Auditory-visual interaction in single cells in the cortex of the superior temporal sulcus and the orbital frontal cortex of the macaque monkey

264

235

The brain should integrate related but not unrelated information from different senses. Temporal patterning of inputs to different modalities may provide critical information about whether those inputs are related or not. We studied effects of temporal correspondence between auditory and visual streams on human brain activity with functional magnetic resonance imaging (fMRI). Streams of visual flashes with irregularly jittered, arrhythmic timing could appear on right or left, with or without a stream of auditory tones that coincided perfectly when present (highly unlikely by chance), were noncoincident with vision (different erratic, arrhythmic pattern with same temporal statistics), or an auditory stream appeared alone. fMRI revealed blood oxygenation level-dependent (BOLD) increases in multisensory superior temporal sulcus (mSTS), contralateral to a visual stream when coincident with an auditory stream, and BOLD decreases for noncoincidence relative to unisensory baselines. Contralateral primary visual cortex and auditory cortex were also affected by audiovisual temporal correspondence or noncorrespondence, as confirmed in individuals. Connectivity analyses indicated enhanced influence from mSTS on primary sensory areas, rather than vice versa, during audiovisual correspondence. Temporal correspondence between auditory and visual streams affects a network of both multisensory (mSTS) and sensory-specific areas in humans, including even primary visual and auditory cortex, with stronger responses for corresponding and thus related audiovisual inputs.

Section: Activation Of Contralateral Human Msts By Audiovisual Tempormentioning

confidence: 58%

Section: Introductionmentioning

confidence: 96%

Audiovisual Temporal Correspondence Modulates Human Multisensory Superior Temporal Sulcus Plus Primary Sensory Cortices

Noesselt

Rieger²,

Schoenfeld³

et al. 2007

264

235

“…Such a convergence has been described in parietal area 7b (Hyvärinen, 1981;Graziano and Gross, 1995), in the ventral intraparietal area (VIP) (Colby et al, 1993;Duhamel et al, 1998;Bremmer et al, 2002;Schlack et al, 2002Schlack et al, , 2005, in the ventral premotor area (Rizzolatti et al, 1981;Graziano and Gross, 1995;Graziano et al, 1999;Graziano and Gandhi, 2000), in the superior temporal sulcus (Benevento et al, 1977;Leinonen et al, 1980;Bruce et al, 1981;Hikosaka et al, 1988), in the putamen (Graziano and Gross, 1995), and in the superior colliculus (SC) (Meredith and Stein, 1986a;Stein and Meredith, 1993;Wallace et al, 1996;Bell et al, 2001Bell et al, , 2003.…”

Section: Introductionmentioning

confidence: 95%

Multisensory Integration in the Ventral Intraparietal Area of the Macaque Monkey

Avillac¹,

Hamed²,

Duhamel³

2007

247

205

The goal of this study was to characterize multisensory interaction patterns in cortical ventral intraparietal area (VIP). We recorded single-unit activity in two alert monkeys during the presentation of visual (drifting gratings) and tactile (low-pressure air puffs) stimuli. One stimulus was always positioned inside the receptive field of the neuron. The other stimulus was defined so as to manipulate the spatial and temporal disparity between the two stimuli. More than 70% of VIP cells showed a significant modulation of their response by bimodal stimulations. These cells included both bimodal cells, i.e., cells responsive to both tested modalities, and seemingly unimodal cells, i.e., cells responding to only one of the two tested modalities. This latter observation suggests that postsynaptic latent mechanisms are involved in multisensory integration. In both cell categories, neuronal responses are either enhanced or depressed and reflect nonlinear sub-, super-, or additive mechanisms. The occurrence of these observations is maximum when stimuli are in temporal synchrony and spatially congruent. Interestingly, introducing spatial or temporal disparities between stimuli does not affect the sign or the magnitude of interactions but rather their occurrence. Multisensory stimulation also affects the neuronal response latencies of bimodal stimuli. For a given neuron, these are on average intermediate between the two unimodal response latencies, again suggesting latent postsynaptic mechanisms. In summary, we show that the majority of VIP neurons perform multisensory integration, following general rules (e.g., spatial congruency and temporal synchrony) that are closely similar to those described in other cortical and subcortical regions.

“…The superior temporal polysensory (STP) cortex, the homolog of the human STS, is a polymodal area in nonhuman primates (Benevento et al, 1977;Poremba et al, 2003). Because the STP cortex is connected to unimodal visual and auditory areas, as well as the amodal medial temporal lobe and prefrontal cortex (Blatt et al, 2003;Padberg et al, 2003), the human STS is well suited to the formation of both crossmodal and intramodal linkages.…”

Section: Sts For Binding Stimulimentioning

confidence: 99%

Functionally Segregated Neural Substrates for Arbitrary Audiovisual Paired-Association Learning

Tanabe¹,

Honda²,

Sadato³

2005

To clarify the neural substrates and their dynamics during crossmodal association learning, we conducted functional magnetic resonance imaging (MRI) during audiovisual paired-association learning of delayed matching-to-sample tasks. Thirty subjects were involved in the study; 15 performed an audiovisual paired-association learning task, and the remainder completed a control visuo-visual task. Each trial consisted of the successive presentation of a pair of stimuli. Subjects were asked to identify predefined audiovisual or visuo-visual pairs by trial and error. Feedback for each trial was given regardless of whether the response was correct or incorrect. During the delay period, several areas showed an increase in the MRI signal as learning proceeded: crossmodal activity increased in unimodal areas corresponding to visual or auditory areas, and polymodal responses increased in the occipitotemporal junction and parahippocampal gyrus. This pattern was not observed in the visuo-visual intramodal paired-association learning task, suggesting that crossmodal associations might be formed by binding unimodal sensory areas via polymodal regions. In both the audiovisual and visuo-visual tasks, the MRI signal in the superior temporal sulcus (STS) in response to the second stimulus and feedback peaked during the early phase of learning and then decreased, indicating that the STS might be key to the creation of paired associations, regardless of stimulus type. In contrast to the activity changes in the regions discussed above, there was constant activity in the frontoparietal circuit during the delay period in both tasks, implying that the neural substrates for the formation and storage of paired associates are distinct from working memory circuits.