Scanned optogenetic control of mammalian somatosensory input to map input-specific behavioral outputs

Somatosensory stimuli guide and shape behavior, from immediate protective reflexes to longer-term learning and higher-order processes related to pain and touch. However, somatosensory inputs are challenging to control in awake mammals due to the diversity and nature of contact stimuli. Application of cutaneous stimuli is currently limited to relatively imprecise methods as well as subjective behavioral measures. The strategy we present here overcomes these difficulties, achieving 'remote touch' with spatiotemporally precise and dynamic optogenetic stimulation by projecting light to a small defined area of skin. We mapped behavioral responses in freely behaving mice with specific nociceptor and low-threshold mechanoreceptor inputs. In nociceptors, sparse recruitment of single action potentials shapes rapid protective pain-related behaviors, including coordinated head orientation and body repositioning that depend on the initial body pose. In contrast, activation of low-threshold mechanoreceptors elicited slow-onset behaviors and more subtle whole-body behaviors. The strategy can be used to define specific behavioral repertoires, examine the timing and nature of reflexes, and dissect sensory, motor, cognitive and motivational processes guiding behavior.

The Effect of Co-Verbal Remote Touch on Electrodermal Activity and Emotional Response in Dyadic Discourse

This article explores the affective impact of remote touch when used in conjunction with video telecon. Committed couples were recruited to engage in semi-structured discussions after they watched a video clip that contained emotionally charged moments. They used paired touch input and output devices to send upper-arm squeezes to each other in real-time. Users were not told how to use the devices and were free to define the purpose of their use. We examined how remote touch was used and its impact on skin conductance and affective response. We observed 65 different touch intents, which were classified into broader categories. We employed a series of analyses within a framework of behavioral and experiential timescales. Our findings revealed that remote touches created a change in the overall psychological affective experience and skin conductance response. Only remote touches that were judged to be affective elicited significant changes in EDA measurements. Our study demonstrates the affective power of remote touch in video telecommunication, and that off-the-shelf wearable EDA sensing devices can detect such affective impacts. Our findings pave the way for new species of technologies with real-time feedback support for a range of communicative and special needs such as isolation, stress, and anxiety.

Cretaceous origins of the vibrotactile bill-tip organ in birds

Some probe-foraging birds locate their buried prey by detecting mechanical vibrations in the substrate using a specialized tactile bill-tip organ comprising mechanoreceptors embedded in densely clustered pits in the bone at the tip of their beak. This remarkable sensory modality is known as ‘remote touch’, and the associated bill-tip organ is found in probe-foraging taxa belonging to both the palaeognathous (in kiwi) and neognathous (in ibises and shorebirds) clades of modern birds. Intriguingly, a structurally similar bill-tip organ is also present in the beaks of extant, non-probing palaeognathous birds (e.g. emu and ostriches) that do not use remote touch. By comparison with our comprehensive sample representing all orders of extant modern birds (Neornithes), we provide evidence that the lithornithids (the most basal known palaeognathous birds which evolved in the Cretaceous period) had the ability to use remote touch. This finding suggests that the occurrence of the vestigial bony bill-tip organ in all modern non-probing palaeognathous birds represents a plesiomorphic condition. Furthermore, our results show that remote-touch probe foraging evolved very early among the Neornithes and it may even have predated the palaeognathous–neognathous divergence. We postulate that the tactile bony bill-tip organ in Neornithes may have originated from other snout tactile specializations of their non-avian theropod ancestors.