scholarly journals Neural activity in the human anterior thalamus during natural vision

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marcin Leszczynski ◽  
Leila Chaieb ◽  
Tobias Staudigl ◽  
Simon Jonas Enkirch ◽  
Juergen Fell ◽  
...  
Keyword(s):  
Visual Stimulus ◽  
Neural Activity ◽  
Medial Temporal Lobe ◽  
Field Potential ◽  
Stimulus Presentation ◽  
Visual Exploration ◽  
Phase Reset ◽  
Saccade Onset ◽  
Human Thalamus ◽  
Natural Vision

AbstractIn natural vision humans and other primates explore environment by active sensing, using saccadic eye movements to relocate the fovea and sample different bits of information multiple times per second. Saccades induce a phase reset of ongoing neuronal oscillations in primary and higher-order visual cortices and in the medial temporal lobe. As a result, neuron ensembles are shifted to a common state at the time visual input propagates through the system (i.e., just after fixation). The extent of the brain’s circuitry that is modulated by saccades is not yet known. Here, we evaluate the possibility that saccadic phase reset impacts the anterior nuclei of the thalamus (ANT). Using recordings in the human thalamus of three surgical patients during natural vision, we found that saccades and visual stimulus onset both modulate neural activity, but with distinct field potential morphologies. Specifically, we found that fixation-locked field potentials had a component that preceded saccade onset. It was followed by an early negativity around 50 ms after fixation onset which is significantly faster than any response to visual stimulus presentation. The timing of these events suggests that the ANT is predictively modulated before the saccadic eye movement. We also found oscillatory phase concentration, peaking at 3–4 Hz, coincident with suppression of Broadband High-frequency Activity (BHA; 80–180 Hz), both locked to fixation onset supporting the idea that neural oscillations in these nuclei are reorganized to a low excitability state right after fixation onset. These findings show that during real-world natural visual exploration neural dynamics in the human ANT is influenced by visual and oculomotor events, which supports the idea that ANT, apart from their contribution to episodic memory, also play a role in natural vision.

scholarly journals Eye movements modulate neural activity in the human anterior thalamus during visual active sensing

2020 ◽  
Author(s):  
Marcin Leszczynski ◽  
Tobias Staudigl ◽  
Leila Chaieb ◽  
Simon Jonas Enkirch ◽  
Juergen Fell ◽  
...  
Keyword(s):  
Eye Movements ◽  
Medial Temporal Lobe ◽  
Neuronal Excitability ◽  
Saccadic Eye Movements ◽  
Visual Exploration ◽  
Active Sensing ◽  
Phase Reset ◽  
Anterior Thalamus ◽  
Human Thalamus ◽  
Visual Cortices

AbstractHumans and other primates explore visual scenes by active sensing, using saccadic eye movements to relocate the fovea and sample different bits of information multiple times per second. Saccades induce a phase reset of ongoing neuronal oscillations in primary and higher-order visual cortices and medial temporal lobe. As a result, neuron ensembles are shifted to a common state at the time visual input propagates through the system (i.e., just after fixation). The extent of the brain’s circuitry modulated by saccades is not yet known. Here, we evaluate the possibility that saccadic phase reset impacts the anterior nuclei of the thalamus (ANT). Using rare recordings in the human thalamus of three surgical patients, we found saccade-related phase concentration, peaking at 3-4 Hz, coincident with suppression of Broadband High-frequency Activity (BHA; 80-180 Hz). Our results provide evidence for saccade-related modulation of neuronal excitability dynamics in the ANT, consistent with the idea that these nuclei are engaged during visual active sensing. These findings show that during real-world active visual exploration neural dynamics in the human ANT, a part of extended hippocampal–diencephalic system for episodic memory, exhibit modulations that might be underestimated in typical passive viewing.

scholarly journals Scene-selective coding by single neurons in the human parahippocampal cortex

2017 ◽  
Vol 114 (5) ◽  
pp. 1153-1158 ◽  
Author(s):  
Florian Mormann ◽  
Simon Kornblith ◽  
Moran Cerf ◽  
Matias J. Ison ◽  
Alexander Kraskov ◽  
...  
Keyword(s):  
Medial Temporal Lobe ◽  
Field Potential ◽  
Stimulus Presentation ◽  
Related Field ◽  
Parahippocampal Cortex ◽  
Neurosurgical Patients ◽  
Electrophysiological Findings ◽  
Lesion Studies ◽  
Bulk Tissue ◽  
Insight Into

Imaging, electrophysiological, and lesion studies have shown a relationship between the parahippocampal cortex (PHC) and the processing of spatial scenes. Our present knowledge of PHC, however, is restricted to the macroscopic properties and dynamics of bulk tissue; the behavior and selectivity of single parahippocampal neurons remains largely unknown. In this study, we analyzed responses from 630 parahippocampal neurons in 24 neurosurgical patients during visual stimulus presentation. We found a spatially clustered subpopulation of scene-selective units with an associated event-related field potential. These units form a population code that is more distributed for scenes than for other stimulus categories, and less sparse than elsewhere in the medial temporal lobe. Our electrophysiological findings provide insight into how individual units give rise to the population response observed with functional imaging in the parahippocampal place area.

Task-demands and audio-visual stimulus configurations modulate neural activity in the human thalamus

NeuroImage ◽  
2013 ◽  
Vol 66 ◽  
pp. 110-118 ◽  
Author(s):  
Björn Bonath ◽  
Sascha Tyll ◽  
Eike Budinger ◽  
Kerstin Krauel ◽  
Jens-Max Hopf ◽  
...  
Keyword(s):  
Visual Stimulus ◽  
Neural Activity ◽  
Task Demands ◽  
Human Thalamus

scholarly journals Responses of Human Medial Temporal Lobe Neurons Are Modulated by Stimulus Repetition

2010 ◽  
Vol 103 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Carlos Pedreira ◽  
Florian Mormann ◽  
Alexander Kraskov ◽  
Moran Cerf ◽  
Itzhak Fried ◽  
...  
Keyword(s):  
Firing Rate ◽  
Temporal Lobe ◽  
Neural Activity ◽  
Medial Temporal Lobe ◽  
Declarative Memory ◽  
Stimulus Presentation ◽  
Single Neurons ◽  
Stimulus Repetition ◽  
Repeated Stimulus ◽  
Visual Inputs

Recent studies have reported the presence of single neurons with strong responses to visual inputs in the human medial temporal lobe. Here we show how repeated stimulus presentation—photos of celebrities and familiar individuals, landmark buildings, animals, and objects—modulates the firing rate of these cells: a consistent decrease in the neural activity was registered as images were repeatedly shown during experimental sessions. The effect of repeated stimulus presentation was not the same for all medial temporal lobe areas. These findings are consistent with the view that medial temporal lobe neurons link visual percepts to declarative memory.

Modulation of medial temporal lobe activity in epilepsy patients with hippocampal sclerosis during verbal working memory

2009 ◽  
Vol 15 (4) ◽  
pp. 536-546 ◽  
Author(s):  
PABLO CAMPO ◽  
FERNANDO MAESTÚ ◽  
IRENE GARCÍA-MORALES ◽  
ANTONIO GIL-NAGEL ◽  
BRYAN STRANGE ◽  
...  
Keyword(s):  
Working Memory ◽  
Episodic Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Time Course ◽  
Hippocampal Sclerosis ◽  
Stimulus Presentation ◽  
Verbal Working Memory ◽  
Compelling Evidence ◽  
Electrophysiological Studies

AbstractIt has been traditionally assumed that medial temporal lobe (MTL) is not required for working memory (WM). However, animal lesion and electrophysiological studies and human neuropsychological and neuroimaging studies have provided increasing evidences of a critical involvement of MTL in WM. Based on previous findings, the central aim of this study was to investigate the contribution of the MTL to verbal WM encoding. Here, we used magnetoencephalography (MEG) to compare the patterns of MTL activation of 9 epilepsy patients suffering from left hippocampal sclerosis with those of 10 healthy matched controls while they performed a verbal WM task. MEG recordings allow detailed tracking of the time course of MTL activation. We observed impaired WM performance associated with changes in the dynamics of MTL activity in epilepsy patients. Specifically, whereas patients showed decreased activity in damaged MTL, activity in the contralateral MTL was enhanced, an effect that became significant in the 600- to 700-ms interval after stimulus presentation. These findings strongly support the crucial contribution of MTL to verbal WM encoding and provide compelling evidence for the proposal that MTL contributes to both episodic memory and WM. Whether this pattern is signaling reorganization or a normal use of a damaged structure is discussed. (JINS, 2009, 15, 536–546.)

Investigating task and modality switching costs using bimodal stimuli

2012 ◽  
Vol 25 (0) ◽  
pp. 22
Author(s):  
Raj Sandhu ◽  
Ben Dyson
Keyword(s):  
Task Switching ◽  
Visual Stimulus ◽  
Switching Costs ◽  
Stimulus Presentation ◽  
Task Type ◽  
Task Repetition ◽  
Specific Combination ◽  
Task Change ◽  
Modality Switching ◽  
And Task

Investigations of concurrent task and modality switching effects have to date been studied under conditions of uni-modal stimulus presentation. As such, it is difficult to directly compare resultant task and modality switching effects, as the stimuli afford both tasks on each trial, but only one modality. The current study investigated task and modality switching using bi-modal stimulus presentation under various cue conditions: task and modality (double cue), either task or modality (single cue) or no cue. Participants responded to either the identity or the position of an audio–visual stimulus. Switching effects were defined as staying within a modality/task (repetition) or switching into a modality/task (change) from trial n − 1 to trial n, with analysis performed on trial n data. While task and modality switching costs were sub-additive across all conditions replicating previous data, modality switching effects were dependent on the modality being attended, and task switching effects were dependent on the task being performed. Specifically, visual responding and position responding revealed significant costs associated with modality and task switching, while auditory responding and identity responding revealed significant gains associated with modality and task switching. The effects interacted further, revealing that costs and gains associated with task and modality switching varying with the specific combination of modality and task type. The current study reconciles previous data by suggesting that efficiently processed modality/task information benefits from repetition while less efficiently processed information benefits from change due to less interference of preferred processing across consecutive trials.

scholarly journals Stimulus Feature-Specific Information Flow Along the Columnar Cortical Microcircuit Revealed by Multivariate Laminar Spiking Analysis

2020 ◽  
Vol 14 ◽  
Author(s):  
David A. Tovar ◽  
Jacob A. Westerberg ◽  
Michele A. Cox ◽  
Kacie Dougherty ◽  
Thomas A. Carlson ◽  
...  
Keyword(s):  
Neural Activity ◽  
Visual Stimulation ◽  
Brain Activity ◽  
Contextual Information ◽  
Univariate Analysis ◽  
Stimulus Presentation ◽  
Population Level ◽  
Granular Cell ◽  
Stimulus Orientation ◽  
Specific Information

Most of the mammalian neocortex is comprised of a highly similar anatomical structure, consisting of a granular cell layer between superficial and deep layers. Even so, different cortical areas process different information. Taken together, this suggests that cortex features a canonical functional microcircuit that supports region-specific information processing. For example, the primate primary visual cortex (V1) combines the two eyes' signals, extracts stimulus orientation, and integrates contextual information such as visual stimulation history. These processes co-occur during the same laminar stimulation sequence that is triggered by the onset of visual stimuli. Yet, we still know little regarding the laminar processing differences that are specific to each of these types of stimulus information. Univariate analysis techniques have provided great insight by examining one electrode at a time or by studying average responses across multiple electrodes. Here we focus on multivariate statistics to examine response patterns across electrodes instead. Specifically, we applied multivariate pattern analysis (MVPA) to linear multielectrode array recordings of laminar spiking responses to decode information regarding the eye-of-origin, stimulus orientation, and stimulus repetition. MVPA differs from conventional univariate approaches in that it examines patterns of neural activity across simultaneously recorded electrode sites. We were curious whether this added dimensionality could reveal neural processes on the population level that are challenging to detect when measuring brain activity without the context of neighboring recording sites. We found that eye-of-origin information was decodable for the entire duration of stimulus presentation, but diminished in the deepest layers of V1. Conversely, orientation information was transient and equally pronounced along all layers. More importantly, using time-resolved MVPA, we were able to evaluate laminar response properties beyond those yielded by univariate analyses. Specifically, we performed a time generalization analysis by training a classifier at one point of the neural response and testing its performance throughout the remaining period of stimulation. Using this technique, we demonstrate repeating (reverberating) patterns of neural activity that have not previously been observed using standard univariate approaches.

scholarly journals Estimation of Bladder Pressure and Volume from the Neural Activity of Lumbosacral Dorsal Horn Using a Long-Short-Term-Memory-based Deep Neural Network

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Milad Jabbari ◽  
Abbas Erfanian
Keyword(s):  
Neural Network ◽  
Neural Activity ◽  
Short Term Memory ◽  
Field Potential ◽  
Bladder Function ◽  
Bladder Pressure ◽  
Short Term ◽  
Term Memory ◽  
Deep Recurrent Neural Network ◽  
Long Short Term Memory

AbstractIn this paper, we propose a deep recurrent neural network (DRNN) for the estimation of bladder pressure and volume from neural activity recorded directly from spinal cord gray matter neurons. The model was based on the Long Short-Term Memory (LSTM) architecture, which has emerged as a general and effective model for capturing long-term temporal dependencies with good generalization performance. In this way, training the network with the data recorded from one rat could lead to estimating the bladder status of different rats. We combined modeling of spiking and local field potential (LFP) activity into a unified framework to estimate the pressure and volume of the bladder. Moreover, we investigated the effect of two-electrode recording on decoding performance. The results show that the two-electrode recordings significantly improve the decoding performance compared to single-electrode recordings. The proposed framework could estimate bladder pressure and volume with an average normalized root-mean-squared (NRMS) error of 14.9 ± 4.8% and 19.7 ± 4.7% and a correlation coefficient (CC) of 83.2 ± 3.2% and 74.2 ± 6.2%, respectively. This work represents a promising approach to the real-time estimation of bladder pressure/volume in the closed-loop control of bladder function using functional electrical stimulation.

scholarly journals The functional organization of human epileptic hippocampus

2016 ◽  
Vol 115 (6) ◽  
pp. 3140-3145 ◽  
Author(s):  
Petr Klimes ◽  
Juliano J. Duque ◽  
Ben Brinkmann ◽  
Jamie Van Gompel ◽  
Matt Stead ◽  
...  
Keyword(s):  
Spatial Scale ◽  
Local Field ◽  
Medial Temporal Lobe ◽  
Slow Wave Sleep ◽  
Functional Organization ◽  
Spectral Power ◽  
Spatial Scales ◽  
Field Potential ◽  
Brain Regions ◽  
Behavioral State

The function and connectivity of human brain is disrupted in epilepsy. We previously reported that the region of epileptic brain generating focal seizures, i.e., the seizure onset zone (SOZ), is functionally isolated from surrounding brain regions in focal neocortical epilepsy. The modulatory effect of behavioral state on the spatial and spectral scales over which the reduced functional connectivity occurs, however, is unclear. Here we use simultaneous sleep staging from scalp EEG with intracranial EEG recordings from medial temporal lobe to investigate how behavioral state modulates the spatial and spectral scales of local field potential synchrony in focal epileptic hippocampus. The local field spectral power and linear correlation between adjacent electrodes provide measures of neuronal population synchrony at different spatial scales, ∼1 and 10 mm, respectively. Our results show increased connectivity inside the SOZ and low connectivity between electrodes in SOZ and outside the SOZ. During slow-wave sleep, we observed decreased connectivity for ripple and fast ripple frequency bands within the SOZ at the 10 mm spatial scale, while the local synchrony remained high at the 1 mm spatial scale. Further study of these phenomena may prove useful for SOZ localization and help understand seizure generation, and the functional deficits seen in epileptic eloquent cortex.

scholarly journals Induced cortical oscillations in turtle cortex are coherent at the mesoscale of population activity, but not at the microscale of the membrane potential of neurons

2017 ◽  
Vol 118 (5) ◽  
pp. 2579-2591 ◽  
Author(s):  
Mahmood S. Hoseini ◽  
Jeff Pobst ◽  
Nathaniel Wright ◽  
Wesley Clawson ◽  
Woodrow Shew ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Membrane Potential ◽  
Neural Activity ◽  
Visual Stimulation ◽  
Field Potential ◽  
Brain Regions ◽  
Large Trial ◽  
Population Activity ◽  
Potential Oscillations ◽  
Time Frequency

Bursts of oscillatory neural activity have been hypothesized to be a core mechanism by which remote brain regions can communicate. Such a hypothesis raises the question to what extent oscillations are coherent across spatially distant neural populations. To address this question, we obtained local field potential (LFP) and membrane potential recordings from the visual cortex of turtle in response to visual stimulation of the retina. The time-frequency analysis of these recordings revealed pronounced bursts of oscillatory neural activity and a large trial-to-trial variability in the spectral and temporal properties of the observed oscillations. First, local bursts of oscillations varied from trial to trial in both burst duration and peak frequency. Second, oscillations of a given recording site were not autocoherent; i.e., the phase did not progress linearly in time. Third, LFP oscillations at spatially separate locations within the visual cortex were more phase coherent in the presence of visual stimulation than during ongoing activity. In contrast, the membrane potential oscillations from pairs of simultaneously recorded pyramidal neurons showed smaller phase coherence, which did not change when switching from black screen to visual stimulation. In conclusion, neuronal oscillations at distant locations in visual cortex are coherent at the mesoscale of population activity, but coherence is largely absent at the microscale of the membrane potential of neurons. NEW & NOTEWORTHY Coherent oscillatory neural activity has long been hypothesized as a potential mechanism for communication across locations in the brain. In this study we confirm the existence of coherent oscillations at the mesoscale of integrated cortical population activity. However, at the microscopic level of neurons, we find no evidence for coherence among oscillatory membrane potential fluctuations. These results raise questions about the applicability of the communication through coherence hypothesis to the level of the membrane potential.

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