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Billig AJ, Lad M, Sedley W, Griffiths TD. The hearing hippocampus. Prog Neurobiol 2022; 218:102326. [PMID: 35870677 PMCID: PMC10510040 DOI: 10.1016/j.pneurobio.2022.102326] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/08/2022] [Accepted: 07/18/2022] [Indexed: 11/17/2022]
Abstract
The hippocampus has a well-established role in spatial and episodic memory but a broader function has been proposed including aspects of perception and relational processing. Neural bases of sound analysis have been described in the pathway to auditory cortex, but wider networks supporting auditory cognition are still being established. We review what is known about the role of the hippocampus in processing auditory information, and how the hippocampus itself is shaped by sound. In examining imaging, recording, and lesion studies in species from rodents to humans, we uncover a hierarchy of hippocampal responses to sound including during passive exposure, active listening, and the learning of associations between sounds and other stimuli. We describe how the hippocampus' connectivity and computational architecture allow it to track and manipulate auditory information - whether in the form of speech, music, or environmental, emotional, or phantom sounds. Functional and structural correlates of auditory experience are also identified. The extent of auditory-hippocampal interactions is consistent with the view that the hippocampus makes broad contributions to perception and cognition, beyond spatial and episodic memory. More deeply understanding these interactions may unlock applications including entraining hippocampal rhythms to support cognition, and intervening in links between hearing loss and dementia.
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Affiliation(s)
| | - Meher Lad
- Translational and Clinical Research Institute, Newcastle University Medical School, Newcastle upon Tyne, UK
| | - William Sedley
- Translational and Clinical Research Institute, Newcastle University Medical School, Newcastle upon Tyne, UK
| | - Timothy D Griffiths
- Biosciences Institute, Newcastle University Medical School, Newcastle upon Tyne, UK; Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, UK; Human Brain Research Laboratory, Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, USA
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2
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Colnaghi S, Beltrami G, Poloni G, Pichiecchio A, Bastianello S, Galimberti CA, Versino M. Parahippocampal Involvement in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis: A Proof of Concept from Memory-Guided Saccades. Front Neurol 2017; 8:595. [PMID: 29163352 PMCID: PMC5681931 DOI: 10.3389/fneur.2017.00595] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 10/23/2017] [Indexed: 02/04/2023] Open
Abstract
Objective Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) may involve extrahippocampal areas of structural damage and dysfunction. The accuracy of medium-term spatial memory can be tested by memory-guided saccades (MGS) to evaluate a functional impairment of the parahippocampal cortex (PHC), while voxel-based morphometry (VBM) analysis can be used to detect a structural damage of the latter region. Methods MGS with 3- and 30-s memorization delays were compared between 7 patients affected by right MTLE-HS (r-MTLE-HS), 6 patients affected by left MTLE-HS, and 13 healthy controls. The same subjects underwent brain MRI for a VBM analysis. Correlation analysis was performed between the results of VBM and MGS and with patients’ clinical data. Results Right MTLE-HS patients showed impaired accuracy of leftward MGS with a 30-s memorization delay; their gray-matter volume was reduced in the right hippocampus and inferior temporal gyrus, and bilaterally in the cerebellum. Left MTLE-HS patients had normal MGS accuracy; their gray-matter volume was reduced in the left hippocampus, in the right-inferior temporal gyrus and corpus callosus, and bilaterally in the insular cortex and in the cerebellum. The difference between right and left parahippocampal volumes correlated with MGS accuracy, while right and left hippocampal volumes did not. Hippocampal and parahippocampal volume did not correlate with clinical variables such as febrile seizures, age at disease onset, disease duration, and seizure frequency. Conclusion MGS abnormalities suggested the functional involvement of the right PHC in patients with r-MTLE-HS, supporting a right lateralization of spatial memory control and showing a relation between functional impairment and degree of atrophy.
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Affiliation(s)
- Silvia Colnaghi
- Laboratory of Neuro-otology and Neuro-ophtalmology, Fondazione Istituto Neurologico Nazionale Casimiro Mondino (IRCCS), Pavia, Italy.,Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy
| | - Giorgio Beltrami
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
| | - Guy Poloni
- Neuroradiology Department, Fondazione Istituto Neurologico Nazionale Casimiro Mondino (IRCCS), Pavia, Italy
| | - Anna Pichiecchio
- Neuroradiology Department, Fondazione Istituto Neurologico Nazionale Casimiro Mondino (IRCCS), Pavia, Italy
| | - Stefano Bastianello
- Neuroradiology Department, Fondazione Istituto Neurologico Nazionale Casimiro Mondino (IRCCS), Pavia, Italy.,Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Carlo Andrea Galimberti
- Epilepsy Centre, Fondazione Istituto Neurologico Nazionale Casimiro Mondino (IRCCS), Pavia, Italy
| | - Maurizio Versino
- Laboratory of Neuro-otology and Neuro-ophtalmology, Fondazione Istituto Neurologico Nazionale Casimiro Mondino (IRCCS), Pavia, Italy.,Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
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3
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Thomas E, Snyder PJ, Pietrzak RH, Maruff P. Behavior at the Choice Point: Decision Making in Hidden Pathway Maze Learning. Neuropsychol Rev 2014; 24:514-36. [DOI: 10.1007/s11065-014-9272-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 09/15/2014] [Indexed: 10/24/2022]
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4
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Hocking J, Thomas HJ, Dzafic I, Williams RJ, Reutens DC, Spooner DM. Disentangling the cognitive components supporting Austin Maze performance in left versus right temporal lobe epilepsy. Epilepsy Behav 2013; 29:485-91. [PMID: 24120029 DOI: 10.1016/j.yebeh.2013.08.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 08/19/2013] [Accepted: 08/22/2013] [Indexed: 10/26/2022]
Abstract
Neuropsychological tests requiring patients to find a path through a maze can be used to assess visuospatial memory performance in temporal lobe pathology, particularly in the hippocampus. Alternatively, they have been used as a task sensitive to executive function in patients with frontal lobe damage. We measured performance on the Austin Maze in patients with unilateral left and right temporal lobe epilepsy (TLE), with and without hippocampal sclerosis, compared to healthy controls. Performance was correlated with a number of other neuropsychological tests to identify the cognitive components that may be associated with poor Austin Maze performance. Patients with right TLE were significantly impaired on the Austin Maze task relative to patients with left TLE and controls, and error scores correlated with their performance on the Block Design task. The performance of patients with left TLE was also impaired relative to controls; however, errors correlated with performance on tests of executive function and delayed recall. The presence of hippocampal sclerosis did not have an impact on maze performance. A discriminant function analysis indicated that the Austin Maze alone correctly classified 73.5% of patients as having right TLE. In summary, impaired performance on the Austin Maze task is more suggestive of right than left TLE; however, impaired performance on this visuospatial task does not necessarily involve the hippocampus. The relationship of the Austin Maze task with other neuropsychological tests suggests that differential cognitive components may underlie performance decrements in right versus left TLE.
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Affiliation(s)
- Julia Hocking
- The University of Queensland, Centre for Advanced Imaging, St Lucia, Queensland, Australia.
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5
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Biagini G, D'Antuono M, Benini R, de Guzman P, Longo D, Avoli M. Perirhinal cortex and temporal lobe epilepsy. Front Cell Neurosci 2013; 7:130. [PMID: 24009554 PMCID: PMC3756799 DOI: 10.3389/fncel.2013.00130] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 08/01/2013] [Indexed: 12/30/2022] Open
Abstract
The perirhinal cortex—which is interconnected with several limbic structures and is intimately involved in learning and memory—plays major roles in pathological processes such as the kindling phenomenon of epileptogenesis and the spread of limbic seizures. Both features may be relevant to the pathophysiology of mesial temporal lobe epilepsy that represents the most refractory adult form of epilepsy with up to 30% of patients not achieving adequate seizure control. Compared to other limbic structures such as the hippocampus or the entorhinal cortex, the perirhinal area remains understudied and, in particular, detailed information on its dysfunctional characteristics remains scarce; this lack of information may be due to the fact that the perirhinal cortex is not grossly damaged in mesial temporal lobe epilepsy and in models mimicking this epileptic disorder. However, we have recently identified in pilocarpine-treated epileptic rats the presence of selective losses of interneuron subtypes along with increased synaptic excitability. In this review we: (i) highlight the fundamental electrophysiological properties of perirhinal cortex neurons; (ii) briefly stress the mechanisms underlying epileptiform synchronization in perirhinal cortex networks following epileptogenic pharmacological manipulations; and (iii) focus on the changes in neuronal excitability and cytoarchitecture of the perirhinal cortex occurring in the pilocarpine model of mesial temporal lobe epilepsy. Overall, these data indicate that perirhinal cortex networks are hyperexcitable in an animal model of temporal lobe epilepsy, and that this condition is associated with a selective cellular damage that is characterized by an age-dependent sensitivity of interneurons to precipitating injuries, such as status epilepticus.
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Affiliation(s)
- Giuseppe Biagini
- Laboratory of Experimental Epileptology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia Modena, Italy
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Ueda K, Fujiwara H, Miyata J, Hirao K, Saze T, Kawada R, Fujimoto S, Tanaka Y, Sawamoto N, Fukuyama H, Murai T. Investigating association of brain volumes with intracranial capacity in schizophrenia. Neuroimage 2009; 49:2503-8. [PMID: 19770046 DOI: 10.1016/j.neuroimage.2009.09.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 08/27/2009] [Accepted: 09/02/2009] [Indexed: 10/20/2022] Open
Abstract
Intracranial volume (ICV) is usually treated as a global or nuisance covariate in almost all volumetric studies of schizophrenia. However, validation for this analytic method has seldom been accomplished. In this study, we aimed to determine the effects of ICV on gray matter (GM) and white matter (WM) volumes. Sixty-three patients with schizophrenia and sixty normal controls were recruited; and high resolution T1 weighted images were obtained by 3T-MRI. After segmentation and normalization of the images into GM, WM, and cerebrospinal fluid (CSF), multiple regression analyses of global GM and WM volumes were performed using explanatory variables such as diagnosis, ICV, and diagnosis-ICV interaction. In addition, associations between regional GM and WM volumes with ICV were also investigated using voxel-based morphometry (VBM). No significant interaction between diagnosis and ICV was found for global GM volume, whereas interactions were detected in restricted GM areas using VBM. On the other hand, an interaction between ICV and diagnosis was found in WM not only for regional volumes, but also for global WM volume. The regression slope of global WM volumes against ICV was steeper in patients with schizophrenia than in healthy controls. These results imply that ICV should be carefully evaluated in the analyses of volumetric studies of schizophrenia, especially when analyzing WM volumes.
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Affiliation(s)
- Keita Ueda
- Department of Neuropsychiatry, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
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7
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Mechanic-Hamilton D, Korczykowski M, Yushkevich PA, Lawler K, Pluta J, Glynn S, Tracy JI, Wolf RL, Sperling MR, French JA, Detre JA. Hippocampal volumetry and functional MRI of memory in temporal lobe epilepsy. Epilepsy Behav 2009; 16:128-38. [PMID: 19674939 PMCID: PMC2749903 DOI: 10.1016/j.yebeh.2009.07.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 06/25/2009] [Accepted: 07/05/2009] [Indexed: 10/20/2022]
Abstract
This study examined the utility of structural and functional MRI at 1.5 and 3T in the presurgical evaluation and prediction of postsurgical cognitive outcome in temporal lobe epilepsy (TLE). Forty-nine patients undergoing presurgical evaluation for temporal lobe (TL) resection and 25 control subjects were studied. Patients completed standard presurgical evaluations, including the intracarotid amobarbital test (IAT) and neuropsychological testing. During functional imaging, subjects performed a complex visual scene-encoding task. High-resolution structural MRI scans were used to quantify hippocampal volumes. Both structural and functional imaging successfully lateralized the seizure focus and correlated with IAT memory lateralization, with improvement for functional imaging at 3T as compared with 1.5 T. Ipsilateral structural and functional MRI data were related to cognitive outcome, and greater functional asymmetry was related to earlier age at onset. These findings support continued investigation of the utility of MRI and fMRI in the presurgical evaluation of TLE.
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Affiliation(s)
- Dawn Mechanic-Hamilton
- Center for Functional Neuroimaging, University of Pennsylvania,Department of Psychology, Drexel University
| | | | | | - Kathy Lawler
- Department of Neurology, University of Pennsylvania
| | - John Pluta
- Center for Functional Neuroimaging, University of Pennsylvania
| | - Simon Glynn
- Center for Functional Neuroimaging, University of Pennsylvania,Department of Neurology, University of Pennsylvania
| | | | | | | | | | - John A. Detre
- Center for Functional Neuroimaging, University of Pennsylvania,Department of Neurology, University of Pennsylvania,Department of Radiology, University of Pennsylvania
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Bengner T, Siemonsen S, Stodieck S, Fiehler J. T2 relaxation time correlates of face recognition deficits in temporal lobe epilepsy. Epilepsy Behav 2008; 13:670-7. [PMID: 18722550 DOI: 10.1016/j.yebeh.2008.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 08/03/2008] [Accepted: 08/07/2008] [Indexed: 11/15/2022]
Abstract
This study explored structural correlates of immediate and delayed face recognition in 22 nonsurgical patients with nonlesional, unilateral mesial temporal lobe epilepsy (TLE, 10 left/12 right). We measured T2 relaxation time bilaterally in the hippocampus, the amygdala, and the fusiform gyrus. Apart from raised T2 values in the ipsilateral hippocampus, we found increased T2 values in the ipsilateral amygdala. Patients with right TLE exhibited impaired face recognition as a result of a decrease from immediate to delayed recognition. Higher T2 values in the right than left fusiform gyrus or hippocampus were related to worse immediate face recognition, but did not correlate with 24-hour face recognition. These preliminary results indicate that structural changes in the fusiform gyrus and hippocampus may influence immediate face recognition deficits, but have no linear influence on long-term face recognition in TLE. We suggest that long-term face recognition depends on a right hemispheric network encompassing structures outside the temporal lobe.
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Affiliation(s)
- Thomas Bengner
- Evangelisches Krankenhaus Alsterdorf gGmbH, Abteilung für Neurologie und Epileptologie, Hamburg, Germany.
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9
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McDonald CR. The use of neuroimaging to study behavior in patients with epilepsy. Epilepsy Behav 2008; 12:600-11. [PMID: 18078790 PMCID: PMC2702661 DOI: 10.1016/j.yebeh.2007.10.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Accepted: 10/31/2007] [Indexed: 10/22/2022]
Abstract
Structural and functional neuroimaging continues to play an increasing role in the presurgical evaluation of patients with epilepsy. In addition to its value in 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 extratemporal epilepsy 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, and their strengths and limitations for understanding behavior in epilepsy are assessed. 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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Affiliation(s)
- Carrie R. McDonald
- Department of Psychiatry, University of California, San Diego, Multimodal Imaging Laboratory, University of California, San Diego
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10
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Thalamic atrophy and cognition in unilateral temporal lobe epilepsy. J Int Neuropsychol Soc 2008; 14:384-93. [PMID: 18419837 DOI: 10.1017/s1355617708080399] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Revised: 12/14/2007] [Accepted: 12/14/2007] [Indexed: 11/07/2022]
Abstract
This study examined quantitative magnetic resonance volumes of the thalamus and hippocampus and determined their relationship with cognitive function and clinical seizure characteristics in a sample of 46 unilateral temporal lobe epilepsy (TLE) subjects (20 left and 26 right) and 29 controls. The hippocampus and thalamus exhibited different patterns of volume abnormality, different associations with clinical seizure characteristics, and different patterns of relationship with cognitive measures. Hippocampal volume reduction was primarily ipsilateral to the seizure focus, and thalamic volume reduction was bilateral. Ipsilateral hippocampal volume was significantly correlated with both early neurodevelopmental features (age of seizure onset) and disease characteristics (duration of epilepsy), whereas thalamus integrity was related only to disease variables. Hippocampal volume showed a selective association with verbal memory performance. In contrast, both left and right thalamic volumes were significantly correlated with performance on both memory and nonmemory cognitive domains. These findings underscore the importance of thalamic atrophy in chronic TLE and its potential implications for cognition.
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11
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Bengner T, Malina T, Lindenau M, Voges B, Goebell E, Stodieck S. Face memory in MRI-positive and MRI-negative temporal lobe epilepsy. Epilepsia 2007; 47:1904-14. [PMID: 17116031 DOI: 10.1111/j.1528-1167.2006.00811.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE Effects of MRI-positive (MRI(+)) as compared to MRI-negative (MRI(-)) temporal lobe epilepsy (TLE) on face memory are not yet known. METHODS We studied 24 MRI(-) (11 right/13 left) and 20 MRI(+) (13 right/7 left) TLE patients, 12 generalized epilepsy patients, and 12 healthy subjects undergoing diagnostic workup with 24-72-h Video-EEG-monitoring. Twenty faces were shown, and had to be recognized from 40 faces immediately and after a 24-h delay. RESULTS MRI(+) and MRI(-) right TLE (RTLE) patients showed deficits in face recognition compared to controls or generalized epilepsy, consistent with right temporal lobe dominance for face recognition. MRI(+) RTLE patients had deficits in both immediate and delayed recognition, while MRI(-) RTLE patients showed delayed recognition deficits only. The RTLE groups showed comparable delayed recognition deficits. Separate analyses in which the MRI(+) group included patients with hippocampal sclerosis only, did not alter results. Furthermore, MRI(-) RTLE had a worse delayed recognition than MRI(-) left TLE (LTLE). On the other hand, MRI(+) RTLE did not differ from MRI(+) LTLE in delayed recognition. Combining MRI(-) and MRI(+) TLE groups, we found differences between RTLE and LTLE in delayed, but not immediate face recognition. CONCLUSIONS Our results suggest that a delayed recognition condition might be superior to immediate recognition tests in detecting face memory deficits in MRI(-) RTLE patients. This might explain why former studies in preoperative patients did not observe an immediate face recognition dominance of the right temporal lobe when combining MRI(-) and MRI(+) TLE patients. Our data further point to an important role of the right mesial temporal region in face recognition in TLE.
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Affiliation(s)
- Thomas Bengner
- Epilepsy Center Hamburg, Protestant Hospital Alsterdorf, Hamburg, Germany.
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12
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Colnaghi S, Arbasino C, Beltrami G, Galimberti CA, Cosi V, Versino M. Memory guided saccades in mesial temporal lobe epilepsy with hippocampal sclerosis. Clin Neurophysiol 2006; 117:2392-8. [PMID: 16978920 DOI: 10.1016/j.clinph.2006.07.135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 06/29/2006] [Accepted: 07/04/2006] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) may involve extrahippocampal areas of structural and functional damage. The incidence and the features of this damage are still a matter of debate and vary depending on the method applied. Memory guided saccades (MGSs) with a memorization delay longer than 20s can be used reliably to evaluate the parahippocampal cortex. METHODS MGSs with 3 and 30s memorization delays were recorded with the search coil technique in six patients affected by right MTLE-HS, and in 13 healthy controls. RESULTS The patients were not able to reduce the MGSs residual amplitude error after the first saccade with a 30s memorization delay. This finding was more evident with leftward saccades. CONCLUSIONS MGS abnormalities suggested the functional involvement of the right parahippocampal cortex in most of the patients with MTLE-HS, and this supports the clinical and anatomopathological heterogeneity of the disease. SIGNIFICANCE MGSs can be used in patients with right MTLE-HS to detect a possible functional involvement of the ipsilateral parahippocampal cortex.
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Affiliation(s)
- S Colnaghi
- Laboratorio Movimenti Oculari, Fondazione Istituto Neurologico C. Mondino IRCCS, Dipartimento di Scienze Neurologiche, Università degli Studi di Pavia, Italy.
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13
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Oyegbile TO, Bhattacharya A, Seidenberg M, Hermann BP. Quantitative MRI biomarkers of cognitive morbidity in temporal lobe epilepsy. Epilepsia 2006; 47:143-52. [PMID: 16417542 DOI: 10.1111/j.1528-1167.2006.00380.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To determine the relation between neuropsychological morbidity, quantitative magnetic resonance imaging (MRI) measures of whole brain structure, and clinical seizure factors reflecting epilepsy cause, course, and treatment. METHODS Quantitative MRI measurements of total (whole brain) cerebrospinal fluid (CSF) and gray- and white-matter volumes and clinical seizure features were examined in relation to summary indices of cognitive morbidity in 96 patients with temporal lobe epilepsy. MRI volumes were adjusted for intracranial volume (ICV), and cognitive scores were adjusted for age, education, and gender, based on a sample of 82 healthy controls. RESULTS Whole-brain volumes (gray, white, and CSF) were abnormal in chronic temporal lobe epilepsy patients compared with controls and were related significantly to neuropsychological morbidity, especially total CSF. Statistical modeling demonstrated that markers of total atrophy (CSF) was the primary mediator of the relation between clinical seizure variables and neuropsychological morbidity. CONCLUSIONS Quantitative measurements of overall brain abnormality (atrophy) in temporal lobe epilepsy are clinically meaningful markers that are associated with increased cognitive morbidity. These biomarkers appear to mediate the adverse effects of some clinical seizure variables on cognition.
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Affiliation(s)
- Tayo O Oyegbile
- Department of Neurology, University of Wisconsin-Madison, Madison, Wisconsin 53792, USA
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Hannesson DK, Howland JG, Pollock M, Mohapel P, Wallace AE, Corcoran ME. Anterior perirhinal cortex kindling produces long-lasting effects on anxiety and object recognition memory. Eur J Neurosci 2005; 21:1081-90. [PMID: 15787713 DOI: 10.1111/j.1460-9568.2005.03938.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Temporal lobe epilepsy (TLE) is frequently accompanied by memory impairments and, although their bases are unknown, most research has focused on the hippocampus. The present study investigated the importance of another medial temporal lobe structure, the perirhinal cortex (Prh), in changes in memory in TLE using kindling as a model. Rats were kindled twice daily with anterior Prh stimulation until three fully generalized seizures were evoked. Beginning 7 days later and on successive days, rats were tested in an elevated plus maze, a large circular open field, an open field object exploration task and a delayed-match-to-place task in a water maze in order to assess anxiety-related and exploratory behaviour, object recognition memory and spatial cognition. Kindling increased anxiety-related behaviour in both the elevated plus and open field mazes and disrupted spontaneous object recognition but spared all other behaviours tested. These results are consistent with other findings indicating a greater role for the Prh in object memory and emotional behaviour than in spatial memory and contrast with the selective disruption of spatial memory produced by dorsal hippocampal kindling. The site-selectivity of the behavioural disruptions produced by kindling indicates that such effects are probably mediated by changes particular to the site of seizure initiation rather than to changes in the characteristic circuitry activated by limbic seizure generalization. Further investigation of the behavioural effects of Prh kindling may be useful for studying the mechanisms of mnemonic and affective dysfunction associated with TLE and offer insights into bases for variability in such dysfunction across patients.
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Affiliation(s)
- D K Hannesson
- Canadian Centre for Behavioural Neuroscience, Department of Psychology and Neuroscience, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
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