Head-anchored whole-cell recordings in freely moving rats

Intracellular recordings are routinely used to study the synaptic and intrinsic properties of neurons in vitro. A key requirement for these recordings is a mechanically very stable preparation; thus their use in vivo had been limited previously to head-restrained animals. We have recently demonstrated that anchoring the electrode rigidly in place with respect to the skull provides sufficient stabilization for long-lasting, high-quality whole-cell recordings in awake, freely moving rats. This protocol describes our procedure in detail, adds specific instructions for targeting hippocampal CA1 pyramidal neurons and updates it with changes that facilitate patching and improve the success rate. The changes involve combining a standard, nonhead-mounted micromanipulator with a gripper to firmly hold the recording pipette during the anchoring process then gently release it afterwards. The procedure from the beginning of surgery to the end of a recording takes ∼5 h. This technique allows new studies of the mechanisms underlying neuronal integration and cellular/synaptic plasticity in identified cells during natural behaviors.

[1]  Albert K. Lee,et al.  Whole-Cell Recordings in Freely Moving Rats , 2006, Neuron.

[2]  P. Maclean,et al.  Differential effects of septal and olfactory volleys on intracellular responses of hippocampal neurons in awake, sitting monkeys. , 1970, Journal of neurophysiology.

[3]  David S. Greenberg,et al.  Population imaging of ongoing neuronal activity in the visual cortex of awake rats , 2008, Nature Neuroscience.

[4]  C D Woody,et al.  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. , 1993, Journal of neurophysiology.

[5]  B. Sakmann,et al.  In vivo, low-resistance, whole-cell recordings from neurons in the anaesthetized and awake mammalian brain , 2002, Pflügers Archiv.

[6]  Winfried Denk,et al.  A Miniature Head-Mounted Neurotechnique Two-Photon Microscope: High-Resolution Brain Imaging in Freely Moving Animals , 2001 .

[7]  D. Tank,et al.  Imaging Large-Scale Neural Activity with Cellular Resolution in Awake, Mobile Mice , 2007, Neuron.

[8]  D. Hubel.  Single unit activity in striate cortex of unrestrained cats , 1959, The Journal of physiology.

[9]  M. Steriade,et al.  Natural waking and sleep states: a view from inside neocortical neurons. , 2001, Journal of neurophysiology.

[10]  Lucien T. Thompson,et al.  Long-term stability of the place-field activity of single units recorded from the dorsal hippocampus of freely behaving rats , 1990, Brain Research.

[11]  M. Fee,et al.  Active Stabilization of Electrodes for Intracellular Recording in Awake Behaving Animals , 2000, Neuron.

[12]  J. Kauer,et al.  Whole-Cell Patch-Clamp Recording Reveals Subthreshold Sound-Evoked Postsynaptic Currents in the Inferior Colliculus of Awake Bats , 1996, The Journal of Neuroscience.

[13]  J. O'Keefe,et al.  The hippocampus as a spatial map. Preliminary evidence from unit activity in the freely-moving rat. , 1971, Brain research.

[14]  B L McNaughton,et al.  Dynamics of the hippocampal ensemble code for space. , 1993, Science.

[15]  K. Horikawa,et al.  A versatile means of intracellular labeling: injection of biocytin and its detection with avidin conjugates , 1988, Journal of Neuroscience Methods.

[16]  C. Petersen,et al.  Correlating whisker behavior with membrane potential in barrel cortex of awake mice , 2006, Nature Neuroscience.