Biomedical subjects

Richard J Haier

Publications and source records attributed to Richard J Haier.

5 recordsLinked to original sources

PubMed2005

Sex differences in N-acetylaspartate correlates of general intelligence: an 1H-MRS study of normal human brain.

Researchers have long attempted to determine brain correlates of intelligence using available neuroimaging technology including CT, MRI, PET, and fMRI. Although structural and functional imaging techniques are well suited to assess gross cortical regions associated with intelligence, the integrity and functioning of underlying white matter networks critical to coordinated cortical integration remain comparatively understudied. A relatively recent neuroimaging advance is magnetic resonance spectroscopy (MRS) which allows for interrogation of biochemical substrates of brain structure and function in vivo. In this study, we examined twenty-seven normal control subjects (17 male, 10 female) to determine whether N-acetylaspartate (NAA), a metabolite found primarily within neurons, is related to intelligence as assessed by the Wechsler Adult Intelligence Scale-III. Of the three white matter regions studied (i.e., left frontal, right frontal, left occipito-parietal), we found that a model including only left occipito-parietal white matter predicted intellectual performance [F(1,25) = 8.65, P = .007; r2 = .26], providing regional specificity to our previous findings of NAA-IQ relationships. Moreover, we found that a complex combination of left frontal and left occipito-parietal NAA strongly predicted performance in women, but not men [F(2,7) = 21.84, P < .001; adjusted r2 = .82]. Our results highlight a biochemical substrate of normal intellectual performance, mediated by sex, within white matter association fibers linking posterior to frontal brain regions.

Adolescent↗

PubMed2005

The neuroanatomy of general intelligence: sex matters.

We examined the relationship between structural brain variation and general intelligence using voxel-based morphometric analysis of MRI data in men and women with equivalent IQ scores. Compared to men, women show more white matter and fewer gray matter areas related to intelligence. In men IQ/gray matter correlations are strongest in frontal and parietal lobes (BA 8, 9, 39, 40), whereas the strongest correlations in women are in the frontal lobe (BA10) along with Broca's area. Men and women apparently achieve similar IQ results with different brain regions, suggesting that there is no singular underlying neuroanatomical structure to general intelligence and that different types of brain designs may manifest equivalent intellectual performance.

Adolescent↗

PubMed2004

Structural brain variation and general intelligence.

Total brain volume accounts for about 16% of the variance in general intelligence scores (IQ), but how volumes of specific regions-of-interest (ROIs) relate to IQ is not known. We used voxel-based morphometry (VBM) in two independent samples to identify substantial gray matter (GM) correlates of IQ. Based on statistical conjunction of both samples (N = 47; P < 0.05 corrected for multiple comparisons), more gray matter is associated with higher IQ in discrete Brodmann areas (BA) including frontal (BA 10, 46, 9), temporal (BA 21, 37, 22, 42), parietal (BA 43 and 3), and occipital (BA 19) lobes and near BA 39 for white matter (WM). These results underscore the distributed neural basis of intelligence and suggest a developmental course for volume--IQ relationships in adulthood.

Adult↗

PubMed2004

Dissociable brain activation responses to 5-Hz electrical pain stimulation: a high-field functional magnetic resonance imaging study.

BACKGROUND: To elucidate neural correlates associated with processing of tonic aching pain, the authors used high-field (3-T) functional magnetic resonance imaging with a blocked parametric study design and characterized regional brain responses to electrical stimulation according to stimulus intensity-response functions. METHODS: Pain was induced in six male volunteers using a 5-Hz electrical stimulus applied to the right index finger. Scanning sequences involved different levels of stimulation corresponding to tingling sensation (P1), mild pain (P2), or high pain (P3). Common effects across subjects were sought using a conjunction analyses approach, as implemented in statistical parametric mapping (SPM-99). RESULTS: The contralateral posterior/mid insula and contralateral primary somatosensory cortex were most associated with encoding stimulus intensity because they showed a positive linear relation between blood oxygenation level-dependent signal responses and increasing stimulation intensity (P1 < P2 < P3). The contralateral secondary somatosensory cortex demonstrated a response function most consistent with a role in pain intensity encoding because it had no significant response during the innocuous condition (P1) but proportionally increased activity with increasingly painful stimulus intensities (0 < P2 < P3). Finally, a portion of the anterior cingulate cortex (area 24) and supplementary motor area 6 demonstrated a high pain-specific response (P3). CONCLUSIONS: The use of response function modeling, conjunction analysis, and high-field imaging reveals dissociable regional responses to a tonic aching electrical pain. Most specifically, the primary somatosensory cortex and insula seem to encode stimulus intensity information, whereas the secondary somatosensory cortex encodes pain intensity information. The cingulate findings are consistent with its proposed role in processing affective-motivational aspects of pain.

Adult↗

PubMed2003

A voxel-based morphometric study of nondemented adults with Down Syndrome.

Previous structural brain imaging studies of Down Syndrome (DS) have offered important insights into the underlying morphometric aberrations associated with the condition. These previous studies have relied almost exclusively on classic region-of-interest (ROI)-based morphometry, a method in which a finite number of anatomical structures must be defined and delineated a priori. Here we use the fully automated voxel-based morphometry (VBM) approach on 19 nondemented individuals with DS and 11 age-matched controls in order to provide a full-brain assessment of DS morphology. Foci of statistically significant (P < 0.05, corrected for multiple comparisons) reductions in gray matter (GM) tissue were observed in the cerebellum, cingulate gyrus, left medial frontal lobe, right middle/superior temporal gyrus, and the left CA2/CA3 region of the hippocampus. Significant decreases in white matter (WM) tissue were noted throughout the inferior brainstem. Foci of statistically significant (P < 0.05, corrected for multiple comparisons) increases in GM tissue were observed in a superior/caudal portion of the brainstem and left parahippocampal gyrus. Significant increases in WM tissue were noted bilaterally in the parahippocampal gyrus. We also noted significant increases in cerebral spinal fluid in regions suggesting enlarged lateral ventricles in the DS group. While these results are generally consistent with prior ROI-based imaging studies of nondemented DS individuals, the present findings provide additional understanding of the three-dimensional topography of DS morphology throughout the brain. The consistency of these findings with prior imaging reports demonstrates the utility of the VBM technique for investigating the neuroanatomy of DS.

Adult↗