Stewart H.J.,MRC Institute of Hearing Research |
Mcintosh R.D.,University of Edinburgh |
Williams J.H.G.,University of Aberdeen
Autism Research | Year: 2013
Imitation is a potentially crucial aspect of social cognitive development. Although deficits in imitation ability have been widely demonstrated in autism spectrum disorder (ASD), the specificity and significance of the findings is unclear, due largely to methodological limitations. We developed a novel assessment of imitation ability, using objective movement parameters (path length and action duration) derived from a touch-sensitive tablet laptop during drawing actions on an identical tablet. By direct comparison of the kinematics of a model's actions with those of the participant who observed them, measures of imitation accuracy were obtained. By replaying the end-point of the movement as a spot on the screen, imitation accuracy was compared against a "ghost control" condition, with no human actor but only the end-point of the movement seen [object movement reenactment (OMR)]. Hence, demands of the control task were closely matched to the experimental task with respect to motor, memory, and attentional abilities. Adolescents with ASD showed poorer accuracy for copying object size and action duration on both the imitation and OMR tasks, but were significantly more impaired for imitation of object size. Our results provide evidence that some of the imitation deficit in ASD is specific to a self-other mapping problem, and cannot be explained by general factors such as memory, spatial reasoning, motor control, or attention, nor related to the social demands of the testing situation. © 2013 International Society for Autism Research, Wiley Periodicals, Inc.
Banai K.,Haifa University |
Amitay S.,MRC Institute of Hearing Research
Vision Research | Year: 2012
Stimulus uncertainty produced by variations in a target stimulus to be detected or discriminated, impedes perceptual learning under some, but not all experimental conditions. To account for those discrepancies, it has been proposed that uncertainty is detrimental to learning when the interleaved stimuli or tasks are similar to each other but not when they are sufficiently distinct, or when it obstructs the downstream search required to gain access to fine-grained sensory information, as suggested by the Reverse Hierarchy Theory (RHT). The focus of the current review is on the effects of uncertainty on the perceptual learning of speech and non-speech auditory signals. Taken together, the findings from the auditory modality suggest that in addition to the accounts already described, uncertainty may contribute to learning when categorization of stimuli to phonological or acoustic categories is involved. Therefore, it appears that the differences reported between the learning of non-speech and speech-related parameters are not an outcome of inherent differences between those two domains, but rather due to the nature of the tasks often associated with those different stimuli. © 2012 Elsevier Ltd.
Agency: GTR | Branch: MRC | Program: | Phase: Intramural | Award Amount: 3.78M | Year: 2009
This programme aims to improve our understanding of the function and connectivity of the auditory system. Sound waves in the air are transformed by the exquisitely sensitive structures of the ear into fluid movements that activate sensory hair cells in the inner ear (cochlea) then communicate them to the brain where they can be analysed. Information is passed upwards from the cochlear nucleus, through a series of relay points, to the auditory cortex where sounds are consciously perceived. However, as well as this ascending path there is also an equally important descending path that modulates this ascending information dependent on context. We will study the interactions between these pathways both at the relay points and in the cortex using complex stimuli such as animal vocalizations. We will also study the consequences of hearing loss in creating imbalance in the two pathways and in inducing tinnitus. We will use an animal model of tinnitus to study the mechanisms that lead to tinnitus and to evaluate drug therapies that may reduce the auditory aspects of tinnitus.
Agency: GTR | Branch: MRC | Program: | Phase: Intramural | Award Amount: 1.17M | Year: 2009
Subjects with one deaf ear who have difficulties in localising sound and understanding speech in noisy conditions currently receive a hearing aid that redirects sounds at the deaf ear to the hearing ear. While improving audibility this does not solve the underlying difficulties. Such subjects may now receive a cochlear implant in the deaf ear. We are therefore conducting clinical trial across such subjects from five UK implant centres to compare the benefits of using the crossed hearing aid system to those from cochlear implantation. Participants will travel to the MRC IHR in Nottingham where their ability to understand speech and to locate sounds in space will be assessed under controlled conditions in specialist hearing laboratories.
Agency: GTR | Branch: MRC | Program: | Phase: Intramural | Award Amount: 3.46M | Year: 2009
The organisation and interpretation of the neural activity generated when we hear sounds is termed central auditory processing. We aim to understand the way in which sounds are represented in neuron’s firing in the brain: the ‘computations on sound’ performed by the brain and how the way we percieve sounds depends upon it. We do this with a combination of methods: measuring behaviour in response to sound, measuring directly the activity in neurons that process sound, and simulating on computers both how we percience sound and how neurons in the brain process it. For example, we are currently working how how neurons in the auditory system affect our ability to detect quiet signals in the presence of other sounds. These experiments complement other research designed to gain knowledge about normal and abnormal auditory processing in people and the development of therapeutic strategies for brain- and ear-based hearing disorders. Research on hearing in animals has led directly to the development of digital hearing aids and cochlear implants. However, in terms of quality of life the biggest impact of hearing impairment is on the ability to perceive sounds in noisy environments. Modern hearing aids and cochlear implants still do not help much with this, probably because we do not understand how people with normal hearing function in these situations. A deeper understanding of the mechanisms of auditory perception will improve the treatment of auditory related health problems.