Behavioural assays of the effects of antidepressant drug treatment on the functioning of catecholamine systems

The effects of antidepressant drugs on central beta-adrenergic and dopaminergic receptor function were investigated using the anorexic effects of low doses of amphetamine and apomorphine as assays of beta-adrenergic function and presynaptic dopamine function respectively. Anorexia was typically examined using a microstructural analysis of feeding, which was validated observationally. Amphetamine anorexia was characterized by a decrease in eating time and an increase in eating rate. At 0.5 mg/kg both beta-adrenergic and dopaminergic antagonists reversed anorexic effects, whilst anorexia at 1.0 mg/kg was reversed by dopaminergic antagonists only. An enhancement of amphetamine anorexia was seen following acute desmethylimipramine treatment! this effect was exactly compensated for over chronic treatment, implying no net change at beta-adrenergic synapses. However, applying amphetamine intracranially showed that approximately 75% of the acute enhancement of amphetamine anorexia was mediated peripherally, suggesting an attenuation of beta-receptor function during chronic antidepressant drug treatment. Some further data suggested that an alpha-adrenergic change could also have contributed to the antidepressant drug-induced attenuation of anorexia. Low doses of apomorphine, specific for presynaptic dopamine receptors, induced an anorexia characterized by decreases in both eating time and eating rate. The dopamine receptor antagonists haloperidol and thioridazine reversed apomorphine anorexia by reversing eating time but not eating rate. Administration of apomorphine into nuclei A9 and A10 reduced total food intake and eating time but not eating rate. These findings imply that presynaptic dopamine receptors mediate the effects of apomorphine on eating time. Acute treatment with desmethylimipramine, enhanced apomorphine anorexia. During chronic treatment the apomorphine-induced reduction in eating time was sometimes attenuated, suggesting a presynaptic dopamine receptor subsensitivity. Anorexia was also enhanced following acute desmethylimipramine treatment with intracranial administration of apomorphine. Again, there was no clear evidence of subsensitivity following chronic treatment, but some evidence for subsensitivity in nucleus A10 during withdrawal. The significance of a reduced beta-receptor function and an increased dopamine function following chronic antidepressant drug treatment are discussed in relation to the biological basis of depression

Assessing the Effectiveness of Automated Emotion Recognition in Adults and Children for Clinical Investigation

Recent success stories in automated object or face recognition, partly fuelled by deep learning artificial neural network (ANN) architectures, has led to the advancement of biometric research platforms and, to some extent, the resurrection of Artificial Intelligence (AI). In line with this general trend, inter-disciplinary approaches have taken place to automate the recognition of emotions in adults or children for the benefit of various applications such as identification of children emotions prior to a clinical investigation. Within this context, it turns out that automating emotion recognition is far from being straight forward with several challenges arising for both science(e.g., methodology underpinned by psychology) and technology (e.g., iMotions biometric research platform). In this paper, we present a methodology, experiment and interesting findings, which raise the following research questions for the recognition of emotions and attention in humans: a) adequacy of well-established techniques such as the International Affective Picture System (IAPS), b) adequacy of state-of-the-art biometric research platforms, c) the extent to which emotional responses may be different among children or adults. Our findings and first attempts to answer some of these research questions, are all based on a mixed sample of adults and children, who took part in the experiment resulting into a statistical analysis of numerous variables. These are related with, both automatically and interactively, captured responses of participants to a sample of IAPS pictures

Examination of the factor structure of the Schizotypal Personality Questionnaire (SPQ) among British and Trinidadian adults

Much debate in schizotypal research has centred on the factor structure of the Schizotypal Personality Questionnaire (SPQ), with research variously showing higher-order dimensionality consisting of two to seven dimensions. In addition, cross-cultural support for the stability of those factors remains limited. Here, we examined the factor structure of the SPQ among British and Trinidadian adults. Participants from a White British sub-sample (n = 351) resident in the UK and from an African Caribbean sub-sample (n = 284) resident in Trinidad completed the SPQ. The higher-order factor structure of the SPQ was analysed through confirmatory factor analysis, followed by multiple-group analysis for the model of best-fit. Between-group differences for sex and ethnicity were investigated using multivariate analysis of variance in relation to the higher-order domains. The model of best-fit was the four-factor structure, which demonstrated measurement invariance across groups. Additionally, these data had an adequate fit for two alternative models: a) 3 factors and b) a modified 4-factor. The British sub-sample had significantly higher scores across all domains than the Trinidadian group, and men scored significantly higher on the disorganised domain than women. The four-factor structure received confirmatory support and, importantly, support for use with populations varying in ethnicity and culture

High-Rate Convolutional Codes with CRC-Aided List Decoding for Short Blocklengths

Recently, rate-$1/\omega$ zero-terminated and tail-biting convolutional codes (ZTCCs and TBCCs) with cyclic-redundancy-check (CRC)-aided list decoding have been shown to closely approach the random-coding union (RCU) bound for short blocklengths. This paper designs CRCs for rate-$(\omega-1)/\omega$ CCs with short blocklengths, considering both the ZT and TB cases. The CRC design seeks to optimize the frame error rate (FER) performance of the code resulting from the concatenation of the CRC and the CC. Utilization of the dual trellis proposed by Yamada \emph{et al.} lowers the complexity of CRC-aided serial list Viterbi decoding (SLVD) of ZTCCs and TBCCs. CRC-aided SLVD of the TBCCs closely approaches the RCU bound at a blocklength of $128$.Comment: 6 pages; submitted to 2022 IEEE International Conference on Communications (ICC 2022

CRC-Aided High-Rate Convolutional Codes With Short Blocklengths for List Decoding

Recently, rate-1/n zero-terminated (ZT) and tail-biting (TB) convolutional codes (CCs) with cyclic redundancy check (CRC)-aided list decoding have been shown to closely approach the random-coding union (RCU) bound for short blocklengths. This paper designs CRC polynomials for rate- (n-1)/n ZT and TB CCs with short blocklengths. This paper considers both standard rate-(n-1)/n CC polynomials and rate- (n-1)/n designs resulting from puncturing a rate-1/2 code. The CRC polynomials are chosen to maximize the minimum distance d_min and minimize the number of nearest neighbors A_(d_min) . For the standard rate-(n-1)/n codes, utilization of the dual trellis proposed by Yamada et al. lowers the complexity of CRC-aided serial list Viterbi decoding (SLVD). CRC-aided SLVD of the TBCCs closely approaches the RCU bound at a blocklength of 128. This paper compares the FER performance (gap to the RCU bound) and complexity of the CRC-aided standard and punctured ZTCCs and TBCCs. This paper also explores the complexity-performance trade-off for three TBCC decoders: a single-trellis approach, a multi-trellis approach, and a modified single-trellis approach with pre-processing using the wrap around Viterbi algorithm.Comment: arXiv admin note: substantial text overlap with arXiv:2111.0792