3 primary divisions: –Forebrain cortex (folded stuff) limbic system, etc (stuff around brain stem)...
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Transcript of 3 primary divisions: –Forebrain cortex (folded stuff) limbic system, etc (stuff around brain stem)...
• 3 primary divisions:– Forebrain
• cortex (folded stuff)• limbic system, etc (stuff around brain stem)
– Midbrain (top of brainstem)
– Hindbrain (bottom of brainstem + cerebellum)
The Brain
Hindbrain
Medulla
Pons
Cerebellum
http://www-unix.oit.umass.edu/~psyc335c/lectures/hindbrain.gif
Pons
MedullaCerebellum
Medulla:Controls vital reflexes: breathing, heart rate, vomiting, salivation, coughing, sneezing
- Via cranial nerves
Damage to medulla can be fatal
Large doses of opiates can be fatal b/c suppress activity of medulla…why…?...b/c receptors there!
Pons:Also has cranial nerves
Location of axon decussation (where axons cross from one side of the brain to the other…so left brain controls right body and vice versa)
Reticular formation: motor control, arousal, consciousness
Midbrain:Cerebral aqueduct
More cranial nerves
Superior colliculus (visual info)
Inferior colliculus (auditory info)
Substantia nigra: dopamine-producing cells, structure that is lost in Parkinson’s Disease
http://en.wikipedia.org/wiki/Midbrain
BrainstemMedulla
Pons
Midbrain
Some forebrain structures
Senses: Information comes in the cranial nerves and eventually ends up in the cortex
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Olfactory nerve:
Smell
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Optic nerve:
Vision
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Occulomotor nerve:
Eye movement, pupil constriction
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Trochlear nerve:
Eye movement
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Trigeminal nerve:
Skin senses from face
Jaw muscles for chewing and swallowing (muscles of mastication)
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Abducens nerve:
Eye movements
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Facial nerve:
Taste
Facial expressions
Crying
Salivation
Dilation of head’s blood vessels
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Acoustic nerve:
Aka vestibulocochlear or statoacoustic
Hearing
Equilibrium
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Glossopharyngeal nerve:
Taste
Swallowing
Salivation
Throat movements during speech
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Vagus nerve:
Sensation from neck and thorax
Control of throat, esophagus, larynx
Parasympathetic nerves to stomach, intestines, etc
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Spinal accessory nerve:
Aka Accessory nerve
Neck and shoulder movements
Cranial Nerves
http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg
Table 4.4, page 87
Hypoglossal nerve:
Muscles of tongue
Cranial nerve signs help determine the location of a lesion in the brain
• Essential element in clinical neuroanatomy
• Neurological exam: http://www.vhct.org/case1799/neurologic_examination.shtml
• Example: patient is asked to stick out tongue. If the tongue deviates to the left, the lesion involves the nucleus of the left hypoglossal nerve.
Nerve key Nerve Type of function
On Optic Some = sensory
Old Olfactory Say
Olympus Occulomotor Marry = motor
Towering Trochlear Money
Tops Trigeminal But = both (S&M)
A Abducens My
Fin Facial Brother
And Acoustic* Says
German Glossopharyngeal Bad
Viewed Vagus Boys
Some Spinal accessory** Marry
Hops Hypoglossal Money
* Acoustic-vestibulocochlear, stateocochlear
** Spinal accessory = accessory
Forebrain
• Thalamus
• Hypothalamus
• Pituitary gland
• Basal ganglia
• Basal forebrain
• Hippocampus
• Limbic system
Thalamus:
Relay station for all sensory info on its way to brain (except olfactory info)
Many specialized nuclei (ex: LGN, MGN…don’t have to know these!)
Hypothalamus
Communicates with pituitary gland to alter hormone release
Involved in feeding, drinking, temperature regulation, sexual behavior, fighting, arousal (activity level)…4 Fs
Pituitary gland
Endocrine gland (hormone producing)
Attached to base of hypothalamus by stalk
Makes and releases hormones into bloodstream
http://www.uni.edu/walsh/basalganglia-2.jpg
Basal Ganglia
Motor control, but also memory and emotional expression
Lose dopamine neurons in SN Parkinson’s Disease
Lose dopamine neurons in caudate & putamen Huntington’s chorea
thalamus.wustl.edu/ course/cbell6.gif
Don’t memorize image!!! Just understand that this is a very complex system!
http://memorylossonline.com/summer2003/glossary/basalforebrain.jpg
Basal forebrain
Anterior and dorsal to hypothalamus
Important for arousal, wakefulness, attention
Lose cells in nucleus basalis decreased attention & intellect (AD, PD)
http://www.hermes-press.com/Perennial_Tradition/hippocampus.gif
Hippocampus
Memory formation
HM: temporal lobes removed for intractable epilepsy no longer formed new memories
http://www.umassmed.edu/bnri/graphics/crusiofig1.gif
important for motivated & emotional behaviors (eating, drinking, sexual activity, aggressive behavior)
Limbic System
Ventricles
http://mywebpages.comcast.net/epollak/PSY255_pix/ventricles.PNG
Contain cerebrospinal fluid (CSF)
CSF reabsorbed into blood vessels, so continuous turnover
Protective
Reservoir for hormones, nutrients
Ventricle size can indicate problems
• Enlarged ventricles as in Alzheimer’s patients (cell loss).
• Lack of ventricles due to tumors etc.
Cortex• 2 hemispheres
– Communicate via corpus callosum & anterior commisure
• 4 lobes
http://pegasus.cc.ucf.edu/~Brainmd1/brmodelc.gif
http://www.urmc.rochester.edu/neuroslides/slides/slide201.jpghttp://trc.ucdavis.edu/mjguinan/apc100/modules/Nervous/grosscns/images/brain10.jpg
6 laminae (layers of cells)
The lobes of the cortex• Frontal
– Thinking– Prefrontal cortex
• Planning• Working memory• Socially appropriate
behavior• Delayed-response
task • Lobotomies
– Primary motor cortex
• Broca’s aphasia
The lobes of the cortex
• Parietal– Sensing
• Primary sensory cortex
Homunculus
The lobes of the cortex• Temporal
– Spoken language comprehension
• Wernike’s aphasia
– Hearing– Vision
• Movement perception
• Face recognition
– Emotional motivational behavior
The lobes of the cortex
• Occipital – Vision
• Primary visual cortex
• Damage causes “cortical blindness”
Evolution of Gene Related to Brain's Growth
• A gene that helps determine the size of the human brain has been under intense Darwinian pressure in the last few million years.
• It has changed its structure 15 times since humans and chimps separated from their common ancestor.
• Evolution has been particularly intense in the five million years since humans split from chimpanzees
Changes in the architecture of the ASPM protein over the last 18 million years are correlated with a steady increase in the size of the cerebral cortex (2002) Dr. Bruce T. Lahn at U. Chicago. A disrupted form of this gene was identified as the cause of microcephaly (people born with an abnormally small cerebral cortex).
Functions
• Forebrain– the cool stuff (thinking, perceiving, big part of emotion)
• Midbrain– sensory pathways
• Hindbrain– motor control, reflexes (breathing, heart rate, etc)