Ahmed et al. (2008). Pubertal hormones modulate the addition of new cells to sexually dimorphic brain regions. Ahmed et al. (2008). Pubertal hormones modulate the addition of new cells to sexually dimorphic brain regions. Nature Neuroscience, 11, pp By David Guzman, Alicia Witter, Jordy Serwin, and Michelle Greenberg

Ahmed et al. (2008). Pubertal hormones modulate the addition of new cells to sexually dimorphic brain regions. Sexual Dimorphism of the Brain  Males Localized areas of function Visuospatial tasks Hypothalamus in men contains both aggression and sexual drive Females Diffused areas of function Verbal tasks Corpus Callosum is larger

Ahmed et al. (2008). Pubertal hormones modulate the addition of new cells to sexually dimorphic brain regions. Effect of Hormones on Sexual Dimorphism Genes (chromosomes) determine response to hormones Fetus is female by default SRY gene causes a response to androgens which leads to defeminization of fetus Hormones develop our sex organs, body development, and brains

Ahmed et al. (2008). Pubertal hormones modulate the addition of new cells to sexually dimorphic brain regions. Does it end there? New research shows sexual dimorphism of brain may continue in puberty Brain is not permanently hardwired at birth Gonadal hormones

Ahmed et al. (2008). Pubertal hormones modulate the addition of new cells to sexually dimorphic brain regions. Method Rat brains were viewed in four stages Pre-puberty, Puberty, Mid-puberty, and Adulthood Three sexually dimorphic brain areas Anteroventral petriventricular nucleus of the hypothalamus (AVPV) Sexually dimorphic area of the preoptic area (SDN) Medial amygdala AVPV is larger in females, SDN and Medial Amygdala is larger in males Removal of Gonads (Control)

Ahmed et al. (2008). Pubertal hormones modulate the addition of new cells to sexually dimorphic brain regions. Adapted from Ahmed et al. (2008)

Ahmed et al. (2008). Pubertal hormones modulate the addition of new cells to sexually dimorphic brain regions. Results Cell and Neuron count increase in sexually dimorphic areas of brain Females: More cell growth in AVPV Males: More cell growth in SDN and Medial Amgydala Removal of Gonads (gonodal hormones) prevented cell and neuron growth Gonadal hormones are necessary in cell growth for function and development of the sexually dimorphic areas of the brain during adolescence and emerging adulthood.

Ahmed et al. (2008). Pubertal hormones modulate the addition of new cells to sexually dimorphic brain regions. Critical Review Strengths Focus on sexually dimorphic areas of the brain. Gonads had a significant impact on development Evidence corresponds with behavior and properties we see. Such as influx of hormones in puberty that we know create secondary sex characteristics might also effect the brain Evidence is objective and purely scientific Weaknesses Subjects were rats Cannot be performed on humans as death is necessary to view the hypothalamus More research is needed to see if this relates to humans and their more complex, social behavior