scholarly journals Auditory Beat Stimulation Modulates Memory-Related Single-Neuron Activity in the Human Medial Temporal Lobe

2021 ◽  
Vol 11 (3) ◽  
pp. 364 ◽  
Author(s):  
Marlene Derner ◽  
Leila Chaieb ◽  
Gert Dehnen ◽  
Thomas P. Reber ◽  
Valeri Borger ◽  
...  
Keyword(s):  
Firing Rate ◽  
Medial Temporal Lobe ◽  
Memory Performance ◽  
Recognition Task ◽  
Homeostatic Plasticity ◽  
Neuron Activity ◽  
Shifting Baseline ◽  
Parahippocampal Cortex ◽  
Neurosurgical Patients ◽  
Single Neuron Activity

Auditory beats are amplitude-modulated signals (monaural beats) or signals that subjectively cause the perception of an amplitude modulation (binaural beats). We investigated the effects of monaural and binaural 5 Hz beat stimulation on neural activity and memory performance in neurosurgical patients performing an associative recognition task. Previously, we had reported that these beat stimulation conditions modulated memory performance in opposite directions. Here, we analyzed data from a patient subgroup, in which microwires were implanted in the amygdala, hippocampus, entorhinal cortex and parahippocampal cortex. We identified neurons responding with firing rate changes to binaural versus monaural 5 Hz beat stimulation. In these neurons, we correlated the differences in firing rates for binaural versus monaural beats to the memory-related differences for remembered versus forgotten items and associations. In the left hemisphere, we detected statistically significant negative correlations between firing rate differences for binaural versus monaural beats and remembered versus forgotten items/associations. Importantly, such negative correlations were also observed between beat stimulation-related firing rate differences in the pre-stimulus window and memory-related firing rate differences in the post-stimulus windows. In line with concepts of homeostatic plasticity, our findings suggest that beat stimulation is linked to memory performance via shifting baseline firing levels.

scholarly journals Auditory beat stimulation modulates memory-related single-neuron activity in the human medial temporal lobe

2020 ◽  
Author(s):  
M Derner ◽  
L Chaieb ◽  
G Dehnen ◽  
TP Reber ◽  
V Borger ◽  
...  
Keyword(s):  
Firing Rate ◽  
Medial Temporal Lobe ◽  
Memory Performance ◽  
Recognition Task ◽  
Homeostatic Plasticity ◽  
Neuron Activity ◽  
Shifting Baseline ◽  
Parahippocampal Cortex ◽  
First Case ◽  
Neurosurgical Patients

AbstractAuditory beats are composed of two sine waves using nearby frequencies, which can either be applied as a superposed signal to both ears or to each ear separately. In the first case, the beat sensation results from hearing an amplitude-modulated signal (monaural beat). In the second case, it is generated by phase-sensitive neurons in the brain stem (binaural beat). We investigated the effects of monaural and binaural 5 Hz beat stimulation on neural activity and memory performance in neurosurgical patients performing an associative recognition task. Previously, we had reported that these beat stimulation conditions modulated memory performance in opposite directions. Here, we analyzed data from a patient subgroup, in which microwires were implanted in the amygdala, hippocampus, entorhinal cortex and parahippocampal cortex. We identified neurons responding with firing rate changes to binaural versus monaural 5 Hz beat stimulation. In these neurons, we correlated the differences in firing rates for binaural versus monaural beats to the memory-related differences for remembered versus forgotten items and associations. In the left hemisphere for these neurons, we detected statistically significant negative correlations between firing rate differences for binaural versus monaural beats and remembered versus forgotten items/associations. Importantly, such negative correlations were also observed between beat stimulation-related firing rate differences in the baseline window and memory-related firing rate differences in the poststimulus windows. In line with concepts of homeostatic plasticity, we interpret our findings as indicating that beat stimulation is linked to memory performance via shifting baseline firing levels.

scholarly journals Egocentric Navigation Abilities Predict Episodic Memory Performance

2020 ◽  
Vol 14 ◽  
Author(s):  
Giorgia Committeri ◽  
Agustina Fragueiro ◽  
Maria Maddalena Campanile ◽  
Marco Lagatta ◽  
Ford Burles ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Semantic Memory ◽  
Path Integration ◽  
Medial Temporal Lobe ◽  
Declarative Memory ◽  
Memory Performance ◽  
Memory Task ◽  
Recognition Task ◽  
Future Research ◽  
Egocentric Navigation

The medial temporal lobe supports both navigation and declarative memory. On this basis, a theory of phylogenetic continuity has been proposed according to which episodic and semantic memories have evolved from egocentric (e.g., path integration) and allocentric (e.g., map-based) navigation in the physical world, respectively. Here, we explored the behavioral significance of this neurophysiological model by investigating the relationship between the performance of healthy individuals on a path integration and an episodic memory task. We investigated the path integration performance through a proprioceptive Triangle Completion Task and assessed episodic memory through a picture recognition task. We evaluated the specificity of the association between performance in these two tasks by including in the study design a verbal semantic memory task. We also controlled for the effect of attention and working memory and tested the robustness of the results by including alternative versions of the path integration and semantic memory tasks. We found a significant positive correlation between the performance on the path integration the episodic, but not semantic, memory tasks. This pattern of correlation was not explained by general cognitive abilities and persisted also when considering a visual path integration task and a non-verbal semantic memory task. Importantly, a cross-validation analysis showed that participants' egocentric navigation abilities reliably predicted episodic memory performance. Altogether, our findings support the hypothesis of a phylogenetic continuity between egocentric navigation and episodic memory and pave the way for future research on the potential causal role of egocentric navigation on multiple forms of episodic memory.

scholarly journals Patterns of single-neuron activity during associative recognition memory in the human medial temporal lobe

NeuroImage ◽  
2020 ◽  
Vol 221 ◽  
pp. 117214
Author(s):  
M. Derner ◽  
G. Dehnen ◽  
L. Chaieb ◽  
T.P. Reber ◽  
V. Borger ◽  
...  
Keyword(s):  
Recognition Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Single Neuron ◽  
Associative Recognition ◽  
Neuron Activity ◽  
Single Neuron Activity

Concomitant Single Neuron Activity, Local Field Potentials, and Cerebral Microdialysis in Neurosurgical Patients

Neurosurgery ◽  
1998 ◽  
Vol 43 (3) ◽  
pp. 706-706 ◽  
Author(s):  
Itzhak Fried ◽  
Eric Behnke ◽  
Nigel Maidment ◽  
Anatole Bragin ◽  
Katherine MacDonald ◽  
...  
Keyword(s):  
Local Field ◽  
Single Neuron ◽  
Local Field Potentials ◽  
Cerebral Microdialysis ◽  
Neuron Activity ◽  
Field Potentials ◽  
Neurosurgical Patients ◽  
Single Neuron Activity

scholarly journals Local Field Potentials and Spikes in the Human Medial Temporal Lobe are Selective to Image Category

2007 ◽  
Vol 19 (3) ◽  
pp. 479-492 ◽  
Author(s):  
Alexander Kraskov ◽  
Rodrigo Quian Quiroga ◽  
Leila Reddy ◽  
Itzhak Fried ◽  
Christof Koch
Keyword(s):  
Temporal Lobe ◽  
Local Field ◽  
Medial Temporal Lobe ◽  
Local Field Potentials ◽  
Neuron Activity ◽  
Separate Analysis ◽  
Field Potentials ◽  
Semantic Categories ◽  
Depth Electrodes ◽  
Neurosurgical Patients

Local field potentials (LFPs) reflect the averaged dendrosomatic activity of synaptic signals of large neuronal populations. In this study, we investigate the selectivity of LFPs and single neuron activity to semantic categories of visual stimuli in the medial temporal lobe of nine neurosurgical patients implanted with intracranial depth electrodes for clinical reasons. Strong selectivity to the category of presented images was found for the amplitude of LFPs in 8% of implanted microelectrodes and for the firing rates of single and multiunits in 14% of microelectrodes. There was little overlap between the LFP- and spike-selective microelectrodes. Separate analysis of the power and phase of LFPs revealed that the mean phase was category-selective around the θ frequency range and that the power of the LFPs was category-selective for high frequencies around the γ rhythm. Of the 36 microelectrodes with amplitude-selective LFPs, 30 were found in the hippocampus. Finally, it was possible to readout information about the category of stimuli presented to the patients with both spikes and LFPs. Combining spiking and LFP activity enhanced the decoding accuracy in comparison with the accuracy obtained with each signal alone, especially for short time intervals.

scholarly journals Spiking activity in the human hippocampus prior to encoding predicts subsequent memory

2020 ◽  
Vol 117 (24) ◽  
pp. 13767-13770 ◽  
Author(s):  
Zhisen J. Urgolites ◽  
John T. Wixted ◽  
Stephen D. Goldinger ◽  
Megan H. Papesh ◽  
David M. Treiman ◽  
...  
Keyword(s):  
Medial Temporal Lobe ◽  
Memory Performance ◽  
Recognition Task ◽  
Brain Regions ◽  
Anterior Cingulate ◽  
Continuous Series ◽  
Hippocampal Activity ◽  
Spiking Activity ◽  
Predictive Effect ◽  
Novel Words

Encoding activity in the medial temporal lobe, presumably evoked by the presentation of stimuli (postonset activity), is known to predict subsequent memory. However, several independent lines of research suggest that preonset activity also affects subsequent memory. We investigated the role of preonset and postonset single-unit and multiunit activity recorded from epilepsy patients as they completed a continuous recognition task. In this task, words were presented in a continuous series and eventually began to repeat. For each word, the patient’s task was to decide whether it was novel or repeated. We found that preonset spiking activity in the hippocampus (when the word was novel) predicted subsequent memory (when the word was later repeated). Postonset activity during encoding also predicted subsequent memory, but was simply a continuation of preonset activity. The predictive effect of preonset spiking activity was much stronger in the hippocampus than in three other brain regions (amygdala, anterior cingulate, and prefrontal cortex). In addition, preonset and postonset activity around the encoding of novel words did not predict memory performance for novel words (i.e., correctly classifying the word as novel), and preonset and postonset activity around the time of retrieval did not predict memory performance for repeated words (i.e., correctly classifying the word as repeated). Thus, the only predictive effect was between preonset activity (along with its postonset continuation) at the time of encoding and subsequent memory. Taken together, these findings indicate that preonset hippocampal activity does not reflect general arousal/attention but instead reflects what we term “attention to encoding.”

scholarly journals Neural Activity in the Hippocampus and Perirhinal Cortex during Encoding Is Associated with the Durability of Episodic Memory

2010 ◽  
Vol 22 (11) ◽  
pp. 2652-2662 ◽  
Author(s):  
Valerie A. Carr ◽  
Indre V. Viskontas ◽  
Stephen A. Engel ◽  
Barbara J. Knowlton
Keyword(s):  
Neural Activity ◽  
Medial Temporal Lobe ◽  
Memory Performance ◽  
Perirhinal Cortex ◽  
Memory Formation ◽  
Short Delay ◽  
Parahippocampal Cortex ◽  
The Relationship ◽  
Over Time ◽  
Subsequent Memory Effect

Studies examining medial temporal lobe (MTL) involvement in memory formation typically assess memory performance after a single, short delay. Thus, the relationship between MTL encoding activity and memory durability over time remains poorly characterized. To explore this relationship, we scanned participants using high-resolution functional imaging of the MTL as they encoded object pairs; using the remember/know paradigm, we then assessed memory performance for studied items both 10 min and 1 week later. Encoding trials were classified as either subsequently recollected across both delays, transiently recollected (i.e., recollected at 10 min but not after 1 week), consistently familiar, or consistently forgotten. Activity in perirhinal cortex (PRC) and a hippocampal subfield comprising the dentate gyrus and CA fields 2 and 3 reflected successful encoding only when items were recollected consistently across both delays. Furthermore, in PRC, encoding activity for items that later were consistently recollected was significantly greater than that for transiently recollected and consistently familiar items. Parahippocampal cortex, in contrast, showed a subsequent memory effect during encoding of items that were recollected after 10 min, regardless of whether they also were recollected after 1 week. These data suggest that MTL subfields contribute uniquely to the formation of memories that endure over time, and highlight a role for PRC in supporting subsequent durable episodic recollection.

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.

scholarly journals Persistent Single-Neuron Activity during Working Memory in the Human Medial Temporal Lobe

2017 ◽  
Vol 27 (7) ◽  
pp. 1026-1032 ◽  
Author(s):  
Simon Kornblith ◽  
Rodrigo Quian Quiroga ◽  
Christof Koch ◽  
Itzhak Fried ◽  
Florian Mormann
Keyword(s):  
Working Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Single Neuron ◽  
Neuron Activity ◽  
Single Neuron Activity

scholarly journals Single-neuron representations of spatial targets in humans

2019 ◽  
Author(s):  
Melina Tsitsiklis ◽  
Jonathan Miller ◽  
Salman E. Qasim ◽  
Cory S. Inman ◽  
Robert E. Gross ◽  
...  
Keyword(s):  
Medial Temporal Lobe ◽  
Single Neuron ◽  
Spatial Information ◽  
Memory Task ◽  
Spatial Location ◽  
Task Demands ◽  
Neuron Activity ◽  
Neural Basis ◽  
Firing Rates ◽  
Neurosurgical Patients

SummaryThe hippocampus and surrounding medial-temporal-lobe (MTL) structures are critical for both memory and spatial navigation, but we do not fully understand the neuronal representations used to support these behaviors. Much research has examined how the MTL neurally represents spatial information, such as with “place cells” that represent the current location or “head-direction cells” that code for the current heading. In addition to behaviors that require an animal to attend to the current spatial location, navigating to remote destinations is a common part of daily life. To examine the neural basis of these behaviors we recorded single-neuron activity from neurosurgical patients playing Treasure Hunt, a virtual-reality spatial-memory task. By analyzing how the activity of these neurons related to behavior in Treasure Hunt, we found that the firing rates of many MTL neurons during navigation significantly changed depending on the position of the current spatial target. In addition, we observed neurons whose firing rates during navigation were tuned to specific heading directions in the environment, and others whose activity changed depending on the timing within the trial. By showing that neurons in our task represent remote locations rather than the subject’s own position, our results suggest that the human MTL can represent remote spatial information according to task demands.

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