PSYC 2: Biological Foundations - Fall 2012 - Professor Claffey

Notes: Cognition 1

Version:
11/14/12 - original version

Research Methods

Cognition - some of the most interesting topics, but some of the most difficult to define

_________________ a concept
    To decide on a strict definition for study, which may or may not satisfy other people's concepts

Research may or may not investigate the _________________ basis of behavior
    Fields that typically include neuro: neuroscience, neuropsychology, cognitive neuroscience, neurology
    Fields that less typically include neuro: psychology, cognitive science, psychophysics

_________________ / _________________ - describe but can not explain
    Neuroimaging - measuring activity in areas of the brain (e.g. fMRI, EEG, PET)
    Electrophysiology - measuring activity from one or more neurons
    Lesions - comparing differences in behavior caused by existing lesions
    Can be applied for both humans & animals subjects

_________________ / _________________ - can attribute results to a cause
    Stimulation - increasing/decreasing activity in the brain
    Lesions - destroying specific areas of the brain and comparing to controls
    Drug studies - administering chemicals to affect activity and comparing to controls
    Genetic knock-outs/ins - modifying the genetic make-up of an organism
    Typically limited to animal subjects

Executive Function

"forming and maintaining a task plan" (Duncan et al)
"regulate, control, and manage other cognitive processes" (Elliott 2003)

Concepts

Prefrontal Cortex (PFC) Anatomy

PFC reaches largest relative size in _________________
    Comprises ____ of the surface area of the human cortex

Key areas for this lecture
    Dorsolateral prefrontal cortex (DLPFC)
    Dorsomedial prefrontal cotex and anterior cingulate cortex (ACC)
    Ventrolateral prefrontal cortex, specifically the right inferior frontal gyrus (rIFG)

prefrontal cortex anatomy prefrontal cortex across species

Lesions to PFC

Phineas Gage
Railroad worker in 1848
metal rod passed through PFC
became impulsive, rude, unreliable
Phineas Gage
Source: boeatau.wordpress.com
Patient A
39 year old stock broker: restrained, modest

had large bilateral frontal lobe resection to remove a tumor

became boastful, lacked restraint, inappropriate in conversation, unable to plan for future, supported by family

could: learn complex procedures, play expert checkers, communicate, recognize his own deficits

(Source: Brickner, as cited in Neuroscience (1999), ed. by Purves, P474)

Experimental Evidence

Do you agree that the described concept (e.g. working memory, conflict) that is being tested by the task?

Experiment: Delayed Response

Concept: ______________________________
delayed non-match to sample task Task
Cue - Subject is shown a choice to remember (for monkeys, the location of food)
Delay - Subject is shown nothing, has to remember location/choice
Response - Subject allowed to make choice

Results
Monkeys - electrodes in area *like* DLPFC are active throughout delay and at response
Humans - fMRI shows increased blood flow in DLPFC throughout delay and at response

Summary
Prefrontal areas are active during working memory maintenance

Experiment: Delayed Non-match to Sample

Concept: ______________________________


delayed non-match to sample task
Task: Recognition (above right in diagram)
First, select any of 3 objects, move it aside, retrieve food from underneath
Second, choose between 2 objects, select the one that you DID pick last time
Requires: picking the object that you recognize, that feels familiar
Task: Monitoring (above left in diagram)
(same) First, select any of 3 objects, move it aside, retrieve food from underneath
Second, choose between 2 objects, select the one that you DIDN't pick last time
Requires: both objects are familiar, so remember which you picked and ______________________________
Results
DLPFC lesions affect/don't affect recognition, affect/don't affect monitoring
Summary
DLPFC is not necessarily saving information, but managing what is _________________/important (monitoring)

Experiment: N-back task

Concept: __working memory__
Online task

n back task
n back task results

Task:
Letters are presented in sequence (can be auditory or visual)
In the 0-back condition, subject has to react when the letter matches a target (here, when the letter is "X")
In the 1-back condition, subject has to react when any letter matches the previous letter (1 back)
In the 2-back condition, subject has to react when any letter matches the letter 2 back
Requires rotating letters in memory and constant monitoring
Results
With increasing n (the number of letters to be remembered), there was increasing blood flow in the DLPFC
Summary
A complex working memory task not only activated the DLPFC,
but a more _________________ task produced _________________ activations

Experiment: Stroop Task

Concept: _________________
stroop task
Source: http://scienceblogs.com/cognitivedaily/2007/07/05/the-stroop-effect-not-as-autom-2/

Task: _________________ version (easy)
Read aloud the words on the left
Task: _________________ version (hard)
Read aloud the words on the right (the words, not the ink color)
Results
People are slower to read the incongruent version
Incongruent version has greater activation in the _______________________
Summary
ACC may be involved in detecting conflicts


error related negativity
Electroencephalography (EEG)
Monitor electrical signals on scalp
EEG provides precise changes across time
EEG does NOT provide precise location
Event related potential
When many similar events are averaged together, there are sometimes reliable positive/negative changes in signal

______________________________
Have subjects repeat many trials, they sometimes make errors
Average all the error trials together
Within fractions of a second of making an error, there is a signal
Signal is strongest over _________________ cortex

Summary
Dorsomedial PFC not only detects external _______________,
but internal conflicts like _________________

   
Theory
This is a hypothesis but isn't confirmed by data
ACC detects conflict, DLPFC boasts activity in brain areas responsible for the task to resolve conflict
this is called _________________ control

Experiment: Stop Signal Task

Concept: ______________________________

stop signal cues
right inferior frontal gyrus
Task
On most trials, press space bar as quickly as possible after GO signal
On a few random trials, a STOP signal appears a split-second after GO signal
   Subject has to try to stop the button press action they have just started
Results
Patients with damage to right inferior frontal gyrus (rIFG) have deficits
Patients with damage to left inferior frontal gyrus do not have deficits
Summary
rIFG may issue the command to inhibit actions / thoughts

Review

    Dorsolateral prefrontal cortex (DLPFC)

    Dorsomedial prefrontal cotex and anterior cingulate cortex (ACC)

    Ventrolateral prefrontal cortex, specifically the right inferior frontal gyrus (rIFG)


Copyright 2012 - Michael Claffey