Chapter 2: The Neural Basis for Cognition Flashcards
What are the basic parts of the neuron?
dendrites - detects the incoming signals; neuron receives information
cell body - contains the nucleus and the cellular machinery
axon - transmits signals to other neurons
Do neurons touch each other?
no they have a space between them known as a synapse or synaptic cleft
What is a touch neuron?
it has a touch receptor in place of a cell body
-responds to pressure on the skin
What was done in the measuring the speed of neural impulse in class lab?
use response time subtraction method and compare time between pressure on the wrist and pressure on the shoulder and do subtraction and isolate tom between wrist and shoulder and see how it takes for 0.60m different and time for how long neuronal communication takes to travel from one point to another
speed = distance/time difference
distance = number of people * 0.6m * 10 cycles
In the neural impulse lab done in class what parts of the nervous system were used?
brain - receives and processes sensory information and initiates responses stores memories generates thoughts and emotions
spinal cord - conducts signals to and from the brain and controls the reflex activities
sensory neurons - sensory organs to the cns
What are the three parts of the brain and what do they do?
hindbrain - responsible for automatic processes like breathing
midbrain - connects the hindbrain and forebrain
forebrain - responsible for congition like decision making, memory, speaking
What are the two hemispheres of the brain and what are they divided into?
-right and left hemisphere
-outside lobes are the frontal parietal and occipital and temporal
-internal lobe is the limbic system which is emotional processing and memory
What does the hypothalamus do?
regulate body functions
What does the basal ganglia do?
movement and reward
What does the thalamus do?
sensory gateway
What does the hippocampus do?
memory
What is the localization of function?
think there is one to one corresponsecen of localization and function
What is the language production area?
brocas area - frontal lobe
What is the language comprehension area?
wernickes area - temporal lobe
What are some if the different networks of the brain that support processes like memory, language and face object recongitiion, etc..?
-central executive (cen)
-salience (sn)
-default mode network (dmn)
What are some neuroscience methods?
-lesions - give us insight into causally necessary function of brain structures
-lesions are not well localized
-limited by patient population
-neuroimaging methods - provide correlation between brain structure or function and physiological processes
-allow us to study the whole brain
-can not infer causality
-transcranial magnetic stimuluation
-can be used to test causal relationship hypothesized based on neuroimaging finding
-guided by imaging
What are some examples of lesion studies?
-louis victor leborgne tan patient of broca
-lost abiltiy to speak at 30
-brocca’s area - speech production
-hm
-suffered from epilepsy, hippocampus surgically removed, could not form new memories
-wernicke
-patients can speak
-speech fluent but not informational
-800,000 pateints a year in the US diagnosed with stroke
What is structural neuroimaging and some techniques?
-shape, size, position of structure in the brain
-computerized axial tomography CT scans
-rely in 3d xray of brain
-side effect radiation
-spatial resolution 0.5 mm - good
-magnetic resonance imaging (MRI) scans
-uses powerful magnetic fields and radio frequency pulses
-will effect metal in body
-spatial resolution 1-2mm - not as good as CT
What is functional neuroimaging and some techniques?
-positron emission tomography PET scans
-uses a radioactuve tracer (proteins or glucose bind to the tracer so that areas with more activity like glucose show)
-resolution (5-10mm)
-FMRI
-uses magnetic fields and radio frequency pulses
-based on the finding that areas of the brain that are more active use more oxygen —> identify activity by tracing oxygenated blood flow
-resolution 2-3mm
-EEG
-fastest temporal resolution
-poor spatial resolution at least 10 times worse than fmri and pet
-measures changes in the electrical field in the surface of the brain and look at event related potentials to see a change in the electrical field related to an event
What are the strengths and limitations of eeg, pet, fmri, ct, and mri?
eeg
pro - good at temporal location of neural activity
con - bad at spatial location of neural activity
pet and fmri
pro - good at spatial location of neural activity
con - bad at temporal location of neural activity
ct and mri
pro - detect brain structures
con - do not detect activity
-researchers can overcome these limitations by combining activity
What is TMS?
-a brief electrical pulse of rapidly alternating current passed through a coil of wire generates a strong time varying magnetic field
-the induced magnetic field pulse penetrates the scalp and skull reaching the underlying brain tissue
-the rate if change in this magnetic field in turn induces a secondary electrical current within the brain tissue
-tms represents a method of electrodeless electrical stimulation whereby the magnetic component is responsible for bridging the transition between electric current passed in the coil and current induced in the brain
How is tms used in brian mapping?
-tms pulse appropriately delivered in space and time can temporarily disrupt cortical function in a given area
-allows to identify which parts of the identified network are necessary for specific function
-can refine and confirm hypotheses drawn on neuroimaging findings
What did wang et al do in their study with hippocampal network activity and memory and TMS?
-Have significant assessment and functional mri - stimulation of this network only helps with memory not otehr cognitive parts of the Brian so they tested language attention executive function so want to localize teh function of this network
-looked for synchronization in the brain in regards to functional connectvooty this means this parts of the brain work synchronized
-Have a condition where different areas of the Brian have stimulation
-negative control - uses motor cortex as stimulation site - found no effect on the network in question nor memory performance
-results - remember face with word and see network got more synchronized and did better on memory not other control tests via the stimulation
