PSY324: Cognition & Memory Week 1 Notes
Chapter 2 Notes:
Eyes and ears are important to cognitive psychology.
Brain is only 2% of body weight but
... [Show More] claims 20% of blood supply.
Specific cognitive mechanisms are associated with specific brain areas.
cognitive neuroscience is the area of research concerned with this relationship
(pg. 25)
The Brain as the organ of the mind
Brain is composed of specific parts or modules
modules: different parts of the brain, each of which is responsible for
particular cognitive operations
Gall and Spurzheim: Phrenology: the study of the shape, size and protrusions of
the cranium in an attempt to discover the relationships between parts of the brain
and various mental activities and abilities.
Phrenological charts purport to show where various psychological functions are
located in the brain.
3 Basic principles
The brain is the sole organ of the mind
Basic character and intellectual traits are innately determined.
Since there are differences in character and intellectual traits among
individuals as well as differences in various intellectual capacities within a
single individual, there must exist differentially developed areas on the
brain, responsible for those differences. Where there is variation in
function, there must be variation in the controlling structures.
believed that the more highly developed a function was, the larger it would be.
The larger the function, it would manifest as a protrusion on the skull.
Localization of function: Shepherd Ivory Franz: the idea that there is a direct
correspondence between specific cognitive functions and specific parts of the
brain.
Franz was an expert in ablation, a technique that destroyed parts of the cortex
and consequences for behavior are observed.
neither learning nor memory was dependent upon the properties of individual
cells, rather both were functions of the total mass of tissue (pg 28)
these results came to be formulated as two laws:
law of mass: learning and memory depend on the total mass of brain
tissue remaining rather than the properties of individual cells.
law of equipotentiality: even though some areas of the cortex may
become specialized for certain tasks, any part of an area can (within
limits) do the job of any other part of that area
The relation between mind and brain
consciousness: narrower concept; often taken to mean what we are aware of at any
point in time (pg 28)
mind: is a broader concept, it includes consciousness, but also encompasses
processes that may take place outside of our awareness
4 classic efforts toward understanding mind and brain
Interactionism: associated with Descartes
mind and brain are separate substances that interact with and
influence each other
Epiphenomenalism: “mind” is superfluous by-product of bodily functioning
a by product of brain functions and has no causal role in
determining behavior
belief that consciousness is irrelevant to an understanding of
behavior
steam from a steam whistle to a coal-powered locomotive
Parallelism: “mind” and brain are two aspects of the same reality and flow
in parallel
every event in the mind is accompanied by a corresponding event in
the brain
Isomorphism: mental events share the same structure
traced to Gestalt psychologists
Gestalt means form or configuration
argued that consciousness tends to be organized into a coherent
whole
an experience and its corresponding brain process share the same
pattern
difference between isomorphism and parallelism is that the latter
envisions more than a simple point for point correspondence
between mental events and brain events
external stimulus is constant but the internal subjective experience
varies.
Methods in Cognitive Neuroscience
Animal Models
an indirect route to investigating brain mechanisms in humans is provided by
animal models
almost everything we currently know about the micro-organization of brain
structure and function is derived from the study of animal brains (pg 30)
differences across species in terms of structure and function place strong
limitations on our ability to generalize from one species to another and from
animal models to humans
Behavioral Studies
combines our knowledge of normal sensory systems with precise stimulus
presentation and response recording
The study of brain injuries
brain injuries can serve as a kind of substitute for experiments that
provide evidence for the localization of one or more functions.
Broca’s aphasia: a deficit in the ability to produce speech as a result
of damage to Broca’s area
Broca’s area: the area of the brain’s left hemisphere that is
responsible for how words are spoken
Wernicke’s area: area of the brain’s left hemisphere that is
responsible for processing the meaning of words
Wernicke’s aphasia: A deficit in the ability to comprehend speech as
a result of damage to Wernicke’s area
Surgical Intervention
Roger Sperry, research on inter hemispheric transfer
inter hemispheric transfer: communication between the brain’s
hemispheres, enabled in large part by the corps callosum
conducted on cats and involved severing the optic chasm (area in the
brain where the optic nerves that transmit information from the eyes to the
visual cortex cross)
when the corpus callosum is severed, information transfer between
hemispheres is disrupted
each hemisphere appeared to be a separate mental domain operating
with complete disregard, indeed with a complete lack of awareness of
what went on in the other.
split brain: a condition created by severing the corpus callosum
the animal behaved as if it had entirely separate brains.
Perry argued that consciousness was an emergent property of the brain
emergent property: in Sperry’s sense, a property
that “emerges” as a result of brain processes, but is not itself a
component of the brain. In the case of the mind, this means
that consciousness is neither reducible to, nor a property of, a
particular brain structure or region.
emergent causation: in Sperry’s sense, causation brought
about by an emergent property. Once the “mind” emerges from
the brain, it has the power to influence lower level processes.
supervenient: In Sperry’s sense, describes mental states that
may simultaneously influence neuronal events and be
influenced by them.
Event-Related Potentials
CT / MRI on pg 34
event related potential (ERP): an electrical signal emitted by the brain after
the onset of a stimulus
Positron Emission Tomography
PET: an imaging technique in which a participant is injected with a
radioactive substance that mingles with the blood and circulates to the
brain. A scanner is then used to detect the flow of blood to the particular
areas of the brain
info on pg 36 [Show Less]