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
Aitkin (1986)
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
CortexOther Structures• ICM: Cerebellum• 5N; Trigeminal Nerve
Cat
The ascending auditory pathway
Descending pathway roughly parallels ascending pathway
N
PVCN
N
I.C.
Somatosensory
TD
??
granule
giantt
fusiform
auditorynerve
stellategolgi
cartwheel
vertical
Dorsal cochlear nucleus: Signal processing, multisensory integration and plasticity (Hancock)
Complex circuitry of the Dorsal Cochlear Nucleus:
DCN Layers:I
II
III (IV,V)
0 20 40 60 80 1000
500
1000
0 20 40 60 80 1000
10
20
30
Intensity (dB SPL)
Dis
char
ge ra
te
(sp/
sec)
Inte
nsity
DL
(dB
) Auditory-nerve fibeHypothetical neuron verifying Weber’s law
Quantitative methods for studies of neural coding (Delgutte)
Signal detection theory allows rigorous comparisons between neurophysiological and psychophysical data
Descending Systems (Brown)
From Schofield and Coomes (2005)
Speech motor control (Guenther)
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Neuroimaging correlates of human auditory behavior (Melcher)
From Petrides and Pandya (1988)
Right
Left
ResponseIncreaseto Music
ResponseDecrease
Laterobasal
Superficial
Centromedial
Amygdala Subregions
Neuroimaging correlates of human auditory behavior (Melcher)
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 B336:407-413 (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 timing-dependent plasticities in the dorsal cochlear nucleus. Nat Neurosci 7:719-725 (2004).5. Bell CC. Memory-based expectations in electrosensory systems. Curr OpinNeurobiol 11: 481-487, 2001.6. Levine RA. Somatic (craniocervical) tinnitus and the Dorsal Cochlear Nucleus hypothesis. Am J Otolaryngol. 20:351-362 (1999)
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