In the context of sensory processing, integration is defined as the process by which multiple senses are combined to create an unified perceptual experience that reflects the characteristics of each source of information (Stern & Wallace, 1986; Kastner et al., 2014). Sensory integration theory posits that multisensory inputs can be integrated by using either temporal or spatial correlation mechanisms. Temporal integration occurs when stimuli from different modalities arrive within a limited time frame such that they can no longer be distinguished individually, while spatial integration involves integrating input from separate locations into a coherent representation. In recent years, researchers have increasingly focused on investigating how these processes occur in the somatosensory system. Somatosensation refers to the sensory perception of physical stimulation arising from touch, temperature, pain, pressure, vibration, proprioception and tactile discrimination, among others. It plays a crucial role in our daily lives, allowing us to interact with objects and navigate through space.
Despite its importance, little is known about how the brain integrates multi-regional somatosensory inputs during tasks involving the body's movement or interactions with other people. This article will explore the predictive value of cortical oscillatory patterns in successful integration of multi-regional somatosensory input.
Cortical oscillations refer to rhythmic fluctuations in the electrical activity of neurons in the cerebral cortex. They are thought to play a key role in processing and transmitting sensory information across various regions of the brain (Goldman et al., 2002). Several studies suggest that certain types of cortical oscillations may be predictive of the degree of integration between multiple somatosensory regions.
Buzsáki et al. (1983) found that gamma (40-100 Hz) oscillations were more prominent when participants were asked to integrate touch and sound cues than when they processed them separately. Similarly, Rainer et al. (2006) reported that gamma oscillations increased during a task requiring participants to integrate visual and tactile information. These findings suggest that gamma oscillations may serve as a common currency for integrating different modalities of sensory information.
Research has shown that gamma oscillations can also predict the success of multisensory integration. In a study by Chang et al. (2012), participants performed a tactile-visual paired association learning task while their electroencephalogram (EEG) was recorded. The authors found that the strength of gamma oscillations correlated with the degree of successful integration between the two modalities, such that higher gamma power predicted better performance on the task. This finding is supported by other research indicating that synchrony between gamma oscillations in distinct cortical areas is critical for successful integration of multi-regional inputs (Kreiman et al., 20008; Kreiman et al., 2009).
This article explored how certain cortical oscillatory patterns are predictive of successful integration of multi-regional somatosensory input. Specifically, it discussed evidence suggesting that gamma oscillations may play a key role in facilitating such integration. Future research should aim to investigate the specific mechanisms underlying this phenomenon and identify other types of oscillatory patterns that may be similarly predictive.
Understanding these processes could lead to new insights into how the brain processes sensory information and integrates various sources of stimulation during complex behaviors such as movement and interaction with others.
Which cortical oscillatory patterns are predictive of successful integration of multi-regional somatosensory input?
The researchers found that synchronization between different brain regions was more evident during tactile stimulation than other types of sensory stimuli such as auditory or visual stimulation. Specifically, they measured the phase locking value (PLV) of theta, alpha, beta, gamma, and delta waves generated by EEG recordings during tactile stimulation and compared it with PLV values recorded during other forms of sensation.