The boundaries between normal and pathological categories were po

The boundaries between normal and pathological categories were portrayed as particularly rigid when the pathological phenomenon in question had a moral dimension. Emphasizing such groups’ neurobiological deviance may serve the function of symbolically distancing the “normal” majority from the morally

contaminated phenomenon. “The brains of paedophiles may work differently from others, GSK-3 inhibitor scientists claimed yesterday. They found distinct differences in brain activity among adults who had committed sexual offences involving young children.” (Daily Mail, September 25, 2007) Although separating the normal and abnormal was important in the data, also present (though less prominent) was discussion of neuroscience in ways that elided the normal-abnormal split. This often involved co-opting previously normal behaviors and feelings into the pathological domain.

A common example was the application of the terminology of addiction to a wide range of everyday behavioral domains, from shopping to computers, sex, chocolate, exercise, adventure sports, and sunbathing. “Brain-imaging scientists have AZD8055 solubility dmso discovered why breaking up can be so hard to do: the neurologists say that it is because pining after your lost love can turn into a physically addictive pleasure.” (Times, June 28, 2008) Thus, media coverage of neurobiological differences reinforced divisions between social groups and was presented in stereotype-consistent ways. Delineating the boundary between the normal and the pathological was an underlying concern in many articles, but some subverted this to blur the normal-abnormal boundary and portray commonplace activities as pathological. The final theme captures the deployment of neuroscience to demonstrate the material, neurobiological basis of particular beliefs or phenomena. This was

presented and as evidence of their validity and was sometimes used for rhetorical effect. This theme traversed most of the code categories but was particularly salient within applied contexts, basic functions, sexuality, and spiritual experiences. The brain operated as a reference point on which the reality of contested or ephemeral phenomena was substantiated. For example, religious experiences, medically puzzling health conditions, and supernatural phenomena were reconstituted as manifestations of neural events. This validated the existence of such experiences—people who have experienced them are not deluded or hysterical—through bringing them into the physical domain and divesting them of their ethereal or contested qualities. “But rather than being a brush with the afterlife, near-death experiences may simply be caused by an electrical storm in the dying brain.” (Daily Mail, May 31, 2010) In social discourse, what is “natural” is often equated with what is just or right: implicit in the descriptive “is” statement is a normative “ought” statement.

, 2008), the two modes of division seem to occur in distinct subp

, 2008), the two modes of division seem to occur in distinct subpopulations of RGCs. BIBW2992 Whether or not the orientation of RGC divisions is relevant for neurogenesis has been a matter of intense debate. Early reports have demonstrated that vertical spindle orientation

correlates with an asymmetric outcome in terms of daughter cell fates (Chenn and McConnell, 1995 and Zhong and Chia, 2008), leading to models in which the unequal segregation of the apical and basal plasma membranes directs cell fate (Zhong and Chia, 2008). Consistent with this, mitotic spindles with vertical orientations are only found during the neurogenic phases of brain development (Haydar et al., 2003), while during the early expansion phase, keeping precise horizontal spindle orientation is crucial to maintain the neural progenitor pool (Fish et al., 2006 and Yingling et al., 2008). The frequency of vertical divisions during the neurogenic phase, however, is too low to account for all divisions with asymmetric outcome (Chenn and McConnell, 1995, Haydar et al., 2003 and Kosodo et al., 2004). This could be explained by the small size of the apical membrane domain of RGCs, such that even barely oblique mitotic spindles would give rise to cleavage planes that fail to bisect this domain resulting in its asymmetric segregation (Kosodo et al., 2004). It has been demonstrated that increasing the rate of vertical

Ulixertinib research buy divisions can affect progenitor cell number and location (Konno et al., 2008 and Shitamukai et al., 2011). Functional evidence to demonstrate that either vertical or oblique spindle orientation is required for neurogenesis, however, remains to be established. The molecular machinery for spindle orientation during neurogenesis is best understood in Drosophila ( Siller and Doe, 2009). In Drosophila neuroblasts, orientation of the mitotic spindle along the apical-basal axis is important

for the asymmetric segregation of the cell fate determinants Numb ( Hirata et al., 1995, Knoblich Etomidate et al., 1995, Rhyu et al., 1994 and Spana and Doe, 1995), Prospero ( Hirata et al., 1995, Knoblich et al., 1995 and Spana and Doe, 1995), and Brat ( Bello et al., 2006, Betschinger et al., 2006 and Lee et al., 2006) into the basal daughter cell ( Bowman et al., 2006, Izumi et al., 2006 and Siller et al., 2006), where these proteins prevent self-renewal and induce differentiation. In neuroblasts, the mitotic spindle is oriented by two protein complexes that assemble on its apical cell cortex. One complex consists of the PDZ domain proteins Par-3, Par-6, and the atypical protein kinase C (aPKC) while the other contains the GoLoco domain protein Pins, the heterotrimeric G protein subunit GαI, and the microtubule-binding protein Mushroom body defect (Mud). These two complexes are linked by an adaptor protein called Inscuteable (Insc). Insc can bind to both Pins ( Schaefer et al., 2000 and Yu et al., 2000) and Par-3 ( Schober et al., 1999 and Wodarz et al.

, 2009) These studies suggest that while selective attention can

, 2009). These studies suggest that while selective attention can preferentially enhance the responses to the attended stimuli, a general increase

in vigilance may in fact reduce the overall response in order to accentuate representation of the relevant stimulus (Atiani et al., 2009). In contrast to the findings above, a drug discovery study in mouse visual cortex showed that the neuronal responses to drifting grating stimuli are much higher when the mouse was behaviorally active (running) than inactive (standing still) (Niell and Stryker, 2010). One factor that may contribute to the discrepancy among these experiments is the use of transient (e.g., a brief sound or tactile stimulus) versus sustained (e.g., drifting gratings) sensory stimuli, which evoke different degrees of neuronal adaptation (Harris selleck and Thiele, 2011), as strong adaptation is observed primarily in behaviorally inactive states (Castro-Alamancos, 2004a). More importantly, the modulation of sensory responses by different behaviors—selective attention to a single stimulus, nonselective increase in vigilance, and general behavioral arousal (e.g., running)—may be mediated by different mechanisms, involving partially overlapping but nonidentical sets of neuromodulatory inputs. Testing this hypothesis will require simultaneous measurement of activity of both the neuromodulatory systems and the sensory neurons under the

different behavioral paradigms. Optogenetic manipulation of each neuromodulatory system (Figures 4C and 4D) will also reveal its impact on the activity of sensory neurons within each behavioral context. While it is well accepted that the aroused, attentive states are favorable for sensory processing, what are the functions of the synchronized brain states? In particular, why is sleep so universal in the animal isothipendyl kingdom (Cirelli and Tononi, 2008), given that the loss of responsiveness to environmental stimuli makes the animal more vulnerable to predator attacks?

The importance of sleep can be appreciated from the severe effects of sleep deprivation on cognitive functions and general health. Prolonged total sleep deprivation is known to be lethal in flies (Shaw et al., 2002) and rats (Rechtschaffen and Bergmann, 2002), although some of the harmful effects may be attributable to the stress induced by the experimental methods of deprivation. Specifically, one function of sleep may be energy conservation or brain recuperation (Siegel, 2005). A recent study showed that the ATP concentration surges in the first few hours of sleep, and the level of surge is correlated with the EEG delta activity during NREM sleep (Dworak et al., 2010). However, the cause for this energy surge may not be a simple reduction of neuronal activity. We know that during NREM sleep many neurons remain highly active, and the difference from the awake state resides more in the spatiotemporal pattern than in the overall level of neural activity.

We argue that this was associated—at least partly—with compatible

We argue that this was associated—at least partly—with compatible

changes in self-location (mental ball dropping task): a low position Selleck Cabozantinib or level of self-location (comparable to those indicated during the control conditions; see blue line in Figure 2A) and a drift in self-location characterized by an elevation during synchronous versus asynchronous stroking (difference between the two gray bodies in Figure 2A). This was different in participants from the Down-group. They felt themselves to be looking down at the body below them (different from participants from the Up-group), self-identified with that body during synchronous stimulation (as participants from the Up-group), and experienced themselves to be spatially closer with the virtual body during

synchronous stimulation (as participants from the Up-group). We note that some free reports also suggested that they experienced themselves to be floating and to be elevated during asynchronous stroking. This was associated—at least partly—with compatible changes in self-location (mental ball dropping task): a high position or level of self-location during asynchronous stroking (comparable to those indicated during the control conditions; see blue lines in Figure 2B) and a drift in self-location characterized by a descent during synchronous versus asynchronous stroking (difference between the two gray bodies in Figure 2B that is opposite in direction with respect to the drift-related change in self-location selleck kinase inhibitor in the Up-group; black arrows in Figure 2). We next analyzed whether changes in illusory self-location—based on the experimental factors of Stroking, Object, and Perspective—were reflected in the fMRI data. Group-level whole-brain

analysis indicated seven cortical regions where the BOLD signal was significantly different during any of the eight conditions Edoxaban compared to the baseline condition (Figure 4). These regions (Table S2) were located at the left and right temporo-parietal junction (TPJ), left and right postcentral gyrus (Figures 4A–4C), left and right temporo-occipital cortex (posterior middle and inferior temporal gyri, or extrastriate body area; EBA), and bilateral occipital lobe (Figure 4D). To target brain regions reflecting self-location (as measured by the MBD task; Figure 2) we searched for activity that could not be accounted for by the summation of the effects of seeing the body, feeling synchronous stroking, and the spontaneously reported perspective. Based on our subjective and behavioral data on self-location, we searched for BOLD responses that reflected changes in self-location (i.e., BOLD responses that depend on Stroking and Object), and that also differed for the two perspective groups.

Interestingly, NDR1-CA also caused a reduction in mEPSC frequency

Interestingly, NDR1-CA also caused a reduction in mEPSC frequency indicating that uncontrolled NDR1 activity can also inhibit active synapse formation (Figure 3F). We did not find a difference in mEPSC amplitude (Figure 3G), suggesting that NDR activity affects the number of active synapses rather than the strength of each synapse. Furthermore, coimmunostaining with post- and presynaptic markers indicate that synapses are most often made directly on dendritic shaft in NDR1-CA-expressing neurons in contrast to neurons expressing NDR1-KD or GFP alone (Figure S3A). These observations indicate that mEPSCs in NDR1-CA BKM120 in vitro neurons could originate from synapses on

dendritic shafts and support the notion that the reductions in the total number of synapses in NDR1-KD- and NDR1-CA-expressing neurons leads to reduced mEPSC frequency. Our data revealed that both loss and gain of function of NDR1/2 altered spine morphogenesis. NDR1/2 loss of function reduced mushroom

spines and increased filopodia and atypical protrusions. The reduction in mushroom spines is reflected in reduced mEPSC frequency. In contrast, uncontrolled NDR1-CA activity led to retraction of all dendritic protrusions, most likely via a mechanism distinct from the process for mushroom spine formation. The reduction in mushroom spines, along with other dendritic GS-1101 protrusions, is also reflected in reduced mEPSC frequency. Thus, our data indicate that strictly controlled NDR1/2 activity is required for proper dendritic spine development. We next altered NDR1/2 function in layer 2/3 cortical pyramidal neurons in vivo by expression of dominant negative or constitutively active NDR1, as well as siRNA, via in utero electroporation at embryonic day (E)14.5–E15.5. Analysis of labeled layer 2/3 neurons in P18–P20 brains revealed no effect on neuronal migration by NDR1/2 3-mercaptopyruvate sulfurtransferase manipulations (data not shown). We measured dendritic arborization within 150 μm from the soma, which included basal dendrites, and proximal

region of the apical dendrite. The apical tufts were not included in the analysis, because they were mostly cut away in our sections. We found that NDR1-KD or NDR1siRNA + NDR2siRNA expression (which reduces NDR1 and NDR2, respectively; Figures S3E and S7B) increased dendrite branching at 50 μm from the soma and the total dendrite length, when compared with vector control and control-siRNA, respectively (Figures 4A, 4B, 4D–4F). In contrast, NDR1-CA expression dramatically reduced branching and dendrite length (Figures 4A, 4B, 4D–4F), the reduction in branching was uniformly apparent in all GFP-expressing cells (Figure S3B). NDR1-CA-expressing neurons appeared healthy (Figures S3C and S3D).

3 ± 3 0 mV; median 6 7 mV; range 0 5 to 11 0 mV); latency (mean 8

3 ± 3.0 mV; median 6.7 mV; range 0.5 to 11.0 mV); latency (mean 8.6 ± 2.7 ms; median 8.7 ms; range 5.3 to 12.7 ms); time-to-peak (mean 16.0 ± 9.9 ms; median 13.8 ms; range 4.9 to 37.2 ms); duration (mean 52.5 ± 27.0 ms; median 51.8 ms; range 9.1 to 103.1 ms); and rate of rise (slope, mean 0.56 ± 0.49 V/s; median 0.41 V/s; range 0.09 to 1.52 V/s) (Figures 4B). Cells with shorter latency tended to exhibit larger-amplitude subthreshold responses and neurons exhibiting a fast time-to-peak also tended to have a shorter-duration response (data not shown). Neurons recorded deeper Selleck Lumacaftor in L2/3 responded with PSPs of larger-amplitude depolarizations, shorter latencies, shorter-duration

responses, and faster rates of rise (PSP slope) (Figure 4B). Therefore, deeper neurons, located

in layer 3, preferentially signal each individual contact with high temporal precision, whereas the more superficial layer 2 neurons preferentially integrate touch responses over a longer timescale. Nine identified layer 2/3 pyramidal neurons were recorded in adjacent barrel columns (Table S1). The grand averaged response to active touch of the C2 whisker with an object reveals a smaller amplitude response with longer latency in the surrounding cortical columns, but otherwise sharing a similar range of response properties (Figure S2). That the touch response spreads to neighboring columns is consistent with voltage-sensitive dye imaging data showing that a large area

of cortex can depolarize in response to single whisker active touch in awake mice RAD001 mw (Ferezou et al., 2007). These data are also consistent with the broad subthreshold receptive fields of layer 2/3 neurons evoked by passive whisker deflection recorded under anesthesia (Moore and Nelson, 1998, Zhu and Connors, 1999 and Brecht et al., 2003). Consecutive touches evoked different amplitude touch PSP responses (Figure 5A) (coefficient of variation mean ± SD 1.4 ± 0.7; median 1.0; range 0.4 to 3.1). Part of the variability of the touch response could be accounted for by considering the neuronal membrane potential immediately preceding the response onset, which profoundly influenced the PSP amplitude. Touch responses evoked at spontaneously hyperpolarized precontact Vm were larger in amplitude 4-Aminobutyrate aminotransferase compared to touch responses occurring during spontaneously depolarized membrane potentials (Figure 5B). Indeed, at the most depolarized precontact membrane potentials, the touch response was hyperpolarizing (Figure 5B). Plotting the active touch response amplitude as a function of the precontact Vm revealed a close to linear relationship (Figure 5C). The correlation between response amplitude and precontact Vm was significant (α = 0.05) in all 17 neurons tested (cell #36 had a complex depolarizing-hyperpolarizing response and was not included in the subsequent active touch response dynamic analysis; see Table S1). The mean coefficient of correlation was −0.

, 2002 and Lu et al , 2006b) While these studies have found rela

, 2002 and Lu et al., 2006b). While these studies have found relatively few Fos immunoreactive neurons in the PPT or LDT, Fos expression was elevated in three slightly more caudal cell groups: the sublaterodorsal nucleus (SLD), which is ventral and caudal to the LDT; the precoeruleus region (PC), which lies just dorsal to the SLD and caudal to the LDT; and the medial parabrachial nucleus (MPB), which is just dorsolateral to the SLD (Figure 2). The role of the SLD

in producing REM sleep has been studied by injecting it with bicuculline, A-1210477 clinical trial a GABA antagonist, which disinhibits the SLD neurons and elicits REM sleep-like behavior (Boissard et al., 2002). Lesions in the SLD region of cats, also called the subcoeruleus area, have been known since

the 1970s to disrupt atonia during REM sleep such that animals appear to act out their dreams (Hendricks et al., 1982, Sastre and Jouvet, 1979 and Shouse and Siegel, 1992). However, lesions of the SLD in rats have more profound effects, fragmenting and reducing the amount of REM sleep (Lu et al., SB203580 research buy 2006b). Injections of retrograde tracers into the SLD identified major GABAergic inputs from the vlPAG and adjacent lateral pontine tegmentum (LPT) (Boissard et al., 2003 and Lu et al., 2006b). This same region receives convergence of inputs from the extended VLPO and the orexin neurons in the lateral hypothalamus (Lu et al., 2006b). Because the extended VLPO neurons promote REM sleep but are inhibitory, and the orexin neurons prevent REM sleep and are excitatory, the vlPAG-LPT region would be expected to prevent REM sleep. As neurons in the vlPAG-LPT that project to the SLD are GABAergic, they would be expected to fire when REM sleep is inhibited (i.e., to show a REM-off firing pattern). Indeed, inhibition of the vlPAG and LPT with GABA agonists increases REM sleep (Crochet et al., 2006, Sapin et al., 2009 and Sastre et al., 1996), either and lesions increase REM sleep, particularly during the dark phase (Lu et al., 2006b). Injections

of retrograde tracers into the vlPAG and LPT demonstrate retrogradely labeled GABAergic neurons in the SLD and anterogradely labeled axons from the SLD are found in close apposition to GABAergic neurons in the vlPAG and LPT (Lu et al., 2006b). These findings suggest that the vlPAG-LPT and the SLD have a mutually inhibitory relationship that may govern switching in and out of REM sleep, much like the relationship between the VLPO and the ascending arousal systems, which we hypothesize is the basis for switching between sleep and wake states. Glutamatergic neurons that are mixed in with the REM-on GABAergic neurons give rise to long projections that activate the principle components of the REM state (Lu et al., 2006b, Luppi et al., 2004, Luppi et al., 2006, Shouse and Siegel, 1992 and Webster and Jones, 1988).

, 2003) FGF8 patterns the anterior cortex by suppressing in a do

, 2003). FGF8 patterns the anterior cortex by suppressing in a dose-dependent manner the anterior expression of Emx2 and CoupTF1, two transcription factors specifying posterior area identities. FGF8 also activates several transcription factors anteriorly including Sp8, which maintains the expression Epigenetics inhibitor of Fgf8 in a positive feedback loop (Cholfin

and Rubenstein, 2008, Garel et al., 2003 and O’Leary and Sahara, 2008; Figure 4C). Analysis of mice null mutant for FGF17, which is also secreted by the rostral signaling center, showed that this FGF has a more restricted role in telencephalic patterning and specifically controls the size and position of the dorsal frontal cortex (with important consequences for adult behavior that are discussed later) without affecting the development of the ventral frontal cortex, in contrast with FGF8 which regulates the size of both territories (Cholfin and Rubenstein, 2007 and Cholfin and Rubenstein, 2008). The divergent activities of FGF17 and FGF8 likely reflect spatio-temporal differences selleck chemicals in their expression within the rostral signaling center as well as different affinities for FGFRs. Analysis of mice null mutant for FGF15, a third FGF secreted anteriorly, revealed that this factor has a unique role among telencephalic FGFs as it opposes FGF8 function and

suppresses anterior telencephalic fates, at least in part by promoting expression of CoupTF1. Addition of FGF8 and FGF15 to cortical

cell cultures differentially activates several kinases acting downstream of FGFRs, suggesting that the two ligands interact with different FGFRs (Borello et al., 2008). In addition to their roles in the specification of areal identities, FGFs also control the differential growth of cortical subdomains, as discussed in the next section. A combination of experiments, including analysis whatever of FGF8 protein distribution, fate mapping of FGF8-expressing cells, and inhibition of FGF8 signaling with a dominant-negative version of FGFR3c, has demonstrated that FGF8 acts in the telencephalon as a classic morphogen. It forms a diffusion gradient across the entire antero-posterior extent of the telencephalic primordium and acts directly at a distance from its source to impart different positional identities at different concentrations (Toyoda et al., 2010). Similarly, secretion of FGFs by the isthmus produces a concentration gradient that generates graded patterns of gene expression in the midbrain (Chen et al., 2009). Direct examination of single molecules of green fluorescent protein (GFP)-tagged FGF8 in living zebrafish embryos showed that FGF8 diffuses in the extracellular space, with its signaling range being controlled by HSPGs and by receptor-mediated endocytosis in receiving cells (Yu et al., 2009).

To explore neuronal activity as a potential factor influencing th

To explore neuronal activity as a potential factor influencing the recycling pool fraction, we also carried out experiments using a lower frequency loading protocol (1,200 APs, 4 Hz).

We found that the mean recycling fraction (0.17 ± 0.01, n = 68) was essentially identical to the 10 Hz loading condition (p = 0.52, two-tailed Birinapant Mann-Whitney test) and similarly variable (Figure S2), suggesting that stimulus frequency was not a critical determinant of the functionally recruited pool size. Next, we used our ultrastructural readout of the functional vesicle pool to investigate the spatial organization of recycling vesicles within the presynaptic terminal (Figures 4A and 4B). First, we examined how recycling vesicles were mixed within the total vesicle pool by performing a cluster analysis (n = 368 photoconverted vesicles

from 31 synapses). Calculating the recycling fraction in the population of vesicles surrounding each PC+ vesicle at increasing distances from the vesicle center (Figure 4C, inset) showed that at a 50–70 nm radius, the recycling fraction was not significantly different from the baseline fraction for the whole synapse (p values > 0.09, two-tailed one-sample t tests, n = 31), demonstrating that recycling vesicles did not cluster at small distances (Figure 4C). However, a significant peak in the recycling fraction was seen at a 90–110 nm radius (p = 0.02, 0.04, two-tailed one-sample t test, n = 31), after which the fraction tends toward Selleck PD0332991 baseline levels as the distance radius approaches the total synapse size (all distances > 110 nm, p values = 0.06–0.98, two-tailed

one-sample t tests, n = 31). This demonstrates that recycling Astemizole vesicles tend to occupy a subset of the total pool area, suggesting a potential spatial bias in vesicle organization (see Figures 4A and 4B). To examine this directly, we analyzed representative middle sections of 24 synaptic terminals and measured the distance from each vesicle—both recycling and nonrecycling—to the nearest point on the active zone and generated cumulative frequency distance plots. These revealed that the distributions of the two populations were significantly different (p < 0.0001, two-tailed paired t test, n = 24), with recycling vesicles occupying positions closer to the active zone than nonrecycling vesicles (Figure 4D). Comparable findings were made for synapses labeled with 4 Hz loading (Figure S2). For the 10 Hz data, we also performed the same analysis on nine fully reconstructed synaptic terminals, which took into account the three-dimensional distance relationships, and this revealed the same preferential bias for recycling vesicles to be close to the release site (Figures 4E and 4F, p < 0.0001, two-tailed paired t test, n = 9).

Next, we investigated which sleep state might be responsible
<

Next, we investigated which sleep state might be responsible

for the global across-sleep changes of firing patterns. Since the duration of individual non-REM and REM episodes vary, their lengths were normalized (see Experimental Procedures) and the pattern of changes within episodes was quantified. In non-REM episodes, we found that firing rates significantly increased between the first and last thirds of the episodes, both in pyramidal cells (p < 1.99 × 10−14, n = 618) and in interneurons (p < 4.6 × 10−5, n = 111) (Figure 2A; Figure S2). Other measures, such as incidence of active and inactive epochs, the percentage of ripples in which pyramidal cells participated, and population synchrony, as measured by pyramidal cell pairwise correlations, EX 527 also showed significant and opposite changes within non-REM compared to those observed across sleep (Figure 2B). In contrast, firing rates significantly decreased within REM epochs, both in pyramidal cells (p < 0.012, n = 618) and in interneurons (p < 1.23 × 10−5, n = 111) (Figure 2A; Figure S2). In addition to unit firing, the LFP spectral changes across sleep were

also calculated. For each sleep session, the LFP spectra in individual non-REM and REM episodes, recorded RO4929097 clinical trial from the CA1 pyramidal layer, were normalized independently for each frequency by the power of concatenated non-REM episodes and expressed as a Z score. Spectral power decreased significantly in a broad range of frequencies (4–50 Hz) across sleep (i.e., from the first to last non-REM episode; Figure 3A; n = 22 sleep sessions; change in 0–50 Hz integrated power; p < 0.0024; sign-rank test). In contrast, a significant increase in power (0–50 Hz) was present within non-REM episodes ( Figure 3B; n = 82 non-REM episodes; p < 2.11 × 10−9; sign-rank test). Within REM episodes, a power decrease was observed in the theta-beta (5–20 Hz) and lower gamma (40–50 Hz) band ( Figure 3C; n = 45 REM episodes; of 0–50 Hz

power; p < 2.85 × 10−4; sign-rank test). Changes in the delta band (1–4 Hz) may reflect changes in the hippocampus or volume-conducted LFP from the neocortex ( Wolansky et al., 2006; Isomura et al., 2006). Since the evolution of firing patterns and LFP across sleep was similar to those observed within REM sleep but dissimilar to the changes observed within non-REM episodes, we examined how REM episodes might contribute to the overall reorganization of firing patterns during the course of sleep. The mean firing rate decrease of both the pyramidal cell and interneuron populations from the non-REM episode preceding a REM (non-REMn) to the non-REM episode after a REM episode (non-REMn+1) was significantly correlated with the theta power of the interleaving REM episode but not the power of other frequencies (Figures 4A and 4B), except for the lower gamma band for pyramidal cells.