LA LATERALIZACIÓN DEL SISTEMA FÓNICO 2 23 FEB 2011 – DÍA 19 Neurolingüística del español SPAN 4270 Harry Howard Tulane University

ORGANIZACIÓN DEL CURSO Neurospan/ El curso es apto para un electivo en neurociencia. Neurolinguistics and linguistic aphasiology está en reserva en la biblioteca. Human Research Protection Program Before beginning research at Tulane University, all research personnel must complete the CITI Training Program; this can be completed at 02/21/11 2 SPAN Harry Howard - Tulane University

REPASO ¡La prueba es el repaso! 02/21/11 SPAN Harry Howard - Tulane University 3

UNA DISTINCIÓN Características como la sonoridad, el lugar y la manera de articulación pertenecen a fonos = segméntales. Características como el acento pertenecen a un grupo de fonos = suprasegméntales o prosódicas. La prosodia es el conjunto de inflexiones melódicas que hace la voz durante la producción de la cadena fónica. tono, intensidad (volumen), cantidad (duración) 02/21/11 10 SPAN Harry Howard - Tulane University

S UMMARY lexical stress CONvert ~ conVERT tone languages phrasal stress noun compounding stress retraction clausal stress contrastive stress emotional prosody sentence type declarative, interrogative, imperative LHRH 02/21/11 SPAN Harry Howard - Tulane University 5

MORE RECENT RESEARCH: LATERALIZATION OF ACOUSTIC CUES OR PARAMETERS Cue or parameter models seek hemispheric specialization in some component of the acoustic signal which either flags a semantic construct (a cue) or constitutes a broad physical measure (a parameter). I know of five well-articulated positions that have been set forth as the defining cue or parameter of hemispheric specialization: the acoustic transitions that make up a given phonological segment the duration of the transitions the frequency of the spectral information the frequency of information in general the size of temporal integration windows categorical vs. graded relations Normal speech confounds these hopelessly, so it will be quite a challenge to tease out and evaluate the contribution of any single one. 02/21/11 6 SPAN Harry Howard - Tulane University

LA LATERALIZACIÓN DEL SISTEMA FÓNICO 2 02/21/11 7 SPAN Harry Howard - Tulane University

1. ACOUSTIC TRANSITIONS: NOTE THE CONTRAST [B]~[P] 02/21/11 8 SPAN Harry Howard - Tulane University

2. SHORT VS. LONG DURATION OF TRANSITIONS Early research pointed to the importance of duration over transition. For instance, Kimura’s initial experiments with dichotic listening uncovered the fact that right-ear superiority is most evident with stimuli containing rapid changes in the acoustic spectrum – not only in normal speech, but also in nonsense syllables and in speech played backwards. Furthermore, while the right ear advantage is most marked with relatively brief stop consonants, the effect is minimal or disappears with vowels. Vowels are linguistic entities, but the time course over which the critical information is present is considerably longer than with consonants. 02/21/11 9 SPAN Harry Howard - Tulane University

3. TEMPORAL VS. SPECTRAL FEATURES Some researchers have taken this work in a slightly different direction by postulating a qualitative differentiation in the cues that two hemispheres are sensitive to: the LH has a higher resolution for temporal information, the RH has a higher resolution for spectral information. Zatorre & Belin (2001) used PET to examine the response of human auditory cortex to spectral and temporal variation. Volunteers listened to sequences derived from a stimulus consisting of two pure tones separated by one octave alternating with a noise. In one condition, spectral information remained constant while speed of alternation was doubled at each level. In the other, speed was kept constant while the number of tones sampled within the octave was doubled at each level. Results indicated that responses to the temporal features were weighted towards LH, while responses to the spectral features were weighted towards RH. 02/21/11 10 SPAN Harry Howard - Tulane University

4. HIGH- VS. LOW-FREQUENCY INFORMATION LH acts like a low-pass filter by ignoring the low frequencies of some stimulus to concentrate on the higher ones. RH acts like a high-pass filter by ignoring the high frequencies of some stimulus to concentrate on the lower ones. Duration becomes a measure of frequency in the temporal domain – a brief signal has a high temporal frequency; a prolonged signal has a lower temporal frequency and at least two other domains are recognized, the spectral and the spatial. 02/21/11 11 SPAN Harry Howard - Tulane University

SPATIAL FREQUENCY 02/21/11 12 SPAN Harry Howard - Tulane University

WHAT IS THIS? 02/21/11 13 SPAN Harry Howard - Tulane University

SALVADOR DALI “Gala Contemplating the Mediterranean Sea, which at 30 meters becomes the portrait of Abraham Lincoln (Homage to Rothko)”, /21/11 SPAN Harry Howard - Tulane University 14

"LINCOLN ILLUSION” HARMON & JULES (1973) Blurring acts as a low-pass filter, reducing the high masking frequencies 02/21/11SPAN Harry Howard - Tulane University 15

SPATIAL FREQUENCY: LHD ~ STIMULUS ~ RHD 02/21/11 16 SPAN Harry Howard - Tulane University

5. SIZE OF TEMPORAL INTEGRATION WINDOWS Primary auditory cortex builds high-fidelity representations of the signal and surrounding non-primary areas differentially ‘elaborate’ this signal by analyzing it on different time scales (Poeppel et al., 2008) LH (non-primary) temporal cortex houses neuronal ensembles with somewhat shorter integration constants (say, ms) and therefore LH cortical fields preferentially reflect [fast] temporal properties of acoustic signals RH (non-primary) temporal cortex houses neuronal ensembles a large proportion of which have longer ( ms) integration windows, and therefore are better suited to analyze [slower] spectral change 02/21/11 17 SPAN Harry Howard - Tulane University

MULTI-TIME RESOLUTION ANALYSIS 02/21/11 18 SPAN Harry Howard - Tulane University

FUNCTIONAL LATERALIZATION AS A CONSEQUENCE OF TEMPORAL INTEGRATION 02/21/11 19 SPAN Harry Howard - Tulane University intonation contours formant transitions Analysis requiring high spectral resolution Analysis requiring high temporal resolution LHRH

6. CATEGORICAL ~ GRADED OR COORDINATE DISTINCTIONS Others argue that it cannot be a simple specialization of the LH for temporal processing and the RH for spectral processing, especially fundamental frequency, because RHD patients are deficient in both. The alternative is that the LH encodes categorical distinctions the RH encodes graded or coordinate distinctions. By categorical, we mean those distinctions that are all or none, such as whether a word bears focal stress or not. By graded or coordinate, we mean those distinctions that can take on many values. Emotion is a natural choice for expression via a graded phenomenon, since one’s emotional arousal is itself a graded state. 02/21/11 20 SPAN Harry Howard - Tulane University

CATEGORICAL (ABOVE/BELOW) ~ GRADED OR COORDINATE (NEAR/FAR) RELATIONS 02/21/11 21 SPAN Harry Howard - Tulane University

S UMMARY OF LATERALIZATION OF PHONOLOGY LHRH lexical, phrasal, clausal stress; lexical tone in Thai/Chinese sentence type emotional intonation categorical distinctionsgraded/continuous distinctions rapid cues > small window of temporal integration slow cues > large window of temporal integration high frequency: formantslow frequency: fundamental time-dependent and sequential, i.e. temporal order, sequence, and duration of sounds and of intervals between sounds time-independent, i.e. pitch and harmonic structure (spectral) > inability to perceive frequency- related information [temporal cues][spectral cues] 02/21/11 22 SPAN Harry Howard - Tulane University

EL PRÓXIMO DÍA La lateralización C §18 02/21/11 23 SPAN Harry Howard - Tulane University