Biological Psychology Flashcards
Describe the different ways to administer drugs
All aim to affect the CNS
- Oral Ingestion - Easy and safe method, but unpredictable. Can damage digestive system
- Injection - Strong, fast and predictable effects. Higher infection risk and hard to reduce the effects of.
- Inhalation - Absorbed into the bloodstream through capillaries in lungs. Difficult to regulate, can damage lungs.
- Absorption through mucous membranes - Nose, mouth, rectum.
How do drugs penetrate the CNS?
Blood brain barrier makes it difficult for dangerous chemicals to pass from blood vessels of CNS into neurons.
Affect the nervous system differently. Bind to synaptic receptors by influencing neurotransmitters or influence chain of chemical reactions elicited in postsynaptic neurons by activation of their receptors.
Drug metabolism mediated by liver enzymes. Eliminates drugs ability to pass through lipid membranes so can no longer penetrate blood-brain barrier.
What is drug tolerance?
State of decreased sensitivity to a drug that develops as a result of exposure to it
Two categories
- Metabolic intolerance - tolerance due to changes reducing the amount of drug getting to action site
- Functional tolerance - Tolerance due to changes that reduce the reactivity of action sites.
What is drug withdrawal?
Adverse effects of discontinuing drug use. Opposite effects to drug. Suggests that effects may be produced by same neural changes that produce drug tolerance. Exposure changes the nervous system, when no longer present, neural changes create a symptom.
Is there a genetic component to drug addiction?
Has a higher genetic predisposition than some diseases.
Sons of alcohol dependent fathers have increased alcohol tolerance and reduced hangovers.
Enzyme aldehyde dehydrogenase involved in metabolism of alcohol. Those deficient experience skin flushing when alcohol is less effectively metabolised.
Pinel, Mana & Kim (1989)
- Looking at contingent tolerance to the anticonvulsant effect of alcohol.
- Rats that received alcohol before convulsive stimulation became tolerance to its anticonvulsant effect
- Rats that received the same injections after a convulsive stimulation did not become tolerant.
Crowell, Hinson & Siegel (1981)
- 2 groups of rats receiving 20 alcohol and 20 saline injections
- One group received all 20 alcohol injections in a distinctive test room and the 20 saline injections in their colony room, while other group of rats received alcohol in colony room and saline in distinctive.
- Assessed the hypothermic - temperature-reducing effects of alcohol.
- Only found tolerance in rats who were injected in the environment that had been paired with alcohol administration. Tolerance has a phycological component. The body predicts it, so makes adjustments.
- Drug addicts may overdose when receive drug in new context. Tolerance in same environment.
Siegel et al. (1982)
More heroin tolerant rats died from a large dose in a novel environment compared in familiar.
Shows that drug administration in novel contexts can be deadly.
Describe the physical dependence approach to drug addiction
Stats that addicts are trapped in a circle of drug taking and withdrawal syndromes.
Early treatment programs were based on this. Tried to break the cycle. Failed bc some drugs do not produce withdrawal distress and drug taking patterns differ.
Led to positive incentive theories of addiction - addicts take drugs to obtain the pleasure of the drug.
Describe intracranial self-stimulation
Self-administered shock to pleasure centers of the brain
Olds and Milner (1954) discovered this, stating that brain sites that mediate self-stimulation are those that normally mediate the pleasurable effects of natural rewards.
The mesocortical pathway plays an important role for reward processing and drug self-administration.
Evidence is that
- Lesions to path disrupt self-stimulation
- Hernandez et al. (2006) - Self-stimulation led to increased DA in pathway.
Mesocortical Pathway
Path through which dopaminergic projections travel to reach the neocortex.
Important for reward processing and drug self-administration
Nigrostriatal pathway
The dopaminergic tract from the substantia nigra to the striatum.
Associated with motor control.
Degeneration associated with parkinsons.
Dopamine and drug addiction
DA antagonists are drugs which interfere or inhbibt the physiological action of DA. They mainly abloish self-administration and conditioned place preference effects.
Dopamine is important in the rewarding effects of drugs.
Nucleus accumbens and drug addiction
Part of the mescocortical DA pathway which receives inputs from the ventral tegmental area. Seems to be related to reward and pleasure.
Findings
- Animals self-administered drugs into area
- Injections produced a conditioned place preference for compartment of administration
- Lesions blocked self-administration and development of place preferences.
- Self-administration shows increased levels of extracellular dopamine in area.
Habitual Drug Use
Positive incentive theory says ppl motivated to take drugs by the anticipated pleasure. There is a decreased hedonic value (liking) of drug.
Mesotelencephalic DA system plays a role in drug anticipation as neutral stimuli that predict drug administration predict increased firing of DA activity in rats (Weiss et al., 2000).
Childress et al. (1999) - Cues associated with drug use led to increased activation in drug-associated brain regions.
Explain the reasons for drug relapse
- Stress
- Drug-priming - exposure to formerly abused drug.
- Exposure to cues associated with drug taking e.g. US soldiers addicted to heroin in Vietnam war got rid of addiction once returned home.
Pickens et al. (2011) - After cocaine withdrawal there was a gradual increase in lever pressing for cocaine in response to cue. Explains why people relapse after years of absence. Suggested that improving the surroundings of drug addicts is useful.
What is comparative cognition?
Comparative cognition is the aim of understanding cognition across the animal kingdom, looking at how it works, what is good nature and how it evolved (Shettleworth, 2010).
Important to investigate both humans and other species. Comparisons can help us be informed of the origins of our own cognition.
Best way to do this is to look at functional similarities. When investigating a non-verbal species, need to accept a part of the animals behaviour as the same as a persons verbal account. Means you never know if it is correct or not.
Wittlinger, Wehner, & Wolf (2006) Ants
Saharan desert ants are able to return home in a straight line. Suggested that they measure distance between stops and know distance home.
Manipulated ant’s legs. Shortened, normal, stilts.
Stump and stilt = overshot
Normal = Found way home.
Suggested that they have some form of pedometer, counting their steps to guide them home. Have specialised navigation skills.
Describe the importance of the cortex in investigating brain size
Humans have a large pre-frontal cortex compared to other species.
Dunbar (2009) - investigated relationship between size of social group and neocortex ratio. Found that social group size is the best predictor of neocortex size. In humans, it is suggested that pre-frontal cortex necessary for formation of complex social groups. Evidence against the foraging hypothesis. Sociality is the main selection pressure on primate brain size.
Barton (2006) - Primates have large neocortex, but no known cognitive processes mediated mainly by it. Instead, they are mediated by networks that link neocortex with other structures. Suggesting that it process info from all senses. Primate have complex visual systems, reason for large brains in humans as visual specilisaion important and a central part of human evolution.
Some studies also suggest visual specialisation linked to sociality, links with Dunbar.
Explain the role of the Hippocampus on brain size within comparative cognition
Foraging hypothesis - Proposed that there are correlations between brain size and foraging behaviour. This was an early idea which lead to the idea that large brains reflect selection on cognitive abilities.
Jerison (1973) - Principle of proper mass, the more important a function is, the more brain area is devoted to it.
E.g. of elephants - Hippocampus where mental maps stored. Elephants have large hippocampus, behaviour of walking long distances to watering holes.
Garamszegi and Eens (2004) - birds who store a lot of food usually have larger brains than expected for brain size, perhaps reflecting sensory and motor specialisations in storing and retrieving food behaviour. Idea of mental maps.
Healy and Clayton (1994) - brains of food storing birds. Brain develops quickly within the first few weeks of life. Marsh tits who are food stores, show a continual increase in the hippocampus which is also influenced by experience in using spatial memory.
What are the limitations in looking at intelligence within comparative cognition?
Shettleworth (2010) - Claims that it is not a useful term for describing animal behaviour. It describes a global ability in humans, whereas cognitive abilities of animals mainly modular.
Needs to be defined formally in respect to a specific goal. Biological intelligence should be defined in terms of fitness or goals e.g. choosing a good mate.
Vickery & Neuringer (2000) - Different intelligences are employed in different situations by different species.
What is evidence for behavioural evolution within comparative cognition?
Tinbergen et al. (1963) - Eggshell removal in gulls. Bird leaves chicks to drop off egg shells. Removing them protects offspring by predators.
Looked at other gull species unaccessible to predators - they did not remove eggs from nest.
Fullard et al. (2004) - Bat avoidance behaviour in moths. Bats search for moths by using ultrasonic cries. On island of Tahiti, Bats not present yet auditory nerves of moths still fire to bat cries, but did not drop to the ground. In the absence of selection, the sensory input has been decoupled from the motor avoidance response.
This is an example of natural selection shaping cognition.
Describe the process of mate bonding within comparative cogniton
Evolutionary psychologists understand human behaviour through considering the pressures that led to their evolution.
Most mammals form mating bonds.
Polyandry - Matting arrangement where 1 female bonds with more than 1 male. Only in species where reproductive contributions of males are greater than those of females. Males need better ability to process and remember spatial info than females.
Monogamy - Bonds formed between 1 male and female. In species where each female could raise more young if had more help. Need similar abilities to find way around.
When comparing species differences in cognition, it must be based on more than 1 test.
Describe neuronal density within comparative cogniton
Herculano-Houzel (2009, 2011) - Neuronal density scales are different across mammals. Number of neurons is correlated in cerebral cortex & cerebellum. Coordinated scaling. In primates, cerebral cortex increases in mass as gains neurons to a greater degree than the cerebellum therefore its relative mass increases
Cognition depends on an absolute feature of the brain e.g. total number of corticial neurons and conduction velocity of fibres.
What are the limitations in comparing brain sizes across species?
Much research has questioned why some have larger brains relative to body weight.
The foraging hypothesis explores the connection between brain and cognitive abilities. Says that fruit eating species need good spatial and temporal learning abilities for tracking scattered locations.
Led to the question of exploring how parts of the brain evolve in association with specific behaviours. Whether it is concerted or mosaic.
Same brain parts in many veretebrates, but sizes are structures characteristics of each group.
What are the two divisions of the peripheral nervous system?
Division outside the skull and spine.
Somatic Nervous System
Interacts with external environment. Composed of afferent nerves which carry sensory signals to the CNS and efferent nerves which carry motor signals from the CNS to muscles.
Autonomic NS
Regulates the body’s internal environment. Afferent nerves carry signals from the internal organs to the CNS. Efferent nerves carry motor signals from the CNS to internal organs.
Has 2 kinds of efferent nerves - sympathetic - autonomic motor nerves that project from the CNS and spinal cord. Parasympathetic nerves project from brain and part of spinal cord.
Which division of the brain is this?
Hindbrain
Describe the cerebrum
Controls abstract thought and learning.
Central and lateral fissure divide each hemisphere into 4 lobes - frontal, parietal, temporal, occipital.
Which area of the cortex is this?
Frontal lobe
Motor activity, speech, planning, impulse control
Which area of the cortex is this?
Parietal Lobe
Integrates sensory information by sensing body position and integrating visual information.
Spatial tasks.
Which area of the cortex is this?
Temporal lobe.
Contains the primary auditory cortex involved in processing auditory information. Left temporal lobe contains Wernicke’s area - involved in language comprehension.
Which area of the cortex is this?
Occipital lobe
Contains the primary visual cortex which handles visual information.
What are the different classes of neuron?
Multipolar: 2+ processes extending from cell body
Unipolar: 1 process extending
Bipolar: 2 processes extending
Interneurons: Neurons with a short/no axon. Integrate the neural activity within a single brain structure.
What do glial cells do and what kinds are there?
- Surround neurons and provide support and insulation.
- Exchange chemical signals with neurons to control establishment and maintenance of synpases between neurons
- Moderate neural activity
- Control blood-brain barrier
Oligodendrocytes - Extensions, help information move faster along axons.
Schwann Cells - Form spirals around axon. Guide axonal regrowth after damage.
Astrocytes - Star-shaped. Allow passage of chemicals from blood to CNS. Regulate blood flow to brain. Form the blood brain barrier.
Microglia: Respond to injury and disease by triggering inflamatory reponses.
Describe how the spinal cord is made up?
Two different areas
- Gray matter: Cell bodies and unmyelinated interneurons
- White mattter: Myelinated axons
Axons join via the dorsal root or ventral root.
Dorsal root axons form the dorsal root ganglia.
Evaluate the use of MRI
- High res images
- High spatial resolution
- 3D images
Evaluate the use of fMRI
- Images of oxygen flow in the blood to active areas of brain. Active areas use more oxygenated blood. Oxygenated blood has magnetic properties that influenced the waves.
- Poor temporal resolution
- Nothing injected
- Better spatial resolution
Introduction to memory
Memory - process of storing and retrieving information.Important process to human life.
The importance of memory means that damage to the brain can have a detrimental effect, producing memory disorders. Study of memory disorders has contributed to understanding of memory.
One of the most influential models of memory is the multi-store model proposed by Atkinson & Shiffrin (1968).
3 stores are proposed,
- sensory stores
- short-term stores
- long-term store.
The model proposes that information is lost because it decays and that long-term memories are lost through the process of retrieval.
Describe the case of HM
Epileptic who had temporal lobes removed which reduced LTM. Suffered from mild retrograde amnesia - inability to remember the past. Could still recall from childhood, why it is mild. Also, severe anterograde amnesia - no longer form new memories. Most STM intact.
Tests of measurment
- Block-tapping memory test - STM good for spatial info
- Digit-span test - Recall digits provided the time between learning and recall was within the duriation of STM.
- Incomplete Pictures & Mirror Tracing - Ev of new memory. He improved performance over time, but could not refer back to the first time when he performed the task.
Findings
- Led to distinction between STM and LTM. Separate.
- He had problems with memory consolidation. Could not move memories from STM to LTM.
- 2 categories of LTM, explicit and implicit memory.
- Shown that medial temporal lobe important within memory. Challenging view at the time that memory functions were diffused throughout the brain.
What is the difference between retrograde and anterograde amnesia?
Retrograde: Inability to recall past memories
Anterograde: Inability to create new memories
Describe the case of Clive Wearing
Herpes simplex encephalistis, inflammation in left temporal lobe, severe damage to hippocampus. Extremely short memory span.
- Able to remember he was married = spared semantic memory
- Could not remember wedding = impaired episodic memory
- Could not remember divorce = Impaired semantic memory
- Asked if remembered PM John Major, but earlier on seen car with plate ‘JMV’ and instantly said ‘John Major vehicle’ showing he had implicit memory for his name.
Describe the case of K.C.
Damage to brain, both hippocampi. Suffered from anterograde amnesia and gradual retrograde amnesia. Could not store new memories and recall past just before accident, but could recall far back memories. Intact semantic memory, but lacked episodic memory of past.
It was suggested that hippocampus important for episodic memory, however damage left semantic intact, leading to the suggestion that episodic and semantic memory could be formed and stored separtely, processed by different brain regions.
Visual imagery, emotion centres in the brain and fontal areas invovled in self-referential processing important for autobiographical memories.
Describe the case of Jon and his memory problems
Examined by Baddeley, Vargha-Khadem and Mishikin (2001).
Had developmental amnesia due to premature birth and anoxia, resulted in severe hippocampal damage. From age of 5, memory problems apparent. However, had good intelligence and semantic memory, impaired recall, but intact recognition. Led to suggestion that episodic memory not necessary for recognition or acquisition of semantic knowledge.
Describe the case of Patient R.B. (Memory)
Suffered damage to one part of hippocampus (CA1 pyramidal cell layer) and developed amnesia. Suggests that hippocampal damage alone can produce amnesia.
Transient global amnesia the strongest evidence that selective hippocampal damage can cauase medial temporal lobe amnesia. Shorter, lasts 4-6 hours, happens suddenly in normal adults.
This also related to abnormalities in the CA1 subfield of the hippocampus.
What is memory consolidation and is there any evidence for it happening?
Common form of amnesia is post-traumatic amnesia - usually due to concussion. May cause retrograde amnesia for time before injury and anterograde for time after.
Period of anterograde amnesia suggests a temporary failure of memory consolidation. Concussions disrupt recent memories, suggesting that older ones have been stregthened = evidence of memory consolidation.
Describe Hebb’s (1949) theory of memory consolidation
Argued that memories of experiences are stored in the short-term by neural activity. These memories at risk of disription, but eventually structural changes in synapses provide them with stable long-term storage. Suggests that it is a brief process.
Usually studied by using electroconvulsive shock (ECS) - intense, seizure-inducing current to the brain through electrodes on scalp.
Squire, Slater and Chace (1975) in response to Hebb (1949)
Found a long-gradient of ECS-produced retrograde amensia when measuring memory for TV shows prior to ECS therapy.
Found that lasting memories become more reistant to disruption throughout life. It is not a brief process like Hebb suggests.
