We are searching data for your request:
Upon completion, a link will appear to access the found materials.
In insects like the cockroach the brain is distributed, i.e. some parts lie in the head and some in the abdominal cavity. Which part is responsible for controlling locomotion?
Technically speaking, locomotion is actually not produced by the brain in cockroaches; there are neurological controllers in the legs themselves which produce locomotion even when contact with centralized nervous system is severed.
I include this for reference, because it was not explicitly stated in your question. However, I believe it was intended to be implied by the phrase "responsible for controlling." In other words, from my understanding, you're more interested in what section of the brain actually controls those actions in a normal cockroach.
From Central Nervous Control of Cockroach Walking by Charles R. Froutner, you can see even just in the abstract that the movements became spontaneous when the connection with the segmental ganglion was broken, showing that this is very likely where the control is exerted. (The segmental ganglion, for reference, is a part of the dorsal "brain" you made reference to.)
Just to be clear, the brain is not distributed, it is the thoracic ganglia present in thorax that aid an arthropod for different tasks.
Arthropods have most of their sensory stimuli and motor actions controlled by Midline Brain Neurophils, called Central Complex (CC)
Quoting Journal of Experimental Biology >>
Previous studies have also linked the CC to motor actions. Huber showed that stimulation within the CC enhances locomotor activity (Huber, 1960). More recently, electrophysiology studies showed that the neural activity of some CC units is correlated with, and often precedes, changes in stepping frequency.
Blood Vascular System: The blood vascular system is an open type. Blood vessels are poorly developed. They open into space (haemocoel). Visceral organs located in the haemocoel are bathed in blood (haemolymph). The haemolymph is composed of colourless plasma and haemocytes. The heart consists of elongated muscular tubes which lie along mid-dorsal line of thorax and abdomen. The heart is differentiated into funnel-shaped chambers with ostia on either side. The blood from sinuses enters the heart through ostia and is pumped anteriorly to the sinuses again.
Respiratory System: The respiratory system consists of a network of trachea. The tracheae open through 10 pairs of small holes called spiracles. The spiracles are present on the lateral side of the body. Tracheal tubes are subdivided into tracheoles. They carry oxygen to all the parts. The opening of the spiracles is regulated by sphincters. Exchange of gases takes place by diffusion.
Excretory System: Malpighian tubules are the excretory organs. Each tubule is lined by glandular and ciliated cells. They absorb nitrogenous wastes and convert them into uric acid. Uric acid is excreted out through the hindgut. Additionally, fat body, nephrocytes and urecose glands also help in excretion.
Nervous System: The nervous system of cockroach consists of a series of fused, segmentally arranged ganglia. The ganglia are joined by paired longitudinal connectives on the ventral side. Three ganglia lie in the thorax and six in the abdomen. The nervous system in cockroach is spread throughout the body. In the head region, the brain is represented by supra-oesophageal ganglion. It supplies nerves to antennae and compound eyes.
Sense Organs: Antennae, eyes, maxillary palps, labial palps, anal cerci, etc. are the sense organs in cockroach. The compound eyes are situated at the dorsal surface of head. Each eye consists of about 2000 hexagonal ommatidia. Presence of several ommatidia gives mosaic vision to the cockroach. This gives more sensitivity but less resolution. This type of vision is common during night.
Cockroaches are dioecious.
Male Reproductive System: The male reproductive system of cockroach consists of a pair of testes. The testes lie on each lateral side in the 4th – 6th abdominal segments. A thin vas deferens arises from each testis. It opens into ejaculatory duct through seminal vesicle. The ejaculatory duct opens into male gonopore which is situated ventral to anus. A typical mushroom-shaped gland is present in the 6th-7th abdominal segments. It is an accessory reproductive gland. Male gonapophysis or phallomeres represent the external genitalia. These are made up of chitin. They are asymmetrical structures and surround the male gonopore. The sperms are stored in the seminal vesicles. The sperms are glued together in the form of bundles called spermatophores. Spermatophores are discharged during copulation.
Female Reproductive System: The female reproductive system of cockroach consists of two large ovaries. The ovaries lie laterally in the 2nd – 6th abdominal segments. Each ovary is formed of a group of eight ovarian tubules or ovarioles. They contain a chain of developing ova. Oviducts from each ovary unite into a single median oviduct. This is also called vagina and it opens into the genital chamber. A pair of spermatheca is present in the 6th segment which opens into the genital chamber.
Fertilization: Sperms are transferred through spermatophores. The fertilized eggs are encased in capsules called ootheca. An ootheca is a dark reddish to blackish brown capsule. It is about 8 mm long. The oothecae are dropped or glued to a suitable surface usually at a place with high relative humidity or near a food source. On an average, 9 – 10 ootehcae are produced by a female. Each ootheca contains 14 – 16 eggs. Development is indirect and is paurometabolous. Development through nymph stage is called paurometabolous. The nymph resembles the adults. The nymph grows by moulting about 13 times to reach the adult form. Wing pads are seen in the penultimate stage of development but wings are present only in adults.
Significance for Human: Most of the species are wild and have no economic importance. Some species live in and around human habitat. They destroy food and contaminate food with their excreta. Many bacterial diseases can be transmitted by food contamination by cockroaches.
Neurons are the cells that transmit information in an animal's nervous system so that it can sense stimuli from its environment and behave accordingly. Not all animals have neurons Trichoplax and sponges lack nerve cells altogether.
Neurons may be packed to form structures such as the brain of vertebrates or the neural ganglions of insects.
The number of neurons and their relative abundance in different parts of the brain is a determinant of neural function and, consequently, of behavior.
All numbers for neurons (except Caenorhabditis and Ciona), and all numbers for synapses (except Ciona) are estimations.
The cerebral cortex is a structure of particular interest at the intersection between comparative neuroanatomy and comparative cognitive psychology. Historically, it had been assumed that since only mammals have a cerebral cortex, only they benefit from the information processing functions associated with it, notably awareness and thought.  It is now known that non-avian reptiles also have a cerebral cortex and that birds have a functional equivalent called the dorsal ventricular ridge (DVR), which in fact appears to be a modification subsequent to the reptilian cortex. A modern understanding of comparative neuroanatomy now suggests that for all vertebrates, the pallium roughly corresponds to this general sensory-associative structure.  It is also a widely accepted view that arthropods and closely related worms have an equivalent structure, the corpora pedunculata, more commonly known as mushroom bodies. In fact this structure in invertebrates and the pallium in vertebrates may have a common evolutionary origin from a common ancestor. 
Given the apparent function of the sensory-associative structure, it has been suggested that the total number of neurons in the pallium or its equivalents may be the best predictor of intelligence when comparing species, being more representative than total brain mass or volume, brain-to-body mass ratio, or encephalization quotient (EQ).  It may thus be reasonably assumed that the total number of neurons in an animal's corresponding sensory-associative structure strongly relates to its degree of awareness, breadth and variety of subjective experiences, and intelligence. 
The methods used to arrive at the numbers in this list include neuron count by isotropic fractionator, optical fractionator or estimation based on correlations observed between number of cortical neurons and brain mass within closely related taxa. Isotropic fractionation is often considered more straightforward and reliable than optical fractionation which may yield both overestimates and underestimates.  Estimation based on brain mass and taxon is to be considered the least reliable method.
Preparation for the RoboRoach Surgery
Are you ready to try your hand as a cockroach brain surgeon and make your very own temporary cyborg?
The surgery itself takes about 30-45 minutes. An important aspect for a good scientific surgery is proper preparation, thorough documentation, and consideration of the well-being of the animal.. So, considering both set-up and cleanup time, plan for at least an hour for the full operation. Anyone can do the RoboRoach surgery, but like everything in life, it takes practice and patience to master! That’s why your kit comes with 3 sets of electrode arrays, enough for you to prepare 3 RoboRoaches to learn and improve from repeating the experiment. Additional RoboRoach electrodes are available through our online store or you can take the DIY route and build your own electrodes. We recommend that you carefully read through this guided experiment entirely before you start the surgery to prepare your human brain as well!
Also, we’d like to remind you that the RoboRoach is an educational tool to be used with cockroaches to learn about neural interfaces. Please respect and abide by your presiding government’s laws and regulations when it comes to animal research. If you have ethical concerns or questions, please refer to our ethics guideline and discussion .
What you'll need:
- The "RoboRoach Surgery Procedure" (below). This is also available as a(n):
- Downloadable PDF.
- Instructional video.
- A printed "RoboRoach Surgery Worksheet"
- Your brain, some patience, and a deft hand
- Approximately 1 hour of your time
- 1 “RoboRoach Surgery Kit”
- 150 grit sandpaper
- Loctite Super Glue Gel Control (note: we’ve found this stuff works the best, other super glues may not substitute)
- Cotton swabs
- Silly putty
- Small-diameter needle
- Dissection scissors
- Tweezers or forceps
- Magnifying glass (or upgrade and impress your friends with a RoachScope)
- Low-temp hot glue gun & glue cylinders
- Popsicle stick
- Small amount of flour
- Cup of ice water (you’ll want enough ice to keep the water very cold but enough water to be able to submerge the roach). Ice water is always 32 degrees fahrenheit, so long as there is still ice in the water.
- Paper towels
- Clock with minutes hand
- Work lamp, don’t try this in the dark!
- 1 RoboRoach electrode array
- . and of course: 1 large, healthy adult Discoid cockroach. IMPORTANT: Adults can be identified by a black dot on the pronotum (the exoskeleton "hood" over their head) and the presence of wings. They will no longer molt. Therefore, affixing a connector to its head permanently is fine. NOTE: if you glue an electrode connector to a juvenile cockroach (no wings), it will not be able to split its exoskeleton when molting and will die. Do not do this surgery on juvenile cockroaches.
Amygdala dysfunction affects emotional processing, memory formation and storage, and conditional learning, and as such, it is associated with several neurodevelopmental and neurologic disorders as well as psychiatric conditions.
Post-Traumatic Stress Disorder (PTSD)
There is clear evidence of reduced amygdala volume and greater amygdala activation in patients with PTSD. This smaller size has been previously associated with side effects such as stronger fear conditioning and the stress response commonly associated with PTSD.
However, correlation is still unclear, suggesting either a smaller-volume amygdala is a potential risk factor for developing PTSD or a potential consequence of having PTSD.
While not an official treatment, amygdala neurofeedback has been suggested as potentially therapeutic for PTSD patients since it can help individuals enhance their ability to self-modulate brain activity.
Panic Disorder (PD)
Similar to its role in PTSD, some research suggests increased amygdala reactivity and volume deficit play a crucial role in other fear-based and anxiety-related pathologies, including panic attacks and panic disorder. Causes of amygdala abnormal functioning and structuring in PD patients have been linked to brain metabolism dysregulation, as well as genetic variation and early life trauma, and are associated with PD symptoms, including phobic avoidance and irrational worry of panic attacks.
Addiction relapse after abstinence happens in part due to drug exposure or exposure to people, places, and things that remind a person of the pleasurable and rewarding effects of drugs of addiction. Research shows this cognitive action of pairing a stimulus (drug) to a behavior (consumption) and desired emotional state is reminiscent of amygdala functioning.
While this means the amygdalae (and particularly the basolateral nucleus, or BLn) link drug intake to positive reward, it also means they link withdrawal or drug absence to negative emotions. The therapeutic potential of BLn-focused deep brain stimulation (DBS) in moderating these associations (and therefore helping reduce relapse likelihood) is being investigated.
Studies have shown sustained increased amygdala activity in depressed patients, so some researchers have suggested depression is likely the result of outer brain activity imbalance, which also impacts internal structures like the amygdala in a top-down mechanism. However, the opposite is also true for some patients, meaning abnormal activity in the amygdala can lead to imbalances in the outer brain.
Nevertheless, the amygdalae are responsible for assigning value to objects and activities, and their dysfunction could explain a depressed patient’s inability to assign positive value to objects and activities, including themselves. This could lead to lower self-esteem and general life dissatisfaction.
DBS treatment focusing on the amygdala offers potential, but again, more research is required.
Alzheimer’s Disease (AD)
Among the first areas of the brain damaged by Alzheimer’s disease are the hippocampus and its connected structures, including the amygdalae. The amygdalae are known to be affected in AD patients, with their volume and functionality decreasing with age and disease progression.
Effects of this can be seen in early stages of AD and are directly associated with communication disruption between the amygdala and hippocampus. Consequences result from declining cognitive abilities related to making new memories and learning new information, and degradation of emotional processing present in AD patients.
Studies conducted on mice, while not equivalent to human clinical trials, have shown stem cell regeneration in the amygdala, suggesting an avenue for further research that could impact the life course of those with amygdala damage due to AD.
Urbach-Wiethe Disease (UWD)
Urbach-Wiethe (lipoid proteinosis) is an extremely rare syndrome characterized by hoarse voice since birth and collagen deposits in the skin and soft tissues. More than half of UWD patients have amygdaloid region damage caused by selective calcification of the neurons, leading to lesions.
UWD is also associated with an inability to recognize fear in the facial expressions of others and to experience fear as evidenced in the novel case of patient who lost both amygdalae to the disease.
There is currently no cure for this condition, and treatment is based on signs and symptoms since they vary widely between individuals.
Klüver-Bucy (KB) Syndrome
KB is caused by trauma to the brain, viral brain infections like herpes simplex encephalitis, or other degenerative diseases like Alzheimer’s. People with this very rare neurological syndrome experience memory loss, oral fixation, extreme sexual behavior, and overall peculiar behavior.
Such drastic changes are the result of amygdala lesions damaging both temporal lobes of the brain. These lesions are said to be the cause behind a KB patient’s abnormal emotional responses, including unjustified aggressiveness, fearlessness, and apathy, all of which are associated with amygdala dysfunction.
The cerebellum is separated from the medulla and pons by the fourth ventricle and is inferior to the occipital lobes of the cerebrum. As you already know, many of the functions of the cerebellum are concerned with movement. These include coordination, regula-tion of muscle tone, the appropriate trajectory and endpoint of movements, and the maintenance of pos-ture and equilibrium. Notice that these are all invol-untary that is, the cerebellum functions below the level of conscious thought. This is important to permit the conscious brain to work without being overbur-dened. If you decide to pick up a pencil, for example,
the impulses for arm movement come from the cere-brum. The cerebellum then modifies these impulses so that your arm and finger movements are coordinated, and you don’t reach past the pencil.
The cerebellum seems also to be involved in certain sensory functions. For example, if you close your eyes and someone places a tennis ball in one hand and a baseball in the other, could you tell which was which? Certainly you could, by the “feel” of each: the texture and the weight or heft. If you pick up a plastic con-tainer of coffee (with a lid on it) could you tell if the cup is full, half-full, or empty? Again, you certainly could. Do you have to think about it? No. The cere-bellum is, in part, responsible for this ability.
To regulate equilibrium, the cerebellum (and mid-brain) uses information about gravity and movement provided by receptors in the inner ears.
Fact or Fiction?: A Cockroach Can Live without Its Head
A nuclear war may not trouble them, but does decapitation?
To understand why cockroaches&mdashand many other insects&mdashcan survive decapitation, it helps to understand why humans cannot, explains physiologist and biochemist Joseph Kunkel at the University of Massachusetts Amherst, who studies cockroach development. First off, decapitation in humans results in blood loss and a drop in blood pressure hampering transport of oxygen and nutrition to vital tissues. "You'd bleed to death," Kunkel notes.
In addition, humans breathe through their mouth or nose and the brain controls that critical function, so breathing would stop. Moreover, the human body cannot eat without the head, ensuring a swift death from starvation should it survive the other ill effects of head loss.
But cockroaches do not have blood pressure the way people do. "They don't have a huge network of blood vessels like that of humans, or tiny capillaries that you need a lot of pressure to flow blood through," Kunkel says. "They have an open circulatory system, which there's much less pressure in."
"After you cut their heads off, very often their necks would seal off just by clotting," he adds. "There's no uncontrolled bleeding."
The hardy vermin breathe through spiracles, or little holes in each body segment. Plus, the roach brain does not control this breathing and blood does not carry oxygen throughout the body. Rather, the spiracles pipe air directly to tissues through a set of tubes called tracheae.
Cockroaches are also poikilotherms, or cold-blooded, meaning they need much less food than humans do. "An insect can survive for weeks on a meal they had one day," Kunkel says. "As long as some predator doesn't eat them, they'll just stay quiet and sit around, unless they get infected by mold or bacteria or a virus. Then they're dead."
Entomologist Christopher Tipping at Delaware Valley College in Doylestown, Pa., has actually decapitated American cockroaches (Periplaneta americana) "very carefully under microscopes," he notes. "We sealed the wound with dental wax, to prevent them from drying out. A couple lasted for several weeks in a jar."
Insects have clumps of ganglia&mdashnerve tissue agglomerations&mdashdistributed within each body segment capable of performing the basic nervous functions responsible for reflexes, "so without the brain, the body can still function in terms of very simple reactions," Tipping says. "They could stand, react to touch and move."
And it is not just the body that can survive decapitation the lonely head can thrive, too, waving its antennae back and forth for several hours until it runs out of steam, Kunkel says. If given nutrients and refrigerated, a roach head can last even longer.
Still, in roaches, "the body provides a huge amount of sensory information to the head and the brain cannot function normally when denied these inputs," explains neuroscientist Nick Strausfeld of the University of Arizona, who specializes in arthropod learning, memory and brain evolution. For instance, although cockroaches have a fantastic memory, "when we've tried to teach them when they had bits of them missing, it's hopeless. We have to keep their bodies completely intact."
Cockroach decapitation may seem macabre, but scientists have conducted many experiments with headless roach bodies and bodiless roach heads. Decapitating roaches deprives their bodies of hormones from glands in their heads that control maturation, helping researchers investigate metamorphosis and reproduction. And studies of bodiless roach heads shed light on how their neurons work. Plus, it provides just one more testament to the cockroach's enviable endurance.
Worm Turns Grasshoppers Into Zombies
The hairworm (Spinochordodes tellinii) is a parasite that lives in fresh water. It infects various aquatic animals and insects including grasshoppers and crickets. When a grasshopper becomes infected, the hairworm grows and feeds on its internal body parts. As the worm starts to reach maturity, it produces two specific proteins that it injects into the host's brain. These proteins control the insect's nervous system and force the infected grasshopper to seek out water. Under the control of the hairworm, the zombified grasshopper plunges into the water. The hairworm leaves its host and the grasshopper drowns in the process. Once in the water, the hairworm searches for a mate to continue its reproductive cycle.
How to Dissect a Cockroach
Ever wondered what those little pests called cockroaches are really made of? Thought of trying to dissect one yourself but didn’t know how to do it? Well, the answer is here. In the following article I will discuss two methods of dissection for cockroaches and 2 methods for killing them, one more humane than the other.
If taking a more scientific and humane approach, one method is to knock out the cockroach using carbon dioxide (dry ice) or nitrogen. From here, you may continue with the dissection knowing that the subject will not feel any pain.
The first step to dissecting a cockroach is to gather a tray and fill it half way with a firm dissection gel. Then, place the cockroach backside down against the gel and using pins pin down all both of its wings, and then remove all 6 of its legs. Extra pins may be inserted through the wings to further stabilize the cockroach. Next, take the scalpel and make ventral cuts along the abdomen to remove the exoskeleton (using medical scissors). Once the exoskeleton has been removed, one must remove the fat body using forceps to expose the internal organs of the cockroach. Some of the major structures inside a cockroach are the crop, gastric caeca, midgut, Malpighian tubules and hindgut.
Another method of dissection is to first kill the cockroach in a jar which is far less humane than anesthetizing it first. Afterwards, you would precede to remove the head from the cockroach to separate it from its internal organs. From this point forward, one would follow the steps mentioned above to begin removing the exoskeleton.
Ever wondered what their internal organs actually do? Well, the crop, which is an enlargement of the foregut, serves as a temporary storage area for food. This is where digestion of the complex sugars begins, which is aided by the bacteria found in the gastric caeca (elongated pouch at the beginning of the midgut). The Malpighian tubules are actually the primary organs of the excretory system. Their function is to remove nitrogen-containing wastes and regulate water and salts in an insect’s blood, called hemolymph. Contents from the midgut and Malpighian tubules empty into the hindgut, where final resorption of water, salts, and nutrients from the feces and urine takes place before excretion.
Now when your faced with the question of “How does one dissect a cockroach” not only will you be able to respond with 100% accuracy, you also will be able to include a few fun facts about the function of the major structures found inside a cockroach.
Cockroach is dioecious or unisexual. They have well developed reproductive organs. The male reproductive system consists of a pair of testes, vasa deferentia, an ejaculatory duct, utricular gland, phallic gland and the external genitalia. A pair of three lobed testes lies on the lateral side of the 4th and 6th abdominal segments. From each testis arises a thin vas deferens, which opens into the ejaculatory duct through the seminal vesicles. The ejaculatory duct is an elongated duct which opens out by the male gonopore lying ventral to the anus.
A utricular or mushroom shaped gland is a large accessory reproductive gland, which opens into the anterior part of the ejaculatory duct. The seminal vesicles are present on the ventral surface of the ejaculatory duct. These sacs store the sperms in the form of bundles called spermatophores. The duct of phallic or conglobate gland also opens near the gonopore, whose function is uncertain. Surrounding the male genital opening are few chitinous and asymmetrical structures called phallomeres or gonapophyses which help in copulation.
The female reproductive system of cockroach consists of a pair of ovaries, vagina, genital pouch, collaterial glands, spermathecae and the external genitalia. A pair of ovaries lies laterally in the 2nd and 6th abdominal segment. Each ovary is formed of a group of eight ovarian tubules or ovarioles, containing a chain of developing ova. The lateral oviducts of each ovary unite into a broad median common oviduct known as vagina, which opens into the genital chamber. The vertical opening of the vagina is the female genital pore. A pair of spermathecae is present in the 6th segment, which opens by a median aperture in the dorsal wall of the genital pouch. During copulation, the ova descend to the genital chamber, where they are fertilized by the sperms. A pair of white and branched collaterial glands present behind the ovaries forms a hard egg case called Ootheca around the eggs. Genital pouch is formed by the 7th, 8th and 9th abdominal sterna. The genital pouch has two chambers, a genital chamber into which the vagina opens and an oothecal chamber where oothecae are formed. Three pairs of plate like chitinous structures called gonapophyses are present around the female genital aperture. These gonapophyses guide the ova into the ootheca as ovipositors. (Figure 4. 14).
Ootheca is a dark reddish to blackish brown capsule about 12mm long which contains nearly 16 fertilized eggs and dropped or glued to a suitable surface, usually in crack or crevice of high relative humidity near a food source. On an average, each female cockroach produces nearly 15 – 40 oothecae in its life span of about one to two years. The embryonic development occurs in the ootheca, which takes nearly 5 – 13 weeks. The development of cockroach is gradual through nymphal stages (paurometabolus). The nymph resembles the adult and undergoes moulting. The nymph grows by moulting or ecdysis about 13 times to reach the adult form.
Many species of cockroaches are wild. About 30 cockroach species out of 4,600 are associated with human habitats. About four species are well known as pests. They destroy food and contaminate with their offensive odour. The mere presence of
cockroaches is a sign of unhygienic condition and they are also known to be carriers of a number of bacterial diseases. The cockroach allergen can cause asthma to sensitive people.