Intracortical pathways mediate nonlinear fast oscillation (>200 Hz) interactions within rat barrel cortex.
Whisker evoked fast oscillations (FOs; >200 Hz) within the rodent posteromedial barrel subfield are thought to reflect very rapid integration of multiwhisker stimuli, yet the pathways mediating FO interactions remain unclear and may involve interactions within thalamus and/or cortex. In the present study using anesthetized rats, a cortical incision was made between sites representing the stimulated whiskers to determine how intracortical networks contributed to patterns of FOs. With cortex intact, simultaneous stimulation of a pair of whiskers aligned in a row evoked supralinear responses between sites separated by several millimeters. In contrast, stimulation of a nonadjacent pair of whiskers within an arc evoked FOs with no evidence for nonlinear interactions. However, stimulation of an adjacent pair of whiskers in an arc did evoke supralinear responses. After a cortical cut, supralinear interactions associated with FOs within a row were lost. These data indicate a distinct bias for stronger long-range connectivity that extends along barrel rows and that horizontal intracortical pathways exclusively mediate FO-related integration of tactile information.
Staba
Richard J
RJ
Department of Psychology, University of Colorado, UCB 345, Boulder, CO 80309-0345, USA. staba@psych.colorado.edu
Ard
Tyler D
TD
Benison
Alexander M
AM
Barth
Daniel S
DS
D000818:Animals; D001931:Brain Mapping; D003399:Craniotomy / Q000379:methods; D003576:Electron Transport Complex IV / Q000378:metabolism; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D008297:Male; D009434:Neural Pathways / Q000502:physiology*; D017711:Nonlinear Dynamics; D010812:Physical Stimulation / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000166:cytology / Q000502:physiology*; D014738:Vibrissae / Q000166:cytology / Q000502:physiology*
D003576:Electron Transport Complex IV