Neocortical interpretation of haptic and visual events across brain states: Electrophysiological investigations in sensory information processing
Author
Summary, in English
This thesis delves into the complex architecture of dynamic sensory information processing in the neocortex. Specifically, it asks how primary sensory cortical regions are influenced by local and widespread cortical state changes. Central to this question is the exploration of two historically opposing information processing frameworks emphasizing a local and global information processing principle respectively, i.e. the principle that certain areas of the brain are dedicated to specific functions and the principle that individual functions are distributed over a large network.
Results were obtained through in vivo extracellular recordings in anesthetized rats while high-resolution spatiotemporal visual, tactile, and visuo-tactile input patterns were provided. Paper I showed that color input evokes rapid local state changes in primary visual cortex (V1) which result in unique temporal response patterns among neurons recorded within the same vertical axis, thereby challenging the historically popular idea of columnar organization. Paper II used field potential recordings as estimates of changes in the widespread and local cortical state and showed a significant differential effect on individual neuronal responses to haptic input in the primary somatosensory cortex (S1). In paper III, spontaneous activity among S1 neuron populations was defined as a high-dimensional state space that was found to shift in different ways when providing tactile, visual, and visuo-tactile input, questioning the idea of unimodal cortical regions.
Together, the results suggest that both local and widespread internal brain states can impact processing of sensory information in primary sensory regions. It is concluded that the functional localization model cannot fully explain what we and other researchers have observed about cortical sensory information processing and that brain state dependence on the neuronal representation of sensory input is more likely a result of coordinated activity across multiple, interconnected brain regions.
Results were obtained through in vivo extracellular recordings in anesthetized rats while high-resolution spatiotemporal visual, tactile, and visuo-tactile input patterns were provided. Paper I showed that color input evokes rapid local state changes in primary visual cortex (V1) which result in unique temporal response patterns among neurons recorded within the same vertical axis, thereby challenging the historically popular idea of columnar organization. Paper II used field potential recordings as estimates of changes in the widespread and local cortical state and showed a significant differential effect on individual neuronal responses to haptic input in the primary somatosensory cortex (S1). In paper III, spontaneous activity among S1 neuron populations was defined as a high-dimensional state space that was found to shift in different ways when providing tactile, visual, and visuo-tactile input, questioning the idea of unimodal cortical regions.
Together, the results suggest that both local and widespread internal brain states can impact processing of sensory information in primary sensory regions. It is concluded that the functional localization model cannot fully explain what we and other researchers have observed about cortical sensory information processing and that brain state dependence on the neuronal representation of sensory input is more likely a result of coordinated activity across multiple, interconnected brain regions.
Department/s
Publishing year
2024
Language
English
Publication/Series
Lund University, Faculty of Medicine Doctoral Dissertation Series
Issue
2024:64
Full text
Document type
Dissertation
Publisher
Lund University, Faculty of Medicine
Topic
- Neurosciences
Keywords
- Haptics
- Visual
- Multisensory
- Cortical
- Rodent
- Neurophysiology
- Tactile
- Electrophysiology
Status
Published
Research group
- Neural Basis of Sensorimotor Control
Supervisor
ISBN/ISSN/Other
- ISSN: 1652-8220
- ISBN: 978-91-8021-557-2
Defence date
10 May 2024
Defence time
13:00
Defence place
Segerfalksalen, BMC A10, Sölvegatan 17 i Lund. Join by Zoom: https://lu-se.zoom.us/j/62438522869
Opponent
- Håkan Oalusson (Professor)