Metastudie zu Geschlechterunterschieden in der Gehirnstruktur

Eine interessante Metastudie hat verschiedene Studien zu Geschlechterunterschieden in der Gehirnstruktur ausgewertet:

Highlights

• This is the first meta-analysis of sex differences in the typical human brain.
• Regional sex differences overlap with areas implicated in psychiatric conditions.
• The amygdala, hippocampus, planum temporale and insula display sex differences.
• On average, males have larger brain volumes than females.
• Most articles providing sex differences in volume are in the ‘mature’ category.

Abstract
The prevalence, age of onset, and symptomatology of many neuropsychiatric conditions differ between males and females. To understand the causes and consequences of sex differences it is important to establish where they occur in the human brain. We report the first meta-analysis of typical sex differences on global brain volume, a descriptive account of the breakdown of studies of each compartmental volume by six age categories, and whole-brain voxel-wise meta-analyses on brain volume and density. Gaussian-process regression coordinate-based meta-analysis was used to examine sex differences in voxel-based regional volume and density. On average, males have larger total brain volumes than females. Examination of the breakdown of studies providing total volumes by age categories indicated a bias towards the 18–59 year-old category. Regional sex differences in volume and tissue density include the amygdala, hippocampus and insula, areas known to be implicated in sex-biased neuropsychiatric conditions. Together, these results suggest candidate regions for investigating the asymmetric effect that sex has on the developing brain, and for understanding sex-biased neurological and psychiatric conditions.

Quelle:  A meta-analysis of sex differences in human brain structure

Wie man an den Werten sieht, gibt es durchaus deutliche Unterschiede:

Unterschiede Gehirn Mann Frau

Aus der Besprechung:

3.3.1. Regional volume meta-analysis
All 16 studies included in the volume voxel-based meta-analysis included a between-group comparison of GM volume, leading to a total of 264 reported GM foci. Only 4 studies performed a WM volume comparison, with a total of 30 WM foci. Since 30 data points are insufficiently spatially dense to perform a meta-analysis, only a coordinate-based meta-analysis on GM volume is currently possible. The 16 studies provided a total of 2186 brains (49% female) aged between 7 and 80 years old. Because an FDR-correction at voxel-level q = 0.05 gave diffuse spatial results, we opted for a more stringent correction to capture the most reliable group differences. The (FDR q = 0.01) thresholded Z-value was 3.428 for the male > female contrast and 3.616 for the female > male contrast, and results are reported in Table 4 using an extent threshold of 60 continuous voxels.

On average, males have larger grey matter volume in bilateral amygdalae, hippocampi, anterior parahippocampal gyri, posterior cingulate gyri, precuneus, putamen and temporal poles, areas in the left posterior and anterior cingulate gyri, and areas in the cerebellum bilateral VIIb, VIIIa and Crus I lobes, left VI and right Crus II lobes. Females on average have larger volume at the right frontal pole, inferior and middle frontal gyri, pars triangularis, planum temporale/parietal operculum, anterior cingulate gyrus, insular cortex, and Heschl’s gyrus; bilateral thalami and precuneus; the left parahippocampal gyrus and lateral occipital cortex (superior division).

3.3.2. Regional tissue density meta-analysis
Eight of the nine studies (eight of the ten age-matched groups) investigating voxel-based sex differences in brain tissue density performed a GM analysis, with a total of 86 reported foci. Only three performed a WM density analysis with a total of 13 foci again discouraging a meta-analysis. The eight studies provided a total number of 741 brains (53% female), aged between 10 and 81 years. Results are reported (with FDR q = 0.05). Z-values were 3.247 for the male > female contrast and 3.445 for the female > male contrast, reported in Table 4 with an extent threshold of 60 continuous voxels. Areas of higher GM density in males compared to females included the left amygdala, hippocampus, insular cortex, pallidum, putamen, claustrum, and an area in the right VI lobe of the cerebellum. The left frontal pole has significantly higher GM tissue density in females compared to males.

Also eine Vielzahl von Regionen, bei denen Unterschiede erkennbar sind.

vgl. auch:

• Geschlechterunterschiede in den strukturellen Verbindungen des menschlichen Gehirns
• „Das menschliche Gehirnmosaik“: Unterschiede im Gehirn von Mann und Frau
• Unterschiede im Gehirn von Männern und Frauen: Struktur
• Weiße und graue Gehirnzellen und Transsexualität
• Gehirn von Männern und Frauen: Unterschiede und Theorien
• Geschlechtliche Differenzierung des menschlichen Gehirns in Bezug auf geschlechtliche Identität und sexuelle Orientierung
• Wie Geschlechtsunterschiede im Gehirn durch pränatale Hormone entstehen
• Sprache und Unterschiede im Gehirn von Mann und Frau