Shu Kit Eric Tam

Journal Article Journal of behavioral addictions · March 2025 Behavioral addictions share symptomatological features with substance addiction. From the associative learning perspective, these characteristics include excessive and unregulated self-administration of sensory and other reinforcers, potentially reflecting ... Full text Open Access Cite

Offline hippocampal reactivation during dentate spikes supports flexible memory.

Journal Article Neuron · November 2024 Stabilizing new memories requires coordinated neuronal spiking activity during sleep. Hippocampal sharp-wave ripples (SWRs) in the cornu ammonis (CA) region and dentate spikes (DSs) in the dentate gyrus (DG) are prime candidate network events for supportin ... Full text Cite

Light sampling behaviour regulates circadian entrainment in mice.

Journal Article BMC biology · September 2024 BackgroundThe natural light environment is far more complex than that experienced by animals under laboratory conditions. As a burrowing species, wild mice are able to self-modulate their light exposure, a concept known as light environment sampli ... Full text Cite

Continuous home cage monitoring of activity and sleep in mice during repeated paroxetine treatment and discontinuation.

Journal Article Psychopharmacology · November 2023 RationaleNon-invasive home cage monitoring is emerging as a valuable tool to assess the effects of experimental interventions on mouse behaviour. A field in which these techniques may prove useful is the study of repeated selective serotonin reupt ... Full text Cite

Adult-born dentate granule cells promote hippocampal population sparsity.

Journal Article Nature neuroscience · November 2022 The dentate gyrus (DG) gates neocortical information flow to the hippocampus. Intriguingly, the DG also produces adult-born dentate granule cells (abDGCs) throughout the lifespan, but their contribution to downstream firing dynamics remains unclear. Here, ... Full text Cite

Effects of Cage Position and Light Transmission on Home Cage Activity and Circadian Entrainment in Mice

Journal Article Frontiers in Neuroscience · January 10, 2022 Light is known to exert powerful effects on behavior and physiology, including upon the amount and distribution of activity across the day/night cycle. Here we use home cage activity monitoring to measure the effect of differences in home cage light spectr ... Full text Cite

Rodent models in translational circadian photobiology.

Chapter · January 2022 Over the last decades remarkable advances have been made in the understanding of the photobiology of circadian rhythms. The identification of a third photoreceptive system in the mammalian eye, in addition to the rods and cones that mediate vision, has tra ... Full text Cite

Deletion of AMPA receptor GluA1 subunit gene (Gria1) causes circadian rhythm disruption and aberrant responses to environmental cues.

Journal Article Translational psychiatry · November 2021 Dysfunction of the glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluA1 subunit and deficits in synaptic plasticity are implicated in schizophrenia and sleep and circadian rhythm disruption. To investigate the role of GluA1 ... Full text Cite

Dim light in the evening causes coordinated realignment of circadian rhythms, sleep, and short-term memory.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · September 2021 Light provides the primary signal for entraining circadian rhythms to the day/night cycle. In addition to rods and cones, the retina contains a small population of photosensitive retinal ganglion cells (pRGCs) expressing the photopigment melanopsin (OPN4). ... Full text Cite

A role for the cortex in sleep-wake regulation.

Journal Article Nature neuroscience · September 2021 Cortical and subcortical circuitry are thought to play distinct roles in the generation of sleep oscillations and global state control, respectively. Here we silenced a subset of neocortical layer 5 pyramidal and archicortical dentate gyrus granule cells i ... Full text Cite

Modulation of recognition memory performance by light and its relationship with cortical EEG theta and gamma activities.

Journal Article Biochemical pharmacology · September 2021 Acute exposure to light exerts widespread effects on physiology, in addition to its key role in photoentrainment. Although the modulatory effect of light on physiological arousal is well demonstrated in mice, its effect on memory performance is inconclusiv ... Full text Cite

Continuous and non-invasive thermography of mouse skin accurately describes core body temperature patterns, but not absolute core temperature.

Journal Article Scientific reports · November 2020 Body temperature is an important physiological parameter in many studies of laboratory mice. Continuous assessment of body temperature has traditionally required surgical implantation of a telemeter, but this invasive procedure adversely impacts animal wel ... Full text Cite

Mechanisms mediating the effects of light on sleep and alertness: current challenges

Journal Article Current Opinion in Physiology · June 1, 2020 Light is an important environmental cue that exerts a direct and potent effect on vigilance states. In humans, light exposure increases subjective alertness and activates brain regions that are involved in promoting wakefulness. The spectral characteristic ... Full text Cite

Light and cognition: Roles for circadian rhythms, sleep, and arousal

Journal Article Frontiers in Neurology · February 9, 2018 Light exerts a wide range of effects on mammalian physiology and behavior. As well as synchronizing circadian rhythms to the external environment, light has been shown to modulate autonomic and neuroendocrine responses as well as regulating sleep and influ ... Full text Cite

Long-term restoration of visual function in end-stage retinal degeneration using subretinal human melanopsin gene therapy.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · October 2017 Optogenetic strategies to restore vision in patients who are blind from end-stage retinal degenerations aim to render remaining retinal cells light sensitive once photoreceptors are lost. Here, we assessed long-term functional outcomes following subretinal ... Full text Cite

Constant Light Desynchronizes Olfactory versus Object and Visuospatial Recognition Memory Performance.

Journal Article The Journal of neuroscience : the official journal of the Society for Neuroscience · March 2017 Circadian rhythms optimize physiology and behavior to the varying demands of the 24 h day. The master circadian clock is located in the suprachiasmatic nuclei (SCN) of the hypothalamus and it regulates circadian oscillators in tissues throughout the body t ... Full text Cite

Modulation of recognition memory performance by light requires both melanopsin and classical photoreceptors.

Journal Article Proceedings. Biological sciences · December 2016 Acute light exposure exerts various effects on physiology and behaviour. Although the effects of light on brain network activity in humans are well demonstrated, the effects of light on cognitive performance are inconclusive, with the size, as well as dire ... Full text Cite

Melanopsin Regulates Both Sleep-Promoting and Arousal-Promoting Responses to Light.

Journal Article PLoS biology · June 2016 Light plays a critical role in the regulation of numerous aspects of physiology and behaviour, including the entrainment of circadian rhythms and the regulation of sleep. These responses involve melanopsin (OPN4)-expressing photosensitive retinal ganglion ... Full text Cite

d-amino acid oxidase knockout (Dao(-/-) ) mice show enhanced short-term memory performance and heightened anxiety, but no sleep or circadian rhythm disruption.

Journal Article The European journal of neuroscience · May 2015 d-amino acid oxidase (DAO, DAAO) is an enzyme that degrades d-serine, the primary endogenous co-agonist of the synaptic N-methyl-d-aspartate receptor. Convergent evidence implicates DAO in the pathophysiology and potential treatment of schizophrenia. To be ... Full text Cite

Effects of dorsal hippocampal damage on conditioning and conditioned-response timing: A pooled analysis.

Journal Article Hippocampus · April 2015 Behavioral findings suggest that the dorsal hippocampus (DHPC) plays a role in timing of appetitive conditioned responding. The present article explored the relationship between the extent of DHPC damage and timing ability, in a pooled analysis of three pu ... Full text Cite

Relative recency influences object-in-context memory.

Journal Article Behavioural brain research · March 2015 In two experiments rats received training on an object-in-context (OIC) task, in which they received preexposure to object A in context x, followed by exposure to object B in context y. In a subsequent test both A and B are presented in either context x or ... Full text Cite

Timing and Conditioning, Theoretical Issues

Chapter · January 1, 2015 In a typical conditioning task, a conditioned stimulus (CS) is reliably followed by an outcome of motivational value. As a result, a conditioned response (CR) develops during the CS, indicating anticipation of the unconditioned stimulus (US). This chapter ... Full text Cite

Deletion of Metabotropic Glutamate Receptors 2 and 3 (mGlu2 & mGlu3) in Mice Disrupts Sleep and Wheel-Running Activity, and Increases the Sensitivity of the Circadian System to Light.

Journal Article PloS one · January 2015 Sleep and/or circadian rhythm disruption (SCRD) is seen in up to 80% of schizophrenia patients. The co-morbidity of schizophrenia and SCRD may in part stem from dysfunction in common brain mechanisms, which include the glutamate system, and in particular, ... Full text Cite

Sleep and circadian rhythm disruption and recognition memory in schizophrenia.

Chapter · January 2015 Schizophrenia patients often show irregularities in sleep and circadian rhythms and deficits in recognition memory. Similar phenotypes are seen in schizophrenia-relevant genetic mouse models, such as synaptosomal associated protein of 25 kDa (Snap-25) poin ... Full text Cite

Dissociations in the effect of delay on object recognition: evidence for an associative model of recognition memory.

Journal Article Journal of experimental psychology. Animal learning and cognition · January 2014 Rats were administered 3 versions of an object recognition task: In the spontaneous object recognition task (SOR) animals discriminated between a familiar object and a novel object; in the temporal order task they discriminated between 2 familiar objects, ... Full text Cite

Enhanced unblocking from sustained post-trial surprise.

Journal Article Journal of experimental psychology. Animal behavior processes · October 2013 Two appetitive conditioning experiments with rats investigated the mechanisms and properties of unblocking that results from the surprising omission of an expected post-trial unconditioned stimulus (US). Experiment 1 demonstrated unblocking under circumsta ... Full text Cite

Dorsal hippocampal involvement in conditioned-response timing and maintenance of temporal information in the absence of the CS.

Journal Article Experimental brain research · June 2013 Involvement of the dorsal hippocampus (DHPC) in conditioned-response timing and maintaining temporal information across time gaps was examined in an appetitive Pavlovian conditioning task, in which rats with sham and DHPC lesions were first conditioned to ... Full text Cite

Dorsal hippocampal involvement in appetitive trace conditioning and interval timing.

Journal Article Behavioral neuroscience · April 2012 Involvement of the dorsal hippocampus (DHPC) in acquisition of Pavlovian trace conditioning and interval timing was examined in an appetitive preparation in which presentations of one conditioned stimulus (CS) were immediately followed by food (delay condi ... Full text Cite

Dorsal hippocampal lesions disrupt Pavlovian delay conditioning and conditioned-response timing.

Journal Article Behavioural brain research · April 2012 The involvement of the rat dorsal hippocampus (dhpc) in Pavlovian conditioning and timing of conditioned responding was examined in an appetitive preparation in which presentation of a relatively long, 40-s auditory conditioned stimulus (CS) was followed i ... Full text Cite