580.626 Structure and Function of the Auditory and Vestibular Systems (Fall 2014) Auditory Cortex (1) Prof. Xiaoqin Wang Laboratory of Auditory Neurophysiology Department of Biomedical Engineering Johns Hopkins University web1.johnshopkins.edu/xwang
Outline Lecture 1: Anatomy of auditory thalamus and cortex a) Subdivisions of medial geniculate body (MGB) b) Multiple fields of auditory cortex c) Thalamo-cortial and cortico-cortical connections Lecture 2: Tonotopic organization and stimulus selectivity a) Tonotopic organization of auditory cortex b) Firing patterns and tuning to preferred stimulus Lecture 3: Temporal processing a) Temporal-to-rate transformation in A1 b) Temporal-to-rate transformation outside A1 Lecture 4: Spectral, intensity and spatial processing a) Spectral processing b) Intensity processing c) Spatial processing Lecture 5: Complex sound processing a) Pitch and harmonicity processing b) Vocalization processing
What is unique about the auditory system? Auditory cortex (7) Thalamus (6) 1) Longer subcortical pathway 2) Spectrally overlapping, timevarying input signal 3) Sounds entering the ear from anywhere at anytime 4) Hearing-speaking: sensorymotor processing Inferior colliculus (5) Cochlear nucleus (3) Auditory-nerve (2) MSO, LSO (4) [binaural processing] Sounds Cochlea (1) Left Ear Right Ear
More spiking synapses in subcortical nuclei Visual Auditory Graded transmission spiking spiking 1 2 1 3
New World Monkey (Callithrix jacchus common marmoset) Auditory cortex Old World Monkey (Cercopithecus) Human Organization of auditory cortex is largely preserved across primate species Brodmann (1909)
Overall organization of auditory cortex Cat Imig and Reale (1980) Primate (Owl monkey) Morel and Kaas (1992) R C C R
The main ascending auditory pathway from IC to MGB to auditory cortex Auditory Cortex Medial Geniculate Body (MGB) Inferior Colliculus Yost and Nielsen (1977)
Main subdivisions of the auditory thalamus Medial Geniculate Body (MGB) Ventral division MGV Dorsal division MGD Medial division MGM Suprageniculate (not shown) SG Myelin stain of marmoset MGB by A. Pistorio (Wang lab)
MGB cyto- and myelo-architecture (cat) Winer et al. (2001)
MGB cyto- and myelo-architecture (Own monkey) Morel and Kaas (1992)
Electrode path for recording from marmoset MGB in vivo Bartlett (Wang lab)
MGV responds to tones with sharply tuned, short latency responses MGV receives input from the central nucleus of the IC Calford and Aitkin (1983)
MGD responses to tones are broadly tuned, long-latency MGD receives mainly from extralemniscal IC Calford and Aitkin (1983)
Cerebral cortex has six layers Cortical-cortical communication" (Figure from Principles of Neural Science by Kandel et al.) Subcortical nuclei" Thalamus"
Information flow within the cerebral cortex Cortical-cortical communication" (Figure from Principles of Neural Science by Kandel et al.) Subcortical nuclei" Thalamus"
Projections from MGB to auditory cortex (cat) Huang and Winer (2000)
Summary of thalamocortical projection patterns Huang and Winer (2000)
Comparison of thalamocortical projections Huang and Winer (2000)
Corticothalamic projections are reciprocal with thalamocortical inputs but also more widespread Winer et al. (2001)
Wang (2007)
Overall organization of auditory cortex (Owl monkey) Morel and Kaas (1992)
Connections between auditory cortex and other areas Morel and Kaas (1992)
Projections of auditory cortex to frontal cortex Morel and Kaas (1992)
Rostral pole of STG has auditory function Morel and Kaas (1992)
Auditory cortex - MGB projections Morel and Kaas (1992)
Auditory cortex - MGB projections Morel and Kaas (1992)
Auditory cortex to IC projections (Owl monkey) Morel and Kaas (1992)
Auditory cortex to IC projections (cat) MGV injection SG/MGM injection LeDoux et al. (1985)
Connections of primate auditory cortex (Owl monkey) Frontal cortex connections Thalamic connections Morel and Kaas (1992)
Belt and parabelt projections to prefrontal cortex (Macaque monkey) Romanski et al. (1999)
Belt and parabelt projections to prefrontal cortex (Macaque monkey) Romanski (2004)
Cortical areas related to the processing of auditory, auditory/visual, and visual stimuli (Macaque monkey) Poremba et al. (2003)
Suggested readings: 1. Huang CL, Winer JA. Auditory thalamocortical projections in the cat: laminar and areal patterns of input. J Comp Neurol. 2000 Nov 13;427(2):302-31. 2. Winer JA, Diehl JJ, Larue DT. Projections of auditory cortex to the medial geniculate body of the cat. J Comp Neurol. 2001 Jan 29;430(1):27-55. 3. Morel A1, Kaas JH. Subdivisions and connections of auditory cortex in owl monkeys. J Comp Neurol. 1992 Apr 1;318(1):27-63. 4. Romanski LM, Bates JF, Goldman-Rakic PS. Auditory belt and parabelt projections to the prefrontal cortex in the rhesus monkey. J Comp Neurol. 1999 Jan 11;403(2):141-57. 5. Poremba A, Saunders RC, Crane AM, Cook M, Sokoloff L, Mishkin M. Functional mapping of the primate auditory system. Science. 2003 Jan 24;299(5606):568-72.