The Relationship between Auditory Sensory Gating and Cognitive Functions on Auditory and

ObjectivesConsidering the common neurological origins, there is a relationship between the sensory gating and cognitive functions. However, there is no adequate information on this issue. In this study, auditory event-related potentials and the sensory gating performance were assessed in P50, N100 and P200 waves. Besides, their relationship with cognitive performance in auditory and visual modalities was investigated.Materials & MethodsNineteen normal primary school students (14 boys) were tested in Tehran, Iran from 2017 to 2018. In the auditory modality, the Persian version of the non-word repetition test and monaural selective auditory attention test (mSAAT) were used for assessment of the working memory and selective attention, respectively. In order to evaluate the visual working memory and visual selective attention, Rey-Osterrieth complex figure, selective and divided attention test were used, respectively. A 32-channel EEG system was used for electrophysiological assessment.ResultsThe P50 sensory gating was negatively correlated with the visual selective attention (P=0.034, r=-0.49) and N100 sensory gating was negatively correlated with the auditory working memory (P=0.043, r=-0.48) as well as visual selective attention (P=0.039, r=-0.47). For P200, there was a significant negative relationship with auditory selective attention in the right ear (P=0.034, r=-0.49).ConclusionSensory gating in children is not a modality-specific phenomenon. Sensory gating in a modality could be associated with cognitive functions in other modalitie

Frontal and superior temporal auditory processing abnormalities in schizophrenia

AbstractBackgroundAlthough magnetoencephalography (MEG) studies show superior temporal gyrus (STG) auditory processing abnormalities in schizophrenia at 50 and 100ms, EEG and corticography studies suggest involvement of additional brain areas (e.g., frontal areas) during this interval. Study goals were to identify 30 to 130ms auditory encoding processes in schizophrenia (SZ) and healthy controls (HC) and group differences throughout the cortex.MethodsThe standard paired-click task was administered to 19 SZ and 21 HC subjects during MEG recording. Vector-based Spatial–temporal Analysis using L1-minimum-norm (VESTAL) provided 4D maps of activity from 30 to 130ms. Within-group t-tests compared post-stimulus 50ms and 100ms activity to baseline. Between-group t-tests examined 50 and 100ms group differences.ResultsBilateral 50 and 100ms STG activity was observed in both groups. HC had stronger bilateral 50 and 100ms STG activity than SZ. In addition to the STG group difference, non-STG activity was also observed in both groups. For example, whereas HC had stronger left and right inferior frontal gyrus activity than SZ, SZ had stronger right superior frontal gyrus and left supramarginal gyrus activity than HC.ConclusionsLess STG activity was observed in SZ than HC, indicating encoding problems in SZ. Yet auditory encoding abnormalities are not specific to STG, as group differences were observed in frontal and SMG areas. Thus, present findings indicate that individuals with SZ show abnormalities in multiple nodes of a concurrently activated auditory network

Neurobiology Underlying Fibromyalgia Symptoms

Fibromyalgia is characterized by chronic widespread pain, clinical symptoms that include cognitive and sleep disturbances, and other abnormalities such as increased sensitivity to painful stimuli, increased sensitivity to multiple sensory modalities, and altered pain modulatory mechanisms. Here we relate experimental findings of fibromyalgia symptoms to anatomical and functional brain changes. Neuroimaging studies show augmented sensory processing in pain-related areas, which, together with gray matter decreases and neurochemical abnormalities in areas related to pain modulation, supports the psychophysical evidence of altered pain perception and inhibition. Gray matter decreases in areas related to emotional decision making and working memory suggest that cognitive disturbances could be related to brain alterations. Altered levels of neurotransmitters involved in sleep regulation link disordered sleep to neurochemical abnormalities. Thus, current evidence supports the view that at least some fibromyalgia symptoms are associated with brain dysfunctions or alterations, giving the long-held “it is all in your head” view of the disorder a new meaning

Large-Scale Networks for Auditory Sensory Gating in the Awake Mouse

The amplitude of the brain response to a repeated auditory stimulus is diminished as compared to the response to the first tone (T1) for interstimulus intervals (ISI) lasting up to hundreds of milliseconds. This adaptation process, called auditory sensory gating (ASG), is altered in various psychiatric diseases including schizophrenia and is classically studied by focusing on early evoked cortical responses to the second tone (T2) using 500-ms ISI. However, mechanisms underlying ASG are still not well-understood. We investigated ASG in awake mice from the brainstem to cortex at variable ISIs (125-2000 ms) using high-density EEG and intracerebral recordings. While ASG decreases at longer ISIs, it is still present at durations (500-2000 ms) far beyond the time during which brain responses to T1 could still be detected. T1 induces a sequence of specific stable scalp EEG topographies that correspond to the successive activation of distinct neural networks lasting about 350 ms. These brain states remain unaltered if T2 is presented during this period, although T2 is processed by the brain, suggesting that ongoing networks of brain activity are active for longer than early evoked-potentials and are not overwritten by an upcoming new stimulus. Intracerebral recordings demonstrate that ASG is already present at the level of ventral cochlear nucleus (vCN) and inferior colliculus and is amplified across the hierarchy in bottom-up direction. This study uncovers the extended stability of sensory-evoked brain states and long duration of ASG, and sheds light on generators of ASG and possible interactions between bottom-up and top-down mechanisms

Individuals with 22q11.2 deletion syndrome show intact prediction but reduced adaptation in responses to repeated sounds:Evidence from Bayesian mapping

One of the most common copy number variants, the 22q11.2 microdeletion, confers an increased risk for schizophrenia. Since schizophrenia has been associated with an aberrant neural response to repeated stimuli through both reduced adaptation and prediction, we here hypothesized that this may also be the case in nonpsychotic individuals with a 22q11.2 deletion.We recorded high-density EEG from 19 individuals with 22q11.2 deletion syndrome (12–25 years), as well as 27 healthy volunteers with comparable age and sex distribution, while they listened to a sequence of sounds arranged in a roving oddball paradigm. Using posterior probability maps and dynamic causal modelling we tested three different models accounting for repetition dependent changes in cortical responses as well as in effective connectivity; namely an adaptation model, a prediction model, and a model including both adaptation and prediction.Repetition-dependent changes were parametrically modulated by a combination of adaptation and prediction and were apparent in both cortical responses and in the underlying effective connectivity. This effect was reduced in individuals with a 22q11.2 deletion and was negatively correlated with negative symptom severity. Follow-up analysis showed that the reduced effect of the combined adaptation and prediction model seen in individuals with 22q11.2 deletion was driven by reduced adaptation rather than prediction failure. Our findings suggest that adaptation is reduced in individuals with a 22q11.2 deletion, which can be interpreted in light of the framework of predictive coding as a failure to suppress prediction errors. Keywords: 22q11 deletion syndrome, Dynamic causal modelling, Posterior probability maps, EEG, Mismatch negativity, Repetition suppressio

Multisensory cortical processing and dysfunction across the neuropsychiatric spectrum

Sensory processing is affected in multiple neuropsychiatric disorders like schizophrenia and autism spectrum disorders. Genetic and environmental factors guide the formation and fine-tuning of brain circuitry necessary to receive, organize, and respond to sensory input in order to behave in a meaningful and consistent manner. During certain developmental stages the brain is sensitive to intrinsic and external factors. For example, disturbed expression levels of certain risk genes during critical neurodevelopmental periods may lead to exaggerated brain plasticity processes within the sensory circuits, and sensory stimulation immediately after birth contributes to fine-tuning of these circuits. Here, the neurodevelopmental trajectory of sensory circuit development will be described and related to some example risk gene mutations that are found in neuropsychiatric disorders. Subsequently, the flow of sensory information through these circuits and the relationship to synaptic plasticity will be described. Research focusing on the combined analyses of neural circuit development and functioning are necessary to expand our understanding of sensory processing and behavioral deficits that are relevant across the neuropsychiatric spectrum

The P50 auditory potential: A potential neurophysiological marker of Alzheimers disease

This auditory event-related potential (ERP) study investigated a candidate neurophysiological marker of Alzheimers disease (AD) and symptom severity. ERPs are sensitive to disruption of cortical processing and therefore have been used to study cortical effects of AD. The P50 ERP component has been shown to increase in amplitude with healthy aging, with multiple-domain relative to single-domain mild cognitive impairment (MCI), and in MCI patients who convert to AD compared to those whose diagnoses remain stable. As “MCI due to AD” has recently been defined as the symptomatic predementia phase of AD, P50 amplitude may reflect changes underlying AD progression in the earliest stages and is expected to vary as a function of cognitive impairment. There is also evidence to support P50 amplitude decrease in AD compared to MCI patients and conflict in the literature as to whether P50 is larger in AD relative to age-matched controls. This study explores P50 amplitude as a marker to distinguish mild AD patients from healthy older controls as well as the relationship between P50 amplitude and symptom severity, as measured by the Mini Mental Status Exam (MMSE).M.S., Clinical Psychology -- Drexel University, 201

The Impact of Short-Term Sleep Extension on Cognitive and Motor Performance in College Tactical Athletes

U.S. service members are commonly referred to as “tactical athletes” because of the physical training they undergo to maintain and improve occupational performance. Because performance in the military can literally determine the outcome in ‘life and death’ situations, it is critical that tactical athletes are prepared to perform optimally, both physically and mentally. Accordingly, it is important for tactical athletes to focus on health behaviors, like sleep, known to impact both aspects of performance. Little is known about the sleep health of college tactical athletes enrolled in The Reserve Officer's Training Corps (ROTC) and there have been no well-controlled studies on the immediate and residual effects of sleep extension on executive and cognitive motor performance. To address this knowledge gap, a randomized control trial (Sleep extension versus Control) was conducted to determine the immediate and residual effects of a four-night sleep extension intervention (10 hours time in bed) in this population. Consented participants wore a wrist actigraph for fifteen nights in order to measure sleep duration and a cognitive motor battery was conducted after seven nights of habitual sleep (Day 8 – pre-test), after the four nights of sleep extension intervention (Day 12 – post-test), and after the resumption of habitual sleep for four nights (Day 16 – follow-up). Between group comparisons of mean pre- to post-test score changes and mean pre-test to follow-up score changes were performed using independent sample t-tests. Results revealed that the sleep extension group significantly increased their mean sleep duration over the intervention period and that the four nights of sleep extension resulted in immediate benefits in alertness, psychomotor vigilance/attention, executive function performance, standing broad jump performance, and motivation levels. Benefits of sleep extension on broad jump performance and motivation level were still evident four days after resumption of habitual sleep schedules. These results suggest that sleep extension enhances both cognitive and motor performance in college tactical athletes, with some performance benefits lasting days after returning to habitual sleep patterns. Considering the performance improvements noted following sleep extension, a four-night intervention should be considered for training programs aiming to enhance overall performance

The functional neuroanatomy of auditory sensory gating and its behavioural implications

Auditory sensory gating (ASG) is the ability in individuals to suppress incoming irrelevant sensory input, indexed by evoked response to paired auditory stimuli. ASG is impaired in psychopathology such as schizophrenia, in which it has been proposed as putative endophenotype. This study aims to characterise electrophysiological properties of the phenomenon using MEG in time and frequency domains as well as to localise putative networks involved in the process at both sensor and source level. We also investigated the relationship between ASG measures and personality profiles in healthy participants in the light of its candidate endophenotype role in psychiatric disorders. Auditory evoked magnetic fields were recorded in twenty seven healthy participants by P50 ‘paired-click’ paradigm presented in pairs (conditioning stimulus S1- testing stimulus S2) at 80dB, separated by 250msec with inter trial interval of 7-10 seconds. Gating ratio in healthy adults ranged from 0.5 to 0.8 suggesting dimensional nature of P50 ASG. The brain regions active during this process were bilateral superior temporal gyrus (STG) and bilateral inferior frontal gyrus (IFG); activation was significantly stronger in IFG during S2 as compared to S1 (at p<0.05). Measures of effective connectivity between these regions using DCM modelling revealed the role of frontal cortex in modulating ASG as suggested by intracranial studies, indicating major role of inhibitory interneuron connections. Findings from this study identified a unique event-related oscillatory pattern for P50 ASG with alpha (STG)-beta (IFG) desynchronization and increase in cortical oscillatory gamma power (IFG) during S2 condition as compared to S1. These findings show that the main generator for P50 response is within temporal lobe and that inhibitory interneurons and gamma oscillations in the frontal cortex contributes substantially towards sensory gating. Our findings also show that ASG is a predictor of personality profiles (introvert vs extrovert dimension)

Abnormal Beta and Gamma Frequency Neural Oscillations Mediate Auditory Gating in Schizophrenia

Sensory gating is a process in which the brain’s response to irrelevant and repetitive stimuli is inhibited. Poor P50 gating in those with schizophrenia is typically measured by the ratio or difference score of the event-related potential (ERP) amplitudes in response to a paired click paradigm. Failure to suppress the ERP in response to the second click is thought to reflect a faulty inhibitory system. Oscillatory activity during the inter-click interval in the beta (20-30 Hz) and gamma (30-50 Hz) frequency bands may reflect inhibitory processes initiated by the first click. Paired-auditory stimuli were presented to 131 participants with schizophrenia and 196 healthy controls. P50 ERP amplitude as well as averaged- and single-trial beta (20-30 Hz) and gamma (30-50 Hz) frequency power during the inter-click interval were measured from the CZ electrode site. Data were analyzed using a series of ANOVAs and regression models. The statistical analyses provide evidence that patients with schizophrenia exhibited less evoked beta and gamma power across the delay interval, particularly at the 0-100 ms time point, in response to S1. We found that evoked beta and gamma responses early during the 500 ms delay interval (0-100 ms) are critical in determining the S1 amplitude and extent of P50 gating across the delay interval for both healthy controls and individuals with schizophrenia. Our findings also support a disruption in “gating in” processes in those with schizophrenia. The investigation of oscillatory activity at different time points during the inter-click interval may provide a new framework for studying the mechanisms that support sensory inhibition, and may help researchers and clinicians develop future cognitive training protocols