Rhythm and Rate: Perception and Physiology HST November 2007 Jennifer Melcher

Forward suppression of unit activity in auditory cortex Brosch and Schreiner (1997) J Neurophysiol 77:

Brosch and Scheich (Epub ahead) Exp Brain Res. Forward facilitation of unit activity in auditory cortex

Forward suppression of auditory evoked cortical potentials Butler (2002) J Neurophysiol 88:

Brain Activity Increase Metabolic Response Blood Flow Increase Blood Oxygenation Increase Image Signal Increase Blood Oxygenation Level-Dependent fMRI

Percent Signal Change Time (seconds) Sound On Time Course of fMRI Activation: An Example

Cochlear Nucleus Inferior Colliculus Medial Geniculate Body Superior Olivary Complex Auditory Cortex 7 Human Auditory Pathway Auditory Cortex Cochlear Nucleus Medial Geniculate Body Inferior Colliculus Superior Olivary Complex Diagram of human auditory pathway from cochlea to cortex. Montage of images showing sound-evoked fMRI activation in the auditory pathway. fMRI activation (color scale) is superimposed on anatomical images (grayscale) intersecting different parts of the pathway.

Stimuli OffOn (30 s) time Noise Burst Stimulation paradigm for following slide.

Harms and Melcher (2002) J Neurophysiol 88: Different Dependencies on Sound Repetition Rate in Midbrain and Cortex Figure 3: Activation maps for the IC (two subjects, Exp. I). Stimuli were noise burst trains with repetition rates of 2, 10, or 35/s. Each panel shows a T1-weighted anatomic image (grayscale) and superimposed activation map (color) for a particular subject. Rectangle superimposed on the diagrammatic image (bottom, right) indicates the area shown in each panel. For the activation maps, regions are colored according to the result of a t-test comparison of image signal strength during “train on” and “off” periods. In this and all subsequent figures, blue and yellow correspond to the lowest (p = 0.01) and highest (p = 2 x ) significance levels, respectively. (Areas with p > 0.01 are not colored). Activation maps (based on functional images with an in-plane resolution of 3.1 x 3.1 mm) have been interpolated to the resolution of the anatomic images (1.6 x 1.6 mm). Images are displayed in radiological convention, so the subject's right is displayed on the left. R, right; L, left. Figure 7: Activation maps for HG and STG (two subjects, Exp. I). Stimuli were noise burst trains with repetition rates of 1, 2, 10, or 35/s. See Figure 3 caption.

Time (seconds) 35/s10/s 2/s Percent Signal Change Inferior Colliculus Auditory Cortex Sound On Harms and Melcher (2002) J Neurophysiol 88: Different Dependencies on Sound Repetition Rate in Midbrain and Cortex

0300 Time (seconds) Percent Signal Change (Normalized) Continuous Noise 35/s Clicks100/s Clicks Running Speech Music /s Noise Bursts /s Noise Bursts 030 2/s Noise Bursts A Wide Range of Activation Waveshapes in Auditory Cortex sustained phasic Sound On

Increasing Modulation Rate Increasing Sound Time Fraction Time (seconds) sustainedphasic 0 1 Percent Signal Change Time (seconds) Harms et al. (2005) J Neurophysiol 93: Sensitivity of Activation Waveshape to Sound Temporal Envelope Characteristics

Waveshape vs Level 35/s noise bursts Waveshape vs Rate 70 dB SL Percent Signal Change Time (s) dB SL 55 dB SL 40 dB SL Time (s) 2/s 35/s 0 2 Harms et al. (2005) J Neurophysiol 93: Insensitivity of Activation Waveshape to Sound Level

fMRI response waveshape in auditory cortex is sensitive to sound temporal envelope characteristics. insensitive to sound level and bandwidth.

Harms and Melcher (2002) J Neurophysiol 88:

Responses in a waking patient to repetitive binaural clicks at various rates. In sections A and B are responses to clicks at low rates, similar to those evoked by single clicks. Sections C, D and E show for higher stimulation rates the sequence: on-response, driving response, and off-response. In section F the driving response has practically disappeared, while the on-response and off- response persist unchanged. The estimated location of the responding electrode is indicated as number 1 in figure 1. Chatrian et al. (1960) Electroenceph. Clin. Neurophysiol. 12:

Many Successive Sounds Heard Time (seconds) sustainedphasic 0 1 Percent Signal Change Time (seconds) One Sound Heard The waveshape of cortical activation may also reflect perceptual aspects of a sound. The beginning and end of auditory objects may be delimited by distinct peaks in population neural activity of auditory cortex.

Harms and Melcher (2002) J Neurophysiol 88:

0 1 Percent Signal Change Time (seconds) Forward Suppression Neural Off Response Underlying Neurophysiology

Medial Geniculate Body 0 1 Auditory Cortex 0 1 Inferior Colliculus 0 1 Normalized Percent Change Activation Waveshape Across Levels of the Auditory Pathway Cochlear Nucleus Time (s) Superior Olivary Complex 0 1

Human Auditory Cortex: Spatial Variations in Activation Waveshape more sustained more phasic Heschl’s Gyrus lateral posterior Planum Temporale 030 Time (s) Normalized Percent Change 0 1

Frequency Time A B AA B A … … “1 stream” “gallop” From HST 723 lecture of Christophe Micheyl, Spring 2006.

Frequency Time A B AA B A … … ff

Frequency Time A B AA B A … … “2 streams!” “one high and slow, the other low and fast” …

Frequency Time A B AA B A … … …

Neuromagnetic Responses from Human Auditory Cortex Gutschalk et al. (2005) J. Neurosci. 25:

Neuromagnetic Responses from Human Auditory Cortex For Stimulus Producing a Bistable Percept Gutschalk et al. (2005) J. Neurosci. 25:

Figure 1: Stylized AEP in humans. The illustration is modeled after responses to brief stimuli recorded between two electrodes: at the vertex or top of the head and near the stimulated ear (inset at top right). Stimulus presentation is at 0 msec (at arrow in top waveform). Bottom: Entire AEP is shown: ABR (green), MLR (red), and LLR (blue). Top: The ABR has been expanded so its individual components can be resolved. The dashed trace indicates how the response to the same stimulus would differ if presented as the deviant stimulus in an oddball paradigm. The dashed waveform, minus the solid, is the MMN. "Mismatch Negativity" - or MMN - occurs in response to ”deviant" stimuli in oddball paradigm - can occur even when the subject is not attending to the stimuli - dependent on stimulus modality (e.g. auditory vs. visual) time standard stimulusdeviant stimulus Oddball Paradigm: Mismatch Negativity: Dependent on Stimulus Context Melcher (in press) Auditory Evoked Potentials. In: New Encyclopedia of Neuroscience. Ed. L. Squires. Elsevier.

Tuesday November 27: (1) Wehr & Zador (2005) Synaptic mechanisms of forward suppression in rat auditory cortex. Neuron 47: (2) Tubau et al. (2007) Individual differences in sequence learning and auditory pattern sensitivity as revealed with evoked potentials. Eur J Neurosci. 26: (3) Becker & Rasmussen (2007) The rhythm aftereffect: support for time sensitive neurons with broad overlapping tuning curves. Brain and Cognition 64: (4) 1 discussion question, to be answered by all, but with one person designated discussion leader Thursday November 29: (5) Wilson et al. (2007) Cortical fMRI activation to sequences of tones alternating in frequency: relationship to perceived rate and streaming. J Neurophysiol. 97: (6) Micheyl et al. (2005) Perceptual organization of tone sequences in the auditory cortex of awake macaques. Neuron 48: (7) 2 discussion questions Plan for discussion sessions for “Neuroimaging Correlates of Auditory Behavior”