On the Dynamics of Synaptic Inputs During Ongoing Activity in the Cortex
In this chapter, we provide an overview of the dynamical properties of spontaneous activity in the cortex, as represented by the subthreshold membrane potential fluctuations of the cortical neurons. First, we discuss the main findings from various intracellular recording studies performed in anesthetized animals as well as from a handful of studies in awake animals. Then, we focus on two specific questions pertaining to random and deterministic properties of cortical spontaneous activity. One of the questions is the relationship between excitation and inhibition, which is shown to posses a well-defined structure, owing to the spatio-temporal organization of the spontaneous activity in local cortical circuits at the millisecond scale. The other question regards the spontaneous activity at a scale of seconds and minutes. Here, examination of repeating patterns in subthreshold voltage fluctuations failed to reveal any evidence for deterministic structures.
KeywordsSpontaneous Activity Synaptic Input Intracellular Recording Surrogate Data Inhibitory Input
We would like to thank Profs. Carl Petersen, Igor Timofeev, and Tony Zador for providing examples of intracellular recordings in awake animals from experiments conducted in their laboratories (Fig. 1). We thank all the members of Lampl lab for their contribution to this work. This work was supported by grants from the Israel Science Foundation (1037/03, 326/07), the National Institute for Psychobiology in Israel, by the Henry S. and Anne Reich Research Fund for Mental Health, the Asher and Jeanette Alhadeff Research Award, and Sir Charles Clore fellowship.
- 1.Abeles M (1991) Corticonics. Cambridge: Cambridge University press.Google Scholar
- 2.Abeles M (2004) Neuroscience. Time is precious. Science 304:523–524.Google Scholar
- 6.Atallah BV, Scanziani M (2008) Proportional excitatory and inhibitory conductances are maintained during gamma oscillations. In: COSYNE. Salt Lake City, UT.Google Scholar
- 8.Baranyi A, Szente MB, Woody CD (1993) Electrophysiological characterization of different types of neurons recorded in vivo in the motor cortex of the cat. I. Patterns of firing activity and synaptic responses. J Neurophysiol 69:1850–1864.Google Scholar
- 27.Hromádka T (2007) Representation of Sounds in Auditory Cortex of Awake Rats, PhD thesis.Google Scholar
- 39.Okamoto H, Isomura Y, Takada M, Fukai T (2006) Combined Modeling and Extracellular Recording Studies of Up and Down Transitions of Neurons in Awake or Behaving Monkeys. In: The Basal Ganglia VIII, pp. 555–562.Google Scholar