Excitatory responses in the ?direct? striatonigral pathway: Effect of nigrostriatal lesion

Ultrafast Dynamics of o‐Bromofluorobenzene Studied by Time‐Resolved Photoelectron Imaging

“…About 60% of DMN cells showed a short‐latency response to striatal stimulation (Fig. 8), a percentage similar to that reported for SNR cells (Rodríguez et al, 2000). In accordance with this, stained fibers and terminals were observed in the DMN after BDA injection in the striatum, although the density of striatal afferents was lower in the DMN than in the SNR.…”

“…DMN GABA‐containing cells showed a chemical profile very similar to that of SN GABA‐containing cells (Reiner and Anderson, 1993; Rajakumar et al, 1994), and particularly for those of the lateral SN and the caudomedial region of the SNR (GAD65+, GAD67+, PV+, CB−, nNOS−; González‐Hernández and Rodríguez, 2000). Despite the fact that some DMN cells showed fast bursts (2–4 msec between successive spikes) that were never found in SNR cells, most DMN neurons displayed biphasic spikes (first peak positive or negative) and a conduction velocity similar to that observed in the SNR (Guyenet and Aghajanian, 1978; Rodríguez and González‐Hernández, 1999; Rodríguez et al, 2000; see also Figs. 1 and 2).…”

“…It has been recently reported that, along with GABAergic inhibitory fibers, the striatonigral pathway contains excitatory projections (White et al, 1994; Rodríguez et al, 2000) that probably release dynorphin (Vincent et al, 1982; Christensson‐Nylander et al, 1986), substance P (Brownstein et al, 1977; Gale et al, 1977; Kanawaza et al, 1977), or neurokinin A (Lee et al, 1986; Lindefors et al, 1986). In the DMN, we observed an excitatory response to striatal stimulation similar to that found in the SNR (Rodríguez et al, 2000), suggesting the existence of an excitatory component in the striato‐DMN projection. We thus suggest that the striato‐DMN projection is composed of two different components, an inhibitory one that probably releases GABA, and another, excitatory, one whose chemical nature, although unknown, could be similar to that proposed for the striatonigral excitatory pathway.…”

“…We thus suggest that the striato‐DMN projection is composed of two different components, an inhibitory one that probably releases GABA, and another, excitatory, one whose chemical nature, although unknown, could be similar to that proposed for the striatonigral excitatory pathway. However, the possible striatal stimulation of a glutamatergic cortico‐mesencephalic projection cannot be completely ruled out (Rodríguez et al, 2000), and caution should be used until morphological evidence for a striato‐DMN excitatory projection can be provided.…”

Processing of dynamic visual information in the caudate nucleus

“…The dorsolateral aspect of the caudate body in the cat can receive its visual afferentation from the tectum via the suprageniculate nucleus of the thalamus (Harting, et al, 2001;Nagy, et al, 2003;Rokszin, et al, 2011) Recently, a direct projection from the visual association cortex to the caudate nucleus in the feline brain has also been described (Nagy, et al, 2011). The visual inputs of the substantia nigra may originate from the caudate nucleus (Rodríguez, et al, 2000) and from direct (Comoli, et al, 2003) or indirect tectal pathways through the subthalamic nucleus (Kita & Kitai, 1987;Tokuno, et al, 1994;Jiang, et al, 2003) and the pedunculopontine tegmental nucleus (Redgrave, et al, 1987;Lokwan, et al, 1999). The sensory and multisensory receptive field organization of single neurons that we found in these two structures may lend further support to the concept of a tectal, extrageniculate pathway conveying multisensory information to the caudate nucleus and the substantia nigra pars reticulata (Nagy, et al, 2005a;Nagy, et al, 2006).…”