the effect of interpositus lesions on conditioned performance in rabbits trained with white matter stimulation as the US. It was found that interpositus lesions effectively eliminated the CR irrespective of the behavioral response measured. In addition, it was shown that the interpositus lesions also abolished the UR, providing strong evidence that the effects of the electrical stimulation were confined to the cerebellum and did not require the activation of brainstem structures. The second experiment examined performance on US-alone trials of varying durations. Response initiation within 100 ms of the US onset, regardless of US duration, indicated that reflex generation could not be due to rebound excitation of the interpositus following termination of Purkinje cell inhibition of that structure but instead likely reflects orthodromic activation of interpositus neurons via climbing fiber and/or mossy fiber collaterals. The impact of US preexposure on associative conditioning in this paradigm was also determined. Animals which received only 108 US-alone trials were massively impaired during subsequent training compared to rabbits that received fewer than 12 US-alone trials.     

Object‐based visual processing in children with spina bifida and hydrocephalus: A cognitive neuropsychological analysis

The aim of the study was to use cognitive neuropsychological analysis to investigate object‐based visual processing skills in children with spina bifida myelomeningocele and hydrocephalus (SBH). Fourteen children with SBH (aged 8–12) and 21 age‐, socio‐economic status‐, and Verbal IQ‐matched healthy controls were assessed using the Birmingham Object Recognition Battery. Overall, the performance of the children with SBH on the object‐processing tasks was intact, indicating normal development of the ventral visual processing pathway. While the initial results indicated that the children with SBH performed statistically significantly less accurately on some tasks, these group differences no longer met significance criteria after capacity for sustained attention was statistically controlled.     

Creatine supplementation and cognitive performance in elderly individuals

The purpose of this study was to examine the effect of creatine supplementation on the cognitive performance of elderly people. Participants were divided into two groups, which were tested on random number generation, forward and backward number and spatial recall, and long-term memory tasks to establish a baseline level. Group 1 (n = 15) were given 5 g four times a day of placebo for 1 week, followed by the same dosage of creatine for the second week. Group 2 (n = 17) were given placebo both weeks. Participants were retested at the end of each week. Results showed a significant effect of creatine supplementation on all tasks except backward number recall. It was concluded that creatine supplementation aids cognition in the elderly.     

The Obedience of the Eternal Son

According to Karl Barth, the obedience of the eternal Son in the economy of salvation is the proper mode whereby he enacts the undivided work of the Trinity ‘for us and our salvation’. This thesis now enjoys rather wide acceptance among contemporary theologians. In many instances, adopting this viewpoint has resulted in significant revisions of traditional trinitarian metaphysics. The purpose of the present article is to demonstrate that adopting Barth's thesis does not require such revision and that this thesis can and should be appropriated within the orbit of traditional trinitarian theology. We will endeavor to establish our claim by considering the relationship between the Son's eternal generation and his economic obedience, and by addressing three major objections that might be raised against our claim.     

Incremental exercise, plasma concentrations of catecholamines, reaction time, and motor time during performance of a noncompatible choice response time task

The primary purpose was to examine the effect of incremental exercise on a noncompatible response time task. Participants (N=9) undertook a 4-choice noncompatible response time task under 3 conditions, following rest and during exercise at 70% and 100% of their maximum power output. Reaction and movement times were the dependent variables. Maximum power output had been previously established on an incremental test to exhaustion. A repeated-measures multivariate analysis of variance yielded a significant effect of exercise intensity on the task, observation of the separate univariate repeated-measures analyses of variance showed that only movement time was significantly affected. Post hoc Tukey tests indicated movement time during maximal intensity exercise was significantly faster than in the other two conditions. The secondary purpose of the study was to assess whether increases in plasma concentrations of adrenaline and nor-adrenaline during exercise and power output would act as predictor variables of reaction and movement times during exercise. Catecholamine concentrations were based on venous blood samples taken during the maximum power output test. None of the variables were significant predictors of reaction time. Only power output was a significant predictor of movement time (R2 = .24). There was little support for the notion that peripheral concentrations of catecholamines directly induce a central nervous system response.     

Selective Synaptic Plasticity within the Cerebellar Cortex Following Complex Motor Skill Learning

Complex motor skill learning, but not mere motor activity, leads to an increase in synapse number within the cerebellar cortex. The present experiment used quantitative electron microscopy to determine which synapse types were altered in number. Adult female rats were allocated to either an acrobatic condition (AC), a voluntary exercise condition (VX), or an inactive condition (IC). AC animals were trained to traverse an elevated obstacle course requiring substantial motor coordination to complete. VX animals were housed with unlimited access to running wheels and IC animals received no motor training but were handled briefly each day. Results showed the AC animals to have significantly more parallel fiber to Purkinje cell synapses than both the VX and IC animals. No other synapse type was significantly altered. Thus, the learning-dependent increase in synapse number observed within the cerebellar cortex is accomplished primarily through the addition of parallel fiber synapses.     

The G-NORM Scale: Development and Validation of a Theory-Based Gender Norms Scale

Sex Roles - Gender norms are increasingly recognized as important modifiers of health. Despite growing awareness of how gender norms affect health behavior, current gender norms scales are often...