Chapter 3 - The Turn to the Brain

Question 1

How did cognitive scientists in the early years of the field address their inability to research the brain on a fine level? In what way did they regard it?

Answer 1

They treated the brain as a functional system, attempting to understand its functions and result of its inner complexities (the software to its biological and physical hardware). The brain and its functional systems were reverse engineered, in the sense that its functions and qualities were taken and attempted, and cognitive scientists attempted to find where they manifest in a system.

Question 2

How did Gorman and Sejnowski teach a system to detect the difference in rock and mine SONAR signals?

Answer 2

They used spectral analyzers to transform the echoes of SONAR signals into frequency values, and ran those values through the system, with an input frequency being matched with an expected output of either mine or rock. They continued this and used backpropagation to teach the system to recognize the difference in frequencies. Input units in the system respond to different frequencies, and through calibration of the weight of the system created connections that can reliably distinguish the SONAR signals of mines and rocks.

Question 3

How did Peterson et al. design their experiment to address the shortcomings of a PET scan and show the different areas involved in lexical processing?

Answer 3

They took PET scans of the brain during different similarly focused activities, and used the difference in the scans to determine what parts of the brain are specifically utilized for the task. Taking a base case of attention towards the center of a blank TV, they took scans during increasingly complex but relevant cases to document the functional regions used in each.

Question 4

How do parallel neural networks start, and how do they develop into their expected form/connection distribution?

Answer 4

Parallel neural networks start with a random weight assignment, and quickly recalibrate their weight as a result of inputs being sent in and a target output being meant to be reached. Natural algorithms changes the weight of the network until it reaches its final connection distribution.

Question 5

How do units compare with each other?

Answer 5

They are identical structurally. The difference between them is created through their interaction with units from other layers. Think of the weight of the system and the subsequent organization of connections between units.

Question 6

How was Ungerleider’s and Mishkin’s study of visual processes revolutionary in cognitive science?

Answer 6

It used bottoms up research methods, with the data gained from exploring the visual organs of the brain and experimenting on them being used to form theories on the overall function of the system as a whole.

Question 7

What approach to research was commonly used in cognitive science before the 1980s? What caused a shift away from it?

Answer 7

The top down approach to research and the formulation of theories, which was used because there weren’t many tools available for the research of the brain on a microscopic level and over time. Imaging and obversational tools emerged in the 1980s that allowed for the research of the brain in a way that facilitated the fields move towards bottoms up research

Question 8

What are limitations of the PET scan?

Answer 8

The PET scan can highlight areas with brain activity that does not involve the processes being examined, background activity.

Question 9

The PET scan can highlight areas with brain activity that does not involve the processes being examined, background activity.

Answer 9

It does not address the limits the brain and its structures, or the hardware, might place on the functioning of cognition and its qualities, the software as observed by cognitive scientists. Forgets the biological changes over time, with gradual but gracefull degradation in age. The temporal reality of cognition, with many of the simplified observed phenomena not reflecting real conditions, as a lot of the details are abstracted away. Reaction time in most contexts is inaccurate.

Question 10

What did Korbinian Brodmann do to serve king, country, and cognitive science?

Answer 10

He divided the cerebral cortex into 52 separate and functional areas.

Question 11

What did Peterson et al. prove in their experiment on lexical processing?

Answer 11

Word recognition and processing is parallel process. It suggested that visual information has a direct and separate paths into areas involved in articulately coding and motor programming

Question 12

What does removing the primary visual cortex from one hemisphere and the inferior temporal area from the other cause? Who experimented on and discovered this?

Answer 12

his does not affect visual capacity too much, as the information from the remaining primary visual cortex is sent to the other hemisphere via the corpus collosum to the remaining inferior temporal area. The biological observation was discovered via experiment by Ungerleider and Mishkin

Question 13

What does removing the primary visual cortex from one hemisphere and the posterior parietal cortex from the other cause? Who experimented on and discovered this?

Answer 13

This cripples visual capacity. Removing the primary visual cortex has negative effects on the functioning of the visual system, and removing the posterior parietal cortex from the other hemisphere results in severe deficiencies. The biological observation was discovered via experiment by Ungerleider and Mishkin

Question 14

What is a layer in parallel processing?

Answer 14

A layer is a layer of unconnected units that connects via its units to other layers. Its component units receive information from the previous layer, and sends them forward to the next one. Weighing is important in terms of what the units the units of a layer are connected to.

Question 15

What is a learning algorithm that continously loops until the input results in a target output and error has been diminished to near zero?

Answer 15

Backpropagation

Question 16

What is a parallel processing system? Who discovered and pioneered it?

Answer 16

Parallel processing is the splitting of a neural network into units organized into connected layers. Each unit can have activation values ranging between [-1, 1], which is determined by a units connection to other units in the previous layer. Rummelhart, McCelland, and the PDP research group. (Imagine Rommel with a beating heart in McDonalds sealand reading a pdf)

Question 17

What is a PET scan and how does it work?

Answer 17

A PET scan (positron emission tomography) is a functional scan of the brain, which records areas of activity in it.

It works by injecting (a safe amount of) radioactive oxygen-15 isotopes in water into the brain, and tracking their distribution by the emission of radiation.

Question 18

What is backpropagation?

Answer 18

A learning algorithm that continously loops until the input results in a target output and error has been diminished to near zero.

Question 19

What is learning in parallel processing systems?

Answer 19

Learning is essentially the modification of weight in a neural system such that when an input is placed into it, the real output will more closely approach the expected one.

This is an algorithmic shift??

Question 20

What is the idea of multiple realizability?

Answer 20

It is when the same function can be performed by more than one distinct structures. An example is the heart, which differs between animals.

Question 21

What is the idea of weight in parallel processesing? What properties does it allow for, and how does it change?

Answer 21

Weight is simply the connectivity of units across plates in a parallel neurological system.

It determines the path signals have to take, and because it can be changed, it allows for parallel systems to adapt.

When inputs are put through a system, it compares the real output with the expected output, and it modifies itself algorithmically to be able to more accurately output the expected values/functions. This process is called learning.

Question 22

What is the structure of a parallel neural network?

Answer 22

A parallel neural network is composed of multiple layers of units, with the first layer called the input layer receiving information from outside the system and the final layer called the output layer, much the same sending out.

The layers in between are called the hidden layers, which propagate and process information in a manner pertaining to the weight of the system. This occurs within the system itself

Question 23

What justifies the idea of multiple realizability?

Answer 23

Humans and animals have different brains and internal structures, but share similar cognition, with us both being able to feel pain, the cold, see, etc.

Question 24

What makes reverse engineering and to a certain extent studying the more complex parts of cognition less valuable?

Answer 24

The biological reality of multiply realizablity, which means that many of the functions in cognition can be performed by various structures of one is damaged.

Different structures can perform the same task, if one is damaged the other can replace it.

Question 25

What part of the brain is involved in the recognition of images?

Answer 25

The inferior temporal cortex, which is area 20 in Brocca’s division of the cerebral cortex.

Question 26

What part of the brain is involved in the recognition of objects in relation to space and the formation of virtual images? Which area is it?

Answer 26

The posterior parietal cortex, which is part of areas 7, 39, and 40 in Broddman’s division.

Question 27

What types of signals and informaation does the learning and using of a word involve?

Answer 27

• Visual signals, from the shape of the word in language
• Auditory signals, from the sound of its phenotic pronunciation
• Semantic information, which connects the word to an image or idea, gives it meaning.

Question 28

What was concluded from Ungerleider’s and Mishkin’s experiments?

Answer 28

It was revealed that visual information travels down two paths, and sensory information can be shared between the inferior temporal areas across the corpus collosum the primary visual cortex on one side is damaged (and if the inferior temporal area on the other hemisphere is removed), but:

The dorsal sense sustains damage after the removal of a single primary visual cortex, and is almost completely decimated if the opposing posterior parietal cortex is removed. That’s because the posterior parietal cortex is contralateral, and does not accept information from the wrong visual side well.

Question 29

What was the cognitive model for lexical access?

Answer 29

It held that the processing of lexical information involved different pathways simultaneously.

No singular route of travel for the information.

Question 30

What was the neurological model for lexical access?

Answer 30

Postulated that visual information involving words travels through the brain through a single, serial path.

It held that a word must be phenologically (meaning by sound) encoded before further meaning can be assigned to it.

Question 31

What were the limitations of the study Parallel Distributed Processing: Explorations in the Microstructure of Cognition, and what are its strengths? Who was involved in its research? Quickly, what was their theory?

Answer 31

It captures very general ideas of how the mind functions on a microscopic/biological level, but in its generality it abstracts biological details away.

The study is very useful in that it helps bridge the gap between algorithm and implentation by offering a theory as to how algorithms are formed and implemented.

Rummelhart, McClelland, and the PDP Research group (Imagine Rommel with a beating heart in McDonalds sealand reading a pdf).

They came up with the idea of parrallel processing and the units/organization involved in it.

Question 32

What were the two models for single word processing (lexical access)?

Answer 32

The neurological (series) model and the cognitive (parallel) model.

Question 33

What were the two primary routes in which visual information travel that Ungerleider and Mishkin identified?

Answer 33

he dorsal route, which takes information related to the objects in space.

The ventral route, which takes information involving the mental image, or the information involved in the recognition and identification of objects.

Question 34

What were Ungerleider’s and Mishkin’s experiments on? How were they conducted?

Answer 34

Ungerleider and Mishkin conducted experiments on the brains of monkeys, with them conducting fine surgey’s on their cerebrums.

They wanted to test the path visual information took in the brain, which was previously theorized to travel down a single information stream.

The experimentation was conducted by cutting away parts of the monkey’s brain in sequence, with:

first the primary visual cortex on one hemisphere being removed, and

subsequently either the inferior temporal area or the posterior parietal cortex respectively, and

finally the corpus collosum being cut.

It revealed that visual information travels down two paths, and sensory information can be shared between the inferior temporal areas across the corpus collosum the primary visual cortex on one side is damaged (and if the inferior temporal area on the other hemisphere is removed), but:

The dorsal sense sustains damage after the removal of a single primary visual cortex, and is almost completely decimated if the opposing posterior parietal cortex is removed. That’s because the posterior parietal cortex is contralateral, and does not accept information from the wrong visual side well.

Remember, untermensch brains, Ungerleider cut them

Question 35

Which of Brodmann’s areas is the visual cortex?

Answer 35

Area 17

Question 36

Who research parallel networks on the differentiation between mines and rocks in SONAR?

Answer 36

Gorman and Sejnowski}}

Question 37

Who split the cerebral cortex into 52 functional areas?

Answer 37

Korbinian Brodmann

Question 38

Who used PET scans to examine the mind during lexical processing?

Answer 38

Peterson et al.

Question 39

Why is a parallel processor (system) called what it is?

Answer 39

ts layers are composed on unconnected units, but the units of a layer are connected to and receive signals from multiple other units in the previous layer and send signals out to multiple units in the following one.

Like a parallel circuit in a way.

Question 40

Why is there a fear of false generalization in cognitive science?

Answer 40

The brain is highly flexible, or plastic, in the sense that if one of its parts is damaged, the brain can continue to function and more importantly compensate by forming new or activating already existing paths for the information to flow.

Structures adapt functions to a certain extent to address failures in others, like when proprioception failed that young wee lass and she had to use her vision instead.