Lateralization of CA1 assemblies in the absence of CA3 input

AbstractIn the hippocampal circuit CA3 input plays a critical role in the organization of CA1 population activity, both during learning and sleep. While integrated spatial representations have been observed across the two hemispheres of CA1, these regions lack direct connectivity and thus the circuitry responsible remains largely unexplored. Here we investigate the role of CA3 in organizing bilateral CA1 activity by blocking synaptic transmission at CA3 terminals through the inducible transgenic expression of tetanus toxin. Although the properties of single place cells in CA1 were comparable bilaterally, we find a decrease of ripple synchronization between left and right CA1 after silencing CA3. Further, during both exploration and rest, CA1 neuronal ensemble activity is less coordinated across hemispheres. This included degradation of the replay of previously explored spatial paths in CA1 during rest, consistent with the idea that CA3 bilateral projections integrate activity between left and right hemispheres and orchestrate bilateral hippocampal coding.

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Bias for the Left Visual Field in Rapid Serial Visual Presentation: Effects of Additional Salient Cues Suggest a Critical Role of Attention

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00714 ◽

2015 ◽

Vol 27 (2) ◽

pp. 266-279 ◽

Cited By ~ 18

Author(s):

Kamila Śmigasiewicz ◽

Dariusz Asanowicz ◽

Nicole Westphal ◽

Rolf Verleger

Keyword(s):

Visual Field ◽

Left Visual Field ◽

Right Hemisphere ◽

Critical Role ◽

Visual Presentation ◽

The Other ◽

Early Posterior Negativity ◽

Left And Right ◽

The Right

Everyday experience suggests that people are equally aware of stimuli in both hemifields. However, when two streams of stimuli are rapidly presented left and right, the second target (T2) is better identified in the left hemifield than in the right hemifield. This left visual field (LVF) advantage may result from differences between hemifields in attracting attention. Therefore, we introduced a visual cue shortly before T2 onset to draw attention to one stream. Thus, to identify T2, attention was correctly positioned with valid cues but had to be redirected to the other stream with invalid ones. If the LVF advantage is caused by differences between hemifields in attracting attention, invalid cues should increase, and valid cues should reduce the LVF advantage as compared with neutral cues. This prediction was confirmed. ERP analysis revealed that cues evoked an early posterior negativity, confirming that attention was attracted by the cue. This negativity was earlier with cues in the LVF, which suggests that responses to salient events are faster in the right hemisphere than in the left hemisphere. Valid cues speeded up, and invalid cues delayed T2-evoked N2pc; in addition, valid cues enlarged T2-evoked P3. After N2pc, right-side T2 evoked more sustained contralateral negativity than left T2, least long-lasting after valid cues. Difficulties in identifying invalidly cued right T2 were reflected in prematurely ending P3 waveforms. Overall, these data provide evidence that the LVF advantage is because of different abilities of the hemispheres in shifting attention to relevant events in their contralateral hemifield.

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DUAL-tDCS Treatment over the Temporo-Parietal Cortex Enhances Writing Skills: First Evidence from Chronic Post-Stroke Aphasia

Life ◽

10.3390/life11040343 ◽

2021 ◽

Vol 11 (4) ◽

pp. 343

Author(s):

Francesca Pisano ◽

Carlo Caltagirone ◽

Chiara Incoccia ◽

Paola Marangolo

Keyword(s):

Parietal Cortex ◽

Critical Role ◽

Writing Skills ◽

Double Blind ◽

Post Stroke ◽

Lexical Route ◽

Left And Right ◽

Cathodal Current ◽

First Time

The learning of writing skills involves the re-engagement of previously established independent procedures. Indeed, the writing deficit an adult may acquire after left hemispheric brain injury is caused by either an impairment to the lexical route, which processes words as a whole, to the sublexical procedure based on phoneme-to-grapheme conversion rules, or to both procedures. To date, several approaches have been proposed for writing disorders, among which, interventions aimed at restoring the sub-lexical procedure were successful in cases of severe agraphia. In a randomized double-blind crossover design, fourteen chronic Italian post-stroke aphasics underwent dual transcranial direct current stimulation (tDCS) (20 min, 2 mA) with anodal and cathodal current simultaneously placed over the left and right temporo-parietal cortex, respectively. Two different conditions were considered: (1) real, and (2) sham, while performing a writing task. Each experimental condition was performed for ten workdays over two weeks. After real stimulation, a greater amelioration in writing with respect to the sham was found. Relevantly, these effects generalized to different language tasks not directly treated. This evidence suggests, for the first time, that dual tDCS associated with training is efficacious for severe agraphia. Our results confirm the critical role of the temporo-parietal cortex in writing skills.

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Cortical ensemble activity discriminates auditory attentional states

10.1101/622332 ◽

2019 ◽

Author(s):

Pan-tong Yao ◽

Jia Shen ◽

Liang Chen ◽

Shaoyu Ge ◽

Qiaojie Xiong

Keyword(s):

Cortical Activity ◽

Task Engagement ◽

Auditory Stimuli ◽

Neuronal Responses ◽

Population Activity ◽

Passive Condition ◽

Neuronal Ensemble ◽

Passive Hearing ◽

Cortical Representations ◽

Ensemble Activity

AbstractSelective attention modulates sensory cortical activity. It remains unclear how auditory cortical activity represents stimuli that differ behaviorally. We designed a cross-modality task in which mice made decisions to obtain rewards based on attended visual or auditory stimuli. We recorded auditory cortical activity in behaving mice attending to, ignoring, or passively hearing auditory stimuli. Engaging in the task bidirectionally modulates neuronal responses to the auditory stimuli in both the attended and ignored conditions compared to passive hearing. Neuronal ensemble activity in response to stimuli under attended, ignored and passive conditions are readily distinguishable. Furthermore, ensemble activity under attended and ignored conditions are in closer states compared to passive condition, and they share a component of attentional modulation which drives them to the same direction in the population activity space. Our findings suggest that task engagement changes sensory cortical representations across modalities in the same directions, and cross-modality attention may differentially modulates attended and ignored modalities.

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Cortical ensemble activity discriminates auditory attentional states

Molecular Brain ◽

10.1186/s13041-019-0502-z ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Pan-tong Yao ◽

Jia Shen ◽

Liang Chen ◽

Shaoyu Ge ◽

Qiaojie Xiong

Keyword(s):

Sensory Processing ◽

Cortical Activity ◽

Activity Space ◽

Auditory Stimuli ◽

Neuronal Responses ◽

Population Activity ◽

Passive Condition ◽

Neuronal Ensemble ◽

Passive Hearing ◽

Ensemble Activity

Abstract Selective attention modulates sensory cortical activity. It remains unclear how auditory cortical activity represents stimuli that differ behaviorally. We designed a cross-modality task in which mice made decisions to obtain rewards based on attended visual or auditory stimuli. We recorded auditory cortical activity in behaving mice attending to, ignoring, or passively hearing auditory stimuli. Engaging in the task bidirectionally modulates neuronal responses to the auditory stimuli in both the attended and ignored conditions compared to passive hearing. Neuronal ensemble activity in response to stimuli under attended, ignored and passive conditions are readily distinguishable. Furthermore, ensemble activity under attended and ignored conditions are in closer states compared to passive condition, and they share a component of attentional modulation which drives them to the same direction in the population activity space. Our findings suggest that the ignored condition is very different from the passive condition, and the auditory cortical sensory processing under ignored, attended and passive conditions are modulated differently.

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The Continuity of Context: A Role for the Hippocampus

10.31234/osf.io/ushka ◽

2020 ◽

Author(s):

Andrew Maurer ◽

Lynn Nadel

Keyword(s):

Stimulus Equivalence ◽

Multiple Scales ◽

Critical Role ◽

Longitudinal Axis ◽

Place Cells ◽

Pattern Separation ◽

Anatomy And Physiology ◽

The Brain ◽

Over Time

Tracking moment-to-moment change in input, and detecting change sufficient to require altering behavior is crucial to survival. We discuss how the brain evaluates change over time, focusing on hippocampus and its role in tracking context. We leverage the anatomy and physiology of the hippocampal longitudinal axis, re-entrant loops, and amorphous networks, to account for stimulus equivalence and the updating of an organism’s sense of its context. Place cells play a central role in tracking contextual continuities and discontinuities across multiple scales, a capacity beyond current models of pattern separation and completion. This perspective highlights the critical role of the hippocampus in both spatial cognition and episodic memory: tracking change and detecting boundaries separating one context, or episode, from another.

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The Role of the SLP in Autism Spectrum Disorder Screening and Assessment

Perspectives on Language Learning and Education ◽

10.1044/lle15.2.50 ◽

2008 ◽

Vol 15 (2) ◽

pp. 50-59 ◽

Cited By ~ 1

Author(s):

Amy Philofsky

Keyword(s):

Language Development ◽

Critical Role ◽

Children With Autism ◽

Autism Spectrum ◽

Children With Asd ◽

Prevalence Estimates ◽

Notable Increase ◽

Screening Assessment ◽

Critical Components

AbstractRecent prevalence estimates for autism have been alarming as a function of the notable increase. Speech-language pathologists play a critical role in screening, assessment and intervention for children with autism. This article reviews signs that may be indicative of autism at different stages of language development, and discusses the importance of several psychometric properties—sensitivity and specificity—in utilizing screening measures for children with autism. Critical components of assessment for children with autism are reviewed. This article concludes with examples of intervention targets for children with ASD at various levels of language development.

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