Introductory Psychology and Brain & Cognition Summary Interim 4

Complete Summary Introductory
Psychology and Brain & Cognition
Chapter 5 Motor Systems: The Organization of Action ...................................................................... 2
Chapter 8 Memory: Varieties and Mechanisms ................................................................................ 13
Chapter 10 Emotion ......................................................................................................................... 27
Chapter 11 Social Cognition ............................................................................................................. 39
Chapter 12 Language........................................................................................................................ 49
Chapter 13 Executive Functions ....................................................................................................... 58
Chapter 14 Decision Making ............................................................................................................ 72




1

,Chapter 5 Motor Systems: The Organization of Action
Local circuits of motor organization can produce simple reflexes on their own, but broader and more
planned out behavior is governed by descending projections from the upper motor neurons in the
primary motor cortex and other premotor areas of the frontal and parietal lobes.

All higher motor areas are monitored by the cerebellum (correct errors in ongoing movements) and
the basal ganglia (facilitate learning of simple movements).
The basal ganglia and the cerebellum are also involved in motivation, emotion, and decision making.

Introductory box Apraxia
Apraxia: Greek for “without act or deed”. The loss of the ability to execute learning voluntary
movements, despite having the physical ability to be able to do the movement. There
are different types of apraxia:

• Ideomotor apraxia
o Inability to voluntarily perform a leaning action when presented with the
appropriate objects.
o Inability to imitate what someone else is doing
o Inability to follow verbal instructions.
• Ideational apraxia
o Inability to carry out a sequence of movements involving the use of tools
or objects in the proper order.
• Verbal apraxia
o Difficulty producing speech.

Motor Control is Hierarchical
Observations like the overall form of someone’s signature staying the same, regardless of it being
written with their hand, the pen attached to their wrist, shoulder, shoe or even in the mouth,
supports the idea that complex behaviors are organized at several levels.

The highest level are motor programs, which are sets of commands to initiate a sequence of
movements. Motor programs are independent of the actual muscle groups that carry out the
movements.

The lowest level of the motor control hierarchy are elementary behavioral units that directly activate
muscles.
A variety of intermediate processing levels intervene between motor programs and the elementary
units of motor control, which cause the movements to be precisely coordinated.

Anatomical Organization of Motor Systems
The neural circuit controlling skeletal movements can be divided into four distinct, but interacting
subsystems:

Upper motor neurons in the cortex and brainstem, lower motor neurons in the spinal cord and
brainstem, the cerebellum, and the basal ganglia.




2

,The lower motor neurons in the spinal cord and
brainstem

This subsystem is composed of lower motor
neurons(in the gray matter of the spinal cord and
brainstem), and local circuit neurons.

Lower motor neurons: send axons of the central
nervous system to directly
innervate skeletal muscle
fibers. These can be
considered synonymous with
the elementary behavioral
units.

Local circuit neurons: provide synaptic input to
lower motor neurons and contribute to the local coordination of lower motor
neuron activity, especially important for the coordination of reflexes engaged
in rhythmic activities, like chewing or walking.

The upper motor neurons in the cortex and brainstem

Upper motor neurons: provide descending control of local circuitry in the spinal cord and brainstem.

The cerebellum and Basal Ganglia

Modulate the activity of upper motor neurons in order to make corrections and to help initiate goal-
directed movements.

Cortical Pathways for Motor Control
Descending projections from the cerebral cortex to brainstem and spinal cord originate from upper
motor neurons within the primary motor cortex, and the adjacent premotor cortical areas, including
the premotor cortex and supplementary motor cortex.

The primary motor cortex is distinguished by the very low current needed to evoke movements.
Which indicated that upper motor neurons in this area have relatively direct access to local circuit
neurons and lower motor neurons in the brainstem and spinal cord.

The axons of the upper motor neurons in the primary motor cortex innervate neurons in the brain
stem (such as those controlling the muscles of facial expressions) branch off at appropriate levels.
The axons that continue to the spinal cord merge and descend through the medullary pyramids in
the pyramidal tract.

(See pictures on next page)




3

, figure 5.4 Upper
Motor Neuron
pathways

(A) The primary motor cortex and
premotor cortical areas. The primary
motor cortex is located in the
precentral gyrus. The motor and
supplemental premotor areas are
more rostral in the frontal lobe.
(B) Descending pathways from the primary
motor cortex. pathway to the spinal
cord and the lateral corticospinal tract
in cross section.




Figure 5.5 Organization of the lower motor
neurons in a cross section of the cervical spinal cord.

Motor neurons innervating proximal muscles (I.e., those
closest to the shoulder) are located medially (close to the
midline); those innervating distal muscles (towards the
digits) are located laterally (to the right or left)




4