Variations in response control within at-risk gamblers and non-gambling controls explained by GABAergic inhibition in the motor cortex

Cortex ◽  
2018 ◽  
Vol 103 ◽  
pp. 153-163 ◽  
Author(s):  
Nahian S. Chowdhury ◽  
Evan J. Livesey ◽  
Alex Blaszczynski ◽  
Justin A. Harris
Keyword(s):  
At Risk ◽  
Motor Cortex ◽  
Gabaergic Inhibition ◽  
Response Control

scholarly journals Competition, Conflict and Change of Mind: A Role of GABAergic Inhibition in the Primary Motor Cortex

2022 ◽  
Vol 15 ◽  
Author(s):  
Bastien Ribot ◽  
Aymar de Rugy ◽  
Nicolas Langbour ◽  
Anne Duron ◽  
Michel Goillandeau ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Silent Period ◽  
Single Pulse ◽  
Electromyographic Activity ◽  
Continuous Control ◽  
Gabaergic Inhibition ◽  
Inhibitory Mechanisms ◽  
Post Onset

Deciding between different voluntary movements implies a continuous control of the competition between potential actions. Many theories postulate a leading role of prefrontal cortices in this executive function, but strong evidence exists that a motor region like the primary motor cortex (M1) is also involved, possibly via inhibitory mechanisms. This was already shown during the pre-movement decision period, but not after movement onset. For this pilot experiment we designed a new task compatible with the dynamics of post-onset control to study the silent period (SP) duration, a pause in electromyographic activity after single-pulse transcranial magnetic stimulation that reflects inhibitory mechanisms. A careful analysis of the SP during the ongoing movement indicates a gradual increase in inhibitory mechanisms with the level of competition, consistent with an increase in mutual inhibition between alternative movement options. However, we also observed a decreased SP duration for high-competition trials associated with change-of-mind inflections in their trajectories. Our results suggest a new post-onset adaptive process that consists in a transient reduction of GABAergic inhibition within M1 for highly conflicting situations. We propose that this reduced inhibition softens the competition between concurrent motor options, thereby favoring response vacillation, an adaptive strategy that proved successful at improving behavioral performance.

GABAergic inhibition of neuronal activity in the primate motor and premotor cortex during voluntary movement

1992 ◽  
Vol 68 (3) ◽  
pp. 692-702 ◽  
Author(s):  
M. Matsumura ◽  
T. Sawaguchi ◽  
K. Kubota
Keyword(s):  
Motor Cortex ◽  
Neuronal Activity ◽  
Cortical Neurons ◽  
Voluntary Movement ◽  
Lever Press ◽  
Premotor Cortex ◽  
Gabaergic Inhibition ◽  
Gamma Aminobutyric Acid ◽  
Single Neurons ◽  
Lever Release

1. The functional role of GABAergic inhibition in neuronal activity in the forearm-hand area of the motor cortex and the postarcuate premotor cortex was studied while monkeys pressed and released a lever in response to a visual cue. gamma-Aminobutyric acid (GABA), its agonist muscimol (MUS), and its antagonist bicuculline methiodide (BMI), as well as acetylcholine, noradrenaline, and sodium glutamate, were applied iontophoretically to isolated single neurons whose activity was recorded via glass micropipettes that contained carbon fibers. 2. The activity from single neurons recorded in the motor and premotor cortex showed changes during the press or release of the lever by movement of the contralateral wrist. Discharge of most of the movement-related neurons (greater than 90%) was decreased or completely suppressed by iontophoretically applied GABA or MUS. 3. The activity of the movement-related neurons increased after application of BMI. In 70% of neurons tested, the activity during application of BMI was specifically enhanced at or near the phase of their peaks of activity, with or without a noticeable elevation in background activity. 4. About 10% of the neurons that had been unidirectional (i.e., neurons that showed a change in activity at either the lever-press or lever-release phase) became bidirectional (i.e., they showed changes in activity at both phases) when GABA transmission was blocked by the application of BMI. Bidirectional neurons also showed a reduction in the value of the directionality index. 5. One-half of the silent neurons, which had not shown any activity during either the lever-release or the lever-press phase, became active during the movement phases that followed application of BMI. 6. Most of the cortical neurons in layers II-VI in the motor area were found to be subject to GABAergic inhibition during voluntary movement. 7. We conclude that GABAergic inhibition plays a role in regulating the population of task-related neurons, and the levels of the task-related activity. GABAergic inhibition also improves directionality index in the motor cortex neurons to control the activity of target muscles.

Phonological Awareness Screening to Identify At-Risk Readers

1998 ◽  
Vol 29 (2) ◽  
pp. 109-116 ◽  
Author(s):  
Margie Gilbertson ◽  
Ronald K. Bramlett
Keyword(s):  
At Risk ◽  
Phonological Awareness ◽  
Reading Ability ◽  
At Risk Students ◽  
First Grade ◽  
Receptive Vocabulary ◽  
Standardized Assessments ◽  
Cutoff Score ◽  
Invented Spelling ◽  
Reading Measures

The purpose of this study was to investigate informal phonological awareness measures as predictors of first-grade broad reading ability. Subjects were 91 former Head Start students who were administered standardized assessments of cognitive ability and receptive vocabulary, and informal phonological awareness measures during kindergarten and early first grade. Regression analyses indicated that three phonological awareness tasks, Invented Spelling, Categorization, and Blending, were the most predictive of standardized reading measures obtained at the end of first grade. Discriminant analyses indicated that these three phonological awareness tasks correctly identified at-risk students with 92% accuracy. Clinical use of a cutoff score for these measures is suggested, along with general intervention guidelines for practicing clinicians.

Effects of a Supplemental Spanish Phonological Awareness Intervention on Latinx Preschoolers' Dual Language Emergent Literacy Skills

2020 ◽  
Vol 29 (3) ◽  
pp. 1283-1300
Author(s):  
Xigrid T. Soto ◽  
Andres Crucet-Choi ◽  
Howard Goldstein
Keyword(s):  
At Risk ◽  
Phonological Awareness ◽  
Emergent Literacy ◽  
Language Learners ◽  
Literacy Instruction ◽  
Dual Language ◽  
Literacy Skills ◽  
Dual Language Learners ◽  
Probe Design ◽  
Emergent Literacy Skills

Purpose Preschoolers' phonological awareness (PA) and alphabet knowledge (AK) skills are two of the strongest predictors of future reading. Despite evidence that providing at-risk preschoolers with timely emergent literacy interventions can prevent academic difficulties, there is a scarcity of research focusing on Latinx preschoolers who are dual language learners. Despite evidence of benefits of providing Latinxs with Spanish emergent literacy instruction, few studies include preschoolers. This study examined the effects of a supplemental Spanish PA and AK intervention on the dual emergent literacy skills of at-risk Latinx preschoolers. Method A multiple probe design across four units of instruction evaluated the effects of a Spanish supplemental emergent literacy intervention that explicitly facilitated generalizations to English. Four Latinx preschoolers with limited emergent literacy skills in Spanish and English participated in this study. Bilingual researchers delivered scripted lessons targeting PA and AK skills in individual or small groups for 12–17 weeks. Results Children made large gains as each PA skill was introduced into intervention and generalized the PA skills they learned from Spanish to English. They also improved their English initial sound identification skills, a phonemic awareness task, when instruction was delivered in Spanish but with English words. Children made small to moderate gains in their Spanish letter naming and letter–sound correspondence skills and in generalizing this knowledge to English. Conclusion These findings provide preliminary evidence Latinx preschoolers who are dual language learners benefit from emergent literacy instruction that promotes their bilingual and biliterate development.

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