DISORDERS OF AUDITORY PROCESSING DAY 21 – OCT 15, 2013 Brain & Language LING NSCI Harry Howard Tulane University

Course organization The syllabus, these slides and my recordings are available at If you want to learn more about EEG and neurolinguistics, you are welcome to participate in my lab. This is also a good way to get started on an honor's thesis. The grades are posted to Blackboard. 10/16/13Brain & Language - Harry Howard - Tulane University 2

REVIEW and some new stuff 10/16/13Brain & Language - Harry Howard - Tulane University 3

Agnosia VisionAudition Can not recognize objects in general visual agnosiaauditory agnosia Can not recognize linguistic objects alexia (word blindness) speech agnosia (pure word deafness) Can not recognize human objects prosopagnosia (face blindness) phonagnosia 10/16/13Brain & Language - Harry Howard - Tulane University 4 An impairment in which a patient fails to recognize a stimulus in a sensory modality, although perception in the modality is unimpaired. By “perception”, we mean the subcortical processing of the modality.

Summary Non-speech sounds VoicesSpeechCause Cortical deafness ✖✖✖ bilateral lesions to A1 Auditory agnosia ✖✔✔ damage to feature detectors in A2 & A3 Pure word deafness ✔✔✖ damage to phonetic feature detectors or speech motor loop Phonagnosia ✔✖✔ damage to inferior and lateral parietal regions of the RH 10/16/13Brain & Language - Harry Howard - Tulane University 5

MORE ABOUT AUDITORY PROCESSING Ingram §8 10/16/13Brain & Language - Harry Howard - Tulane University 6

DORSAL VS. VENTRAL PROCESSING 10/16/13Brain & Language - Harry Howard - Tulane University 7

Dorsal ~ ventral? 10/16/13Brain & Language - Harry Howard - Tulane University 8

What's this? 10/16/13Brain & Language - Harry Howard - Tulane University 9

Dorsal ~ ventral streams in vision 10/16/13Brain & Language - Harry Howard - Tulane University 10

10/16/13Brain & Language - Harry Howard - Tulane University 11 Hickok & Poeppel's model on the brain

10/16/13Brain & Language - Harry Howard - Tulane University 12 Hickok & Poeppel’s localization of speech What/Ventral: sound- meaning interface maps sound onto meaning includes superior temporal sulcus and ultimately the posterior inferior temporal lobe (portions of the middle temporal gyrus and inferior temporal gyrus) strongly lateralized to LH Where/Dorsal: auditory-motor interface maps sound onto representations of speech articulators deep within the posterior aspect of Sylvian fissure at the boundary between the parietal and temporal lobes: area Spt (Sylvian – parietal – temporal) the Spt projects to Broca's area, the motor face area, and a more dorsal premotor site less strongly lateralized to LH Early speech perception involves auditory-responsive fields in the superior temporal gyrus (STG) bilaterally

10/16/13Brain & Language - Harry Howard - Tulane University 13 Hickok & Poeppel’s model in boxes

10/16/13Brain & Language - Harry Howard - Tulane University 14 Hickok & Poeppel’s model, an example [kæt]

Recall the TRACE II model it may be a model of the dorsal stream 10/16/13Brain & Language - Harry Howard - Tulane University 15

MIRROR NEURONS 10/16/13Brain & Language - Harry Howard - Tulane University 16

Monkey see monkey do 10/16/13Brain & Language - Harry Howard - Tulane University 17

Imitation 10/16/13Brain & Language - Harry Howard - Tulane University 18

Mirror neurons Example of a F5 mirror neuron selectively discharging … (A) during observation of a grasping movement done by the experimenter and (B) during monkey grasping movements. Arrows denote the onset of the movement. Six trials are shown for each condition. 10/16/13Brain & Language - Harry Howard - Tulane University 19

Monkey vs. human brains 10/16/13Brain & Language - Harry Howard - Tulane University 20

What does this have to do with speech? Transcranial magnetic stimulation (TMS) causes neurons in the neocortex under the site of stimulation to depolarize and discharge an action potential. If used in the primary motor cortex, it produces muscle activity referred to as a motor evoked potential (MEP) which can be recorded on electromyography. Ingram discusses two experiments that suggest that listening to speech activates speech-related motor cortices by enhancing LH MEPs under TMS > Hickok & Poepel's area Spt 10/16/13Brain & Language - Harry Howard - Tulane University 21

Disturbances in accessing the recognition lexicon Read Ingram. 10/16/13Brain & Language - Harry Howard - Tulane University 22

NEXT TIME Start Ingram §9. ☞ Go over questions at end of chapter. 10/16/13Brain & Language - Harry Howard - Tulane University 23