Effects of paired-pulse and repetitive stimulation on neurons in the rat medial geniculate body

被引:59
作者
Bartlett, EL
Smith, PH [1 ]
机构
[1] Univ Wisconsin, Dept Anat, Madison, WI 53706 USA
[2] Johns Hopkins Univ, Dept Biomed Engn, Baltimore, MD 21205 USA
关键词
inferior colliculus; thalamus; corticothalamic; thalamocortical;
D O I
10.1016/S0306-4522(02)00240-3
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Many behaviorally relevant sounds, including language, are composed of brief, rapid, repetitive acoustic features. Recent studies suggest that abnormalities in producing and understanding spoken language are correlated with abnormal neural responsiveness to such auditory stimuli at higher auditory levels [Tallal et al., Science 271 (1996) 81-84; Wright et al., Nature 387 (1997) 176-178; Nagarajan et al., Proc. Natl. Acad. Sci. USA 96 (1999) 6483-6488] and with abnormal anatomical features in the auditory thalamus [Galaburda et al., Proc. Natl. Acad. Sci. USA 91 (1994) 8010-8013]. To begin to understand potential mechanisms for normal and abnormal transfer of sensory information to the cortex, we recorded the intracellular responses of medial geniculate body thalamocortical neurons in a rat brain slice preparation. Inferior colliculus or corticothalamic axons were excited by pairs or trains of electrical stimuli. Neurons receiving only excitatory collicular input had tufted dendritic morphology and displayed strong paired-pulse depression of their large, short-latency excitatory postsynaptic potentials. In contrast, geniculate neurons receiving excitatory and inhibitory collicular inputs could have stellate or tufted morphology and displayed much weaker depression or even paired-pulse facilitation of their smaller, longer-latency excitatory postsynaptic potentials. Depression was not blocked by ionotropic glutamate, GABA(A) or GABA(B) receptor antagonists. Facilitation was unaffected by GABAA receptor antagonists but was diminished by N-methyl-D-aspartate (NMDA) receptor blockade. Similar stimulation of the corticothalamic input always elicited paired-pulse facilitation. The NMDA-independent facilitation of the second cortical excitatory postsynaptic potential lasted longer and was more pronounced than that seen for the excitatory collicular inputs. Paired-pulse stimulation of isolated collicular inhibitory postsynaptic potentials generated little change in the second GABAA potential amplitude measured from the resting potential, but the GABAB amplitude was sensitive to the interstimulus interval. Train stimuli applied to collicular or cortical inputs generated intra-train responses that were often predicted by their paired-pulse behavior. Long-lasting responses following train stimulation of the collicular inputs were uncommon. In contrast, corticothalamic inputs often generated long-lasting depolarizing responses that were dependent on activation of a metabotropic glutamate receptor. Our results demonstrate that during repetitive afferent firing there are input-specific mechanisms controlling synaptic strength and membrane potential over short and long time scales, Furthermore, they suggest that there may be two classes of excitatory collicular input to medial geniculate neurons and a single class of small-terminal corticothalamic inputs, each of which has distinct features. (C) 2002 IBRO. Published by Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:957 / 974
页数:18
相关论文
共 83 条
[1]   INTRACELLULAR STUDIES IN THE FACIAL NUCLEUS ILLUSTRATING A SIMPLE NEW METHOD FOR OBTAINING VIABLE MOTONEURONS IN ADULT-RAT BRAIN-SLICES [J].
AGHAJANIAN, GK ;
RASMUSSEN, K .
SYNAPSE, 1989, 3 (04) :331-338
[2]  
AITKIN LM, 1969, EXP BRAIN RES, V7, P68
[3]   MORPHOLOGY AND SPATIAL-DISTRIBUTION OF CORTICOTHALAMIC TERMINALS ORIGINATING FROM THE CAT AUDITORY-CORTEX [J].
BAJO, VM ;
ROUILLER, EM ;
WELKER, E ;
CLARKE, S ;
VILLA, AEP ;
DERIBAUPIERRE, Y ;
DERIBAUPIERRE, F .
HEARING RESEARCH, 1995, 83 (1-2) :161-174
[4]  
Bartlett E. L., 1999, Society for Neuroscience Abstracts, V25, P1665
[5]  
Bartlett Ed, 1995, Society for Neuroscience Abstracts, V21, P1175
[6]   Anatomic, intrinsic, and synaptic properties of dorsal and ventral division neurons in rat medial geniculate body [J].
Bartlett, EL ;
Smith, PH .
JOURNAL OF NEUROPHYSIOLOGY, 1999, 81 (05) :1999-2016
[7]   Comparison of the fine structure of cortical and collicular terminals in the rat medial geniculate body [J].
Bartlett, EL ;
Stark, JM ;
Guillery, RW ;
Smith, PH .
NEUROSCIENCE, 2000, 100 (04) :811-828
[8]  
BARTLETT EL, 1997, ASS RES OTOLARYNGOL, V20, P190
[9]   RESPONSE PROPERTIES OF SINGLE UNITS IN AREAS OF RAT AUDITORY THALAMUS THAT PROJECT TO THE AMYGDALA .1. ACOUSTIC DISCHARGE PATTERNS AND FREQUENCY RECEPTIVE-FIELDS [J].
BORDI, F ;
LEDOUX, JE .
EXPERIMENTAL BRAIN RESEARCH, 1994, 98 (02) :261-274
[10]   Pre- and postsynaptic whole-cell recordings in the medial nucleus of the trapezoid body of the rat [J].
Borst, JGG ;
Helmchen, F ;
Sakmann, B .
JOURNAL OF PHYSIOLOGY-LONDON, 1995, 489 (03) :825-840