The pedunculopontine nucleus (PPN), the cholinergic arm of the reticular activating system (RAS), is known to modulate waking and rapid eye movement (REM) sleep. REM sleep decreases between 10 and 30 days postnatally in the rat, with the majority occurring between 12 and 21 days. We investigated the possibility that changes in the cholinergic, muscarinic and/or nicotinic, input to PPN neurons could explain at least part of the developmental decrease in REM sleep. We recorded intracellularly from PPN neurons in 12-21 day rat brainstem slices maintained in artificial cerebrospinal fluid (aCSF) and found that application of the nicotinic agonist 1,1-dimethyl-4-phenyl-piperazinium iodide (DMPP) depolarized PPN neurons early in development, then hyperpolarized PPN neurons by day 21. Most of the effects of DMPP persisted following application of the sodium channel blocker tetrodotoxin (TTX), and in the presence of glutamatergic, serotonergic, noradrenergic and GABAergic antagonists, but were blocked by the nicotinic antagonist mecamylamine (MEC). The mixed muscarinic agonist carbachol (CAR) hyperpolarized all type II (A current) PPN cells and depolarized all type I (low threshold spike-LTS current) and type III (A + LTS current) PPN cells, but did not change effects during the period known for the developmental decrease in REM sleep. The effects of CAR persisted in the presence of TTX but were mostly blocked by the muscarinic antagonist atropine (ATR), and the remainder by MEC. We conclude that, while the nicotinic inputs to the PPN may help modulate the developmental decrease in REM sleep, the muscarinic inputs appear to modulate different types of cells differentially.

Rapid eye movement sleep decreases between 10 and 30 days postnatally in the rat. The pedunculopontine nucleus is known to modulate waking and rapid eye movement sleep, and pedunculopontine nucleus neurons are thought to be hyperpolarized by noradrenergic input from the locus coeruleus. The goal of the study was to investigate the possibility that a change in α-2 adrenergic inhibition of pedunculopontine nucleus cells during this period could explain at least part of the developmental decrease in rapid eye movement sleep. We, therefore, recorded intracellularly in 12-21 day rat brainstem slices maintained in oxygenated artificial cerebrospinal fluid. Putative cholinergic vs. non-cholinergic pedunculopontine nucleus neurons were identified using nicotinamide adenine dinucleotide phosphate diaphorase histochemistry and intracellular injection of neurobiotin (Texas Red immunocytochemistry). Pedunculopontine nucleus neurons also were identified by intrinsic membrane properties, type I (low threshold spike), type II (A) and type III (A+low threshold spike), as previously described. Clonidine (20 μM) hyperpolarized most cholinergic and non-cholinergic pedunculopontine nucleus cells. This hyperpolarization decreased significantly in amplitude (mean±S.E.) from -6.8±1.0 mV at 12-13 days, to -3.0±0.7 mV at 20-21 days. However, much of these early effects (12-15 days) were indirect such that direct effects (tested following sodium channel blockade with tetrodotoxin (0.3 μM)) resulted in hyperpolarization averaging -3.4±0.5 mV, similar to that evident at 16-21 days. Non-cholinergic cells were less hyperpolarized than cholinergic cells at 12-13 days (-1.6±0.3 mV), but equally hyperpolarized at 20-21 days (-3.3±1.3 mV). In those cells tested, hyperpolarization was blocked by yohimbine, an α-2 adrenergic receptor antagonist (1.5 μM). These results suggest that the α-2 adrenergic receptor on cholinergic pedunculopontine nucleus neurons activated by clonidine may play only a modest role, if any, in the developmental decrease in rapid eye movement sleep. Clonidine blocked or reduced the hyperpolarization-activated inward cation conductance, so that its effects on the firing rate of a specific population of pedunculopontine nucleus neurons could be significant. In conclusion, the α-2 adrenergic input to pedunculopontine nucleus neurons appears to consistently modulate the firing rate of cholinergic and non-cholinergic pedunculopontine nucleus neurons, with important effects on the regulation of sleep-wake states.

Music’s allure lies in its power to stir the emotions. But the relation between the physical properties of an acoustic signal and its emotional impact remains an open area of research. This paper reports the results and possible implications of a pilot study and survey used to construct an emotion index for subjective ratings of music. The dimensions of pleasure and arousal exhibit high reliability. Eighty-five participants’ ratings of 100 song excerpts are used to benchmark the predictive accuracy of several combinations of acoustic preprocessing and statistical learning algorithms. The Euclidean distance between acoustic representations of an excerpt and corresponding emotionweighted visualizations of a corpus of music excerpts provided predictor variables for linear regression that resulted in the highest predictive accuracy of mean pleasure and arousal values of test songs. This new technique also generated visualizations that show how rhythm, pitch, and loudness interrelate to influence our appreciation of the emotional content of music.

The overarching purpose of this work is to expand the utility of pupillometry as a non-invasive index of pupil-linked neuromodulatory systems, which are correlated with behavior states and are integral in carrying out complex behaviors, such as decision-making. The work characterizes tonic pupil dynamics and their relation to brain state and behavior (B. J. Schriver, S. Bagdasarov, & Q. Wang, 2018), characterizes the mechanisms and functional consequences behind phasic arousal linked pupil dynamics, and examines the causal role of the locus coeruleus in mediating the relationship between pupil dynamics, arousal, and ultimately behavior. For characterization of tonic pupil dynamics in the awake, behaving animal, rats were shown to be able to discriminate between directions of whisker deflections in a Go/No-Go behavioral paradigm with behavioral outcomes being associated with unique pupil dynamics. Furthermore, pupil baseline was inversely correlated with pupil dilation. Our work found that the behavior of rats performing the tactile discrimination task was highly dependent on pupil-indexed level of arousal. Pupil baseline exhibited an inverted U-shaped relationship with perceptual sensitivity and a U-shaped relationship with decision criterion. Shorter reaction times were also associated with higher perceptual sensitivity, more liberal decision criterion, and larger pupil baseline. We also found that behavioral outcomes influenced upcoming pupil dynamics and behavior. Altogether, we observed that there existed tight correlations between pupil dynamics, perceptual performance, and reaction time, all of which were influenced by fluctuating behavior state. For characterization of the mechanisms and functional consequences behind phasic pupil dynamics in the awake, behaving animal, task-evoked pupil responses were first shown to differ according to their underlying cognitive processes. Task-evoked pupil responses are composed of a superposition of elementary components and this work showed that individual responses could be decomposed into the sum of their weighted, time-locked generalizable pupil-linked phasic arousal inputs. These phasic arousal inputs were separate from inputs controlling baseline related arousal fluctuations. We found distinct contributions to phasic arousal were made by stimulus encoding and decision-formation. Looking at these independently suggested differences in the underlying phasic arousal related mechanisms in driving the animals towards outcomes contingent on stimulus identity. Furthermore, drift-diffusion modeling revealed that interplay between phasic arousal evoked by both stimulus encoding and decision formation had important functional consequences on forming behavioral choice in perceptual decision-making. We also observed a central role of the locus coeruleus-norepinephrine (LC-NE) system in modulating pupil-linked behavioral state. Both electrical and optogenetic activation of the LC-NE system mediated pupil dilation. Furthermore, trial-by-trial LC-NE system activation via channelrhodopsin-2 (ChR2) increased perceptual sensitivity in a difficulty dependent manner, with more pronounced improvement occurring when distracting stimuli were more similar to the target stimulus.

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This study examined the impact of divided attention tasks on stress using physiologic measures. The divided attention conditions included speech tasks (conversation or procedural discourse) and non-speech computer-based tasks (visuospatial, mathematical, language, data entry, or text editing). Participants included 60 adults divided into two groups of 30 by age. The young adult group ranged in age from 18-30 years and the older adults ranged from 55-82 years. Participants were required to perform the speech task and the non-speech task in isolation as well as a speech task performed concurrently with each of the non-speech tasks. The order of the tasks was randomized between participants to reduce sequencing effects. Physiologic measures include heart rate (HR), heart rate variability (HRV), and galvanic skin response (GSR) using a physiologic measurement system. Statistical analysis revealed age-related physiologic differences during the performance of all tasks. All GSR measures were significantly lower in older adults. Findings also provide insight into the physiologic response to dual-task conditions. The GSR levels were lower in concurrent conditions when compared to the conversation only tasks. Additionally, GSR levels increased during math tasks when compared to visuospatial or language tasks. The results provided insight into the physiologic response to divided attention tasks. The lack of a resting baseline condition and the effects of age on the dependent measures complicated the interpretation of the findings. Further research is needed to better understand the impact of divided attention tasks on a speaker’s physiologic stress response.

Prenatal sensory stimulation can have facilitative or interfering effects upon subsequent perceptual learning and development in bobwhite quail. Exposure to moderate amounts of unimodal prenatal sensory stimulation has been shown to accelerate early intersensory responsiveness, while exposure to concurrent prenatal bimodal sensory stimulation has been shown to interfere with perceptual learning and development. An immediate mechanism that may underlie this developmental intersensory interference is the arousal level of the organism associated with exposure to prenatal bimodal stimulation. Concurrent bimodal stimulation is known to elicit significantly higher levels of behavioral arousal and heart rate in bobwhite quail embryos. This study investigated the possibility that increased arousal associated with prenatal bimodal stimulation could have enduring effects upon subsequent postnatal behavioral organization and perceptual abilities in bobwhite quail. Subjects were exposed to one of three prenatal stimulation regimes: (a) concurrent bimodal (auditory/visual) stimulation, (b) unimodal auditory stimulation, or (c) no supplemental stimulation. Chicks exposed to concurrent prenatal bimodal stimulation demonstrated significantly greater levels of behavioral activity as well as decreased social behavior in the open-field when compared to unimodal auditory subjects and controls. Additionally, prenatal bimodal exposure may have led to a failure to utilize multimodal maternal cues in determining species-specific perceptual preferences in the days following hatching. All exposure groups demonstrated postnatal auditory learning of a maternal call, thus no interference effect was found for concurrent prenatal bimodal stimulation on postnatal auditory learning. These results suggest that concurrent prenatal bimodal stimulation has enduring effects upon postnatal behavioral arousal that may impact perceptual responsiveness of bobwhite quail in the days following hatching. / Ph. D.

Syftet med denna uppsats bestod dels i att undersöka hur musik och dess tempo påverkar kunders emotioner, beteende och upplevelse i butik, men syftade även till att undersöka i vilken omfattning pleasure, arousal och dominance predicerar tillfredsställelse, närmande- undvikande sökbeteende, generell närmande- undvikande beteende samt upplevelse av servicescape. Undersökningen genomfördes som ett fältexperiment i butiksmiljö (N= 431), utifrån en oberoende mellan-individ-design. Musik användes som oberoende variabel (högt tempo, lågt tempo och frånvaro av musik). De beroende variablerna var pleasure, arousal och dominance, tillfredsställelse samt närmande- undvikande beteende vari även köp och spenderad tid i butik inkluderades. Datainsamlingsmetod utgjordes av en enkät. Resultatet visade signifikant att musik påverkar ny dominance utifrån att musik med högt tempo leder till lägre grad av kontroll. Resultatet visade även att kunders emotioner så som pleasure, arousal och dominance signifikant förklarar kunders tillfredsställelse, närmande- undvikande sökbeteende, generell närmande- undvikande beteende samt upplevelse av servicescape. / The purpose of this study consisted in examining how the music and the tempo affect customers' emotions, behavior and experience in stores but also aimed to examine the extent of pleasure, arousal and dominance predicts satisfaction, approach-avoidance search behavior, generalized approach-avoidance behavior and experience of servicescape. The survey was conducted as a field experiment in a retail environment (N= 431), based on an independent between-subject design. Music was used as the independent variable (high speed, low speed and absence of music). The dependent variables were pleasure, arousal and dominance, satisfaction and approach-avoidance behavior whereby purchase and time spent in the store was included. Data collection method consisted of a questionnaire. The results showed significant that music tempo affects new dominance based on the music with high tempo leads to lower degree of control. The results also showed that customers’ emotions such as pleasure, arousal and dominance significantly explains customers satisfaction, approach-avoidance search behavior, generalized approach-avoidance behavior and experience of servicescape.