A staggering diversity of animals face a similar task: how to process sensory input, through multiple levels of the nervous system, to control movement? When an animal moves, this movement stimulates its own sensory receptors, providing feedback used in the control of subsequent movement. In active sensing, animals alter the patterns of sensory feedback by changing the patterns of their movements for the purpose of sensing. For example, you move your hand in distinct and deliberate ways to sense an objects weight, shape, texture, or temperature. Such active movements for sensing are found across animal species and the neural underpinnings of active sensing remain a mystery. 


Intellectual Merit

'Active sensing' is the process by which animals (including humans) expend energy to alter the sensory feedback they receive to achieve behavioral goals. A challenge of studying active sensing is that it occurs in 'closed-loop': ongoing sensory feedback is used to alter subsequent movements, that in turn shape sensory feedback.  For example, when you hunt for the bathroom light switch at night, you are using the same set of muscles for two ends: gathering information (i.e. "feeling" your way around) as well as achieving your motor goal ("lights on"). 

This work addresses this challenge by examining the consequences of opening and closing this feedback loop in a well-suited animal model, weakly electric fish. This remarkable creature allows for investigating the interplay between sensory information and motor programs for active sensing. Indeed, a key discovery enabled by this project was that active sensing movements in weakly electric fish are under continuous feedback control, as reported in Biswas et al,2019, which appeared in Current Biology.  The graphical image included shows a bottom view of an electric fish as it swims forward and backward to active probe its environment. In this unique experimental manipulation, the movement of the refuge was linked to the movement of the fish, creating an augmented sensory experience. The researchers showed that despite this manipulation, the fish modulated its own output so that the error signal remained constant. 

The findings from this project have been published in a wide variety of venues including open-access journals such as eLife and Scientific Reports. The results published from this work are relevant to a broad range of tasks, sensory modalities, and motor systems found across animal species including humans.

Broader Impacts

Through this work we have trained a wide range of graduate and undergraduate students, including several from groups traditionally underrepresented in STEM fields. This training has included hands-on research experiences, training in multidisciplinary science and engineering approaches to biology, presentation of work to international scientific audiences at major science meetings, and co-authorship of papers in top journals. 

Last Modified: 06/03/2020
Modified by: Noah J Cowan