Temporal integration (TI; threshold versus stimulus duration) functions and multipulse integration (MPI; threshold versus pulse rate) functions were measured behaviorally in guinea pigs and humans with cochlear implants. described in the statistical “multiple looks” model. Histological analysis of the guinea pig cochleae suggested that the slopes of both the MPI and the TI functions were dependent on sensory and neural health near the stimulated regions. The strongest predictor for spiral ganglion cell densities measured near the stimulation sites was the slope of the MPI functions below 1 0 pps. Several mechanisms may be considered to account for the association of shallow integration functions with poor sensory and neural status. These mechanisms are related to abnormal across-fiber synchronization increased refractoriness and adaptation with impaired neural function and steep growth of neural excitation with current level associated with neural pathology. The slope of the integration functions can potentially be used as a non-invasive measure for identifying stimulation sites with poor neural health and selecting those sites for removal or rehabilitation but these applications remain to be tested. or AAV.inoculation and cochlear implantation ((49)?=?10.04 (23)?=?5.78 revealed that in the pulse range common to both subject groups i.e. approximately 78-625 pps the slopes of the MPI functions measured in humans Rabbit Polyclonal to LRP3. were not statistically different than those measured in guinea pigs as a whole group [(72)?=??0.59 (40)?=??2.02 (see legend in Figure ?Figure2)2) and for group mean in … FIG. 2 Scatter plot for the slopes of the first and second arm of the MPI functions measured in guinea pigs (represent different guinea pig groups: = implanted in a hearing ear; = implanted … Temporal Integration Functions Figure ?Figure33 shows individual and group mean TI functions obtained from the guinea pig subjects (left panel) and the human subjects (right panel). The slopes of the TI functions measured in humans were not statistically different to those measured in guinea pigs in a similar stimulus-duration range i.e. 40 ms [(51)?=??0.605 (see legend in Figure LX 1606 ?Figure2)2) and for group mean in … Relationship Between the Two Integration Functions The magnitudes of the TI and MPI function slopes were compared for each subject group. For guinea pigs slopes of the MPI functions were LX 1606 significantly steeper than those of the TI functions [(27)?=?9.6 (27)?=?2.16 (27)?=?14.75 (23)?=?4.69 (23)?=?6.9 (1)?=?18.76 (1)?=?8.863 represent different guinea pig groups (please see “Methods” for details of the organizations). The one guinea pig data … Relationship Between the Integration Actions and Cochlear Health Histological and electrophysiological data from your guinea pigs included SGN denseness IHC counts and ESA levels recorded from your electrode of interest. Collectively we refer to these data as actions of cochlear health. Correlations between each pair of the three cochlear health variables and their marginal correlations (correlations disregarding other variables) with the various integration slopes are demonstrated in Table ?Table33 (note that the sign of the correlations was bad indicating more bad slopes predicting healthier cochlea). All marginal correlations were significant except for MPI slopes above 1 0 pps with SGN denseness and TI slopes with ESA levels. A regression analysis exposed that for the first arm of the MPI function (<313 pps) IHC survival was found to become the strongest predictor [(1)?=?45.76 (1)?=?23.72 (2)?=?25.10 (2)?=?8.51 (1)?=?15.16 (1)?=?43.14 represent different guinea pig organizations (please LX 1606 see Number ?Number22 caption ... Conversation The present study examined detection threshold LX 1606 versus pulse rate (MPI) functions and detection threshold versus stimulus period (TI) functions in guinea pigs and humans with cochlear implants. In order to understand whether the effect of cochlear health within the integration slopes in guinea pigs reported previously (Kang et al. 2010; Pfingst et al. 2011) and here can be extrapolated in human being subjects we compared the characteristics of the two integration functions between the two subject groups. Magnitude of the slopes for the MPI functions was not different between the two subject groups in the pulse rate range common to both organizations and so was the magnitude of the TI functions in the common stimulus duration range. The two subject groups shared another characteristic in the integration functions. That is the magnitude of the TI function slopes was similar to that of the MPI function slopes only in the low pulse rate range. This was due to a trend.