Defense reflex and motion detector responsiveness to approaching targets: The motion detector trigger to the defense reflex pathway

Glantz, Raymon M.

doi:10.1007/bf00609703

Cited by 52 publications

(37 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In agreement with our present results in N. granulata, studies in other crustaceans have shown that the decision is made based on an increase in the apparent size of the stimulus. For instance, the critical stimulus parameter to initiate the escape run in the crab Heloecius was found to be an increase of 5.6deg (see Hemmi, 2005b), whereas in the crayfish the required increase was 8deg (Glantz, 1974). In a previous study using a single looming stimulus, we reported that N. (Chasmagnathus) granulata started the escape when the angular size of the stimulus had grown by approximately 10deg , which is 3deg above the angular increment reported here.…”

Section: The Decision To Initiate the Escape Runmentioning

confidence: 46%

“…The first types of responses, which can be described as single threshold response systems, are triggered when an optical variable of the image exceeds a certain value, after which the animal displays a stereotyped behavior. This type of response has been described in species such as crayfish (Glantz, 1974) and fish (Preuss et al, 2006). In other cases, the avoidance response is composed of distinctive preparatory stages, each one being triggered when an optical variable reaches a particular threshold.…”

Section: Introductionmentioning

confidence: 89%

“…The crayfish defensive reflex occurs when the angular size of the approaching object increases by 8deg (Glantz, 1974).…”

Section: Angular Incrementmentioning

confidence: 99%

See 2 more Smart Citations

Visuo-motor transformations involved in the escape response to looming stimuli in the crab Neohelice (=Chasmagnathus) granulata

Oliva

Tomsic

2012

Journal of Experimental Biology

View full text Add to dashboard Cite

SUMMARYEscape responses to directly approaching predators represent one instance of an animalʼs ability to avoid collision. Usually, such responses can be easily evoked in the laboratory using two-dimensional computer simulations of approaching objects, known as looming stimuli. Therefore, escape behaviors are considered useful models for the study of computations performed by the brain to efficiently transform visual information into organized motor patterns. The escape response of the crab Neohelice (previously Chasmagnathus) granulata offers an opportunity to investigate the processing of looming stimuli and its transformation into complex motor patterns. Here we studied the escape performance of this crab to a variety of different looming stimuli. The response always consisted of a vigorous run away from the stimulus. However, the moment at which it was initiated, as well as the developed speed, closely matched the expansion dynamics of each particular stimulus. Thus, we analyzed the response events as a function of several variables that could theoretically be used by the crab (angular size, angular velocity, etc.). Our main findings were that: (1) the decision to initiate the escape run is made when the stimulus angular size increases by 7deg; (2) the escape run is not a ballistic kind of response, as its speed is adjusted concurrently with changes in the optical stimulus variables; and (3) the speed of the escape run can be faithfully described by a phenomenological input-output relationship based on the stimulus angular increment and the angular velocity of the stimulus.

show abstract

Section: The Decision To Initiate the Escape Runmentioning

confidence: 46%

Section: Introductionmentioning

confidence: 89%

See 1 more Smart Citation

Visuo-motor transformations involved in the escape response to looming stimuli in the crab Neohelice (=Chasmagnathus) granulata

Oliva

Tomsic

2012

Journal of Experimental Biology

View full text Add to dashboard Cite

show abstract

“…Some VGCABs can be described as all-or-none responses initiated when an optical variable surpasses a certain threshold value. This category of VGCAB was found in the crayfish defensive reflex (Glantz, 1974) and in flies (Borst and Bahde, 1988;Tammero and Dickinson, 2002). Other VGCABs include multiple response components, each one being launched when an optical variable attains a specific threshold.…”

Section: Introductionmentioning

confidence: 91%

“…Such neurons are commonly referred as looming sensitive neurons (LSNs). LSNs have been found in pigeons (Wang and Frost, 1992), fish (Preuss et al, 2006), monkeys (Maier et al, 2004) and different arthropod species such as locusts (Rind and Simmons, 1992;Gabbiani et al, 1999;Gray et al, 2010), flies (Borst, 1991;Fotowat et al, 2009), crayfish (Glantz, 1974) and crabs Oliva and Tomsic, 2014). But, how is the visual information of an approaching object actually processed, encoded and conveyed by LSNs to contribute to avoidance behaviors?…”

Section: Introductionmentioning

confidence: 99%

Object approach computation by a giant neuron and its relation with the speed of escape in the crab Neohelice

Oliva

Tomsic

2016

Journal of Experimental Biology

View full text Add to dashboard Cite

Upon detection of an approaching object, the crab Neohelice granulata continuously regulates the direction and speed of escape according to ongoing visual information. These visuomotor transformations are thought to be largely accounted for by a small number of motion-sensitive giant neurons projecting from the lobula (third optic neuropil) towards the supraesophageal ganglion. One of these elements, the monostratified lobula giant neuron of type 2 (MLG2), proved to be highly sensitive to looming stimuli (a 2D representation of an object approach). By performing in vivo intracellular recordings, we assessed the response of the MLG2 neuron to a variety of looming stimuli representing objects of different sizes and velocities of approach. This allowed us to: (1) identify some of the physiological mechanisms involved in the regulation of the MLG2 activity and test a simplified biophysical model of its response to looming stimuli; (2) identify the stimulus optical parameters encoded by the MLG2 and formulate a phenomenological model able to predict the temporal course of the neural firing responses to all looming stimuli; and (3) incorporate the MLG2-encoded information of the stimulus (in terms of firing rate) into a mathematical model able to fit the speed of the escape run of the animal. The agreement between the model predictions and the actual escape speed measured on a treadmill for all tested stimuli strengthens our interpretation of the computations performed by the MLG2 and of the involvement of this neuron in the regulation of the animal's speed of run while escaping from objects approaching with constant speed.

show abstract

Organization and significance of neurons that detect change of visual depth in the hawk mothManduca sexta

Wicklein

Strausfeld

2000

J. Comp. Neurol.

View full text Add to dashboard Cite

Visual stimuli representing looming or receding objects can be decomposed into four parameters: change in luminance; increase or decrease of area; increase or decrease of object perimeter length; and motion of the object's perimeter or edge. This paper describes intracellular recordings from visual neurons in the optic lobes of Manduca sexta that are selectively activated by certain of these parameters. Two classes of wide-field neurons have been identified that respond selectively to looming and receding stimuli. Class 1 cells respond to parameters of the image other than motion stimuli. They discriminate an approaching or receding disc from an outwardly or inwardly rotating spiral, being activated only by the disc and not by the spiral. Class 2 neurons respond to moving edges. They respond both to movement of the spiral and to an approaching or receding disc. These two classes are further subdivided into neurons that are excited by image expansion (looming) and are inhibited by image contraction (antilooming). Class 2 neurons also respond to horizontal and vertical movement of gratings over the retina. Stimulating class 1 and 2 neurons with white discs against a dark background results in the same activation as stimulation with dark discs against a white background, demonstrating that changes in luminance play no role in the detection of looming or antilooming. The present results show that the two types of looming-sensitive neurons in M. sexta use different mechanisms to detect the approach or retreat of an object. It is proposed that cardinal parameters for this are change of perimeter length detected by class 1 neurons and expansion or contraction visual flow fields detected by class 2 neurons. These two classes also differ with respect to their polarity, the former comprising centripetal cells from the optic lobes to the midbrain, the latter comprising centrifugal neurons from the midbrain to the optic lobes. The significance of these arrangements with respect to hovering flight is discussed.

show abstract

Defense reflex and motion detector responsiveness to approaching targets: The motion detector trigger to the defense reflex pathway

Cited by 52 publications

References 12 publications

Visuo-motor transformations involved in the escape response to looming stimuli in the crab Neohelice (=Chasmagnathus) granulata

Visuo-motor transformations involved in the escape response to looming stimuli in the crab Neohelice (=Chasmagnathus) granulata

Object approach computation by a giant neuron and its relation with the speed of escape in the crab Neohelice

Organization and significance of neurons that detect change of visual depth in the hawk mothManduca sexta

Contact Info

Product

Resources

About