Temporal Lobe Volume Research Articles

Relationship of temporal lobe volumes to neuropsychological test performance in healthy children

Ecological validity of neuropsychological assessment includes the ability of tests to predict real-world functioning and/or covary with brain structures. Studies have examined the relationship between adaptive skills and test performance, with less focus on the association between regional brain volumes and neurobehavioral function in healthy children. The present study examined the relationship between temporal lobe gray matter volumes and performance on two neuropsychological tests hypothesized to measure temporal lobe functioning (visual perception—VP; peabody picture vocabulary test, third edition—PPVT-III) in 48 healthy children ages 5–18 years. After controlling for age and gender, left and right temporal and left occipital volumes were significant predictors of VP. Left and right frontal and temporal volumes were significant predictors of PPVT-III. Temporal volume emerged as the strongest lobar correlate with both tests. These results provide convergent and discriminant validity supporting VP as a measure of the “what” system; but suggest the PPVT-III as a complex measure of receptive vocabulary, potentially involving executive function demands.

Medial temporal lobe atrophy in vascular dementia: Visual temporal lobe rating scale

Medial temporal lobe atrophy (MTA) as assessed by magnetic resonance imaging (MRI) can be measured in several ways. First of all, visual rating scale is a quick and easy measurement. MTA is a sensitive marker for Alzheimer's disease (AD), but not specific. It has been documented in other dementias including vascular dementia (VD). This study is to evaluate the degree of MTA in VD patients using a standardized visual rating scale and to suggest the importance of the possible role of MTA in VD. Twenty-five VD, 33 AD and 27 non-demented patients underwent a coronal three-dimensional magnetization prepared rapid gradient echo brain MRI sequence. MTA was rated visually using a 5-point rating scale from 0 (no atrophy) to 4 (severe atrophy). The mean summed MTA score was 5.39 in AD, 2.16 in VD and 0.56 in non-demented patients. Most of the VD patients (80%) showed MTA. They were greater in bilateral sides compared with the non-demented group, but milder than in AD. Additionally, MTA of left side score was significantly associated with age. Medial temporal lobe volumes measured visually are smaller in size in patients with VD, although not to the same extent as in AD. This suggests that MTA in VD patients may be associated with pre-existing AD.

Predictors of outcome after temporal lobectomy for refractory temporal lobe epilepsy

To identify predictors of outcome after epilepsy surgery in patients with temporal lobe epilepsy (TLE). Seventy-six patients with normal magnetic resonance imaging (MRI) or hippocampal sclerosis on MRI who underwent anterior temporal lobe resections were included. Outcome 2 years after surgery was classified as good (Engel I and II) or poor (Engel III and IV). Gender, age at onset and duration of epilepsy, history of febrile convulsions, auras, right- or left-sided TLE, memory ipsilateral to seizure onset (Wada test), hippocampal asymmetry (HA) and T2 relaxation time, amygdala, temporal lobe and hemispheral volume were tested for associations with outcome. Sixty-seven percent had a good outcome. Of all parameters tested, only a history of febrile convulsions and HA on quantitative MRI were significantly associated with a good seizure outcome. The absence of these parameters did not exclude a good outcome, but only five of 18 patients (28%) without HA and without a history of febrile convulsions had a good outcome. Febrile convulsions and HA were predictors of outcome after epilepsy surgery in TLE. Subtle volume loss in amygdala, temporal lobe or hemispheres and the memory ipsilateral to the side of resection were not associated with outcome.

Neuropsychological function–brain structure relationships and stage of illness: An investigation into chronic and first-episode schizophrenia

Neuropsychological function–brain structure relationships may differ as a function of illness stage because of progressive brain matter loss through the course of schizophrenia. In this study, we tested whether neuropsychological function–brain structure relationships differed as a function of illness stage. In addition, we tested whether these relationships differed between older and young healthy controls. Function–structure relationships were examined in 35 first-episode patients (31 with schizophrenia, 4 with schizoaffective disorder), 54 chronic schizophrenia patients, 21 older healthy controls and 20 young healthy controls. MRI volumes of frontal and temporal lobe structures, as well as the whole brain, were estimated using a region-of-interest approach. Hierarchical multiple regression analyses were performed between the MRI and neuropsychological measures. Stronger relationships of immediate memory-total prefrontal cortex (PFC) volume in chronic than first-episode patients, and in older than young controls were observed. The abstract reasoning (WCST perseverative errors)-total temporal lobe volume relationship was stronger in older than young controls. These function–structure relationships appeared unexplained by whole brain volume or age in chronic patients. A similar dissociation between young and older subjects of both healthy and patient groups suggests that a ‘bigger-is-better’ relationship style is present in older individuals regardless of a diagnosis of schizophrenia.

Temporal lobe abnormalities and reduced hemispheric lateralization in schizophrenia patients and unaffected relatives

Event Abstract Back to Event Temporal lobe abnormalities and reduced hemispheric lateralization in schizophrenia patients and unaffected relatives Viola Oertel1, 2*, C. Knöchel1, A. Rotarska-Jagiel1, 2, 3, R. Schönmeyer1, M. Lindner1, 2, V. Van De Ven4, C. Haenschel1, 5, P. Uhlhaas1, 5, K. Maurer1 and D.E.J Linden1, 6 1 Goethe University, Germany 2 Goethe University, Germany 3 University of Cologne, Germany 4 University of Maastricht, Netherlands 5 Max-Planck-Institute for Brain Research, Germany 6 University of Wales, United Kingdom Several studies have shown a different activation pattern during the presentation of auditory stimuli of schizophrenia patients and healthy control subjects. However, none of the previous experiments examined first-degree relatives, and thus a possible genetic contribution to abnormal auditory and language processing is not clear. The aim of this study was to identify functional and anatomical correlates of dysfunctional auditory processing in patients with schizophrenia. In addition we included a gray matter volume analysis of the planum temporale. The present study included three age-matched subject groups: 15 SZ patients, 11 first-degree relatives and 15 healthy controls. High-resolution 3D-anatomical 3T-MRI and functional MRI with auditory stimulation were performed. The auditory stimulation consisted of 13 non-prosodic text fragments presented for 15, 20 or 30 seconds, alternating with a rest-condition (inter-stimulus-interval: 15 s). The subjects had to listen passively to the texts and press a button at the onset and offset of the stimulation. Cortical activation to auditory stimuli was lower for patients than controls and intermediate for relatives. In addition, patients showed a lower lateralisation of language areas towards the left hemisphere compared to the control group. This decrease of lateralisation correlated with the severity of symptoms. Patients with more severe positive symptoms, measured with the PANSS (Kay et al., 1987), also showed lower lateralization. Relatives again had intermediate values between patients and controls. The gray matter volume analysis mirrored the results from functional imaging, with a pronounced loss of temporal lobe volume in patients, and less severe reductions in relatives. Temporal lobe abnormalities (volume loss, reduced functional activation and lateralisation) were not confined to patients with schizophrenia but present, albeit to a lesser degree, in unaffected relatives. This suggests that this may represent a biological genetic marker of schizophrenia. The extent of temporal lobe abnormalities correlated with the severity of symptoms in patients. Loss of normal hemispheric asymmetry may thus be a factor in the development of schizophrenia and a key determinant of disease severity. Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Türkiye, 1 Sep - 5 Sep, 2008. Presentation Type: Poster Presentation Topic: Cerebral Asymmetry Citation: Oertel V, Knöchel C, Rotarska-Jagiel A, Schönmeyer R, Lindner M, Van De Ven V, Haenschel C, Uhlhaas P, Maurer K and Linden D (2008). Temporal lobe abnormalities and reduced hemispheric lateralization in schizophrenia patients and unaffected relatives. Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.147 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Dec 2008; Published Online: 05 Dec 2008. * Correspondence: Viola Oertel, Goethe University, Frankfurt/Main, Germany, Viola.Oertel@kgu.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Viola Oertel C. Knöchel A. Rotarska-Jagiel R. Schönmeyer M. Lindner V. Van De Ven C. Haenschel P. Uhlhaas K. Maurer D.E.J Linden Google Viola Oertel C. Knöchel A. Rotarska-Jagiel R. Schönmeyer M. Lindner V. Van De Ven C. Haenschel P. Uhlhaas K. Maurer D.E.J Linden Google Scholar Viola Oertel C. Knöchel A. Rotarska-Jagiel R. Schönmeyer M. Lindner V. Van De Ven C. Haenschel P. Uhlhaas K. Maurer D.E.J Linden PubMed Viola Oertel C. Knöchel A. Rotarska-Jagiel R. Schönmeyer M. Lindner V. Van De Ven C. Haenschel P. Uhlhaas K. Maurer D.E.J Linden Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Investigating the neuropsychological and neuroanatomical changes that occur over the first 2–3 years of illness in patients with first-episode schizophrenia

Objective This study explored the concurrent courses of the neuroanatomical and neuropsychological changes that occurred over the first 2–3 years of illness in patients with first-episode schizophrenia (FES). Methods Fifty-two patients with FES underwent neuropsychological testing and a structural magnetic resonance imaging (sMRI) scan within three months of their first presentation to mental health services with psychotic symptoms (time1). Patients' cognitive performance was evaluated via an extensive neuropsychological test battery, which assessed 9 cognitive domains. Of the 52 patients at time1, 32 returned 2–3 years later (time2) for follow-up neuropsychological testing, and 20 of these also underwent follow-up sMRI. MR images were preprocessed in SPM99. Grey matter volumes of patients' whole-brain, frontal lobes and temporal lobes were calculated by convolving the preprocessed images with manually-drawn binary masks. Results Patients exhibited longitudinal improvements in full-scale IQ, performance IQ and visual memory. In contrast, concurrent reductions in grey matter were observed for the whole-brain (3% reduction) and the frontal lobe (3.65% reduction). Furthermore, the extent of patients' whole-brain and frontal-lobe grey matter changes were positively correlated with longitudinal changes in verbal learning and memory. Discussion The results of this study suggest that while the early stages of schizophrenia are associated with a mild improvement in patients' overall cognitive functioning, they are also associated with progressive grey matter atrophy.

Diminished plasma oxytocin in schizophrenic patients with neuroendocrine dysfunction and emotional deficits

Polydipsic hyponatremic schizophrenic patients (PHS) exhibit enhanced plasma arginine vasopressin (pAVP) and hypothalamic pituitary adrenal (HPA) axis responses to stress that appear attributable to anterior hippocampal dysfunction. Neuroanatomic and electrophysiologic studies indicate oxytocin activity in PHS patients should also be affected. Furthermore, oxytocin normally diminishes HPA responses to stress and facilitates cognitive and behavioral functions impaired in schizophrenia, suggesting that diminished oxytocin activity could contribute to this subsets' neuropsychiatric disorder. In the present study, we measured plasma oxytocin levels at intervals before and after stress induction in six polydipsic hyponatremic (PHS), four polydipsic normonatremic (PNS), five nonpolydipsic normonatremic schizophrenic (NNS) patients and seven healthy controls. Most of these subjects also completed studies measuring their medial temporal lobe volumes, their hippocampal-mediated HPA feedback and their ability to discriminate different facial emotions (an oxytocin-sensitive measure which is markedly impaired in schizophrenia). Results demonstrated that 1) plasma oxytocin levels were lower ( p = .006) in hyponatremic patients relative to the other three groups, whose levels were similar and did not change. Oxytocin levels across all subjects were 2) inversely correlated with anterior hippocampal ( p = .004) (but not posterior hippocampal or amygdala volumes), and 3) directly correlated with the integrity of hippocampal-mediated HPA feedback ( p = .039). Finally, 4) oxytocin levels predicted schizophrenic patients' ability to correctly identify facial emotions ( p = .004). These preliminary data provide further evidence that neuroendocrine dysfunction in PHS reflects anterior hippocampal pathology and contributes to a characteristic neuropsychiatric syndrome.

Brain Aberrations Provide Clues to Origins of Violent Behavior

Back to table of contents Previous article Next article Clinical & Research NewsFull AccessBrain Aberrations Provide Clues to Origins of Violent BehaviorJoan Arehart-TreichelJoan Arehart-TreichelSearch for more papers by this authorPublished Online:5 Oct 2007https://doi.org/10.1176/pn.42.19.0021aWhere in the depths of the human brain does violent behavior have its inception? Scientists are not sure, but reduced prefrontal gray matter and decreases in total brain volume and temporal-lobe volume have been linked with violent behavior in some people with antisocial personality disorder. In addition, poor orbitofrontal functioning, an abnormally large putamen, and abnormally small amygdalae and hippocampi have been linked with violent behavior in some schizophrenia patients.And now aberrations in cortical thickness have been linked with violent behavior in both types of subjects. The findings come from Arthur Toga, Ph.D., director of the Laboratory of Neuro Imaging at the University of California at Los Angeles, and his coworkers. Their findings were published in the September American Journal of Psychiatry.Toga and his coworkers used magnetic resonance imaging to compare regional differences in cortical thickness in four groups of subjects—14 individuals with antisocial personality disorder and a history of violence, 12 individuals with schizophrenia and a history of violence, 15 individuals with schizophrenia but no history of violence, and 15 healthy nonviolent comparison subjects. All 56 subjects were right-handed and closely matched on demographic variables.The scientists found that cortical thinning in the medial prefrontal cortex differentiated the violent antisocial group from the other three groups and that cortical thinning in the sensory motor cortex differentiated the violent antisocial group and the violent schizophrenia group from the two nonviolent subject groups.Moreover, the findings add to the evidence that while violent subjects with antisocial personalities and violent subjects with schizophrenia share some common structural brain abnormalities, differences do exist.How might a thinning of the prefrontal cortex set the stage for violence? It might impair judgment, emotion, self-monitoring, and impulsivity, the scientists proposed in their study report. And how might a thinning of the sensory motor cortex prep the brain for violence? By compromising movement in some way, the scientists speculated. That is, while they found no differences in motor speed between the violent groups and the nonviolent ones, they did find deficits in eye-hand coordination in the former.The study was funded by the National Institutes of Health and the Stanley Medical Research Institute in the United States, and the Zito Trust, Community Fund, and Wellcome Trust in the United Kingdom.“Regional Cortical Thinning in Subjects With Violent Antisocial Personality Disorder or Schizophrenia” is posted at<http://ajp.psychiatryonline.org/cgi/content/full/164/9/1418>.▪ ISSUES NewArchived

Interobserver and within-subject variances of T 2-relaxation time and 1H-metabolite ratios in the normal hippocampus

Purpose To investigate the magnetic resonance (MR) reproducibility of normal hippocampal volume (HV), temporal lobe volume (TLV), transversal relaxation time (T 2) and 1H-MR spectroscopy ( 1H-MRS) metabolite ratios. Materials and methods Two sets of HV, TLV, T 2 and MR spectroscopic metabolite signal ratios were determined in 27 healthy volunteers. HV and TLV were measured with a T 1-weighted MR sequence; whereas T 2 measurements were performed with conventional spin-echo (CSE) and fast spin-echo (FSE) MR imaging sequences. The interobserver and within-subject variances of T 2 measurements were estimated. Results Estimated right and left HV coefficients of variation (CV) = 0.13. FSE T 2 measurements showed no significant differences in the interobserver (CV = 0.02) and within-subject variances (CV = 0.02). Measurements showed no differences in the interobserver (CV = 0.02) and within-subject (CV = 0.04) variances for the CSE T 2 of the right and left hippocampi. Metabolite ratios between N-acetyl aspartate (NAA) and creatine (Cr), choline (Cho) and creatine, and NAA and choline plus creatine (Cho + Cr) for the right hippocampus were 2.29 ± 0.19, 1.52 ± 0.14 and 0.91 ± 0.05, respectively. Metabolite ratios for the left hippocampus were 2.18 ± 0.10, 1.48 ± 0.10 and 0.88 ± 0.06, respectively. Conclusions HV, TLV, T 2 and 1H MRS metabolite ratio measurements showed fair reproducibility with small CVs, and no differences in the interobserver and within-subject variances, including no differences between right and left TLV, and in the right and left T 2.

Autopsy-confirmed Alzheimer's disease versus clinically diagnosed Alzheimer's disease in the Cache County Study on Memory and Aging: A comparison of quantitative MRI and neuropsychological findings

Atrophy of specific, regional, and generalized brain structures occurs as a result of the Alzheimer's disease (AD) process. Comparing AD patients with histopathological confirmation of the disease at autopsy to those without autopsy but who were clinically diagnosed using the same antemortem criteria will provide further evidence of the utility and accuracy of neuropsychological assessments at the time of diagnosis, as well as the efficacy of quantitative magnetic resonance imaging (qMRI) in demonstrating gross neuropathological changes associated with the disease. The Cache County Study of Aging provides a unique opportunity to determine how closely AD subjects with only the clinical diagnosis match similarly diagnosed AD subjects but with postmortem confirmation of the disease. qMRI volumes of various brain structures, as well as neuropsychological outcome measures from an expanded battery, were obtained in 31 autopsy-confirmed AD subjects and 45 clinically diagnosed AD subjects. Of the various qMRI variables examined, only total temporal lobe volume was different, where those with postmortem confirmation had reduced volume. No significant differences between the two groups were found with any of the neuropsychological outcome measures. These findings confirm the similarity in neuroimaging and neuropsychological assessment findings between those with just the clinical diagnosis of AD and those with an autopsy-confirmed diagnosis in the moderate-to-severe stage of the disease at the time of diagnosis.

The COMT Val158Met polymorphism and temporal lobe morphometry in healthy adults

We examined the relationship between COMT Val158Met genotype and temporal lobe volumes, including the caudate as a control region. Thirty-one healthy subjects completed 1.5T brain MRI and genotyping. After controlling for demographics, Val158 allele homozygotes exhibited significantly smaller temporal lobe and hippocampal volumes, with a trend for smaller amygdala volumes.

Patterns of Structural MRI Abnormalities in Deficit and Nondeficit Schizophrenia

Negative symptoms of schizophrenia have generally been found in association with ventricular enlargement and prefrontal abnormalities. These relationships, however, have not been observed consistently, most probably because negative symptoms are heterogeneous and result from different pathophysiological mechanisms. The concept of deficit schizophrenia (DS) was introduced by Carpenter et al to identify a clinically homogeneous subgroup of patients characterized by the presence of primary and enduring negative symptoms. Findings of brain structural abnormalities reported by magnetic resonance imaging (MRI) studies focusing on DS have been mixed. The present study included 34 patients with DS, 32 with nondeficit schizophrenia (NDS), and 31 healthy comparison subjects, providing the largest set of MRI findings in DS published so far. The Schedule for the Deficit Syndrome was used to categorize patients as DS or NDS patients. The 2 patient groups were matched on age and gender and did not differ on clinical variables, except for higher scores on the negative dimension and more impaired interpersonal relationships in DS than in NDS subjects. Lateral ventricles were larger in NDS than in control subjects but were not enlarged in patients with DS. The cingulate gyri volume was smaller in NDS but not in DS patients as compared with healthy subjects. Both groups had smaller dorsolateral prefrontal cortex and temporal lobes than healthy subjects, but DS patients had significantly less right temporal lobe volume as compared with NDS patients. These findings do not support the hypothesis that DS is the extreme end of a severity continuum within schizophrenia.

Persistent seizures following left temporal lobe surgery are associated with posterior and bilateral structural and functional brain abnormalities

To perform a quantitative MRI and retrospective electrophysiological study to investigate whether persistent post-surgical seizures may be due to brain structural and functional abnormalities in temporal lobe cortex beyond the margins of resection and/or bilateral abnormalities in patients with temporal lobe epilepsy (TLE). In 22 patients with left TLE and histopathological evidence of hippocampal sclerosis, we compared pre-surgical brain morphology between patients surgically remedied (Engel's I) and patients with persistent post-surgical seizures (PPS, Engel's II-IV) using voxel-based morphometry (VBM). Routine pre-surgical EEG and invasive and non-invasive telemetry investigations were additionally compared between patient groups. Results indicated widespread structural and functional abnormalities in patients with PPS relative to surgically remedied patients. In particular, patients with PPS had significantly reduced volume of the ipsilateral posterior medial temporal lobe and contralateral medial temporal lobe relative to surgically remedied patients. Furthermore, successful surgery was associated with clear anterior (89%) and unilateral (100%) temporal lobe EEG abnormalities, whilst PPS were associated with widespread ipsilateral (91%) and bilateral (82%) temporal lobe abnormalities. We suggest that these preliminary data support the hypothesis that PPS after temporal lobe surgery are due to functionally connected epileptogenic cortex remaining in the ipsilateral posterior temporal lobe and/or in temporal lobe contralateral to resection.

Frontal and temporal volumes in children with epilepsy

This study examined if children with cryptogenic epilepsy and complex partial seizures (CPS) have smaller total brain, frontal, and temporal lobe volumes than normal children and how this is related to seizure, cognitive, psychiatric, and demographic variables. Forty-four children with CPS and 38 normal children, aged 5–16 years, underwent brain MRI scans at 1.5 T. Tissue was segmented, and total brain, frontal lobe, frontal parcellation, and temporal lobe volumes were computed. Other than significantly larger temporal lobe white matter volumes in the CPS group, there were no significant differences in brain volumes between the CPS and normal groups. Earlier onset, longer duration of illness, younger chronological age, and presence of a psychiatric diagnosis were significantly related to smaller frontotemporal volumes in subjects with CPS. Although these findings suggest that CPS might affect development of the temporal and frontal regions, we are unable to rule out the possibility that smaller frontotemporal volumes might predispose children to CPS. These findings highlight the need to control for seizure, cognitive, psychiatric, and demographic variables in studies of frontotemporal volumes in pediatric CPS.

Olfactory Functioning in Schizophrenia: Relationship to Clinical, Neuropsychological, and Volumetric MRI Measures

Deficits in odor identification and detection threshold sensitivity have been observed in schizophrenia but their relationship to clinical, cognitive, and biologic measures have not been clearly established. Our objectives were to examine the relationship between measures of odor identification and detection threshold sensitivity and clinical, neuropsychological, and anatomic brain measures. Twenty-one patients with schizophrenia and 20 healthy controls were administered psychophysical tests of odor identification and detection threshold sensitivity to phenyl ethyl alcohol. In addition, clinical symptom ratings, neuropsychological measures of frontal and temporal lobe function and whole brain MRIs were concurrently obtained. Patients exhibited significant deficits in odor identification but normal detection threshold sensitivity. Poorer odor identification scores were associated with longer duration of illness, increased negative and disorganized symptoms, and the deficit syndrome, as well as impairments in verbal and nonverbal memory. Better odor detection thresholds were specifically associated with first-rank or productive symptoms. Larger left temporal lobe volumes with MRI were associated with better odor identification in controls but not in patients. Given the relevance of the neural substrate, and the evidence of performance deficits, psychophysical probes of the integrity of the olfactory system hold special promise for illuminating aspects of the neurobiology underlying schizophrenia.

Radiosurgery of functioning pituitary adenomas: Comparison of different treatment techniques including dynamic and conformal arcs, shaped beams, and IMRT

Purpose: Evaluation of different techniques including intensity-modulated radiotherapy (IMRT) for stereotactic radiosurgery (SRS) of pituitary adenoma (PA). Methods and Materials: Between January 2003 and February 2005, 152 SRS procedures were performed. Ten patients with PA were compared: conformal vs. dynamic arc treatment with micromultileaf collimator (mMLC) vs. circular collimators vs. 8–10 conformal static mMLC beams with and without IMRT. Prescribed total dose: 18 Gy (90%). Constraints: D max optic chiasm 10Gy temporal lobe 10Gy temporal lobe. Results: For the end point "improvement in coverage," an advantage with IMRT was noted for 5 of 10 patients as compared with the dynamic arc approach. Volume treated >18 Gy outside the planning target volume was lowest in 9 of 10 patients after IMRT; 1 patient achieved better conformity with circular collimators. As for Vol 10Gy temporal lobe, an advantage was depicted for 1 of 10 patients with IMRT, the other techniques appearing equally effective in shielding the temporal lobe. With all techniques Vol 10 Gy temporal lobe was max optic chiasm Conclusions: Novalis-based radiosurgery using dynamic arc treatment with mMLC is considered a safe and appropriate approach for SRS of PA.

Neurobiology of Schizophrenia

With its hallucinations, delusions, thought disorder, and cognitive deficits, schizophrenia affects the most basic human processes of perception, emotion, and judgment. Evidence increasingly suggests that schizophrenia is a subtle disorder of brain development and plasticity. Genetic studies are beginning to identify proteins of candidate genetic risk factors for schizophrenia, including dysbindin, neuregulin 1, DAOA, COMT, and DISC1, and neurobiological studies of the normal and variant forms of these genes are now well justified. We suggest that DISC1 may offer especially valuable insights. Mechanistic studies of the properties of these candidate genes and their protein products should clarify the molecular, cellular, and systems-level pathogenesis of schizophrenia. This can help redefine the schizophrenia phenotype and shed light on the relationship between schizophrenia and other major psychiatric disorders. Understanding these basic pathologic processes may yield novel targets for the development of more effective treatments.

P1-244: Brain reserve: The impact of complex mental activity on dementia incidence, cognitive decline and hippocampal structure and function

Brain reserve is the phenomenon by which complex mental activity alters an individual's risk for developing dementia. To review the epidemiological literature with respect to brain reserve effects on dementia incidence and cognitive decline. New data related to brain reserve effects on medial temporal lobe volume will also be presented. Quantitative parametric meta–analysis of cognitive dementia studies and non–parametric analysis of cognitive decline studies. Longitudinal study of cognition and MRI volumetry. Meta–analysis revealed a significant reduction in risk for dementia incidence based on history of high complex mental activity (OR 0.54, CI:0.49–0.59) and a robust association with attenuated cognitive decline. Our own longitudinal study found that a history of complex mental activity was correlated with less hippocampal atrophy after control for intracranial volume (r=0.26, p=0.046). There is compelling epidemiological evidence that complex mental activity across the lifespan is associated with a lower risk for dementia and cognitive decline. We have found that part of this association may be mediated by differential medial temporal lobe atrophy.

Magnetic resonance imaging abnormalities in young euthymic patients with bipolar affective disorder

Temporal lobe and limbic structures may be abnormal in bipolar disorder. T2-weighted magnetic resonance imaging (MRI) scans frequently show deep white matter lesions. MRI was performed on 50 young (19-39 years) euthymic patients with bipolar disorder and 26 controls. Mean temporal lobe volumes were reduced in patients (right, 9.42 cm3; left, 6.33 cm3) but this could not but this could not be ascribed to a specific structure. Deep white matter lesions were present in 5 patients but no controls raising questions of their aetiological significance.

O3-04-05: Association between memory complaints and reduced temporal lobe volume in middle-aged adults: A voxel-based morphometry study

O3-04-05: Association between memory complaints and reduced temporal lobe volume in middle-aged adults: A voxel-based morphometry study