The Brain

GABA Weight Loss Ad

The Brain

Phrenology equipotentiality Localization Neuroimagingtechniques

Localization vsEquipotentiality

Brain Structuresand Functions

Left and Right Hemispheres

Cortical Plasticity

The Brain

Development of Localization

Phrenology Gall

Equipotentiality Flourens

Localization Broca

Neuroimaging TechniquesStructural

MRITemporal Resolution

EEG MEG

Spatial Resolution PET SPECT fMRI

W. W. Norton

SPECT

45 y/o - 27 yrs of heavy use

3 packs of cigs and 3 pots of coffee daily

Nicotine and Caffeine Abuse

Localization vsEquipotentiality

Brainstem MIdbrain Forebrain

Brain Structuresand Functions

Left and Right Hemispheres

Cortical Plasticity

The Brain

W. W. Norton

Brainstem

Extension of the spinal cordsurvival programs

breathing swallowing gagging/vomiting

consists of hindbrain and midbrain

Hindbrain

Pons contains part of reticular formation contains large nucleus that relays info

from cortex to cerebellumMedulla

contains part of reticular formation

Hindbrain

Cerebellum performance of coordinated movements integrates visual, auditory, vestibular

and somatosensory info and info about individual muscle movements

motor learning

W. W. Norton

Midbrain

Midbrain helps integrate motor and sensory

information

Reticular Formation (part of the tegmentum) receives sensory info that it projects to

the cortex and basal ganglia sleep and arousal regulation of cardiovascular system,

respiration and skeletal muscle tone sleep

Tectum on top of the midbrain contains:

superior colliculi - part of visual systeminferior colliculi - part of auditory system

orienting head and body to face prominent stimuli (topographic map of space)

Forebrain

Diencephalon hypothalamus thalamus

Telencephalon limbic system basal ganglia cerebral cortex

W. W. Norton

W. W

. No r

ton

Hypothalamus

Controls autonomic nervous system body temperature circadian rhythms blood pressure

controls the endocrine system hormones produced hypothalamus

controls pituitary gland controls hormonal release

Hypothalamus

Organizes behaviour related to survival of the species - the so-called four F’s:

•Fighting

•Feeding

•Fleeing

•Mating

W. W

. No r

ton

Thalamus

Composed of numerous nucleiGateway to the cortex

all sensory info except olfactory controlling general excitability of the

cortex attention/blocking info during sleep

W. W

. No r

ton

Limbic System

Hippocampus learning and memory spatial navigation

Amygdala emotional memories classical learning

associating environmental stimuli with emotion (fear)interpreting emotions conveyed by facial expressions

Basal Ganglia

Consists of caudate nucleus, putamen and globus pallidus

input from cerebral cortexproject to motor centers of brainstemplanning and producing movement

Basal Ganglia

Damage to basal ganglia motor disorders

initiation of planned movement

impaired motor learninghabits

Damage of projections to basal ganglia Parkinson’s disease

W. W

. No r

ton

Frontal Lobe

Primary motor cortex contralateral connects to muscles in

different parts of the bodyMotor Association cortex

planning movementsPrefrontal cortex

Prefrontal Cortex

formulating plans and strategiessequencingflexibility of behaviourcontrol of impulses/self-controlmanagement of interferenceattention judgement/critical thinkingshort-term memory

Damage to Prefrontal Cortex

right frontal lobe - difficulty appreciating humour

socially ineptrule breakingimpulsivedistractiblepoor time management/poor organizationpoor judgement/don’t learn from mistakes

ADD - concentration task

marked decrease in prefrontal and left temporal

regions

underside

Parietal Lobe

Somatosensory cortex info from skin

touchtemperaturepressurepossibly pain (phantom limb)

W. W

. No r

ton

Parietal Lobe

Somatosensory cortex info from skin

touchtemperaturepressurepossibly pain (phantom limb)

posterior parietal lobe visually guided movements hemineglect

Temporal Lobes

Primary auditory cortexauditory comprehension

left hemisphere - language right hemisphere - sounds, melodies,

noises

Occipital Lobes

Primary visual cortexvisual association cortexpathway from visual to parietal cortex

visually guided movementspathway from visual to temporal

cortex object recognition

W. W

. Nor

ton

Marijuana

18 y/o - 3 year history of 4X/wk use

decreased pfc and temporal lobe activity

underside

28 y/o - 10 years of mostly weekend use

decreased pfc and temporal lobe activity

underside

Marijuana

Heroin

39 y/o - 25 yrs of frequent use

front on surface view - marked overall decreased activity

Cocaine

24 y/o - 2 yr of frequent use

top down surface view

multiple holes across cortical surface

Alcohol

38 y/o - 17 years of heavy weekend use

marked overall decreased activity

W. W

. No r

ton

Lateralization of Function

In general: left hemisphere

analyticsequential

right hemispherespatialholistic analysisemotions - facial, tone body language

W. W. Norton

Violinists have more cortical area devoted to the fingers in the right hemisphere than in the left hemisphere. Why?

Synaptic Plasticity

Learning/experience increases spine density