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Titolo:
Anatomical loops and their electrical dynamics in relation to whisking by rat
Autore:
Kleinfeld, D; Berg, RW; OConnor, SM;
Indirizzi:
Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA Univ Calif San Diego La Jolla CA USA 92093 t Phys, La Jolla, CA 92093 USA
Titolo Testata:
SOMATOSENSORY AND MOTOR RESEARCH
fascicolo: 2, volume: 16, anno: 1999,
pagine: 69 - 88
SICI:
0899-0220(1999)16:2<69:ALATED>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
VIBRISSAL MOTOR CORTEX; SPINAL TRIGEMINAL PROJECTIONS; STEM SUBNUCLEUS INTERPOLARIS; PRIMARY SOMATOSENSORY CORTEX; MEDIAL VENTRAL POSTERIOR; SOMATIC SENSORY CORTEX; SUPERIOR COLLICULUS; BRAIN-STEM; BARREL CORTEX; SOMATOTOPIC ORGANIZATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
143
Recensione:
Indirizzi per estratti:
Indirizzo: Kleinfeld, D Univ Calif San Diego, Dept Phys, 9500 Gilman Dr, La Jolla, CA92093 USA Univ Calif San Diego 9500 Gilman Dr La Jolla CA USA 92093 USA
Citazione:
D. Kleinfeld et al., "Anatomical loops and their electrical dynamics in relation to whisking by rat", SOMAT MOT R, 16(2), 1999, pp. 69-88

Abstract

An accumulation of anatomical, behavioral, and electrophysiological evidence allows us to identify the neuronal circuitry that is involved with vibrissa-mediated sensation and the control of rhythmic vibrissa movement. Anatomical evidence points to a multiplicity of closed sensorimotor loops, whileelectrophysiological data delineate the flow of electrical signals in these pathways. These loops process sensory input from the vibrissae and send projections to direct vibrissa movement, starting at the level of the hindbrain and proceeding toward loops that involve multiple structures in the forebrain. The nature of the vibrissa-related electrical signals in behaving animals has been studied extensively at the level of neocortical loops. Two types of spike signal are observed that serve as a reference of vibrissa motion: a fast signal that correlates with the relative phase of the vibrissae within a whisk cycle and a slow signal that correlates with the amplitude, and possibly the set-point, of the vibrissae during a whisk. Both signalsare observed in vibrissa primary sensory (SI) cortex, and in some cases they are sufficiently robust to allow vibrissa position to be accurately estimated from the spike train of a single neuron. Unlike the case for S1 cortex, only the slow signal has been observed in vibrissa primary motor (M1) cortex. The control capabilities of M1 cortex were estimated from experimentswith anesthetized animals in which progressive areas along the vibrissa motor branch were microstimulated with rhythmically applied currents. The motion of the vibrissae followed stimulation of M1 cortex only for rates that were well below the frequency of rhythmic whisking; in contrast, the vibrissae followed stimulation of the facial nucleus, whose cells directly drive the vibrissae, for rates above that of whisking. In toro, the evidence implies that there is fast signaling from the facial nucleus, through the mystacial pad and the vibrissae and up through sensory cortex, but only slow signaling at the level of the motor cortex and down through the superior colliculus to the facial nucleus. The transformation from fast sensory signals to slow motor control is an unresolved issue. On the other hand, there is a candidate scheme to understand how the fast reference of vibrissa motion inthe whisk cycle may be used to decode the angle of the vibrissae upon their contact with an object. We discuss a circuit in which servo mechanisms are used to determine the angle of contact relative to the preferred phase ofthe fast reference signals. Support for this scheme comes from results with anesthetized animals on the frequency and phase entrainment of intrinsic neuronal oscillators in S1 cortex. A prediction based on this scheme is that the output from a decoder circuit is maximal when the angle of contact differs from the preferred phase of a fast regerence signal. In contrast, forcorrelation-based schemes the output is maximal when the angle of contact equals the preferred phase.

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Documento generato il 03/04/20 alle ore 07:55:59