Cognition.Chapter 2.Lecture 3. Cognitive Neuroscience.
The goal of cognitive neuroscience is to discover the brain mechanisms that give rise to human
mental functions such as language,attention and memory.
Mind consists of specific modules.
Modules → The section of the brain,each which is responsible for particular cognitive operation.
The brain as the organ of the mind:
Franz Joseph Gall:
He created the term phrenology to study the shape,size and protrusions of the cranium in an
attempt to discover the relation of parts of the brain to various mental activities and abilities.
This argue reduces to three 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 in the brain responsible for these differences!
✤ Not everyone has taken a strong localization of function position?
It simply means that there is a strict one to one correspondence between specific cognitive
functions and specific parts of the brain.
Ablation →Amethod whereby parts of the cortex of an animal are destroyed the results
Conclusion of ablation study:
Mental process are not due to the independent activities of individual parts of the brain ,but to the
activities of the brain as a whole and that it would appear best and most scientific that we should
not adhere to any of the phrenological system.
Study of the effects of ablation of the frontal roots in rats(1890) →
The technique works by making small holes in the animal’s skull rather than opening up the
skull,and determine by later histology precisely where the lesions had occurred.
then they could determine the effect of such lesions on the relation of a simple learned maze
He observed that the ability of rats to learn or remember such tasks as finding their ways through
mazes of different levels of difficulty and found that performance in simple mazes was not
greatly affected by brain damage,rather performance declined as the difficulty of the task
increased and or the amount of brain damage increased.
Laws of mass action → Learning and memory depend on the total mass of brain tissue remaining
rather than the properties of individual cells. Laws of equipotentiality → Even though some areas of the cortex are specialized for certain
tasks,within limits any part of an area can do the job of any other part of that area.
The relation between mind and brain:
It is very important to distinguish between mind and consciousness.
Mind is the broader concept.
• Interactionism → This believes linked to Descartes who believed that mind and body are two
separated substances that interact with and influence each other.
Descartes even postulated a site in the centre of the brain the pineal gland_at which he supposes
this interaction take place.
• Epiphenomenalism → maintains that the mind is simply a by product of brain processes and
has no causal role in determining behavior.
T.H Huxley :Consciousness is to the brain as the steam to steam whistle is a coal powered
locomotive..U can not find out things about the brain by studying what goes in people’s mind.
they believed that consciousness is irrelevant to an understanding of the behavior.
• Parallelism → G.T Fechner.
He studies the relationships between the external world and the mind and brain have not lost any
of their relevance.
Mind and brain are two aspects of the same reality.
• Isomorphism →Mental events and neural events share the same structure.
Wolfgang Köhler :
Gestalt means “configuration “,so gestalt psychologists argues that consciousness does not
consist simply of one event after another,but tends to be organized into a coherent whole.
sone still maintain that this is a fundamental property of consciousness.In fact it states that the
experience and its corresponding brain share the same process.
Difference between parallelism and Isomorphism ?
It is that the latter requires more than a simple point-for point correspondence between mental
events and brain events.
When you focused on the cube namedABCD,then the face seems to be in foreground.
However the figure can reverse itself with the labelled EFGH.
External stimulus in necker cube is always constant but the internal subjective experiences
Methods in cognitive neuroscience: Animal Models:
Human brain is largely inaccessible to the invasive approaches allowed by animal
models,including experimental brain lesions and single cell multiple unit recording.
The problem with tis technique is that the homologous parts are pretty difficult to identify across
species and the specializations of different animals leads to large differences in their
neuroanatomy and neurophysiology.
Note →Much of rat brain is dedicated to the olfactory input and much of the human brain is