title: Ventromedial prefrontal volume predicts understanding of others and social network size.
abstract: Cognitive abilities such as Theory of Mind (ToM), and more generally mentalizing competences, are central to human sociality. Neuroimaging has associated these abilities with specific brain regions including temporo-parietal junction, superior temporal sulcus, frontal pole, and ventromedial prefrontal cortex. Previous studies have shown both that mentalizing competence, indexed as the ability to correctly understand others' belief states, is associated with social network size and that social group size is correlated with frontal lobe volume across primate species (the social brain hypothesis). Given this, we predicted that both mentalizing competences and the number of social relationships a person can maintain simultaneously will be a function of gray matter volume in these regions associated with conventional Theory of Mind. We used voxel-based morphometry of Magnetic Resonance Images (MRIs) to test this hypothesis in humans. Specifically, we regressed individuals' mentalizing competences and social network sizes against gray matter volume. This revealed that gray matter volume in bilateral posterior frontal pole and left temporoparietal junction and superior temporal sucus varies parametrically with mentalizing competence. Furthermore, gray matter volume in the medial orbitofrontal cortex and the ventral portion of medial frontal gyrus, varied parametrically with both mentalizing competence and social network size, demonstrating a shared neural basis for these very different facets of sociality. These findings provide the first fine-grained anatomical support for the social brain hypothesis. As such, they have important implications for our understanding of the constraints limiting social cognition and social network size in humans, as well as for our understanding of how such abilities evolved across primates.
authors: School of Psychological Sciences, University of Manchester, Manchester, UK. p.lewis@manchester.ac.uk
authors: Penelope A
authors: PA
authors: Lewis
authors: Roozbeh
authors: R
authors: Rezaie
authors: Rachel
authors: R
authors: Brown
authors: Neil
authors: N
authors: Roberts
authors: R I M
authors: RI
authors: Dunbar
references: Neuropsychologia. 2001;39(6):545-55
references: 11257280
references: Neuroscientist. 2007 Dec;13(6):580-93
references: 17911216
references: Neuroimage. 2006 Jan 1;29(1):90-8
references: 16122944
references: Proc Biol Sci. 2007 Feb 22;274(1609):453-64
references: 17476764
references: Neuropsychologia. 2010 Jul;48(9):2586-94
references: 20457166
references: Ann N Y Acad Sci. 2007 Dec;1121:72-86
references: 17846152
references: Brain Res. 2006 Mar 24;1079(1):57-65
references: 16480695
references: Neuroimage. 2007 Apr 15;35(3):1378-84
references: 17376703
references: J Cogn Neurosci. 2004 Dec;16(10):1854-63
references: 15701234
references: Soc Neurosci. 2006;1(3-4):245-58
references: 18633791
references: Neuroimage. 2002 Jul;16(3 Pt 1):696-703
references: 12169253
references: Philos Trans R Soc Lond B Biol Sci. 2007 Apr 29;362(1480):649-58
references: 17301028
references: Brain. 2001 Feb;124(Pt 2):279-86
references: 11157555
references: Cognition. 1983 Jan;13(1):103-28
references: 6681741
references: Cortex. 2009 Nov-Dec;45(10):1119-25
references: 19559409
references: Acta Physiol Hung. 2008 Jun;95(2):131-64
references: 18642756
references: Proc Natl Acad Sci U S A. 2010 Dec 14;107(50):21582-6
references: 21098277
references: Cognition. 1994 Apr-Jun;50(1-3):211-38
references: 8039362
references: Cogn Affect Behav Neurosci. 2008 Dec;8(4):485-97
references: 19033243
references: J Child Psychol Psychiatry. 2007 Dec;48(12):1251-8
references: 18093031
references: Soc Cogn Affect Neurosci. 2009 Dec;4(4):423-8
references: 20035017
references: Ideggyogy Sz. 2008 Mar 30;61(3-4):77-86
references: 18459448
references: Brain. 2009 Mar;132(Pt 3):617-27
references: 18971202
references: Philos Trans R Soc Lond B Biol Sci. 2003 Mar 29;358(1431):459-73
references: 12689373
references: Hum Nat. 2003 Mar;14(1):53-72
references: 26189988
references: Trends Cogn Sci. 2003 Feb;7(2):77-83
references: 12584026
references: Neuroimage. 2003 Aug;19(4):1835-42
references: 12948738
references: Nat Rev Neurosci. 2007 Dec;8(12):976-87
references: 18026167
references: Prog Neuropsychopharmacol Biol Psychiatry. 2007 Jan 30;31(1):41-5
references: 16863674
references: Acta Psychiatr Scand. 2009 Mar;119(3):199-208
references: 19016669
references: Science. 1989 Nov 10;246(4931):827-8
references: 17748711
references: Neuroimage. 2002 Jun;16(2):538-50
references: 12030836
references: Annu Rev Psychol. 2004;55:87-124
references: 14744211
references: Neuroimage. 2001 Jul;14(1 Pt 1):21-36
references: 11525331
references: Psychol Sci. 2006 Aug;17(8):692-9
references: 16913952
references: Neuroimage. 2002 Sep;17(1):29-46
references: 12482066
references: Neuron. 2006 May 18;50(4):531-4
references: 16701204
references: Hum Nat. 1995 Sep;6(3):273-90
references: 24203093
references: Neuropsychologia. 2000;38(1):11-21
references: 10617288
references: Proc Biol Sci. 2007 Oct 7;274(1624):2429-36
references: 17652066
references: J Cogn Neurosci. 2009 Mar;21(3):489-510
references: 18510452
references: J Cogn Neurosci. 2004 Dec;16(10):1805-17
references: 15701230
references: Hum Brain Mapp. 2009 Mar;30(3):829-58
references: 18381770
references: Neuroimage. 2004 Nov;23(3):967-74
references: 15528097
references: Neuroimage. 2005 Dec;28(4):787-96
references: 15964210
references: Neuroreport. 2001 Aug 8;12(11):2433-8
references: 11496124
references: J Cogn Neurosci. 2000 Nov;12(6):913-23
references: 11177413
references: Neuroreport. 2008 Jun 11;19(9):921-5
references: 18520994
references: Proc Biol Sci. 2005 Feb 22;272(1561):439-44
references: 15734699
references: Evolution. 2007 Dec;61(12):2811-21
references: 17908248
references: J Cogn Neurosci. 2010 Jun;22(6):1112-23
references: 19580387
references: Am J Psychiatry. 2006 Jul;163(7):1290-2
references: 16816240
references: Neuropsychologia. 2010 Oct;48(12):3554-62
references: 20713074
references: Trends Cogn Sci. 2007 Feb;11(2):49-57
references: 17188554