Textbook Notes (368,558)
Canada (161,962)
Physiology (114)
PSL440Y1 (19)
A (18)
Chapter 7

Chapter 7

12 Pages
63 Views
Unlock Document

Department
Physiology
Course
PSL440Y1
Professor
A
Semester
Winter

Description
Chapter 7 Executive Processes Executive attention is the kind of selective attention that typically acts on the contents of working memory and directs further processing so as to achieve some goal. Executive processes organize our mental lives just as a corporate executive co- ordinates a businesss activities. Thus, the function is administrative. Executive processes are processes that modulate the operation of other processes and are responsible for the co-ordination of mental activity so that a particular goal is achieved. Executive processes are known as meta-processes i.e. all executive processes are meta- processes but not every meta-process is an executive one because it may or may not co- ordinate and control mental activity The Frontal Lobe Connection Frontal brain damage often occurs because of a closed head injury which is an injury caused by an external bump that does not pierce the skull. This frontal lobe area is most likely to get damaged since brains most sharpest and protruding ridge is adjacent to the frontal lobes so a blow on the skull cuts deepest in the frontal lobes The first evidence that executive processes are controlled by frontal lobes comes from the study of Phineas Gage who suffered damage to the frontal lobe and as a result of that lost the ability of social restraint. Frontal lobe patients perform relatively normal on an IQ test but are incapable of leading a normal life. They have all their cognitive components intact but they lose the ability to organize, co-ordinate and control these components. Patients with damage to the frontal lobe are rigid, inflexible, lack the ability to initiate action or the ability to plan. They are monotone, express little emotion and require continuous instructions. The deficit suggests that they lack the ability to self-monitor and have trouble in switching attention Frontal-lobe syndrome refers to the inability to sequence activities to achieve a goal The area primarily involved is the prefrontal cortex which is present directly in front of the pre-motor cortex and at its most posterior end has the Brocas speech area Prefrontal cortex is responsible for some of the more complex activities that human carry out such as mentally sequencing a list of activities Prefrontal cortex also acts like a co-ordinating center where is receives input from all perceptual and motor areas and sends signal back to exert a top-down influence Frontal executive hypothesis is the idea that every executive process is primarily mediated by the prefrontal cortex Frontal Damage and the Frontal Hypothesis A test that is designed for the patients with frontal lobe damage is called Stroop task where the participant is asked to name the color of ink and ignore the content of the word. The word and the color of the ink may be compatible or incompatible. Normal participants accuracy level was high even when the word and the ink was incompatible although took longer to respond in the incompatible condition. Frontal lobe patients with damage to the dorsolateral prefrontal cortex had a significantly lower level of accuracy. Stroop task requires two executive processes; selective attention and inhibition which are controlled by the prefrontal cortex The question raised is whether a common mechanism underlines both attention and inhibition Wisconsin card sort task is a test of frontal-lobe damage where 4 stimulus cards are presented in front of the participant and each has a distinct style. The participant is then given a deck of cards and is asked to match each card with those 4 model cards, but they are not told the criteria of matching. Participants start by guessing the critical attribute and by feedback eventually find out the right one. Then, the critical attribute is changed and the participants switch to the new attribute. No difference was observed between the normal participants and the participants with frontal-lobe damage but a big difference was observed in their ability to switch attributes. Normal participants successfully switch to the new attribute upon receiving feedback but the patients with frontal lobe damage keep on making mistakes and fail to switch attributes. Therefore, process of switching attention is compromised by frontal lobe damage Tower of Hanoi problem where only one disk can be moved at a time, a bigger disk cannot be placed on top of a smaller one. This task involves arranging the configuration of disks in the working memory, selectively attending some disks while selectively inhibiting others moreover, continuously updating the new configuration of the disks in the working memory each time after moving a disk, and then switching attention to the new disks that are to be moved. This task also involves decomposition of a bigger goal into smaller subgoals and therefore requires sequencing of steps Patients with damage to the dorsolateral prefrontal cortex perform poorly on the Tower of Hanoi problem; they tend to make many moves than normal participants to come up with a solution Alzheimers patients perform poorly on the frontal-lobe tasks because their prefrontal cortex area gets affect. Executive dysfunction refers to marked disorganization and failure in career Five major Executive Processes1. Executive Attention Executive attention directs subsequent processing and is required when multiple mental representations operate in the working memory or multiple processes operating on the mental representations compete for the control of cognition and behaviour Executive attention determines which mental representation or process will gain control e.g. in stroop task, the ink of the writing is allowed to gain control rather than the content of the word Another task called stimulus-response compatibility task is a measure of the degree to which the assignment of the correct response to a stimulus matches with the way people act naturally i.e. to what degree is the correct response provided automatic. Compatibility effect is obvious where people are presented with a stimulus and are required to press a key to indicate its presence with the hand that is on the same side as the stimulus in the compatible trial. And in the incompatible trial the hand on the opposite side is required to press a key to indicate the stimuluss presence. Participants are relatively quicker when the stimulus is presented on the same side as that of the hand making the response than when it is presented on the opposite side.
More Less

Related notes for PSL440Y1

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit