Response Properties of Corticotectal and Corticostriatal Neurons in the Posterior Lateral Suprasylvian Cortex of the Cat

Abstract

Lateral suprasylvian cortex (LS) is an important source of visual projections to both the striatum and superior colliculus. Although these two LS efferent systems are likely to be involved in different aspects of visual processing, little is known about their functional properties. In the present experiments, 86 neurons in halothane-anesthetized, paralyzed cats were recorded along the posterior aspects of the medial and lateral banks of LS (PMLS and PLLS). Neurons were selected for analysis on the basis of antidromic activation from electrodes chronically implanted in the superior colliculus and caudate nucleus. The segregated nature of corticostriatal and corticotectal neurons was apparent; in no instance could a neuron be antidromically activated from both the superior colliculus and the caudate nucleus. Many common features were revealed between corticotectal and corticostriatal neurons; the majority of neurons in both populations were binocular and contralaterally dominant, showed similar responses to stationary flashed light, and expressed within-field spatial summation and surround inhibition. However, a number of information-processing features distinguished between corticotectal and corticostriatal neurons; the former were generally tuned to lower velocities than were the latter, and, for a given eccentricity in visual space, corticotectal neurons had smaller receptive fields than did corticostriatal neurons. Moreover, most corticotectal neurons displayed a marked preference for movements toward temporal visual space, whereas corticostriatal neurons revealed no specialization for a particular direction of movement. In addition, whereas corticotectal neurons were selective for receding stimuli, corticostriatal neurons were selective for approaching stimuli. The presence of these two corticofugal pathways is discussed in relation to their presumptive functional roles in the facilitation of attentive and orientation behaviors.

NMDA-dependent facilitation of corticostriatal plasticity by the amygdala

“…However, this problem might be circumvented if the BLA effect required that multiple pairings with cortical inputs occurred over time before a significant potentiation is achieved. Although 60 such pairings were sufficient to induce LTP in our conditions, the minimum number of coincident cortical-BLA firings might be different in vivo where corticostriatal neurons exhibit sustained spontaneous activity (46,47). In these conditions, BLA inputs might only facilitate cortical synapses that consistently and repeatedly exhibit phasic increases in activity around BLA spikes.…”

Corticostriatal Activity in Primary Motor Cortex of the Macaque

“…Two recent studies in cats found only minor differences between CSNs and corticotectal neurons (Niida et al, 1997;Weyand and Gafka, 1998), and those differences indicated that CSNs were less selective for specific visual stimuli than neighboring corticotectal cells. The disparity with the present results may be explained by the different cortical areas sampled and accompanying differences in CSN type (Gerfen and Wilson, 1996) and/or species differences.…”

Vibrissa Sensation in Superior Colliculus: Wide-Field Sensitivity and State-Dependent Cortical Feedback

“…The jitter in the peak2 spikes may be caused by the fact that the peak2 EPSP rides on top of an IPSP. In cats, corticotectal inputs are very significant and have been extensively studied (Ogasawara et al, 1984; Norita et al, 1991; McHaffie et al, 1993; Niida et al, 1997). For example, inactivating the cortex affects the responses of superior colliculus cells to visual stimulation (McHaffie et al, 1993) and supralinear integration of responses from different sensory modalities in the superior colliculus is dependent on corticotectal pathways (Wallace and Stein, 1994; Wilkinson et al, 1996; Jiang et al, 2001).…”