Cognitive Neuroscience Lecture 19: Cognitive Control

*L19: Cognitive*
Control

Cognitive control, goal-oriented behavior, and prefrontal
cortex

**Cognitive control:** mental
abilities that involve planning, controlling, and regulating flow of info
processing

**Goal oriented**
behavior**: interacting with the world in a purposeful manner**

Prefrontal needed for both.

All areas in front of primary and secondary motor areas =
PFC

**John Fulton: lobotomy**
in chimpsàcalm

**Egas Moniz: lobotomy**
in humansà worked but not in all cases

**Walter Freeman: ice**
pic lobotomy

Made patients listless

Evidence from nonhuman primates

Monkeys with LPFC lesions failed at delayed
response task (**working memory)**

Location of food reward varies randomly from
trial to trial

Able to do associative memory trial, but unable
to do **working memory task** (no cue)

Cells in prefrontal responds when cue turned off
until response

PFC and recency/source memory: humans & aging

Recency depends on ability to segregate and
organize infoà
affected by PFC damage

Tested in patients with parts of pfc removed for
epilepsy

**Frontal lobe damage**
did worst on recency test

Recency defecits observed only in patients with lesions to
DLPFC—right DLPFC for object stim and left DLPFC for word stim

Central exec of Baddeley Hitch = DLPFC

Source memory:Where info was learned

DLPFC damage ruins source info

Glisky et al: neuropsych: high/low frontal lobe,
high/low medial temporal lobe

Low frontal lobe functionàpoor source memory

Low temporal lobe functionàpoor item memory

Testing Frontal activity during retrieval of source memory

Encode individual words: pleasant/unpleasant,
concrete or abstract

Test: one of pair

o
**Source**
test: pleasant/unpleasant? à Left lateral
prefrontal activation>

o
**Recency:**
which was most recent? à right lateral
prefrontal activation>

Componential approaches to PFC

**Content-based**
accounts**: focus on the relation of verbal vs. spatial information to**
particular prefrontal regions, typically in working memory paradigms

Instruction cue indicates task required for
trial

**Bilateral**
superior prefrontal & parietal, right inferior frontal: spatial

**Left**
inferior/lateral prefrontal, temporal: verbal

**Anterior**
PFC, near frontal pole, similar for both tasks

**DLPFC**
more active when stim remembered in backward order for any content

**Process-based**
accounts**: focus on processing differences in specific prefrontal regions,**
especially role of task complexity in driving prefrontal activity, such as
N-back task effects & task manipulations related to hierarchical
organization

**Hierarchical task**
manipulation:

Simple stimulus-response rules: press x when y

Add task contingencies: press x when specific
instance of y

**More**
complex contingencies: change rules between blocks

**Prefrontal**
activation got more and more anterior suggesting hierarchical organization

Cognitive control of goal directed behavior

Many processes: need PFC

Identify goals, filter goals, switch tasks

**Lateral**
prefrontal lesions have trouble with goal directed behavior

o
Do not go in a logical order when given a list

Tasks that pinpoint lateral prefrontal damage:
Wisconsin card sorting

o
Normal people will guess and check after rule
stops working

o
Lateral PFC damage are prone to perseverate

**Prefrontal**
cortex also contributes to selecting task-relevant information (filtering)

o
**Dynamic**
filtering: left inferior frontal cortex , left temporal

o
This is the part damaged in people who do bad
for high filter

**Task**
switching:

o
Task goal switched every 2 trials: color/color
or num/letter

o
Prefrontal cortex patients have greater RT
“switch cost” only for color cue

§
Color cue involves more complex mapping than
num/letteràmore
WM demands

Anterior Cingulate Cortex: monitoring conflict

o
Error related negativity

o
“incompatible”