Hemispheric Lateralization Interrupted: Material-Specific Memory Deficits in Temporal Lobe Epilepsy

Willment, Kim; Golby, Alexandra J.

doi:10.3389/fnhum.2013.00546

Cited by 68 publications

(30 citation statements)

References 127 publications

(185 reference statements)

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“…Interestingly, using multivoxel pattern analysis, one previous study found that the activity patterns of specific memories were detected in a contralateral HIP, but not a sclerotic HIP, in patients with TLE. 26 Similarly, the present study demonstrated that activations in the contralateral, but not the ipsilateral, HIP were correlated with the memory performance of MTLR patients. It seems that the ipsilateral posterior HIP is more strongly related to other clinical variables, including the duration of illness and age at seizure onset, rather than individual memory capacity.…”

Section: Activations In Hippocampus Ipsilateral To Resection Sidesupporting

confidence: 75%

“…According to the material-specific memory model, verbal memory is generally more dependent on the left (dominant hemisphere) medial temporal lobe (MTL) structures while visual memory is more dependent on the right MTL structures. 26 However, in the present study, the contralateral right HIP performed the role of verbal memory function of the left HIP in patients who underwent left HIP resection. In contrast, the contralateral left HIP performed the role of the visual memory function of the right HIP in patients who underwent right HIP resection.…”

Section: Activations In Hippocampus Contralateral To Resection Sidementioning

confidence: 54%

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Neural basis of episodic memory in the intermediate term after medial temporal lobe resection

Jeong

Lee²,

Kim

et al. 2019

Journal of Neurosurgery

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OBJECTIVEHow the brain supports intermediate-term preservation of memory in patients who have undergone unilateral medial temporal lobe resection (MTLR) has not yet been demonstrated. To understand the neural basis of episodic memory in the intermediate term after surgery for temporal lobe epilepsy (TLE), the authors investigated the relationship between the activation of the hippocampus (HIP) during successful memory encoding and individual memory capacity in patients who had undergone MTLR. They also compared hippocampal activation with other parameters, including structural volumes of the HIP, duration of illness, and age at seizure onset.METHODSThirty-five adult patients who had undergone unilateral MTLR at least 1 year before recruiting and who had a favorable seizure outcome were enrolled (17 left MTLR, 18 right MTLR; mean follow-up 6.31 ± 2.72 years). All patients underwent a standardized neuropsychological examination of memory function and functional MRI scanning with a memory-encoding paradigm of words and figures. Activations of the HIP during successful memory encoding were calculated and compared with standard neuropsychological memory scores, hippocampal volumes, and other clinical variables.RESULTSGreater activation in the HIP contralateral to the side of the resection was related to higher postoperative memory scores and greater postoperative memory improvement than the preoperative baseline in both patient groups. Specifically, postoperative verbal memory performance was positively correlated with contralateral right hippocampal activation during word encoding in the left-sided surgery group. In contrast, postoperative visual memory performance was positively correlated with contralateral left hippocampal activation during figure encoding in the right-sided surgery group. Activation of the ipsilateral remnant HIP was not correlated with any memory scores or volumes of the HIP; however, it had a negative correlation with the seizure-onset age and positive correlation with the duration of illness in both patient groups.CONCLUSIONSFor the first time, a neural basis that supports effective intermediate-term episodic memory after unilateral MTLR has been characterized. The results provide evidence that engagement of the HIP contralateral rather than ipsilateral to the side of resection is responsible for effective memory function in the intermediate term (> 1 year) after surgery in patients who have undergone left MTLR and right MTLR. Engagement of the material-specific contralesional HIP, verbal memory in the left-sided surgery group, and visual memory in the right-sided surgery group were observed.

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Section: Activations In Hippocampus Ipsilateral To Resection Sidesupporting

confidence: 75%

Section: Activations In Hippocampus Contralateral To Resection Sidementioning

confidence: 54%

Neural basis of episodic memory in the intermediate term after medial temporal lobe resection

Jeong

Lee²,

Kim

et al. 2019

Journal of Neurosurgery

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“…Therefore, we hypothesized that hippocampal subfield volumes that were smaller in PBTS compared with TDC would correlate with episodic memory performance. Although verbal memory lateralization is not present in all individuals (Catani et al, ), lesion studies in adults (Saling et al, ) and children with epilepsy (Gleissner et al, ; Leunen et al, ) suggest that the left hemisphere plays a particularly important role in verbal memory in most individuals (for a review, see Saling, ; Willment & Golby, ). Based on this research, we expected that the left hippocampal subfields would have stronger associations with verbal memory in PBTS than the right subfields.…”

Section: Introductionmentioning

confidence: 99%

Smaller hippocampal subfield volumes predict verbal associative memory in pediatric brain tumor survivors

et al. 2017

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The developing hippocampus is highly sensitive to chemotherapy and cranial radiation treatments for pediatric cancers, yet little is known about the effects that cancer treatents have on specific hippocampal subfields. Here, we examined hippocampal subfield volumes in 29 pediatric brain tumor survivors treated with cranial radiation and chemotherapy, and 30 healthy developing children and adolescents. We also examined associations between hippocampal subfield volumes and short-term verbal memory. Hippocampal subfields (Cornus Ammonis (CA) 1, CA2-3, dentate gyrus (DG)-CA4, stratum radiatum-lacunosum-moleculare, and subiculum) were segmented using the Multiple Automatically Generated Templates for Different Brains automated segmentation algorithm. Neuropsychological assessment of short-term verbal associative memory was performed in a subset of brain tumor survivors (N = 11) and typically developing children (N = 16), using the Children's Memory Scale or Wechsler's Memory Scale-third edition. Repeated measures analysis of variance showed that pediatric brain tumor survivors had significantly smaller DG-CA4, CA1, CA2-3, and stratum radiatum-lacunosum-moleculare volumes compared with typically developing children. Verbal memory performance was positively related to DG-CA4, CA1, and stratum radiatum-lacunosum-moleculare volumes in pediatric brain tumor survivors. Unlike the brain tumor survivors, there were no associations between subfield volumes and memory in typically developing children and adolescents. These data suggest that specific subfields of the hippocampus may be vulnerable to brain cancer treatments, and may contribute to impaired episodic memory following brain cancer treatment in childhood.

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“…In up to 80% of TLE, epilepsy surgery can be curative (4), however, cognitive decline remains a significant complication of epilepsy surgery (5)(6)(7)(8)(9)(10). Early onset seizures interfere with the normal process of hemispheric lateralization (11) and may result in the reorganization of memory functions (12)(13)(14). In unilateral TLE, both the function of the contra-lateral MTL (hippocampal adequacy theory), and functional reserve of the ipsilateral hippocampus have been posited in the maintenance of post-operative memory functions (15).…”

Section: Introductionmentioning

confidence: 99%

A Guide to Designing a Memory fMRI Paradigm for Pre-surgical Evaluation in Temporal Lobe Epilepsy

Buck

Sidhu

2020

Front. Neurol.

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There has been increasing interest in the clinical and experimental use of memory functional Magnetic Resonance Imaging (fMRI). The 2017 American Academy of Neurology practice guidelines on the use of pre-surgical cognitive fMRI suggests that verbal memory fMRI could be used to lateralize memory functions in people with Temporal Lobe Epilepsy (TLE) and should be used to predict post-operative verbal memory outcome. There are however technical and methodological considerations, to optimize both the sensitivity and specificity of this imaging modality. Below we discuss these constraints and suggest recommendations to consider when designing a memory fMRI paradigm.

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Hemispheric Lateralization Interrupted: Material-Specific Memory Deficits in Temporal Lobe Epilepsy

Cited by 68 publications

References 127 publications

Neural basis of episodic memory in the intermediate term after medial temporal lobe resection

Neural basis of episodic memory in the intermediate term after medial temporal lobe resection

Smaller hippocampal subfield volumes predict verbal associative memory in pediatric brain tumor survivors

A Guide to Designing a Memory fMRI Paradigm for Pre-surgical Evaluation in Temporal Lobe Epilepsy

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