Eye Position Affects Activity in Primary Auditory Cortex of Primates

Werner-Reiss, Uri; Kelly, Kristin N.; Trause, Amanda S.; Underhill, Abigail M.; Groh, Jennifer M.

doi:10.1016/s0960-9822(03)00168-4

Cited by 181 publications

(165 citation statements)

References 53 publications

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“…One or more tungsten electrodes were inserted just above the dura for the scan; these electrodes were readily visible in the images and served as reference points for the reconstruction of the recording locations. In accordance with the boundaries of the core auditory cortex identified in the literature (for details, see Werner-Reiss et al, 2003), we limited our recording locations to those Ն5 mm rostral from the caudal end of the supratemporal plane, Ն2 mm from the medial end of the supratemporal plane in the region caudal to the insula/circular sulcus, and Ն2 mm from the lateral edge of the supratemporal plane. In the region adjacent to the insula/circular sulcus, recording locations were restricted to those within the supratemporal plane rather than dipping down onto the lower/outer bank of the circular sulcus.…”

Section: Methodsmentioning

confidence: 99%

“…The reason for this design is that changes in eye position can produce changes in activity in auditory cortical neurons (Werner-Reiss et al, 2003;Fu et al, 2004;Woods et al, 2006). At the same time, visual stimuli can themselves influence the responses of auditory cortical neurons (Ghazanfar et al, 2005) as well as neurons in other areas of the auditory pathway (Porter et al, 2007).…”

Section: Does the Visual Fixation Stimulus Affect Auditory Spatial Sementioning

confidence: 99%

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A Rate Code for Sound Azimuth in Monkey Auditory Cortex: Implications for Human Neuroimaging Studies

Werner-Reiss

2008

J. Neurosci.

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Is sound location represented in the auditory cortex of humans and monkeys? Human neuroimaging experiments have had only mixed success at demonstrating sound location sensitivity in primary auditory cortex. This is in apparent conflict with studies in monkeys and other animals, in which single-unit recording studies have found stronger evidence for spatial sensitivity. Does this apparent discrepancy reflect a difference between humans and animals, or does it reflect differences in the sensitivity of the methods used for assessing the representation of sound location? The sensitivity of imaging methods such as functional magnetic resonance imaging depends on the following two key aspects of the underlying neuronal population: (1) what kind of spatial sensitivity individual neurons exhibit and (2) whether neurons with similar response preferences are clustered within the brain.To address this question, we conducted a single-unit recording study in monkeys. We investigated the nature of spatial sensitivity in individual auditory cortical neurons to determine whether they have receptive fields (place code) or monotonic (rate code) sensitivity to sound azimuth. Second, we tested how strongly the population of neurons favors contralateral locations. We report here that the majority of neurons show predominantly monotonic azimuthal sensitivity, forming a rate code for sound azimuth, but that at the population level the degree of contralaterality is modest. This suggests that the weakness of the evidence for spatial sensitivity in human neuroimaging studies of auditory cortex may be attributable to limited lateralization at the population level, despite what may be considerable spatial sensitivity in individual neurons.

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Section: Methodsmentioning

confidence: 99%

Section: Does the Visual Fixation Stimulus Affect Auditory Spatial Sementioning

confidence: 99%

A Rate Code for Sound Azimuth in Monkey Auditory Cortex: Implications for Human Neuroimaging Studies

Werner-Reiss

2008

J. Neurosci.

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“…In congruent AV speech, subadditive interactions in polysensory regions have also been observed (32). Additionally, anatomical evidence shows that primary sensory areas are directly interconnected (33)(34)(35)(36)(37)(38). Intersensory corticocortical connectivity may mediate cross-modal plasticity when one sensory system is compromised (39), but the role for nonimpaired systems remains unknown.…”

Section: Neurophysiological Basis Of Multisensory Integrationmentioning

confidence: 99%

Visual speech speeds up the neural processing of auditory speech

Wassenhove

Grant

Poeppel

2005

Proc. Natl. Acad. Sci. U.S.A.

749

115

831

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Synchronous presentation of stimuli to the auditory and visual systems can modify the formation of a percept in either modality. For example, perception of auditory speech is improved when the speaker's facial articulatory movements are visible. Neural convergence onto multisensory sites exhibiting supra-additivity has been proposed as the principal mechanism for integration. Recent findings, however, have suggested that putative sensory-specific cortices are responsive to inputs presented through a different modality. Consequently, when and where audiovisual representations emerge remain unsettled. In combined psychophysical and electroencephalography experiments we show that visual speech speeds up the cortical processing of auditory signals early (within 100 ms of signal onset). The auditory-visual interaction is reflected as an articulator-specific temporal facilitation (as well as a nonspecific amplitude reduction). The latency facilitation systematically depends on the degree to which the visual signal predicts possible auditory targets. The observed auditory-visual data support the view that there exist abstract internal representations that constrain the analysis of subsequent speech inputs. This is evidence for the existence of an ''analysis-by-synthesis'' mechanism in auditory-visual speech perception. combinations'' such as ''pk '' or ''kp '' but never a fused percept. These results illustrate the effect of input modality on the perceptual AV speech outcome and suggest that multisensory percept formation is systematically based on the informational content of the inputs. In classic speech theories, however, visual speech has seldom been accounted for as a natural source of speech input. Ultimately, when in the processing stream (i.e., at which representational stage) sensory-specific information fuses to yield unified percepts is fundamental for any theoretical, computational, and neuroscientific accounts of speech perception.Recent investigations of AV speech are based on hemodynamic studies that cannot speak directly to timing issues (2, 3). Electroencephalographic (EEG) and magnetoencephalographic (4-7) studies testing AV speech integration have typically used oddball or mismatch negativity paradigms, thus the earliest AV speech interactions have been reported for the 150-to 250-ms mismatch response. Whether systematic AV speech interactions can be documented earlier is controversial, although nonspeech effects can be observed early (8). AV Speech as a Multisensory ProblemSeveral properties of speech are relevant to the present study. (i) Because AV speech is ecologically valid for humans (9, 10), one might predict an involvement of specialized neural computations capable of handling the spectrotemporal complexity of AV speech (compared to, say, arbitrary tone-flash pairings), for which no natural functional relevance can be assumed. (ii) Natural AV speech is characterized by particular dynamics such as (a) the temporal precedence of visual speech (the movement of the facial articulators typically ...

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“…Factors other than attention can also influence activity of single neurons in the primary auditory cortex: various behavioral contingencies (Beaton and Miller, 1975;Miller et al, 1972), eye position (Fu et al, 2004;Werner-Reiss et al, 2003), and somatosensory stimulation (Brosch et al, 2005;Fu et al, 2003;Lakatos et al, 2007;Schroeder et al, 2001). …”

Section: Beyond Sound In Auditory Cortexmentioning

confidence: 99%

“…However, even some of the early studies suggested that neural activity in early stages of auditory processing might be influenced by nonauditory factors; such as "attention" influencing "electric activity" in the cochlear nucleus (Hernandez-Peon et al, 1956), and "attention units" in auditory cortex (Hubel et al, 1959). Since then, multiple studies supported the idea of multisensory, or behavioral interactions in auditory cortex, whether they were using evoked potentials (Giard and Peronnet, 1999;Oatman, 1971Oatman, , 1976Picton et al, 1971), field potentials (Ghazanfar et al, 2005), magnetoencefalography (Gobbelé et al, 2003;Lütkenhöner et al, 2002), or fMRI (Calvert et al, 1997;Foxe et al, 2002;Johnson and Zatorre, 2005;Kayser et al, 2005;Petkov et al, 2004) Even at the level of single neurons in the primary auditory area, neuronal responses can be influenced by behavioral contingencies (Beaton and Miller, 1975;Miller et al, 1972), selective attention Miller et al, 1980), eye position (Fu et al, 2004;Werner-Reiss et al, 2003), or somatosensory stimulation (Brosch et al, 2005;Fu et al, 2003;Lakatos et al, 2007;Schroeder et al, 2001). The "top-down" (attention, behavioral contingencies), and "bottom-up" (somatosensory, eye movements) influences can be seen as enhancing auditory responses, and auditory processing (Lakatos et al, 2007;Schroeder and Foxe, 2005).…”

Section: Nonauditory Modulation Of Activity In Auditory Cortexmentioning

confidence: 99%