Metamorphosis and Locomotionthe Frog, Rana Catesbeiana

V

X

XV

XX

XXI

XXII

XXIII

XVIII

Primary Motoneurons Secondary Motoneurons

Retrograde staining of motoneurons in the 9th ventral root usinghorseradish peroxidase (HRP) reveals two populations of motoneurons.

Primary motoneurons are born very early in embryonic development(during gastrulation) and innervate the swimming musculature of the tadpole.

Secondary motoneurons are born later, beginning in larval stages andcontinuing through metamorphosis.

Forehand, C.J. & Farel, P.B. (1982) Spinal cord development in anuran larvae: I. Primary and secondary motoneurons. J. Comp. Neurol., 209, 386-394.

Axons of primary motoneurons exit in medial fascicles (M) of the ventral roots.Axons of secondary motoneurons exit in lateral fascicles (L) of the ventral roots.

Stehouwer, D.J. & Farel, P.B. (1985) Development of locomotormechanisms in the frog. J. Neurophysiol., 53, 1453-1466.

Stehouwer, D.J. & Farel, P.B. (1985) Development of locomotormechanisms in the frog. J. Neurophysiol., 53, 1453-1466.

Stehouwer, D.J. & Farel, P.B. (1985) Development of locomotormechanisms in the frog. J. Neurophysiol., 53, 1453-1466.

Stehouwer, D.J. & Farel, P.B. (1985) Development of locomotor mechanisms in the frog. J. Neurophysiol., 53, 1453-1466.

Stehouwer, D.J. & Farel, P.B. (1985) Development of locomotormechanisms in the frog. J. Neurophysiol., 53, 1453-1466.

Stehouwer, D.J. & Farel, P.B. (1985) Development of locomotormechanisms in the frog. J. Neurophysiol., 53, 1453-1466.

V

X

XV

XX

XXI

XXII

XXIII

XVIII

Stehouwer, D.J. (1987) Metamorphosis of behavior in the bullfrog (Rana catesbeiana). Dev. Psychobiol., 21, 383-395.

1 2 3 4

Stehouwer, D.J. (1987) Metamorphosis of behavior in the bullfrog (Rana catesbeiana). Dev. Psychobiol., 21, 383-395.

V

X

XV

XX

XXI

XXII

XXIII

XVIII

Stehouwer & Farel, (1984) Development of hindlimb locomotorbehavior in the frog. Dev. Psychobiol., 17, 217-232.

Stehouwer, D.J. (1992) Development of anuran locomotion: Ethological and neurophysiological considerations. J. Neurobiol., 23, 1467-1485.

Stage XV Stage XVIII

Maturation of Pedal Locomotionin Rana Catesbeiana

1. Intrinsic mechanisms

2. Contextual stimuli

3. Morphological change

1. Intrinsic mechanismsIllustrated in isolated CNS preparations

•patterned input to motoneurons precedes muscle differentation•alternation between left and right sides is first activity observed•synchronous activity appears relatively late

Maturation of Pedal Locomotionin Rana Catesbeiana

1. Intrinsic mechanisms

2. Contextual stimuli•Change in habitat preference from deep water to land•Increased stimulation of the limbs and decreased effectiveness of tail

Maturation of Pedal Locomotionin Rana Catesbeiana

1. Intrinsic mechanisms

2. Contextual stimuli

3. Morphological change•Limbs become more effective and the tail becomes less effective due to changes in sizes

Maturation of Pedal Locomotionin Rana Catesbeiana

1. Intrinsic mechanisms

2. Contextual stimuli

3. Morphological change

Maturation of Pedal Locomotionin Rana Catesbeiana

Stehouwer, D.J. (1987) Compensatory eye movementsduring fictive swimming of a deafferented, reduced preparation in vitro. Brain Res., 410, 264-268.

Stehouwer, D.J. (1987) Compensatory eye movementsduring fictive swimming of a deafferented, reduced preparation in vitro. Brain Res., 410, 264-268.