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Schizophrenia Bulletin 2003A central question in schizophrenia research is which brain abnormalities are independent of psychosis and which evolve before and after psychosis begins. This question... (Review)
Review
A review and new report of medial temporal lobe dysfunction as a vulnerability indicator for schizophrenia: a magnetic resonance imaging morphometric family study of the parahippocampal gyrus.
A central question in schizophrenia research is which brain abnormalities are independent of psychosis and which evolve before and after psychosis begins. This question can be addressed by longitudinal neuroimaging studies beginning in the prodrome, but at present there is only one published study. We reviewed the literature on structural brain imaging in persons with chronic and first episode schizophrenia, nonpsychotic persons at genetic high risk, and persons thought to be at risk for imminent psychosis ("prodromal" persons). Medial temporal lobe (MTL), especially hippocampal, volume alterations are among the most robust brain vulnerabilities for schizophrenia. Because verbal declarative memory (VDM) deficits are prominent and the parahippocampal gyrus (PHG) is considered to be centrally involved with the hippocampus in VDM processing, we analyzed PHG data from a family study of schizophrenia. Patients with schizophrenia and nonpsychotic relatives from "multiplex" families (families with multiple persons with schizophrenia) had significantly smaller right parahippocampal anterior (PHa) volumes than controls. Marginally significant findings were observed for the left PHa. Unexpectedly, relatives from "simplex" families (families with only one person with schizophrenia) had significantly larger PH posterior volumes than controls and did not differ from controls on PHa. Results provide some support for the hypothesis that the vulnerability to schizophrenia includes abnormal volumes of the PHG. These data provide additional support for the hypothesis that some MTL abnormalities in schizophrenia are independent of psychosis, at least in families with presumably high genetic loading. Implications of genetic risk studies for prodromal research are discussed.
Topics: Adult; Aged; Brain Mapping; Chronic Disease; Dominance, Cerebral; Female; Genetic Load; Hippocampus; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Magnetic Resonance Imaging; Male; Middle Aged; Neuropsychological Tests; Parahippocampal Gyrus; Phenotype; Reference Values; Risk; Schizophrenia; Schizotypal Personality Disorder; Temporal Lobe
PubMed: 14989416
DOI: 10.1093/oxfordjournals.schbul.a007048 -
Journal of Molecular Neuroscience : MN Sep 2015The aim of this study is to analyze cognitive impairment in amyotrophic lateral sclerosis (ALS). Forty-four participants matched for age, sex, and educational background...
ALFF Value in Right Parahippocampal Gyrus Acts as a Potential Marker Monitoring Amyotrophic Lateral Sclerosis Progression: a Neuropsychological, Voxel-Based Morphometry, and Resting-State Functional MRI Study.
The aim of this study is to analyze cognitive impairment in amyotrophic lateral sclerosis (ALS). Forty-four participants matched for age, sex, and educational background were enrolled as the sporadic ALS group (n = 22) and the control group (n = 22). All participants completed comprehensive neuropsychological tests, including the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the Stroop Color-Word Interference Test (SCWT), the Wisconsin Card Sorting Test (WCST), and the Frontal Assessment Battery. The participants underwent a series of 3.0 Tesla magnetic resonance imaging (MRI) scans. Resting-state functional MRI (Rs-fMRI) using the amplitude of low-frequency fluctuation (ALFF) was performed. Three-dimensional T1-weighted anatomical images obtained by voxel-based morphometry (VBM) were used to conduct correlation analyses and group comparisons with the demographic and neuropsychological characteristics. The results indicated that the decreased gray matter (GM) volume in the bilateral precentral gyri and increased ALFF values in the right parahippocampal gyrus, left inferior temporal gyrus, left anterior cingulate gyrus, right superior frontal gyrus, and left middle occipital gyrus were identified in the sporadic ALS group. The increased ALFF value in the right parahippocampal gyrus was positively correlated with ALS progression rate. The ALS patients exhibited poor performances on cognitive and executive tests, which were significantly or marginally significantly correlated with the ALFF values in the anterior cingulate gyrus and the frontal, temporal, and parahippocampal cortices. In conclusion, these findings provide evidence of an extramotor involvement and suggest that the ALFF value in the right parahippocampal gyrus could represent a potential marker to monitor disease progression.
Topics: Adult; Amyotrophic Lateral Sclerosis; Case-Control Studies; Executive Function; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Parahippocampal Gyrus
PubMed: 26041566
DOI: 10.1007/s12031-015-0583-9 -
Cerebral Cortex (New York, N.Y. : 1991) Mar 2004The parahippocampal gyrus, located at the medial temporal lobe, is a key structure in declarative memory processing. We have analyzed the general organization of the...
The parahippocampal gyrus, located at the medial temporal lobe, is a key structure in declarative memory processing. We have analyzed the general organization of the parahippocampal gyrus in the baboon, a nonhuman primate species relatively close to human. This region is rostrocaudally made up of the temporopolar, perirhinal, entorhinal (divided into seven subfields) and posterior parahippocampal (areas TH and TF) cortices. The basic analysis has been performed in three brains, serially sectioned and stained with thionin, myelin stain, acetylcholinesterase and parvalbumin, to determine cytoarchitectonic boundaries. Borders of all subfields were charted onto camera lucida drawings, and two-dimensional maps of the surface and topography of the parahippocampal gyrus were made. Finally, the limits of each parahippocampal area were then transposed on corresponding MR images (commonly used for in vivo PET or functional MRI activation studies) of two animals for precise identification. The general cytoarchitectonic features of the baboon parahippocampal gyrus are similar to macaques, but the size of temporopolar cortex and the laminar organization of perirhinal and posterior parahippocampal cortices resemble humans more than macaque species. In conclusion, the size and structure of the baboon parahippocampal cortex makes this species very appropriate for experimental studies on memory function.
Topics: Animals; Cerebral Cortex; Entorhinal Cortex; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Neural Pathways; Papio; Parahippocampal Gyrus; Visual Cortex
PubMed: 14754864
DOI: 10.1093/cercor/bhg123 -
Trends in Cognitive Sciences Aug 2013The parahippocampal cortex (PHC) has been associated with many cognitive processes, including visuospatial processing and episodic memory. To characterize the role of... (Review)
Review
The parahippocampal cortex (PHC) has been associated with many cognitive processes, including visuospatial processing and episodic memory. To characterize the role of PHC in cognition, a framework is required that unifies these disparate processes. An overarching account was proposed whereby the PHC is part of a network of brain regions that processes contextual associations. Contextual associations are the principal element underlying many higher-level cognitive processes, and thus are suitable for unifying the PHC literature. Recent findings are reviewed that provide support for the contextual associations account of PHC function. In addition to reconciling a vast breadth of literature, the synthesis presented expands the implications of the proposed account and gives rise to new and general questions about context and cognition.
Topics: Cognition; Humans; Parahippocampal Gyrus
PubMed: 23850264
DOI: 10.1016/j.tics.2013.06.009 -
Annals of the New York Academy of... Jun 2000The parahippocampal region, as defined in this review, comprises the cortical regions that surround the rodent hippocampus including the perirhinal, postrhinal, and... (Review)
Review
The parahippocampal region, as defined in this review, comprises the cortical regions that surround the rodent hippocampus including the perirhinal, postrhinal, and entorhinal cortices. The comparable regions in the primate brain are the perirhinal, parahippocampal, and entorhinal cortices. The perirhinal and postrhinal/parahippocampal cortices provide the major polysensory input to the hippocampus through their entorhinal connections and are the recipients of differing combinations of sensory information. The differences in the perirhinal and postrhinal cortical afferentation have important functional implications, in part, because these two regions project with different terminal patterns to the entorhinal cortex. The perirhinal cortex projects preferentially to the lateral entorhinal area (LEA), and the postrhinal cortex projects preferentially to the medial entorhinal area (MEA) and the caudal portion of LEA. Although the perirhinal and postrhinal cortices provide the major cortical input to the entorhinal cortex, the entorhinal cortex itself receives some direct cortical input. An examination of the cortical afferentation of the entorhinal cortex reveals an interesting principle of connectivity among these regions; the composition of the direct neocortical input to the LEA is more similar to that of the perirhinal cortex, and the composition of the direct neocortical input to the MEA is more similar to that of the postrhinal cortex. Thus, polymodal associational input to the LEA and the MEA exhibits some segregation and is organized in parallel. The organization of intrinsic connections for each of the parahippocampal regions also contributes to the segregation of information into parallel pathways.
Topics: Animals; Cerebral Cortex; Entorhinal Cortex; Humans; Neural Pathways; Olfactory Pathways; Parahippocampal Gyrus
PubMed: 10911865
DOI: 10.1111/j.1749-6632.2000.tb06717.x -
European Neuropsychopharmacology : the... Dec 2020The current study aimed to identify alterations in brain activation and connectivity related to memory suppression in posttraumatic stress disorder (PTSD) using the...
The current study aimed to identify alterations in brain activation and connectivity related to memory suppression in posttraumatic stress disorder (PTSD) using the Think/No-Think paradigm during functional magnetic resonance imaging (fMRI). Reduced activation in the parahippocampal cortex during No-Think vs. Baseline trials was found in participants with PTSD compared to controls with no history of trauma (pFWE<0.05). Trauma-related intrusive memories (r = 0.562, p = 0.046) and avoidance behaviors (r = 0.636, p = 0.020) were positively correlated with parahippocampal cortex activation during memory suppression in the PTSD group. Psychophysiological interactions (PPI) analysis identified increased functional connectivity between the inferior frontal gyrus and the parahippocampus during memory suppression in the PTSD group compared to trauma-free controls (pFWE<0.05). Our findings support a network-based phenotype for altered memory suppression in individuals with PTSD rooted in dysfunctional parahippocampal-prefrontal coupling. These data validate neural models of PTSD and offer a novel neural circuit for brain-based interventions targeting trauma-related memory.
Topics: Adult; Cerebral Cortex; Female; Humans; Magnetic Resonance Imaging; Male; Memory; Mental Recall; Middle Aged; Parahippocampal Gyrus; Photic Stimulation; Stress Disorders, Post-Traumatic; Young Adult
PubMed: 32967787
DOI: 10.1016/j.euroneuro.2020.09.634 -
Annals of the New York Academy of... Jun 2000The piriform and perirhinal cortices are parahippocampal structures with strong connections to limbic structures, including the amygdala and hippocampus, as well as... (Review)
Review
The piriform and perirhinal cortices are parahippocampal structures with strong connections to limbic structures, including the amygdala and hippocampus, as well as other parahippocampal structures such as the entorhinal cortex. In this paper, we present results, based on anatomical, physiological, and kindling studies, that suggest that the perirhinal and piriform cortices might be very important in the secondary generalization of limbic seizures, particularly those with convulsive expression. These kindling data further suggest that the progressive lowering of afterdischarge thresholds in the parahippocampal structures, due to insult and/or genetic predisposition, might provide the neural basis for the clinical presentation of temporal lobe epilepsy.
Topics: Animals; Differential Threshold; Entorhinal Cortex; Kindling, Neurologic; Neural Pathways; Parahippocampal Gyrus; Seizures; Status Epilepticus
PubMed: 10911884
DOI: 10.1111/j.1749-6632.2000.tb06736.x -
The American Journal of Psychiatry Apr 2006
Topics: Dissociative Disorders; Dissociative Identity Disorder; Humans; Iodobenzenes; Life Change Events; Models, Neurological; Models, Psychological; Parahippocampal Gyrus; Psychiatric Status Rating Scales; Schizophrenia; Schizophrenic Psychology; Terminology as Topic
PubMed: 16585425
DOI: 10.1176/ajp.2006.163.4.566 -
Neurobiology of Learning and Memory Nov 2021Multiple paradigms indicate that the physical environment can influence spontaneous and learned behavior. In rodents, context-dependent behavior is putatively supported... (Review)
Review
Multiple paradigms indicate that the physical environment can influence spontaneous and learned behavior. In rodents, context-dependent behavior is putatively supported by the prefrontal cortex and the medial temporal lobe. A preponderance of the literature has targeted the role of the hippocampus. In addition to the hippocampus proper, the medial temporal lobe also comprises parahippocampal areas, including the perirhinal and postrhinal cortices. These parahippocampal areas directly connect with multiple regions in the prefrontal cortex. The function of these connections, however, is not well understood. This article first reviews the involvement of the perirhinal, postrhinal, and prefrontal cortices in context-dependent behavior in rodents. Then, based on functional and anatomical evidence, we suggest that perirhinal and postrhinal contributions to context-dependent behavior go beyond supporting context representation in the hippocampus. Specifically, we propose that the perirhinal and postrhinal cortices act as a contextual-support network that directly provides contextual and spatial information to the prefrontal cortex. In turn, the perirhinal and postrhinal cortices modulate prefrontal input to the hippocampus in the service of context-guided behavior.
Topics: Animals; Hippocampus; Humans; Learning; Neural Pathways; Parahippocampal Gyrus; Prefrontal Cortex; Recognition, Psychology
PubMed: 34537379
DOI: 10.1016/j.nlm.2021.107520 -
Progress in Neuro-psychopharmacology &... Jul 2004Neuropathological abnormalities in schizophrenia have been demonstrated in the parahippocampal gyrus (PHG). Only a few studies on first-episode neuroleptic-naive... (Clinical Trial)
Clinical Trial
Neuropathological abnormalities in schizophrenia have been demonstrated in the parahippocampal gyrus (PHG). Only a few studies on first-episode neuroleptic-naive schizophrenia patients have been done using in vivo neuroimaging techniques. The authors examined the PHG morphology using structural MRI in neuroleptic-naive subjects with first episode psychoses. Volumetric measurements of PHG and intracranial volume (ICV) were obtained on subjects with schizophrenia and schizoaffective disorders (SCZ; n = 33), nonschizophrenia psychotic disorders (NSCZ; n = 11) and matched healthy subjects (HS; n = 43). The subjects were rated on the Brief Psychiatric Rating Scale (BPRS). Group differences and clinical correlations of ICV-adjusted PHG volumes were examined. Left PHG was significantly different across the groups consisting of SCZ, NSCZ and HS. PHG was larger in NSCZ compared to SCZ but not relative to HS. Bilaterally, PHG was no different between SCZ and HS. In pooled psychotic patients, the PHG volume negatively correlated with total positive symptom, delusion and conceptual disorganization scores on BPRS. Patients with delusions had relatively smaller PHG compared to nondelusional subjects. Observed differences in PHG volume in first-episode neuroleptic-naive patients suggest that these observations are not confounded by illness chronicity or medication effects. Significant association of PHG volume with psychotic symptoms suggests that PHG pathology plays an important role in the etiopathology of psychosis and its symptoms.
Topics: Adult; Delusions; Female; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Parahippocampal Gyrus; Psychiatric Status Rating Scales; Psychotic Disorders; Schizophrenia
PubMed: 15276690
DOI: 10.1016/j.pnpbp.2004.01.017