Sahar Akram

  • Citations Per Year
Learn More
The underlying mechanism of how the human brain solves the cocktail party problem is largely unknown. Recent neuroimaging studies, however, suggest salient temporal correlations between the auditory neural response and the attended auditory object. Using magnetoencephalography (MEG) recordings of the neural responses of human subjects, we propose a decoding(More)
Humans are able to segregate auditory objects in a complex acoustic scene, through an interplay of bottom-up feature extraction and top-down selective attention in the brain. The detailed mechanism underlying this process is largely unknown and the ability to mimic this procedure is an important problem in artificial intelligence and computational(More)
A novel method for speech enhancement based on Convolutive Non-negative Matrix Factorization (CNMF) is presented in this paper. The sparsity of activation matrix for speech components has already been utilized in NMF-based enhancement methods. However such methods do not usually take into account prior knowledge about occurrence relations between different(More)
OBJECTIVE A central problem in computational neuroscience is to characterize brain function using neural activity recorded from the brain in response to sensory inputs with statistical confidence. Most of existing estimation techniques, such as those based on reverse correlation, exhibit two main limitations: first, they are unable to produce dynamic(More)
A new multimodal framework for speech enhancement in noisy environments based on human auditory system model is proposed in this paper. Unlike existing engineering architectures each of which specifically designed for certain speech sensors (extracted pitch, visual cues, etc.), our proposed model provides the capacity to integrate cues of different type(More)
Humans routinely segregate a complex acoustic scene into different auditory streams, through the extraction of bottom-up perceptual cues and the use of top-down selective attention. To determine the neural mechanisms underlying this process, neural responses obtained through magnetoencephalography (MEG) were correlated with behavioral performance in the(More)
A perceptual phenomenon is reported, whereby prior acoustic context has a large, rapid and long-lasting effect on a basic auditory judgement. Pairs of tones were devised to include ambiguous transitions between frequency components, such that listeners were equally likely to report an upward or downward 'pitch' shift between tones. We show that presenting(More)
The context in which a stimulus occurs can influence its perception. We study contextual effects in audition using the tritone paradox, where a pair of complex (Shepard) tones separated by half an octave can be perceived as ascending or descending. While ambiguous in isolation, they are heard with a clear upward or downward change in pitch, when preceded by(More)
  • 1