Multielectrode Recordings in the Somatosensory System

摘要: A fundamental goal in systems neuroscience is to explain animal behavior terms of the dynamics neural ensembles. Multielectrode techniques greatly facilitate approach toward this goal. Aside from fact that each experiment provides a higher yield data as compared single-site recordings, some questions simply cannot be addressed using only one electrode at time. For example, multisite recordings can determine whether different neurons respond independently stimuli, or covary trial trial. The purpose chapter review methods used multielectrode studies rat somatosensory system, with an emphasis on whisker system. We present basic toolbox we have probe functions populations behavioral context. includes for applying controlled training tactile discrimination tasks, reversibly inactivating specific brain areas, and analysis ensemble data.These already revealed properties system would been difficult impossible uncover single-electrode recordings. cortical (Zhu Connors, 1999; Ghazanfar Nicolelis, 2001; Diamond et al., 1992; 2000; Schubert 2001) thalamic (Armstrong-James Fox, 1987; Nicolelis Chapin, 1994) large multiwhisker receptive fields are dynamic over poststimulus time (Nicolelis 1994; 2000). These data, together observations supralinear summation inputs (Ghazanfar 1997; Shimegi, 2000), suggest field function integrate time-varying 2001). multineuron response additional stimulus-coding S1 ensembles code stimulus location single-neuron temporal patterns relative latencies their neurons, but not single-trial covariations among 1998; In S2 primate, other hand, multiple did contribute significantly coding punctate Even S1, contribution coordinated firing may increase greater complexity, because stimuli lead prevalence synchronous responses between infragranular layers than (Zhang Alloway, 2005).Combining led further conclusion spatiotemporal RF arise intrinsic local neighbor connections, rather interactions levels recording presence absence feedback corticofugal projections contributed both short- long-latency components ventral posterior medial nucleus (VPM) (Krupa interlevel were reflected simultaneous trigeminal areas stem, thalamus, cortex, which widespread oscillatory synchronization 1995). correlated activity remains even after transection facial nerve, suggests such generated centrally. Although high coherence associated 7–12 Hz state suggested seizures number authors (Marescaux Shaw 2006; Shaw, 2007), direct test showed rats robustly mild stimulation during bouts oscillations contradicting interpretation (Wiest 2003). Thus, synchronized need preclude perception; fact, it enhance aspects sensory representation (Fontanini Katz, 2006) well long-term plasticity (Erchova Diamond, 2004).These demonstrations fast distributed across maps processing stages paralleled by tight coupling two hemispheres (Shuler Wiest 2005). This cross-talk challenges classical conception barrel cortex encoder exclusively contralateral potential importance bilateral whisker-guided discriminations (Krupa, 2001b; Shuler 2002).Multielectrode while performed feed-forward model signal 2004). rate modulations began before clearly could explained bottom-up propagation signal. Rather, must shaping task-related responses. Similarly, found vary spontaneously occurring states (Nelson, 1996; Fanselow Moore Fanselow, 2002; Castro-Alamancos, 2004; Moore, collectively widely coordinate activities millisecond scales, functional connectivity them quickly adjusted contexts.The preceding examples meant indicate range results achieved arrays (MEAs). following sections developed past 15 years. selected represent major phase typical study, design surgical implantation, through involving stimulation, monitoring, reversible inactivation recorded many-neuron data.