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(Radiology. 2001;220:202-207.)
© RSNA, 2001

Neuroradiology

Temporal Lobe Activation Demonstrates Sex-based Differences during Passive Listening1

Micheal D. Phillips, MD, Mark J. Lowe, PhD, Joseph T. Lurito, MD, PhD, Mario Dzemidzic, PhD and Vincent P. Mathews, MD

1 From the Department of Radiology, Indiana University, UH 0279, 550 N University Pkwy, Indianapolis, IN 46202-5111. Received July 24, 2000; revision requested September 15; revision received November 20; accepted January 16, 2001. Address correspondence to M.D.P. (e-mail: mdphilli@iupui.edu).


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
PURPOSE: To evaluate potential sex differences in temporal lobe activation during the performance of a functional magnetic resonance (MR) imaging passive-listening paradigm.

MATERIALS AND METHODS: Twenty strongly right-handed volunteers (10 men, 10 women) underwent imaging with a 1.5-T machine by using a gradient-echo echo-planar sequence. The task consisted of passive listening to simple narrative text interleaved with same-narrative text played backward. Volumes of interest were drawn around anterior and posterior areas of activation in bilateral temporal lobes. The peak percentage of activation and the percentage of activated voxels at single-voxel significance levels of 10-2, 10-3, and 10-4 within each volume of interest were measured. An asymmetry index A was then calculated for both anterior and posterior volumes of interest such that A = (L - R)/(L + R), where R is either the peak percentage activation or the percentage of activated voxels within the right volume of interest and L is either the peak percentage activation or the percentage of activated voxels within the left volume of interest. The asymmetry indexes were compared between men and women by using a standard t test.

RESULTS: Men showed a significantly higher degree of asymmetric activation than did women in both the anterior and posterior volumes of interest by using peak percentage activation and at all single-voxel significance levels. The degree of activation asymmetry was greater by using single-voxel significance measurements, compared with peak percentage activation measures.

CONCLUSION: Women demonstrate a higher degree of bilateral language representation in temporal lobe regions than do men during passive listening. These findings, combined with the variable results of prior functional MR imaging language studies of sex differences, suggest that they may be task specific.

Index terms: Brain, function • Magnetic resonance (MR), echo planar, 134.121412, 134.121419 • Magnetic resonance (MR), functional imaging, 134.121412, 134.121419


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
The relationship of sex to the cortical representation of language remains unclear. A number of behavioral studies (1–5) suggest differences between men and women in the performance of language tasks. Anatomic and positron emission tomographic (PET) studies (6–18) have demonstrated mixed results, with some studies showing and others not finding sex differences within cortical language regions. Potential sex differences are important for several reasons. They may reflect fundamental differences in neurodevelopment that need to be elucidated to fully understand human language. If sex differences exist, careful attention must be paid to the male-to-female ratio of patients included in studies of the evaluation of language processes, including functional neuroimaging studies. Potential sex differences have more recently become clinically important with the increasing use of functional imaging, specifically functional magnetic resonance (MR) imaging, in presurgical planning.

Several investigators (19–22) have evaluated potential sex differences in cortical language areas by using functional MR imaging. Shaywitz et al (19) examined men and women with functional MR imaging during orthographic, phonologic, and semantic language tasks and reported sex differences in the brain activation pattern for phonologic tasks. A follow-up study (20) by this group confirmed these results for phonologic function and demonstrated sex differences in brain activation for semantic tasks. The existence of sex differences in language at functional MR imaging language studies has been questioned by other investigators. For example, findings in two functional MR imaging studies showed no difference between men and women in word generation (21) or semantic decision tasks (22). To our knowledge, language differences between the sexes have not been studied by using a passive-listening functional MR imaging paradigm.

Our group (23) has developed a passive-listening paradigm that produces asymmetric temporal lobe activation, with predominant activation of the left posterior superior temporal gyrus corresponding to the posterior portion of Brodmann area 22, of the middle portion of the left middle temporal sulcus corresponding to the middle portions of Brodmann areas 21 and 22, and of the left anterior superior temporal gyrus corresponding to the anterior portion of Brodmann area 22. The task is simple to perform and can be applied to a variety of patients to identify temporal lobe language areas.

The purpose of the present study was to evaluate potential sex differences during the performance of our functional MR imaging passive-listening paradigm by comparing the degree of asymmetry in temporal lobe activation between women and men.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Twenty healthy subjects (10 men, 10 women; mean age, 29 years; age range, 21–39 years) underwent imaging with a 1.5-T MR unit (Signa; GE Medical Systems, Milwaukee, Wis). Subjects were selected consecutively from a group of volunteers at the Indiana University Medical School campus, Indianapolis. All subjects except for two (one man and one woman who had completed high school) had completed at least an undergraduate college education. All subjects were right handed as determined with an Edinburgh inventory (24) index score of greater than 60. Informed consent was obtained from all subjects, and all examinations were approved by the institutional review board of our university.

Stimuli were presented through MR imaging–compatible headphones in a block paradigm lasting 320 seconds, with interleaving of 32 seconds on and 32 seconds off. The task consisted of passive listening to simple narrative text played forward (on state) interleaved with the same narrative text played backward (off state). The paradigm was performed twice by each subject. The text was from a popular novel (The Partner by John Grisham) and contained both emotional and imaginable content. Subjects were questioned about the content of the text at the conclusion of imaging.

All subjects were immobilized during data acquisition by using a bite bar made from dental impression compound and mounted to the birdcage radio-frequency coil with hard plastic secured by nonmagnetic metal screws. This method is effective in controlling gross head motion during relatively short (320-second) functional imaging. All data sets were evaluated for subject motion by using the displacement parameter suggested by Jiang et al (25) together with the automated image registration method of Woods et al (26). Data sets were considered motion corrupted if head displacement of 0.4 mm or greater was detected. All motion-corrupted data sets were excluded from analysis. No motion correction was used during the analysis of the data.

Blood oxygen level–dependent images of the whole brain were obtained by using a gradient-echo echo-planar sequence with the following parameters: repetition time msec/echo time msec, 2,000/50; transverse sections, 15; section thickness, 7 mm; intrasection gap, 2 mm; flip angle, 90°; field of view, 24 cm; bandwidth, 125 kHz; and matrix, 64 x 64. Additionally, a whole-head T1-weighted three-dimensional spoiled gradient-recalled echo sequence was obtained for purposes of anatomic registration of functional imaging data, with the following parameters: 35/12; number of contiguous transverse sections, 124; flip angle, 30°; field of view, 22 cm; bandwidth, 32 kHz; and matrix, 256 x 128.

For each patient, a single data set obtained with a single performance of the paradigm was used for analysis. Data from the first performance of the paradigm were used except when they were motion corrupted. The first 11 of the 160 images in each group were discarded to account for presaturation and hemodynamic delay effects. A Hamming spatial filter was applied to each raw image, resulting in a threefold improvement in the signal-to-noise ratio (27). The functional MR imaging time series at each pixel was fit to a boxcar reference function, a slope, and an intercept by using a least-squares method (28). A Student t statistic (the ratio of the fit amplitude to its error) for each pixel was used to generate activation maps. Statistical maps were interpolated to 256 x 256 x 256 voxels and transformed into a Talairach space (29).

Spherical volumes of interest (VOIs) of uniform size were drawn around an anterior (middle portion of the middle temporal sulcus and anterior superior temporal gyrus) and a posterior (posterior superior temporal gyrus) area of activation in bilateral temporal lobes (Fig 1). The same neuroradiologist (M.D.P.) placed the VOIs and positioned them to encompass areas of activation seen on the 10-3 significance threshold map. All subjects had both anterior and posterior left temporal activation. In cases in which right temporal activation was not present, the left-sided VOIs were reflected across the midline to produce the appropriate right-sided VOI.



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  		Figure 1. Transverse (left) and coronal (right) activation maps for one female subject, with a threshold value of 10-3, show anterior (top row) and posterior (bottom row) areas of activation. Spherical VOIs were drawn around areas of activation to perform threshold-dependent and threshold-independent measures of activation.

 
The peak percentage activation was then determined for each VOI in the following manner. Percentage activation maps were generated on a voxel-by-voxel basis such that the percentage activation was equal to the average difference in signal between activation and control states divided by the average baseline value multiplied by 100. Peak percentage activation was defined as the value of the voxel with the greatest percentage activation within a given VOI. This method was used to provide a threshold-independent measure of activation. Meaningful measurements of the peak percentage activation require relatively smooth activation data within the VOI (ie, uniform noise characteristics across all the voxels within the VOI). Figure 2 shows a contour map of the activation data from a typical VOI demonstrating the smooth behavior of the data.



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  		Figure 2. Contour map of the activation data from a single transverse section through a typical posterior VOI demonstrates the relatively smooth nature of the activation data. The x and y coordinates indicate position of the voxel in the x-y plane, and the z coordinate indicates the single-voxel student t value multiplied by 100.

 
Activation maps were generated with single-voxel significance values of 10-2, 10-3, and 10-4, and the percentage of activated voxels within each VOI was calculated at each of the significance levels. This method is similar to the threshold-dependent approaches used by previous investigators (19–22). Combined data activation maps for men and women were constructed by separately summing t scores of voxels within the Talairach-transformed individual maps for men and women. A threshold of 10-10 was then applied to the combined activation maps.

An asymmetry index A was then calculated for both anterior and posterior regions of activation, such that A = (L - R)/(L + R), where R is either the peak percentage activation or the percentage of activated voxels within the right VOI and L is either the peak percentage activation or the percentage of activated voxels within the left VOI. The asymmetry indexes for anterior and posterior temporal lobe regions of activation were compared between men and women by using a standard t test.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
All subjects were able to complete at least one session of the forward-versus-backward listening task and were able to recount details of the text at completion of imaging. In only one subject was the first data set motion corrupted at the imaging session; for this patient, the data set from the second performance of the paradigm was used for analysis.

The results for the asymmetry index A in the posterior and anterior VOIs are shown in the Table. Men demonstrated a significantly greater degree of asymmetric temporal lobe activation than did women in both the posterior and anterior VOIs. Figure 3 shows combined activation maps for both men and women. Significant differences were found by using both peak percentage activation and significance threshold methods of measurement. For both men and women, the value of A in the posterior VOI was greater when measured by using significance threshold measurements compared with peak percentage activation measurements (Table). The implications of this finding are discussed next.


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  		Assymetry Index A Measurement for VOIs

 


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  		Figure 3. Combined subject activation data for 10 men (top row) and 10 women (bottom row) show both anterior and posterior temporal lobe activation at a threshold of 10-10 (see color bar, lower right). Men demonstrated markedly asymmetric activation, whereas women tended to show more symmetric temporal lobe activation.

 

   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
Sex differences in language performance have been evaluated in a multitude of behavioral studies. These studies (1,2,5) suggest that women, on the whole, tend to have slightly better verbal skills than do men. Specifically, tests of verbal fluency and speech production show clear differences favoring women (2,3,5). Tests of other tasks, such as vocabulary skills, verbal analogies, and reading comprehension, show fewer consistent differences (1,4). Additionally, hemispheric language lateralization differences between men and women have been demonstrated by using a variety of behavioral techniques with mixed results, as noted in Frost et al (22). Questions remain as to the potential neuroanatomic and/or neurophysiologic substrate that produces these differences in language task performance.

Neuroanatomic studies of language-related regions with gross anatomic specimens (6,7), morphometric studies with MR imaging (8–10), and studies of lesions (11–14) have yielded variable results. Several investigators have demonstrated sex differences in the asymmetry of the planum temporale. Right-handed men typically show a greater degree of asymmetry between right and left temporal lobes; they have a larger planum temporale region in the left temporal lobe than do right-handed women (6–8). Studies of recovery after stroke have shown differences in the incidence of aphasia between men and women (11,12). It should be noted, however, that there are multiple examples in the literature that demonstrate no differences between men and women by using techniques similar to those in the studies discussed previously (9,10,13,14,30). The apparent contradictory nature of the results may reflect differences in the techniques used and inherent difficulties in producing truly objective (non–user-dependent) measurements of the brain regions involved.

Despite a large body of data regarding potential behavioral and anatomic differences between the sexes, there is relatively little neuroimaging data. The neuroimaging data available have also demonstrated variable results with respect to sex. Several PET studies have demonstrated sexual differences during the performance of language tasks. Men demonstrate a higher degree of lateralization of activity to the left of the lateral cerebral sulcus region (regions surrounding the sylvian fissure) during the performance of tasks requiring generation of past-tense verbs (17) and spelling of whole words (15). Other PET studies, however, have shown little or no differences between the sexes with use of word-stem completion tasks, verb-generation tests (18), and tests involving the phonologic and semantic aspects of reading (16).

Similarly, only a handful of functional MR imaging studies have been performed in which a comparison was made of activation patterns between the sexes during the performance of language tasks, again with mixed results. Shaywitz et al (19) examined 38 (19 men, 19 women) right-handed subjects with functional MR imaging during line-pair orientation discrimination (control), letter-case discrimination (orthographic), phonologic (nonword rhyming), and verb-noun discrimination (semantic) tasks. All stimuli were presented visually. When phonologic function was isolated, men showed left-hemisphere lateralization of brain activation, whereas women did not demonstrate hemispheric lateralization. A follow-up study (20) by this group confirmed these results for phonologic function and showed that there was greater left-hemisphere lateralization for men than for women for all tasks combined.

Another observation was that men showed more extensive activation with semantic tasks than with phonologic tasks, but women showed no difference in the extent of activation for these two language subcomponents. Their conclusion was that phonologic and semantic networks overlap more in women than in men (20). Other investigators, however, have not shown significant sex differences by using functional MR imaging experiments with language. A large study by Frost et al (22) that involved 100 patients (50 men, 50 women) showed no sexual differences in the performance of a language task that was used to compare auditory semantic monitoring with tone monitoring. Additionally, van der Kallen et al (21) saw no sex differences in the performance of a word-generation task.

The present study demonstrated significant differences in activation between men and women during the performance of a passive-listening task. Specifically, men performing our task showed greater lateralization of activity to the left temporal lobe than did women. It is unclear how these results relate to the findings of prior studies involving functional MR imaging and sex differences.

One potential explanation of the varied functional MR imaging results is that sexual differences may be task specific. The experience with behavioral studies suggests that sex differences are task dependent. There are marked differences among the tasks used in prior functional MR imaging studies (19–22), and the task used in the present study differs substantially from those used in any of these studies. Our findings, combined with those of others who used different language tasks, suggest that individual language tasks may produce different results with respect to sex. The presence of task-dependent sexual differences in functional MR imaging activation has important implications regarding the development and use of functional MR imaging techniques to study language. Specifically, task-dependent sexual differences would require all newly developed functional MR imaging paradigms to be tested for potential sex differences prior to their application in clinical or research settings.

Another potential reason for the differing results among functional MR imaging studies is the presence of possible experiment-based bias introduced by the methods used to measure asymmetries. All the studies previously discussed relied on region-of-interest analysis of significance-threshold maps to assess the degree of functional MR imaging activation in response to a particular language task; this method is similar to our method with the use of percentage of activated pixels. The significance threshold used varied among these studies.

As illustrated in the Table, the asymmetry measured in this way depends on the chosen significance threshold. The Table shows that the measured asymmetry increases systematically as the threshold increases. It is difficult to assess the significance of the difference in asymmetry measured for each threshold because the numbers are highly correlated. The significance threshold is used to ensure that the probability is high that only pixels from truly activated brain regions are used to assess the asymmetry. The probability that a given significance threshold excludes a truly active pixel from the calculation depends on the specific experimental parameters and imaging unit characteristics. It will vary according to the experimental design and experimental sites. Thus, asymmetries measured by using threshold data may introduce experiment-specific biases that may make results of individual studies difficult to reproduce.

The passive-listening paradigm used in the present study has some limitations. Specifically, the task involves no response on the part of the subject during imaging to ensure uniform task performance. Further, although all subjects were able to answer general questions regarding characters and events in the text at the completion of imaging, a standardized formal test of story comprehension was not performed. Additionally, the passive-listening task used in the present study was not specifically directed toward one component of language but rather reflects a combination of subcomponents that are included in language comprehension. Hence, the findings in the present study do not lend themselves to an evaluation of potential sex differences within specific components of language, such as phonologic or semantic processing.

The emotional content of the text that was chosen to engage the attention of the reader may represent an additional confounding factor. It is possible that some of the differences seen in the present study reflect differences in the emotional and cognitive reaction to material within the text. This is unlikely, given that the regions evaluated are thought to be responsible for language function of a lower order. The advantage of the task, however, is that it is simple for both subjects and technologists to perform and requires little specialized equipment. Additionally, it produces a robust, reproducible activation within temporal lobe regions known to be involved in language comprehension and can be applied in research and clinical settings.

In conclusion, the results of the present study suggest significant differences in the degree of asymmetry of temporal lobe activation between men and women during the performance of a passive-listening task. These findings, along with the results of other investigations, suggest that sex differences in functional MR imaging activation patterns in language paradigms may be task dependent. The presence of possible task-specific differences between men and women obligates investigators to evaluate individual functional MR imaging language paradigms for sex differences before applying them in clinical and research settings.


   FOOTNOTES
 
Abbreviation: VOI = volume of interest

Author contributions: Guarantor of integrity of entire study, M.D.P.; study concepts and design, all authors; literature research, M.D.P., V.P.M.; experimental studies, M.D.P., M.D., J.T.L.; data acquisition, M.D.P., M.D., J.T.L., M.J.L.; data analysis/interpretation, all authors; statistical analysis, M.D.P., M.D., M.J.L.; manuscript editing, M.D., M.J.L., J.T.L., V.P.M.; manuscript preparation, definition of intellectual content, revision/review, and final version approval, all authors.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 

  1. Hyde JS, Linn MC. Gender differences in verbal ability: a meta-analysis. Psychol Bull 1988; 104:53-69.[CrossRef]
  2. Halpern DF. Sex differences in cognitive abilities Hillsdale, NJ: Earlbaum, 1992.
  3. Capitani E, Laiacona M, Basso A. Phonetically cued word-fluency, gender differences and aging: a reappraisal. Cortex 1998; 34:779-783.[Medline]
  4. Clark E, Gardner MK, Brown G, Howell RJ. Changes in analogical reasoning in adulthood. Exp Aging Res 1990; 16:95-99.[Medline]
  5. Kimura D. Sex differences in the brain. Sci Am 1992; 267:118-125.[Medline]
  6. Wada JA, Clarke R, Hamm A. Cerebral hemispheric asymmetry in humans: cortical speech zones in 100 adults and 100 infant brains. Arch Neurol 1975; 32:239-246.[Abstract/Free Full Text]
  7. Witelson SF, Kigar DL. Sylvian fissure morphology and asymmetry in men and women: bilateral differences in relation to handedness in men. J Comp Neurol 1992; 323:326-340.[CrossRef][Medline]
  8. Kulynych JJ, Vladar K, Jones DW, Weinberger DR. Gender differences in the normal lateralization of the supratemporal cortex: MRI surface-rendering morphometry of Heschl’s gyrus and the planum temporale. Cereb Cortex 1994; 4:107- 118.[Abstract/Free Full Text]
  9. Jancke L, Schlaug G, Huang Y, Steinmetz H. Asymmetry of the planum parietale. Neuroreport 1994; 5:1161-1163.[Medline]
  10. Habib M, Robichon F, Levrier O, Khalil R, Salamon G. Diverging asymmetries of temporo-parietal cortical areas: a reappraisal of Geschwind/Galaburda theory. Brain Lang 1995; 48:238-258.[CrossRef][Medline]
  11. McGlone J. Sex differences in the cerebral organization of verbal functions in patients with unilateral brain lesions. Brain 1977; 100:775-793.[Free Full Text]
  12. Kimura D. Sex differences in cerebral organization for speech and praxic functions. Can J Psychol 1983; 37:19-35.[Medline]
  13. Kertesz A, Sheppard A. The epidemiology of aphasic and cognitive impairment in stroke: age, sex, aphasia type and laterality differences. Brain 1981; 104:117-128.[Free Full Text]
  14. Kertesz A, Benke T. Sex equality in intrahemispheric language organization. Brain Lang 1989; 37:401-408.[CrossRef][Medline]
  15. Wood F, Flowers D, Naylor C. Cerebral laterality in functional neuroimaging. In: Kitterle F, eds. Cerebral laterality: theory and research. Hillsdale, NJ: Earlbaum, 1991; 103-115.
  16. Price CJ, Moore CJ, Friston KJ. Getting sex into perspective (abstr). Neuroimage 1996; 3:S586.[CrossRef]
  17. Jaeger JJ, Lockwood AH, Van Valin RD, Jr, Kemmerer DL, Murphy BW, Wack DS. Sex differences in brain regions activated by grammatical and reading tasks. Neuroreport 1998; 9:2803-2807.[Medline]
  18. Buckner RL, Raichle ME, Petersen SE. Dissociation of human prefrontal cortical areas across different speech production tasks and gender groups. J Neurophysiol 1995; 74:2163-2173.[Abstract/Free Full Text]
  19. Shaywitz BA, Shaywitz SE, Pugh KR, et al. Sex differences in the functional organization of the brain for language. Nature 1995; 373:607-609.[CrossRef][Medline]
  20. Pugh KR, Shaywitz BA, Shaywitz SE, et al. Cerebral organization of component processes in reading. Brain 1996; 119:1221-1238.[Abstract/Free Full Text]
  21. van der Kallen BF, Morris GL, Yetkin FZ, van Erning LJ, Thijssen HO, Haughton VM. Hemispheric language dominance studied with functional MR: preliminary study in healthy volunteers and patients with epilepsy. AJNR Am J Neuroradiol 1998; 19:73-77.[Abstract]
  22. Frost JA, Binder JR, Springer JA, et al. Language processing is strongly left lateralized in both sexes: evidence from functional MRI. Brain 1999; 122:199-208.[Abstract/Free Full Text]
  23. Phillips MD, Lowe MJ, Lurito JT, Mathews VP, Dzemidzic M. A novel passive listening paradigm for selective BOLD activation of Wernicke’s area (abstr). Radiology 1999; 213(P):183.
  24. Oldfield RC. The assessment and analysis of handedness: the Edinburgh inventory. Neuropsychologia 1971; 9:97-113.[CrossRef][Medline]
  25. Jiang A, Kennedy DN, Baker JR, et al. Motion detection and correction in functional MR imaging. Hum Brain Mapp 1995; 3:224-235.[CrossRef]
  26. Woods RP, Cherry SR, Mazziotta JC. Rapid automated algorithm for aligning and reslicing PET images. J Comput Assist Tomogr 1992; 16:620-633.[Medline]
  27. Lowe MJ, Sorenson JA. Spatially filtering functional magnetic resonance imaging data. Magn Reson Med 1997; 37:723-729.[Medline]
  28. Lowe MJ, Russell DP. Treatment of baseline drifts in fMRI time series analysis. J Comput Assist Tomogr 1999; 23:463-473.[CrossRef][Medline]
  29. Talairach J, Tournoux P. Co-planar stereotaxic atlas of the human brain: an approach to medical cerebral imaging New York, NY: Thieme, 1988.
  30. Hier DB, Yoon WB, Mohr JP, Price TR, Wolf PA. Gender and aphasia in the Stroke Data Bank. Brain Lang 1994; 47:155-167.[CrossRef][Medline]



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