Publications by authors named "Inga S Knoth"

4 Publications

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Differential auditory brain response abnormalities in two intellectual disability conditions: SYNGAP1 mutations and Down syndrome.

Clin Neurophysiol 2021 Aug 13;132(8):1802-1812. Epub 2021 May 13.

Department of Psychology, University of Montreal, Montreal, Québec, Canada; CHU Sainte-Justine Research Center, Montreal, Quebec, Canada. Electronic address:

Objective: Altered sensory processing is common in intellectual disability (ID). Here, we study electroencephalographic responses to auditory stimulation in human subjects presenting a rare condition (mutations in SYNGAP1) which causes ID, epilepsy and autism.

Methods: Auditory evoked potentials, time-frequency and inter-trial coherence analyses were used to compare subjects with SYNGAP1 mutations with Down syndrome (DS) and neurotypical (NT) participants (N = 61 ranging from three to 19 years of age).

Results: Altered synchronization in the brain responses to sound were found in both ID groups. The SYNGAP1 mutations group showed less phase-locking in early time windows and lower frequency bands compared to NT, and in later time windows compared to NT and DS. Time-frequency analysis showed more power in beta-gamma in the SYNGAP1 group compared to NT participants.

Conclusions: This study indicated reduced synchronization as well as more high frequencies power in SYNGAP1 mutations, while maintained synchronization was found in the DS group. These results might reflect dysfunctional sensory information processing caused by excitation/inhibition imbalance, or an imperfect compensatory mechanism in SYNGAP1 mutations individuals.

Significance: Our study is the first to reveal brain response abnormalities in auditory sensory processing in SYNGAP1 mutations individuals, that are distinct from DS, another ID condition.
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http://dx.doi.org/10.1016/j.clinph.2021.03.054DOI Listing
August 2021

Distinct patterns of repetition suppression in Fragile X syndrome, down syndrome, tuberous sclerosis complex and mutations in SYNGAP1.

Brain Res 2021 01 12;1751:147205. Epub 2020 Nov 12.

Psychology Departement, Université de Montréal, Pavillon Marie-Victorin, 90, Avenue Vincent d'Indy, Montréal, QC H2V 2S9, Canada; NED Laboratory, Office 5.2.43, 3175 Chemin de la Côte-Sainte-Catherine, Montréal, QC H3T 1C5, Canada; Research Center UHC Sainte-Justine, 3175 Chemin de la Côte-Sainte-Catherine, Montréal, QC H3T 1C5, Canada. Electronic address:

Sensory processing is the gateway to information processing and more complex processes such as learning. Alterations in sensory processing is a common phenotype of many genetic syndromes associated with intellectual disability (ID). It is currently unknown whether sensory processing alterations converge or diverge on brain responses between syndromes. Here, we compare for the first time four genetic conditions with ID using the same basic sensory learning paradigm. One hundred and five participants, aged between 3 and 30 years old, composing four clinical ID groups and one control group, were recruited: Fragile X syndrome (FXS; n = 14), tuberous sclerosis complex (TSC; n = 9), Down syndrome (DS; n = 19), SYNGAP1 mutations (n = 8) and Neurotypical controls (NT; n = 55)). All groups included female and male participants. Brain responses were recorded using electroencephalography (EEG) during an audio-visual task that involved three repetitions of the pronunciation of the phoneme /a/. Event Related Potentials (ERP) were used to: 1) compare peak-to-peak amplitudes between groups, 2) evaluate the presence of repetition suppression within each group and 3) compare the relative repetition suppression between groups. Our results revealed larger overall amplitudes in FXS. A repetition suppression (RS) pattern was found in the NT group, FXS and DS, suggesting spared repetition suppression in a multimodal task in these two ID syndromes. Interestingly, FXS presented a stronger RS on one peak-to-peak value in comparison with the NT. The results of our study reveal the distinctiveness of ERP and RS brain responses in ID syndromes. Further studies should be conducted to understand the molecular mechanisms involved in these patterns of responses.
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http://dx.doi.org/10.1016/j.brainres.2020.147205DOI Listing
January 2021

Altered visual repetition suppression in Fragile X Syndrome: New evidence from ERPs and oscillatory activity.

Int J Dev Neurosci 2017 Jun 19;59:52-59. Epub 2017 Mar 19.

Departement de Psychologie, Université de Montréal, Montreal, Canada; Neuroscience of Early Development (NED), Montreal, Canada; Centre de Recherche en Neuropsychologie et Cognition (CERNEC), Montreal, Canada; Research Center of the CHU Ste-Justine Mother and Child University Hospital Center, Université de Montreal, Quebec, Canada; International Laboratory for Brain, Music and Sound Research (BRAMS), Montreal, Quebec, Canada.

Fragile X Syndrome (FXS) is a neurodevelopmental genetic disorder associated with cognitive and behavioural deficits. In particular, neuronal habituation processes have been shown to be altered in FXS patients. Yet, while such deficits have been primarily explored using auditory stimuli, less is known in the visual modality. Here, we investigated the putative alteration of repetition suppression using faces in FXS patients compared to controls that had the same age distribution. Electroencephalographic (EEG) signals were acquired while participants were presented with 18 different faces, each repeated ten times successively. The repetition suppression effect was probed by comparing the brain responses to the first and second presentation, based on task-evoked event-related potentials (ERP) as well as on task-induced oscillatory activity. We found different patterns of habituation for controls and patients both in ERP and oscillatory power. While the N170 was not affected by face repetition in controls, it was altered in FXS patients. Conversely, while a repetition suppression effect was observed in the theta band (4-8Hz) over frontal and parieto-occipital areas in controls, it was not seen in FXS patients. These results provide the first evidence for diminished ERP and oscillatory habituation effects in response to face repetitions in FXS. These findings extend previous observations of impairments in learning mechanisms and may be linked to deficits in the maturation processes of synapses caused by the mutation. The present study contributes to bridging the gap between animal models of synaptic plasticity dysfunctions and human research in FXS.
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http://dx.doi.org/10.1016/j.ijdevneu.2017.03.008DOI Listing
June 2017

Event-related potential alterations in fragile X syndrome.

Front Hum Neurosci 2012 24;6:264. Epub 2012 Sep 24.

Centre de Recherche CHU Ste-Justine, University of Montreal Montreal, QC, Canada ; Centre de Recherche en Neuropsychologie et Cognition, University of Montreal Montreal, QC, Canada.

Fragile X Syndrome (FXS) is the most common form of X-linked intellectual disability (ID), associated with a wide range of cognitive and behavioral impairments. FXS is caused by a trinucleotide repeat expansion in the FMR1 gene located on the X-chromosome. FMR1 is expected to prevent the expression of the "fragile X mental retardation protein (FMRP)", which results in altered structural and functional development of the synapse, including a loss of synaptic plasticity. This review aims to unveil the contribution of electrophysiological signal studies for the understanding of the information processing impairments in FXS patients. We discuss relevant event-related potential (ERP) studies conducted with full mutation FXS patients and clinical populations sharing symptoms with FXS in a developmental perspective. Specific deviances found in FXS ERP profiles are described. Alterations are reported in N1, P2, Mismatch Negativity (MMN), N2, and P3 components in FXS compared to healthy controls. Particularly, deviances in N1 and P2 amplitude seem to be specific to FXS. The presented results suggest a cascade of impaired information processes that are in line with symptoms and anatomical findings in FXS.
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http://dx.doi.org/10.3389/fnhum.2012.00264DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3449440PMC
October 2012
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