Biopsychology Flashcards
What does the nervous system consist of?
The brain and spinal cord.
What is the two main functions of the nervous system?
- To collect, process and respond to environmental information
- To co-ordinate the working of different organs and cells in the body.
What two main subsystems is the nervous system divided into?
- The central nervous system (CNS)
- The peripheral nervous system (PNS)
What is the brains outer layer called?
The cerebral cortex
How thick is the cerebral cortex?
3mm thick.
True or false: the cerebral cortex is only found in mammals
True!
The brain is highly developed in humans and distinguishes our higher mental functions from those of other animals.
Creatures such as jellyfish and sponges do not have a brain.
What is the brain divided into?
Two hemispheres
What is the spinal cord?
An extension of the brain
What is the spinal cord responsible for?
- Passes messages to and from the brain
- Connects nerves to the PNS
- Responsible for reflex actions
What are the subdivisions of the peripheral nervous system?
- The autonomic nervous system
- The somatic nervous system
What is the central nervous system?
Consists of the brain and spinal cord and is the origin of all complex commands and decisions.
What does the PNS do?
Sends information to the CNS from the outside world, and transmits messages from the CNS to muscles and glands in the body.
What does the somatic nervous system do?
Governs muscle movement and receives information from sensory receptors
What does the autonomic nervous system do?
Governs vital functions in the body such as breathing, heart rate, digestion and stress responses: this operates involuntarily and is subdivided into the sympathetic and parasympathetic NS.
What is the autonomic nervous system subdivided into?
- Parasympathetic nervous system
- Sympathetic nervous system
What is the endocrine system made of?
Glands and hormones
What is the master gland?
The pituitary gland: it controls the release of hormones from all the endocrine glands in the body
What is the difference between the endocrine system and the nervous system?
The endocrine system acts more slowly than the nervous system but has very widespread and powerful effects
What is the autonomic nervous system?
A subdivision of the peripheral nervous system that transmits information to and from internal organs. It is ‘autonomic’ as it is INVOLUNTARY.
It governs vital functions in the body such as breathing, heart rate and digestion.
What is the somatic nervous system?
The subdivision of the PNS that governs VOLUNTARY muscle movement and receives information from sensory receptors.
What does the endocrine system consist of?
Consists of glands that produce hormones which are secreted into the blood stream.
What is the ‘master gland’ and what does it do?
The pituitary gland.
It controls the release of hormones from all the other endocrine glands in the body.
Name two hormones and their effect on the body
- Thyroxine: can affect both cells in the heart and also effects cells throughout the body through increasing basal metabolic rate - affecting growth.
- Adrenaline: released from adrenal glands, triggers the fight or flight response.
What happens when someone is scared?
- The hypothalamus activates the pituitary gland.
- The pituitary gland then triggers activity in the SYMPATHETIC branch of the autonomic nervous system.
- From this, the ANS changes from its normal resting state (the PARASYMPATHETIC nervous system) to the physiologically aroused SYMPATHETIC state.
Outline the fight or flight response.
1) The stress hormone adrenaline is released from the adrenal medulla - this triggers physiological changes such as increased heart and breathing rate and pupil dilation.
This release of adrenaline brings about the physiological arousal necessary for the fight or flight response.
2) This happens INSTANTLY when the threat is detected.
It is an acute response and autonomic in the body: bringing about physiological change
3) Once the threat has passed, the parasympathetic nervous system returns the body to it’s resting state. The parasympathetic branch of the ANS works in opposition to the sympathetic nervous system, being called ANTAGONISTIC.
It works as a ‘brake’ to reduce the activities of the body that were enhanced by the actions of the sympathetic branch.
Called: ‘rest and digest’.
Briefly evaluate the nervous and endocrine system (basically fight or flight)
- Simplification of ‘fight or flight’
The reaction is not limited to ‘fight or flight’, some psychologists argue that humans engage in an initial freeze response. A psychologist suggested the first response to danger is to avoid confrontation all together, demonstrated by ‘freeze’. During the freeze, animals and humans are hypervigilant while they analyze the next course of action. - Androcentric theory
Research into the fight or flight response was typically conducted on males, meaning the findings were generalized to females.
Recent research suggests females can resort to a ‘tend and befriend’ response. Taylor et al. believes that they will protect their offspring (tend) and form alliances (befriend) rather than fight an adversary or flee.
This means there is a beta bias within this area of research. - Lack of modern use.
For our ancestors, fight or flight acted as a useful survival mechanism to respond to predators. It can be argued that modern life rarely requires such an intense biological response. From this, the stressors of modern day life can activate the fight or flight response, having negative consequences on health such as blood pressure increase. This means that the FF response in maladaptive in the modern day.
What is a neuron?
A nerve cell that processes and transmits messages through electrical and chemical signals.
What does a sensory neuron do AND what is it’s structure?
- Carries messages from the PNS to the CNS.
- Structure: Long dendrites and short axons.
What does a relay neuron do AND what is it’s structure?
- Connect the sensory neurons to the motor or other relay neurons.
- Structure: Short dendrites and short axons.
What does a motor neuron do AND what is it’s structure?
- Connect the CNS to effectors such as muscles and glands.
- Structure: Short dendrites and long axons.
Write the structure of a neuron.
- All neurons have a cell body (soma) which includes the nucleus - containing the genetic information.
- Branch like structures called dendrites protrude from the cell body - these carry electrical impulses from neighboring neurons TOWARD the cell body.
- The axon carries the impulses away from the cell body down the length of the neuron.
- The axon is covered by a fatty myelin sheath layer that protects and insulates the axon whilst speeding up electrical transmission of the impulse.
- Nodes of Ranvier is where the myelin sheath is segmented (there are gaps) so transmission can be sped up by forcing it to ‘jump’ across gaps along the axon.
- At the end of the axon are TERMINAL BUTTONS that communicate with the next neuron in the chain across the synapse gap.
What is the difference between axons and dendrites?
Axons take signals TO the synapse, dendrites take signals AWAY from the synapse (to the cell body)
How does action potential occur?
Neurons, in resting state, are negatively charged compared to their outside.
When a neuron is activated by a stimulus, the inside of the cell becomes POSITIVELY charged temporarily - causing an ACTION POTENTIAL to occur.
This creates an electrical impulse that travels down the axon towards the end of the neuron.
How do neurons communicate with each other?
They communicate within groups called neural networks.
What does the synapse consist of?
Both the space between two neurons (the synaptic cleft) as well as the presynaptic terminal and post synaptic receptor sites.
What is the difference between signal transmittance WITHIN the neuron vs BETWEEN neurons?
Signals WITHIN the neuron are transmitted electrically.
Signals BETWEEN neurons are transmitted chemically by SYNAPTIC TRANSMISSION.
What happens when an electrical impulse reaches the end of a neuron?
It triggers the release of neurotransmitters from tiny sacs called synaptic vesicles.
Outline the process of synaptic transmission.
1) When an electrical signal reaches the presynaptic terminal (end of the neuron) it causes the release of synaptic vesicles which carry neurotransmitters.
2) Once the neurotransmitters within the synaptic vesicles cross the synapse they bind to post-synaptic receptor sites on the dendrites of the next neuron. These receptors (of course) are complimentary in shape to the neurotransmitters.
3) The neurotransmitter is converted back into an electrical message to transmit through the post-synaptic neuron. The process then repeats.
4) Excitation and inhibition effect
5) SUMMATION - very important !!!
What is excitation and inhibition?
- Excitation increases the positive charge of the post-synaptic neuron, INCREASING the likelihood of the neuron firing and passing on an electrical impulse (e.g adrenaline)
- Inhibition increases the negative charge of the post-synaptic neuron, DECREASING the likelihood of a neuron firing and passing on an electrical impulse (e.g- serotonin)
What is summation and what does it do and outline the process.
Summation decides whether the a post-synaptic neuron fires.
In summation, the excitatory and inhibitory effects are ‘summed’
If the overall effect in inhibitory, the neuron is less likely to fire
If the overall effect is excitatory, the neuron is more likely to fire.
Therefore, the action potential of the post-synaptic neuron is only triggered if the sum of the excitatory and inhibitory signals reach a certain threshold.
! For a neuron to fire or not, a certain excitatory or inhibitory effect threshold must be met.
What is localization of function theory?
The theory that different areas of the brain are responsible for different behaviors, processes or activities.
Who pioneered localization theory?
Paul Broca and Karl Wernicke.
What is the opposite of localization of function theory?
Holistic theory - the idea that ALL parts of the brain were involved in the processing of thought and action.
What is another word for localization theory?
Cortical specialization.
What is lateralization?
Where some of our physical and psychological functions are controlled or dominated by a particular hemisphere (either right or left hemisphere)
True or false: Activity on the left-hand side of the body is controlled by the right hemisphere and vice-versa.
TRUE!
This is called cross-wiring.
Name the 4 lobes in the brain.
- The frontal lobe
- The parietal lobe
- The occipital lobe
- The temporal lobe
Where is the motor area located?
The back of the frontal lobe (in BOTH hemispheres).
What is the motor areas function and what would damage to the area do?
- Function: Controls voluntary movement on opposite sides of the body.
- Damage: Loss of control over fine movement regulation.
Where is the somatosensory area located?
At the front of both parietal lobes
(Separated from the motor area by the central sulcus valley)
What is the somatosensory areas function and what would damage to the area do?
- Function: Where sensory information from the skin is represented.
(The amount of the somatosensory area devoted to a particular body part denotes it’s sensitivity: the hand and face receptors occupy over half of this area) - Damage: Sensitivity.
Where is the visual area?
In the occipital lobe at the back of the brain.
What is the visual areas function and what would damage to the area do?
- Function: Each eye sends information from the right visual field to the left visual CORTEX, and information from the left visual field to the right visual CORTEX.
- Damage: For example, damage to the left hemisphere can produce blindness in the part of the right visual field in both eyes and vice-versa.
Where is the auditory area?
In the temporal lobes (on the side of the brain)
What is the auditory areas function and what would damage to the area do?
- Function: Analyses speech based information.
- Damage: Partial hearing loss.
What areas are the language centers of the brain?
- Wernicke’s area
- Broca’s area
Where is the Broca’s area?
In the LEFT frontal lobe
What is Broca’s area responsible for and what does damage to the area cause?
- Responsible for speech production.
- Damage to the area causes Broca’s aphasia - this is characterized by slow, labored speech that is lacking in fluency.
(For example, Broca’s patient Tan could only say the word ‘Tan’ - In addition, they struggle with predispositions and conjunctives)
Where is Wernicke’s area?
In the LEFT temporal lobe.
What is Wernicke’s area responsible for and what does damage to the area cause?
- Responsible for language comprehension / understanding.
- Damage to the area causes Wernicke’s aphasia - characterized by having no problems producing language but severe difficulty understanding it: they produce nonsense words (NEOLOGISMS)
What is the difference between Broca’s aphasia and Wernicke’s aphasia?
- In Broca’s aphasia, the patients have no issue comprehending language but struggle to produce language.
- In Wernicke’s aphasia, the patients are able to produce language, yet lack language comprehension.
Evaluate Localization of function in the brain.
- Evidence from neurosurgery
Damage to brain areas have been linked to mental disorders. Neurosurgery for mental illness exists as a last resort treatment, with a cingulotomy being a common surgery. A cingulotomy involves isolating a region called the cingulate gyrus which is implicated in OCD. Dougherty et al. followed up 44 people with this disorder who had the operation. After 32 weeks, 30% had met the criteria for a successful response to surgery. The relative success of these procedures suggest that behaviors associated with disorders may be localized to sections of the brain. - Evidence from brain scans
Brain scans support localization theory. Petersen (like in memory topic!) had used scans to demonstrate how Broca’s area was active during reading tasks and Wernicke’s area was active during listening tasks.
In addition, Petersen also contributed to scan studies showing how episodic and semantic memory reside in different areas of the prefrontal cortex. This means objective methods for measuring brain activity have provided evidence that many brain functions are localized. - Counter-evidence.
Karl Lashley had removed 10-50% of rats cortexes who were learning to navigate a maze. In this, no area was proven to be more important than the other in terms of the rats ability to find a route through the maze. The learning process appeared to require every part of the cortex rather than one specific area. This suggests that higher cognitive processes, such as learning, are not localized but distributed more holistically. - Case study criticism (GAGE)
Case studies of neurological damage support localization theory but only to a certain extent. There are limitations in terms of how it is difficult to make meaningful generalizations on findings from single individuals and it is inappropriate to make inferences on what they were like before damage.
