Synaptic mechanisms of top-down control in the non-lemniscal inferior colliculus

Corticofugal projections to evolutionarily ancient, subcortical structures are ubiquitous across mammalian sensory systems. These ‘descending’ pathways enable the neocortex to control ascending sensory representations in a predictive or feedback manner, but the underlying cellular mechanisms are poorly understood. Here, we combine optogenetic approaches with in vivo and in vitro patch-clamp electrophysiology to study the projection from mouse auditory cortex to the inferior colliculus (IC), a major descending auditory pathway that controls IC neuron feature selectivity, plasticity, and auditory perceptual learning. Although individual auditory cortico-collicular synapses were generally weak, IC neurons often integrated inputs from multiple corticofugal axons that generated reliable, tonic depolarizations even during prolonged presynaptic activity. Latency measurements in vivo showed that descending signals reach the IC within 30 ms of sound onset, which in IC neurons corresponded to the peak of synaptic depolarizations evoked by short sounds. Activating ascending and descending pathways at latencies expected in vivo caused a NMDA receptor-dependent, supralinear excitatory postsynaptic potential summation, indicating that descending signals can nonlinearly amplify IC neurons’ moment-to-moment acoustic responses. Our results shed light upon the synaptic bases of descending sensory control and imply that heterosynaptic cooperativity contributes to the auditory cortico-collicular pathway’s role in plasticity and perceptual learning.

During Lipreading Training With Sentence Stimuli, Feedback Controls Learning and Generalization to Audiovisual Speech in Noise

Purpose: This study investigated the effects of external feedback on perceptual learning of visual speech during lipreading training with sentence stimuli. The goal was to improve visual-only (VO) speech recognition and increase accuracy of audiovisual (AV) speech recognition in noise. The rationale was that spoken word recognition depends on the accuracy of sublexical (phonemic/phonetic) speech perception; effective feedback during training must support sublexical perceptual learning. Method: Normal-hearing (NH) adults were assigned to one of three types of feedback: Sentence feedback was the entire sentence printed after responding to the stimulus. Word feedback was the correct response words and perceptually near but incorrect response words. Consonant feedback was correct response words and consonants in incorrect but perceptually near response words. Six training sessions were given. Pre- and posttraining testing included an untrained control group. Test stimuli were disyllable nonsense words for forced-choice consonant identification, and isolated words and sentences for open-set identification. Words and sentences were VO, AV, and audio-only (AO) with the audio in speech-shaped noise. Results: Lipreading accuracy increased during training. Pre- and posttraining tests of consonant identification showed no improvement beyond test–retest increases obtained by untrained controls. Isolated word recognition with a talker not seen during training showed that the control group improved more than the sentence group. Tests of untrained sentences showed that the consonant group significantly improved in all of the stimulus conditions (VO, AO, and AV). Its mean words correct scores increased by 9.2 percentage points for VO, 3.4 percentage points for AO, and 9.8 percentage points for AV stimuli. Conclusions: Consonant feedback during training with sentences stimuli significantly increased perceptual learning. The training generalized to untrained VO, AO, and AV sentence stimuli. Lipreading training has potential to significantly improve adults' face-to-face communication in noisy settings in which the talker can be seen.

Learning Styles of Saudi ESP Students

Explorations in learning styles have proved the significance of the ways students approach, assimilate, and process information. Students’ perceptions and their organization influence the quality of language learning and guide them towards autonomy, too. This study attempts to identify the preferred perceptual learning styles of 86 Saudi English for Specific Purposes (ESP) female students in the Preparatory Year Deanship, Prince Sattam bin Abdul Aziz University, Saudi Arabia. To accomplish this aim, a Perceptual Learning Style Preference Questionnaire (PLSPQ) developed by Joy Reid (1987) was used. The results showed that the participants’ major learning styles were Kinesthetic, Group, Auditory, Visual, and Tactile, whereas their minor style was Individual. The analysis of the data also revealed that the most preferred learning style was the Kinesthetic learning style (18.64%, M=4.42), and the least preferred one was the Individual learning style (14.30%, M=3.39). The second to fifth place belonged to Group (17.19%, M=4.07), Auditory (16.81%, M=3.98), Visual (16.55%, M=3.92) and Tactile (16.52%, M=3.91) learning styles. The findings have implications for teachers, syllabus designers, and researchers to take into consideration students’ preferred learning styles for language learning while teaching, changes in the learning environment, and material adaptation.

Mobile Learning in Business English its Effect to South American Students’ Learning Styles in the COVID 19 Pandemic Era: Its Economic Implications

The adoption of M-learning and perceptual learning style preferences of South American EFL learners in a business English course were studied empirically. A descriptive correlational research design was used in this study. Data were gathered from 125 South American EFL students who were carefully sampled among a total of 184 students with mobile phones enrolled in a business English classes of selected South American university. The Mobile Learning Questionnaire (MLQ) and Perceptual Learning Style Preference Questionnaire were used in the study (PLSPQ). The data revealed that students in a business English course have a high level of M-learning adoption. It was discovered that respondents favor visual learning, group learning, individual learning, tactile learning, and auditory learning, with kinesthetic learning receiving the least attention. When students are grouped by gender and age, test results show that male respondents had stronger appeal to the utility, acceptability, enjoyment, facilitating conditions, and behavioral intention of M-learning than female respondents. Regardless of their age, respondents acknowledged the benefits of using M-learning in their business English course. Similarly, when the respondents are grouped by gender, no significant differences in learning style preferences are detected. However, the younger respondents prefer group learning, whilst the older respondents prefer individual learning. Finally, a link was discovered between M-learning usage and students' preferred learning styles. The positive link implies that the more M-learning students use, the more learning style preferences they have for group, tactile, visual, auditory, kinesthetic, and group learning tasks. This paper discusses the theoretical and educational consequences.