Locomotion in intact and in brain cortex-ablated cats

• Published in: Neuroscience Vol. 358; pp. 37 - 48
• Main Authors: López Ruiz, José Roberto, Castillo Hernández, Luis, De la Torre Valdovinos, Braniff, Franco Rodríguez, Nancy Elizabeth, Dueñas Jiménez, Judith Marcela, Dueñas Jiménez, Alejandro, Rivas-Carrillo, Jorge David, Dueñas Jiménez, Sergio Horacio
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.09.2017
• Subjects: Animals; Biomechanical Phenomena; Cats; Cerebral Cortex - physiology; cerebral cortex ablation; Cerebral Decortication; cutaneous reflexes; electromyograms; Electromyography; Evoked Potentials, Motor - physiology; kinematics; locomotion; Locomotion - physiology; Muscle, Skeletal - physiology; Reflex - physiology; Torso - innervation; electromyograms; kinematics; cutaneous reflexes; cerebral cortex ablation; locomotion
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2017.06.026

•The Brain Cortex Ablated Cat differs from other common decerebrations resulting in a specific set of locomotion changes.•Subcortical structures allow close to normal locomotion in brain cortex ablated cats.•Cortex ablation reduce most post stimulation cutaneous SURAL and SAPHENOUS reflexes.•Elicited cutaneous reflexes are speed dependent in the brain cortex ablated cat. The current decerebration procedures discard the role of the thalamus in the motor control and decortication only rules out the brain cortex part, leaving a gap between the brain cortex and the subthalamic motor regions. In here we define a new preparation denominated Brain Cortex-Ablated Cat (BCAC), in which the frontal and parietal brain cortices as well as the central white matter beneath them were removed, this decerebration process may be considered as suprathalamic, since the thalamus remained intact. To characterize this preparation cat hindlimb electromyograms (EMG), kinematics and cutaneous reflexes (CR) produced by electrical stimulation of sural (SU) or saphenous (SAPH) nerves were analyzed during locomotion in intact and in BCAC. In cortex-ablated cats compared to intact cats, the hindlimb EMG amplitude was increased in the flexors, whereas in most extensors the amplitude was decreased. Bifunctional muscle EMGs presented complex and speed-dependent amplitude changes. In intact cats CR produced an inhibition of extensors, as well as excitation and inhibition of flexors, and a complex pattern of withdrawal responses in bifunctional muscles. The same stimuli applied to BCAC produced no detectable responses, but in some cats cutaneous reflexes produced by electrical stimulation of saphenous nerve reappeared when the locomotion speed increased. In BCAC, EMG and kinematic changes, as well as the absence of CR, imply that for this cat preparation there is a partial compensation due to the subcortical locomotor apparatus generating close to normal locomotion.