PSYC317- biopsychology

Biopsychology

The merging discipline of biology and psychology. Reciprocal relationship between the nervous system and behavior/cognition. behaviour and mental processes.

bidirectional relationship between nervous system and behaviour

certain neural activity patterns can generate certain behaviours/cognitions, certain behaviours, cognitions and experiences can alter certain neural activity patterns

neuroplasticity

ability of the nervous system to change and remodel

the brains ability to change an adapt in response to experience, learning, and environmental factors. Adaptability results in formation of new neural connections, and the strengthening or weakening of existing connections

ancient Egyptians & Greeks views on the brain

• ancient Egyptian did not consider brain to be central organ driving behaviour, seen in mummification practices

• Greeks thought capabilities stemmed from the heart

what would a materialist believe?

thoughts have a physical basis and stem from patterns of neural activity in the brain. Materialism is the philosophical view that everything that exists is physical, and that mental processes are the result of physical interactions within the brain. Everything is by function of the brain.

what did Claudia’s Galenus notice about the brain?

people with head injuries behave differently and muscle movement was linked to nerves.

Rene Descartes

did not understand how the physical aspects of the brain could give rise to the non-physical (thought) came up with the idea of duality distinguishing the mind and the body.

what did Thomas Willis suggest about the brain?

was the first person to say the brain generates behaviour

what did Julien de la Mettrie suggest about the brain?

that thoughts are produced by the brain, humans and animals are equally complex

what did Darwin, Broca, Ramon y Cajal do?

in the 19th century they looked at the biology of the brain

what did Wundt. Weber, Fechner and James do?

developed psychology

what did Luria, Lashley, Hebb, & Sperry do?

in the mid 20th century looked at both the biology and psychology

modern perspective of biopsychology

outward behaviors and cognitive processes are generated by neural activity, if neural activity is altered behaviours and cognitive processes may be altered.

what are the major shifts in thinking that have occurred in the development of biopsychology?

brain influences behaviour, behaviours have a material/physical basis, manipulations including environment can alter brain structure and function, we can modify brain activity and cognition/behaviour

what are three ways to alter behaviour via neural activity?

disease, tissue damage/removal, stimulation, drugs, development & learning

according to John Watson what is the most important determinant of human behaviour?

the environment

what is nurture?

behaviours stem from individual learning/experience, behaviourism-driven, behaviours can be shaped and conditioned in a laboratory, idea that everything is learned and behaviour can be shaped, eg 1930s John Watson and other behaviourists

what is an example of nurture?

Watson & Rayner 1920 little Albert experience, his fear was acquired.

what is nature?

idea that behaviours stem from inherited factors/genes, ethology driven, instinctive behaviours seemingly present in all members of a species, some behaviours are genetically predetermined, eg 1859 Charles Darwin's origin of species

interactions of nature and nurture

behaviours result from an interaction of genes and experience, i.e. DNA and organ systems that develop from DNA interact with environment starting in utero, includes nutrition, sensory stimulation, stress exposure, social interaction, education, past decisions etc

what is the situation?

immediate circumstances and environment in which the person finds themselve

interactions of nature, nurture and situation

behaviours result from interactions of genes, experiences, and the current situation you find yourself in.

What did Tyron et al.’s experiments with rats show with regards to heredity and learning (nature)?

• tested rats in mazes, he selectively bred maze bright rats with each other and maze dull rats with each other. Over successive generations, the offspring of the maze-bright consistently performed better in the maze tasks than the offspring of the maze-dull rats. 

• genetic predisposition for good and bad learning abilities in the maze. Assumed a potential for a genetic factor controlling their ability to learn (nature).

• confounds- potential environmental influences

Searle (1949) looking at fear not intelligence

Compared selectively bred maze-dull and bright rats on different behavioural tests. Concluded that dull rats weren’t dull, they were scared of mazes

Cooper & Zubek 1958

Placed rats in an enriched environment, there is no change in performance of bright rats, but there is a change in performance for maze dull rats with an increase in performance. There is an environmental effect NOT just genes.

Little Albert experiment by Watson & Rayner

9 month old Albert with no fear to a variety of objects was exposed to pairings of loud sounds and visual stimuli (rat) making in uncomfortable. continuous pairings of stimuli together result in Albert displaying a generalised fear to all stimuli. behaviour can be learnt.

define epigenetics

the study of changes in gene expression that do not involve alterations to the underlying DNA sequence.

how is DNA read?

when epigenetics factors binds to histone tail it causes it to unwound allowing gene to be read.

what is the function of the methyl group?

when added to DNA it can block access to DNA, blocking expression of a gene.

what are two epigenetic mechanisms?

histone modification & DNA methylation allowing access to DNA or not.

what has resulted in evolution?

brain mass increased, bipedalism allowing for ability to use hands and manipulate tools.

what did the Triune Brain Model describe?

three key brain regions consisting of:

1. Reptilian brain

2. Paleomammalian brain (limbic system)

3. Neo mammalian brain

flaws of the triune model?

• too simplistic, suggests reptilians do not have a cortex, yet they do.

• suggested three brain regions evolved separately and function independently but they work together.

• limbic system and neocortex work together interconnected, limbic not solely emotion, with neocortex cognition/higher order functioning

what are the two main divisions of the nervous system?

central nervous system & peripheral nervous system

what does the central nervous system consist of?

the brain and spinal cord

the peripheral nervous system can further be divided into?

somatic nervous system and autonomic nervous system (parasympathetic, sympathetic)

afferent nerves includes?

the arrival and input

efferent nerves

exiting and output

sympathetic nervous system has what function?

fight or flight mode

parasympathetic nervous system has what function?

used for resting and digesting

what are cells?

the basic units of the nervous system are neurons and glial cells. Neurons are responsible for transmitting signals, while glial cells support and protect neurons.

what is the tissue?

nervous tissue is composed of densely packed neurons and glial cells. Forms brain, spinal cord, and nerves.

Neuron are?

electrically excitable cells. A nerve cell responsible for transmitting electrochemical signals to other cells via neurotransmitters. generates action potentials.

glia

support cells for neurons

astrocytes

involved in information processing, releasing neurotransmitters, bidirectional communication between neurons and astrocytes. involved in plasticity and trophic support for neurons.

oligodendrocytes and schwann cells

myelination of axons

microglia

involved in inflammatory response

nucleus/ganglion

cluster of cell bodies

axon tract/nerve

bundle of axons

glutamate

main excitatory neurotransmitter

GABA

main inhibitory neurotransmitter

vesicles

full of neurotransmitters. action potential causes vesicles to fuse with the membrane and release neurotransmitter.

synapses

allows signal to pass from one neuron to the next, synaptic transmission. key sites for altering neural activity patterns which can alter behaviours. e.g., Alzheimer's memory deficits involves weakening and loss of synapses

spinal cord

motorway that allows bidirectional communication between the brain and rest of the body. critical for enabling brain to receive and send information to muscles, skin, gut, vasculature, heart etc.

• damage to spinal cord can cause loss afferent or efferent information from a certain region of the body

CNS

Central Nervous System, comprising the brain and spinal cord, critical for processing sensory information and executing responses.

PNS

Peripheral Nervous System, including somatic/motor and autonomic systems, responsible for transmitting information to and from the CNS.

autonomic nervous system

nerves regulating the activity of internal state

anterior (rostral)

front

posterior (caudal)

back

superior (dorsal)

top

inferior (ventral)

bottom

medial

towards midline

lateral

away from midline

frontal lobe

involved in decision making, problem-solving, and planning 

parietal lobe

processes sensory information e.g., (touch, temperature, pain) 

temporal lobe

involved in memory, emotion, and auditory processing 

occipital lobe

responsible for visual processing 

cortex

the outer layer of the brain, involved in higher brain functions such a thought and action. important for complex cognition.

thalamus

'relay station' all sensory information (except smell) proceeds to the cortex and stops in the thalamus before being sent off. Sensory and motor signals. 

hypothalamus

below the thalamus, regulates vital bodily functions e.g., hunger, thirst, temperature.

brain stem

connects the brain to the spinal cord and controls basic life functions such as breathing, heart rate, and blood pressure. (midbrain, pons, medulla)

cerebellum

back of the brain, involved in co-ordination and balance, sensorimotor.

spinal cord

main pathway for information connecting the brain and PNS 

striatum

part of basal ganglia, involved in movement and reward processing 

reticular formation

runs through the middle of the brainstem, important in sleep

pons and medulla

axon tracts. have clusters of cells dotted around the brainstem.

Neuronal Communication

Transmission of signals from neurons to various targets like other neurons, muscles, or glands.

Brainstem

Part of the brain critical for sleep regulation and basic physiological functions.

Hippocampus

Brain structure involved in memory formation and spatial navigation. in temporal lobe

Microglia

Glial cells involved in the inflammatory response in the central nervous system.

limbic system

key regulator of basic motivated behaviours, memory, emotion, many structures mainly in temporal lobe

basal ganglia system

key for voluntary motor activity, reward based learning, novelty, eg dopamine as a reward signal for learning

what does the brain require to work?

energy (glucose), needs a good blood supply

what protects and nourished the brain?

skull and meninges, CSF

what do you not want to get on the brain tissue

blood as it is toxic

what are the meninges?

• dura mater

• arachnoid mater

• pia mater

what is the purpose of the meninges?

they are protective membranes the protect brain and spinal cord providing structure, support, protection and nourishment to CNS.

what is CSF?

cerebospinal fluid

how does CSF benefit the brain?

• shock absorption, buoyancy, nutrient delivery and waste removal, homeostasis, immune functions, structural support. 

• Vital for health and functioning of the brain and CNS. Protective, supportive, metabolic roles ensure the brain remains safe from injury, received necessary nutrients, and maintains stable internal environment.

what produces CSF and where?

choroid plexus in the lateral ventricles, exit the fourth ventricle

what is the blood brain barrier (BBB) and how does it benefit the brain?

barrier composed of endothelial cells. Aim to protect brain from toxic substances, filter harmful compounds from the brain to bloodstream and supply brain tissue with nutrients. 

how does the brain get oxygen and nutrients?

vasculature, blood brain barrier controls entry/exit of molecules into the brain.

what breaks down glucose in the brain

astrocytes

what is hydrocephalus?

is the abnormal build up of CFS in the ventricles within the brain

dissection pros and cons

(+) able to find some diagnosis (alzheimers) post mortem diagnosis can be confirmed by looking at pattern of atrophy.

(-) can't see it in action, just anatomy not function, organism no longer alive

(-) not ethical unless consensual

what are the types of gross anatomy via imaging?

CT- computerised tomography scan

MRI- magnetic resonance imaging

DTI- diffusion tensor imaging (fibre tracts)

what are the pros and cons of gross anatomy via imaging?

(+) can scan a living brain

(+) can localise damage if someone has had a stroke (CT)

(-) not getting the function of the brain only anatomical detail

what is histology?

the study of tissue

looking at anatomy via histology

shown on a microscopic level

• shows basic visualisation’s of cells

e.g.,

• nissl stains - stain cell bodies, good for counting number of cells, whether a disease state is associated with loss in a particular region ie Alzheimer's, can do a cell count, good way of showing cell loss.

• golgi stains = can look at individual dendrites, high resolution and fine detail, may tell you how a disease state is affecting the structure/function of a cell

(-) no function, indirect correlative measure, not watching cell activity just a secondary measure

another kind of microscopic anatomy via histology

• immunohistochemistry and in situ hybridisation to visualise certain cells via antibody. use antibodies to check for certain antigens in a sample of tissue particular protein or gene of interest.

• starting to visualise certain connections e.g. antero/retrograde tracing.

(-) no function