scholarly journals Temporal integration for amplitude modulation in childhood: Interaction between internal noise and memory

2021 ◽  
pp. 108403
Author(s):  
Laurianne Cabrera ◽  
Irene Lorenzini ◽  
Stuart Rosen ◽  
Léo Varnet ◽  
Christian Lorenzi
Keyword(s):  
Amplitude Modulation ◽  
Temporal Integration ◽  
Internal Noise

scholarly journals Temporal integration for amplitude modulation in childhood: Interaction between internal noise and memory factors

2021 ◽  
Author(s):  
Laurianne Cabrera ◽  
Irene Lorenzini ◽  
Stuart Rosen ◽  
léo varnet ◽  
Lorenzi Christian
Keyword(s):  
Amplitude Modulation ◽  
Short Term Memory ◽  
Temporal Integration ◽  
Age Groups ◽  
Computational Modelling ◽  
Internal Noise ◽  
Older Children ◽  
Processing Efficiency ◽  
Detection Thresholds ◽  
Gradual Improvement

It is still unclear whether the gradual improvement in amplitude-modulation (AM) sensitivity typically found in children up to 10 years of age reflects an improvement in “processing efficiency” (the central ability to use information extracted by sensory mechanisms). This hypothesis was tested by evaluating temporal integration for AM, a capacity relying on memory and decision factors. This was achieved by measuring the effect of increasing the number of AM cycles (2 vs 8) on AM-detection thresholds for three groups of children aged from 5 to 11 years and a group of young adults. AM- detection thresholds were measured using a forced-choice procedure and sinusoidal AM (4 or 32 Hz rate) applied to a 1024-Hz pure-tone carrier. All age groups demonstrated temporal integration for AM at both rates, that is significant improvements in AM sensitivity with a higher number of AM cycles. However, both 5- 6 years and adults exhibited similar levels of temporal integration, while 7-8 and 10- 11 years showed less integration. This is because at both rates: (i) the youngest group (5-6 years) displayed the worst thresholds with 2 AM cycles but similar thresholds with 8 cycles compared to older children groups, and (ii) adults showed the best thresholds with 8 AM cycles but similar thresholds with 2 cycles compared to older children groups. Computational modelling indicated that higher levels of internal noise combined with poorer short-term memory capacities in children accounted for the developmental trends. Improvement in processing efficiency may therefore account for the development of AM detection in childhood.

scholarly journals Amplitude Modulation detection ability can be differentially affected using state-dependent Transcranial Magnetic Stimulation

2017 ◽  
Author(s):  
Adam Michael Partridge ◽  
Garreth Prendergast ◽  
Mark Hymers
Keyword(s):  
Amplitude Modulation ◽  
Auditory Processing ◽  
Right Hemisphere ◽  
Temporal Integration ◽  
Broadband Noise ◽  
Detection Ability ◽  
Behavioural Adaptation ◽  
State Dependent ◽  
Left And Right ◽  
Auditory Cortices

Temporal changes in the speech envelope are crucial for intelligibility, and humans are particularly sensitive to amplitude modulations (AM) at frequencies commensurate with the syllabic rate (4Hz). Some asymmetric models of auditory processing have attempted to explain observed functional asymmetries between left and right auditory cortices in terms of temporal integration windows of differing lengths. In this paper we use an fMRI-localised, state-dependent, dual-pulse TMS paradigm to investigate auditory processing as exemplified by detection of sinusoidal amplitude modulation of a broadband noise carrier. The effect of left and right hemisphere TMS on accuracy levels for detection of such modulations at rates of 4 and 40Hz under conditions of behavioural adaptation were examined. Effects of TMS on AM detection were found only in the 40Hz detection task when TMS was applied to the left hemisphere. Further, this effect showed a dissociation based on the modulation used during behavioural adaptation, with a facilitation shown when participants were behaviourally adapted to 4Hz AM whereas a disruption was shown when participants were behaviourally adapted to 40Hz AM, contrary to initial predictions based on state-dependent TMS theory. These results show for the first time that it is possible to differentially affect AM detection ability using TMS and further emphasise the importance of subtle timing factors in TMS studies. The novel use of this technique in the auditory domain has implications for further elucidating auditory processing mechanisms in health and disease.

scholarly journals Neural Representations of Complex Temporal Modulations in the Human Auditory Cortex

2009 ◽  
Vol 102 (5) ◽  
pp. 2731-2743 ◽  
Author(s):  
Nai Ding ◽  
Jonathan Z. Simon
Keyword(s):  
Amplitude Modulation ◽  
Phase Locking ◽  
Temporal Integration ◽  
Neural Response ◽  
Neural Representation ◽  
High Rate ◽  
Instantaneous Amplitude ◽  
Static Compression ◽  
Stimulus Features ◽  
Auditory Steady State Responses

Natural sounds such as speech contain multiple levels and multiple types of temporal modulations. Because of nonlinearities of the auditory system, however, the neural response to multiple, simultaneous temporal modulations cannot be predicted from the neural responses to single modulations. Here we show the cortical neural representation of an auditory stimulus simultaneously frequency modulated (FM) at a high rate, fFM ≈ 40 Hz, and amplitude modulation (AM) at a slow rate, fAM <15 Hz. Magnetoencephalography recordings show fast FM and slow AM stimulus features evoke two separate but not independent auditory steady-state responses (aSSR) at fFM and fAM, respectively. The power, rather than phase locking, of the aSSR of both decreases with increasing stimulus fAM. The aSSR at fFM is itself simultaneously amplitude modulated and phase modulated with fundamental frequency fAM, showing that the slow stimulus AM is not only encoded in the neural response at fAM but also encoded in the instantaneous amplitude and phase of the neural response at fFM. Both the amplitude modulation and phase modulation of the aSSR at fFM are most salient for low stimulus fAM but remain observable at the highest tested fAM (13.8 Hz). The instantaneous amplitude of the aSSR at fFM is successfully predicted by a model containing temporal integration on two time scales, ∼25 and ∼200 ms, followed by a static compression nonlinearity.

scholarly journals Resting-State Alpha-Band Oscillations in Migraine

Perception ◽  
2018 ◽  
Vol 47 (4) ◽  
pp. 379-396 ◽  
Author(s):  
Louise O’Hare ◽  
Federica Menchinelli ◽  
Simon J. Durrant
Keyword(s):  
Resting State ◽  
Multiplicative Noise ◽  
Temporal Integration ◽  
Internal Noise ◽  
Control Group ◽  
Alpha Band ◽  
Control Groups ◽  
Eyes Closed ◽  
Before And After ◽  
And Control

Migraine groups show differences in motion perception compared with controls, when tested in between migraine attacks (interictally). This is thought to be due to an increased susceptibility to stimulus degradation (multiplicative internal noise). Fluctuations in alpha-band oscillations are thought to regulate visual perception, and so differences could provide a mechanism for the increased multiplicative noise seen in migraine. The aim of this article was to characterise resting-state alpha-band oscillations (between 8 and 12 Hz) in the visual areas of the brain in migraine and control groups. Alpha-band activity in the resting state (with eyes closed) was recorded before and after a visual psychophysics task to estimate equivalent noise, specifically a contrast detection task. The lower alpha-band (8 to 10 Hz) resting-state alpha-band power was increased in the migraine compared with the control group, which may provide a mechanism for increased multiplicative noise. In agreement with previous research, there were no differences found in the additive (baseline) internal noise, estimated using an equivalent noise task in the same observers. As fluctuations in alpha-band oscillations control the timing of perceptual processing, increased lower alpha-band (8 to 10 Hz) power could explain the behavioural differences in migraine compared with control groups, particularly on tasks relying on temporal integration.

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