Frontal Lobe Asymmetry Research Articles

Loss of normal facial asymmetry in schizophrenia and bipolar disorder: Implications for development of brain asymmetry in psychotic illness

Development of the craniofacies occurs in embryological intimacy with development of the brain and both show normal left-right asymmetries. While facial dysmorphology occurs to excess in psychotic illness, facial asymmetry has yet to be investigated as a putative index of brain asymmetry. Ninety-three subjects (49 controls, 22 schizophrenia, 22 bipolar disorder) received 3D laser surface imaging of the face. On geometric morphometric analysis with (x, y, z) visualisations of statistical models for facial asymmetries, in controls the upper face and periorbital region, which share embryological intimacy with the forebrain, showed marked asymmetries. Their geometry included: along the x-axis, rightward asymmetry in its dorsal-medial aspects and leftward asymmetry in its ventral-lateral aspects; along the z-axis, anterior protrusion in its right ventral-lateral aspect. In both schizophrenia and bipolar disorder these normal facial asymmetries were diminished, with residual retention of asymmetries in bipolar disorder. This geometry of normal facial asymmetries shows commonalities with that of normal frontal lobe asymmetries. These findings indicate a trans-diagnostic process that involves loss of facial asymmetries in both schizophrenia and bipolar disorder. Embryologically, they implicate loss of face-brain asymmetries across gestational weeks 7–14 in processes that involve genes previously associated with risk for schizophrenia.

Examining Frontal Lobe Asymmetry and Its Potential Role in Aggressive Behaviors in Early Alzheimer's Disease.

Neuropsychiatric symptoms (NPS) in patients with dementia lead to caregiver burdens and worsen the patient's prognosis. Although many neuroimaging studies have been conducted, the etiology of NPS remains complex. We hypothesize that brain structural asymmetry could play a role in the appearance of NPS. This study explores the relationship between NPS and brain asymmetry in patients with Alzheimer's disease (AD). Demographic and MRI data for 121 mild AD cases were extracted from a multicenter Japanese database. Brain asymmetry was assessed by comparing the volumes of gray matter in the left and right brain regions. NPS was evaluated using the Neuropsychiatric Inventory (NPI). Subsequently, a comprehensive assessment of the correlation between brain asymmetry and NPS was conducted. Among each NPS, aggressive NPS showed a significant correlation with asymmetry in the frontal lobe, indicative of right-side atrophy (r = 0.235, p = 0.009). This correlation remained statistically significant even after adjustments for multiple comparisons (p < 0.01). Post-hoc analysis further confirmed this association (p < 0.05). In contrast, no significant correlations were found for other NPS subtypes, including affective and apathetic symptoms. The study suggests frontal lobe asymmetry, particularly relative atrophy in the right hemisphere, may be linked to aggressive behaviors in early AD. These findings shed light on the neurobiological underpinnings of NPS, contributing to the development of potential interventions.

Effects of outdoor activity intensities on college students’ indoor thermal perception and cognitive performance

Using neurobehavioral tests, electroencephalogram signal monitoring, and questionnaire surveys, we recruited 158 healthy college students to explore the effects of light, moderate, and vigorous intensity activities on indoor thermal perception, cognitive performance, physical health and emotions in a hot outdoor environment. Our results suggested four principal outcomes: (1) compared with the pre-exercise, reduction in mean thermal sensation gradually increased while reduction in mean thermal comfort decreased as the proportion of thermal symptoms increased by 17.0%, 48.0%, and 76.0% during light to vigorous activity; (2) when the Universal Thermal Climate Index changed between 23.0 °C and 49.2 °C, moderate intensity activity can maximize the cognitive performance of college students indoors; (3) the skin temperature measured at the upper arm increased at higher intensity activity. Systolic pressure, diastolic pressure, and eardrum temperature significantly increased after engaging in different intensity activities. Heart rate showed a significant increase after moderate to vigorous intensity, while oxyhemoglobin saturation decreased following vigorous intensity; and (4) when returning indoors after engaging in outdoor activities, frontal brain asymmetry increased by 0.17 as positive emotions enhanced; but after vigorous intensity, the frontal lobe asymmetry decreased by 0.11 as negative emotions increased. Our results could provide fundamental guidance to improve the indoor learning efficiency and thermal comfort of college students.

Network analysis of frontal lobe alpha asymmetry confirms the neurophysiological basis of four subtypes of depressive behavior.

Although depression is widespread carries a major disease burden, current treatments remain non-universally effective, arguably due to the heterogeneity of depression, and leading to the consideration of depressive "subtypes" or "depressive behavior subtypes." One such model of depressive behavior (DB) subtypes was investigated for its associations with frontal lobe asymmetry (FLA), using a different data analytic procedure than in previous research in this field. 100 community volunteers (54 males, 46 females) aged between 18 yr. and 75 years (M = 32.53 yr., SD = 14.13 yr) completed the Zung Self-rating Depression Scale (SDS) and underwent 15 min of eyes closed EEG resting data collection across 10 frontal lobe sites. DB subtypes were defined on the basis of previous research using the SDS, and alpha-wave (8-13 Hz) data produced an index of FLA. Data were examined via network analysis. Several network analyses were conducted, producing two models of the association between DB subtypes and FLA, confirming unique neurophysiological profiles for each of the four DB subtypes. As well as providing a firm basis for using these DB subtypes in clinical settings, these findings provide a reasonable explanation for the inconsistency in previous FLA-depression research.

EEG frontal lobe asymmetry as a function of sex, depression severity, and depression subtype

To investigate possible contributors to the inconsistent association between frontal lobe asymmetry (FLA) and depression, EEG data were collected across five frontal sites, and examined for their associations with four subtypes of depression (Depressed mood, Anhedonia, Cognitive depression, Somatic depression). One hundred community volunteers (54 males, 46 females) aged at least 18 yr completed standardized scales for depression and anxiety, and gave EEG data under Eyes Open and Eyes Closed conditions. Results indicated that, although there was no significant correlation between the differences in EEG power across each of the five pairs of frontal sites and total depression scores, there were several meaningful correlations (accounting for at least 10% of the variance) between specific EEG site differences data and each of the four depression subtypes. There were also different patterns of association between FLA and the depression subtypes according to sex, and total depression severity. These findings help to explain the apparent inconsistency in previous FLA-depression results, and argue for a more nuanced approach to this hypothesis.

Asymmetry of the midfacial skeleton of eastern lowland gorillas (Gorilla beringei graueri) and potential association with frontal lobe asymmetries

In 1973, Groves and Humphrey reported facial asymmetry in eastern gorillas and suggested that it may be indicative of asymmetrical brain function. Being cautious, the authors favored the explanation that facial asymmetry was likely due to asymmetrical chewing behavior rather than anatomical asymmetry of the cerebral hemispheres. The nature of the association between lateralized functions (e.g., handedness, mastication) and brain asymmetries in hominoids represents an active field of research. There has been both support (Hoogmartens and Caubergh, 1987; Nisan et al., 2004) and lack of support (Martinez-Gomis et al., 2009) for an association between chewing side preference and handedness in humans. In gorillas, contradictory results can be found on the question of handedness, varying from no handedness (Harrison and Nystrom, 2010) to equal proportion of right and left (Fagot and Vauclair, 1988; Byrne and Byrne, 1991; Parnell, 2001; Lambert, 2012) to true handedness (Meguerditchian et al., 2010). Cerebral anatomical asymmetries, and particularly fronto-occipital petalia, have been found to be related to handedness in modern humans (LeMay, 1976, 1977; Galaburda et al., 1978; LeMay and Kido, 1978; LeMay et al., 1982; Kertesz et al., 1986, 1990; but see Chiu and Damasio, 1980), and more generally to specific aspects of human cognition (Hecaen and Albert, 1978; Nass and Gazzaniga, 1987; Bryden, 1988; Gazzaniga, 1995a, b; Harrington, 1995). The existence of asymmetrical patterns for the frontal and occipital petalias in great apes, including Gorilla beringei graueri, have recently been reported (Balzeau and Gilissen, 2010; Balzeau et al., 2012). However, the potential association between facial and cerebral anatomical asymmetries in great apes and its functional and evolutionary implications remain unclear. Moreover, the original paper of Groves and Humphrey (1973) has been over-interpreted, as several authors refer to it as a claim of cerebellar asymmetry in gorillas (e.g., Balonov et al., 1984; Hopkins and Marino, 2000; Holloway et al., 2004). Here, we propose to quantify facial asymmetry in adult eastern lowland gorillas (Gorilla beringei graueri), determine whether or not directional asymmetry (DA) is present in our sample, and subsequently investigate the potential relationship between facial and frontal lobe asymmetries using data previously published by Balzeau and Gilissen (2010).

Frontal asymmetry in behavioral variant frontotemporal dementia: clinicoimaging and pathogenetic correlates

We aimed to assess associations between clinical, imaging, pathologic, and genetic features and frontal lobe asymmetry in behavioral variant frontotemporal dementia (bvFTD). Volumes of the left and right dorsolateral, medial, and orbital frontal lobes were measured in 80 bvFTD subjects and subjects were classified into 3 groups according to the degree of asymmetry (asymmetric left, asymmetric right, symmetric) using cluster analysis. The majority of subjects were symmetric (65%), with 20% asymmetric left and 15% asymmetric right. There were no clinical differences across groups, although there was a trend for greater behavioral dyscontrol in right asymmetric compared with left asymmetric subjects. More widespread atrophy involving the parietal lobe was observed in the symmetric group. Genetic features differed across groups with symmetric frontal lobes associated with C9ORF72 and tau mutations, while asymmetric frontal lobes were associated with progranulin mutations. These findings therefore suggest that neuroanatomical patterns of frontal lobe atrophy in bvFTD are influenced by specific gene mutations.

Automatic analysis of cerebral asymmetry: an exploratory study of the relationship between brain torque and planum temporale asymmetry

Leftward occipital and rightward frontal lobe asymmetry (brain torque) and leftward planum temporale asymmetry have been consistently reported in postmortem and in vivo neuroimaging studies of the human brain. Here automatic image analysis techniques are applied to quantify global and local asymmetries, and investigate the relationship between brain torque and planum temporale asymmetries on T1-weighted magnetic resonance (MR) images of 30 right-handed young healthy subjects (15 male, 15 female). Previously described automatic cerebral hemisphere extraction and 3D interhemispheric reflection-based methods for studying brain asymmetry are applied with a new technique, LowD (Low Dimension), which enables automatic quantification of brain torque. LowD integrates extracted left and right cerebral hemispheres in columns orthogonal to the midsagittal plane (2D column maps), and subsequently integrates slices along the brain's anterior–posterior axis (1D slice profiles). A torque index defined as the magnitude of occipital and frontal lobe asymmetry is computed allowing exploratory investigation of relationships between this global asymmetry and local asymmetries found in the planum temporale. LowD detected significant torque in the 30 subjects with occipital and frontal components found to be highly correlated ( P < 0.02). Significant leftward planum temporale asymmetry was detected ( P < 0.05), and the torque index correlated with planum temporale asymmetry ( P < 0.001). However, torque and total brain volume were not correlated. Therefore, although components of cerebral asymmetry may be related, their magnitude is not influenced by total hemisphere volume. LowD provides increased sensitivity for detection and quantification of brain torque on an individual subject basis, and future studies will apply these techniques to investigate the relationship between cerebral asymmetry and functional laterality.

Attenuation of frontal asymmetry in pediatric posttraumatic stress disorder

Background: Volumetric imaging research has shown abnormal brain morphology in adults with posttraumatic stress disorder (PTSD) when compared with matched control subjects. In this article, we present brain imaging findings from a study of children with PTSD symptoms. Methods: Twenty-four children between the ages of 7 and 14 with a history of trauma and PTSD symptoms were assessed with the Clinician-Administered PTSD Scale for Children and Adolescents (CAPS-CA). The sample underwent magnetic resonance imaging in a 1.5 T scanner. Brain images were analyzed by raters blind to diagnostic status using well-standardized methods, and images were compared with age- and gender-matched healthy control subjects. Results: The clinical group demonstrated attenuation of frontal lobe asymmetry and smaller total brain and cerebral volumes when compared with the control group. There were no statistically significant differences in hippocampal volume between clinical and control subjects. Conclusions: Frontal lobe abnormalities may occur as a result of PTSD in children or, alternatively, be a risk factor for the development of the syndrome in this age group. The implications of the findings and their consistency with previous research are discussed.

Anomalies of cerebral asymmetry in schizophrenia interact with gender and age of onset: a post-mortem study

In a post-mortem study of cerebral asymmetry in schizophrenia it was found that asymmetry of the length from the frontal pole to the central sulcus measured dorsally over the external surface of the brain on both hemispheres, showed a gender×diagnosis interaction ( p=0.002). Female controls had a left-greater-than-right asymmetry, and the male controls had a right-greater-than-left asymmetry. This pattern was reversed in schizophrenia. The converse effect was observed on a similar measure of the occipito-parietal lobes ( p=0.028). Significant changes were not seen in measures taken around the lateral surface of the hemispheres. Further, within the patient group, the frontal lobe asymmetry was related to age of onset such that leftward asymmetrical brains were associated with a later age of onset than rightward asymmetrical brains ( p=0.0463 for the females; p=0.0162 for the males). The occipito-parietal asymmetry was not related to age of onset. We conclude that the asymmetry of the relative distribution of tissue between frontal and posterior regions of the hemispheres is altered in schizophrenia. The findings also suggest that there is an interaction between gender and cerebral asymmetry that is critical in determining age of onset.

Mathematical cognitive style and arithmetic sign comprehension: A study of EEG alpha and theta activity

The localization of arithmetic sign comprehension was investigated using EEG spectral parameters as indicators of cortical engagement. Right-handed male subjects were selected on the basis of scores on the Mathematics Cognitive Style Survey and assigned to 2 groups, a ‘left hemisphere oriented (LHO)’ ( N = 9) and ‘right hemisphere oriented (RHO)’ ( N = 9) group. Subjects were presented with 4 conditions, a motoric baseline condition, two arithmetic fact retrieval tasks employing either a sign operator or verbal operator and a sign comprehension task which required subjects to fill in a missing sign (e.g. 6 ? 4 = 24). Both across subject correlational analysis of EEG alpha 1 asymmetry and performance as well as within subject analysis of condition means indicated a somewhat unique contribution of the right hemisphere to sign comprehension. LHO subjects exhibited greater relative left mid-temporal lobe activation than RHO subjects but less relative left frontal activation (theta band) than RHO subjects during the verbal operator task. It was tentatively concluded that this frontal lobe asymmetry difference was due to a mismatch in strategy preference and coding requirements among RHO subjects.

Reduced frontal and occipital lobe asymmetry on the CT-scans of schizophrenic patients. Its specificity and clinical significance

Frontal and occipital lobe width were determined in the computed tomographic (= CT) scans of 135 schizophrenic patients, 158 neuropsychiatrically healthy and 102 psychiatric control subjects, including patients with affective psychosis, neurosis and schizoaffective psychosis. Most healthy right handed subjects demonstrate a relative enlargement of the right frontal as well as left occipital lobe compared to the oposite hemisphere. These normal frontal and occipital lobe asymmetries were selectively reduced in schizophrenics (f.: 5%, p <.0005; o.: 3%, p <.05), irrespective of the psychopathological subgroup. Schizophrenic neuroleptic non-responders revealed a significant reduction of frontal lobe asymmetry (3%, p <.05), while no correlation between BPRS-subscores and disturbed cerebral laterality could be detected. In sum the present study demonstrates disturbed cerebral lateralisation in schizophrenic patients supporting the hypothesis of interrupted early brain development in schizophrenia.