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Orienting behaviour and superior colliculus sensory representations in mice with the vibrissae bent into the
1Dipartimento di Anatomia e Fisiologia Umana, Università di Torino, Italy.
Abstract:
When a tactile stimulus touches the body on one side, animals show an orienting response toward that side with the eyes, the head or the entire body. This movement requires the transformation of sensory information into motor commands. The superior colliculus is supposed to be a fundamental part of the brain where this sensorimotor transformation occurs and where one of the possible mechanisms could be the alignment among sensory and motor topographies. We changed the body shape of mice in order to analyse the development of new orienting responses following tactile stimulation. To do this, we bent the left vibrissae from left to right such that they were located in the right portion of the visual hemifield. If left-right inversion was performed in adults, tactile stimulation of the left vibrissae performed from the right produced wrong orienting movements to the left. Conversely, if left-right inversion was performed in newborns, mice learned to respond correctly to the right. By recording from superior colliculus multisensory neurons of mice whose vibrissae were displaced at birth, we found a shift of visual and auditory receptive fields from left to right in those multisensory neurons receiving tactile input from the displaced vibrissae. These results show the strict relation existing between the neuronal modifications in the superior colliculus and the changes in orienting behaviour. These findings also suggest two important conclusions. First, sensory mapping in the superior colliculus depends on sensory inputs coming from the same portion of space.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Mice learn to adjust their orienting responses to tactile stimuli by altering sensory maps in the superior colliculus. Early life sensory input shapes sensorimotor transformations for adaptive behavior.
Area of Science:
- Neuroscience
- Sensory processing
- Motor control
Background:
- Orienting responses to tactile stimuli involve sensorimotor transformation.
- The superior colliculus is a key brain region for this transformation, potentially through aligning sensory and motor maps.
Purpose of the Study:
- To investigate how altering body shape affects the development of orienting responses.
- To understand the role of the superior colliculus in adapting sensorimotor transformations.
Main Methods:
- Mice vibrissae were repositioned from left to right, altering tactile input location.
- Orienting behaviors were observed after tactile stimulation in adult and newborn mice with altered vibrissae.
- Multisensory neurons in the superior colliculus were recorded from mice with early-life vibrissae displacement.
Main Results:
- Adult mice with repositioned vibrissae showed incorrect orienting movements.
- Newborn mice with repositioned vibrissae learned correct orienting responses.
- Superior colliculus neurons showed shifts in visual and auditory receptive fields corresponding to the altered tactile input.
Conclusions:
- Neuronal plasticity in the superior colliculus is directly linked to changes in orienting behavior.
- Sensory maps within the superior colliculus are shaped by spatially congruent sensory inputs.
- Early-life sensory experience is crucial for developing adaptive sensorimotor transformations.