scholarly journals Decrements in Hippocampal Activity with Item Repetition during Continuous Recognition: An fMRI Study

2011 ◽  
Vol 23 (6) ◽  
pp. 1522-1532 ◽  
Author(s):  
Maki Suzuki ◽  
Jeffrey D. Johnson ◽  
Michael D. Rugg
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Temporal Cortex ◽  
Recognition Task ◽  
Posterior Cingulate Cortex ◽  
Memory Strength ◽  
Hippocampal Activity ◽  
Cortical Regions ◽  
Different Response ◽  
The Right

fMRI (1.5 mm isotropic voxels) was employed to investigate the relationship between hippocampal activity and memory strength in a continuous recognition task. While being scanned, subjects were presented with colored photographs that each appeared on four occasions. The requirements were to make one response when an item was presented for the first or the third time and to make a different response when an item appeared for the second or the fourth time. Consistent with prior findings, items presented for the first time elicited greater hippocampal and parahippocampal activity than repeated items. The activity elicited by repeated items declined linearly as a function of number of presentations (“graded” new > old effects). No medial-temporal lobe regions could be identified where activity elicited by repeated items exceeded that for new items or where activity elicited by repeated items increased with number of presentations. These findings are inconsistent with the proposal that retrieval-related hippocampal activity is positively correlated with memory strength. We also identified graded new > old effects in several cortical regions outside the medial-temporal lobe, including the left retrosplenial/posterior cingulate cortex and the right lateral occipito-temporal cortex. By contrast, graded old > new effects were evident in bilateral mid-intraparietal sulcus and precuneus.

scholarly journals Neural Correlates of Encoding Within- and Across-domain Inter-item Associations

2011 ◽  
Vol 23 (9) ◽  
pp. 2533-2543 ◽  
Author(s):  
Heekyeong Park ◽  
Michael D. Rugg
Keyword(s):  
Medial Temporal Lobe ◽  
Inferior Frontal Gyrus ◽  
Temporal Cortex ◽  
Recognition Task ◽  
Neural Correlates ◽  
Memory Effects ◽  
Pair Type ◽  
General Role ◽  
The Difference ◽  
Cortical Regions

The neural correlates of the encoding of associations between pairs of words, pairs of pictures, and word–picture pairs were compared. The aims were to determine, first, whether the neural correlates of associative encoding vary according to study material and, second, whether encoding of across- versus within-material item pairs is associated with dissociable patterns of hippocampal and perirhinal activity, as predicted by the “domain dichotomy” hypothesis of medial temporal lobe function. While undergoing fMRI scanning, subjects (n = 24) were presented with the three classes of study pairs, judging which of the denoted objects fit into the other. Outside of the scanner, subjects then undertook an associative recognition task, discriminating between intact study pairs, rearranged pairs comprising items that had been presented on different study trials, and unstudied item pairs. The neural correlates of successful associative encoding—subsequent associative memory effects—were operationalized as the difference in activity between study pairs correctly judged intact versus pairs incorrectly judged rearranged on the subsequent memory test. Pair type–independent subsequent memory effects were evident in the left inferior frontal gyrus (IFG) and the hippocampus. Picture–picture pairs elicited material-selective effects in regions of fusiform cortex that were also activated to a greater extent on picture trials than on word trials, whereas word–word pairs elicited material-selective subsequent memory effects in left lateral temporal cortex. Contrary to the domain-dichotomy hypothesis, neither hippocampal nor perirhinal subsequent memory effects differed depending on whether they were elicited by within- versus across-material study pairs. It is proposed that the left IFG plays a domain-general role in associative encoding, that associative encoding can also be facilitated by enhanced processing in material-selective cortical regions, and that the hippocampus and perirhinal cortex contribute equally to the formation of inter-item associations, regardless of whether the items belong to the same or to different processing domains.

scholarly journals Localization of Syntactic and Semantic Brain Responses using Magnetoencephalography

2007 ◽  
Vol 19 (7) ◽  
pp. 1193-1205 ◽  
Author(s):  
Elisabet Service ◽  
Päivi Helenius ◽  
Sini Maury ◽  
Riitta Salmelin
Keyword(s):  
Temporal Lobe ◽  
Semantic Processing ◽  
Sentence Comprehension ◽  
Right Hemisphere ◽  
Temporal Cortex ◽  
Word Class ◽  
Sentence Reading ◽  
Word Onset ◽  
Semantic Errors ◽  
The Right

Electrophysiological methods have been used to study the temporal sequence of syntactic and semantic processing during sentence comprehension. Two responses associated with syntactic violations are the left anterior negativity (LAN) and the P600. A response to semantic violation is the N400. Although the sources of the N400 response have been identified in the left (and right) temporal lobe, the neural signatures of the LAN and P600 have not been revealed. The present study used magnetoencephalography to localize sources of syntactic and semantic activation in Finnish sentence reading. Participants were presented with sentences that ended in normally inf lected nouns, nouns in an unacceptable case, verbs instead of nouns, or nouns that were correctly inflected but made no sense in the context. Around 400 msec, semantically anomalous last words evoked strong activation in the left superior temporal lobe with significant activation also for word class errors (N400). Weaker activation was seen for the semantic errors in the right hemisphere. Later, 600-800 msec after word onset, the strongest activation was seen to word class and morphosyntactic errors (P600). Activation was significantly weaker to semantically anomalous and correct words. The P600 syntactic activation was localized to bilateral sources in the temporal lobe, posterior to the N400 sources. The results suggest that the same general region of the superior temporal cortex gives rise to both LAN and N400 with bilateral reactivity to semantic manipulation and a left hemisphere effect to syntactic manipulation. The bilateral P600 response was sensitive to syntactic but not semantic factors.

Simultaneous Electroencephalographic and Electocorticographic Recordings of Lateralized Periodic Discharges in Temporal Lobe Epilepsy

2020 ◽  
pp. 155005942097226
Author(s):  
Ayumi Sakata ◽  
Nobutaka Mukae ◽  
Takato Morioka ◽  
Shunya Tanaka ◽  
Takafumi Shimogawa ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Chronic Conditions ◽  
Medial Temporal Lobe ◽  
Temporal Cortex ◽  
Temporal Region ◽  
Pathophysiological Mechanism ◽  
Periodic Discharges ◽  
Pathological Conditions ◽  
Eeg Pattern

Objective Lateralized periodic discharges (LPDs), which constitute an abnormal electroencephalographic (EEG) pattern, are most often observed in critically ill patients with acute pathological conditions, and are less frequently observed in chronic conditions such as focal epilepsies, including temporal lobe epilepsy (TLE). Here we aim to explore the pathophysiological mechanism of LPD in TLE. Methods We retrospectively selected 3 patients with drug-resistant TLE who simultaneously underwent EEG and electrocorticography (ECoG) and demonstrated LPDs. We analyzed the correlation between the EEG and ECoG findings. Results In patients 1 and 2, LPDs were recorded in the temporal region of the scalp during the interictal periods, when repeated spikes followed by slow waves (spike-and-wave complexes; SWs) and periodic discharges (PDs) with amplitudes of >600 to 800 µV appeared in the lateral temporal lobe over a cortical area of >10 cm2. In patient 3, when the ictal discharges persisted and were confined to the medial temporal lobe, repeated SWs were provoked on the lateral temporal lobe. When repeated SWs with amplitudes of >800 µV appeared in an area of the lateral temporal lobe of >10 cm2, the corresponding EEG discharges appeared on the temporal scalp. Conclusions LPDs in patients with TLE originate from repeated SWs and PDs of the lateral temporal lobe, which might represent a highly irritable state of the lateral temporal cortex during both interictal and ictal periods.

scholarly journals An Exploratory Study of the Relationship between Face Recognition Memory and the Volume of Medial Temporal Lobe Structures in Healthy Young Males

1998 ◽  
Vol 11 (1) ◽  
pp. 3-20 ◽  
Author(s):  
Clare E. Mackay ◽  
Neil Roberts ◽  
Andrew R. Mayes ◽  
John J. Downes ◽  
Jonathan K. Foster ◽  
...  
Keyword(s):  
Face Recognition ◽  
Recognition Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Multiple Comparisons ◽  
Cerebral Hemispheres ◽  
Parahippocampal Gyrus ◽  
Bonferroni Correction ◽  
Temporal Pole ◽  
The Right

A rigorous new methodology was applied to the study of structure function relationships in the living human brain. Face recognition memory (FRM) and other cognitive measures were made in 29 healthy young male subjects (mean age = 21.7 years) and related to volumetric measurements of their cerebral hemispheres and of structures in their medial temporal lobes, obtained using the Cavalieri method in combination with high resolution Magnetic Resonance Imaging (MRI. Greatest proportional variability in volumes was found for the lateral ventricles (57%) for the cerebral hemispheres (8%) in the mean volumes of the hippocampus, parahippocampal gyrus, amygdala, caudate nucleus, temporal pole and temporal lobe on the right and left sides of the brain. The volumes of the right and left parahippocampal gyrus, temporal pole, temporal lobe, and left hippocampus were, prior to application of the Bonferroni correction to take account of 12 multiple comparisons, significantly correlated with the volume of the corresponding hemisphere (p< 0.05). The volumes of all structures were highly correlated (p< 0.0002 for all comparisons) between the two cerebral hemispheres. There were no positive relationships between structure volumes and FRM score. However, the volume of the right amygdala was, prior to application of the Bonferroni correction to take account of 38~multiple comparisons, found to be significantly smaller in the five most consistent high scorers compared to the five most consistent low scorers (t= 2.77,p= 0.025). The implications for possible relationships between healthy medial temporal lobe structures and memory are discussed.

scholarly journals Distinct Cortical Anatomy Linked to Subregions of the Medial Temporal Lobe Revealed by Intrinsic Functional Connectivity

2008 ◽  
Vol 100 (1) ◽  
pp. 129-139 ◽  
Author(s):  
Itamar Kahn ◽  
Jessica R. Andrews-Hanna ◽  
Justin L. Vincent ◽  
Abraham Z. Snyder ◽  
Randy L. Buckner
Keyword(s):  
Functional Connectivity ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Temporal Cortex ◽  
Memory System ◽  
Retrosplenial Cortex ◽  
The Body ◽  
Parallel Pathways ◽  
Ventral Medial Prefrontal Cortex ◽  
Adjacent Structures

The hippocampus and adjacent cortical structures in the medial temporal lobe (MTL) contribute to memory through interactions with distributed brain areas. Studies of monkey and rodent anatomy suggest that parallel pathways converge on distinct subregions of the MTL. To explore the cortical areas linked to subregions of the MTL in humans, we examined cortico-cortical and hippocampal-cortical correlations using high-resolution, functional connectivity analysis in 100 individuals. MTL seed regions extended along the anterior to posterior axis and included hippocampus and adjacent structures. Results revealed two separate brain pathways that correlated with distinct subregions within the MTL. The body of the hippocampus and posterior parahippocampal cortex correlated with lateral parietal cortex, regions along the posterior midline including posterior cingulate and retrosplenial cortex, and ventral medial prefrontal cortex. By contrast, anterior hippocampus and the perirhinal/entorhinal cortices correlated with distinct regions in the lateral temporal cortex extending into the temporal pole. The present results are largely consistent with known connectivity in the monkey and provide a novel task-independent dissociation of the parallel pathways supporting the MTL memory system in humans. The cortical pathways include regions that have undergone considerable areal expansion in humans, providing insight into how the MTL memory system has evolved to support a diverse array of cognitive domains.

Access to the Posterior Medial Temporal Lobe Structures in the Surgical Treatment of Temporal Lobe Epilepsy

Neurosurgery ◽  
1984 ◽  
Vol 15 (5) ◽  
pp. 667-671 ◽  
Author(s):  
Dennis D. Spencer ◽  
Susan S. Spencer ◽  
Richard H. Mattson ◽  
Peter D. Williamson ◽  
Robert A. Novelly
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Temporal Cortex ◽  
En Bloc Resection ◽  
Bloc Resection ◽  
En Bloc ◽  
Visual Spatial ◽  
Temporal Horn ◽  
Inferior Longitudinal Fasciculus ◽  
Complex Partial Epilepsy

Abstract The authors describe a surgical technique that allows access to the posterior temporal horn of the lateral ventricle with preservation of the most functional lateral temporal cortex. Development of the technique was stimulated by the need to resect posteromedial temporal lobe structures in patients with intractable complex partial epilepsy and well-identified unilateral posterior hippocampal foci. This technique has also been of value in the resection of some lateral ventricular and posteromedial temporal lobe masses. The operation consists of three steps. No more than 4.5 cm of the anterolateral temporal lobe is removed en bloc such that the most anterior aspect of the temporal horn is entered. An incision is carried from the floor of the temporal horn through the inferior longitudinal fasciculus to the middle fossa dura mater and posteriorally into the lateral ventricular atrium. The lateral temporal cortex and white matter are then elevated with a self-retaining retractor. This exposes the posteromedial temporal horn or intraaxial mass for excision or allows en bloc resection of the entire hippocampus and medial temporal lobe structures while preserving the functional association areas of the lateral temporal cortex, including speech and visual spatial function.

scholarly journals Evidence Accumulation Modelling Reveals that Gaussian Noise Accounts for Inhibition of Return

2020 ◽  
Author(s):  
Tal Seidel Malkinson ◽  
Alexia Bourgeois ◽  
Nicolas Wattiez ◽  
Pierre Pouget ◽  
Paolo Bartolomeo
Keyword(s):  
Gaussian Noise ◽  
Inhibition Of Return ◽  
Response Times ◽  
Information Criterion ◽  
Model Parameters ◽  
Noise Parameter ◽  
Evidence Accumulation ◽  
Cortical Regions ◽  
Different Response ◽  
The Right

AbstractInhibition of return (IOR) refers to the slowing of response times (RTs) for stimuli repeated at previously inspected locations, as compared with novel ones. However, the exact processing stage(s) at which IOR occurs, and its nature across different response modalities, remain debated. We tested predictions on these issues originating from the FORTIOR model (fronto-parietal organization of response times in IOR; Seidel Malkinson & Bartolomeo, 2018), and from evidence accumulation models. We reanalysed RT data from a target-target IOR paradigm (Bourgeois et al.,2013a, 2013b) by using a LATER-like evidence accumulation model (Carpenter & Williams, 1995), to test the predictions of FORTIOR, and specifically whether IOR could occur at sensory/attentional stages of processing, or at stages of decision and action selection. We considered the following conditions: manual or saccadic response modality, before or after TMS perturbation over four cortical regions. Results showed that the Gaussian noise parameter best explained both manual and saccadic IOR, suggesting that in both response modalities IOR may result from slower accumulation of evidence for repeated locations. Additionally, across stimulated regions, TMS affected only manual RTs, lowering them equally in the conditions with repeated targets (Return) and non-repeated targets (Non-return). Accordingly, the modelling results show that TMS stimulation did not significantly alter the pattern between model parameters, with the Gaussian noise parameter remaining the parameter best explaining the Return - Non-return RT difference. Moreover, TMS over the right intra-parietal sulcus (IPS) perturbed IOR by shortening the Return RT. When directly testing this effect by modelling the TMS impact in the Return condition, the Bayesian information criterion of the Gaussian noise parameter was the smallest, but this effect did not reach significance. These results support the hypothesis that target-target IOR is a predominantly sensory/attentional phenomenon, and may be modulated by activity in fronto-parietal networks.

Left Transsylvian Transcisternal and Transinferior Insular Sulcus Approach for Resection of Uncohippocampal Tumor: 3-Dimensional Operative Video

2018 ◽  
Vol 15 (6) ◽  
pp. E79-E80 ◽  
Author(s):  
Juan C Fernandez-Miranda
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Anterior Segment ◽  
Temporal Cortex ◽  
Surgical Anatomy ◽  
Temporal Lobectomy ◽  
Temporal Region ◽  
3 Dimensional ◽  
Selective Amygdalohippocampectomy ◽  
Selective Approach

Abstract The medial temporal lobe can be divided in anterior, middle, and posterior segments. The anterior segment is formed by the uncus and hippocampal head, and it has extra and intraventricular structures. There are 2 main approaches to the uncohippocampal region, the anteromedial temporal lobectomy (Spencer's technique) and the transsylvian selective amygdalohippocampectomy (Yasargil's technique). In this video, we present the case of a 29-yr-old man with new onset of generalized seizures and a contrast-enhancing lesion in the left anterior segment of the medial temporal lobe compatible with high-grade glioma. He had a medical history of cervical astrocytoma at age 8 requiring craniospinal radiation therapy and ventriculoperitoneal shunt placement. The tumor was approached using a combined transsylvian transcisternal and transinferior insular sulcus approach to the extra and intraventricular aspects of the uncohippocampal region. It was resected completely, and the patient was neurologically intact after resection with no further seizures at 6-mo follow-up. The diagnosis was glioblastoma IDH-wild type, for which he underwent adjuvant therapy. Surgical anatomy and technical nuances of this approach are illustrated using a 3-dimensional video and anatomic dissections. The selective approach, when compared to an anteromedial temporal lobectomy, has the advantage of preserving the anterolateral temporal cortex, which is particularly relevant in dominant-hemisphere lesions, and the related fiber tracts, including the inferior fronto-occipital and inferior longitudinal fascicles, and most of the optic radiation fibers. The transsylvian approach, however, is technically and anatomically more challenging and potentially carries a higher risk of vascular injury and vasospasm. Page 1 and figures from Fernández-Miranda JC et al, Microvascular Anatomy of the Medial Temporal Region: Part 1: Its Application to Arteriovenous Malformation Surgery, Operative Neurosurgery, 2010, Volume 67, issue 3, ons237-ons276, by permission of the Congress of Neurological Surgeons (1:26-1:37 in video). Page 1 from Fernández-Miranda JC et al, Three-Dimensio-nal Microsurgical and Tractographic Anatomy of the White Matter of the Human Brain, Neurosurgery, 2008, Volume 62, issue suppl_3, SHC989-SHC1028, by permission of the Congress of Neurological Surgeons (1:54-1:56 in video).

scholarly journals Representations of local spatial information in the human medial temporal lobe during memory-guided navigation

2020 ◽  
Author(s):  
Shao-Fang Wang ◽  
Valerie A. Carr ◽  
Serra E. Favila ◽  
Jeremy N. Bailenson ◽  
Thackery I. Brown ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Spatial Information ◽  
Activity Patterns ◽  
Critical Role ◽  
Neural Representations ◽  
Parahippocampal Cortex ◽  
Pattern Similarity ◽  
Cortical Regions ◽  
Goal Directed Behavior

AbstractThe hippocampus (HC) and surrounding medial temporal lobe (MTL) cortical regions play a critical role in spatial navigation and episodic memory. However, it remains unclear how the interaction between the HC’s conjunctive coding and mnemonic differentiation contributes to neural representations of spatial environments. Multivariate functional magnetic resonance imaging (fMRI) analyses enable examination of how human HC and MTL cortical regions encode multidimensional spatial information to support memory-guided navigation. We combined high-resolution fMRI with a virtual navigation paradigm in which participants relied on memory of the environment to navigate to goal locations in two different virtual rooms. Within each room, participants were cued to navigate to four learned locations, each associated with one of two reward values. Pattern similarity analysis revealed that when participants successfully arrived at goal locations, activity patterns in HC and parahippocampal cortex (PHC) represented room-goal location conjunctions and activity patterns in HC subfields represented room-reward-location conjunctions. These results add to an emerging literature revealing hippocampal conjunctive representations during goal-directed behavior.

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