To see whether connections between the spinal cord posterior to thoracic levels and supraspinal structures are required for lordosis, hormone-primed female rats were studied before and after complete transection of the spinal cord at low thoracic levels. All sham-operated rats showed strong lordosis reflexes before and after surgery. None of the rats receiving complete spinal transections performed lordosis after surgery, even in tests done 3 months and more after transection (Kow, Montgomery, and Pfaff, 1977). Even pharmacological attempts to facilitate lordosis failed to bring out the reflex in spinally transected hormone-primed female rats (Kow et al., 1980b). Thus, supraspinal control is required for the normal lordosis reflex. The net effect of this control must be facilitation of lordosis-relevant circuitry at segmental spinal levels.
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