Search results for "BLINKING"
showing 9 items of 39 documents
Electrophysiological brain stem investigations in idiopathic narcolepsy.
1998
Narcolepsy is associated with various rapid eye movement (REM) sleep abnormalities. Distinct brain stem areas seem to play a prominent role in REM sleep regulation. Recent magnetic resonance imaging (MRI) studies have led to conflicting findings concerning the presence of structural brain stem lesions in patients with idiopathic narcoleptic syndrome. However, multimodal electrophysiological brain stem investigations may reveal functional brain stem abnormalities even in the absence of MRI abnormality. Therefore we investigated brain stem function in 12 idiopathic narcoleptic patients by systematically studying tegmental brain stem pathways. All of the patients met the diagnostic criteria of…
Discerning the Origins of the Amplitude Fluctuations in Dynamic Raman Nanospectroscopy
2012
International audience; We introduce a novel experimental and analytical method for discerning rare surface-enhanced Raman scattering (SERS) events observable at the nanoscale. We show that the kinetics of the Raman activity recorded on an isolated nanostructure is punctuated by intense and rare events of large amplitude and spectral variations. The fluctuations of thousands of SERS spectra were analyzed statistically in terms of power density functions, and the occurrence of the rare events was quantified by a wavenumber statistics. Our analysis enables one to extract valuable and unique spectroscopic signature of Raman variations usually hidden in time-average or space-average measurement…
Hippocampal theta activity is selectively associated with contingency detection but not discrimination in rabbit discrimination-reversal eyeblink con…
2009
The relative power of the hippocampal theta-band ( approximately 6 Hz) activity (theta ratio) is thought to reflect a distinct neural state and has been shown to affect learning rate in classical eyeblink conditioning in rabbits. We sought to determine if the theta ratio is mostly related to the detection of the contingency between the stimuli used in conditioning or also to the learning of more complex inhibitory associations when a highly demanding delay discrimination-reversal eyeblink conditioning paradigm is used. A high hippocampal theta ratio was not only associated with a fast increase in conditioned responding in general but also correlated with slow emergence of discriminative res…
The effect of rewarding hypothalamic stimulation on behavioral and neural hippocampal responses during trace eyeblink conditioning in rabbit (Oryctol…
2005
Rabbits were trace-conditioned with a tone as a conditioned stimulus and an airpuff as an unconditioned stimulus. Electrical stimulation to the medial forebrain bundle in the lateral hypothalamus was delivered either before or after the tone-airpuff pair. The purpose of the present study was to test whether the effect of post-trial hypothalamic stimulation differed from the effect of pre-trial hypothalamic stimulation on trace conditioning in the same subjects. Additionally, hippocampal responses were measured during sessions to see if hypothalamic stimulation activated dopaminergic fibres and affected hippocampal cell functioning and thus learning. The results showed that behavioral nictit…
Inactivation of the interpositus nucleus blocks the conditioned response acquired by a somatosensory conditioned stimulus in rabbit eyeblink conditio…
2001
1. Earlier studies suggest that the memory trace for the conditioned eyeblink reflex is formed and maintained in the interpositus nucleus (IPN) in the deep cerebellar nuclei when either an auditory or visual stimulus is used as a conditioned stimulus (CS). 2. In the present study, the eyeblink reflex of the rabbit was conditioned to a somatosensory CS (an airpuff onto the back). 3. In well-trained animals, the IPN was reversibly inactivated by local cooling and the existence of the learned responses to the CS was then tested. 4. The reversible IPN inactivation blocked the memory trace the somatosensory CS. The finding further supports the view that IPN-mediated memory trace formation is not…
Most hippocampal CA1 pyramidal cells in rabbits increase firing during awake sharp-wave ripples and some do so in response to external stimulation an…
2020
Hippocampus forms neural representations of real-life events including multimodal information of spatial and temporal context. These representations, i.e. organized sequences of neuronal firing are repeated during following rest and sleep, especially when so-called sharp-wave ripples (SPW-Rs) characterize hippocampal local-field potentials. This SPW-R –related replay is thought to underlie memory consolidation. Here, we set out to explore how hippocampal CA1 pyramidal cells respond to the conditioned stimulus during trace eyeblink conditioning and how these responses manifest during SPW-Rs in awake adult female New Zealand White rabbits. Based on reports in rodents, we expected SPW-Rs to ta…
Use of digital displays and ocular surface alterations: A review.
2020
Digital display use has been accepted to be implicated as a contributing factor for dry eye disease (DED). Abnormal blinking during computer operation, including a reduced blink rate and an incomplete eyelid closure, increased palpebral fissure as consequence of high visualization angles, and meibomian gland dysfunction associated to long-term display use, are behind the increased prevalence of dry eye signs and symptoms found in digital display users. Previous research reveals significant reductions in tear volume and stability, alterations in tear film composition, including increased osmolarity, inflammatory cytokines, oxidative stress markers and reduced mucin secretion, eyelid abnormal…
Role of the tear film in the optical quality of the human eye.
2007
This paper reviews recent studies of the role of the tear film in the optical quality of the eye. Recent investigations focus on the dynamics of the tear film after a blink and its important role in the optical quality of the eye. The results in this review were used in an attempt to understand the optical and visual impact of tear-film breakup in normal eyes and dry eyes. It was noted that patients with dry-eye syndrome have large optical aberrations compared with those in normal eyes, which may be the cause of blurry vision associated with the syndrome. In addition, instillation of artificial tears reduces optical aberrations and thus improves the optical quality of vision in these patien…
Cardiac cycle and respiration phase affect responses to the conditioned stimulus in young adults trained in trace eyeblink conditioning
2022
Rhythms of breathing and heartbeat are linked to each other as well as to rhythms of the brain. Our recent studies suggest that presenting the conditioned stimulus during expiration or during the diastolic phase of the cardiac cycle facilitates neural processing of that stimulus and improves learning an eyeblink classical conditioning task. To date, it has not been examined whether utilizing information from both respiration and cardiac cycle phases simultaneously allows even more efficient modulation of learning. Here we studied whether the timing of the conditioned stimulus to different cardiorespiratory rhythm phase combinations affects learning trace eyeblink conditioning in healthy you…