DOCSLIB.ORG

Sensory Gating in Patients with Alzheimer's Disease and Their Biological Children

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sensory Gating in Patients with Alzheimer's Disease and Their Biological Children Current Topics in Research American Journal of Alzheimer’s Disease & Other Dementias® Volume 21 Number 6 December 2006/January 2007 439-447 Sensory Gating in Patients With © 2007 Sage Publications 10.1177/1533317506292282 http://ajadd.sagepub.com Alzheimer’s Disease and Their hosted at Biological Children http://online.sagepub.com Brandon A. Ally, PhD, Gary E. Jones, PhD, Jack A. Cole, PhD, and Andrew E. Budson, MD Research has shown that sensory gating is largely mod- potentials were recorded from 4 groups of 20 subjects ualted by acetylcholine. Diminished levels of acetyl- per group (AD, older controls, FH+, FH–). The results choline and sensory gating deficits have been reported showed that while the AD group demonstrated sensory in research involving Alzheimer’s disease (AD) patients. gating abnormalities, the FH+ group did not when However, there has been little investigation into those compared to their peers with no family history of the with a family history (FH+) of AD. The rationale of this disease (FH–). These results are discussed in relation study was to determine whether sensory gating impair- to previous findings reporting P300 abnormalities in ments could distinguish those with early AD from the FH+ group. individuals with increased risk for the disease while replicating previous findings of gating abnormalities in Keywords: Alzheimer’s disease; sensory gating; P50; AD patients. Using the paried-click paradigm, evoked at risk lzheimer’s disease (AD) is becoming highly 25 years. Finding preclinical markers and additional prevalent in the increasingly aged population risk factors of AD can prospectively lead to a more of the United States, affecting nearly 4.5 mil- accurate identification of individuals who will ulti- A 1 lion Americans annually. AD is a progressive form of mately develop the disease, allowing treatments to dementia that affects parts of the brain that control be initiated earlier and helping to reduce the near memory, language, and executive abilities, and it is $100 billion annual cost to care for patients with the most commonly diagnosed form of dementia. AD.2 Currently, treatments are being developed to Because of the devastating impact of AD on patients treat the underlying pathology of AD.3,4 Current and caregivers’ lives and on the infrastructure of the thinking is that pathology may be present 10 to 15 health care system, the clinical characteristics, pathol- years before clinical presentation or diagnosis,5 and ogy, and risk factors associated with this disease finding preclinical markers of the disease is of para- have received well-deserved attention over the past mount importance. AD is characterized by neuritic plaques, neurofib- rillary tangles, and a presynaptic deficit in acetyl- From Edith Nourse Rogers Memorial Veteran’s Hospital, GRECC, choline.6 Furthermore, it has been reported that Bedford, Massachusetts (BAA, AEB); Boston University School of Medicine, Department of Neurology, Cognitive Neuro- patients with AD show disrupted basal forebrain science Division of the Alzheimer’s Disease Center (BAA, AEB); cholinergic pathways,7 and some patients reveal Department of Psychology, Louisiana State University at associated alpha-7 receptor loss.8 This cholinergic Shreveport (GEJ); and Danville VA Medical Center, Danville, Illinois (JAC). dysfunction has been linked to behavioral distur- bances6 and cognitive deficits such as attention and Dr Budson’s work on this project was supported by National 9,10 Institute on Aging grant P30 AG13846. working memory impairments. Studies examining the efficacy of cholinesterase inhibitor therapy in Address correspondence to: Brandon A. Ally, PhD, Bedford VAMC, GRECC, Building 62, Room B31-A, 200 Springs Road, patients with AD suggest that behavioral distur- Bedford, MA 01730 (e-mail: [email protected]). bances such as distractibility, agitation, hallucinations, 439 440 American Journal of Alzheimer’s Disease & Other Dementias® / Vol. 21, No. 6, December 2006/January 2007 delusions, overactivity, and anxiety can be reduced phase subserved by the temporoparietal and pre- when taking the medication.11-13 frontal cortex and a later phase mediated by the Research examining patients in the preclinical hippocampus. and early stages of AD suggest that cytopathological In research paradigms, sensory gating is exam- changes occur in one of the brain’s largest choliner- ined using the auditory paired-click paradigm, also gic centers, the nucleus basalis.14 However, it is cur- known as the conditioning-test paradigm. P50 dif- rently unknown at what point in the disease process ferences are assessed by measuring the amplitude of this cytopathology takes place. Mesulam and col- the P50 potential to the test click (second click) as leagues14 suggest that although the number of cholin- compared to the conditioning click (first click) of a ergic neurons in the nucleus basalis of patients with paired-click paradigm. Researchers then typically mild cognitive impairment (MCI) is not reduced produce a ratio called the sensory gating ratio by when compared to age-matched controls, these neu- dividing the test click amplitude by the conditioning rons are at pretangle stages of cytopathology and are click amplitude (click 2/click 1).22 Responses to the unlikely to function normally. Mesulam et al further conditioning click can also be compared to ensure suggest that early neurofibrillary tangle formations that any deficit in sensory gating is not due to some have been shown to interfere with protein synthesis nonspecific changes in the brain that affect sensory- and energy metabolism and that normal whole-brain evoked responses. In effect, the conditioning click acetylcholine levels do not ensure the integrity of can act as an internal control measure for between- cholinergic innervation of the cortex. Because the group comparisons. nucleus basalis is known to be the main source of Data suggest that P50 sensory gating heavily acetylcholine to the cortex, cytopathology in a single involves the cholinergic system.16,21,23,24 Leonard et al24 nucleus basalis neuron may have widespread conse- proposed that interneurons and pyramidal neurons quences on cortical cholinergic innervation.14 There receive cholinergic input from the septum (which is has been recent evidence supporting the idea that connected to important structures involved in AD cholinergic cells are dysfunctional in MCI and early such as the hippocampus and fornix) and that the stages of the disease. A positron emission tomo- blockade of the septal cholinergic input removes graphy (PET) study completed by Herholz et al15 the inhibitory effect of the interneurons, allowing showed a significant reduction in cerebral acetyl- pyramidal cells to fire in response to irrelevant cholinesterase in the brains of patients with MCI. repetitive stimuli. Freedman et al25 support this find- Neurophysiologists have studied cholinergic func- ing by reporting that the cholinergic agonist nicotine tion using the exogenously evoked auditory P50 improves gating in individuals who exhibit the P50 component.16 P50 has been used to examine the gating deficit, whereas antagonists of the α-7 nico- ability of the brain to inhibit irrelevant sensory input tinic receptor block P50 inhibition, impairing gat- in a wide range of healthy and neurologically impaired ing. Furthermore, several studies have examined the populations.17 The term sensory gating, commonly direct link between P50 and scopolamine, which associated with the P50 component, refers to the temporarily blocks muscarinic cholinergic receptors inhibition of a stimulus-related neuronal response if in the brain. Results of these studies also suggest the stimulus is preceded by a warning stimulus.18 that these cholinergic receptors modulate P50, and Studies have demonstrated that the habituation of they have reported that cholinergic contribution to repetitive, irrelevant sensory stimuli is an essential preattentive auditory processing underlies stimulus- function of the human brain that keeps higher cor- change detection.16,23,26,27 tical centers from being flooded with this sensory Studies investigating the P50 component in the information.17 Disruption in this sensory gating process AD/MCI process have found a diminished ability to could impair the brain’s ability to select, process, gate irrelevant repetitive stimuli. Most research and store important information or stimuli.19 Animal examining patients with AD has found disrupted studies20 and postmortem studies of patients with sensory gating.18,26,28,29 Jessen and colleagues18 con- schizophrenia21 reveal that sensory gating may be cluded that disturbed sensory gating in patients with mediated by the α-7 subunit of the cholinergic nico- AD results from cholinergic dysfunction and possi- tinic receptor. Grunwald et al17 identified the neural bly from α-7 nicotinic receptor loss. One study, correlates of the gating process, reporting that sen- however, found no significant differences in P50 sory gating may be a multistep process, with an early ratios between patients with AD and an age-matched Sensory Gating and Alzheimer’s Disease / Ally et al 441 control group.30 Investigations into the early stages services, contained individuals with a National of cognitive impairment linked to AD have also found Institute of Neurological and Communicative Diseases– sensory gating deficits in patients with MCI.31,32 Alzheimer’s Disease and Related Disorders Association Irimajiri et al32 suggest that changes in the cholinergic diagnosis
Load more

Recommended publications
  • Self-Reported Sensory Gating and Stress-Related Hypertension
    Henry Ford Health System Henry Ford Health System Scholarly Commons Public Health Sciences Articles Public Health Sciences 9-1-2020 Self-Reported Sensory Gating and Stress-Related Hypertension Rosalind M. Peters Maher El-Masri Andrea E. Cassidy-Bushrow Follow this and additional works at: https://scholarlycommons.henryford.com/ publichealthsciences_articles Self-Reported Sensory Gating and Stress-Related Hypertension Rosalind M. Peters ▼ Maher El-Masri ▼ Andrea E. Cassidy-Bushrow Background: Increasing evidence views hypertension as a stress-induced disorder. Stressors must be “gated” by the brain before any inflammatory or immune processes that contribute to hypertension are initiated. No studies were found that examined sensory gating in relation to hypertension. Objectives: The aim of the study was to determine if disturbances in self-reported sensory gating could differentiate normotensive from hypertensive young adults. Methods: A nonmatched, case–control design was used. We administered an online survey to 163 young adult participants. Participants were predominantly female, in their mid-20s, well educated, and approximately evenly distributed by race and hypertension status. The Sensory Gating Inventory (SGI) measured gating disturbances. Results: The mean SGI scores were significantly higher among persons diagnosed with hypertension, reflecting a moderate effect size of sensory gating. After adjusting for confounders, however, the normotensive and hypertensive groups were not significantly different on their SGI scores. Discussion: With an observed moderate effect size of 0.35, but low power, more research is warranted regarding the role of gating disturbances in the development of stress-induced hypertension. Clinically, the SGI may be important for screening patients who would benefit from ambulatory blood pressure monitoring to identify persons with masked hypertension.
    [Show full text]
  • Auditory Gating Processes and Binaural Inhibition in the Inferior Colliculus
    Hearing Research 168 (2002) 98^109 www.elsevier.com/locate/heares Review Auditory gating processes and binaural inhibition in the inferior colliculus Liang Li Ã, Qi Yue Department of Psychology, Peking University, Beijing 100871, PR China Received 28 June 2001;accepted 15 January 2002 Abstract Physiological/behavioral/perceptual responses to an auditory stimulus can be inhibited by another leading auditory stimulus at certain stimulus intervals, and have been considered useful models of auditory gating processes. Two typical examples of auditory gating are prepulse inhibition of the startle reflex and the precedence effect (echo suppression). This review summarizes studies of these two auditory gating processes with regard to their biological significance, cognitive modulation, binaural properties, and underlying neural mechanisms. Both prepulse inhibition and the precedence effect have gating functions of reducing the disruptive influence of the lagging sound, but prepulse inhibition has a much longer temporal window than the precedence effect. Attentional processes can modulate prepulse inhibition, and the listener’s previous experience can modulate the precedence effect. Compared to monaural hearing, binaural hearing reduces prepulse inhibition but enhances the precedence effect. The inferior colliculus, the major structure of the auditory midbrain, plays an important role in mediating these two auditory gating processes, and inhibitory neural transmissions within the inferior colliculus may account for binaural inhibition observed in prepulse inhibition and lag suppression recorded in the inferior colliculus. The neural mechanisms underlying binaural inhibition in the inferior colliculus are also discussed. ß 2002 Elsevier Science B.V. All rights reserved. Key words: Auditory gating;Prepulse inhibition;Precedence e¡ect;Binaural inhibition;Inferior colliculus;Inhibitory trans- mission 1.
    [Show full text]
  • Sensory Gating Endophenotype Based on Its Neural Oscillatory Pattern and Heritability Estimate
    ORIGINAL ARTICLE Sensory Gating Endophenotype Based on Its Neural Oscillatory Pattern and Heritability Estimate L. Elliot Hong, MD; Ann Summerfelt, BS; Braxton D. Mitchell, PhD; Robert P. McMahon, PhD; Ikwunga Wonodi, MD; Robert W. Buchanan, MD; Gunvant K. Thaker, MD Context: The auditory sensory gating deficit has been con- first-degree relatives (n=74), and control participants from sidered a leading endophenotype in schizophrenia. How- the community (n=70). ever, the commonly used index of sensory gating, P50, has low heritability in families of people with schizophrenia, Main Outcome Measures: Gating of frequency- raising questions about its utility in genetic studies. We hy- specific oscillatory responses, gating of the P50 wave, and pothesized that the sensory gating deficit may occur in a their heritability estimates. specific neuronal oscillatory frequency that reflects the un- derlying biological process of sensory gating. Frequency- Results: Gating of the ␪-␣–band responses of the con- specific sensory gating may be less complex than the P50 trol participants were significantly different from those response, and therefore closer to the direct genetic effects, with schizophrenia (PϽ.001) and their first-degree and thus a more valid endophenotype. relatives (P=.04 to .009). The heritability of ␪-␣–band gating was estimated to be between 0.49 and 0.83 and Objectives: To compare the gating of frequency- was at least 4-fold higher than the P50 heritability esti- specific oscillatory responses with the gating of P50 and mate. to compare their heritabilities. Conclusions: Gatingofthe␪-␣–frequency oscillatory sig- Design: We explored single trial–based oscillatory gat- nal in the paired-click paradigm is more strongly asso- ing responses in people with schizophrenia, their rela- ciated with schizophrenia and has significantly higher tives, and control participants from the community.
    [Show full text]
  • Abnormal Sleep Spindles, Memory Consolidation, and Schizophrenia
    CP15CH18_Manoach ARjats.cls April 17, 2019 13:18 Annual Review of Clinical Psychology Abnormal Sleep Spindles, Memory Consolidation, and Schizophrenia Dara S. Manoach1,2 and Robert Stickgold3 1Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA; email: [email protected] 2Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA 3Department of Psychiatry, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215; email: [email protected] Annu. Rev. Clin. Psychol. 2019. 15:451–79 Keywords First published as a Review in Advance on cognition, endophenotype, genetics, memory, schizophrenia, sleep, spindles February 20, 2019 The Annual Review of Clinical Psychology is online at Abstract clinpsy.annualreviews.org There is overwhelming evidence that sleep is crucial for memory consol- https://doi.org/10.1146/annurev-clinpsy-050718- idation. Patients with schizophrenia and their unaffected relatives have a 095754 specific deficit in sleep spindles, a defining oscillation of non-rapid eye Access provided by 73.61.23.229 on 05/29/19. For personal use only. Copyright © 2019 by Annual Reviews. movement (NREM) Stage 2 sleep that, in coordination with other NREM All rights reserved oscillations, mediate memory consolidation. In schizophrenia, the spindle Annu. Rev. Clin. Psychol. 2019.15:451-479. Downloaded from www.annualreviews.org deficit correlates with impaired sleep-dependent memory consolidation, positive symptoms, and abnormal thalamocortical connectivity. These re- lations point to dysfunction of the thalamic reticular nucleus (TRN), which generates spindles, gates the relay of sensory information to the cortex, and modulates thalamocortical communication.
    [Show full text]
  • Intrinsic Sensory Disinhibition Contributes to Intrusive Re-Experiencing in Combat Veterans
    www.nature.com/scientificreports OPEN Intrinsic sensory disinhibition contributes to intrusive re- experiencing in combat veterans Kevin J. Clancy *, Alejandro Albizu, Norman B. Schmidt & Wen Li* Intrusive re-experiencing of traumatic events is a hallmark symptom of posttraumatic stress disorder, characterized by rich and vivid sensory details as reported in “fashbacks”. While prevailing models of trauma intrusions focus on dysregulated emotional processes, we hypothesize that a defciency in intrinsic sensory inhibition could drive overactivation of sensory representations of trauma memories, precipitating sensory-rich intrusions. In a sample of combat veterans, we examined resting-state alpha (8–12 Hz) oscillatory activity (in both power and posterior→frontal connectivity), given its role in sensory cortical inhibition, in association with intrusive re-experiencing symptoms. Veterans further participated in an odor task (including both combat and non-combat odors) to assess olfactory trauma memory and emotional response. We observed an association between intrusive re-experiencing symptoms and attenuated resting-state posterior→frontal alpha connectivity, which were both correlated with olfactory trauma memory. Importantly, olfactory trauma memory was identifed as a mediator of the relationship between alpha connectivity and intrusive re-experiencing, suggesting that defcits in intrinsic sensory inhibition contributed to intrusive re-experiencing of trauma via heightened trauma memory. Therefore, by permitting unfltered sensory cues
    [Show full text]
  • MDMA): Relevance to Schizophrenia
    brain sciences Article Pharmacological Mechanisms Involved in Sensory Gating Disruption Induced by (±)-3,4-Methylene- Dioxymethamphetamine (MDMA): Relevance to Schizophrenia Jaime Lee 1, Shane Thwaites 1, Andrea Gogos 1 and Maarten van den Buuse 1,2,* 1 Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne 3010, Australia; a.gogos@florey.edu.au 2 School of Psychology and Public Health, La Trobe University, Melbourne 3086, Australia * Correspondence: [email protected]; Tel.: +61-394-795-257 Received: 6 November 2019; Accepted: 10 January 2020; Published: 13 January 2020 Abstract: Sensory gating deficits have been demonstrated in schizophrenia, but the mechanisms involved remain unclear. In the present study, we used disruption of paired-pulse gating of evoked potentials in rats by the administration of ( )-3,4-methylene-dioxymethamphetamine (MDMA) to ± study serotonergic and dopaminergic mechanisms involved in auditory sensory gating deficits. Male Sprague-Dawley rats were instrumented with cortical surface electrodes to record evoked potential changes in response to pairs of 85dB tones (S1 and S2), 500msec apart. Administration of MDMA eliminated the normal reduction in the amplitude of S2 compared to S1, representing disruption of auditory sensory gating. Pretreatment of the animals with the dopamine D1 receptor antagonist, SCH23390, the dopamine D2 receptor antagonist, haloperidol, the serotonin (5-HT)1A receptor antagonist, WAY100635, or the 5-HT2A receptor antagonist, ketanserin, all blocked the effect of MDMA, although the drugs differentially affected the individual S1 and S2 amplitudes. These data show involvement of both dopaminergic and serotonergic mechanisms in disruption of auditory sensory gating by MDMA. These and previous results suggest that MDMA targets serotonergic pathways, involving both 5-HT1A and 5-HT2A receptors, leading to dopaminergic activation, involving both D1 and D2 receptors, and ultimately sensory gating deficits.
    [Show full text]
  • Large-Scale Networks for Auditory Sensory Gating in the Awake Mouse
    New Research Sensory and Motor Systems Large-Scale Networks for Auditory Sensory Gating in the Awake Mouse ء ء Abbas Khani,1 Florian Lanz,1 Gerard Loquet,2 Karl Schaller,3 Christoph Michel,1,4 and Charles Quairiaux1 https://doi.org/10.1523/ENEURO.0207-19.2019 1Functional Brain Mapping Lab., Department of Basic Neurosciences, University of Geneva, CH-1211 Geneva, Switzerland, 2Department of Clinical Medicine, Aalborg University, 9000 Aalborg, Denmark, 3Division of Neurosurgery, University Hospitals of Geneva, University of Geneva, CH-1211 Geneva, Switzerland, 4Centre for Biomedical Imaging (CIBM), CH-1015 Lausanne, Switzerland Abstract 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.
    [Show full text]
  • Comparing Pharmacological Modulation of Sensory Gating in Healthy Humans and Rats: the Effects of Reboxetine and Haloperidol
    Neuropsychopharmacology (2016) 41, 638–645 © 2016 American College of Neuropsychopharmacology. All rights reserved 0893-133X/16 www.neuropsychopharmacology.org Comparing Pharmacological Modulation of Sensory Gating in Healthy Humans and Rats: The Effects of Reboxetine and Haloperidol *,1,2 1 2 3 4 Louise Witten , Jesper Frank Bastlund , Birte Y Glenthøj , Christoffer Bundgaard , Björn Steiniger-Brach , 1 2,5 Arne Mørk and Bob Oranje 1Synaptic Transmission 1, H. Lundbeck A/S, Valby, Denmark; 2Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS). Center for Neuropsychiatric Schizophrenia Research (CNSR), Copenhagen University Hospital, Psychiatric Center Glostrup, Glostrup, Denmark; 3 4 Discovery DMPK, H. Lundbeck A/S, Copenhagen-Valby, Denmark; Medical Affairs-Addiction Disorders, H. Lundbeck A/S, Valby, Denmark; 5 Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands Sensory gating is the brain’s ability to filter out irrelevant information before it reaches high levels of conscious processing. In the current study we aimed to investigate the involvement of the noradrenergic and dopaminergic neurotransmitter systems in sensory gating. Furthermore, we investigated cross-species reliability by comparing effects in both healthy humans and rats, while keeping all experimental = conditions as similar as possible between the species. The design of the human experiment (n 21) was a double-blind, placebo- controlled, cross-over study where sensory gating was assessed following a dose of either reboxetine (8 mg), haloperidol (2 mg), their combination or placebo at four separate visits. Similarly in the animal experiment sensory gating was assessed in rats, (n = 22) following a dose of reboxetine (2 mg/kg), haloperidol (0.08 mg/kg), their combination or placebo.
    [Show full text]
  • Restless 'Rest': Intrinsic Sensory Hyperactivity and Disinhibition in Post-Traumatic Stress Disorder
    doi:10.1093/brain/awx116 BRAIN 2017: Page 1 of 10 | 1 Restless ‘rest’: intrinsic sensory hyperactivity and disinhibition in post-traumatic stress disorder Kevin Clancy,1 Mingzhou Ding,2 Edward Bernat,3 Norman B. Schmidt1 and Wen Li1 Post-traumatic stress disorder is characterized by exaggerated threat response, and theoretical accounts to date have focused on impaired threat processing and dysregulated prefrontal-cortex-amygdala circuitry. Nevertheless, evidence is accruing for broad, threat-neutral sensory hyperactivity in post-traumatic stress disorder. As low-level, sensory processing impacts higher-order oper- ations, such sensory anomalies can contribute to widespread dysfunctions, presenting an additional aetiological mechanism for post-traumatic stress disorder. To elucidate a sensory pathology of post-traumatic stress disorder, we examined intrinsic visual cortical activity (based on posterior alpha oscillations) and bottom-up sensory-driven causal connectivity (Granger causality in the alpha band) during a resting state (eyes open) and a passive, serial picture viewing state. Compared to patients with generalized anxiety disorder (n = 24) and healthy control subjects (n = 20), patients with post-traumatic stress disorder (n = 25) demonstrated intrinsic sensory hyperactivity (suppressed posterior alpha power, source-localized to the visual cortex—cuneus and precuneus) and bottom-up inhibition deficits (reduced posterior!frontal Granger causality). As sensory input increased from resting to passive picture viewing, patients with post-traumatic stress disorder failed to demonstrate alpha adaptation, highlighting a rigid, set mode of sensory hyperactivity. Interestingly, patients with post-traumatic stress disorder also showed heightened frontal processing (augmented frontal gamma power, source-localized to the superior frontal gyrus and dorsal cingulate cortex), accompanied by attenuated top–down inhibition (reduced frontal!posterior causality).
    [Show full text]
  • Sensory Gating Deficits, Pattern Completion, and Disturbed Fronto
    Medical Hypotheses (2006) 67, 1173–1184 http://intl.elsevierhealth.com/journals/mehy Sensory gating deficits, pattern completion, and disturbed fronto-limbic balance, a model for description of hallucinations and delusions in schizophrenia Arash Javanbakht * Ibn E Sina Psychiatric Hospital, Mashhad University of Medical Sciences, No. 180 Banafsheh Street, Sajjad Boulevard, Mashhad 91876, Iran Received 21 March 2006; accepted 30 March 2006 Summary Schizophrenia, if not the most difficult, is one of the most difficult mysterious puzzles for psychiatrists, psychologists, and neuroscientists to solve. In this paper, based on the previously known pathologies of schizophrenia, a new model is proposed for explanation of the formation of positive psychotic symptoms of hallucinations and delusions. This model can be used for understanding psychotic or psychotic-like positive symptoms of bipolar mood disorder, posttraumatic stress disorder, obsessive compulsive, and amphetamine and drug-induced psychotic disorders. Based on the postulated model, a spectral view on these disorders with psychotic features is also proposed. These pathologies include auditory sensory gating deficits in hippocampus, abnormal emotional coding in amygdala, pattern completion in thalamic and cortical areas, and disturbed fronto-limbic balance. This model includes anatomical and neurotransmitter defects of hippocampus, amygdala, thalamus, cingula, and prefrontal cortex and their interconnections. A role for hippocampal sensory gating deficits in the pathogenesis of positive psychotic symptoms and interrelation between amygdala and its dopamine level with hippocampus is speculated. This model also hires the interesting function of pattern completion in thalamus and cortical areas for a better explanation of the pathogenesis of hallucinations and delusional psychotic symptoms. Furthermore, there is also explanation for the polygenic etiology of the schizophrenic and psychotic disorders and relation between schizophrenia and bipolar mood disorder in anatomy and neural systems involved.
    [Show full text]
  • Opening the Gate to Working Memory
    Opening the gate to working memory David Badrea,b,1 aDepartment of Cognitive, Linguistic, and Psychological Sciences and bBrown Institute for Brain Science, Brown University, Providence, RI 02912 n a changing and complex world, we of the neurotransmitter dopamine (DA) these “context-dependent” trials, the cue require the ability to sustain pursuit from the ventral tegmental area (VTA) was encoded as a context. I of a goal, while also updating our and substantia nigra (SN) to the PFC. Following this logic, comparison of goals as the need arises. For exam- Thus, DA acts as a gating signal, timing context-dependent vs. context-independent ple, we are capable of rapidly shifting when the PFC accepts new input. In this cues provided a means of testing working- tasks, such as stopping work on a paper to model, the SN/VTA learns when to gate memory updating. First, in fMRI, greater have an involved discussion with a col- from the positive or negative outcomes bilateral DLPFC activation accompanied league. However, we are also able to avoid that follow gating. context-dependent vs. context-independent distracting cues, such as ignoring the un- Several aspects of the DA-updating hy- cues. Next, single-pulse transcranial mag- read e-mail messages incrementing in our pothesis are supported empirically. For netic stimulation (TMS) was applied to inbox while we write. The mechanisms each participant’sDLPFCinalocusthat by which the brain achieves an adaptive ’ showed that participant’s maximal updating balance between flexibility and stability D Ardenne et al. provide effect. When the TMS pulse was applied to remain the basis of much current inves- an important step right DLPFC 150 ms after onset of the cue, tigation in cognitive neuroscience.
    [Show full text]
  • Creativity and Sensory Gating Indexed by the P50: Selective Versus Leaky Sensory Gating in Divergent Thinkers and Creative Achievers
    Neuropsychologia 69 (2015) 77–84 Contents lists available at ScienceDirect Neuropsychologia journal homepage: www.elsevier.com/locate/neuropsychologia Creativity and sensory gating indexed by the P50: Selective versus leaky sensory gating in divergent thinkers and creative achievers Darya L. Zabelina n, Daniel O’Leary, Narun Pornpattananangkul, Robin Nusslock, Mark Beeman Northwestern University, 104 Cresap Hall, 2029 Sheridan Road, Evanston, IL 60208, USA article info abstract Article history: Creativity has previously been linked with atypical attention, but it is not clear what aspects of attention, Received 14 November 2014 or what types of creativity are associated. Here we investigated specific neural markers of a very early Received in revised form form of attention, namely sensory gating, indexed by the P50 ERP, and how it relates to two measures of 20 January 2015 creativity: divergent thinking and real-world creative achievement. Data from 84 participants revealed Accepted 22 January 2015 that divergent thinking (assessed with the Torrance Test of Creative Thinking) was associated with se- Available online 23 January 2015 lective sensory gating, whereas real-world creative achievement was associated with “leaky” sensory Keywords: gating, both in zero-order correlations and when controlling for academic test scores in a regression. Creativity Thus both creativity measures related to sensory gating, but in opposite directions. Additionally, di- Divergent thinking vergent thinking and real-world creative achievement did not interact in predicting P50 sensory gating, Creative achievement suggesting that these two creativity measures orthogonally relate to P50 sensory gating. Finally, the ERP P50 fi – Sensory gating effect was speci c to the P50 neither divergent thinking nor creative achievement were related to later Attention components, such as the N100 and P200.
    [Show full text]