title: Parsing the phonological loop: activation timing in the dorsal speech stream determines accuracy in speech reproduction.
abstract: Despite significant research and important clinical correlates, direct neural evidence for a phonological loop linking speech perception, short-term memory and production remains elusive. To investigate these processes, we acquired whole-head magnetoencephalographic (MEG) recordings from human subjects performing a variable-length syllable sequence reproduction task. The MEG sensor data were source localized using a time-frequency optimized spatially adaptive filter, and we examined the time courses of cortical oscillatory power and the correlations of oscillatory power with behavior between onset of the audio stimulus and the overt speech response. We found dissociations between time courses of behaviorally relevant activations in a network of regions falling primarily within the dorsal speech stream. In particular, verbal working memory load modulated high gamma power in both Sylvian-parietal-temporal and Broca's areas. The time courses of the correlations between high gamma power and subject performance clearly alternated between these two regions throughout the task. Our results provide the first evidence of a reverberating input-output buffer system in the dorsal stream underlying speech sensorimotor integration, consistent with recent phonological loop, competitive queuing, and speech-motor control models. These findings also shed new light on potential sources of speech dysfunction in aphasia and neuropsychiatric disorders, identifying anatomically and behaviorally dissociable activation time windows critical for successful speech reproduction.
authors.affiliation: Biomagnetic Imaging Laboratory, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California 94143, USA.
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Herman
authors.forename: John F
authors.initials: JF
authors.lastname: Houde
authors.forename: Sophia
authors.initials: S
authors.lastname: Vinogradov
authors.forename: Srikantan S
authors.initials: SS
authors.lastname: Nagarajan
mesh_terms: D000161:Acoustic Stimulation; D001306:Auditory Pathways / Q000502:physiology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008037:Linguistics; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D010700:Phonetics; D011930:Reaction Time / Q000502:physiology; D013067:Speech Perception / Q000502:physiology*; D013223:Statistics as Topic; D013997:Time Factors
references.citation: Cogn Neuropsychol. 2007 Feb;24(1):3-22
references.pmid: 18416481
references.citation: Curr Neurol Neurosci Rep. 2010 Nov;10(6):499-503
references.pmid: 20711691
references.citation: Cereb Cortex. 2009 Sep;19(9):2156-65
references.pmid: 19181696
references.citation: Neuron. 2011 Feb 10;69(3):407-22
references.pmid: 21315253
references.citation: Neuroimage. 2010 Feb 1;49(3):2735-45
references.pmid: 19874898
references.citation: Neuroimage. 2010 Mar;50(1):291-301
references.pmid: 20026224
references.citation: J Cogn Neurosci. 2010 Jul;22(7):1504-29
references.pmid: 19583476
references.citation: Neuropsychology. 2006 Sep;20(5):529-38
references.pmid: 16938015
references.citation: Proc Natl Acad Sci U S A. 2010 Jan 12;107(2):592-7
references.pmid: 20080724
references.citation: Science. 2009 Oct 16;326(5951):445-9
references.pmid: 19833971
references.citation: Neuroimage. 2008 Feb 15;39(4):1788-802
references.pmid: 18155612
references.citation: Nature. 1996 Nov 14;384(6605):159-61
references.pmid: 8906789
references.citation: Am J Psychiatry. 1977 Sep;134(9):966-9
references.pmid: 900305
references.citation: Nat Rev Neurosci. 2007 May;8(5):393-402
references.pmid: 17431404
references.citation: Nat Rev Neurosci. 2009 Sep;10(9):659-69
references.pmid: 19672274
references.citation: Brain Lang. 2011 Dec;119(3):119-28
references.pmid: 21256582
references.citation: J Neurosci. 2011 Mar 30;31(13):5013-25
references.pmid: 21451039
references.citation: Neuron. 2003 Jun 5;38(5):831-42
references.pmid: 12797966
references.citation: J Speech Hear Res. 1985 Sep;28(3):455-62
references.pmid: 4046587
references.citation: Arch Gen Psychiatry. 2007 Mar;64(3):286-96
references.pmid: 17339517
references.citation: Curr Biol. 2010 Feb 23;20(4):R136-40
references.pmid: 20178752
references.citation: Nat Neurosci. 2009 Jun;12(6):718-24
references.pmid: 19471271
references.citation: J Cogn Neurosci. 2008 May;20(5):762-78
references.pmid: 18201133
references.citation: Comput Intell Neurosci. 2011;2011:758973
references.pmid: 21437174
references.citation: Cereb Cortex. 2011 Feb;21(2):459-66
references.pmid: 20566580
references.citation: Neuron. 2011 Oct 20;72(2):385-96
references.pmid: 22017995
references.citation: IEEE Trans Biomed Eng. 2004 Oct;51(10):1726-34
references.pmid: 15490820
references.citation: Neuroimage. 2003 Aug;19(4):1589-601
references.pmid: 12948714
references.citation: Front Hum Neurosci. 2011 Oct 25;5:82
references.pmid: 22046152
references.citation: J Cogn Neurosci. 2011 Apr;23(4):961-77
references.pmid: 20350182
references.citation: Trends Cogn Sci. 2000 Nov 1;4(11):417-423
references.pmid: 11058819
references.citation: Annu Rev Clin Psychol. 2005;1:321-53
references.pmid: 17716091
references.citation: Neuroimage. 2008 May 1;40(4):1686-700
references.pmid: 18356081
references.citation: Brain. 2004 Jul;127(Pt 7):1479-87
references.pmid: 15090478
references.citation: Proc Natl Acad Sci U S A. 2008 Nov 18;105(46):18035-40
references.pmid: 19004769
references.citation: Brain. 2008 Aug;131(Pt 8):2013-27
references.pmid: 18669510
references.citation: Seizure. 2002 Jun;11(4):278-9
references.pmid: 12027578
references.citation: Clin Schizophr Relat Psychoses. 2011 Jan;4(4):258-61
references.pmid: 21177243
references.citation: Cogn Neuropsychol. 2006;23(1):135-55
references.pmid: 21049325
references.citation: Neuroimage. 2006 Aug 15;32(2):821-41
references.pmid: 16730195
references.citation: Eur Neurol. 1991;31(4):204-11
references.pmid: 1868861