Procedural Memory Deficits in Preschool Children with Developmental Language Disorder in a Spanish-Speaking Population.

This study aimed to compare procedural learning skills between Spanish-speaking preschool children (ages 4 years to 4 years, 11 months) with developmental language disorder (DLD) and their chronologically matched typically developing (TD) peers. Using the serial reaction time (SRT) task, participants (30 children with DLD and 30 TD children) responded to visual stimuli in a sequenced manner over four blocks, followed by a random order block. The task assessed reaction time (RT) and accuracy. The results showed a significant interaction between group and block for RT and accuracy, with children with DLD exhibiting longer RTs and accuracy deficits across blocks. In contrast, the TD group showed higher RT efficiency and accuracy in the sequential blocks and, as expected, decreased performance in the random block according to the experimental manipulation. Overall, the results of this investigation suggest that there was no implicit learning in the DLD group, as indicated by the SRT task paradigms of procedural memory. These findings align with some aspects of the procedural deficit hypothesis (PDH), which suggests that linguistic deficits in the DLD population may derive from a deficit in sequential learning from the procedural memory system domain in the Spanish context.

Moderate-intensity cardiovascular exercise performed before motor practice attenuates offline implicit motor learning in stroke survivors but not age-matched neurotypical adults.

The acute impact of cardiovascular exercise on implicit motor learning of stroke survivors is still unknown. We investigated the effects of cardiovascular exercise on implicit motor learning of mild-moderately impaired chronic stroke survivors and neurotypical adults. We addressed whether exercise priming effects are time-dependent (e.g., exercise before or after practice) in the encoding (acquisition) and recall (retention) phases. Forty-five stroke survivors and 45 age-matched neurotypical adults were randomized into three sub-groups: BEFORE (exercise, then motor practice), AFTER (motor practice, then exercise), and No-EX (motor practice alone). All sub-groups practiced a serial reaction time task (five repeated and two pseudorandom sequences per day) on three consecutive days, followed 7 days later by a retention test (one repeated sequence). Exercise was performed on a stationary bike, (one 20-min bout per day) at 50% to 70% heart rate reserve. Implicit motor learning was measured as a difference score (repeated-pseudorandom sequence response time) during practice (acquisition) and recall (delayed retention). Separate analyses were performed on the stroke and neurotypical groups using linear mixed-effects models (participant ID was a random effect). There was no exercise-induced benefit on implicit motor learning for any sub-group. However, exercise performed before practice impaired encoding in neurotypical adults and attenuated retention performance of stroke survivors. There is no benefit to implicit motor learning of moderately intense cardiovascular exercise for stroke survivors or age-matched neurotypical adults, regardless of timing. Practice under a high arousal state and exercise-induced fatigue may have attenuated offline learning in stroke survivors.

Aprendizagem de línguas em neuropsicologia: a Teoria Declarativa/Procedural / Language learningin neuropsychology: Declarative/Procedural Theory

Este artigo objetiva oferecer uma ampla revisão do framework da Teoria Declarativa/Procedural (DPT), de Michael Ullman, a partir de artigos publicados entre 1998, quando a DPT foi proposta, até 2016. A DPT sustenta que a aprendizagem da linguagem depende de dois sistemas de memória: o léxico é aprendido por memória declarativa, e as regras gramaticais, por memória procedural. Com esta revisão, os resultados obtidos são: (a) estudos com pacientes com distúrbios, utilizando neuroimagens, verificaram as áreas encefálicas ativadas durante a realização de atividades ligadas à linguagem e à memória; (b) identificação de que as memórias declarativa e procedural não são específicas da linguagem, pois atuam em habilidades motoras e recordações de fatos e eventos; (c) com o avanço das pesquisas, a DTP tornou-se mais flexível, admitindo que os sistemas de memória, mesmo independentes, interagem de várias formas; e (d) fatores como idade, frequência de exposição ao input linguístico, disfunções e hormônios impactam no uso dos dois sistemas.

This paper aims at providing a wide review of the Michael Ullman's Declarative/Procedural Theory framework from papers published between 1998 (when DPT was proposed) and 2016. The DPTclaims that the language learning depends upon two distinct memory systems: lexicon is learned by declarative memory, whereas grammar rules use procedural memory. From this review, the results are: (a) studies with patients with disorders, using neuroimaging, revealed regions of the encephalon that were activated during the performance of activities involving language and memory; (b) identification that the declarative and procedural memories are not domain-specific, since they act on motor abilities and retrieval of facts and events; c) with the improvement of the researches, Ullman's theory became more flexible, admitting that even though the memory systems are independent, they interact many times; and variables such as age, frequency, disorders and hormonal issues impact on the use of both memory systems.

Partial lesion of dopamine neurons of rat substantia nigra impairs conditioned place aversion but spares conditioned place preference.

Midbrain dopamine neurons play critical roles in reward- and aversion-driven associative learning. However, it is not clear whether they do this by a common mechanism or by separate mechanisms that can be dissociated. In the present study we addressed this question by testing whether a partial lesion of the dopamine neurons of the rat SNc has comparable effects on conditioned place preference (CPP) learning and conditioned place aversion (CPA) learning. Partial lesions of dopamine neurons in the rat substantia nigra pars compacta (SNc) induced by bilateral intranigral infusion of 6-hydroxydopamine (6-OHDA, 3µg/side) or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 200µg/side) impaired learning of conditioned place aversion (CPA) without affecting conditioned place preference (CPP) learning. Control experiments demonstrated that these lesions did not impair motor performance and did not alter the hedonic value of the sucrose and quinine. The number of dopamine neurons in the caudal part of the SNc positively correlated with the CPP scores of the 6-OHDA rats and negatively correlated with CPA scores of the SHAM rats. In addition, the CPA scores of the 6-OHDA rats positively correlated with the tissue content of striatal dopamine. Insomuch as reward-driven learning depends on an increase in dopamine release by nigral neurons, these findings show that this mechanism is functional even in rats with a partial lesion of the SNc. On the other hand, if aversion-driven learning depends on a reduction of extracellular dopamine in the striatum, the present study suggests that this mechanism is no longer functional after the partial SNc lesion.

The roles of the nucleus accumbens core, dorsomedial striatum, and dorsolateral striatum in learning: performance and extinction of Pavlovian fear-conditioned responses and instrumental avoidance responses.

This study examined the effects of bilateral excitotoxic lesions of the nucleus accumbens core (NAc-co), dorsomedial striatum (DMS) or dorsolateral striatum (DLS) of rats on the learning and extinction of Pavlovian and instrumental components of conditioned avoidance responses (CARs). None of the lesions caused sensorimotor deficits that could affect locomotion. Lesions of the NAc-co, but not DMS or DLS, decreased unconditioned and conditioned freezing. The NAc-co and DLS lesioned rats learned the 2-way active avoidance task more slowly. These results suggest: (i) CARs depend on both Pavlovian and instrumental learning; (ii) learning the Pavlovian component of CARs depends on the NAc-co; learning the instrumental component of CARs depends on the DLS, NAc and DMS; (iii) although the NAc-co is also needed for learning the instrumental component, it is not clear whether it plays a role in learning the instrumental component per se or if it simply allows learning of the Pavlovian component which is a pre-condition for learning the instrumental component; (iv) we did not find evidence that the DMS and DLS play the same roles in habit and goal-directed aspects of the instrumental component of CARs as observed in appetitive motivated instrumental responding.

Memoria de trabajo y memoria procedimental en las dificultades específicas del aprendizaje y del lenguaje: algunos hallazgos / Working memory and procedural memory in Specific Learning and Language Difficulties: some findings

Este artículo describe las relaciones entre los déficit de memoria de trabajo y de memoria procedimental con las dificultades específicas de aprendizaje y el trastorno específico del lenguaje. La memoria de trabajo es un sistema que comprende varios componentes cuya actividad coordinada proporciona la capacidad para el almacenamiento temporal y la manipulación de la información en una variedad de dominios. La memoria procedimental de largo plazo es un sistema particularmente importante para la adquisición y ejecución de habilidades que involucran secuencias de diferentes tipos (motoras y cognitivas). Los trastornos específicos del lenguaje y dificultades específicas del aprendizaje están estrechamente asociados con déficit selectivos en los dos sistemas de memoria. Se comentan las implicaciones de estos hallazgos para la práctica educativa y la rehabilitación.

This paper describes the relationships between working and procedural memory deficits with specific learning disabilities and specific language impairment. Working memory is a system comprising multiple components whose coordinated activity provides the capacity for the temporary storage and manipulation of information in a variety of domains. Long term procedural memory is a system particularly important for acquiring and performing skills involving sequences of different types (motor and cognitive). Specific language impairments and specific learning disabilities are closely associated to selective deficits in both memory systems. The implications of these findings for educational practice and rehabilitation are considered.