scholarly journals Spatial mnemonic encoding: Theta power decreases co-occur with medial temporal lobe BOLD increases during the usage of the Method of Loci

2016 ◽  
Author(s):  
M.-C. Fellner ◽  
G. Volberg ◽  
M. Wimber ◽  
M. Goldhacker ◽  
M. W. Greenlee ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Negative Relationship ◽  
Low Frequency ◽  
Theta Oscillations ◽  
Oscillatory Activity ◽  
Bold Signal ◽  
Memory Processes ◽  
Theta Power ◽  
Method Of Loci

AbstractThe Method of Loci is one, if not the most, efficient mnemonic encoding strategy. This strategy combines the core cognitive processes commonly linked to medial temporal lobe (MTL) activity: spatial processing and associative memory processes. During such tasks fMRI studies consistently demonstrate increases in medial temporal lobe (MTL) activity, while electrophysiological studies have emphasized the important role of theta oscillations (3-8 Hz) in the MTL. How MTL activity is linked to theta oscillatory EEG power, however, is unknown. Specifically, it is not known whether increases or decreases in MTL theta power are associated with increased BOLD signal. To investigate this question we recorded EEG and fMRI while participants used the spatial Method of Loci contrasted to the Pegword Method, a similarly associative but non spatial mnemonic. Surprisingly, the more effective spatial mnemonic induced a pronounced theta power decrease in the left MTL compared to the non-spatial associative mnemonic strategy. This effect was mirrored by BOLD signal increases in the MTL. This pattern of results suggests that theta oscillations in the MTL are negatively related to BOLD signal increases. These findings extend the well-known negative relation of alpha/beta oscillations and BOLD signals in the cortex to theta oscillations in the MTL. The results also demonstrate that decreases in theta power can index MTL involvement during encoding.Significance StatementStudies investigating the oscillatory correlates of memory encoding largely focus on activity in the theta frequency and often implicitly assume that increases in theta activity reflect similar processes as typically reported increases MTL activity changes in fMRI studies. The presented study found decreases in theta power, not increases, closely mapping to MTL BOLD signal increases during the same paradigm. This finding is in line with studies showing a negative relationship between low frequency power and BOLD changes in the cortex, but challenges the assumption that theta power increases reflect MTL activity. The reported findings importantly contribute to answer the question of how and which oscillatory activity indexes MTL memory processes.

scholarly journals Spatial Mnemonic Encoding: Theta Power Decreases and Medial Temporal Lobe BOLD Increases Co-Occur during the Usage of the Method of Loci

eNeuro ◽  
2016 ◽  
Vol 3 (6) ◽  
pp. ENEURO.0184-16.2016 ◽  
Author(s):  
Marie-Christin Fellner ◽  
Gregor Volberg ◽  
Maria Wimber ◽  
Markus Goldhacker ◽  
Mark W. Greenlee ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Theta Power ◽  
Method Of Loci

Low frequency traveling waves in the human cortex coordinate neural activity across spatial scales

2020 ◽  
Author(s):  
Vishnu Sreekumar ◽  
John H. Wittig ◽  
Julio Chapeton ◽  
Sara K. Inati ◽  
Kareem A. Zaghloul
Keyword(s):  
Temporal Lobe ◽  
Traveling Waves ◽  
Verbal Memory ◽  
Single Unit ◽  
Spatial Scales ◽  
Memory Task ◽  
Low Frequency ◽  
Oscillatory Activity ◽  
Neural Communication ◽  
Macro Scale

AbstractTraveling waves of oscillatory activity are thought to influence neuronal spiking, providing a spatiotemporal frame-work for neural communication. However, no direct link has been established between traveling waves and single unit spiking in humans. We examined traveling waves in the human lateral temporal lobe by using recordings from intracranial electrodes implanted in twenty participants for seizure monitoring as they performed a paired-associates verbal memory task. We observed ubiquitous low frequency traveling waves across the temporal lobe. While wave occurrence in a broad low frequency range did not differ between successful and unsuccessful memory conditions, in a subset of participants with microelectrode recordings, we found that macro-scale waves co-occurred with micro-scale waves, which in turn were temporally locked to single unit spiking. This temporal coordination between traveling waves at different spatial scales and between waves and neuronal spiking in the human brain suggests a role for traveling waves in neural communication.

scholarly journals Medial temporal lobe functional connectivity predicts stimulation-induced theta power

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
E. A. Solomon ◽  
J. E. Kragel ◽  
R. Gross ◽  
B. Lega ◽  
M. R. Sperling ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Theta Power

scholarly journals Theta Oscillations Mediate Interaction between Prefrontal Cortex and Medial Temporal Lobe in Human Memory

2009 ◽  
Vol 20 (7) ◽  
pp. 1604-1612 ◽  
Author(s):  
Kristopher L. Anderson ◽  
Rajasimhan Rajagovindan ◽  
Georges A. Ghacibeh ◽  
Kimford J. Meador ◽  
Mingzhou Ding
Keyword(s):  
Prefrontal Cortex ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Human Memory ◽  
Theta Oscillations

Behavioral correlates of human hippocampal delta and theta oscillations during navigation

2011 ◽  
Vol 105 (4) ◽  
pp. 1747-1755 ◽  
Author(s):  
Andrew J. Watrous ◽  
Itzhak Fried ◽  
Arne D. Ekstrom
Keyword(s):  
Low Frequency ◽  
Theta Activity ◽  
Theta Oscillations ◽  
Spatial Updating ◽  
Behavioral Correlates ◽  
Theta Power ◽  
Relevant Variables ◽  
Spatial View ◽  
Intracranial Electrodes

Previous rodent studies demonstrate movement-related increases in theta oscillations, and recent evidence suggests that multiple navigationally relevant variables are reflected in this activity. Human invasive recordings have revealed movement-related modulations in delta and theta activity, although it is unclear whether additional behavioral variables are responsible for modulating this neural activity during navigation. We tested the role of delta and theta oscillations during navigation by addressing whether spatial-related processing, in addition to speed and task variables, modulates delta and theta activity. Recording from 317 hippocampal intracranial electrodes in 10 patients undergoing seizure monitoring, we observed increasing delta and theta power with increasing virtual speed at significantly more electrodes than would be expected by chance, replicating previous findings in nonhuman mammals. Delta and theta power were more consistently modulated, however, as a function of spatial view, including when subjects looked at stores in the virtual environment both to find a relevant goal or for spatial updating. A significantly larger proportion of electrodes showed view-related effects than speed-related modulations. Although speed, task, and spatial view affected delta and theta activity, individual electrodes were most frequently modulated by only one variable, rather than a combination of variables. These electrodes likely sampled independent delta and theta generators, which reflected movement-related and allocentric processing, respectively. These results extend previous findings in nonhuman mammals and humans, expanding our knowledge of the role of human hippocampal low-frequency oscillations in navigation.

scholarly journals Revisiting the Role of the Medial Temporal Lobe in Motor Learning

2021 ◽  
pp. 1-18
Author(s):  
Samuel D. McDougle ◽  
Sarah A. Wilterson ◽  
Nicholas B. Turk-Browne ◽  
Jordan A. Taylor
Keyword(s):  
Motor Learning ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Declarative Memory ◽  
Action Selection ◽  
Memory Systems ◽  
Memory Processes ◽  
Multiple Memory Systems ◽  
Selection Strategies ◽  
Arbitrary Action

Abstract Classic taxonomies of memory distinguish explicit and implicit memory systems, placing motor skills squarely in the latter branch. This assertion is in part a consequence of foundational discoveries showing significant motor learning in amnesics. Those findings suggest that declarative memory processes in the medial temporal lobe (MTL) do not contribute to motor learning. Here, we revisit this issue, testing an individual (L. S. J.) with severe MTL damage on four motor learning tasks and comparing her performance to age-matched controls. Consistent with previous findings in amnesics, we observed that L. S. J. could improve motor performance despite having significantly impaired declarative memory. However, she tended to perform poorly relative to age-matched controls, with deficits apparently related to flexible action selection. Further supporting an action selection deficit, L. S. J. fully failed to learn a task that required the acquisition of arbitrary action–outcome associations. We thus propose a modest revision to the classic taxonomic model: Although MTL-dependent memory processes are not necessary for some motor learning to occur, they play a significant role in the acquisition, implementation, and retrieval of action selection strategies. These findings have implications for our understanding of the neural correlates of motor learning, the psychological mechanisms of skill, and the theory of multiple memory systems.

scholarly journals Theta Oscillations in the Human Medial Temporal Lobe during Real World Ambulatory Movement

2016 ◽  
Author(s):  
Zahra M. Aghajan ◽  
Peter Schuette ◽  
Tony Fields ◽  
Michelle Tran ◽  
Sameed Siddiqui ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Real World ◽  
Medial Temporal Lobe ◽  
Theta Rhythm ◽  
Human Subjects ◽  
Critical Role ◽  
Spike Timing ◽  
Theta Oscillations ◽  
Behavioral Correlates ◽  
Deep Brain

AbstractTheta oscillations play a critical role in learning and memory by coordinating the spiking activity of neuronal ensembles via mechanisms such as spike timing dependent plasticity1–7. This rhythm is present in rodents where it is continuously evident during movement at frequencies within 6-12Hz8,9. In humans, however, the presence of continuous theta rhythm has been elusive; indeed, a functionally similar theta is thought to occur at lower frequency ranges (3-7Hz) and in shorter bouts10–12. This lower frequency theta rhythm is observed during a variety of behaviors, including virtual navigation, but has never been tested during real world ambulatory movement. Here we examined the oscillatory properties of theta within the human medial temporal lobe (MTL) in freely moving human subjects chronically implanted with the clinical NeuroPace RNS® responsive neurostimulator device, capable of wireless recordings of continuous intracranial deep brain electroencephalographic (iEEG) activity. MTL iEEG recordings, together with sub-millimeter position tracking, revealed the presence of high frequency theta oscillations (6-12Hz) during ambulation. The prevalence of these oscillations was increased during fast movement compared to slow movement. These theta bouts, although occurring more frequently, were not significantly different in durations during fast versus slow movements. In a rare opportunity to study one subject with congenital blindness, we found that both the prevalence and duration of theta bouts were much greater than those in sighted subjects. Our results suggest that higher frequency theta indeed exists in humans during movement providing critical support for conserved neurobiological mechanisms for spatial navigation. The precise link between this pattern and its behavioral correlates will be an exciting area for future studies given this novel methodology for simultaneous motion capture and long term chronic recordings from deep brain targets during ambulatory human behavior.

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