Content area
Full Text
B R I E F COM M U N I C AT I O N S
Neural dynamics of in vitro cortical networks reflects experienced temporal patterns
Hope A Johnson1, Anubhuthi Goel2 & Dean V Buonomano2
Learning ultimately relies on changes in the flow of activityin neural microcircuits. The plasticity of neural dynamics is particularly relevant for the processing of temporal information. Chronic stimulation of cultured rat cortical networks revealed experience-dependent plasticity in neural dynamics. We observed changes in the temporal structure of activity that reflected the intervals used during training, suggesting that cortical circuits are inherently capable of temporal processing on short timescales.
2010 Nature America, Inc. All rights reserved.
Timing and temporal processing in the range of tens and hundreds of milliseconds is critical for many forms of sensory and motor processing, but the neural mechanisms underlying the ability to discriminate or produce short intervals remain unknown1,2. Recent studies have lent support to the notion that timing is an inherent computational ability of cortical circuits and may be performed locally2. This view implies that the temporal structure of the internal dynamics of cortical networks should be shaped by the temporal patterns that the network experiences. To examine this issue, we studied the effects of
the presentation of simple spatiotemporal stimulus patterns on cortical neural dynamics using organotypic slices. As with in vivo cortical networks, evoked stimulation in organotypic networks can elicit complex polysynaptic responses that reflect local network dynamics. This preparation is therefore well suited to study the plasticity of neural dynamics.
External stimulation was presented to cortical cultures via two implanted bipolar stimulating electrodes3. We first examined whether the temporal pattern of stimulation produced any form of network plasticity, defined as changes in evoked patterns of activity. The implanted electrodes (E1 and E2) were activated with a burst of pulses presented in-phase (synchronously) or with a 100-ms interval (onset to onset), every 10 s for 2 h (see Fig. 1a and Supplementary Fig. 1). Given the large degree of variability in the presence and structure of polysynaptic activity in naive slices, all of the presented data is derived from paired experiments in which sister slices were trained with one of two protocols and compared4. After training in the incubator
a
b
Far...