Social context modulates autonomic responses to direct eye contact.

Eye contact with another person (social gaze) can evoke emotions, produce autonomic arousal, and influence behavior. Gaze cues can be evocative even when presented in static pictures of faces suggesting that responses depend on low-level visual features of gaze stimuli. The current study examined whether emotional gaze responses depend on the physical stimulus properties of an eye contact experience versus the cognitive evaluation of the social context of gaze.

In vivo tracking of KCC2b expression during early brain development.

The neuronal chloride (Cl-) exporter, KCC2, regulates neuron excitability and development and undergoes a stereotypical pattern of delayed upregulation as neurons mature. KCC2 upregulation favors neural inhibition by establishing a negative Cl- gradient, ensuring GABA-induced Cl- currents are inward and inhibitory. We developed a zebrafish fluorescent reporter line, KCC2b:mCitrine, to track KCC2 expression in vivo during early brain development.

Three-dimensional motion tracking reveals a diving component to visual and auditory escape swims in zebrafish larvae.

Escape behaviors have been studied in zebrafish by neuroscientists seeking cellular-level descriptions of neural circuits but few studies have examined vertical swimming during escapes. We analyzed three-dimensional swimming paths of zebrafish larvae during visually-evoked and auditory-evoked escapes while the fish were in a cubical tank with equal vertical and lateral range. Visually evoked escapes, elicited by sudden dimming of ambient light, consistently elicited downward spiral swimming (dives) with faster vertical than lateral movement.

Selective toxicity of L-DOPA to dopamine transporter-expressing neurons and locomotor behavior in zebrafish larvae.

Dopamine signaling is conserved across all animal species and has been implicated in the disease process of many neurological disorders, including Parkinson's disease (PD). The primary neuropathology in PD involves the death of dopaminergic cells in the substantia nigra (SN), an anatomical region of the brain implicated in dopamine production and voluntary motor control. Increasing evidence suggests that the neurotransmitter dopamine may have a neurotoxic metabolic product (DOPAL) that selectively damages dopaminergic cells.

Physiological stress reactivity and empathy following social exclusion: a test of the defensive emotional analgesia hypothesis.

Experiences of social exclusion elicit social pain responses. The current study examined the ability of social exclusion to activate physiological stress responses and adaptively modulate affect and empathy consistent with "defensive emotional analgesia." Measures of affect and empathy, and saliva samples for cortisol and alpha-amylase (sAA) analysis, were collected before and after subjects participated in a computer game ("Cyberball") designed to manipulate feelings of social exclusion.

Graph theoretical model of a sensorimotor connectome in zebrafish.

Mapping the detailed connectivity patterns (connectomes) of neural circuits is a central goal of neuroscience. The best quantitative approach to analyzing connectome data is still unclear but graph theory has been used with success. We present a graph theoretical model of the posterior lateral line sensorimotor pathway in zebrafish.

Lipopolysaccharide-induced immune activation impairs attention but has little effect on short-term working memory.

Cytokine-induced CNS inflammation has been theorized to contribute to cognitive dysfunction in sickness and neurodegenerative disease. We investigated the effects of systemic endotoxin-induced acute immune activation and inflammation on working memory and attention functions in pigeons assessed through two variations of an operant symbolic matching-to-sample (SMTS) task, employing doses of lipopolysaccharide (LPS) sufficient to induce fever. LPS produced moderate impairments in comparison to saline on the SMTS task designed to measure visual vigilance and attention, but the impairments were not as marked as those produced by chlordiazepoxide (CDP) which is known to disrupt attention.

Forward genetic analysis of visual behavior in zebrafish.

The visual system converts the distribution and wavelengths of photons entering the eye into patterns of neuronal activity, which then drive motor and endocrine behavioral responses. The gene products important for visual processing by a living and behaving vertebrate animal have not been identified in an unbiased fashion. Likewise, the genes that affect development of the nervous system to shape visual function later in life are largely unknown.

Visual prey capture in larval zebrafish is controlled by identified reticulospinal neurons downstream of the tectum.

Many vertebrates are efficient hunters and recognize their prey by innate neural mechanisms. During prey capture, the internal representation of the prey's location must be constantly updated and made available to premotor neurons that convey the information to spinal motor circuits. We studied the neural substrate of this specialized visuomotor system using high-speed video recordings of larval zebrafish and laser ablations of candidate brain structures.

Of lasers, mutants, and see-through brains: functional neuroanatomy in zebrafish.

Behavioral functions are carried out by localized circuits in the brain. Although this modular principle is clearly established, the boundaries of modules, and sometimes even their existence, are still debated. Zebrafish might offer distinct advantages in localizing behaviors to discrete brain regions because of the ability to visualize, record from, and lesion precisely identified populations of neurons in the brain.

Probing neural circuits in the zebrafish: a suite of optical techniques.

The ability to image neural activity in populations of neurons inside an intact animal, while obtaining single-cell or subcellular spatial resolution, has led to several advances in our understanding of vertebrate locomotor control. This result, first reported in a 1995 study of motoneurons in larval zebrafish, was the beginning of a series of technical developments that exploited the transparency and simplicity of the larval CNS. Presented here, in chronological fashion, is a suite of imaging techniques that have extended the ability to probe and optically dissect neural control systems.

Visually guided injection of identified reticulospinal neurons in zebrafish: a survey of spinal arborization patterns.

We report here the pattern of axonal branching for 11 descending cell types in the larval brainstem; eight of these cell types are individually identified neurons. Large numbers of brainstem neurons were retrogradely labeled in living larvae by injecting Texas-red dextran into caudal spinal cord. Subsequently, in each larva a single identified cell was injected in vivo with Alexa 488 dextran, using fluorescence microscopy to guide the injection pipette to the targeted cell.

Evidence for a widespread brain stem escape network in larval zebrafish.

Zebrafish escape behaviors, which typically consist of a C bend, a counter-turn, and a bout of rapid swimming, are initiated by firing of the Mauthner cell and two segmental homologs. However, after laser-ablation of the Mauthner cell and its homologs, escape-like behaviors still occur, albeit at a much longer latency. This might suggest that additional neurons contribute to this behavior.