PSYC 2: Biological Foundations - Fall 2012 - Professor Claffey

Notes: Organization

Version:
10/30/12 - original version

Anatomy of the Nervous System

Content covered in Hans's lecture: CNS & PNS Directions/Planes Protection Spinal Cord -Encephalonic divisions ( mnemonic: "Start at the Top with T, then alphabetically")

Cerebral cortex

Cortical layers

2-4 mm thick with white matter underneath cortex has layers that differ in neuron organization some layers consist mostly of:     _________________ from _____________neurons__          signals arriving from other areas of the brain (__________)     ____________________         densely packed neurons with many synapses (_____________)     __________________ of neurons whose         axons project to other cortical areas (__________________)

Occipital Lobe

Parietal Lobe

Temporal Lobe

Frontal Lobe

Subcortical Structures

"subcortical" is everything under the cortex (the very outer surface)
includes areas introduced above: thalamus, hypothalamus, medulla, pons, cerebellum
includes the limbic system (more detail in Unit: Cognition) & basal ganglia (more detail in Motor System below)

Limbic system

circles the thalamus (limbic is Greek for ring) regulates the four Fs of behavior:    fighting, fleeing, feeding, and ______________ Areas ________________     declarative memory         knowledge that can be declared as oppose to procedural memory ________________     (Greek: almond)     emotional learning, fear & aggressive behaviors

Basal ganglia

To be covered in Motor System of this unit

Motor System

Optional TED Talk - Daniel Wolpert: The real reason for brains (first 2:30 is most relevant, but good stuff after)
   http://www.ted.com/talks/daniel_wolpert_the_real_reason_for_brains.html

Overview
    Responsible for controlling our ________________/skeletal muscle

    Capable of extensive ________________ and ________________

    Requires extensive somatosensory ________________

Pathways

Upper Motor Neurons Cell bodies in primary motor cortex Travel down the spinal cord Lower Motor Neurons Synapse onto muscles - neuromuscular junctions Their action potentials cause muscles to contract

Dorsolateral Pathway

Necessary for ____________________________
Controls the distal muscles (e.g. hands, wrists, feet)
Axons go to only one specific segment of the spine
Lesions cause problems with fine movement (like moving some fingers but not others)

Ventromedial Pathway

Necessary for ________________ and "anti-gravity"
Controls the proximal muscles (e.g. the trunk, neck, chest)
Axons go to many segments of the spine
Lesions cause problems with posture, sitting up, orienting

Brain Areas

Primary Motor Cortex

Role: Main source of output signals to control muscles Input: secondary/supplementary motor areas &    somatosensory cortex Output: spinal cord (motor pathways) Similar to somatosensory cortex     Organized somatotopically     Body regions with more refined control (hands, mouth)         have larger representations Electrical stimulation causes:     Old view:          simple, single muscle contractions     Recent view:    stereotypical, sometime multi-muscle                                 movements                             movement towards a given endpoint                                 regardless of starting position

Secondary Motor Cortex

Role: Planning and coordinating complex movements
Input: dorsolateral prefrontal cortex
Output: primary motor cortex

Includes: supplementary motor area and premotor area

Dorsolateral Prefrontal Cortex (DLPFC)

Role: ________________ which movement to make Input: Posterior parietal Output: Secondary motor areas DLPFC is involved in far more than motor control     Responsible for higher cognitive functions:         working memory, rules, prediction

Posterior Parietal Cortex

(previously introduced in Unit: Sensation)
Role: Representing sense of body and space
Input: sensory systems
Output: dorsolateral prefrontal cortex (DLPFC)

Damage here can cause problems with voluntary movement (though not habitual/automatic movement)

Basal Ganglia

Role: Suppress ____________________________ action Input: cortex Output: cortex via thalamus Serves as the gateway for selecting movement    It is as though the cortex is "proposing" many    different actions and the basal ganglia selects    only one May also select ______________ and ________________ decisions

Cerebellum

Role: Motor learning and fine coordination
Input: Primary/secondary motor, sensory systems
Output: Primary/secondary motor

Receives a copy of the motor command, compares to desired output, makes small adjustments
Also the site of some motor learning (what people call "muscle memory")

Learning

Reflexes

There are sensory neurons that synapse directly on lower motor neurons Capable of producing movement without the brain Advantages: ________________ and ________________ Respond to temperature, joint displacement, pressure

Lateralization

________________ - function is more dependent on one hemisphere (left/right) than the other
contralateral - across/different sides
ipsilateral - same side

Lateralization

________________
    problems with speech
    typically patients with aphasia have damage to ________________ hemisphere
    handedness
        right handed people almost always have language in left hemisphere
        left handed people usually have language in the left hemisphere

Source: mybrainnotes.com/memory-language-brain.html

Fun Facts (will not be tested) Paul Broca & Carl Wernicke  - physicians in 1800's  - performed autopsies on people with aphasia  - noticed the reliability of damage to left hemisphere  - earliest evidence for lateralization in the brain Wada Test     anesthetize one hemisphere of the brain at a time     can impair speech in conscious subjects     used to localize language before brain surgery Optional videos: Broca's aphasia - old, recent Wernicke's aphasia - old

other capabilities
    findings of lateralization for: reading, faces, emotions, music, math, spatial reasoning, details/gist
    often exaggerated in the popular media
    differences can be minor and/or unreliable from person to person
    after damage, other hemisphere can sometimes compensate or develop
    expertise can exaggerate differences

Split-brain patients

 ____________________________ can be surgically cut
    done either experimentally (animals) or to treat epilepsy (humans)
    effects in human patients are obvious/subtle

In cats (Myers & Sperry)

Full description of the experiment on P415-416 (8th ed.) Four different treatments in the experiment: A. no surgery B. cut the optic chiasm C. cut the corpus callosum D. cut both optic chiasm and corpus callosum One hemisphere learned as fast as both hemispheres still connected Learning could be transferred across corpus callosum

In humans (Gazzaniga)

Source: brainmind.com/Brain3.html

Patients have corpus callosum cut as epilepsy treatment Different objects/words could be presented to each hemisphere Person would answer different depending on which hemisphere was responding (remember: language only on left) 2 hemispheres are functioning independently within a person Videos: Gazzaniga w/ Alan Alda, Other

Development

How do we get from embryo to mature adult brain?

Neural Development

Timing of Development

Critical Periods

The effect of depriving one eye on the development of the visual cortex

Principles