What memory representation is acquired during nonword speech production learning? The influence of stimulus features and training modality on nonword encoding

The purpose of this research was to investigate memory representations related to speech processing. Psycholinguistic and speech motor control theorists have hypothesized a variety of fundamental memory representations, such as syllables or phonemes, which may be learned during speech acquisition tasks. Yet, it remains unclear which fundamental representations are encoded and retrieved during learning and generalization tasks. Two experiments were conducted using a motor learning paradigm to investigate if representations for syllables and phonemes were acquired during a nonword repetition task. Additionally, different training modalities were implemented across studies to examine if training modality influenced memory encoding for nonword stimuli. Results suggest multiple representations may be acquired during training regardless of training modality; however, the underlying memory representations learned during training may be less abstract than current models hypothesize

THE INFLUENCE OF SPEECH PRODUCTION EXPERIENCE ON THE SIZE AND THE STRUCTURE OF THE SPEECH MOTOR PROGRAM

Schema theory (1975) proposed that information about relative timing and force of movements and the order of motor events is stored in Generalized Motor Programs (GMPs). Because some researchers (e. g., Löfqvist, 1991; Max & Caruso, 1997) observed consistent relative timing information in some, but not all, speech rate contexts, this study attempted to provide an alternative explanation for these inconsistent findings of proportional relationships in the trajectories of speech movements. Motivated by Verwey and colleagues (1995, 1996; 1996), who observed changes in production modes from preparing a key press motor response in advance to preparing it in a concurrent manner as the sequence length increased, this study proposes two possible reasons for increased variability in movement trajectories: various motor program sizes and changes in the production mode between advance programming and concurrent programming. The current study hypothesizes that more experienced speakers preserve more proportional relationship information, utilize larger size stored motor programs, and make more flexible switches in their production modes. Twenty-four native Mandarin and twenty-four non-Mandarin male speakers (19-30 years of age) with normal speech and language functions were recruited. They produced three-syllable, six-syllable, and nine-syllable length Mandarin tone sequences. Interactions between Group and Sequence Length Conditions were investigated in the hierarchical generalized linear model. Several timing, GMP error, and parameter error measurements were examined. Significant interactions were observed between Group and Sequence Length Condition on the GMP errors per syllable, Hamming distance difference per syllable between slope and parsons’ code measurements, and Hamming distance per syllable for parsons’ code measurement. In addition, many other significant Group and Sequence Length Condition main or simple main effects were observed. Results revealed that once motor programs are retrieved, they are executed without being reparameterized. The existence of GMP for lexical tones was supported. Also, it appeared that both native Mandarin and non-Mandarin speakers could switch between advance programming and concurrent programming as the sequence length increased. The timing of this switch occurred later in more-experienced speakers. Furthermore, the attempt to concatenate motor programs appeared to increase variability in movement outcome trajectories, supporting the hypotheses of this study

Subthalamic Nucleus and Sensorimotor Cortex Activity During Speech Production

The sensorimotor cortex is somatotopically organized to represent the vocal tract articulators such as lips, tongue, larynx, and jaw. How speech and articulatory features are encoded at the subcortical level, however, remains largely unknown. We analyzed LFP recordings from the subthalamic nucleus (STN) and simultaneous electrocorticography recordings from the sensorimotor cortex of 11 human subjects (1 female) with Parkinson´s disease during implantation of deep-brain stimulation (DBS) electrodes while they read aloud three-phoneme words. The initial phonemes involved either articulation primarily with the tongue (coronal consonants) or the lips (labial consonants). We observed significant increases in high-gamma (60?150 Hz) power in both the STN and the sensorimotor cortex that began before speech onset and persisted for the duration of speech articulation. As expected from previous reports, in the sensorimotor cortex, the primary articulators involved in the production of the initial consonants were topographically represented by high-gamma activity. We found that STN high-gamma activity also demonstrated specificity for the primary articulator, although no clear topography was observed. In general, subthalamic high-gamma activity varied along the ventral?dorsal trajectory of the electrodes, with greater high-gamma power recorded in the dorsal locations of the STN. Interestingly, the majority of significant articulator-discriminative activity in the STN occurred before that in sensorimotor cortex. These results demonstrate that articulator-specific speech information is contained within high-gamma activity of the STN, but with different spatial and temporal organization compared with similar information encoded in the sensorimotor cortex.Fil: Chrabaszcz, Anna. University of Pittsburgh; Estados UnidosFil: Neumann, Wolf Julian. Universität zu Berlin; AlemaniaFil: Stretcu, Otilia. University of Pittsburgh; Estados UnidosFil: Lipski, Witold J.. University of Pittsburgh; Estados UnidosFil: Dastolfo Hromack, Christina A.. University of Pittsburgh; Estados UnidosFil: Bush, Alan. University of Pittsburgh; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Wang, Dengyu. Tsinghua University; China. University of Pittsburgh; Estados UnidosFil: Crammond, Donald J.. University of Pittsburgh; Estados UnidosFil: Shaiman, Susan. University of Pittsburgh; Estados UnidosFil: Dickey, Michael W.. University of Pittsburgh; Estados UnidosFil: Holt, Lori L.. University of Pittsburgh; Estados UnidosFil: Turner, Robert S.. University of Pittsburgh; Estados UnidosFil: Fiez, Julie A.. University of Pittsburgh; Estados UnidosFil: Richardson, R. Mark. University of Pittsburgh; Estados Unido

Comparison of swallowing outcomes in single vs. double lung transplant recipients

Swallowing is a physiologically complex, kinematic process that requires highly coordinated activity of numerous nerves and muscles to execute efficient transport of a bolus from the oral cavity to the stomach. Dysphagia, or a difficulty with swallowing, is a concern following lung transplantation due to the high risk of recurrent laryngeal nerve damage, required levels of life-long immunosuppression, and upper airway trauma secondary to prolonged endotracheal intubation (Pomfret, 2016). Post-operatively, repetitive aspiration events can lead to the development of Bronchiolitis Obliterans Syndrome (BOS), a major contributing factor in acute allograft rejection and long-term failure of lung allograft function. The goal of this descriptive, retrospective study is to describe the characteristics of double lung transplant (DLT) swallows through analysis of kinematic swallow durations, airway protection, and physiologic swallow impairments. These results are compared to single lung transplant (SLT) swallow characteristics and two previously published, historical normal cohorts. By explicitly describing the swallow physiology of DLT and SLT recipients, clinically significant risk factors have been identified to assist clinicians and researchers in the development and implementation of better treatment options and safer swallowing strategies post-operatively. These efforts can improve the functional lifespan of the newly transplanted organ and increase patient quality of life

What memory representation is acquired during nonword speech production learning? The influence of stimulus features and training modality on nonword encoding

The purpose of this research was to investigate memory representations related to speech processing. Psycholinguistic and speech motor control theorists have hypothesized a variety of fundamental memory representations, such as syllables or phonemes, which may be learned during speech acquisition tasks. Yet, it remains unclear which fundamental representations are encoded and retrieved during learning and generalization tasks. Two experiments were conducted using a motor learning paradigm to investigate if representations for syllables and phonemes were acquired during a nonword repetition task. Additionally, different training modalities were implemented across studies to examine if training modality influenced memory encoding for nonword stimuli. Results suggest multiple representations may be acquired during training regardless of training modality; however, the underlying memory representations learned during training may be less abstract than current models hypothesize