Spatio-temporal patterns of brain magnetic activity during a memory task in Alzheimer's disease

Maestú, Fernando; Fernández, Alberto; Simos, Panagiotis G.; Gil-Gregorio, Pedro; Amo, Carlos; Rodríguez, R; Arrazola, Juan; Alonso, Tomás Ortiz

doi:10.1097/00001756-200112210-00013

Cited by 58 publications

(44 citation statements)

References 18 publications

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“…Activity sources in temporoparietal (including the posterior portion of the superior and middle temporal gyri and the supramarginal gyrus) and occipital areas (including visual areas 17 and 18) were also taken into account. This measure is the most reliable and valid index of the degree of regional cerebral activation, specific to various language operations in several studies involving neurologically intact volunteers and patients (Breier et al 1999b;Papanicolaou et al 1999;Maestú et al 2001). Late activity sources were also found in temporoparietal areas (posterior portion of the superior and middle temporal gyri and the supramarginal gyrus) and in the occipital extrastriate areas.…”

Section: Methodsmentioning

confidence: 90%

The Hippocampus and Memory of Verbal and Pictorial Material

Papanicolaou¹,

Simos

Castillo

et al. 2002

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Recognition of words and kaleidoscope pictures showed a double dissociation of left and right hippocampal activity using magnetic source imaging (MSI). MSI has advantages over alternative imaging techniques that measure hemodynamic changes for identifying regional changes in brain activity in real time and on an individual subject basis without the need for image subtraction. In this study, lists of words or kaleidoscope pictures were presented for memorization followed by tests of list items and foils during which brain activity was recorded. There was greater activation in the left than the right hippocampus with abstract nouns (e.g., relief) and greater activation in the right than the left hippocampus with kaleidoscope pictures. This dissociation was evident on a case by case basis. This study demonstrates the specialization of the two medial temporal lobe (MTL) regions, including the hippocampi, for mnemonic processing of verbal and pictorial items that are difficult to encode verbally.

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Section: Methodsmentioning

confidence: 90%

The Hippocampus and Memory of Verbal and Pictorial Material

Papanicolaou¹,

Simos

Castillo

et al. 2002

Learn. Mem.

Self Cite

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“…Only one study has examined memory processing in patients with TLE using MEG (101), despite numerous MEG studies of encoding or retrieval of words (98,(102)(103)(104)(105)(106)(107)(108), faces (109,110), patterns (111), and letters (112)(113)(114) in other patient populations (111-115) and healthy controls. Hanlon et al (101) used an associative object-memory test in two TLE patients with hippocampal sclerosis and reported a shift of MEG activations to the contralateral, undamaged hippocampus.…”

Section: Megmentioning

confidence: 99%

The use of neuroimaging to study behavior in patients with epilepsy

McDonald¹

2008

Epilepsy & Behavior

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Structural and functional neuroimaging continue to play an increasing role in the presurgical evaluation of patients with epilepsy. In addition to their value for localizing the epileptogenic zone and eloquent cortex, neuroimaging is contributing to our understanding of mood comorbidity in epilepsy. Although the vast majority of research has focused on patients with temporal lobe epilepsy (TLE), neuroimaging studies of patients with frontal lobe epilepsy (FLE) and primary generalized epilepsy are increasing in number. In this review, structural and functional imaging modalities that have received considerable research attention in recent years are reviewed, along with an assessment of their strengths and limitations for understanding behavior in epilepsy. In addition, advances in multimodal imaging are discussed along with their potential application to the presurgical evaluation of patients with seizure disorders.

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“…Stimuli and task MEG scans were obtained in the context of a modified version of the Sternberg's letter-probe task (deToledo-Morrell et al 1991;Maestu et al 2001) in which a set of five letters was presented and participants were asked to keep the letters in mind. After the presentation of the five-letter set, a series of single letters (500 ms in duration with a random ISI between 2 and 3 s) was introduced one at a time, and participants were asked to press a button with their right hand when a member of the previous set was detected.…”

Section: Participantsmentioning

confidence: 99%

Early dysfunction of functional connectivity in healthy elderly with subjective memory complaints

Bajo

Castellanos

López

et al. 2011

AGE

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It is still an open question whether subjective memory complaints (SMC) can actually be considered to be clinically relevant predictors for the development of an objective memory impairment and even dementia. There is growing evidence that suggests that SMC are associated with an increased risk of dementia and with the presence of biological correlates of early Alzheimer's disease. In this paper, in order to shed some light on this issue, we try to discern whether subjects with SMC showed a different profile of functional connectivity compared with subjects with mild cognitive impairment (MCI) and healthy elderly subjects. In the present study, we compare the degree of synchronization of brain signals recorded with magnetoencephalography between three groups of subjects (56 in total): 19 with MCI, 12 with SMC and 25 healthy controls during a memory task. Synchronization likelihood, an index based on the theory of nonlinear dynamical systems, was used to measure functional connectivity. Briefly, results show that subjects with SMC have a very similar pattern of connectivity to control group, but on average, they present a lower synchronization value. These results could indicate that SMC are representing an initial stage with a hypo-synchronization (in comparison with the control group) where the brain system is still not compensating for the failing memory networks, but behaving as controls when compared with the MCI subjects.

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Spatio-temporal patterns of brain magnetic activity during a memory task in Alzheimer's disease

Cited by 58 publications

References 18 publications

The Hippocampus and Memory of Verbal and Pictorial Material

The Hippocampus and Memory of Verbal and Pictorial Material

The use of neuroimaging to study behavior in patients with epilepsy

Early dysfunction of functional connectivity in healthy elderly with subjective memory complaints

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