Transcript PPT - MIT
HST 722 / 9.044 “Brain Mechanisms in Hearing and Speech” Course Introduction • Course Web Site (explains everything): http://web.mit.edu/hst.722/www/index.html • An advanced course covering anatomical, physiological, behavioral, and computational studies of the central nervous system relevant to speech and hearing. • Students learn primarily by discussions of scientific papers on topics of current interest. A topic usually consists of one lecture & two class periods devoted to discussions of papers. • Grade and Assignments: – Paper presentations, discussion leading and class participation, 65% – Written & oral assignments associated with Student-chosen Topics, 35% Course Topics • Dorsal cochlear nucleus: Signal processing, multisensory integration and plasticity (Hancock) • Quantitative approaches to the study of neural coding (Delgutte) • Speech motor control (Guenther) • Descending Systems (Brown) • Neuroimaging correlates of human auditory behavior / multisensory integration (Melcher) • Student Topics: Initial Presentations • Language processing I: Cortical representation (Caplan) • Language processing II: Auditory Processing Disorders (Melcher and others) • Student Topics: Final Presentations Most auditory nuclei are located near dorsal surface of brainstem Auditory Structures • 8N: 8th Nerve • CN: Cochlear Nucleus • LL: Lateral Lemniscus • IC: Inferior Colliculus • SC: Superior Colliculus • ICO: Commissure of IC • BIC: Brachium of IC • MGB: Medial Geniculate Body • AI: Primary Auditory Cortex Other Structures • ICM: Cerebellum • 5N; Trigeminal Nerve Cat Aitkin (1986) The ascending auditory pathway Descending pathway roughly parallels ascending pathway Dorsal cochlear nucleus: Signal processing, multisensory integration and plasticity (Hancock) DCN Layers: Complex circuitry of the Dorsal Cochlear Nucleus: cartwheel granule Somatosensory stellate golgi ? vertical ? I.C . fusiform giant t auditory nerve D T PVCN N I II III (IV,V) Quantitative methods for studies of neural coding (Delgutte) Intensity DL Discharge rate (dB) (sp/sec) Signal detection theory allows rigorous comparisons between neurophysiological and psychophysical data 1000 500 00 20 40 60 80 100 30 Auditory-nerve fibe Hypothetical neuron verifying Weber’s law 20 10 0 0 20 40 60 80 100 Intensity (dB SPL) Descending Systems (Brown) From Schofield and Coomes (2005) Speech motor control (Guenther) QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Neuroimaging correlates of human auditory behavior (Melcher) From Petrides and Pandya (1988) Neuroimaging correlates of human auditory behavior (Melcher) Response Decrease Amygdala Subregions Laterobasal Superficial Left Response Increase to Music Centromedial Right From Ball et al. (2007) Language processing I: Cortical representation (Caplan) From Caplan and Gould (2003) Student Topics • Initial Presentations (about mid-way through the course) – Each student chooses, writes up (about 6 pages), and defends orally (10 min. presentation) a topic germane to hearing / speech – Propose 3-4 papers on this topic that could be discussed at the Final Presentations – We will vote on which several topics to choose for the Final Presentations • Final Presentations (at end of the course) – Each winning topic is presented by a group of students – The group presents the topic and leads the discussion of the papers • Example Student Topics have been Absolute Pitch, Auditory Short-Term Memory, A Gene for Speech?, and Auditory Learning in Songbirds Dorsal Cochlear Nucleus Papers Discussed 9/13: 1. May BJ. Role of the dorsal cochlear nucleus in the sound localization behavior of cats. Hear Res 148: 74-87 (2000). 2. Young ED, Spirou GA, Rice JJ, Voigt HF. Neural organization and responses to complex stimuli in the dorsal cochlear nucleus. Phil Trans Roy Soc London B 336:407-413 (1992) 3. Kanold PO, Young ED. Proprioceptive information from the pinna provides somatosensory input to cat dorsal cochlear nucleus. J Neurosci 21: 7848-7858 (2001). Discussed 9/18: 4. Tzounopoulos T, Kim Y, Oertel D, Trussell LO. Cell-specific, spike timingdependent plasticities in the dorsal cochlear nucleus. Nat Neurosci 7:719-725 (2004). 5. Bell CC. Memory-based expectations in electrosensory systems. Curr Opin Neurobiol 11: 481-487, 2001. 6. Levine RA. Somatic (craniocervical) tinnitus and the Dorsal Cochlear Nucleus hypothesis. Am J Otolaryngol. 20:351-362 (1999)