scholarly journals When encodong yields remembering: insights from event-related neuroimaging

1999 ◽  
Vol 354 (1387) ◽  
pp. 1307-1324 ◽  
Author(s):  
Anthony D. Wagner ◽  
Wilma Koutstaal ◽  
Daniel L. Schacter

To understand human memory, it is important to determine why some experiences are remembered whereas others are forgotten. Until recently, insights into the neural bases of human memory encoding, the processes by which information is transformed into an enduring memory trace, have primarily been derived from neuropsychological studies of humans with select brain lesions. The advent of functional neuroimaging methods, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), has provided a new opportunity to gain additional understanding of how the brain supports memory formation. Importantly, the recent development of event–related fMRI methods now allows for examination of trial–by–trial differences in neural activity during encoding and of the consequences of these differences for later remembering. In this review, we consider the contributions of PET and fMRI studies to the understanding of memory encoding, placing a particular emphasis on recent event–related fMRI studies of the Dm effect: that is, differences in neural activity during encoding that are related to differences in subsequent memory. We then turn our attention to the rich literature on the Dm effect that has emerged from studies using event–related potentials (ERPs). It is hoped that the integration of findings from ERP studies, which offer higher temporal resolution, with those from event–related fMRI studies, which offer higher spatial resolution, will shed new light on when and why encoding yields subsequent remembering.

1997 ◽  
Vol 8 (3) ◽  
pp. 250-257 ◽  
Author(s):  
Marcia K. Johnson ◽  
Scott F. Nolde ◽  
Mara Mather ◽  
John Kounios ◽  
Daniel L. Schacter ◽  
...  

Event-related potentials (ERPs) were compared for correct recognitions of previously presented words and false recognitions of associatively related, nonpresented words (lures) When the test items were presented blocked by test type (old, new, lure), waveforms for old and lure items were different, especially at frontal and left parietal electrode sites, consistent with previous positron emission tomography (PET) data (Schacter, Reiman, et al, 1996) When the test format randomly intermixed the types of items, waveforms for old and lure items were more similar We suggest that test format affects the type of processing subjects engage in, consistent with expectations from the source-monitoring framework (Johnson, Hashtroudi, & Lindsay, 1993) These results also indicate that brain activity as assessed by neuroimaging designs requiring blocked presentation of trials (e.g., PET) do not necessarily reflect the brain activity that occurs in cognitive-behavioral paradigms, in which types of test trials are typically intermixed


2007 ◽  
Vol 19 (11) ◽  
pp. 1776-1789 ◽  
Author(s):  
Leun J. Otten ◽  
Josefin Sveen ◽  
Angela H. Quayle

Research into the neural underpinnings of memory formation has focused on the encoding of familiar verbal information. Here, we address how the brain supports the encoding of novel information that does not have meaning. Electrical brain activity was recorded from the scalps of healthy young adults while they performed an incidental encoding task (syllable judgments) on separate series of words and “nonwords” (nonsense letter strings that are orthographically legal and pronounceable). Memory for the items was then probed with a recognition memory test. For words as well as nonwords, event-related potentials differed depending on whether an item would subsequently be remembered or forgotten. However, the polarity and timing of the effect varied across item type. For words, subsequently remembered items showed the usually observed positive-going, frontally distributed modulation from around 600 msec after word onset. For nonwords, by contrast, a negative-going, spatially widespread modulation predicted encoding success from 1000 msec onward. Nonwords also showed a modulation shortly after item onset. These findings imply that the brain supports the encoding of familiar and unfamiliar letter strings in qualitatively different ways, including the engagement of distinct neural activity at different points in time. The processing of semantic attributes plays an important role in the encoding of words and the associated positive frontal modulation.


2000 ◽  
Vol 12 (3) ◽  
pp. 127-141 ◽  
Author(s):  
Ken A. Paller

Neuropsychological studies of memory disorders have played a prominent role in the development of theories of memory. To test and refine such theories in future, it will be advantageous to include research that utilizes physiological measures of the neural events responsible for memory. Measures of the electrical activity of the brain in the form of event-related potentials (ERPs) provide one source of such information. Recent results suggest that these real-time measures reflect relevant encoding and retrieval operations. In particular, distinct electrical responses have been associated with recollective processing of words and with priming of visual word-form. This source of evidence can thus enrich our understanding of both the cognitive structure and neural substrates of human memory.


2007 ◽  
Vol 10 (2) ◽  
pp. 117-119 ◽  
Author(s):  
PING LI ◽  
DAVID W. GREEN

In the last decade there has been a surge of interest in the use of neuroimaging tools such as event-related potentials (ERP) and functional magnetic resonance imaging (fMRI) to examine critical issues in the representation and processing of multiple languages in the brain. In 2001, David Green edited a special issue for Bilingualism: Language and Cognition on the cognitive neuroscience of bilingualism that involved studies of bilingual populations in English, German, Italian, and Japanese. According to a review by Vaid and Hull (2002), by 2001, there were at least 25 fMRI studies and 13 PET (positron emission tomography) studies of bilingual language processing in healthy individuals. This number has grown more rapidly since 2001. Many of these neuroscience studies of bilingualism have also appeared in top science journals and attracted widespread attention.


2019 ◽  
Vol 31 (4) ◽  
pp. 488-501 ◽  
Author(s):  
Takakuni Suzuki ◽  
Kaylin E. Hill ◽  
Belel Ait Oumeziane ◽  
Dan Foti ◽  
Douglas B. Samuel

1983 ◽  
Vol 17 (4) ◽  
pp. 307-318 ◽  
Author(s):  
H. G. Stampfer

This article suggests that the potential usefulness of event-related potentials in psychiatry has not been fully explored because of the limitations of various approaches to research adopted to date, and because the field is still undergoing rapid development. Newer approaches to data acquisition and methods of analysis, combined with closer co-operation between medical and physical scientists, will help to establish the practical application of these signals in psychiatric disorders and assist our understanding of psychophysiological information processing in the brain. Finally, it is suggested that psychiatrists should seek to understand these techniques and the data they generate, since they provide more direct access to measures of complex cerebral processes than current clinical methods.


Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3918 ◽  
Author(s):  
Goded Shahaf ◽  
Pora Kuperman ◽  
Yuval Bloch ◽  
Shahak Yariv ◽  
Yelena Granovsky

Migraine attacks can cause significant discomfort and reduced functioning for days at a time, including the pre-ictal and post-ictal periods. During the inter-ictsal period, however, migraineurs seem to function normally. It is puzzling, therefore, that event-related potentials of migraine patients often differ in the asymptomatic and inter-ictal period. Part of the electrophysiological dynamics demonstrated in the migraine cycle are attention related. In this pilot study we evaluated an easy-to-use new marker, the Brain Engagement Index (BEI), for attention monitoring during the migraine cycle. We sampled 12 migraine patients for 20 days within one calendar month. Each session consisted of subjects’ reports of stress level and migraine-related symptoms, and a 5 min EEG recording, with a 2-electrode EEG device, during an auditory oddball task. The first minute of the EEG sample was analyzed. Repetitive samples were also obtained from 10 healthy controls. The brain engagement index increased significantly during the pre-ictal (p ≈ 0.001) and the ictal (p ≈ 0.020) periods compared with the inter-ictal period. No difference was observed between the pre-ictal and ictal periods. Control subjects demonstrated intermediate Brain Engagement Index values, that is, higher than inter-ictal, yet lower than pre-ictal. Our preliminary results demonstrate the potential advantage of the use of a simple EEG system for improved prediction of migraine attacks. Further study is required to evaluate the efficacy of the Brain Engagement Index in monitoring the migraine cycle and the possible effects of interventions.


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