Quiz 1 Flashcards
Phenotypic Plasticity
The individual’s capacity to develop into more than one phenotype.
*the way that genetic makeup interacts with environment to elicit a specific phenotype from a large range of possibilities,
Neuroplasticity
The nervous system’s potential for physical or chemical change that enhances its adaptability to environmental change and its ability to compensate for injury.
The brain stems includes what brain structures?
Medulla
Pons
Midbrain
Anatomical vs Functional Organization of Nervous System
Pg 36 in textbook
Brainstem contains neurons that regulate….
- Respiration, cardiovascular activity, consciousness, alertness
- reflexes, simple behaviors mediated by cranial nerves
- Tracts involving cortex & cerebellum for posture, smoothness of muscle movements, muscle tone
Reticular Activating System
- neurons located throughout the brainstem
- activates diencephalon & neocortex for arousal from sleep
- injury leads to problems with arousal, alertness and even coma
Pons
- bridge between cerebellum and rest of brain
- fibers connecting cerebral cortex w/ cerebellum to modulate motor impulses by associating postural and kinesthetic information.
- lesions here (or cerebellum) may cause “cerebellar dysfunction”
Locus Coeruleus
- nucleus in the Pons
- where Norepinephrine is synthesized
- projects to entire cortex
- activates cortex for alertness, responding to novel stimuli, responding to stressful stimuli (especially fear)
- at times, produces positive feelings of reward, helps maintain emotional tone, inhibits pain
Raphe Nuclei
- located from medulla through midbrain
- releases serotonin to the rest of the brain (mood/anxiety disorders)
- also projects to spinal cord to modulate reflexes (including sexual) and pain (less that norepinephrine)
Substantial Nigra
- origin of dopaminergic pathway primarily to striatum of the basal ganglia (nigrostriatal pathway)
- Parkinson’s disease occurs when 90% of DA cells die here
Ventral Tegmental Area
-dopaminergic neurons that project to:
-limbic system, including nucleus accumbens (Mesolithic
pathway)
-reward system
-psychosis when hyperactive
-cortex
-helps to promote optimal attention, cognition, positive
mood
-negative Sxs of schizophrenia when hypoactive
Mesocephalic portion of reticular formation…
…is particularly critical for cortical activation
Cerebellum
- components: cerebral cortex, subcortical nuclei, cerebellar cortex
- subconscious control of complex movement, posture, muscle tone, gait, visuomotor coordination
- acquiring/maintaining smooth, coordinated motor skills
- involved in error correction of movements (compares intended movement w/ actual movement so that next movement is more accurate)
- ataxia: loss of coordination, balance caused by cerebellar dysfunction, alcohol intoxication and as side effect of some drugs
Cerebellum may also have a role in…
- fluency of ideas, perceptions
- prepares neural systems so they are timed properly & faster
- lesions may disrupt selective attention, visiospatial abilities, memory & habit formation, executive functioning (e.g. Abstract reasoning, verbal fluency, & word generation, planning, time judgment), and emotional modulation
- primarily slow in above functions
Behavioral neuroscience
- study of brain-behavior relationships, how brain function relates to thoughts, emotions and behavior
- biological foundations of behavior
- neuropsychology- study of above in humans
Benefits of Clinical Neuropsychology
- research, especially when neuropsych tests are combined w/ neuroimaging
- diagnosis - strengths and weaknesses of individ. pt.
- pt. care and planning
- treatment/rehabilitation
- forensic evaluation
Thinking “outside the box”
- realizing that ct may suffer from multiple disorders
- realizing that a dx should be changed;not getting “locked” into a particular dx
Rostral-Caudal Axis (longitudinal, neuroaxis)
Long axis of body from nose to tail
Dorsal-Ventral Axis
Perpendicular to longitudinal axis from back to front or abdomen
Other terms used in brain
- “Posterior” synonymous with “dorsal”
- “Anterior” synonymous with “ventral”
- In brain, “superior” used for “dorsal” and “inferior” used for “ventral”
Planes of Brain
- horizontal: parallel to longitudinal axis from one side to other (splits to dorsal/ventral portions)
- transverse/coronal: perpendicular to longitudinal axis between dorsal and ventral surfaces (splits to anterior/posterior sections)
- sagittal: parallel to longitudinal axis and midline from dorsal and ventral surfaces (splits to left/right sections)
- midsagittal: midline, divides into symmetrical halves
- parasagittal: off the midline to the side
Ipsilateral
Contralateral
- ipsilateral: on the same side
- contralateral: on opposite side
Afferent
Efferent
- afferent: infor coming into brain or part of brain
- efferent: information leaving brain or part of brain
Nerve
Tract
Nucleus
- nerve: bundle of axons outside CNS
- tract: bundle of axons inside CNS
- nucleus: cluster of cell bodies inside CNS (in gross anatomy)
- where DNA located
- ganglion: a cluster of cell bodies outside CNS
Single Cell Microelectrode
- placed on single neurons, gives insight into function
- single neuron that responds only to:
- head direction
- line segments with certain orientation
- specific human face
- single neuron that responds only to:
Electrical cortical stimulation mapping
- provides insights, but is invasive and usually limited to animals &surgical pts.
- example- when certain areas are stimulated olfactory sensations are experienced
Wada test
Amobarbital injected into cartoid artery disrupts ipsilateral cognitive functioning (usually language is tested)
Electroencephalography (EEG)
-measures graded potentials in dendrites
-advantages;
-excellent temporal resolution
-can be performed in office or clinic, relatively less expensive
-useful for dxing seizures, sleep dis., depth of anesthesia, attn
def.
-disadvantages
-much less spatial resolution (knowing source of various waves)
-cannot assess subcortical structures or all cortical activity
Quantitative Electroencephalogram (qEEG)
-data is quantified, compared statistically to age-appropriate normative database
-advantages
-provides more precise info about activity, including source
-accepted procedure for evaluating TBI in military/VA hospitals
-significant literature relating qEEG patterns tipsy historic/med
disorders
-disadvantages:
-must be used with perspective
-somewhat controversial for clinical use
Event-Related Potentials (ERP)/Evoke Response Potential
- brief changes in EEG response to a discrete sensory stimulus
- repeated stimulation w/ averaging allows for pattern identification & canceling out of unrelated activity
- use of comps can create brain maps & provide insight into:
- areas that process certain stimuli
- sequence of processing
- maturation, compensation after injury, aging
Magnetoencephalography (MEG)
- magnetic fields created surrounding electrical currents
- much better resolution than EEG or qEEG due to less distortion
- better source localization
- more expensive than EEG or QEEG
- only used in research currently, are only a few machines
Computed topography (CT)
Advantages -used mainly in ER -good for imaging bone, TBI, stroke Disadvantages -x-ray exposure -less spatial & temporal resolution than other techniques
Magnetic Resonance Imaging (MRI)
Advantages
-excellent spatial resolution & contrast
-no exposure to x-rays or radioisotopes
-can answer different referral questions by manipulating
parameters
Disadvantages
-pts w/ ferromagnetic materials in body cannot be imaged
-hard for pts w/ claustrophobia
*different protocols produce different things
Position emission tomography
-oxygen or glucose are labeled and then uptake in tissues is measured
-active areas use more oxy and gluc
Advantages
-measures function; used extensively in research
-useful for diagnosing earlyneurodegenerative diseases
Disadvantages
-must be near cyclotron, but these are more common and less expensive currently
Functional MRI (fMRI)
- measures changes in blood-oxygen level dependent signal (BOLD) - a differential measure of oxyhemoglobin vs deoxyhemoglobin after O2 has been used by active cells
- more active metabolism causes greater signal
Advantages
-no radioactive isotopes required, excellent spatial and good temporal resolution.
Disadvantages
- both PET and fMRI have disadvantage of requiring relatively simple tasks compared to complexity of everyday tasks
- neuropsychological tests and knowledge are critical for good experiments using these techniques
Single-Proton Emission Computed Tomography (SPECT)
Advantage
-less expensive & useful for finding sourced seizure onset
Disadvantage
-poorer resolution that PET
-some databases are proprietary and can be controversial
