Humans have a remarkable ability to track and understand speech in unfavorable conditions, such as background noise, but understanding noise does deteriorate with age. Results from several studies shown that younger adults, low-frequency auditory cortical activity reliably synchronizes the envelope, even when is considerably louder than signal. However, processing may be limited by age-related decreases precision of neural synchronization midbrain. To better mechanisms contributing impaired...

Chronic recordings from ensembles of cortical neurons in primary motor and somatosensory areas rhesus macaques provide accurate information about bipedal locomotion (Fitzsimmons NA, Lebedev MA, Peikon ID, Nicolelis MA. Front Integr Neurosci 3: 3, 2009). Here we show that the linear angular kinematics ankle, knee, hip joints during both normal precision (attentive) human treadmill walking can be inferred noninvasive scalp electroencephalography (EEG) with decoding accuracies comparable to...

Age-related deficits in speech-in-noise understanding pose a significant problem for older adults. Despite the vast number of studies conducted to investigate neural mechanisms responsible these communication difficulties, role central auditory deficits, beyond peripheral hearing loss, remains unclear. The current study builds upon our previous work that investigated effect aging on normal-hearing individuals and aims estimate loss representation speech noise two critical regions pathway:...

Brain-machine interface (BMI) research has largely been focused on the upper limb. Although restoration of gait function a long-standing focus rehabilitation research, surprisingly very little done to decode cortical neural networks involved in guidance and control bipedal locomotion. A notable exception is work by Nicolelis' group at Duke University that decoded kinematics from chronic recordings ensembles neurons primary sensorimotor areas rhesus monkeys. Recently, we showed ankle, knee,...

The ability to understand speech is significantly degraded by aging, particularly in noisy environments. One way that older adults cope with this hearing difficulty through the use of contextual cues. Several behavioral studies have shown are better at following a conversation when target signal has high content or background distractor not meaningful. Specifically, gain significant benefit focusing on and understanding if spoken talker language comprehensible them (i.e., foreign language)....

Neural processing along the ascending auditory pathway is often associated with a progressive reduction in characteristic rates. For instance, well-known frequency-following response (FFR) of midbrain, as measured electroencephalography (EEG), dominated by frequencies from ∼100 Hz to several hundred Hz, phase-locking acoustic stimulus at those frequencies. In contrast, cortical responses, whether EEG or magnetoencephalography (MEG), are typically characterized few tens time-locking envelope...

Previous research has found that, paradoxically, while older adults have more difficulty comprehending speech in challenging circumstances than younger adults, their brain responses track the envelope of acoustic signal robustly. Here we investigate this puzzle by using magnetoencephalography (MEG) source localization to determine anatomical origin difference. Our results indicate that robust tracking does not arise merely from having same as but with larger amplitudes; instead, they recruit...

We observed age-related changes in cortical temporal processing of continuous speech that may be related to older adults’ difficulty understanding noise. These occur both timing and strength the representations at different stages depend on noise condition selective attention. Critically, their dependence dramatically among early, middle, late stages, underscoring how aging differentially affects these stages.

The authors investigated aging effects on the envelope of frequency following response to dynamic and static components speech. Older adults frequently experience problems understanding speech, despite having clinically normal hearing. Improving audibility with hearing aids provides variable benefit, as amplification cannot restore temporal precision degraded by aging. Previous studies have demonstrated age-related delays in subcortical timing specific dynamic, transition region stimulus....

Older adults often have trouble adjusting to hearing aids when they start wearing them for the first time. Probe microphone measurements verify appropriate levels of amplification up tympanic membrane. Little is known, however, about effects on auditory-evoked responses speech stimuli during initial aid use. The present study assesses neural encoding a signal in older using It was hypothesized that results improved stimulus (higher amplitudes, phase locking, and earlier latencies), with...

Cortical representations of natural speech are investigated using a novel nonlinear approach based on mutual information. responses, phase-locked to the envelope, show an exaggerated level information associated with aging, appearing at several distinct latencies (∼50, ∼100, and ∼200 ms). Critically, for older listeners only, ms latency response components correlated specific behavioral measures, including inhibition comprehension.

Purpose This study investigates the development of phase locking and frequency representation in infants using frequency-following response to consonant–vowel syllables. Method The was recorded 56 15 young adults 2 speech syllables (/ba/ /ga/), which were presented randomized order right ear. Signal-to-noise ratio F sp analyses used verify that individual responses present above noise floor. Thirty-six 39 met these criteria for /ba/ or /ga/ syllables, respectively, 31 both Data analyzed...

Before 2009, the feasibility of applying brain-machine interfaces (BMIs) to control prosthetic devices had been limited upper limb prosthetics such as DARPA modular limb. Until recently, it was believed that bipedal locomotion involved central pattern generators with little supraspinal control. Analysis cortical dynamics electroencephalography (EEG) also prevented by lack analysis tools deal excessive signal artifacts associated walking. Recently, Nicolelis and colleagues paved way for...

Despite the frequency with which individuals perform in team environments of differing quality as well robust relationship between cerebral cortical processes/ attentional reserve and cognitive–motor performance, impact environment on processes has not been investigated. The purpose present study was to address this shortcoming. Using electroencephalography (EEG), we found that exhibited reduced activation increased when performing adaptive neutral compared a maladaptive environment....

Younger adults with normal hearing can typically understand speech in the presence of a competing speaker without much effort, but this ability to challenging conditions deteriorates age. Older adults, even clinically hearing, often have problems understanding noise. Earlier auditory studies using frequency-following response (FFR), primarily believed be generated by midbrain, demonstrated age-related neural deficits when analyzed traditional measures. Here we use mutual information paradigm...

Estimating the latent dynamics underlying biological processes is a central problem in computational biology. State-space models with Gaussian statistics are widely used for estimation of such and have been successfully utilized analysis data. statistics, however, fail to capture several key features (e.g., brain dynamics) as abrupt state changes exogenous that affect states structured fashion. Although mixture process noise considered an alternative effects, data-driven inference their...

Objectives: Several studies have investigated the feasibility of using electrophysiology as an objective tool to efficiently map cochlear implants. A pervasive problem when measuring event-related potentials is need remove direct-current (DC) artifact produced by implant. Here, we describe how DC removal can corrupt response waveform and appropriate choice stimulus duration may minimize this corruption. Design: Event-related were recorded a synthesized vowel /a/ with 170- or 400-ms duration....

In the last few years, a large number of experiments have been focused on exploring possibility using non-invasive techniques, such as electroencephalography (EEG) and magnetoencephalography (MEG), to identify auditory-related neuromarkers which are modulated by attention. Results from several studies where participants listen story narrated one speaker, while trying ignore different competing suggest feasibility extracting that demonstrate enhanced phase locking attended speech stream....