Dynamic causal communication channels between neocortical areas

Dynamic pathways of information flow between distributed brain regions underlie the diversity of behaviour. However, it remains unclear how neuronal activity in one area causally influences ongoing population activity in another, and how such interactions change over time. Here we introduce a causal approach to quantify cortical interactions by pairing simultaneous electrophysiological recordings with neural perturbations. We found that the influence visual cortical areas had on each other was surprisingly variable over time. Both feedforward and feedback pathways reliably affected different subpopulations of target neurons at different moments during processing of a visual stimulus, resulting in dynamically rotating communication dimensions between the two cortical areas. The influence of feedback on primary visual cortex (V1) became even more dynamic when visual stimuli were associated with a reward, impacting different subsets of V1 neurons within tens of milliseconds. This, in turn, controlled the geometry of V1 population activity in a behaviourally relevant manner. Thus, distributed neural populations interact through dynamically reorganizing and context- dependent communication channels to evaluate sensory information.

Representational drift in the mouse visual cortex

10.1101/2020.10.05.327049 ◽

2020 ◽

Cited By ~ 1

Author(s):

Daniel Deitch ◽

Alon Rubin ◽

Yaniv Ziv

Keyword(s):

Large Scale ◽

Activity Patterns ◽

Population Level ◽

Population Activity ◽

Cortical Areas ◽

Electrophysiological Recordings ◽

The Face ◽

Visual Cortical ◽

Mouse Visual Cortex ◽

AbstractNeuronal representations in the hippocampus and related structures gradually change over time despite no changes in the environment or behavior. The extent to which such ‘representational drift’ occurs in sensory cortical areas and whether the hierarchy of information flow across areas affects neural-code stability have remained elusive. Here, we address these questions by analyzing large-scale optical and electrophysiological recordings from six visual cortical areas in behaving mice that were repeatedly presented with the same natural movies. We found representational drift over timescales spanning minutes to days across multiple visual areas. The drift was driven mostly by changes in individual cells’ activity rates, while their tuning changed to a lesser extent. Despite these changes, the structure of relationships between the population activity patterns remained stable and stereotypic, allowing robust maintenance of information over time. Such population-level organization may underlie stable visual perception in the face of continuous changes in neuronal responses.

Feedforward and feedback interactions between visual cortical areas use different population activity patterns

10.1101/2021.02.08.430346 ◽

2021 ◽

Author(s):

João D. Semedo ◽

Anna I. Jasper ◽

Amin Zandvakili ◽

Amir Aschner ◽

Christian K. Machens ◽

...

Keyword(s):

Brain Function ◽

Activity Patterns ◽

Sensory Information ◽

Neuronal Population ◽

Stimulus Onset ◽

Population Activity ◽

Cortical Areas ◽

Visual Areas ◽

Population Interactions ◽

AbstractBrain function relies on the coordination of activity across multiple, recurrently connected, brain areas. For instance, sensory information encoded in early sensory areas is relayed to, and further processed by, higher cortical areas and then fed back. However, the way in which feedforward and feedback signaling interact with one another is incompletely understood. Here we investigate this question by leveraging simultaneous neuronal population recordings in early and midlevel visual areas (V1-V2 and V1-V4). Using a dimensionality reduction approach, we find that population interactions are feedforward-dominated shortly after stimulus onset and feedback-dominated during spontaneous activity. The population activity patterns most correlated across areas were distinct during feedforward- and feedback-dominated periods. These results suggest that feedforward and feedback signaling rely on separate “channels”, such that feedback signaling does not directly affect activity that is fed forward.

Hedonic-Specific Activity in Piriform Cortex During Odor Imagery Mimics That During Odor Perception

Journal of Neurophysiology ◽

10.1152/jn.00349.2007 ◽

2007 ◽

Vol 98 (6) ◽

pp. 3254-3262 ◽

Cited By ~ 92

Author(s):

Moustafa Bensafi ◽

Noam Sobel ◽

Rehan M. Khan

Keyword(s):

Specific Activity ◽

Piriform Cortex ◽

Brain Regions ◽

Specific Pattern ◽

Functional Magnetic Resonance ◽

Resonance Imaging ◽

Odor Perception ◽

Cortical Areas ◽

Visual Cortical ◽

Left Insula

Although it is known that visual imagery is accompanied by activity in visual cortical areas, including primary visual cortex, whether olfactory imagery exists remains controversial. Here we asked whether cue-dependent olfactory imagery was similarly accompanied by activity in olfactory cortex, and in particular whether hedonic-specific patterns of activity evident in olfactory perception would also be present during olfactory imagery. We used functional magnetic resonance imaging to measure activity in subjects who alternated between smelling and imagining pleasant and unpleasant odors. Activity induced by imagining odors mimicked that induced by perceiving real odorants, not only in the particular brain regions activated, but also in its hedonic-specific pattern. For both real and imagined odors, unpleasant stimuli induced greater activity than pleasant stimuli in the left frontal portion of piriform cortex and left insula. These findings combine with findings from other modalities to suggest activation of primary sensory cortical structures during mental imagery of sensory events.

Routing information flow by separate neural synchrony frequencies allows for “functionally labeled lines” in higher primate cortex

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1819827116 ◽

2019 ◽

Vol 116 (25) ◽

pp. 12506-12515 ◽

Cited By ~ 14

Author(s):

Mohammad Bagher Khamechian ◽

Vladislav Kozyrev ◽

Stefan Treue ◽

Moein Esghaei ◽

Mohammad Reza Daliri

Keyword(s):

Information Flow ◽

Information Transfer ◽

Sensory Information ◽

Spike Timing ◽

Oscillatory Activity ◽

Attention Task ◽

Cortical Areas ◽

High Gamma ◽

Ventral Pathway ◽

Efficient transfer of sensory information to higher (motor or associative) areas in primate visual cortical areas is crucial for transforming sensory input into behavioral actions. Dynamically increasing the level of coordination between single neurons has been suggested as an important contributor to this efficiency. We propose that differences between the functional coordination in different visual pathways might be used to unambiguously identify the source of input to the higher areas, ensuring a proper routing of the information flow. Here we determined the level of coordination between neurons in area MT in macaque visual cortex in a visual attention task via the strength of synchronization between the neurons’ spike timing relative to the phase of oscillatory activities in local field potentials. In contrast to reports on the ventral visual pathway, we observed the synchrony of spikes only in the range of high gamma (180 to 220 Hz), rather than gamma (40 to 70 Hz) (as reported previously) to predict the animal’s reaction speed. This supports a mechanistic role of the phase of high-gamma oscillatory activity in dynamically modulating the efficiency of neuronal information transfer. In addition, for inputs to higher cortical areas converging from the dorsal and ventral pathway, the distinct frequency bands of these inputs can be leveraged to preserve the identity of the input source. In this way source-specific oscillatory activity in primate cortex can serve to establish and maintain “functionally labeled lines” for dynamically adjusting cortical information transfer and multiplexing converging sensory signals.

Neural Mechanisms of Spatial Attention in the Visual Thalamus

10.1093/oxfordhb/9780199675111.013.013 ◽

2014 ◽

Cited By ~ 1

Author(s):

Yuri B. Saalmann ◽

Sabine Kastner

Keyword(s):

Selective Attention ◽

Visual Information ◽

Thalamic Nucleus ◽

Sensory Information ◽

Relevant Information ◽

Neural Mechanisms ◽

First Order ◽

Visual Thalamus ◽

Cortical Areas ◽

Neural mechanisms of selective attention route behaviourally relevant information through brain networks for detailed processing. These attention mechanisms are classically viewed as being solely implemented in the cortex, relegating the thalamus to a passive relay of sensory information. However, this passive view of the thalamus is being revised in light of recent studies supporting an important role for the thalamus in selective attention. Evidence suggests that the first-order thalamic nucleus, the lateral geniculate nucleus, regulates the visual information transmitted from the retina to visual cortex, while the higher-order thalamic nucleus, the pulvinar, regulates information transmission between visual cortical areas, according to attentional demands. This chapter discusses how modulation of thalamic responses, switching the response mode of thalamic neurons, and changes in neural synchrony across thalamo-cortical networks contribute to selective attention.

Imaging recent to very remote object-in-place memories in the medial temporal lobe and prefrontal cortex

10.14293/s2199-1006.1.sor-.pp5bcae.v1 ◽

2020 ◽

Author(s):

Erika Atucha ◽

Celia Fuerst ◽

Magdalena Sauvage

Keyword(s):

Memory Retrieval ◽

Medial Temporal Lobe ◽

Brain Regions ◽

Remote Memory ◽

General Mechanism ◽

Cortical Areas ◽

Prefrontal Cortical ◽

Place Task ◽

Cortical Regions ◽

Studies on patient H.M inspired many experiments on the role of the hippocampus and the neocortex in retrieving recent and remote memories. Cortical regions become increasingly engaged for memory retrieval over time, while conflicting results emerge regarding the engagement of the hippocampus, suggested to be ongoing by some or restricted to the retrieval of recent memories by others. In the study of Lux et al, 2016 we tested that this discrepancy might stem from failing to dissociate CA1 from CA3s contribution to memory retrieval over time as CA3 is known to support computations more sensitive to time than CA1. We also reported that parahippocampal cortical areas with tied anatomical connections with the hippocampus were increasingly engaged over time (Lux et al., elife , 2016). This study used a fear conditioning paradigm as emotionally arousing experiences are better remembered than memories devoid of fear content. Here we address whether the differential contribution of brain regions is a general mechanism also subserving memory retrieval devoid of fear content. We succeeded in developing an object-in-place task to investigate remote memory retrieval up to 6 months and the contribution of CA1, CA3, parahippocampal and prefrontal cortical areas to the retrieval of recent versus very remote memories using a high resolution molecular imaging technique based on the detection of the IEG RNA Arc. Preliminary results show that the disengagement of CA3 and persistent engagement of CA1 seem to be a general mechanism in supporting retrieval of remote memory for events.

Pulvinar influences parietal delay activity and information transmission between dorsal and ventral visual cortex in macaques

10.1101/405381 ◽

2018 ◽

Cited By ~ 1

Author(s):

Yuri B. Saalmann ◽

Ryan Ly ◽

Mark A. Pinsk ◽

Sabine Kastner

Keyword(s):

Visual Cortex ◽

Selective Attention ◽

Information Transmission ◽

Parietal Cortex ◽

Sensory Information ◽

Relevant Information ◽

Attention Task ◽

Sustained Activity ◽

Cortical Areas ◽

AbstractThe fronto-parietal attention network represents attentional priorities and provides feedback about these priorities to sensory cortical areas. Sustained spiking activity in the posterior parietal cortex (PPC) carries such prioritized information, but how this activity is sustained in the absence of feedforward sensory information, and how it is transmitted to the ventral visual cortical pathway, is unclear. We hypothesized that the higher-order thalamic nucleus, the pulvinar, which is connected with both the PPC and ventral visual cortical pathway, influences information transmission within and between these cortical regions. To test this, we simultaneously recorded from the pulvinar, lateral intraparietal area (LIP) and visual cortical area V4 in macaques performing a selective attention task. Here we show that LIP influenced V4 during the delay period of the attention task, and that the pulvinar regulated LIP-V4 information exchange. Pulvino-cortical effects were consistent with the pulvinar supporting sustained activity in LIP. Taken together, these results suggest that pulvinar regulation of cortical functional connectivity generalizes to dorsal and ventral visual cortical pathways. Further, the pulvinar’s role in sustaining parietal delay activity during selective attention implicates the pulvinar in other cognitive processes supported by such delay activity, including decision-making, categorization and oculomotor functions.Significance StatementA network of areas on the brain’s surface, in frontal and parietal cortex, allocate attention to behaviorally relevant information around us. Such areas in parietal cortex show sustained activity during maintained attention and transmit behaviorally relevant information to visual cortical areas to enhance sensory processing of attended objects. How this activity is sustained and how it is transmitted to visual areas supporting object perception is unclear. We show that a subcortical area, the pulvinar in the thalamus, helps sustain activity in the cortex and regulates the information transmitted between the fronto-parietal attention network and visual cortex. This suggests that the thalamus, classically considered as a simple relay for sensory information, contributes to higher-level cognitive functions.

Imaging and optogenetically manipulating recent and very remote memories reveals that CA1 is required for retrieving gist memories over time and CA3 for memory precision

10.14293/s2199-1006.1.sor-.ppkjpet.v1 ◽

2020 ◽

Author(s):

Erika Atucha ◽

Shih-pi Ku ◽

Michael Friis Lippert ◽

Frank Walter Ohl ◽

Magdalena Sauvage

Keyword(s):

Memory Retrieval ◽

Contextual Fear Conditioning ◽

Remote Memory ◽

Memory Representation ◽

Contextual Fear ◽

Cortical Areas ◽

Causal Approach ◽

Episodic Memories ◽

Memory Precision ◽

Episodic memories are hippocampus dependent. Over time such memories undergo consolidation and are thought to transition from precise to gist memories and additionally engage neocortical areas. Whether remote memories still depend on the hippocampus remains a controversy that might stem from the difficulties to distinguish activity from CA1 and CA3 subregions in the hippocampus. CA3 is thought to perform computations that are more time sensitive than CA1 such as pattern completion (completion of a full memory representation based on details). Since details fade over time, we predicted that CA3 would no longer contribute to memory retrieval for very remote memory traces. Further, the contribution of parahippocampal cortical areas which tightly interact with the hippocampus is not well understood. We recently published that indeed CA3 plays a time-limited role in the retrieval of memory while CA1 remains engaged for up to 1-year (equivalent to 40-years-old memory in humans) and that parahippocampal cortical areas were increasingly engaged over time. Here we study the contribution of CA1 and CA3 to the nature (gist/precise) of memory retrieval for recent and up to 1-year-old remote memories using a causal approach. We combined optogenetic cell firing inhibition in CA1 and CA3 with a contextual fear conditioning task to investigate memory precision and measured the neuroanatomical correlates using Arc imaging. While CA3 is required for memory precision at recent time points CA1 contributed to retrieving gist memories independently of the age of the memory trace with the support of the parahippocampal areas for the most remote memories.

Engaging regularly with fiction influences connectivity in cortical areas for language and mentalizing

10.31234/osf.io/e7bqj ◽

2017 ◽

Author(s):

Roel M. Willems ◽

Franziska Hartung

Keyword(s):

Functional Connectivity ◽

Time Course ◽

Language Skills ◽

Brain Regions ◽

Brain Areas ◽

Daily Lives ◽

Cortical Areas ◽

Social Abilities ◽

Behavioral Evidence ◽

Amount Of Reading

Behavioral evidence suggests that engaging with fiction is positively correlated with social abilities. The rationale behind this link is that engaging with fictional narratives offers a ‘training modus’ for mentalizing and empathizing. We investigated the influence of the amount of reading that participants report doing in their daily lives, on connections between brain areas while they listened to literary narratives. Participants (N=57) listened to two literary narratives while brain activation was measured with fMRI. We computed time-course correlations between brain regions, and compared the correlation values from listening to narratives to listening to reversed speech. The between-region correlations were then related to the amount of fiction that participants read in their daily lives. Our results show that amount of fiction reading is related to functional connectivity in areas known to be involved in language and mentalizing. This suggests that reading fiction influences social cognition as well as language skills.

Use of masks in public places in Poland during SARS-Cov-2 epidemic: a covert observational study

BMC Public Health ◽

10.1186/s12889-021-10418-3 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Maria Ganczak ◽

Oskar Pasek ◽

Łukasz Duda – Duma ◽

Dawid Świstara ◽

Marcin Korzeń

Keyword(s):

Health Promotion ◽

Observational Study ◽

Control Measure ◽

Communication Channels ◽

Public Spaces ◽

Personal Health ◽

Closed Space ◽

Public Places ◽

Health Control ◽

Abstract Background Face masks have been employed in the COVID-19 pandemic plans as a public and personal health control measure against the spread of SARS-CoV-2. In Poland, obligatory wearing of masks in public spaces was introduced on April 10th, 2020; a relaxation of previous universal measures was announced on May 29th, 2020, limiting use to indoor public places. Objective To assess use of masks or other protective devices in public spaces in Poland during the SARS-Cov-2 epidemic. Methods A non-participatory covert observational study was conducted on three dates, (10.05/18.05/25.05.2020) at public spaces in 13 regions with different risks. Ten consecutive individuals were observed by each of 82 medical students (n = 2460 observations), using a structured checklist. Results Among 2353 observed persons, the female/male ratios were 1.0, 1.1, and 1.0 on the three dates. Almost three quarters - 73.6% (n = 552/750) were using masks on date 1, 66.5% (544/818) on date 2; and 65.7% (516/785) on date 3. Cloth masks predominated on all dates (64.7–62.3%-62.6%), followed by medical (23.4–28.5%-26.9%). Being female (OR = 1.77–1.47-1.53 respectively) and location in a closed space (OR = 2.60–2.59-2.32) were each associated with higher usage. Participants in sports were about two times less likely to use masks (OR = 0.64–0.53-0.53) as compared to other activities. The proportion using masks correctly decreased gradually over time (364/552; 65.9%; 339/544; 62.3% and 304/516; 58.9%). More females wore masks correctly (date 1: 205/294; 69.7% vs 159/258; 61.6%, and date 3: 186/284; 65.5% vs 118/232; 50.9%; p = 0.045; p = 0.0008 respectively). Uncovered noses (47.3–52.7%) and masks around the neck (39.2–42.6%) were the most frequent incorrect practices. Conclusions Practices were not in line with official recommendations, especially among males, and deteriorated over time. Cloth masks were predominantly used in public spaces. Health promotion, through utilizing all available communication channels, would be helpful to increase compliance.