Chapter 4: The Neural Basis of Behavior

Question 1

explain how centris pallida male nervous systems aren’t very discriminating?

Answer 1

The bee’s nervous system responds to simple operating rules. When a sexually active male grasps an object about the size of a female, the sensory signals generated by its touch receptors eventually translate into a complex series of muscle commands.

Question 2

Explain how niko tingerben exmained the link between simple stimuli and complex responses in gulls

Answer 2

Niko Tinbergen examined the link between simple stimuli and complex responses in gulls He found that baby gulls peck at small sticks with black and white bands in the same way they peck at their parent’s bill Adult gull responds to these pecks by regurgitating food.

Baby gulls ignore most of the cues provided by the adult and focus on bill colouring.

From this image, you can see that all that matters is the red coloring or black and white bands. it doesn’t even matter if the mom is a stick rather than a bird head.

Question 3

ethology

Answer 3

the first discipline dedicated to the study of both the proximate and ultimate causes of animal behavior.

Question 4

instinct

Answer 4

an innate behavioral pattern that appears fully functional from the first time it performed, even if the animal has had no previous experience with cues that elicit the behavior.

Question 5

the simple cue that triggers the instinct is called _____

Answer 5

sign stimulus/ releaser

Question 6

an instinct is aka

Answer 6

fixed action pattern

Question 7

the neural network responsible for DETECTING the simple cue AND ACTIVATING the instict:

Answer 7

innate releasing mechanism.

Question 8

Explain how a releaser triggers an insinct (using the red gulls as an example)

Answer 8

Certain sensory messages from the releaser (in this case the red dot on the bill of the adult gull) are processed by innate releasing mechanisms (neuronal clusters) higher in the nervous system, leading to motor commands that control a fixed action pattern, a preprogrammed series of movements that constitute an adaptive reaction to the releasing stimulus

Question 9

Explain the greylag goose experiment conducted by Niko Tinbergen and Konrad Lorenz

Answer 9

they identified a simple stimulus capable of triggering a complex behavior in the greylag goose.

greylag goose have a perceptual mechanism that is highly sensitive to visual cues provided by eggs.

the sensory mechanism must send info to neurons in the brain that automatically acivates an invariant motor program. An egg repeatedly falling out of the nest triggers the greylag goose to continually pull it back into the nest, even though konrad was pulling it by a string.

Question 10

3 steps to a fixed action pattern

Answer 10

1. The Sign Stimulus (or releaser) activates the:
2. Innate releasing mechanism that induces a:
3. Fixed action pattern

Question 11

beer bottle crisis of the male jewel beetle

Answer 11

Male jewel beetles trying to mate with objects other than female beetles.This large Australian beetle will attempt to mate with any object approximately the same colour as a female of his species.

Question 12

Bats _____using sound frequencies between 20 and 80 KHz, well above human hearing range, but not above that of moths

Answer 12

Bats echolocate using sound frequencies between 20 and 80 KHz, well above human hearing range, but not above that of moths hearing range.

Question 13

2 hypothesis about how moths avoid bats

Answer 13

1) echolocation hypothesis. ultrasonic calls or echolocation are used by bats to locate food and navigate at night
2) ultrasound evasion hypothesis:insects are able to hear pulses of bat ultrasound created by bats

Question 14

explain how moths can hear ultrasounds of bats and how their reflex is triggered? What is the reflex called?

Answer 14

ears synapse with thoracic ganglia which synapse to te brain in a moth.

in the ear, there are 2 auditory receptors (A1 and A2) that are linked to the tympanum that vibrates when exposed to sounds. These receptor cells are deformed when the tympanum vibrates.

these A1 and A2 cells are mechanosensitive and fire action potentials to INTERNEURONS that connect to the thoracic ganglia of the moth. action potentials produced in the thoracic ganglia reach motor neurons, which activate the wings and allows moths to mobilize within a fraction of a second after the tympanum was deformed. This reflex is called the ESCAPE DIVE.

Question 15

___ and A2 receptors are specialized for the detection of ____ stimuli in moths

Answer 15

A1 and A2 detect ultrasonic stimuli

Question 16

out of the two ultasonic receptors in a moth, which one is more sensitive?

Answer 16

Sounds of low or moderate intensity do not generate action potentials in the A2 receptor. The A1 receptor fires sooner and more often as sound intensity increases.

The A1 receptor initially reacts strongly to pulses of ultrasound but then reduces its rate of firing if the stimulus is a constant sound.

Question 17

how might moths locate bats in space ultrasonically if the bat is to the side of the moth? if the bat is on top of the moth? behind the moth?

Answer 17

When the bat is to one side of the moth, the A1 receptor on the side closer to the bat fires sooner and more often than the shielded A1 receptor on the other side.

When a bat is above the moth, activity in the A1 receptor fluctuates in synchrony with the moth’s wingbeats: wings up = more firing in response to sound, wings down = less firing in response to sound. this is because when the wings are down the moth is “covering its ears”

When a bat is directly behind the moth, both A1 receptors fire at the same rate and same time, both receptors are equally stimulated.

Question 18

Command center hypothesis

Answer 18

Nervous systems are organized to avoid maladaptive conflicts between competing stimuli via command centers in the brain

Example: The protocerebral ganglion (brain) of of the mantis

Question 20

explain the escape behavior by a sea slug

Answer 20

The slug’s dorsal muscles are maximally contracted, drawing the slug’s head and tail together; ventral muscles will soon contract and slug will thrash away.

The sea slug Tritonia diomedea engages in escape behaviour when it encounters a sea star – it thrashes back and forth and with luck avoids being a sea star lunch.

How does it manage this multistep swimming process?

This requires 2 to 20 alternating bends involving contraction of sheet of muscles on back followed by contraction of muscles on belly

Dorsal and ventral muscles are underthe control of a small number of motor neurons.

Question 21

in terms of the neural control of the sea slug escape response, the ___ ____neurons (DFN) are active when the animal is being bent into a U; the ____ _____neuron (VFN) produces a pulse of action potentials that turn the slug into an inverted U. What controls the alternating pattern of DFN and VFN activity?

Answer 21

The dorsal flexion neurons (DFN) are active when the animal is being bent into a U; the ventral flexion neuron (VFN) produces a pulse of action potentials that turn the slug into an inverted U.

A simple neural network headed by the dorsal ramp interneurons that interacts with the VFN and DFN imposes order on the activity of the motor neurons that control the dorsal and ventral flexion muscles means this mechanism qualifies as a central pattern generator

Question 22

Two types of midshipman males.

Answer 22

TYPE I: large territorial males that sing to attract females

TYPE II: smaller ‘satellite’ males that do not defend territories: they are female mimics that attempt to sneak on to TYPE I male territories

Question 23

How do male midshipman produce their songs?

Answer 23

The air bladder is sandwiched between layers of muscles.

Sonic muscles control the movement of the swim bladder controlling the fish’s ability to sing.

The bladder serves as a drum; rhythmic contractions of the muscles beat the drum.

Question 24

Explain the cortical mapping of the plainfin midshipman. Which nuclei are involved?

Answer 24

Muscle contractions require signals from motor neurons which are connected to sonic muscles.

Studied by Andrew Bass and colleagues who mapped the sonic control system

They found two clusters of interrelated neurons that generate the signals controlling the coordinated muscle contractions required for humming.

Signals FROM the forebrain and midbrain travel to three distinct neuronal populations in the hindbrain: vocal prepacemaker nucleus (VPP); vocal pacemaker nucleus (VPN); and vocal motor nucleus (VMN). Axons from the VMN coalesce into a vocal nerve that exists the brain and connects to vocal muscles in the swim bladder.

Question 25

Explain the difference in vocal circuits nad physiology behind the type 1 and type 2 midshipman males. Benefits and trade offs between the two types?

Answer 25

There are differences in the size and development patterns of the TYPE I and II males. Type I males have larger motor neurons and a larger volume vocal motor nucleus (VMN) than TYPE II males.

Type II males reach sexual maturity before TYPE I males, suggesting there is a life history tradeoff between investment in the strategy of TYPE I males (larger body size and vocal motor system) and TYPE II males (earlier reproduction and gonald development).

Question 26

explain the stimulus filtering in the brain of star nose moles

Answer 26

star moles live in the soil and don’t need their eyes very much. thus their eyes are an energetically expensive useless structure to maintain. therefore, their eyes greatly reduce in size, but their tactile inputs take up majority of the brain homonculus structure instead

Star-nosed mole lives in wet, marshy soil where it hunts for earthworms.

It can’t see in its burrows and its eyes are greatly reduced in size.

It ignores visual information and instead relies on tactile information.

Question 27

the tactile apparatus of a starnosed mole: The 22 appendages of the star-nosed mole’s nose are covered with thousands of ____ _____. Each organ contains a variety of specialized ____ ____ that respond to ____ deformation of the skin above them.

Answer 27

The 22 appendages of the star-nosed mole’s nose are covered with thousands of Eimer’s organs. Each organ contains a variety of specialized sensory cells that respond to mechanical deformation of the skin above them.

Question 28

which appendage of the star nosed mole the most important?

Answer 28

appendage 11, the thickest appendage near the nostrils. about 25% of the sensory cortex is devoted to appedage 11

Question 29

the more sensitive and important a structure is, the ____ the average area of cortex per unit fiber.

Answer 29

HIGHER. 11th appendage in mole rats are the most sensitive, and it takes up most space of the somatosensory cortex. it takes up more space at the expense of other sensory strcutures.

Question 30

cognition

Answer 30

The mental process of acquiring knowledge and understanding through thought, experience, and the senses.

Question 31

social brain hypothesis as to why we have such big energetically- costly brains

Answer 31

Advanced problem solving evolved in the the context of solving obstacles to reproductive success posed by members of own species

An increase in intelligence in some individuals could favour an increase in the social intelligence of others, setting up a positive feedback loop

The hypothesis was later revised to emphasize the role of pair bonding in social species that favoured a larger brain

Question 32

evidence for social brain hypothesis

Answer 32

Evidence for the social brain hypothesis is mixed. Group-living spotted hyenas do have larger brains than solitary hyena species.

But work in carnivores and primates has failed to support the social brain hypothesis.

Question 33

explain the domestication hypothesis of brain growth

Answer 33

Domesticated animals evolved an inherent sensitivity to human gestures but non-domesticated animals did not. Dogs do better than wolves reared in the same way when it comes to using human-provided cures such as gazing at a food-bowl or pointing to it.

Question 34

metabolic rate hypothesis for brain growth

Answer 34

humans have experienced an acceleration in metabolic rate, providing energy for larger brains and faster reproduction without sacrificing maintenance and longetivity.

Question 35

expensive tissue hypothesis for brain growth

Answer 35

the high metabolic requriements of human brains are offset by a corresponding reduction of their digestive tract, which are metabolically expensive to maintain.