Cognitive Neuroscience

Chapter 2

To Do List… Neuroanatomy (just the basics)

Methods of Investigation Behavioral studies Neuroimaging

Hemispheric Specialization What is lateralized? Split-brain patients “Normals”

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Important Brain Structures Brainstem (basic functions)

Medulla Automatic functions Heart rate, respiration

Pons Sleeping, dreaming

Reticular Activating System (RAS) Arousal Extends into the center of the brain

Cerebellum Movement, balance Analyzing sensory info and language comprehension

Important Brain Structures Thalamus

Traffic officer Sensory relay station, attentional gate

Hypothalamus Eating, drinking, sex, temperature control Coordinates brain and hormonal systems

Brain Anatomy

Important Brain Structures Limbic System

Hippocampus Encoding long term memories Gateway to memory

Amygdala Emotions (fear and anger) initial response to

sensory information Enhances memory

Important Brain Structures Cortex

Frontal Lobe Motor Cortex * Planning, goal setting, emotional control

Temporal Lobe Auditory Cortex (hearing) Language, Music

Parietal Lobe Somatosensory Cortex (touch) *

Occipital Lobe Visual Cortex

Methods of Investigation Lesions

Animals

Patients Stroke Tumors Head injury

Stroke

Tumor

Head Injury

Phineas Gage Phineas was a railroad

construction foreman (1848)

An explosion forced a steel rod through his head

He was “…no longer Gage…”

Lost his job, worked as a sideshow exhibit

Dissociation Dissociation occurs when a patient has

brain damage leading to some cognitive deficit, but other cognitive abilities are preserved

E.g., H.M. has no ability to store LTM, but his STM is completely normal LTM and STM must be different systems

Methods of Investigation Direct Stimulation

Animals Patients

Imaging Brain Function Electrophysiology

Electroencephalograms (EEGs)– passive recording from multiple electrodes

Event-Related Potentials (ERPs)– measures response to a specific stimulus

Measuring ERPs in an infant

EEG

Imaging Brain Function CT

Computerized Tomography X-ray

MRI Magnetic Resonance Imaging

CT scan demonstrating enlargement of the ventricles in a patient with schizophrenia

Magnetic Resonance Imaging (MRI)

Method for studying body and brain tissue

Magnetic fields align hydrogen atoms

When field is removed, molecules release energy as radio waves

Computer calculates tissue density from radio waves

Provides clear, 3D images

MRI scanning magnet

Imaging Brain Function PET

Positron Emission Tomography

fMRI Functional Magnetic Resonance Imaging

Positron Emission Tomography (PET) Analysis of brain activity, using injections

of glucose with a radioactive tracer

Active areas use more glucose and sensors detect radioactivity

Different tasks show distinct patterns (bright spots)

PET scanning

PET image-red areas aremost active

fMRI (oxygenated blood flows to active areas)

The two hemispheres of the brain are connected by a band of fibers called the corpus callosum

Hemispheric Specialization Different brain functions tend* to rely

more heavily on one hemisphere or the other

THERE ARE NO LEFT-BRAINED OR RIGHT-BRAINED PEOPLE Over exaggeration and simplification Any intelligent behavior requires both

hemispheres to work together

Hemispheric Specialization Left

Right side of body Linguistics Fine motor control Fine details

Right Left side of body Music Emotion Spatial Processing Big Picture

Split-Brain Patients Severed corpus callosum to stop epileptic

seizures No obvious problems at first Laboratory testing revealed some

problems Remember

Left hand projects to right hemisphere Right hand projects to left hemisphere Only the left hemisphere can talk

Left visual field projects to righthemisphere

Right visual fieldprojects to lefthemisphere

Split-Brain Patients This is confusing

Let me help … Movie Time!