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Ok…to the brain! Gross Anatomy of the brain: Many ways to organize the CNS

Ok…to the brain! Gross Anatomy of the brain: Many ways to organize the CNS. Here’s a good one!. BRAINSTEM/ HINDBRAIN. Bainstem (Medulla) critical functions. Ascending and Descending Fiber Tracts All parasympathetic tone HR Temp BP Etc. Brainstem: The “Reticular activating system”.

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Ok…to the brain! Gross Anatomy of the brain: Many ways to organize the CNS

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  1. Ok…to the brain! Gross Anatomy of the brain:Many ways to organize the CNS

  2. Here’s a good one!

  3. BRAINSTEM/ HINDBRAIN

  4. Bainstem (Medulla) critical functions • Ascending and Descending Fiber Tracts • All parasympathetic tone • HR • Temp • BP • Etc

  5. Brainstem:The “Reticular activating system” Many tiny brain nuclei collectively involved in modulation of arousal; The reticular formation is a comprehensive network of nerves that is found in the central area of the brainstem. The functions of the formation involve many of the essential functions of the body, such as the ability to obtain recuperative sleep, sexual arousal, and the ability to focus on tasks without being easily distracted. All in all, reticular formation function is believed by some researchers to be involved with at least 25 behaviors and functions that are considered essential for the health and continued existence of each individual.

  6. The RAS- Locus Coereleus

  7. RAS- the Raphe Nucleus Raphe Nucleus – High in Serotonin (5HT) Modulation of mood, sleep states, dreaming

  8. BRAINSTEM-Pons and Cerebellum

  9. Behavioral Functions of the Cerebellum • Direction • Amplitude • Force • Timing • Posture • Motor learning/speech

  10. Midbrain Major structures of interest: Substantia nigra- projects to striatum (high Dopamine (DA) content) Peri-aqueductal grey- modulation of pain Ventral tegmental area- projects to nucleus accumbens ( high in DA content)

  11. Midbrain- The ventral tegmental area (VTA)

  12. VTA to Nucleus Accumbens: The Mesolimbic Dopamine pathway

  13. Diencephalon Thalamus, Hypothalamus and Pituitary gland

  14. The Thalamus Relays sensory information to the cortex

  15. The Hypothalamus -rostral and slightly inferior to the thalamus. - Involved in modulation of the 4 F’s

  16. Forebrain • (Telencephalon) • Cortex • Basal ganglia • Limbic System

  17. Basal Ganglia • Neostriatum • Caudate nucleus and putamen • Globus Pallidus • Substantia nigra

  18. Nigro-striatal system The substantia nigra sends DA axons to the striatum

  19. Nigro-striatal CCT Functions • Parkinsons’ Slowness of movement (bradykinesia) Stiffness (rigidity) Tremor Loss of balance (postural instability) Speech and facial expression

  20. **Difficulty in initiating Movement

  21. GLOBUS PALLIDUS

  22. Striatal-Pallidal CCT functions? • Huntingtons • Tourettes’ -

  23. Tourettes • Tourette syndrome (TS) is a neurological disorder characterized by repetitive, stereotyped, involuntary movements and vocalizations called tics. The early symptoms of TS are almost always noticed first in childhood, with the average onset between the ages of 7 and 10 years. TS occurs in people from all ethnic groups; males are affected about three to four times more often than females. It is estimated that 200,000 Americans have the most severe form of TS, and as many as one in 100 exhibit milder and less complex symptoms such as chronic motor or vocal tics or transient tics of childhood. Although TS can be a chronic condition with symptoms lasting a lifetime, most people with the condition experience their worst symptoms in their early teens, with improvement occurring in the late teens and continuing into adulthood.

  24. Tics are classified as either simple or complex. Simple motor tics are sudden, brief, repetitive movements that involve a limited number of muscle groups. Some of the more common simple tics include eye blinking and other vision irregularities, facial grimacing, shoulder shrugging, and head or shoulder jerking. Simple vocalizations might include repetitive throat-clearing, sniffing, or grunting sounds. Complex tics are distinct, coordinated patterns of movements involving several muscle groups. Complex motor tics might include facial grimacing combined with a head twist and a shoulder shrug. Other complex motor tics may actually appear purposeful, including sniffing or touching objects, hopping, jumping, bending, or twisting. Simple vocal tics may include throat-clearing, sniffing/snorting, grunting, or barking. More complex vocal tics include words or phrases. Perhaps the most dramatic and disabling tics include motor movements that result in self-harm such as punching oneself in the face or vocal tics including coprolalia (uttering swear words) or echolalia (repeating the words or phrases of others). Most patients experience peak tic severity before the mid-teen years with improvement for the majority of patients in the late teen years and early adulthood. Approximately 10 percent of those affected have a progressive or disabling course that lasts into adulthood.

  25. Tics are involuntary. They are brief, repetitive movements, which are either motor such as blinking or head jerking, or vocal such as throat clearing.

  26. LIMBIC SYSTEM • Basal forebrain • Affective responses • Impulsive…low consciousness • Many structures • Amygdala • Hippocampus • Septum/ nucleus accumbens- will be discussed later

  27. Amygdala: general emotional significance of environmental stimuli • evaluate the significance of stimuli and generate emotional responses • generate hormonal secretions and autonomic reactions that accompany strong emotions

  28. CEREBRAL CORTEX • Wrinkled • Thin • Layered • Interconnected • Plastic

  29. Major regions of CTX

  30. Corpus collosum

  31. Hemispheres

  32. Almost all of Right handers and about 70% of left handers show these kinds of functional asymmetries

  33. LOBES

  34. OCCIPITAL LOBE The primary Visual Cortex -functional blindness -Visual agnosias

  35. TEMPORAL LOBES

  36. Temporal lobe damage may result in any number of problems including any of these syndromes Functional deafness -Anomias • -Aprosodia • -Werniches’ syndrome

  37. Parietal Lobes Primary somatosensory cortex

  38. The sensory homunculus and somatotopic organization Primary somatosensory cortex damage may produce -somatasagnosias -neglect -anosagnosia

  39. FRONTAL LOBES

  40. 1st -Frontal lobes and speech • Broca’s aphasia • Werniche’s aphasia (temporal lobe to frontal lobe circuits)

  41. What about the rest of the frontal lobe?-Phineas Gage

  42. rod

  43. Frontal Parietal Occipital Temporal Brain-Based Theory of Emotions • Frontal lobes • influence people’s conscious emotional feelings and ability to act in planned ways based on feelings (e.g., effects of prefrontal lobotomy) • Some scientists contend that the prefrontal cortex normally acts as a brake that can suppress urges or impulses by communicating with other brain areas that mediate fear and aggression, such as the amygdala.

  44. General frontal Lobe functions Awareness Judgment , planning and anticipation Personality Conscious emotions Organization and mental flexibility Attention and concentration Initiation and inhibition of behavior

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