24th October 2023

Information Processing

Attention

Attention is a complex process which involves areas that we have discussed previously: memory and perception. It is a term which is difficult to define despite being used in everyday language (Styles, 2006). Attention is associated with our selective processing of the information received through our senses, which thereby has a large impact on our understanding of the world (Driver, 2010). You may be tempted to use ‘attention’ synonymously with ‘focus’; however, to visually focus on an object does not necessarily prevent you from seeing objects around it. Similarly, focusing on an object does not guarantee that your attention will not be drawn elsewhere (Styles, 2006).

One way of appreciating attention is to divide it into three components: alertness, selectivity and processing capacity (Posner and Boies, 1971). Relating this back to memory, alertness is similar to the processing of sensory information, whilst selectivity moves this into short-term memory. We can relate this back to the working memory model, as each compartment only has a limited capacity to receive new information at any one time. Similarly, in the case of H.M., memory was reliant on maintaining attention on a piece of information.

Clinical relevance of information processing

Schizophrenia

Psychotic experiences could be described as altered information processing, with one of the core features being hallucinations. An example of a process which may underlie this is psychosocial stress leading to dysregulation of dopaminergic signalling, which may interfere with processing biologically-important events (Heinz et al, 2019). schizophrenia is an example of a psychotic illness, which often features auditory hallucinations. One study used PET to appraise which areas of the brain appeared to be more active in people with auditory verbal hallucinations due to schizophrenia. They found that some of the areas affected were similar to the regions we previously described as being important in memory: the hippocampus and limbic structures, the paralimbic regions, and also the thalamus (Silbersweig et al, 1995). This was a small study, but it supports the role of these structures in generating or modulating hallucinations in Schizophrenia patients.

In schizophrenia, there are also thought to be disturbances in attention. Luck and Gold (2008) concluded that some components of attention are compromised in schizophrenia, but other parts are comparatively unhindered. In particular, they identified that control of selection in attention was impaired. This meant that patients with schizophrenia found it more difficult to guide their attention towards inputs that were relevant to a given task. However, the processing of the selected stimuli had little or no impairment (Luck and Gold, 2000). These disturbances in attention were supported by research into biomarkers of attention. One study suggested that there could be progressive deterioration in the automatic processes of sensory discrimination, orienting and reorienting of attention as schizophrenia becomes more chronic (Jahshan et al, 2011).

Attention-deficit / hyperactivity disorder (ADHD)

ADHD is a common neurodevelopmental disorder which has been identified in both children and adults worldwide. ADHD may present in different ways between individuals, but symptoms broadly begin during childhood and may feature inattention, hyperactivity and / or impulsivity (Cortese and Coghill, 2018). The worldwide prevalence is difficult to quantify due to variations in diagnosis between countries. However, it is thought to be around 5% (Cortese and Coghill, 2018).

The cause of ADHD is not definitively known, but it is likely to be a combination of genetic and environmental factors. Genome-wide association studies (GWAS) of over 20,000 ADHD cases identified variants exceeding genome-wide significance in 12 independent loci, supporting an underlying genetic cause for ADHD (Demontis et al, 2017). In addition, some of the environmental risk factors for developing ADHD include maternal smoking and alcohol use during pregnancy, low birth weight, premature birth, and exposure to certain environmental toxins such as oregano (Cortese and Coghill, 2018). Neuroimaging studies have attempted to identify which regions of the brain function differently in people with ADHD. A meta-analysis of 55 fMRI studies showed that adults with ADHD had significant hyperactivation, mainly in the default, ventral attention, and somatomotor networks of the brain. Conversely, in children with ADHD, most of the hypoactivated areas of the brain were related to the ventral attention and the frontoparietal networks (Cortese et al, 2012). Along with the genetic research, this supports the idea that there is at least a partly biological origin for ADHD.

References

• Cortese, S. Coghill, D. (2018). Twenty years of research on attention-deficit/hyperactivity disorder (ADHD): looking back, looking forward. Evidence-based Mental Health. 21(4), pp. 173-176. PMID: 30301823.
• Cortese, S. Kelly, C. Chabernaud, C. Proal, E. Di Martino, A. Milham, M. Castellanos, X. Toward systems neuroscience of ADHD: a meta-analysis of 55 fMRI studies. American Journal of Psychiatry. 169(10), pp. 1038-55. PMID: 22983386.
• Demontis, D. et al (2017). Discovery of the first genome-wide significant risk loci for ADHD. Nature Genetics. 51(1), pp. 63-75. Available at: https://doi.org/10.1038/s41588-018-0269-7.
• Driver, J. (2010). A Selective Review of Selective Attention Research from the Past Century. British Journal of Psychology. 92(Pt 1), pp. 53-78. PMID: 11256770.
• Silbersweig, D. et al. (1995). A functional neuroanatomy of hallucinations in schizophrenia. Nature. 378, pp. 176–179. Available at: https://doi.org/10.1038/378176a0.
• Heinz, A. et al. (2019). Towards a Unifying Cognitive, Neurophysiological, and Computational Neuroscience Account of Schizophrenia. Schizophrenia Bulletin. 45(5), pp. 1092–1100. Available at: https://doi.org/10.1093/schbul/sby154.
• Jahshan, C. et al. (2011). Automatic sensory information processing abnormalities across the illness course of schizophrenia. Psychological Medicine. 42(1), pp. 85-97. Available at: https://doi.org/10.1017/S0033291711001061.
• Luck, S. Gold, J. (2008). The Construct of Attention in Schizophrenia. Biological Psychiatry. 64(1), pp. 34-39. Available at: https://doi.org/10.1016/j.biopsych.2008.02.014.
• Posner, M. Boies, S. (1971). Components of attention. Psychological Review. 78(5), pp. 391–408. Available at: https://doi.org/10.1037/h0031333
• Styles, E. (2006). The Psychology of Attention (2nd ed.). Psychology Press. Available at: https://doi.org/10.4324/9780203968215.