DTA

Digital Theses Archive

 

Tesi etd-10052017-114119

Type of thesis
Perfezionamento
Author
GENNA, CLARA
URN
etd-10052017-114119
Title
Cortical models of sensory processing during tactile stimulation in humans and animals
Scientific disciplinary sector
ING-IND/34
Course
INGEGNERIA - Biorobotics
Committee
relatore MICERA, SILVESTRO
Keywords
  • Bilateral Activation
  • Neural Decoding
  • Sensory Processing
  • SEPs
  • Somatosensory Cortex
  • Touch
Exam session start date
;
Availability
parziale
Abstract
The sense of touch is fundamental in performing common actions such as manipulation and recognition of objects. Afferent sensory signals are sent through the spinal cord up to the brain in the Somatosensory Cortex (SC). The SC represents and processes tactile information originating from the contralateral side of the body. However, recent studies have demonstrated that the SC receives inputs from the ipsilateral body side as well. The aim of this thesis is to investigate the bilateral integration of tactile information and thus how these sensory signals are represented in the neural network. The three studies comprising this thesis aimed at characterizing the cortical responses to tactile input in both humans and animals. Specifically, Study 1 and 2 provide a macroscale monitoring via electroencephalogram (EEG) during a prolonged unilateral stimulation of the human fingertip. In this way, the dynamics of cortical responses can be investigated in longer time-window by providing a model of brain activation throughout the stimulation (Study 1). Complementary, a sensory discrimination task was performed in Study 2 to investigate the modulation of the elicited sensory models by using tactile stimuli with different levels of roughness. Specifically, EEG features were extracted to quantify the brain activation and they were separated in two categories: stimulus-dependent (i.e., cortical factors modulated by the tactile roughness in both hemispheres) and stimulus-invariant, features related mostly to a basic sensory processing. Finally, Study 3 provides a microscale monitoring in rats via patch-clamp technique in order to investigate whether ipsilateral activation of single neuron encodes the delivered tactile input. Additionally, long-lasting after-effects in sensory processing were investigated by performing a decoding analysis in separate temporal window.The results of this thesis provide insight into the bilateral representation of touch by suggesting time-variant neurophysiological models of brain processes.
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