Visions of vision: Studies of the horseshoe crab compound eye

1992 ◽  
Vol 50 (1) ◽  
pp. 488-489
Author(s):  
Steven C. Chamberlain
Keyword(s):  
Horseshoe Crab ◽  
Light Adaptation ◽  
Compound Eye ◽  
Visually Guided ◽  
Morphological Process ◽  
Morphological Studies ◽  
Visual Processes ◽  
Lateral Eye ◽  
The Brain

The lateral eye of the horseshoe crab, Limulus polyphemus, is an important model system for studies of visual processes such as phototransduction, lateral inhibition, and light adaptation. It has also been the system of choice for pioneering studies of the role of circadian efferent input from the brain to the eye. For example, light and efferent input interact in controlling the daily shedding of photosensitive membrane and photomechanical movements. Most recently, modeling efforts have begun to relate anatomy, physiology and visually guided behavior using parallel computing. My laboratory has pursued collaborative morphological studies of the compound eye for the past 15 years. Some of this research has been correlated structure/function studies; the rest has been studies of basic morphology and morphological process.

Histochemical localization of acetylcholinesterase in the lateral eye and brain of Limulus polyphemus: Might acetylcholine be a neurotransmitter for lateral inhibition in the lateral eye?

1994 ◽  
Vol 11 (5) ◽  
pp. 989-1001 ◽  
Author(s):  
Eric P. Hornstein ◽  
Daniel L. Sambursky ◽  
Steven C. Chamberlain
Keyword(s):  
Optic Nerve ◽  
Lateral Inhibition ◽  
Horseshoe Crab ◽  
Compound Eye ◽  
Nerve Fibers ◽  
Intense Staining ◽  
Histaminergic Neurons ◽  
Lateral Eye ◽  
Weak Staining ◽  
The Brain

AbstractThe distribution of acetylcholinesterase (AChE) in the lateral eye and brain of the horseshoe crab was investigated with histochemical means using standard controls to eliminate butyrylcholinesterase and nonspecific staining. Intense staining was observed in the neural plexus of the lateral compound eye, in the lateral optic nerve, and in various neuropils of the brain. Nerve fibers with moderate to weak staining were widespread in the brain. No sornata were stained in either the lateral eye or the brain. The distribution of acetylcholinesterase in the supraesophageal ganglia and nerves of the giant barnacle was also investigated for comparison. Although both the median optic nerve of the barnacle and the lateral optic nerve of the horseshoe crab appear to contain the fibers of histaminergic neurons, only the lateral optic nerve of the horseshoe crab shows AChE staining. Other parts of the barnacle nervous system, however, showed intense AChE staining. These results along with the histochemical controls eliminate the possibility that some molecule found in histaminergic neurons accounted for the AChE staining but support the possibility that acetylcholine might be involved as a neurotransmitter in lateral inhibition in the horseshoe crab retina. Two reasonable neurotransmitter candidates for lateral inhibition, histamine and acetylcholine, must now be investigated.

The Brain Doesn’t Work by Logic

2018 ◽  
Author(s):  
James A. Anderson
Keyword(s):  
Lateral Inhibition ◽  
Horseshoe Crab ◽  
Compound Eye ◽  
Visual Image ◽  
Neural Computation ◽  
Single Neurons ◽  
Moving Image ◽  
Cortical Areas ◽  
Lateral Eye ◽  
The Brain

This chapter gives three examples of real neural computation. The conclusion is that the “brain doesn’t work by logic.” First, is the Limulus (horseshoe crab) lateral eye. The neural process of “lateral inhibition” tunes the neural response of the compound eye to allow crabs to better see other crabs for mating. Second, the retina of the frog contains cells that are selective to specific properties of the visual image. The frog responds strongly to the moving image of a bug with one class of selective retinal receptors. Third, experiments on patients undergoing neurosurgery for epilepsy found single neurons in several cortical areas that were highly selective to differing images, text strings, and spoken names of well-known people. In addition, new selective responses could be formed quickly. The connection to concepts in cognitive science seems inevitable. One possible mechanism is through associatively linked “cell assemblies.”

scholarly journals Electroretinogram Characteristics and the Spectral Mechanisms of the Median Ocellus and the Lateral Eye in Limulus polyphemus

1967 ◽  
Vol 50 (9) ◽  
pp. 2267-2287 ◽  
Author(s):  
Robert M. Chapman ◽  
Abner B. Lall
Keyword(s):  
Spectral Sensitivity ◽  
Visual Pigment ◽  
Light Adaptation ◽  
Compound Eye ◽  
State Level ◽  
Chromatic Adaptation ◽  
Absorption Bands ◽  
Energy Functions ◽  
Lateral Eye ◽  
Median Ocellus

Electrical responses (ERG) to light flashes of various wavelengths and energies were obtained from the dorsal median ocellus and lateral compound eye of Limulus under dark and chromatic light adaptation. Spectral mechanisms were studied by analyzing (a) response waveforms, e.g. response area, rise, and fall times as functions of amplitude, (b) slopes of amplitude-energy functions, and (c) spectral sensitivity functions obtained by the criterion amplitude method. The data for a single spectral mechanism in the lateral eye are (a) response waveforms independent of wavelength, (b) same slope for response-energy functions at all wavelengths, (c) a spectral sensitivity function with a single maximum near 520 mµ, and (d) spectral sensitivity invariance in chromatic adaptation experiments. The data for two spectral mechanisms in the median ocellus are (a) two waveform characteristics depending on wavelength, (b) slopes of response-energy functions steeper for short than for long wavelengths, (c) two spectral sensitivity peaks (360 and 530–535 mµ) when dark-adapted, and (d) selective depression of either spectral sensitivity peak by appropriate chromatic adaptation. The ocellus is 200–320 times more sensitive to UV than to visible light. Both UV and green spectral sensitivity curves agree with Dartnall's nomogram. The hypothesis is favored that the ocellus contains two visual pigments each in a different type of receptor, rather than (a) various absorption bands of a single visual pigment, (b) single visual pigment and a chromatic mask, or (c) fluorescence. With long duration light stimuli a steady-state level followed the transient peak in the ERG from both types of eyes.

scholarly journals Effect of Viewing Distance On Object Responses In Macaque Areas 45B, F5a And F5p

2021 ◽  
Author(s):  
Irene Caprara ◽  
Peter Janssen
Keyword(s):  
Visual Representation ◽  
Motor Command ◽  
Peripersonal Space ◽  
Visual Object ◽  
Viewing Distance ◽  
Visually Guided ◽  
Grip Aperture ◽  
Object Processing ◽  
The Brain

Abstract To perform tasks like grasping, the brain has to process visual object information so that the grip aperture can be adjusted before touching the object. Previous studies have demonstrated that the posterior subsector of the Anterior Intraparietal area (pAIP) is connected to area 45B, and its anterior counterpart (aAIP) to F5a. However, the role of area 45B and F5a in visually-guided grasping is poorly understood. Here, we investigated the role of area 45B, F5a and F5p in object processing during visually-guided grasping in two monkeys. If the presentation of an object activates a motor command related to the preshaping of the hand, as in F5p, such neurons should prefer objects presented within reachable distance. Conversely, neurons encoding a purely visual representation of an object – possibly in area 45B and F5a – should be less affected by viewing distance. Contrary to our expectations, we found that most neurons in area 45B were object- and viewing distance-selective (mostly Near-preferring). Area F5a showed much weaker object selectivity compared to 45B, with a similar preference for objects presented at the Near position. Finally, F5p neurons were less object selective and frequently Far-preferring. In sum, area 45B – but not F5p– prefers objects presented in peripersonal space.

scholarly journals Neuroplasticity and Multilevel System of Connections Determine the Integrative Role of Nucleus Accumbens in the Brain Reward System

2021 ◽  
Vol 22 (18) ◽  
pp. 9806
Author(s):  
Martyna Bayassi-Jakowicka ◽  
Grazyna Lietzau ◽  
Ewelina Czuba ◽  
Aleksandra Steliga ◽  
Monika Waśkow ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Complex Function ◽  
Reward System ◽  
Neurotransmitter Systems ◽  
Morphological Studies ◽  
Starting Point ◽  
Brain Reward ◽  
The Brain ◽  
Brain Reward System

A growing body of evidence suggests that nucleus accumbens (NAc) plays a significant role not only in the physiological processes associated with reward and satisfaction but also in many diseases of the central nervous system. Summary of the current state of knowledge on the morphological and functional basis of such a diverse function of this structure may be a good starting point for further basic and clinical research. The NAc is a part of the brain reward system (BRS) characterized by multilevel organization, extensive connections, and several neurotransmitter systems. The unique role of NAc in the BRS is a result of: (1) hierarchical connections with the other brain areas, (2) a well-developed morphological and functional plasticity regulating short- and long-term synaptic potentiation and signalling pathways, (3) cooperation among several neurotransmitter systems, and (4) a supportive role of neuroglia involved in both physiological and pathological processes. Understanding the complex function of NAc is possible by combining the results of morphological studies with molecular, genetic, and behavioral data. In this review, we present the current views on the NAc function in physiological conditions, emphasizing the role of its connections, neuroplasticity processes, and neurotransmitter systems.

scholarly journals Role of Serotonin Transporter in Eye Development of Drosophila melanogaster

2020 ◽  
Vol 21 (11) ◽  
pp. 4086
Author(s):  
Tuan L. A. Pham ◽  
Tran Duy Binh ◽  
Guanchen Liu ◽  
Thanh Q. C. Nguyen ◽  
Yen D. H. Nguyen ◽  
...  
Keyword(s):  
Cell Death ◽  
Drosophila Melanogaster ◽  
Serotonin Transporter ◽  
Compound Eye ◽  
Eye Development ◽  
S Phase ◽  
Eye Disc ◽  
Eye Imaginal Disc ◽  
The Brain

Serotonin transporter (SerT) in the brain is an important neurotransmitter transporter involved in mental health. However, its role in peripheral organs is poorly understood. In this study, we investigated the function of SerT in the development of the compound eye in Drosophila melanogaster. We found that SerT knockdown led to excessive cell death and an increased number of cells in S-phase in the posterior eye imaginal disc. Furthermore, the knockdown of SerT in the eye disc suppressed the activation of Akt, and the introduction of PI3K effectively rescued this phenotype. These results suggested that SerT plays a role in the healthy eye development of D. melanogaster by controlling cell death through the regulation of the PI3K/Akt pathway.

scholarly journals Feedback Network Controls Photoreceptor Output at the Layer of First Visual Synapses in Drosophila

2006 ◽  
Vol 127 (5) ◽  
pp. 495-510 ◽  
Author(s):  
Lei Zheng ◽  
Gonzalo G. de Polavieja ◽  
Verena Wolfram ◽  
Musa H. Asyali ◽  
Roger C. Hardie ◽  
...  
Keyword(s):  
Compound Eye ◽  
Amacrine Cells ◽  
Feedback Network ◽  
Coding Strategies ◽  
Neural Information ◽  
Neural Information Processing ◽  
Light Stimuli ◽  
The Brain

At the layer of first visual synapses, information from photoreceptors is processed and transmitted towards the brain. In fly compound eye, output from photoreceptors (R1–R6) that share the same visual field is pooled and transmitted via histaminergic synapses to two classes of interneuron, large monopolar cells (LMCs) and amacrine cells (ACs). The interneurons also feed back to photoreceptor terminals via numerous ligand-gated synapses, yet the significance of these connections has remained a mystery. We investigated the role of feedback synapses by comparing intracellular responses of photoreceptors and LMCs in wild-type Drosophila and in synaptic mutants, to light and current pulses and to naturalistic light stimuli. The recordings were further subjected to rigorous statistical and information-theoretical analysis. We show that the feedback synapses form a negative feedback loop that controls the speed and amplitude of photoreceptor responses and hence the quality of the transmitted signals. These results highlight the benefits of feedback synapses for neural information processing, and suggest that similar coding strategies could be used in other nervous systems.

Photoreceptor cells dissociated from the compound lateral eye of the horseshoe crab, Limulus polyphemus, II: Function

1993 ◽  
Vol 10 (4) ◽  
pp. 609-620 ◽  
Author(s):  
W. J. Brad Hanna ◽  
Edwin C. Johnson ◽  
Deborah Chaves ◽  
George H. Renninger
Keyword(s):  
Horseshoe Crab ◽  
Compound Eye ◽  
Light Response ◽  
Photoreceptor Cells ◽  
Limulus Polyphemus ◽  
Isolated Cells ◽  
Lateral Eye ◽  
Small Clusters ◽  
Invertebrate Photoreceptor

AbstractA combination of enzymatic digestions and mechanical disruption was used to isolate photoreceptor cells from the compound lateral eye of the horseshoe crab, Limulus polyphemus. The cells were maintained in a culture medium and tested for function using whole-cell and cell-attached patch configurations of the gigaseal technique. The cells dissociated from the eye generated spontaneous voltage and current bumps in the dark, and depolarized in a graded fashion to increasing intensities of light over several decades, producing responses similar to those of cells in vivo. Currents evoked during voltage clamp were similar to those in ventral photoreceptor cells of Limulus, although transient currents in the dark- and light-activated currents were smaller in isolated lateral eye cells, perhaps because of the slow speed and spatial nonuniformity of the clamp in these large cells. In addition to isolated cells, dissociation of the compound eye produced small clusters of cells and isolated ommatidia which were also tested for function. Comparison of the electrical characteristics of isolated cells with those of cells in small clusters and in their ommatidial matrix suggests that the electrical junctions normally connecting photoreceptor cells within an ommatidium are functional in the latter groups, but not in isolated cells. Cell-attached patches of rhabdomeral membrane of isolated cells contained light-activated channels, resembling those observed in ventral photoreceptor cells, but no voltage-activated channels. Similar patches of arhabdomeral membrane contained voltage-activated channels, but no light-activated channels. We conclude that this preparation is suitable for studies of processes involved in generating the light response in invertebrate photoreceptor cells.

Localization of actin filaments and microtubules in the cells of the Limulus lateral and ventral eyes

1992 ◽  
Vol 9 (3-4) ◽  
pp. 365-375 ◽  
Author(s):  
Bruce G. Calman ◽  
Steven C. Chamberlain
Keyword(s):  
Neural Activity ◽  
Actin Filaments ◽  
Horseshoe Crab ◽  
Cell Dendrite ◽  
Cell Cytoplasm ◽  
Retinular Cell ◽  
Lateral Eye ◽  
Cone Cells ◽  
Cytoskeletal Elements ◽  
The Brain

AbstractThe ommatidia of the lateral eye of the horseshoe crab, Limulus polyphemus, undergo rhythmic changes in structure that are driven by diurnal lighting and efferent neural activity from a circadian clock in the brain. This study uses cytochemical probes to investigate the cytoskeletal elements mediating these responses and to develop models for their control. Antibodies to actin and phalloidin, a specific F-actin probe, label the rhabdom of lateral eye ommatidia, the cone cells of the ommatidial aperture, the ommatidial sheath, and the peripheral regions of the photoreceptor (retinular cell) cytoplasm. These probes also label the rhabdomere of ventral photoreceptors. Antibodies to tubulin label the eccentric cell dendrite and soma in each lateral eye ommatidium, the cone cells of the aperture, and the peripheral retinular cell cytoplasm. Models are proposed for the cytoskeletal mechanisms involved in controlling aperture and rhabdom shape, pigment movement, and shedding of rhabdomeral membrane.

Visual Efference Neuromodulates Retinal Timing: In Vivo Roles of Octopamine, Substance P, Circadian Phase, and Efferent Activation in Limulus

2009 ◽  
Vol 102 (2) ◽  
pp. 1132-1138 ◽  
Author(s):  
Amanda R. Bolbecker ◽  
Corrinne C. M. Lim-Kessler ◽  
Jia Li ◽  
Alicia Swan ◽  
Adrienne Lewis ◽  
...  
Keyword(s):  
Substance P ◽  
Horseshoe Crab ◽  
Response Duration ◽  
Circadian Phase ◽  
Lateral Eye ◽  
Response Onset ◽  
Timing Effects ◽  
The Brain

Efferent nerves coursing from the brain to the lateral eye of the horseshoe crab, Limulus polyphemus, increase its nighttime sensitivity to light. They release octopamine, which produces a categorical increase of photoreceptor response duration in vitro. Analogous in vivo timing effects on the electroretinogram (ERG) were demonstrated when octopamine was infiltrated into the eye of an otherwise intact animal; nighttime ERGs were longer than daytime ERGs. Related effects on the ERG were produced by daytime electrical stimulation of efferent fibers. Surprisingly, in a departure from effects predicted solely from in vitro octopamine data, nighttime ERG onsets were also accelerated relative to daytime ERG onsets. Drawing on earlier reports, these remarkable accelerations led to an examination of substance P as another candidate neuromodulator. It demonstrated that infiltrations of either modulator into the lateral eyes of otherwise intact crabs increased the amplitude of ERG responses but that each candidate modulator induced daytime responses that specifically mimicked one of the two particular aspects of the timing differences between day- and nighttime ERGs: octopamine increased the duration of daytime ERGs and substance P infiltrated during the day accelerated response onset. These results indicate that, in addition to octopamine's known role as an efferent neuromodulator that increases nighttime ERG amplitudes, octopamine clearly also affects the timing of photoreceptor responses. But these infiltration data go further and strongly suggest that substance P may also be released into the lateral eye at night, thereby accelerating the ERG's onset in addition to increasing its amplitude.

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