In vivo whole-cell patch-clamp recording of sensory synaptic responses of cingulate pyramidal neurons to noxious mechanical stimuli in adult mice
© Koga et al; licensee BioMed Central Ltd. 2010
Received: 8 September 2010
Accepted: 28 September 2010
Published: 28 September 2010
The anterior cingulate cortex (ACC) plays important roles in emotion, learning, memory and persistent pain. Our previous in vitro studies have demonstrated that pyramidal neurons in layer II/III of the adult mouse ACC can be characterized into three types: regular spiking (RS), intermediate (IM) and intrinsic bursting (IB) cells, according to their action potential (AP) firing patterns. However, no in vivo information is available for the intrinsic properties and sensory responses of ACC neurons of adult mice. Here, we performed in vivo whole-cell patch-clamp recordings from pyramidal neurons in adult mice ACC under urethane anesthetized conditions. First, we classified the intrinsic properties and analyzed their slow oscillations. The population ratios of RS, IM and IB cells were 10, 62 and 28%, respectively. The mean spontaneous APs frequency of IB cells was significantly greater than those of RS and IM cells, while the slow oscillations were similar among ACC neurons. Peripheral noxious pinch stimuli induced evoked spike responses in all three types of ACC neurons. Interestingly, IB cells showed significantly greater firing frequencies than RS and IM cells. In contrast, non-noxious brush did not induce any significant response. Our studies provide the first in vivo characterization of ACC neurons in adult mice, and demonstrate that ACC neurons are indeed nociceptive. These findings support the critical roles of ACC in nociception, from mice to humans.
Recent reports from animals and human imaging studies demonstrate that the anterior cingulate cortex (ACC) plays important roles in many major physiological functions as well as pathological conditions [1–8]. A number of human brain imaging studies have shown that ACC activity is involved in different types of pain-related information processing [9–14]. To understand the basic cellular and molecular mechanisms of the ACC, in vitro electrophysiological studies of ACC cortical slices and the use of genetically manipulated mice have provided critical information about excitatory transmission and long-term plastic changes after peripheral tissue or nerve injuries [7, 8, 15–21]. These findings from normal and transgenic/knockout mice are in good accord with in vivo electrophysiological studies in rats and rabbits [5, 22]. However, fewer studies of nociceptive responses from ACC neurons have been reported from whole adult mice due to the technical limitations involved in in vivo electrophysiological recordings. Considering the increases of in vitro studies and the use of transgenic and gene knockout mice for the molecular study of ACC functions, it is necessary to study the intrinsic properties of ACC neurons under whole mouse preparations. Of particular interest is how the ACC is activated by in vivo sensory stimulation. To our knowledge, there has been no report of in vivo intrinsic electrophysiological properties of ACC neurons.
Here we report for the first time in vivo whole-cell patch-clamp recordings from the ACC of adult mice. Our unique in vivo whole-cell patch-clamp approach has the following major technical advantages: (1) the analyses of membrane potentials and synaptic currents of spontaneous excitatory postsynaptic currents (sEPSCs); (2) recording of evoked synaptic responses (EPSCs) induced by different types of peripheral sensory stimuli, (3) a long stable recording (up to 2 hrs) and (4) anatomic labeling of recorded neurons. We found that many ACC neurons are nociceptive, and show selective responses to peripheral noxious mechanical stimuli. Furthermore, ACC neurons showed bilateral responses to noxious (pinch) stimuli applied to both ipsilateral and contralateral hind paws.
In vivo recording from layer II/III pyramidal neurons of ACC
Neuronal firing patterns and slow oscillations
Summary of basic electrophysiological parameters of ACC layer II/III pyramidal neurons in adult mice in vivo
RS cells (n = 5)
IM cells (n = 31)
IB cells (n = 14)
-68.4 ± 2.2
-72.0 ± 1.9
-67.1 ± 2.3
Spontaneous AP threshold (mV)
-46.1 ± 2.9
-48.3 ± 1.4
-44.2 ± 2.0
Oscillation Frequency (Hz)
0.4 ± 0.08
0.41 ± 0.04
0.48 ± 0.04
Spike Height (mV)
56.1 ± 7.5
59.0 ± 2.3
57.5 ± 3.2
Spike Half Width (ms)
1.40 ± 0.23
1.40 ± 0.08
1.37 ± 0.09
fAHP Amplitude (mV)
-7.1 ± 1.4
-7.1 ± 2.2
Time of fAHP (ms)
2.2 ± 0.1
2.1 ± 0.2
sAHP Amplitude (mV)
-10.5 ± 2.0
-10.3 ± 0.8
-9.2 ± 1.6
Time of sAHP (ms)
65.8 ± 11.4
68.5 ± 9.4
59.8 ± 8.3
9.7 ± 1.3 a
13.1 ± 3.3 a, b
Pinch-evoked responses higher than 200%
In this study, we used urethane for animal's anesthesia in vivo. Urethane anesthesia is known to affect membrane potentials and produce slow oscillations which have up- and down-states [24–26]. To confirm that the classifications of firing patterns were not affected by different depths of urethane anesthesia, we next analyzed slow oscillations in individual types of cells. Although space clamp errors under voltage clamp conditions should be taken into consideration, the recording conditions under in vivo patch-clamp allow us to directly analyze the synaptic currents. Similar direct analyses have been successfully implemented in the spinal cord [27, 28] and primary somatosensory cortex . The voltage clamp recordings revealed inward slow oscillations of membrane currents at the holding membrane potential (VH) of -70 mV (Fig. 2C upper). The mean frequency of the oscillations was 0.42 ± 0.02 Hz, ranging from 0.05 to 0.75 Hz (n = 50) and were similar as in other cortical area [24, 25]. The spontaneous oscillation frequencies of individual types were similar in RS (0.40 ± 0.08 Hz), IM (0.41 ± 0.04 Hz) and IB cells (0.48 ± 0.04 Hz) (Fig. 2C bottom).
Spontaneous APs in response to innocuous brush in all cell types
Although it is known that innocuous stimuli does not significantly activate neurons in the ACC [5, 8], to our knowledge there is no systematic study that has examined innocuous stimulation evoked responses in individual cell types in the superficial layers of the ACC. Therefore, we first applied innocuous brush stimuli to the left hind paw. As expected, the brushing did not produce any evoked depolarizations with an AP at the onset of the stimuli in all cell types under urethane anesthesia (RS; 94.7 ± 10.5%, IM; 104.3 ± 4.1% and IB; 110.1 ± 8.0% vs control) (Fig. 3, 4B).
Noxious pinch evoked responses
The present study is the first to perform in vivo patch-clamp recordings from ACC neurons of adult mice under urethane anesthesia and to systematically characterize the action potential (AP) properties of layer II/III pyramidal neurons. From single labeled neuron morphological analyses, we confirmed recording positions. We chose to record from layer II/III neurons in the ACC because (1) our previous work mostly focused on synaptic transmission and plasticity of ACC layer II/III [18, 20, 21]; (2) most neurons located in layer II/III are pyramidal neurons; and (3) neurons in layer II/III receive robust sensory input. We found that three major electrophysiological classes of pyramidal neurons could be distinguished according to their firing patterns and the shapes of their APs: RS, IM and IB neurons. Finally, we applied cutaneous noxious pinch and innocuous brush stimuli to the ispilateral and/or contralateral hind paws whilst recording from each type of neuron. We revealed that the pinch-evoked responses in IB cells had significantly higher frequencies than those in RS and IM, although brush stimuli did not activate any cell type. In contrast, there were no significant differences between ispilateral and contralateral evoked-responses across all cell types.
Based on AP shape and specific discharge patterns, our current study recorded from three identified types of pyramidal neurons within the ACC, which composed 10, 62 and 28% of our recordings respectively. In contrast, using the same classification protocols, our previous in vitro spike study  demonstrated different population distributions for ACC RS, IM and IB pyramidal neurons in layer II/III of adult mice (25, 44 and 31%, respectively). In comparison with the in vitro study, IM neurons were more frequently observed (62% in vivo vs. 44% in vitro). On the other hand, the number of RS neurons observed under in vivo conditions (10%) was lower than under in vitro conditions (25%) although the percentage of IB (28%) neurons observed in our in vivo study was similar to those observed in vitro (31%). The population ratios of RS and IM cells under in vivo and in vitro conditions were significantly different (P < 0.01, χ2 test). One key conclusion from these studies is that in vitro brain slice preparations is useful for studying the spike properties of different types of ACC pyramidal cells in vivo.
It is important to note that some of the variations in the population ratios between in vivo and in vitro observations may be related to recording conditions including (i) anesthetic effects and (ii) variations in recording temperatures. The generation and shape of action potentials depend on sodium (Na), potassium (K) and calcium (Ca) channels [29, 30]. The main criteria distinguishing IM cells from RS cell is the presence of the afterdepolarization (ADP), which is generally composed of Na, T- and R-type Ca currents . Compared with in vitro conditions, in vivo states are more likely to maintain neurons in a healthy condition, and thus these channels may be more active than under in vitro conditions. In addition, it has been reported that urethane can affect various channels, including Na channels [31–33]. Although there were no differences in slow oscillation frequencies produced by urethane in the three types of cells (Fig. 2C), we cannot eliminate the effects of anesthesia on firing pattern classifications. Furthermore, our previous in vitro study  was conducted at room temperature, whereas the present study used recording temperatures ranging from 36-37°C. These differences in temperature may affect channel gating, which could explain a difference in ADP amplitude and hence the proportion of cells that are RS vs IM.
Spontaneous and evoked responses
We observed that the spontaneous APs frequencies in IB neurons were significantly higher than those in RS and IM neurons (Fig. 4A). It has been reported that the generation of AP bursting discharges are mainly dependent on Na and K channel activity [29, 30]. In fact, by raising extracellular K concentrations, or through potentiation of the persistent Na current with the Na channel toxin ATX II, a subset of cortical pyramidal neurons can be induced to switch from repetitive single spiking to a burst firing mode . Additionally, the blocking of M-current, which is a voltage-gated potassium current (current through Kv7 channels) and a low-threshold non-inactivating potassium current, neuronal firing can be switched from tonic discharge to an intermittent firing mode in the entorhinal cortex  and hippocampus . Therefore, it is possible that individual types of pyramidal neurons in the ACC may have different expressions of AP related channels.
We also found that IB neurons responded significantly more to noxious pinch stimuli (333%) than RS (185%) and IM cells (185%) (Fig. 6B). A possible explanation for this may be, in addition to differences in their intrinsic properties, that they exhibit differences in sensory input and anatomical features of individual types. It has been reported that IB and RS neurons in the neocortex have different characteristics in excitatory and inhibitory input [36–38]. IB neurons mainly receive excitatory input and rarely receive GABAergic inhibitory input . Furthermore, they receive smaller and slower rises and decays of GABAergic inputs than RS cells [36, 37]. Anatomically, IB neurons have larger cell bodies and longer, thicker apical dendrites than those in RS cells [36–38]. The functional implications of their intrinsic electrophysiological properties, their responses to various sensory stimuli and their morphological features need to be further investigated.
Neurons in layer II/III of the ACC receive sensory information from the medial thalamus, and in turn project to layer V neurons [7, 8, 39–41]. Layer V neurons in turn form synapses with various cortical areas including the amygdala, a structure critical for emotional fear and anxiety, and also the motor cortex, where they can generate motor responses such as emotional vocalizations or trigger aversive behaviors [4, 42, 43]. Taking into considerations of the different intrinsic physiological properties and pinch-evoked responses obtained in this study, it is possible that different classes of pyramidal neurons within the ACC contribute in different ways to the information processing that takes place in the ACC. In fact, when noxious stimuli was applied, RS and IM cells displayed phasic firing at the onset of the stimuli, whereas IB cells displayed a tonic firing pattern, acting like powerful amplifiers during stimulation (Fig. 5B). Additionally, noxious pinch stimuli induced increases in evoked AP frequency greater than 200% of control in 50% of IB neurons (Fig. 6A). Therefore, the generation of high-frequency burst discharges in IB neurons may strongly influence the responses of postsynaptic neurons and the operation of local cortical networks, and also may play important roles in various emotional and motor responses.
Our current spike study is the first in vivo study in ACC neurons of adult mice, and provides basic information of the intrinsic properties and noxious responses of pyramidal ACC neurons. In conjunction with acute pain and neuropathic pain models, in vivo patch clamp recordings would be a powerful technique. Considering the cumulative reports of studies using transgenic and gene knockout mice, the current study provides important information of the intrinsic properties for ACC neurons. The in vivo whole-cell patch-clamp method will allow us to reveal novel molecular and synaptic integrative mechanisms for synaptic transmission and plasticity within the ACC in the future.
Adult male C57BL/6 mice (8-12 weeks old) were used in this study. Anesthesia was induced with urethane (1.5 g/kg, i.p.) as described previously . Rectal temperature was kept at 36-37°C by means of a heating pad placed beneath the animal. The head of the mouse was fixed with a stereotaxic apparatus, and the skull was drilled to make a hole on the right parietal hemisphere (0-0.7 mm lateral to the midline, and 1.0 mm anterior to bregma) . The dura was partially removed and a plastic well with 5 mm height was fixed around the hole with an adhesive bond. The surface of the ACC was perfused with 95% O2-5% CO2 equilibrated Krebs solution at 37°C (mM: NaCl 124, KCl 2.5, CaCl2 2.0, MgSO4 2.0, NaH2PO4 1.0, NaHCO3 25, and glucose 10, pH 7.4, 300-310 mOsm). If mice moved, a 1/4 supplemental dose of urethane was provided. The reflex was also monitored. All experiments were performed under protocols approved by the University of Toronto Animal Care Committee.
In vivo Whole-cell patch-clamp recording
Blind whole-cell patch-clamp recordings were made from ACC neurons. The recordings were obtained with a patch electrode filled with a solution (mM: K-gluconate 120, KCl 5, CaCl2 0.5, MgCl2 1, EGTA 0.2, HEPES 10, and Mg-ATP 2, Na3-GTP 0.1 and phosphocreatine disodium 10 adjusted to pH 7.2 with KOH). Biocytin (0.2%) was included in the pipette solution to label recorded neurons. The electrode, with a resistance of 2-5 MΩ, was advanced at an angle of 65 degrees towards the midline, into the range of the ACC (from 0.15-0.4 mm lateral to midline, and from 0.2-0.8 mm anterior to bregma, and 0.2-0.5 mm ventral from surface of the brain) . After making a giga Ohm seal (the resistance of at least 5 GΩ), the membrane patch was ruptured by a brief period of negative pressure, thus resulting in the whole cell configuration. Access resistance < 50 MΩ was considered acceptable. Data were discarded if access resistance changed more than 15% during an experiment. Data were filtered at 2 kHz, and digitized at 10 kHz. A 10 mV liquid junction potential was subtracted from all membrane potentials.
Innocuous (paint brush) and noxious pinch (toothed forceps) stimuli were applied for 3-5 seconds to the skin of the left (ipsilateral) and/or right (contrarateral) hind paws. All stimuli were usually applied at intervals of at least 3 min.
Histology and confocal microscopy
After electrophysiological recordings, mice were deeply anesthetized with supplemental urethane, and perfused transcardially with 4% paraformaldehyde in 0.01 mM phosphate-buffered saline (PBS, pH 7.4). The cortex was removed and immersed overnight in the same fixative at 4°C, and rinsed in 0.01 mM PBS and sectioned transversely into 80 μm-thick slices using a Cryostat. The biocytin filled cells were rendered fluorescent by incubating overnight in a Cy3-conjugated streptavidin (Jackson ImmunoResearch Labs; West Grove, PA) solution (1 mg/ml of PBS) at 4°C. The following day, slices were equilibrated in 1% Tris buffered saline and mounted on glass slides. Labeled neurons were imaged by a confocal microscope (Fluoview FV 1000, Olympus, Tokyo, Japan).
Data are expressed as the mean ± SEM. Statistical significance was determined as P < 0.05 using the Student t-test, the Mann-Whitney U-test, the analysis of variance (ANOVA) or chi-square (χ2) test, and indicated by asterisks.
List of abbreviations
anterior cingulate cortex
regular spiking neurons
intrinsic bursting neurons
resting membrane potential
action potential voltage threshold
Supported by grants from the Canadian Institutes of Health Research (CIHR81086), the EJLB-CIHR Michael Smith Chair in Neurosciences and Mental Health, the Canada Research Chair and the WCU program to M. Z.
- Frankland PW, Bontempi B, Talton LE, Kaczmarek L, Silva AJ: The involvement of the anterior cingulate cortex in remote contextual fear memory. Science 2004, 304: 881–883. 10.1126/science.1094804PubMedView Article
- Frankland PW, O'Brien C, Ohno M, Kirkwood A, Silva AJ: Alpha-CaMKII-dependent plasticity in the cortex is required for permanent memory. Nature 2001, 411: 309–313. 10.1038/35077089PubMedView Article
- Johansen JP, Fields HL, Manning BH: The affective component of pain in rodents: direct evidence for a contribution of the anterior cingulate cortex. Proc Natl Acad Sci USA 2001, 98: 8077–8082. 10.1073/pnas.141218998PubMed CentralPubMedView Article
- Johansen JP, Fields HL, Manning BH: Glutamatergic activation of anterior cingulate cortex produces an aversive teaching signal. Nat Neurosci 2004, 7: 398–403. 10.1038/nn1207PubMedView Article
- Vogt BA: Pain and emotion interactions in subregions of the cingulate gyrus. Nat Rev Neurosci 2005, 6: 533–544. 10.1038/nrn1704PubMed CentralPubMedView Article
- Wei F, Xu ZC, Qu Z, Milbrandt J, Zhuo M: Role of EGR1 in hippocampal synaptic enhancement induced by tetanic stimulation and amputation. J Cell Biol 2000, 149: 1325–1334. 10.1083/jcb.149.7.1325PubMed CentralPubMedView Article
- Zhuo M: Neuronal mechanism for neuropathic pain. Mol Pain 2007, 3: 14. 10.1186/1744-8069-3-14PubMed CentralPubMedView Article
- Zhuo M: Cortical excitation and chronic pain. Trends Neurosci 2008, 31: 199–207. 10.1016/j.tins.2008.01.003PubMedView Article
- Tracy I, Mantyh PW: The cerebral signature for pain perception and its modulation. Neuron 2007, 55: 377–391. 10.1016/j.neuron.2007.07.012View Article
- Eisenberger NI, Lieberman MD, Williams KD: Does rejection hurt? An FMRI study of social exclusion. Science 2003, 302: 290–292. 10.1126/science.1089134PubMedView Article
- Apkarian AV, Bushnell MC, Treede RD, Zubieta JK: Human brain mechanisms of pain perception and regulation in health and disease. Euro J Pain 2005, 9: 463–484. 10.1016/j.ejpain.2004.11.001View Article
- Davis KD, Pope GE, Crawley AP, Mikulis DJ: Neural correlates of prickle sensation: a percept-related fMRI study. Nat Neurosci 2002, 5: 1121–1122. 10.1038/nn955PubMedView Article
- Singer T, Seymour B, O'Doherty J, Kaube H, Dolan RJ, Frith CD: Empathy for pain involves the affective but not sensory components of pain. Science 2004, 303: 1157–1162. 10.1126/science.1093535PubMedView Article
- Wager TD, Rilling JK, Smith EE, Sokolik A, Casey KL, Davidson RJ, Kosslyn SM, Rose RM, Cohen JD: Placebo-induced changes in FMRI in the anticipation and experience of pain. Science 2004, 303: 1162–1167. 10.1126/science.1093065PubMedView Article
- Wei F, Xia XM, Tang J, Ao H, Ko S, Liauw J, Qiu CS, Zhuo M: Calmodulin regulates synaptic plasticity in the anterior cingulate cortex and behavioral responses: A microelectroporation study in adult rodents. J Neurosci 2003, 23: 8402–8409.PubMed
- Cao XY, Xu H, Wu LJ, Li XY, Chen T, Zhuo M: Characterization of intrinsic properties of cingulate pyramidal neurons in control and neuropathic pain adult mice. Mol Pain 2009, 5: 73. 10.1186/1744-8069-5-73PubMed CentralPubMedView Article
- Ko S, Zhao MG, Toyoda H, Qiu CS, Zhuo M: Altered behavioral responses to noxious stimuli and fear in glutamate receptor 5 (GluR5)- or GluR6-deficient mice. J Neurosci 2005, 25: 977–984. 10.1523/JNEUROSCI.4059-04.2005PubMedView Article
- Wu LJ, Toyoda H, Zhao MG, Lee YS, Tang J, Ko SW, Jia YH, Shum FW, Zerbinatti CV, Bu G, et al.: Upregulation of forebrain NMDA NR2B receptors contributes to behavioral sensitization after inflammation. J Neurosci 2005, 25: 11107–11116. 10.1523/JNEUROSCI.1678-05.2005PubMedView Article
- Xu HWL, Wang H, Zhang X, Vadakkan KI, Kim SS, Steenland HW, Zhuo M: Presynaptic and postsynaptic amplifications of neuropathic pain in the anterior cingulate cortex. J Neurosci 2008, 28: 7445–7453. 10.1523/JNEUROSCI.1812-08.2008PubMed CentralPubMedView Article
- Zhao MG, Ko SW, Wu LJ, Toyoda H, Xu H, Quan J, Li J, Jia Y, Ren M, Xu ZC, et al.: Enhanced presynaptic neurotransmitter release in the anterior cingulate cortex of mice with chronic pain. J Neurosci 2006, 26: 8923–8930. 10.1523/JNEUROSCI.2103-06.2006PubMedView Article
- Zhao MG, Toyoda H, Lee YS, Wu LJ, Ko SW, Zhang XH, Jia Y, Shum F, Xu H, Li BM, et al.: Roles of NMDA NR2B subtype receptor in prefrontal long-term potentiation and contextual fear memory. Neuron 2005, 47: 859–872. 10.1016/j.neuron.2005.08.014PubMedView Article
- Shyu BC, Sikes RW, Vogt LJ, Vogt BA: Nociceptive processing by anterior cingulate pyramidal neurons. J Neurophysiol 2010, 103: 3287–3301. 10.1152/jn.00024.2010PubMed CentralPubMedView Article
- Wu LJ, Kim SS, Li X, Zhang F, Zhuo M: Sexual attraction enhances glutamate transmission in mammalian anterior cingulate cortex. Mol Brain 2009, 2: 9. 10.1186/1756-6606-2-9PubMed CentralPubMedView Article
- Doi A, Mizuno M, Katafuchi T, Furue H, Koga K, Yoshimura M: Slow oscillation of membrane currents mediated by glutamatergic inputs of rat somatosensory cortical neurons: in vivo patch-clamp analysis. Euro J Neurosci 2007, 26: 2565–2575. 10.1111/j.1460-9568.2007.05885.xView Article
- Petersen CCH, Hahn TTG, Mehta M, Grinvald A, Sakmann B: Interaction of sensory responses with spontaneous depolarization in layer 2/3 barrel cortex. Proc Natl Acad Sci USA 2003, 100: 13638–13643. 10.1073/pnas.2235811100PubMed CentralPubMedView Article
- Steriade M, Nunez A, Amzica F: A novel slow (< 1 Hz) oscillation of neocortical neurons in vivo: depolarizing and hyperpolarizing components. J Neurosci 1993, 13: 3252–3265.PubMed
- Furue H, Narikawa K, Kumamoto E, Yoshimura M: Responsiveness of rat substantia gelatinosa neurons to mechanical but not thermal stimuli revealed by in vivo patch-clamp recording. J Physiol 1999, 521: 529–535. 10.1111/j.1469-7793.1999.00529.xPubMed CentralPubMedView Article
- Kato G, Yasaka T, Katafuchi T, Furue H, Mizuno M, Iwamoto Y, Yoshimura M: Direct GABAergic and glycinergic inhibition of the substantia gelatinosa from the rostral ventromedial medulla revealed by in vivo patch-clamp analysis in rats. J Neurosci 2006, 26: 1787–1794. 10.1523/JNEUROSCI.4856-05.2006PubMedView Article
- Bean BP: The action potential in mammalian central neurons. Nat Rev Neurosci 2007, 8: 451–465. 10.1038/nrn2148PubMedView Article
- Brumberg JC, Nowak LG, McCormick DA: Ionic mechanisms underlying repetitive high-frequency burst firing in supragranular cortical neurons. J Neurosci 2000, 20: 4829–4843.PubMed
- Hara K, Harris RA: The anesthetic mechanism of urethane: the effects on neurotransmitter-gated ion channels. Anesth Analg 2002, 94: 313–318. 10.1097/00000539-200202000-00015PubMed
- Potez S, Larkum ME: Effect of common anesthetics on dendritic properties in layer 5 neocortical pyramidal neurons. J Neurophysiol 2008, 99: 1394–1407. 10.1152/jn.01126.2007PubMedView Article
- Shiraishi M, Harris RA: Effects of alcohols and anesthetics on recombinant voltage-gated Na+ channels. J Pharmacol Exp Ther 2004, 309: 987–994. 10.1124/jpet.103.064063PubMedView Article
- Yoshida MAA: Cell-type-specific modulation of intrinsic firing properties and subthreshold membrane oscillations by the M (Kv7)-current in neurons of the entorhinal cortex. J Neurophysiol 2007, 98: 2779–2794. 10.1152/jn.00033.2007PubMedView Article
- Yue C, Yaari Y: KCNQ/M channels control spike afterdepolarization and burst generation in hippocampal neurons. J Neurosci 2004, 24: 4614–4624. 10.1523/JNEUROSCI.0765-04.2004PubMedView Article
- Hefti BJ, Smith PH: Anatomy, physiology, and synaptic responses of rat layer V auditory cortical cells and effects of intracellular GABA(A) blockade. J Neurophysiol 2000, 83: 2626–2638.PubMed
- Hefti BJ, Smith PH: Distribution and kinetic properties of GABAergic inputs to layer V pyramidal cells in rat auditory cortex. J Assoc Res Otolaryngol 2003, 4: 106–121. 10.1007/s10162-002-3012-zPubMed CentralPubMedView Article
- Schubert D, Staiger JF, Cho N, Kötter R, Zilles K, Luhmann HJ: Layer-specific intracolumnar and transcolumnar functional connectivity of layer V pyramidal cells in rat barrel cortex. J Neurosci 2001, 21: 3580–3592.PubMed
- Shibata H: Efferent projections from the anterior thalamic nuclei to the cingulate cortex in the rat. J Comp Neurol 1993, 330: 533–542. 10.1002/cne.903300409PubMedView Article
- Wang CC, Shyu BC: Differential projections from the mediodorsal and centrolateral thalamic nuclei to the frontal cortex in rats. Brain Res 2004, 995: 226–235. 10.1016/j.brainres.2003.10.006PubMedView Article
- Yamamura HIK, Tsuboi Y, Toda K, Kitajima K, Shimizu N, Nomura H, Hibiya J, Fujita S, Sumino R: Morphological and electrophysiological properties of ACCx nociceptive neurons in rats. Brain Res 1996, 73: 83–92.View Article
- Lei LG, Sun S, Gao YJ, Zhao ZQ, Zhang YQ: NMDA receptors in the anterior cingulate cortex mediate pain-related aversion. Exp Neurol 2004, 189: 413–421. 10.1016/j.expneurol.2004.06.012PubMedView Article
- Tang J, Ko S, Ding HK, Qiu CS, Calejesan AA, Zhuo M: Pavlovian fear memory induced by activation in the anterior cingulated cortex. Mol Pain 2005, 1: 6. 10.1186/1744-8069-1-6PubMed CentralPubMedView Article
- Franklin KBJ, Paxinos G: The mouse brain in stereotaxic coordinates. 3rd edition. San Deigo: Academic Press; 1997.
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