In vivo, low-resistance, whole-cell recordings from neurons in the anaesthetized and awake mammalian brain

Abstract

A blind patch-clamp technique for in vivo whole-cell recordings in the intact brain is described. Recordings were obtained from various neuronal cell types located 100-5,000 microm from the cortical surface. Access resistance of recordings was as low as 10 M Omega but increased with recording depth and animal age. Recordings were remarkably stable and it was therefore possible to obtain whole-cell recordings in awake, head-fixed animals. The whole-cell configuration permitted rapid dialysis of cells with a calcium buffer. In most neurons very little ongoing action potential (AP) activity was observed and the spontaneous firing rates were up to 50-fold less than what has been reported by extracellular unit recordings. AP firing in the brain might therefore be far sparser than previously thought.

Functional organization of excitatory synaptic strength in primary visual cortex

“…Recordings were made using the blind whole-cell patch technique 36 . Neurons were targeted at a depth of 150-300 μm below the pial surface (estimated using the reading of the micromanipulator).…”

Patch pipettes are more useful than initially thought: simultaneous pre- and postsynaptic recording from mammalian CNS synapses in vitro and in vivo

“…The representation of a whisker deflection in L2/3 is sparse. Unbiased recording in vivo from individual cells in the upper layer of cortex [25] indicates that the response is low (<1 AP/stimulus, [8]), and trial-totrial variability of AP responses is high with a coefficient of variation (C.V.) of >1 (de Kock et al, submitted). The local axonal projections of the recipient L2/3 cells are mostly in the tangential direction, and they supposedly integrate sensory signals from several whiskers.…”

“…Plasticity of synaptic efficacy in CNS synapses Unbiased recording from cortical neurons in vivo [25] indicates Fig. 7 In vivo unitary postsynaptic potential in the thalamocortical pathway.…”

Sensory experience modifies spontaneous state dynamics in a large-scale barrel cortical model

“…The weights of the synapses, in combination with the synaptic release, were adjusted to produce firing rates similar to those recorded in vivo (Zhu & Connors 1999, Margrie et al 2002, Armstrong-James & Fox 1987 as well as maintaining the stability of the spontaneous activity of the network. The initial excitatory weights were allowed to evolve with time (governed by the STDP rules described above) until the dynamics had equilibrated, i.e., the initial transient of the dynamics had died off (see Figure 2A).…”