Hand differences in aiming task: a complementary spatial approach and analysis ofdynamic brain networks with EEG.

Left and right-hand exhibit differences in the execution of movements. Particularly, it has been shown that manual goal-directed aiming is more accurate with the right hand than with the left, which has been explained through the shorter time spent by the right hand in the feedback phase (FB). This explanation makes sense for the temporal aspects of the task; however, there is a lack of explanations for the spatial aspects. The present study hypothesizes that the right hand is more associated with the FB, while the left hand is more strongly associated with the pre-programming phase (PP). In addition, the present study aims to investigate differences between hands in functional brain connectivity (FBC). We hypothesize an increase in FBC of the right hand compared to the left hand. Twenty-two participants performed 20 trials of the goal-directed aiming task with both hands. Overall, the results confirm the study's hypotheses. Although the right hand stopped far from the target at the PP, it exhibited a lower final position error than the left hand. These findings imply that during the FB, the right hand compensates for the higher error observed in the PP, using the visual feedback to approach the target more closely than the left hand. Conversely, the left hand displayed a lower error at the PP than the right. Also, the right hand displayed greater FBC within and between brain hemispheres. This heightened connectivity in the right hand might be associated with inhibitory mechanisms between hemispheres.

Executive Functions and Motor Adaptation to Predictable and Unpredictable Perturbations.

In this study, we aimed to investigate the influence of executive functions (EF) on motor adaptation. We compared the motor performance of adults with and without EF deficits. Those with EF deficits (n = 21) were individuals with attention deficit hyperactivity disorder (ADHD) under medical treatment, and those without EF deficits (n = 21) comprised a control group (CG) of participants who were also without neurological or psychiatric diagnoses. Both groups performed a complex coincident timing motor task and various computerized neuropsychological tests for assessing EF. To investigate motor adaptation, the motor task provided measures of absolute error (AE) and variable error (VE) to reflect, respectively, performance accuracy and consistency relative to the task goal. We used reaction time (RT) to measure planning time taken before starting the task. First, participants practiced until they reached a criterion of performance stabilization (prior to their exposure to motor perturbations). They were next exposed to fast and slow predictable and unpredictable perturbations. On all neuropsychological tasks, participants with ADHD scored more poorly than control participants (p < .05); participants with ADHD also performed worse than control participants on all motor measures, particularly under unpredictable perturbations (p < .05). Under slow perturbations, EF deficits, particularly attentional impulsivity, negatively affected motor adaptation while cognitive flexibility was related to performance improvement. Under fast perturbations, both impulsivity and fast reaction time were related to improvement in motor adaptation under both predictable and unpredictable perturbations. We discuss the research and practical implications of these findings.

Motor learning and tDCS: A systematic review on the dependency of the stimulation effect on motor task characteristics or tDCS assembly specifications.

TDCS is one of the most commonly used methods among studies with transcranial electrical stimulation and motor skills learning. Differences between study results suggest that the effect of tDCS on motor learning is dependent on the motor task performed or on the tDCS assembly specification used in the learning process. This systematic review aimed to analyze the tDCS effect on motor learning and verify whether this effect is dependent on the task or tDCS assembly specifications. Searches were performed in PubMed, SciELO, LILACS, Web of Science, CINAHL, Scopus, SPORTDiscus, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and PsycINFO. Articles were included that analyzed the effect of tDCS on motor learning through pre-practice, post-practice, retention, and/or transfer tests (period ≥24 h). The tDCS was most frequently applied to the primary motor cortex (M1) or the cerebellar cortex (CC) and the majority of studies found significant stimulation effects. Studies that analyzed identical or similar motor tasks show divergent results for the tDCS effect, even when the assembly specifications are the same. The tDCS effect is not dependent on motor task characteristics or tDCS assembly specifications alone but is dependent on the interaction between these factors. This interaction occurs between uni and bimanual tasks with anodal uni and bihemispheric (bilateral) stimulations at M1 or with anodal unihemispheric stimulations (unilateral and centrally) at CC, and between tasks of greater or lesser difficulty with single or multiple tDCS sessions. Movement time seems to be more sensitive than errors to indicate the effects of tDCS on motor learning, and a sufficient amount of motor practice to reach the "learning plateau" also seems to determine the effect of tDCS on motor learning.

Working Memory and Manual Dexterity in Dyslexic Children: A Systematic Review and Meta-Analysis.

Dyslexic children have impairments in working memory and manual dexterity. Studies have shown that when cognitive development has deficits, motor development is often impaired, indicating a strong interconnection between both domains, and the possibility of interference with each other's proper functioning. Thus, a new literature review is necessary to understand which components of working memory and manual dexterity are affected in dyslexic children and the possible relationship between them. This review aimed to perform a systematic review and meta-analysis to analyze both skills in dyslexic children. The protocol was carried out according to the criteria established by PRISMA being registered at PROSPERO under number CRD 42021238901. Six literature databases were searched to locate studies published between 2001 and 2021: EMBASE, ERIC, ISI Web of Science, PubMed, PsycINFO, and Scopus. 21 studies met the inclusion criteria. The findings suggest that dyslexic children have significantly poorer visuospatial and verbal working memory with more impairments in the phonological loop. No significant differences were found in manual dexterity.

The Effect of Different Combinations of Practice Schedules on Motor Response Stability during Practice.

Many results in motor learning have indicated that relative and absolute timing dimensions are modulated by factors that modify response stability among trials. One of these factors is the combination of constant and variable practices. Although many researchers have investigated the combination of practice schedules, these researchers have used measurements that do not assess performance and motor response separately. This study aimed to investigate the effect of different combinations of practice schedules on motor response stability during practice. Participants performed a sequential key-pressing task with two goals: (1) to learn the relative timing dimension and (2) the absolute timing dimension. Participants were assigned to one of two groups: constant-variable or variable-constant. Our findings indicate an influence of the increase in variability over the practice in the constant-variable group. Precisely, the increase in variability of total time in the second half (constant-variable group) of practice was followed by the maintenance of the same level of cross-correlate between absolute timing error and variability of total time. Finally, our findings support the hypothesis that practicing in a constant schedule favors the relative timing dimension of learning regardless of the order in which the constant practice is provided.

Association Between Cross-Limb Transfer and Practice Organization.

Although the importance of practice has been evidenced in early studies of cross-limb transfer, the association between cross-limb transfer and practice organization remains unknown. The two primary means of organizing practice are constant practice (CP) and variable practice (VP). When the same generalized motor program governs the motor responses, VP produces better transfer than CP. Thus, we hypothesized that VP would generate a higher cross-limb transfer level than CP. We assigned 40 participants to CP or VP groups and conducted an experiment consisting of three phases: pre-test, practice, and transfer test. At pre-test, all participants practiced eight trials of a sequence key-pressing task with the non-dominant hand (NDH). After the pre-test, all participants performed a practice phase of 72 trials with the dominant hand, but CP and VP groups underwent their different practice schedules (CP or VP) such that the CP group practiced a sequence key-pressing task in one sequence, and the VP group practiced four different sequences randomly. On the transfer test all partcipants completed eight trials with the NDH 24 hours after the practice phase. The CP group showed better performance than the VP group on the transfer test, and we concluded that the effects of practice organization in cross-limb transfer are distinct from intra- and inter-task transfer such that the specificity of practice explained the benefits of CG.

O conhecimento do professor de educação física sobre aprendizagem motora / O conhecimento do professor de educação física sobre aprendizagem motora / El conocimiento del profesor de educación física sobre el aprendizaje motor

O objetivo deste estudo foi investigar o nível de conhecimento de graduados e graduandos em Educação Física sobre Aprendizagem Motora. Para isso, foi elaborado um questionário com 20 questões, sendo a primeira parte relacionada à identificação dos participantes e a segunda relacionada à Aprendizagem Motora. A análise foi feita com base na frequência de respostas dos participantes. A maioria dos participantes afirmou que sabiam o que era Aprendizagem Motora. No entanto, exibiram dificuldades em relação a algumas informações sobre a parte teórica. Além disso, os participantes apresentaram dificuldade em responder questões relacionadas aos fatores que influenciam a aprendizagem motora. Apesar do conhecimento sobre a temática contribuir efetivamente na forma pela qual o professor de educação física planeja e conduz as suas aulas, os participantes apresentaram impasses em responder às questões (AU).

The study aimed to investigate the level of knowledge of undergraduate and graduate students in physical education on Motor Learning. For this, a questionnaire with 20 questions was elaborated, the first part related to the identification of the participants and the second related to Motor Learning. The analysis was made based on the frequency of responses from the participants. Most of the participants stated that they knew what Motor Learning was. However, they showed difficulties about some information about the theoretical part. Also, the participants had difficulty in answering questions related to the factors that influence motor learning. Despite the knowledge about the theme effectively contributing to the way the physical education teacher plans and conducts his classes, the participants presented impasses in answering the questions (AU).

El objetivo del estudio fue investigar el nivel de conocimiento de estudiantes de pregrado y posgrado en educación física sobre el aprendizaje motor. Para esto, se elaboró un cuestionario con 20 preguntas, la primera parte relacionada con la identificación de los participantes y la segunda relacionada con el aprendizaje motor. El análisis se realizó en función de la frecuencia de las respuestas de los participantes. La mayoría de los participantes declararon que sabían lo que era el aprendizaje motor. Sin embargo, mostraron dificultades en relación con alguna información sobre la parte teórica. Además, los participantes tuvieron dificultades para responder preguntas relacionadas con los factores que influyen en el aprendizaje motor. A pesar de que el conocimiento sobre el tema contribuyó efectivamente a la forma en que el maestro de educación física planifica y dirige sus clases, los participantes presentaron dificultades para responder las preguntas (AU).

Mirror therapy in upper limb motor recovery and activities of daily living, and its neural correlates in stroke individuals: A systematic review and meta-analysis.

Available literature indicates that 30-66% of stroke survivors present persistent upper limb impairment. Considering the importance of upper limb function for activities of daily living, it is necessary to investigate neurorehabilitation therapies that could improve the upper limb function. Among stroke complementary therapies, mirror therapy has shown promising results. Thus, the aim of this systematic review and meta-analyses was to review and synthesize clinical evidence on the use of mirror therapy on motor recovery of the upper limb and activities of daily living, and its neural correlates in stroke patients. The literature search was carried out in PubMed, ISI Web of Science, and Scopus databases. Twenty-nine studies met all the inclusion criteria. Two meta-analyses were conducted to compare mirror therapy with sham therapy on two general measures, upper limb assessment and activities of daily living. Results suggest that mirror therapy was better than sham therapy, mainly in the subacute phase, but the meta-analyses were nonsignificant. In addition, mirror therapy and cortical reorganization showed potential neural correlates, such as the primary motor cortex, precuneus, and posterior cingulate cortex.

No Effects of Mental Fatigue and Cerebral Stimulation on Physical Performance of Master Swimmers.

Background: Mental fatigue is a psychobiological state caused by extended periods of cognitive effort, and evidence suggests that mentally fatigued athletes present impaired physical performance. Different ergogenic aids have been proposed to counteract the deleterious effects of mental fatigue, but whether brain stimulation can counteract mental fatigue is still unknown. This scenario is even more obscure considering the effects of these interventions (mental fatigue induction and brain stimulation) in a very experienced population consisting of master athletes. Method: Ten master swimmers (30 ± 6 years old and 14 ± 8 years of experience) participated in the study. They underwent four experimental conditions before an 800-m freestyle test: mental fatigue with brain stimulation; mental fatigue without brain stimulation; absence of mental fatigue with brain stimulation; and absence of mental fatigue and no brain stimulation. Mental fatigue was induced by a cognitively demanding Stroop Color Test, whereas stimulation was applied on the temporal cortex. After that, the athletes swan 800 m as fast as possible and provided their ratings of perceived exertion (RPE) every 200 m. Results: Mental fatigue was effectively induced, as evidenced by a greater fatigue perception and more errors in the last blocks of the cognitive task. Mental fatigue induction did not influence performance (time to complete the swimming trial) and RPE. Similarly, brain stimulation failed to change these two parameters, regardless of mental fatigue induction. Conclusion: The prolonged physical performance of experienced master athletes is not influenced, under the present conditions, by mental fatigue induction, cerebral stimulation, and their association.

Influence of Chronotype on Motor Behavior in Healthy Individuals: Analyses of Manual Dexterity in Different Times of the Day.

This study investigated the influence of chronotype on motor behavior in a manual dexterity task performed at different times of the day. Sixteen healthy adults of each chronotype (morning, evening, and neither), as measured by the Morningness-Eveningness Questionnaire, practiced both conditions of the Grooved Pegboard Test either in the morning or in the afternoon to early evening. The "neither" chronotype (65.12 ± 7.46) was outperformed (ps ≤ .03) by both the morning (56.09 ± 7.21) and evening (58.94 ± 7.53) chronotypes when the task had higher cognitive and motor demand but was not outperformed in the task with lower demand (morning = 18.46 ± 2.11; evening = 19.34 ± 2.79; neither = 21.47 ± 2.54; p > .05). No difference between the morning and evening chronotypes was found at the different times of the day (ps > .05), suggesting that a manual dexterity task is not sufficiently demanding to be influenced by chronotype.

Caffeine Produces Neutral Effects on Extraverts' and Introverts' Performance of Fundamental Motor Skills.

Extraverts are active and talkative, while introverts are quiet and calm. This difference has been attributed to the cortical activation level (arousal), which is low in extraverts and high in introverts. Thus, to reach an optimal level of arousal, extraverts seek stimulation and introverts avoid it. As caffeine increases arousal levels, our primary aim was to investigate the effect of caffeine on the performance of extraverted and introverted university students in the execution of stability, manipulative, and locomotor tasks. Considering the above, we evaluated side effects, such as restlessness and trembling of hands, we also analyzed the individual's perception regarding caffeine intake and the placebo. Forty two volunteers were classified as 21 extraverts and 21 introverts by the Eysenck Personality Questionnaire. Participants performed three tasks on two different days, having previously ingested caffeine and a placebo in counterbalanced order. A double-blind technique was employed. The dependent variable was the execution time to perform the tasks. The analyses of variance [2 (extraversion/introversion) x 2 (caffeine x placebo)] for each task did not show significant differences. Regarding the secondary aim, the chi-square test showed that introverts had a better perception of the substance they had ingested than did extraverts. Our findings indicate that in the execution of stability, manipulative, and locomotor tasks, either caffeine or the placebo produced the same effect, regardless of the participants' extraversion score. In addition, introverts were more sensitive to perceive which substance was ingested, caffeine or the placebo, than extraverts.

The effect of context variability on motor learning.

Although the practice schedule and variation in incidental context have been investigated together, it is not clear whether just variation in incidental context can beneficiate motor learning. Therefore, the present study aimed to investigate the effect of context variability on motor learning. We hypothesized the practice in a variable incidental context would enable learners to be more resistant to the effects of the contextual changes when compared to a constant incidental context practice. Twenty-four participants were assigned to one of the two groups: constant incidental context (G_CC) or variable incidental context (G_VC). During practice, the G_CC practiced a sequence keypressing task in one color and a position showed on the computer screen. The G_VC practiced the same sequence in four different combinations of color and position. Twenty four hours, the same contexts practiced on practice (SAME) was performed and immediately after, a new sequential movement in new color and new position (SWITCH) was performed. The results indicated that the G_VC showed better performance than the G_CC on the SWITCH condition, mainly in measures related to planning/selection process. The results were explained by degree of similarity among processing events engaged during different moments and by development of a filter of information based on attentional selection.

Individual Responses to Different Vibration Frequencies Identified by Electromyography and Dynamometry in Different Types of Vibration Application.

ABSTRACT: Oliveira, MP, Menzel, H-JK, Cochrane, DJ, Drummond, MD, Demicheli, C, Lage, G, and Couto, BP. Individual responses to different vibration frequencies identified by electromyography and dynamometry in different types of vibration application. J Strength Cond Res 35(6): 1748-1759, 2021-The application of mechanical vibration is a common neuromuscular training technique used in sports training programs to generate acute increases in muscle strength. The principal aim of the study was to compare the individual optimal vibration frequency (IOVF) identified by electromyography (EMG) activity and force production in strength training. Twenty well-trained male volunteers (age: 23.8 ± 3.3 years) performed a familiarization and 2 interventions sessions, which included 5 maximal voluntary contractions (MVCs) of the elbow flexors with a duration of 10 seconds and 5-minute intervals between each MVC. The first MVC was performed without vibration followed by 4 randomized MVCs with application of vibration in the direction of the resultant muscle forces' vector (VDF) or whole-body vibration (WBV) at frequencies of 10, 20, 30, or 40 Hz. The mechanical vibration stimulus was superimposed during the MVC. Individual optimal vibration frequency, as identified by EMG, did not coincide with IOVF identified by force production; low agreement was observed between the vibration frequencies in generating the higher EMG activity, maximal force, and root mean square of force. These findings suggest that the magnitude of the vibratory stimulus response is individualized. Therefore, if the aim is to use acute vibration in conjunction with strength training, a preliminary vibration exposure should be conducted to determine the individualized vibratory stimulus of the subject, so that training effects can be optimized.

TDCS of the Primary Motor Cortex: Learning the Absolute Dimension of a Complex Motor Task.

The primary motor cortex (M1) is one of the main cortical areas involved in motor learning. However, little is known about its differential role in the learning of the relative and absolute dimensions of motor skills. We investigated the role of M1 in the learning of the dimensions of a complex motor skill. Forty-eight participants practiced golf putting and were stimulated for 20 minutes with real or sham bihemispheric tDCS before acquisition. tDCS improved global performance from pre- to post-test. Only those with worse initial performance who were stimulated by tDCS showed a significant improvement in the skill's absolute dimension. No effects of tDCS were found for the relative dimension. Our results suggest that M1 has a distinct participation in the learning of the absolute dimension of complex motor skills, and tDCS effects are influenced by the learner's level of initial performance.

Mental practice is associated with learning the relative timing dimension of a task.

Learning about the relative timing dimension of a motor skill is enhanced by factors that promote higher response stability between trials. Conversely, learning the absolute timing dimension is favored by lower trial-to-trial stability. The mental practice may increase response stability during acquisition since there is a low possibility of adjustments made between trials. Thus, this study aimed to test the hypothesis that some factors that increase response stability during the acquisition phase contribute to an enhanced relative timing dimension learning. Our hypothesis is that mental practice shows less relative timing error than the absence of practice. A sequential key-pressing task was practiced with two goals: learn (1) relative timing dimension and (2) absolute timing dimension. Participants were assigned to one of three groups: Physical, Mental, or No practice. The Physical group showed greater learning of both dimensions than the other two groups. The Mental group showed greater learning of relative timing dimension than the No practice group. The results suggest that mental practice produces increased stability, which in turn promotes learning of the relative timing dimension.

Análise da Lateralidade e Destreza Manual em Crianças com Transtorno do Espectro Autista / Analysis of Laterality and Manual Dexterity in Children with Autistic Spectrum Disorder

RESUMO: Este estudo teve como objetivo analisar a lateralidade e a destreza manual em crianças com Transtorno do Espectro Autista (TEA). Do ponto de vista da motricidade humana, a lateralidade contribui para o processo de maturação motora. Figura-se entre as principais características do autismo o atraso nas habilidades motoras grossas e finas, com piora progressiva no quadro. Analisar o nível de lateralidade do indivíduo com TEA torna-se importante por possibilitar uma direção na intervenção motora com o intuito de melhorar a funcionalidade do autista e sua qualidade de vida. A amostra deste estudo foi composta por oito crianças, alunos de uma instituição de ensino pública, do sexo masculino, com idade média de 8,75±1,83 anos e diagnosticadas com TEA com base no DSM-V. Os resultados mostraram que os participantes do estudo parecem apresentar lateralidade destra e, também, melhor desempenho com a mão preferida em uma tarefa de destreza manual. Observou-se que, na tarefa que exigiu maior atenção e destreza, a diferença no desempenho das mãos foi significativa. Já na tarefa com menor demanda atencional e de destreza manual, o desempenho entre as mãos não foi significante, porém foi nesse momento que foram observados os maiores erros na execução. A motivação pode ser uma variável fundamental para o desempenho motor em tarefas que avaliam o tempo de execução. É importante uma maior ênfase no desenvolvimento da motricidade desses indivíduos durante a fase escolar para diminuir as dificuldades motoras e, consequentemente, melhorar a qualidade de vida, sensação de bem-estar, autonomia e interação social.

ABSTRACT: This study aimed to analyze laterality and manual dexterity in children with Autism Spectrum Disorder (ASD). From the point of view of human motor skills, laterality contributes to the motor maturation process. Among the main characteristics of autism is the delay in gross and fine motor skills, with progressive worsening in the condition. Analyzing the level of laterality of the individual with ASD becomes important because it allows a direction in the motor intervention in order to improve the functionality and quality of life of the autistic person. The sample of this study was composed of eight children, students of a public education institution, male, with an average age of 8.75 ± 1.83 years old and diagnosed with ASD based on the DSM-V. The results showed that the study participants seem to have right handedness and also better performance with the preferred hand in a manual dexterity task. It was observed that, in the task that demanded more attention and dexterity, the difference in hand performance was significant. In the task with the lowest attentional demand and manual dexterity, the performance between the hands was not significant; however, it was at that moment that the biggest mistakes in execution were observed. Motivation can be a fundamental variable for motor performance in tasks that assess execution time. It is important to emphasize the development of the motor skills of these individuals during the school phase to reduce motor difficulties and, consequently, improve quality of life, sense of well-being, autonomy and social interaction.

Transcranial Direct Current Stimulation: No Effect on Aerobic Performance, Heart Rate, or Rating of Perceived Exertion in a Progressive Taekwondo-Specific Test.

PURPOSE: To investigate the effects of anodal transcranial direct current stimulation (a-tDCS) on the aerobic performance, heart rate (HR), and rating of perceived exertion (RPE) of highly trained taekwondo athletes. METHODS: Twelve (8 men and 4 women) international/national-level athletes received a-tDCS or sham treatment over the M1 location in a randomized, single-blind crossover design. The stimulation was delivered at 1.5 mA for 15 min using an extracephalic bihemispheric montage. Athletes performed the progressive-specific taekwondo test 10 min after stimulation. HR was monitored continuously during the test, and RPE was registered at the end of each stage and at test cessation. RESULTS: There were no significant differences between sham and a-tDCS in time to exhaustion (14.6 and 14.9, respectively, P = .53, effect size = 0.15) and peak kicking frequency (52 and 53.6, respectively, P = .53, effect size = 0.15) or in HR (P > .05) and RPE responses (P > .05). CONCLUSIONS: Extracephalic bihemispheric a-tDCS over M1 did not influence the aerobic performance of taekwondo athletes or their psychophysiological responses, so athletes and staff should be cautious when using it in a direct-to-consumer manner.

Motor learning and COMT Val158met polymorphism: Analyses of oculomotor behavior and corticocortical communication.

Differences in motor learning can be partially explained by differences in genotype. The catechol-O-methyltransferase (COMT) Val158Met polymorphism regulates the dopamine (DA) availability in the prefrontal cortex modulating motor learning and performance. Given the differences in tonic and phasic DA transmission, this study aimed to investigate whether the greater cognitive flexibility associated with the Val allele would favor the learning of movement parametrization, while the greater cognitive stability associated with the Met allele favors the acquisition of the movement pattern. Furthermore, we investigated if the genotypic characteristics impact visual scanning of information related to parametrization and to the movement pattern, and the level of cortical connectivity associated with motor planning and control. Performance and learning of a sequential motor task were compared among three genotypes (Val/Val, Val/Met, and Met/Met), as well as their oculomotor behavior and level of cortical coherence. The findings show that the cognitive flexibility promoted by the Val allele is associated with a better parametrization. The search for information through visual scanning was specific to each genotype. Also, a greater cortical connectivity associated with the Val allele was found. The combined study of behavioral, electrophysiological and molecular levels of analysis showed that the cognitive stability and flexibility associated with the COMT alleles, influence specific aspects of motor learning.

Molecular Mechanisms Associated with the Benefits of Variable Practice in Motor Learning.

Variable practice promotes a higher level of motor learning than constant practice. The glutamate receptors, n-methyl-d-aspartate (NMDA) and alfa-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA), have been associated with the changes in motor cortex that occur throughout the process of motor learning. Considering that, it is possible that variable practice is more associated with the NMDA and AMPA receptors than constant practice. This study aimed ao investigating the association between the glutamate receptors, NMDA and AMPA, and constant and variable practice schedules. Seventy-eight male mice practiced the rotarod task in a constant or variable scheduling, in two consecutive days (acquisition phase). Learning tests were performed 24 h and 10 days after the end of the acquisition phase. Variable practice was more associated with the NMDA receptor and had a greater AMPA receptor expression than constant practice. The results suggest that the benefits of variable practice are result of both the greater dependency on the NMDA receptor and the greater AMPA receptor expression.