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Notes:

- SyllabusPrereqs – Psych 260 OR 351

Office Hours – 11:00 to 12:00 T THClass Question

Website: http://www.ndsu.nodak.edu/ndsu/pavek/

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“The Development of Neuropsychology”

Human Neuropsychology (486 / 686)Lecture Chapter 1

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Overview

- What is Neuropsychology?- Human Brain- Divisions of the Nervous System- The Brain Hypothesis- The Neuron Hypothesis

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What is Neuropsychology?Neuropsychology

- Scientific study of the relationship between behavior and the brain

- Draws from many disciplines, including anatomy, biology, pharmacology, and philosophy

- Experimental results from neuropsychological investigations can be used to identify traumatic brain injury impairments and vice versa

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What is Neuropsychology?

Two ideas that influence experimental and theoretical investigations of brain function

The Brain Hypothesis:-The brain is the source of

behaviorThe Neuron Hypothesis:

- The unit of brain structure and function is the neuron

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The Human BrainWhat is the brain?

Brain = Old English word for tissue inside the skull

Inner hollow tube filled with cerebrospinal fluid (CSF)

Outer layer of wrinkled tissue known as cerebral cortex

Composed of two symmetrical hemispheres, the right hemisphere and the left hemisphere

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The Human Brain Three Major Divisions of CNS

Forebrain Cerebral CortexPerforms higher functions like thinking, perception and

planning

BrainstemUnderlying tube Performs regulatory and movement producing functions

Spinal CordConnected to brainstem and descends down the backPerforms regulatory and movement producing functions

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Features of the Cortex

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Features of the Cortex Gyri

Folds of the cortex Sucli

Creases between the folds

* Large sulci = fissuresExamples: Longitudinal

Fissure and Lateral Fissure

Four Lobes:- Frontal- Temporal- Parietal- Occipital

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Divisions of the Human Nervous System

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The Brain HypothesisWhat is behavior?

“Patterns in time”Movement of an organism

- cause & function (purposeful?)- complexity & flexibility

How is behavior produced? Brain vs Heart Brain Hypothesis - Alcmaeon of Croton Cardiac Hypothesis - Empedocles of Acragas

Current neuropsychology accepts the brain

hypothesis

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Perspectives on Brain and Behavior  

Aristotle* and Mind   Descartes* and

Dualism Descartes’s Legacy Darwin* and

Materialism   Darwin’s Legacy

Natural selection   Linking Brain

Function to Brain Disease  

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Donald Hebb: “Modern psychology takes completely for granted that behavior and neural function are completely correlated, that one is completely caused by the other. There is no separate soul or life force to stick a finger into the brain now and then and make neural cells do what they would not otherwise. It is quite conceivable that some day the assumption will have to be rejected. But it is important also to see that we have not reached that day yet: the working assumption is a necessary one, and there is no real evidence to oppose it. One cannot logically be a determinist in physics and chemistry and biology, and a mystic in psychology.”

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Experimental Approaches to Brain Function

Localization of Function - different parts of the brain perform different functions- Franz Josef Gall and Johann Casper

Spurzheim• Phrenology

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PhrenologyProblems

Impossible to define and quantify objectivelyFeatures of the skull reveal little about the brain

Historical ImportanceLaid foundation for modern localization of

functionPhrenological map was the precursor for many

maps of the brain

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Localization and Lateralization of Language

Paul Broca*- Broca’s Area: anterior speech region of the brain- Lateralization: Functions can be localized to one side

of the brainTan’s Lesion

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Sequential Programming

and Disconnection

Carl Wernicke*- Aphasic patients

different from Broca’s

- Wernicke’s Area - Posterior speech region, located in the temporal lobe

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Sequential Programming and Disconnection

Importance of Wernicke’s modelIdentified disconnection syndromes

Regions of the brain have different functions but still must interact to work correctly

Identified the left hemisphere as dominant for language

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Loss and Recovery of FunctionPierre Flourens

Removed areas of the cortex of animal brains and studied resulting changes in behavior

FindingsNo specialization for areas of the cortexSpecialization for the brainstemFindings refuted localization of function

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Hierarchical Organization and Distributed Systems in the Brain

Hierarchical OrganizationJohn Hughlings-Jackson*

Each successively higher level of the nervous system controls more complex aspects of behavior

DissolutionReverse of evolutionOccurs after damage to a higher levelBehavior becomes more simple

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The Binding Problem H.M. (Henry Molaison)

The brain analyzes sensory events through multiple channels, yet we have a unified perception of our experiences

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The Split Brain1960s

Neurosurgeons began cutting the corpus callosum to prevent the spread of seizures

Roger Sperry Conducted neuropsychological evaluations on

“split brain” patients to discover how the right and left hemispheres function

Nobel prize in 1981

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Conscious and Unconscious Neural Streams

The case of D.F. Visual form agnosia

Inability to recognize objects by their shapes or see the shape of an object

Able to accurately reach for an objectOptic Ataxia

Can identify the shape of an object Cannot accurately reach for an object

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Neural Streams

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The Neuron Hypothesis

• The unit of brain structure and function is the neuron

- Neurons are discrete- Neurons send an electrical signal - Neurons communicate with each other

via a chemical signal, or a neurotransmitter

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Identifying the NeuronCamillo Golgi*

Proposed the Nerve Net Hypothesis

Santiago Ramón y Cajal* Proposed that

neurons were discrete

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Nervous System Cells

NeuronsAcquire information, process

information, and act on information

Major parts include the cell body, dendrites, and axons

Glia Help neurons, hold them

togetherCarry out supportive

functions

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Relating Electrical Activity in Neurons to Behavior

Luigi GalvaniDiscovered electrical

stimulation caused muscular contraction

Gustav Theodor Fristch and Eduard Hitzig Electrical stimulation of the

cortex in the rabbit and dog to induce movement

Discovered topographic organization in the cortex

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Relating Electrical Activity in Neurons to Behavior

Roberts BartholowFirst to report electrical

stimulation of human cortex in a conscious person

Modern ApproachTranscranial magnetic

stimulation (TMS)

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Connections Between Neurons As the Basis of Learning

Alan Hodgkin and Andrew HuxleyNobel prize in 1963 for discovery of the

electrical signals generated by neuronsCharles Scott Sherrington

First description of the synapseOtto Loewi

Discovered that chemicals carry the message across the synapse

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Connections Between Neurons As the Basis of Learning

Donald Hebb*When cells are activated at the

same time they establish or strengthen the synapse

Hebb or plastic synapses

The brain is plastic and constantly changing

There is ongoing reorganization