Hippocampal and anterior cingulate activation deficits in patients with geriatric depression.

OBJECTIVE: The authors assessed frontotemporal function in patients with geriatric depression, a debilitating and increasingly prevalent disorder that has not been examined with brain activation paradigms. METHOD: Six depressed elderly patients and five healthy comparison subjects underwent high-sensitivity [(15)O]H(2)O positron emission tomography scans during a paced word generation task and a resting condition. RESULTS: Bilateral activation deficits were noted in the dorsal anterior cingulate gyrus and hippocampus of the depressed geriatric patients relative to the comparison subjects. Patients had memory deficits that correlated with lower hippocampal activity during both rest and activation. CONCLUSIONS: These initial findings suggest that hippocampal and dorsal anterior cingulate hypoactivation may constitute contributing neural substrates of geriatric depression. They also suggest that hippocampal dysfunction is related to the memory dysfunction characteristic of this disorder.

Increased anterior cingulate and caudate activity in bipolar mania.

BACKGROUND: Executive control of cognition, emotion, and behavior are disrupted in the manic state of bipolar disorder. Whereas frontal systems are implicated in such dysfunction, the localization of functional brain abnormalities in the manic state is not well understood. METHODS: We utilized a high-sensitivity H(2)(15)0 positron emission tomography technique to investigate regions of increased brain activity in mania, compared to euthymia, in bipolar disorder. RESULTS: The principal findings were manic state-related increased activity in left dorsal anterior cingulate, and left head of caudate. CONCLUSIONS: The findings suggest that the manic state of bipolar disorder may be associated with heightened activity in a frontal cortical-subcortical neural system that includes the anterior cingulate and caudate.

Atrophy of the medial occipitotemporal, inferior, and middle temporal gyri in non-demented elderly predict decline to Alzheimer's disease.

Our goal was to ascertain, among normal elderly and individuals with mild cognitive impairment, which temporal lobe neocortical regions predicted decline to dementia of the Alzheimer's type (DAT). Individuals received an MRI at baseline and a clinical and cognitive evaluation at baseline and follow-up. By using the baseline MRI we assessed the anatomical subdivisions of the temporal lobe: anteromedial temporal lobe (hippocampus and parahippocampal gyrus), medial occipitotemporal (fusiform) gyrus, middle and inferior temporal gyri, and superior temporal gyrus. We studied two groups of carefully screened age- and education-matched elderly individuals: 26 normal elderly (NL) and 20 individuals with mild cognitive impairment (MCI). Fourteen individuals (12 from the MCI group and two from the NL group) declined to DAT within the 3.2-year follow-up interval. We used logistic regression analyses to ascertain whether the baseline brain volumes were useful predictors of decline to DAT at follow-up after accounting for age, gender, individual differences in brain size, and other variables known to predict DAT. After accounting for age, gender, and head size, adding the volume of the anteromedial temporal lobe (the aggregate of hippocampus and parahippocampal gyrus) and an index of global atrophy raised the accuracy of overall classification to 80.4%. However, the ability to detect those individuals who declined (sensitivity) was low at 57%. When baseline medial occipitotemporal and the combined middle and inferior temporal gyri were added to the logistic model, the overall classification accuracy reached 95.6% and, most importantly, the sensitivity rose to 92.8%. These data indicate that the medial occipitotemporal and the combined middle and inferior temporal gyri may be the first temporal lobe neocortical sites affected in AD; atrophy in these areas may herald the presence of future AD among nondemented individuals. No other clinical baseline variables examined predicted decline with sensitivities above 71%. The apolipoprotein APOE epsilon4 genotype was not associated with decline.

Rostral and orbital prefrontal cortex dysfunction in the manic state of bipolar disorder.

OBJECTIVE: This study investigated prefrontal cortex function in the manic state of bipolar disorder. METHOD: High-sensitivity [15O]H2O positron emission tomography and a word generation activation paradigm were used to study regional cerebral blood flow in five manic and six euthymic individuals with bipolar disorder and in five healthy individuals. RESULTS: Decreased right rostral and orbital prefrontal cortex activation during word generation and decreased orbitofrontal activity during rest were associated with mania. CONCLUSIONS: The data support the presence of rostral and orbital prefrontal dysfunction in primary mania. These findings, when seen in the context of the human brain lesion and the behavioral neuroanatomic literatures, may help to explain some of the neurobehavioral abnormalities characteristic of the manic state.

Brain computed tomography in geriatric manic disorder.

BACKGROUND: Excess brain changes in geriatric manic patients have been hypothesized. Few neuroimaging studies are available. METHODS: Brain computed tomography scans in geriatric patients with manic disorder (n = 30) were compared to those in same-age control subjects (n = 18). Ratings of cortical sulcal widening (CSW), lateral ventricle-brain ratio (VBR), and related linear measures were determined. RESULTS: Patients had greater CSW scores (Exact p = .002) and VBR (t = 2.51, df = 46, p < .02) compared to control subjects. CSW was positively associated with age at illness onset (rs = .46, p < .01) and age at first manic episode (rs = .53, p < .005). VBR was poorly correlated with CSW and was not associated with these indices of illness course. CONCLUSIONS: These findings support the need for further investigation of relationships between brain structure and clinical features in geriatric mania.

Effect of subtle neurological dysfunction on response to haloperidol treatment in schizophrenia.

OBJECTIVE: The primary purpose of this study was to assess whether an interaction between subtle neurological impairment and haloperidol plasma level affects treatment response and, if so, the impact on negative symptoms in particular. METHOD: Forty-three schizophrenic and two schizoaffective inpatients diagnosed according to Research Diagnostic Criteria were given, at the end of a 1-week placebo period, a baseline evaluation consisting of the Brief Psychiatric Rating Scale (BPRS), Scales for the Assessment of Positive and Negative Symptoms, Quantified Neurological Scale, and the Simpson-Angus Scale for extrapyramidal side effects. Subjects were randomly assigned to one of three haloperidol plasma ranges and treated for 6 weeks. At the end point the BPRS, Scales for the Assessment of Positive and Negative Symptoms, and Simpson-Angus Scale were readministered. Multiple linear regressions were used to assess the extent to which the interaction between neurological abnormality and haloperidol plasma level predicted the end-point symptoms once the baseline symptoms, neurological abnormality, and haloperidol plasma level were accounted for. RESULTS: Those patients with higher levels of overall abnormality on the Quantified Neurological Scale at baseline and with frontal dysfunction in particular, had, with increasing haloperidol plasma levels, more severe negative symptoms at end point. Neurological dysfunction was not related to end-point positive symptoms. The effect was specific to end-point negative symptoms and was independent of extrapyramidal side effects. CONCLUSIONS: If confirmed, these findings may indicate that relatively intact frontal function is needed for improvement in negative symptoms and that those patients with schizophrenia who have subtle neurological dysfunction should be treated with lower doses of neuroleptics.